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The clinical value of magnetic resonance angiography (MRA), transcranial Doppler ultrasound (TCD) and electroencephalogram (EEG) in the diagnosis of intracranial artery stenosis in ischemic cerebrovascular disease (ICVD) was explored. The clinical data of TCD, MRA and EEG in 98 patients with ICVD were retrospectively analyzed. The clinical value of TCD, MRA combined with EEG in the diagnosis of intracranial artery stenosis in ICVD was analyzed based on the results of digital subtraction angiography (DSA) as the gold standard. A total of 98 patients were diagnosed with 27 cases of normal intracranial artery, 32 cases of mild stenosis, 25 cases of moderate stenosis, and 14 cases of severe stenosis DSA examination. TCD was detected in 23 cases of normal, 25 cases of mild stenosis, 23 cases of moderate stenosis and 13 cases of severe stenosis. MRA showed 24 cases of normal, 28 cases of mild stenosis, 21 cases of moderate stenosis and 12 cases of severe stenosis. EEG examination detected that there were 25 cases of normal, 24 cases of mild stenosis, 22 cases of moderate stenosis, and 14 cases of severe stenosis. Sensitivity, accuracy and negative predictive value had significant differences between combined diagnosis and single diagnosis. The combined detection of TCD, MRA and EEG is consistent with DSA detection in the diagnosis of ICVD intracranial artery stenosis.

Purpose: Unilateral jugular stenosis is easily mistaken as jugular hypoplasia for their similar jugular appearances. This study aimed to propose a scheme to differentiate acquired internal jugular vein stenosis (IJVS) from congenital jugular variation through two case examples., Methods: We presented a dynamic evolution process of the IJVS formation, through a case of a 17-year-old female with paroxysmal nocturnal hemoglobinuria (PNH)-associated right internal jugular venous thrombosis (IJVT), which resulted in post-thrombotic IJVS in the rare context of rapid recanalization. Meanwhile, we compared her images with images of a 39-year-old healthy male with hypoplastic IJV to determine the differences between the acquired IJVS and congenital dysplasia., Results: Based on the first case, we noticed the whole formative process of acquired IJVS from nothing to something. Meantime, we found that acquired IJVS was surrounded by abnormal corkscrew collaterals as imaged on contrast-enhanced magnetic resonance venography (CE-MRV), and the ipsilateral jugular foramen (JF) was normal-sized as displayed on computer tomography (CT). Conversely, jugular hypoplasia was with ipsilateral stenotic JF and without serpentine collaterals., Conclusion: JF morphology and venous collaterals may be deemed as surrogate identifiers to distinguish acquired unilateral IJVS from jugular hypoplasia., (© 2022. The Author(s).)

The treatment of acute deep vein thrombosis has developed significantly over the past few years, and catheter-directed thrombolysis is now widely accepted. Controversy still exists over the decision to treat residual or underlying lesions with a venous stent. Magnetic resonance techniques have evolved considerably, which together with intravenous ultrasound can provide a detailed assessment of the deep venous system. Nevertheless, there is still no single perfect imaging modality that can identify a functional stenosis in the venous system. The decision to proceed to stent placement following lysis is multifactorial, reliant on the use of a number of imaging modalities in combination but most importantly good clinical acumen and experience., (© The Author(s) 2016.)

Objective: To evaluate the patterns, related factors and prognostic value of abnormal magnetic resonance angiography (MRA) in human immunodeficiency virus negative tuberculous meningitis., Materials and Methods: We performed a prospective study in patients aged >14 years. Abnormality on MRA was correlated with clinical, laboratory and magnetic resonance imaging findings. Modified Barthel index was used to assess outcome at 6 months after inclusion., Results: Of 101 patients included, MRA was abnormal in 45 (44.6%). The distribution of MRA abnormality was classified as disseminated irregular calibres of intracranial arteries with or without reduction in distant branches (29.7%, pattern 1) and localised stenosis at the base of the brain (26.7%, pattern 2). In logistic regression analysis, pattern 2 was related to stage of the disease (P = 0.002), basal exudates (P = 0.03) and infarction (P = 0.000), while pattern 1 was related to duration of disease (P = 0.050), hydrocephalus (P = 0.032) and age (P = 0.002). Pattern 1 was also correlated with infarction (P = 0.000), particularly infarction in the tubercular zone (P = 0.035) in univariate analysis. MRA abnormality was associated with paradoxical worsening (P = 0.022) and poor prognosis in univariate analysis (P = 0.035)., Conclusion: MRA abnormality is associated with stroke and poor outcomes. Although it indicates mild vascular injury, pattern 1 MRA abnormality is nevertheless associated with infarction and needs proper intervention.

Objectives: To compare the image quality and diagnostic performance of two non-contrast enhanced MR angiography (NCE-MRA) techniques using flow-sensitive dephasing (FSD) prepared steady-state free precession (SSFP) and quiescent-interval single-shot (QISS) for the calf arteries in patients with diabetes., Materials and Methods: Twenty six patients underwent the two NCE-MRA techniques followed by contrast-enhanced MRA (CE-MRA) of lower extremity on a 1.5T MR system. Image quality scores, arterial stenosis scores, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel sharpness, and diagnostic accuracy for detecting more than 50% arterial stenosis were evaluated and statistically compared using CE-MRA as the reference standard., Results: All examinations were performed successfully. Of the total 153 calf arterial segments obtained in the 26 patients, FSD and QISS showed no significant difference in the number of diagnostic arterial segments (151 [98%] vs. 147 [96%], respectively, P>0.05). The image quality of FSD was higher than that of QISS in the peroneal artery and posterior tibial artery (P<0.05), but no significant difference in the anterior tibial artery (P>0.05). SNR and CNR of FSD were higher than those of QISS (P<0.01), while FSD showed comparable vessel sharpness compared with QISS (P>0.05). The time efficiency of SNR and CNR between FSD and QISS showed no significant difference when taking into account the times for FSD-related scout scans. There was no difference in sensitivity (95% vs. 93%, P>0.05) and negative predictive value (98% vs. 97%, P>0.05) between FSD and QISS for detecting stenosis greater than 50%. However, FSD showed higher specificities (99% vs. 92%, P<0.05) and diagnostic accuracy (98% vs. 92%, P<0.05) compared to QISS., Conclusion: Both FSD and QISS had similar high sensitivity and negative predictive value for detecting calf arteries with over 50% stenosis, but FSD showed slightly higher diagnostic specificity and better depiction of arterial lesions due to its isotropic submillimeter spatial resolution. QISS, being an easier to use and less time-consuming technique, could be a method of choice for rapid screening of arterial disease of the lower extremity.

Purpose: Two-point fat-water separation methods are increasingly being used for chest and abdominal MRI and have recently been introduced for use in MR angiography of the lower extremities. With these methods, flowing spins can accumulate unintended phase shifts between the echo times. The purpose of this study is to demonstrate that these phase shifts can lead to inaccurate signals in the water and fat images., Theory and Methods: In vitro experiments were conducted at 1.5T and 3.0T using a stenosis-mimicking phantom and a computer-controlled pump to image a range of physiologically relevant velocities., Results: In the phantom images acquired using bipolar readout gradients, fat-water signal inaccuracies were visible in regions of flow, with increasing severity as the flow rate was increased. Additionally, similar effects were observed in regions of high flow in clinical chest and liver exams. In the phantom images, the effect was eliminated by using a dual-pass method without bipolar readout gradients., Conclusion: When using fat-water separation methods with bipolar readout gradients, phase shifts caused by the motion of spins can lead to signal inaccuracies in the fat and water images. These artifacts can be mitigated by using approaches that do not use bipolar readout gradients., (© 2014 Wiley Periodicals, Inc.)

The purpose of this study is to assess the image quality and diagnostic accuracy of non-contrast quadruple inversion-recovery balanced-SSFP MRA (QIR MRA) for detection of aortoiliac disease in a clinical population. QIR MRA was performed in 26 patients referred for routine clinical gadolinium-enhanced MRA (Gd-MRA) for known or suspected aortoiliac disease. Non-contrast images were independently evaluated for image quality and degree of stenosis by two radiologists, using consensus Gd-MRA as the reference standard. Hemodynamically significant stenosis (≥50%) was found in 10% (22/226) of all evaluable segments on Gd-MRA. The sensitivity and specificity for stenosis evaluation by QIR MRA for the two readers were 86%/86% and 95%/93% respectively. Negative predictive value and positive predictive value were 98%/98% and 63%/53% respectively. For stenosis evaluation of the aortoiliac region QIR MRA showed good agreement with the reference standard with high negative predictive value and a tendency to overestimate mild disease presumably due to the flow-dependence of the technique. QIR MRA could be a reasonable alternative to Gd-MRA for ruling out stenosis when contrast is contraindicated due to impaired kidney function or in patients who undergo abdominal MRA for screening purposes. Further work is necessary to improve performance and justify routine clinical use., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To compare the diagnostic performances of computer tomography angiography (CTA) and magnetic resonance angiography (MRA) for detection and assessment of stenosis in patients with autologuous hemodialysis access., Materials and Methods: Search of PubMed, MEDLINE, EMBASE and Cochrane Library database from January 1984 to May 2013 for studies comparing CTA or MRA with DSA or surgery for autologuous hemodialysis access. Eligible studies were in English language, aimed to detect more than 50% stenosis or occlusion of autologuous vascular access in hemodialysis patients with CTA and MRA technology and provided sufficient data about diagnosis performance. Methodological quality was assessed by the Quality Assessment of Diagnostic Studies (QUADAS) instrument. Sensitivities (SEN), specificities (SPE), positive likelihood ratio (PLR), negative likelihood values (NLR), diagnostic odds ratio (DOR) and areas under the receiver operator characteristic curve (AUC) were pooled statistically. Potential threshold effect, heterogeneity and publication bias was evaluated. The clinical utility of CTA and MRA in detection of stenosis was also investigated., Result: Sixteen eligible studies were included, with a total of 500 patients. Both CTA and MRA were accurate modality (sensitivity, 96.2% and 95.4%, respectively; specificity, 97.1 and 96.1%, respectively; DOR [diagnostic odds ratio], 393.69 and 211.47, respectively) for hemodialysis vascular access. No significant difference was detected between the diagnostic performance of CTA (AUC, 0.988) and MRA (AUC, 0.982). Meta-regression analyses and subgroup analyses revealed no statistical difference. The Deek's funnel plots suggested a publication bias., Conclusion: Diagnostic performance of CTA and MRA for detecting stenosis of hemodialysis vascular access had no statistical difference. Both techniques may function as an alternative or an important complement to conventional digital subtraction angiography (DSA) and may be able to help guide medical management.

Background and Purpose: Patterns of DWI findings that predict recurrent ischemic events after TIA are well-established, but similar assessments of intracranial MRA findings are not available. We sought to determine the imaging characteristics of MRA that are predictive of early recurrent stroke/TIA in patients with TIA., Materials and Methods: We performed a retrospective analysis of 129 consecutive patients with a clinical diagnosis of TIA in whom MR imaging was done within 24 hours of symptom onset. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of >50% stenosis or occlusion of symptomatic intracranial arteries for recurrent stroke/TIA at 7 days after TIA. We used logistic regression analysis to adjust for the clinical ABCD(2) score. We performed this analysis for symptomatic steno-occlusive lesions at any site and symptomatic steno-occlusive lesions on proximal large intracranial arteries (internal carotid artery, vertebral artery, basilar artery, and circle of Willis)., Results: Forty-two (32.5%) patients had acute ischemic lesions on DWI; 16 (12.4%) had significant MRA lesions, of which 11 (8.5%) were on proximal vessels. Nine patients had early recurrence (TIA, 7; minor stroke, 2). Only patients with proximal MRA lesions were at higher risk of early recurrence independent of the ABCD(2) score (adjusted odds ratio, 5.5; 95% confidence interval, 1.1-27.8; P = .04)., Conclusions: Proximal lesions of cerebral arteries seen on MRA were predictive of recurrent stroke/TIA at 7 days. These findings suggest that MRA could be used to improve the selection of patients with TIA at high risk of early recurrent stroke/TIA.

Aim: To evaluate electrocardiogram (ECG)-gated quiescent-interval single-shot magnetic resonance angiography (QISS-MRA) for nonenhanced assessment of peripheral artery occlusive disease (PAOD) using contrast-enhanced MRA (CE-MRA) as the reference standard., Materials and Methods: Twenty-seven patients (mean age 66.6 ± 10.8 years) with PAOD were included in the study. QISS-MRA and CE-MRA of the lower extremity were performed using a 1.5 T MR scanner. In each patient, subjective image quality and the degree of stenosis were evaluated on a four-point scale for 15 predefined arterial segments., Results: Twenty-five of the 27 patients were considered for analysis. Subjective image quality of QISS-MRA was significantly lower for the distal aorta, pelvic arteries, and femoral arteries as compared to CE-MRA (p < 0.01), while no significant difference was found for other vascular segments. The degree of stenosis was overestimated with QISS-MRA in 23 of 365 (6.3%) segments and underestimated in two of 365 (0.5%) segments. As compared to CE-MRA, QISS-MRA had a high sensitivity (98.6%), specificity (96%) as well as positive and negative predictive value (88.7 and 99.6%, respectively) for the detection of significant stenosis (≥50%)., Conclusion: ECG-gated QISS-MRA is a promising imaging technique for reliable assessment of PAOD without the use of contrast material., (Copyright © 2011 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Introduction: MRI and MRA are used for diagnosis and activity determination of patients with Takayasu's arteritis (TA). However, there is a limited experience regarding the role of MRI in long-term follow-up of those patients. The aim of the present study was to evaluate the clinical usefulness of MRI in the long-term follow-up of patients with Takayasu's disease., Materials and Methods: The clinical data of 11 TA patients, who obtained two or more follow-up MRI scans, was matched with the imaging results. MRI examinations were considered positive for disease activity when one of the following findings was noted: new arterial wall enhancement or interval appearance of anatomical changes (interval dilatation, stenosis or occlusion or new arterial wall irregularity). Conversely, MRI examinations were considered to show signs of improvement when local enhancement disappeared, or when a stenosis was relieved. Disease activity was determined by the combination of worsening localizing ischemic signs and symptoms, systemic signs and symptoms (malaise, fever, etc.), and elevated blood markers (CRP and ESR)., Results: A total of 47 MRI examinations were performed in 11 patients (1 male, mean age 28, range 14-53 years) with a total follow-up time ranging between 12 and 56 months (average 36 months). MRI was positive for active disease at least once in nine out of the 11 patients (82%). The most commonly affected arteries were the aortic arch, the left subclavian artery and the left common carotid artery. No statistically significant correlation was found between clinical activity and MRI signs of activity., Conclusion: Although MRI is a well established modality for primary diagnosis of TA, the present study suggests that it has a limited clinical role in the long-term follow-up of those patients when reactivation of disease is suspected., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The peroneal artery is the dominant supply of the osteomyocutaneous fibular flap. It has been shown that there can be anatomical variants that could jeopardise the blood supply to the lower limb during harvest of the flap. To avoid postoperative ischaemia of the lower leg, preoperative evaluation of adequate collateral perfusion is essential. We investigated whether magnetic resonance angiography (MRA) accurately shows anatomical variants and pathological stenoses of the vessels of the lower leg and whether it can replace conventional invasive techniques. Conventional digital subtraction angiography (DSA) was used in a prospective study of 15 patients, and contrast-enhanced MRA postoperatively. Arteries were evaluated by three radiologists for: size of vessel at the trifurcation; hypoplastic or missing vessels; appreciable stenosis or vascular occlusion, or both; atherosclerotic malformations; and overall vascular topography. High resolution MRA enabled a reliable judgement to be made of the vessels of the lower leg. MRA definitively detected hypoplastic vessels, stenoses, occlusion, or atherosclerotic changes of the vessels, and enabled both accurate assessment of the quality of vessels and the preferred site for the harvest of the flap. As it is a low risk procedure, it can be done in the outpatient department with no risk of radiation. It can easily replace conventional DSA., (Copyright © 2010 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Popliteal vascular entrapment syndrome is caused by aberrations or hypertrophy of the gastrocnemius muscles, which compress the neurovascular structures of the popliteal fossa, leading to symptoms of vascular and degeneration as well as aneurysm formation. Imaging of popliteal vascular entrapment may be performed with ultrasound, magnetic resonance imaging (MRI), computed tomography angiography, and conventional angiography. The use of blood-pool contrast agents in MRI when popliteal vascular entrapment is suspected offers the possibility to perform vascular imaging with first-pass magnetic resonance angiographic, high-resolution, steady-state imaging and allows functional tests all within one examination with a single dose of contrast agent. We present imaging findings in a case of symptomatic popliteal vein entrapment diagnosed by the use of blood pool contrast-enhanced MRI.

Background and Purpose: In-stent restenosis (ISR) after angioplasty/stenting for intracranial stenosis has been reported in up to 25% to 30% of patients. Detection and monitoring of ISR relies primarily on serial catheter angiography, because noninvasive imaging methods are typically hampered by stent-related artifact. We examined the value of serial vessel flow measurements using quantitative magnetic resonance angiography (QMRA) in detection of ISR., Material and Methods: Records of patients undergoing stenting for intracranial symptomatic stenosis >50% between 2005 and 2009 were retrospectively reviewed. Angiographic images were graded by a blinded neurointerventionalist for stenosis pretreatment, immediately after treatment, and during follow-up. Flow in the affected vessel measured by QMRA was recorded; > 25% reduction in flow was considered indicative of an adverse change. Clinical data regarding neurological outcome were also collected., Results: Twenty-eight patients underwent stenting during the time interval studied. Of these, 12 patients (mean age, 55.5 years; 8 female) had contemporaneous angiography and QMRA and were analyzed. Median follow-up was 9 months. Six patients (50%) demonstrated angiographic restenosis 2 to 12 months after treatment; all had an analogous decrease in flow in the vessel of interest. Of 3 patients with more severe flow decrement (> 50%), 2 experienced stroke. None of the patients without angiographic ISR demonstrated a flow decrease on QMRA., Conclusions: In this preliminary series, flow decrease on QMRA is highly predictive of angiographic ISR. Additionally, the degree of flow decrement correlates with symptomatic ISR. QMRA may provide a useful noninvasive tool for serial monitoring after intracranial stenting.

Purpose: Cardiovascular magnetic resonance assessment of adults late after an atrial redirection operation for transposition is demanding and time consuming. We hypothesised that the relatively fast and standardised 3-dimensional time-resolved contrast-enhanced magnetic resonance angiography, or dynamic angiography, would be valuable in the periodic follow-up of these patients., Methods: We investigated prospectively 36 adults with transposition using dynamic angiography, comparing our results against a comprehensive but non-contrast cardiovascular magnetic resonance protocol. We acquired 6 dynamic angiographic datasets after injection of contrast. The primary aim was to detect significant obstruction of the pathways for venous flow., Results: In 4 patients (11%), we found evidence of moderate-to-severe, and thus clinically important, obstruction of systemic venous channels on standard cardiovascular magnetic resonance. All these patients were correctly identified by dynamic angiography. In 4 additional patients, we found mild and haemodynamically insignificant obstructions in the systemic venous channels. Of the 8 (22%) patients with any obstruction, 6 were detected by angiography. There were no false positives reported, giving sensitivity of 75% and specificity of 100%, a positive predictive value of 100%, and negative predictive value of 93%. In 1 patient, there was a moderate obstruction of the pulmonary venous compartment which was not readily seen by dynamic angiography., Conclusions: 3-dimensional dynamic angiography is a useful method for detecting anatomically moderate-to-severe, but not mild, obstructions in the systemic venous channels following Mustard repair for transposition. This technique can be used as a single imaging method and/or as complimentary to standard two dimensional cardiovascular magnetic resonance techniques for detection of clinically important obstructions in the systemic venous channels.

Background: Magnetic resonance (MR)-guided vascular interventions are of increasing interest, and, with the use of contrast-enhanced techniques, intraarterial contrast-enhanced MR angiography (ia-ce-MRA) competes with intraarterial digital subtraction angiography (ia-DSA) for the diagnostic evaluation of the infrainguinal vessel tree., Purpose: To assess the diagnostic value of ia-ce-MRA and high-resolution T1-weighted (hr-T1w) imaging compared to the gold-standard ia-DSA for residual stenosis and local dissections after femoropopliteal recanalization in patients with peripheral arterial occlusive disease (PAOD)., Material and Methods: Eight patients with PAOD and short vessel occlusion of their femoropopliteal arteries underwent recanalization and balloon positioning under DSA. Patients were transferred to a short-bore MR scanner. Percutaneous transluminal angioplasty (PTA) was accomplished under MR fluoroscopy. Pre- and postinterventional ia-ce three-dimensional (3D) gradient-echo MRA with gadopentate dimeglumine was performed using the intraarterial introducer sheath. Maximum intensity projections (MIP) and multiplanar reconstructions (MPR) were calculated from the data set. High-resolution T1w images of the angioplasty region before and after dilatation were acquired. Control ia-DSA images were obtained., Results: The postinterventional angioplasty results for stenosis grading were comparable in ia-MRA and ia-DSA. Only two of five local dissections in ia-DSA were visualized with the ia-ce-MRA runs including MIPs and MPRs. To clearly depict dissection, hr-T1w images were needed., Conclusion: Grading of stenotic lesions with ia-ce-MRA after PTA is comparable to ia-DSA. Intraarterial ce-MRA with calculated MIPs and MPRs is only partially sufficient to visualize local dissections after PTA. High-resolution T1w images are required for precise diagnosis of dissections in magnetic resonance tomography.

For hypoplastic left heart syndrome (HLHS), there have been concerns regarding pulmonary artery growth and ventricular dysfunction after first stage surgery consisting of the Norwood procedure modified with a right ventricle-to-pulmonary artery conduit. We report our experience using cardiovascular magnetic resonance (CMR) to determine and follow pulmonary arterial growth and ventricular function in this cohort. Following first stage palliation, serial CMR was performed at 1 and 10 weeks post-operatively, followed by cardiac catheterization at 4-6 months. Thirty-four of 47 consecutive patients with HLHS (or its variations) underwent first stage palliation. Serial CMR was performed in 20 patients. Between studies, ejection fraction decreased (58 +/- 9% vs. 50 +/- 5%, p < 0.05). Pulmonary artery growth occurred on the left (6 +/- 1 mm vs. 4 +/- 1 mm at baseline, p < 0.05) but not significantly in the right. This trend continued to cardiac catheterization 4-6 months post surgery, with the left pulmonary artery of greater size than the right (8.8 +/- 2.2 mm vs. 6.7 +/- 1.9 mm, p < 0.05). By CMR, 5 had pulmonary artery stenoses initially, and at 2 months, 9 had stenoses. Three of the 9 underwent percutaneous intervention prior to the second stage procedure. In this cohort, reasonable growth of pulmonary arteries occurred following first stage palliation with this modification, although that growth was preferential to the left. Serial studies demonstrate worsening of ventricular function for the cohort. CMR was instrumental for detecting pulmonary artery stenosis and right ventricular dysfunction.

Purpose: To report our initial experience implementing a noncontrast-enhanced electrocardiograph (ECG) gated fast spin echo magnetic resonance angiography (MRA) technique for assessment of the calf arteries., Materials and Methods: Noncontrast MRA images of 36 clinical patients examined over a 6-month period were evaluated by two radiologists for length and degree of stenosis of arterial segments. Diagnostic confidence in the technique was also recorded. The reference standard was a consensus reading by both radiologists using the noncontrast technique combined with two gadolinium-enhanced techniques: bolus-chase and time-resolved imaging., Results: For stenosis evaluation the noncontrast technique demonstrated accuracy 79.4% (1083/1364), sensitivity 85.4% (437/512), and specificity 75.8% (646/852). The sequence demonstrated high negative predictive value (92.3%, 646/700). The technique had serious artifacts leading to poor diagnostic confidence in 17 patients (47.2%). These included motion (n = 7) and artifacts specific to the sequence, including inaccurate trigger delays (n = 5), linear artifact (n = 7), and vessel blurring (n = 5). When only patients in whom there was satisfactory diagnostic confidence were considered, accuracy, sensitivity, and negative predictive value were 92.2% (661/717), 92.4% (158/171), and 97.5% (503/516), respectively., Conclusion: Our results indicate that when technically successful, noncontrast-enhanced MRA using ECG-gated fast spin echo can provide accurate imaging of the calf and pedal arteries. However, further development and optimization are needed to improve the robustness of the technique., ((c) 2008 Wiley-Liss, Inc.)

Objective: Feasibility of intraarterial MR angiography of the renal arteries and comparison of the accuracy of intraarterial MR angiography with selective intraarterial digital subtraction angiography (DSA) for detection of stenoses., Materials and Methods: Ten consecutive patients (mean, 68 years) with suspected renal artery stenosis underwent a digital subtraction angiography and an intraarterial gadolinium-enhanced MR angiography, performed on a 1.5-T system. For intraarterial MR angiography 60 ml diluted contrast agent (10 ml gadodiamide in 50 ml 0.9% saline solution) was injected through a conventional angiography catheter placed in the suprarenal abdominal aorta using a flow rate of 3.5 ml/s. A three-dimensional (3D) gradient-echo sequence was performed. Differences in the quantitative measurement of stenoses of lesions between DSA and intraarterial MR angiography were evaluated by three observers. Overall impression of the intraarterial MR angiography was documented on a four-point scale (1 = excellent to 4 = poor). Interobserver variability was calculated., Results: Intraarterial MR angiography of the renal arteries was feasible in all patients (100%) with a mean overall impression of all images of 1.8 (SD: 0.71). One of 9 accessory renal arteries was not visualized with intraarterial MR angiography. The overall sensitivity/specificity for detection of significant stenoses (>or=50% stenosis) were 83%/87%. Interobserver variability of intraarterial MR angiography ranged between fair and substantial (0.359-0.622)., Conclusion: Intraarterial MR angiography of the renal arteries in humans is feasible and has an acceptable sensitivity in detecting stenoses using injections of diluted contrast agent at concentrations as low as 17%.

Purpose: To determine the diagnostic performance of contrast-enhanced MR angiography (CE-MRA) with four doses of gadobenate dimeglumine for detection of significant steno-occlusive disease of the carotid, renal, and pelvic vasculature., Materials and Methods: Eighty-four patients with suspected disease of the renal (n = 16), pelvic (n = 41), or carotid (n = 27) arteries underwent CE-MRA (3D-spoiled gradient-echo sequences) at 1.5T. CE-MRA was performed with gadobenate dimeglumine at 0.025, 0.05, 0.1, or 0.2 mmol/kg (23, 24, 19, and 18 patients, respectively) administered at 2 mL/sec. Accuracy, sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) for detection of significant disease (>50% stenosis or occlusion for renal/pelvic arteries; >70% stenosis or occlusion for carotid arteries) was determined by three fully blinded, independent radiologists using conventional digital subtraction angiography (DSA) as reference standard. All comparisons were tested statistically (ANOVA, chi-square, and Mantel-Haenszel tests as appropriate) and reader agreement (kappa) was assessed., Results: Values for accuracy, sensitivity, specificity, PPV, and NPV on CE-MRA were consistently higher for 0.1 mmol/kg gadobenate dimeglumine (accuracy = 95.2-97.3%, sensitivity = 84.2% (all readers), specificity = 96.9-99.2%, PPV = 80.0-94.1%, NPV = 97.6-97.7%). The greater accuracy of the 0.1 mmol/kg dose was significant (P < 0.01, all readers) compared to all other dose groups. Agreement between the three readers was good for all dose groups (kappa >/=0.58), with the highest percent agreement (85.7%) noted for the 0.1 mmol/kg dose., Conclusion: Significantly better diagnostic performance on CE-MRA of the renal, pelvic, and carotid arteries is achieved with a gadobenate dimeglumine dose of 0.1 mmol/kg bodyweight., ((c) 2007 Wiley-Liss, Inc.)

The aim of this study was to prospectively assess the accuracy of three-dimensional magnetic resonance (MR) angiography for evaluation of stenosis in the peripheral arterial system with a continuous moving table technique, with conventional MR angiography as reference. This study was approved by the local institutional review board; informed consent was obtained. Five healthy male volunteers (mean age, 27 years; range, 24-35 years) and four men and one woman (mean age, 63 years; range, 46-78 years) with peripheral arterial occlusive disease were examined. Images obtained with both techniques showed excellent concordance (Cohen kappa = 0.75). Images obtained with a conventional protocol had higher quality compared with those obtained with the continuous technique (mean, 1.07 +/- 0.25 [standard deviation] vs 1.58 +/- 0.6; P < .05); small vessels appeared sharper on them. For detection of significant stenosis and occlusion, accuracy, sensitivity, and specificity of the continuous technique were 92.8%, 100%, and 89.2%, respectively.

Purpose: To evaluate the usefulness of time-resolved three-dimensional (3D) magnetic resonance angiography (MRA) using diluted contrast agent (CA) in patients who had undergone a Fontan operation or bidirectional cavopulmonary connection (BCPC)., Materials and Methods: Time-resolved 3D MRA (10 dynamic data sets, two seconds per dynamic data set) using parallel imaging and keyhole data sampling was performed on 15 patients (median age=10 years, range=1-20 years) who had undergone a Fontan operation (N=11) or BCPC (N=4). Diluted gadolinium (Gd) contrast agent (CA) was intravenously injected into the arm and/or leg veins. The flow dynamics and morphology of pulmonary circulation, and lung perfusion were assessed., Results: Preferential or balanced pulmonary blood flow from each systemic vein was visualized on time-resolved 3D MRA in all patients. In addition, occlusion/stenosis of the central thoracic vein (N=4) and pulmonary artery (N=6), systemic venous (N=5) and arterial (N=6) collaterals, and lung perfusion defect (N=4) were identified. Persistent hepatic venous plexus, pulmonary arteriovenous malformation, and axillary arteriovenous fistula were delineated in three patients, respectively., Conclusion: Time-resolved 3D MRA with diluted CA is useful for evaluating patients who have undergone a Fontan operation or BCPC because it can reveal the flow dynamics and morphology of pulmonary circulation, and lung perfusion status., (Copyright (c) 2007 Wiley-Liss, Inc.)

Pulmonary vein pathologies often present a diagnostic challenge. Among the different imaging modalities used for the evaluation of pulmonary veins, magnetic resonance is the most comprehensive in assessing anatomy and pathophysiology at the same time. Bright blood cine sequences and contrast-enhanced magnetic resonance angiography outline the course and connections of the pulmonary veins. Phase-contrast velocity mapping measures flow patterns, velocities, and volumes throughout the pulmonary circulation. This paper reviews contemporary utilization of magnetic resonance in the evaluation of pulmonary venous abnormalities in children, based on our experience over the last 5 years and on that of other investigators. We summarize how magnetic resonance imaging enhances our understanding of pulmonary vein physiology and how it can influence the diagnostic approach to children and adults with a pulmonary venous pathology, and we discuss its limitations.

Objective: The diagnostic accuracy of magnetic resonance angiography (MRA) in the infrapopliteal arterial segment is not well defined. This study evaluated the clinical utility and diagnostic accuracy of time-resolved imaging of contrast kinetics (TRICKS) MRA compared with digital subtraction contrast angiography (DSA) in planning for percutaneous interventions of popliteal and infrapopliteal arterial occlusive disease., Methods: Patients who underwent percutaneous lower extremity interventions for popliteal or tibial occlusive disease were identified for this study. Preprocedural TRICKS MRA was performed with 1.5 Tesla (GE Healthcare, Waukesha, Wis) magnetic resonance imaging scanners with a flexible peripheral vascular coil, using the TRICKS technique with gadodiamide injection. DSA was performed using standard techniques in angiography suite with a 15-inch image intensifier. DSA was considered the gold standard. The MRA and DSA were then evaluated in a blinded fashion by a radiologist and a vascular surgeon. The popliteal artery and tibioperoneal trunk were evaluated separately, and the tibial arteries were divided into proximal, mid, and distal segments. Each segment was interpreted as normal (0% to 49% stenosis), stenotic (50% to 99% stenosis), or occluded (100%). Lesion morphology was classified according to the TransAtlantic Inter-Society Consensus (TASC). We calculated concordance between the imaging studies and the sensitivity and specificity of MRA. The clinical utility of MRA was also assessed in terms of identifying arterial access site as well as predicting technical success of the percutaneous treatment., Results: Comparisons were done on 150 arterial segments in 30 limbs of 27 patients. When evaluated by TASC classification, TRICKS MRA correlated with DSA in 83% of the popliteal and in 88% of the infrapopliteal segments. MRA correctly identified significant disease of the popliteal artery with a sensitivity of 94% and a specificity of 92%, and of the tibial arteries with a sensitivity of 100% and specificity of 84%. When used to evaluate for stenosis vs occlusion, MRA interpretation agreed with DSA 90% of the time. Disagreement occurred in 15 arterial segments, most commonly in distal tibioperoneal arteries. MRA misdiagnosed occlusion for stenosis in 11 of 15 segments, and stenosis for occlusion in four of 15 segments. Arterial access was accurately planned based on preprocedural MRA findings in 29 of 30 patients. MRA predicted technical success 83% of the time. Five technical failures were due to inability to cross arterial occlusions, all accurately identified by MRA., Conclusion: TRICKS MRA is an accurate method of evaluating patients for popliteal and infrapopliteal arterial occlusive disease and can be used for planning percutaneous interventions.

Introduction: Optic nerve sheath fenestration or ventricular shunting are classically proposed after failure of medical treatment. Idiopathic intracranial hypertension is caused by venous sinus obstruction in an unknown percentage of cases. Recently, endoluminal venous sinus stenting was proposed as an alternative treatment., Patients and Method: Between September 2003 and December 2004, eight consecutive patients with a diagnosis of idiopathic intracranial hypertension underwent MRI venography and direct retrograde cerebral angiography., Results: There were five females and three males aged 22 to 55 years. All patients had vision disorders. The cerebrospinal fluid pressure ranged from 27 to 45 mmHg with normal composition. All patients presented at least one sinus stenosis. Endovascular stenting of the stenotic venous sinus was performed under intravenous heparin administration. Anti-platelet therapy was administered for 3 months post treatment. Intra-sinus pressures were invariably reduced by stenting. Mean follow-up was 18 months. All patients improved clinically. The cerebrospinal fluid pressure had normalized at 3-month follow-up in all patients. In all patients, multidetector row CT-angiography or MRI venography was performed at 3-, 6- and 12-month follow-up and demonstrated the patency of the stent., Discussion: The importance of venous sinus disease as a cause of idiopathic intracranial hypertension is probably underestimated. Patients with idiopathic intracranial hypertension should be evaluated with direct retrograde cerebral venography and manometry. In patients with venous sinus lesions, treatment by an endoluminal venous sinus stent is a safe and effective alternative for amenable lesions.

Purpose: To prospectively determine the diagnostic performance of a combination of standard bolus-chase magnetic resonance (MR) angiography and MR angiography with time-resolved imaging of contrast kinetics (TRICKS) for depicting severity of peripheral vascular disease of the lower extremity, including the pedal arteries, in diabetic patients with digital subtraction angiography (DSA) as the reference standard., Materials and Methods: An ethical committee approved this study; written informed consent was obtained from patients. Standard three-station and TRICKS MR angiography of the calf and foot were performed in 31 consecutive diabetic patients (23 men, eight women; mean age, 67 years; range, 43-81 years). Two readers separately assessed images of arterial segments as diagnostic or nondiagnostic and graded stenosis. Results were compared with those at DSA when the corresponding arterial segments were considered diagnostic at DSA. Wilcoxon signed rank test was used to determine if a significant difference between imaging techniques existed, and kappa statistics were used to determine interobserver agreement., Results: The difference between standard MR angiography and DSA regarding the number of diagnostic segments in the thigh was not significant (P = .50). A significantly higher number of calf and foot segments was considered diagnostic at TRICKS MR angiography than at standard MR angiography (P < .025). Sixteen of 26 segments in the foot that were considered nondiagnostic at DSA were considered diagnostic at TRICKS MR angiography. Average sensitivity of standard MR angiography for depicting hemodynamically significant arterial stenosis was 84% (reader 1) and 83% (reader 2) in the thigh and 78% (reader 1) and 80% (reader 2) in the calf. For both readers, average specificity was 97% in the thigh and 90% in the calf. Sensitivity and specificity of TRICKS MR angiography in the calf and foot were improved compared with those at standard MR angiography., Conclusion: TRICKS MR angiography of the distal calf and pedal vessels is superior to standard MR angiography regarding the number of diagnostic segments and assessment of the degree of luminal narrowing., ((c) RSNA, 2007.)

Purpose: Prospective evaluation of diagnostic accuracy of single field-of-view contrast-enhanced MR Angiography (ceMRA) with 1.0M gadobutrol compared to intraarterial DSA in body arteries., Materials and Methods: In an European multicenter study 179 patients underwent ceMRA and DSA. For each indication five prospectively defined vessel segments were evaluated by local investigators onsite and by three site-independent blinded readers (BR) independently., Results: The agreement between ceMRA and DSA diagnosis was statistically significant in the onsite (96.6%) and blinded reader (86.6-90.2%) evaluation. Sensitivity, specificity, accuracy, positive (PPV) and negative predictive values (NPV) for detection of relevant stenosis (>50%) were calculated for the right and left internal carotid arteries, and common and external iliac arteries: Sensitivity was 95-98% (onsite) and 76-96% (BR), specificity 94-96% (onsite) and 86-94% (BR), accuracy 96% (onsite) and 87-93% (BR), NPV 98-99% (onsite) and 84-98% (BR), and PPV 79-93% (onsite) and 44-91% (BR), respectively., Conclusion: CeMRA of body arteries using 1.0M gadobutrol provides diagnostic information comparable to intraarterial DSA.

Background and Purpose: To systematically analyze conventional angiographic (CA) features of children with primary central nervous system angiitis (cPACNS), to compare and correlate CA and MR angiography (MRA) lesion characteristics, and to define the sensitivity and specificity of MRA with CA as a reference standard., Methods: A retrospective, single-center cohort study of consecutive patients with cPACNS was performed. Patients with CA and MRA studies at diagnosis were included. Imaging studies were blindly reviewed by 2 neuroradiologists using a standard analysis protocol. CA and MRA studies were compared using nonparametric analysis., Results: Of 45 patients with MRA at diagnosis, there were 25 for whom CA and MRA studies were performed within 1 month of each other. These comprised the study group. The CA distribution of lesions was multifocal (76%) and proximal (86%) (P < .05) with a trend toward unilaterality (P = .06) with anterior circulation involvement (P = .08). The sensitivity and specificity of MRA for CA abnormality was 70% and 98%, respectively. There was no significant difference between MRA and CA for lesion detection or characterization (P = .87), and the modalities showed a fair correlation (kappa = 0.4)., Conclusion: Angiographic lesions are multifocal and occur proximally and unilaterally within the anterior circulation. There is no significant difference in the ability of MRA to detect and characterize lesions when compared with CA.

The fusion imaging of the 3D MR cisternography (MRC) and 3D MR angiography (MRA) was applied for the assessment of the major cerebral arterial stenosis. The outer wall configurations of the stenotic lesions of the intracranial major cerebral arteries within a cisternal space were depicted by 3D MRC. Flow-related vascular structures were shown by 3D MRA. Fusion imaging was created by compositing volumetric data of MRC and co-registered MRA by using a workstation with transparent perspective volume-rendering technique. Stenotic lesions of the intracranial cerebral arteries were assessed as a discrepancy of 3D MRC and 3D MRA findings on a fusion image. Fusion imaging of 3D MRC/MRA could visualize stenotic lesions of the intracranial major cerebral arteries caused by atherosclerotic plaques; and this may provide useful information in the management of acute and chronic ischemic stroke caused by atherosclerosis of the intracranial major cerebral arteries.

Purpose: To prospectively evaluate the accuracy of intraarterial magnetic resonance (MR) angiography in the depiction of significant stenoses and occlusions, with intraarterial digital subtraction angiography (DSA) serving as the reference standard., Materials and Methods: Approval of the local ethics committee and informed consent were obtained. Twenty patients (11 men; nine women; age range, 48-86 years; mean age, 69.5 years+/-11.2 [standard deviation]) with symptomatic peripheral arterial occlusive disease (PAOD) were prospectively enrolled. After percutaneous transluminal angioplasty (PTA), intraarterial MR angiography was performed in the thigh and the calf with a 1.5-T MR imager in two consecutive runs. Intraarterial MR angiography was performed with a low-dose injection protocol (ie, two 20-mL injections of a 50-mmol gadolinium-based contrast agent). Moderate stenoses (luminal narrowing50%) or vessel occlusions; 95% confidence intervals (CIs) were calculated for sensitivity and specificity., Results: Intraarterial DSA revealed 78 moderate stenoses, 57 significant stenoses, and 28 occlusions. Sensitivity, specificity, and accuracy of intraarterial MR angiography in the characterization of significant stenoses or occlusions were 92% (95% CI: 72%, 99%), 94% (95% CI: 82%, 98%), and 93%, respectively, in femoropopliteal arteries and 93% (95% CI: 83%, 98%), 71% (95% CI: 51%, 86%), and 86%, respectively, in infrapopliteal arteries. The main artifact observed with intraarterial MR angiography was venous contamination (12%)., Conclusion: Intraarterial MR angiography is an accurate method used to depict significant stenoses and occlusions in lower extremity arteries with a low-dose injection protocol., (Copyright (c) RSNA, 2006.)

The purpose of this study was to evaluate the technique of whole-body magnetic resonance angiography (MRA) of patients with a standard clinical scanner. Thirty-three patients referred for stenoses, occlusions, aneurysms, assessment of patency of vascular grafts, vasculitis and vascular aplasia were examined in a 1.5-T scanner using its standard body coil. Three-dimensional sequences were acquired in four stations after administration of one intravenous injection of 40 ml conventional gadolinium contrast agent. Different vessel segments were evaluated as either diagnostic or nondiagnostic and regarding the presence of stenoses with more than 50% diameter reduction, occlusions or aneurysms. Of 923 vessel segments, 67 were not evaluable because of poor contrast filling (n=31), motion artefacts (n=20), venous overlap (n=12) and other reasons (n=4). Stenoses of more than 50%, occlusions or aneurysms were observed in 26 patients (129 segments). In nine patients additional unsuspected pathology was found. In 10 out of 14 patients (71/79 segments) there was conformity between MRA and digital subtraction angiography regarding the grade of stenosis. This study shows that whole-body MRA with a standard clinical scanner is feasible. Motion artefacts and the timing of the contrast agent through the different segments are still problems to be solved.

Objective: Several imaging modalities are available for the evaluation of dysfunctional hemodialysis shunts. Color Doppler ultrasonography (CDUS) and digital subtraction angiography (DSA) are most widely used for the detection of access stenoses, and contrast-enhanced magnetic resonance angiography (CE-MRA) of shunts has recently been introduced. To date, no study has compared the value of these three modalities for stenosis detection in dysfunctional shunts. We prospectively compared CDUS and CE-MRA with DSA for the detection of significant (> or = 50%) stenoses in failing dialysis accesses, and we determined whether the interventionalist would benefit from CDUS performed before DSA and endovascular intervention., Methods: CDUS, CE-MRA, and DSA were performed of 49 dysfunctional hemodialysis arteriovenous fistulas and 32 grafts. The vascular tree of the accesses was divided into three to eight segments depending on the access type (arteriovenous fistula or arteriovenous graft) and the length of venous outflow. CDUS was performed and assessed by a vascular technician, whereas CE-MRA and DSA were interpreted by two magnetic resonance radiologists and two interventional radiologists, respectively. All readers were blinded to information from each other and from other studies. DSA was used as reference standard for stenosis detection., Results: DSA detected 111 significant (> or = 50%) stenoses in 433 vascular segments. Sensitivity and specificity of CDUS for the detection of significant stenosed vessel segments were 91% (95% CI, 84%-95%) and 97% (95% CI, 94%-98%), respectively. We found a positive predictive value of 91% (95% CI, 84%-95%) and a negative predictive value of 97% (95% CI, 94%-98%). The sensitivity, specificity, positive predictive value, and negative predictive value of MRA were 96% (95% CI, 90%-98%), 98% (95% CI, 96%-99%), 94% (95% CI, 88%-97%), and 98% (95% CI, 96%-99%), respectively. CDUS and CE-MRA depicted respectively three and four significant stenoses in six nondiagnostic DSA segments. The interventionalist would have chosen an alternative cannulation site in 38% of patients if the CDUS results had been available., Conclusions: We suggest that CDUS be used as initial imaging modality of dysfunctional shunts, but complete access should be depicted at DSA and angioplasty to detect all significant stenoses eligible for intervention. CE-MRA should be considered only if DSA is inconclusive.

Purpose: To evaluate the accuracy and clinical role of gadolinium-enhanced 3D magnetic resonance angiography (MRA) in patients with suspected hepatic arterial complications after liver transplantation., Materials and Methods: Thirty-six consecutive MRA studies were performed in 33 liver transplant recipients after transplantation. MRA image quality was assessed subjectively. Thirty-two MRA studies were retrospectively reviewed and correlated with surgery (n = 2), conventional angiography (n = 18), or clinical follow-up (n = 12). MRA findings were also correlated with those of Doppler sonography in 30 of the cases. In 20 cases, concordance between MRA and surgery or conventional angiography was evaluated for each grade of hepatic artery stenosis (normal, mild [<50%], moderate [50-75%], severe [>75%], or occluded)., Results: MRA image quality was degraded 13 of 36 cases (36.1%) studies. The sensitivity, specificity, and accuracy of MRA by consensus reading for more than 50% of hepatic artery stenosis or occlusion were 67%, 90%, and 81.3%, respectively. Of the 19 cases in which Doppler sonography was abnormal, MRA correctly characterized hepatic artery stenosis in 16 (84.2%). MRA also correctly identified all 5 occurrences of celiac artery stenosis. However, MRA overestimated the severity of hepatic arterial stenosis in 3 (15%) of 20 cases and underestimated 5 (25%) of 20 cases., Conclusion: MRA complements Doppler ultrasound to exclude significant hepatic artery stenosis. However, a substantial number of MRA studies were technically inadequate, and MRA demonstrated limited efficacy for correctly grading the severity of hepatic artery stenosis.

Objective: To evaluate the clinical application of three-dimensional dynamic contrast-enhanced MR angiography (3D DCE MRA) in diagnosis of angiostenosis after liver transplantation., Methods: Twenty recipients of liver transplantation underwent 3D DCE MRA examination. The blood vessel rating grades were accessed and the relative diameter of vascular anastomosis was measured; and the results were compared with those of US or DSA examination., Results: Satisfactory angiography images were obtained in all cases by 3D DCE MRA, including 11 cases with normal and mild stenosis, 5 with moderate and 4 with severe stenosis in hepatic artery. Except one case in which 3D DCE MRA showed severe stenosis but DSA showed moderate stenosis, the results of MRA were all consistent with those of US or/and DSA in the stenosis degree of the portal vein, hepatic vein and the postcava., Conclusion: 3D DCE MRA is an effective technique to evaluate the degree of angiostenosis after liver transplantation.

Purpose: To compare the accuracy of contrast material-enhanced three-dimensional (3D) dedicated calf magnetic resonance (MR) angiography with that of bolus-chase MR angiography, with conventional angiography as the reference standard, in patients with symptomatic peripheral vascular disease (PVD)., Materials and Methods: Thirty men with symptomatic PVD were examined. MR angiography was performed at 1.5 T before conventional angiography. MR angiographic examination included 3D contrast-enhanced dedicated calf MR angiography and three-station bolus-chase MR angiography. Two radiologists blinded to conventional angiographic results evaluated the MR angiograms independently. Two angiographers evaluated the conventional angiograms in consensus. Calf artery segments were graded as having 50% or less stenosis, greater than 50% stenosis, or occlusion or as being nondiagnostic. Statistical analyses were performed with paired permutation testing., Results: Analyses of 472 calf segments and 420 pelvic and thigh segments were performed. Of the 472 calf segments, three and 75 segments (reader 1) and seven and 91 segments (reader 2) were graded as nondiagnostic at dedicated calf MR angiography and bolus-chase MR angiography, respectively. Differences in diagnostic grade between the two examinations were significant (P <.001), accounting for within-subject correlations, with a mean estimated difference of -17.1% (95% confidence interval [CI]: -25.8%, -8.4%). In the calf arteries, the dedicated and bolus-chase MR angiographic sequences had diagnostic accuracies, respectively, of 81.5% (reader 1) and 79.1% (reader 2) and of 67.8% (reader 1) and 63.4% (reader 2). The dedicated calf sequence was significantly more accurate than the bolus-chase sequence (P =.001). The point estimate of the difference was 14.7%, with estimated correct diagnosis rates of 80.3% and 65.6% for the dedicated calf and bolus-chase examinations, respectively (95% CI for difference: 4.0%, 25.4%). The diagnostic accuracy of bolus-chase MR angiography at the pelvis-thigh level was slightly higher when it was performed first: 81.9% (reader 1) and 83.8% (reader 2) versus 74.3% (reader 1) and 80.0% (reader 2) when it was performed last. The difference was not significant (P =.21)., Conclusion: Use of dedicated calf MR angiography led to significantly increased diagnostic accuracy in the calf arteries compared with standard bolus-chase MR angiography. Use of the dual-bolus technique did not jeopardize the diagnostic accuracy in the pelvic and thigh arteries., (Copyright RSNA, 2004)

We report a rare case of bilateral pericallosal artery ectasia with stenosis in a 49-year-old man complaining of frontal headache. CT showed a serpiginous calcified interhemispheric fissure lesion with contrast enhancement. Imaging of this lesion was pursued with MR and MR angiography; however, conventional cerebral angiography was needed to make a definitive diagnosis.

Aim: To evaluate two-dimensional time of flight (2D TOF) and three-dimensional contrast-enhanced magnetic resonance angiographic (3DCE MRA) techniques in the assessment of patients with suspected thoracic outlet syndrome (TOS) of vascular origin., Materials and Methods: Fifty-five consecutive examinations, in 51 patients with suspected TOS of vascular origin, were examined using either a 1T or 1.5T Siemens magnetic resonance imaging (MRI) unit, using either 2D TOF (n=13) or 3DCE MRA (n=42). Examinations were performed with the arms abducted (n=27) or both abducted and adducted (n=28). The source images and MIPs were reviewed retrospectively and assessed for image quality and the presence of significant persistent stenosis or impingement (a >60% reduction in the diameter of the subclavian vessels at the thoracic outlet or evidence of post-stenotic dilatation). When significant impingement was identified, the images were reformatted with multiplanar reconstruction to determine the cause., Results: Images were sub-optimal in 53% 2D TOF and 10% 3DCE MRA examinations. 3DCE MRA offered vessel coverage from the aortic arch to the distal axilliary arteries, whereas, 2D TOF sequences gave more limited coverage. Eight patients were found to have significant impingement (n=7) or stenosis (n=1) of the subclavian artery attributable to TOS. 3DCE MRA also demonstrated other relevant significant stenoses not attributable to TOS (n=5). All cases of impingement were either seen only, or more prominently, on sequences with the arms abducted. Reformatting the 3DCE MRA studies demonstrated the cause of impingement., Conclusions: Both 2D TOF and 3DCE MRA may demonstrate TOS with significant arterial impingement. In comparison with 2D TOF sequences, 3DCE MRA offers extensive vessel coverage, is less prone to artefact and frequently demonstrates the underlying cause of TOS when studies are reformatted. Evidence of impingement should be sought from sequences performed with the arms abducted and venous phase sequences may show corroborative venous impingement.

Background: Venous sinus disease must be excluded before diagnosing idiopathic intracranial hypertension but is found only rarely in typical cases. Magnetic resonance venography (MRV) is the technique of choice for investigating this, and provides images that are diagnostic and easy to interpret. However, recent work using more invasive techniques has documented pressure gradients and stenoses in the lateral venous sinuses in many cases of idiopathic intracranial hypertension., Objective: To examine the reason for this discrepancy and to establish whether there are characteristic appearances on MRV in idiopathic intracranial hypertension that are routinely overlooked in clinical practice., Methods: MRVs from 20 patients with idiopathic intracranial hypertension were reviewed, unblinded, by two neuroradiologists, and their appearances rated for focal narrowings and signal gaps. A control group of 40 asymptomatic volunteers, matched for age and sex with the patient group, was recruited prospectively for MRV, and their scans rated in the same way., Results: The lateral sinuses presented a range of appearances with quite different distributions in the two groups (p<0.001). Bilateral lateral sinus flow gaps were seen in 13 of 20 patients with idiopathic intracranial hypertension and in none of 40 controls., Conclusions: A historical failure to use normal healthy controls to establish the boundaries between imaging artefact, normal anatomical variant, and disease means that the pathological significance of the different appearances of the lateral sinuses on MRV has not so far been appreciated.

Background: Arteriovenous (AV) fistulas are crucial in patients requiring long-term hemodialysis (HD). Dysfunctions of these fistulas are the most common causes of recurrent hospitalizations. This study aimed to evaluate the feasibility, safety and usefulness of contrast-enhanced magnetic resonance angiography (CE-MRA) in the evaluation of HD fistulas complications, and the condition of the central veins before HD access., Methods: This study comprised 30 consecutive patients (15 females, 15 males; age range 25-66 yrs, mean +/- SD 51.2 +/- 9.9 yrs). Of 30 patients, 26 had native AV fistulas and the remaining four patients, who had a history of previous subclavian vein catheterization, were candidates for HD fistulas. Nine patients had a radiocephalic fistula, 15 had a brachiobasilic fistula, one had a saphenous vein graft, and one had brachiobasilic vein transposition. To observe the fistula complications in these cases, three-dimensional (3-D) CE-MRA using gadolinium was performed., Results: The results were considered normal in three patients (10%), who were candidates for AV fistula construction; one patient had central vein occlusion due to previous catheterization. Thirteen patients (43.3%) had venous stenosis or occlusion; three of them (10%) had low CE arteries distal to fistula region, leading to ischemic complications, and six (20%) had stenosis at the fistula region. Seven patients (23.3%) had venous pseudoaneurysms, whereas two of them had both pseudoaneurysms and fistula region stenosis, and one had both venous stenosis and pseudoaneurysm. There were no adverse or allergic-like reactions or heat and taste sensations observed in our series., Conclusions: 3-D CE-MRA is a useful, safe and a practical imaging modality in complicated fistula diagnosis with fewer complications and side-effects in comparison to fistulography.

We reviewed 1440 MRA studies to identify patients with middle cerebral artery stenosis (MCAS). We identified 99 cases, and after reviewing the clinical records, classified 28 as asymptomatic MCAS (AMCAS), a prevalence of 2%. Suspected stroke was the most frequent indication for MRA. Follow-up was available for 21, mean 46.7 months (range 2.4-75.6 months). One stroke occurred in the AMCAS territory (5%), other strokes in five patients (24%). There were five deaths in patients with MCAS; age > 69 (P = 0.045) was the only associated risk factor. This study suggests that patients in whom MRA is performed and shows AMCAS may be at increased risk of strokes in any vascular distribution or of death.

Recent technological advances in magnetic resonance imaging have transformed the field of magnetic resonance angiography (MRA) from a research tool into an important clinical examination that is gaining acceptance as the screening modality of choice in evaluation of vascular disease. This article describes some of the new techniques and applications of MRA in clinical practice today.

Vascular disease produces changes in lumenal shape evident in magnetic resonance angiography (MRA). However, quantification of vascular shape from MRA is problematic due to image artifacts. Prior deformable models for vascular surface reconstruction primarily resolve problems of initialization of the surface mesh. However, initialization can be obtained in a trivial manner for MRA using isosurfaces. We propose a methodology for deforming the isosurface to conform to the boundaries of objects in the image with minimal a priori assumptions of object shape. As in conventional methods, external forces attract the surface toward edges in the image. However, smoothing is produced by a moment that aligns the normals of adjacent surface triangles. Notably, the moment produces no translational motion of surface triangles. The deformable isosurface was applied to a digital phantom of a stenotic artery, to MRA of three renal arteries with atherosclerotic disease and MRA of one carotid artery with atherosclerotic disease. Results of the surface reconstruction from the deformable model were compared with conventional X-ray angiography for the renal arteries. Measurement of the degree of stenosis of the renal arteries was within 12% +/- 6%. The deformable model provided improvements over the isosurface in all cases in terms of measurement of the degree of stenosis or improving the surface smoothness.

To evaluate major cerebral arterial stenotic lesions within a cisternal space, the outer wall contours of the arteries were depicted on three-dimensional (3D) MR cisternograms. The 3D MR cisternograms were reconstructed by perspective volume-rendering algorithm from the source volume data obtained from the T2-weighted 3D fast spin-echo sequence. Those images were compared with coordinated 3D MR angiograms, and then with 3D CT angiograms through the similar visual projections. The presence of stenotic lesions was indicated by the morphological discrepancy between the outer wall configuration of the itracisternal stenotic artery depicted on the 3D MR cisternograms and the intraluminal boundary shown on the 3D CT angiograms. With application of these techniques, spatial expansion of the stenotic lesions was able to be visualized. In this way, clinical 3D evaluation of the therapeutic effect on and follow-up of intracisternal major cerebral arterial stenotic lesions would be possible in patients with acute ischemic stroke.

Background: Radiofrequency catheter ablation (RFCA) is a promising intervention to treat atrial fibrillation. However, pulmonary vein (PV) stenosis after RFCA has been reported. The aim of this study was to investigate the incidence and time course of pulmonary vein stenosis after RFCA within a period of 3 months. Contrast-enhanced magnetic resonance angiography (MRA) was used to visualize pulmonary veins and was compared with radiographic angiography., Methods and Results: Forty-six consecutive patients with symptomatic paroxysmal atrial fibrillation had RFCA in the orifice of 138 pulmonary veins. Comparison of diameters measured in 44 untreated vessels either by radiographic angiography or with MRA established the reliability of MRA (r=0.934). MRA measurements revealed an incidence of relevant diameter reductions of > or =25% or stenosis of > or =50% after RFCA of 25 of 138 (18.1%) treated vessels 1 day and/or 3 months after ablation. A progression of diameter reduction after RFCA was observed in 8.3% (maximum 75%), whereas a regression was observed in 6.3% of treated PVs. Ablation at a radial angle of >180 degrees of a pulmonary vein orifice increased the risk of diameter reduction significantly compared with ablation at a radial angle < or =180 degrees (P=0.002)., Conclusions: The occurrence and progression of PV stenosis is a potential significant complication of RFCA in the orifice of pulmonary veins. These findings may have an impact on the technical performance of this intervention. In addition, long-term studies will be necessary to evaluate lumen reduction over time. MRA is a noninvasive, reproducible imaging modality for this purpose.

Purpose: To assess the feasibility and accuracy of multiphase contrast-enhanced magnetic resonance angiography (CE-MRA) in patients with dysfunctioning hemodialysis arteriovenous fistulae (AVF), using digital subtraction angiography (DSA) as the standard of reference., Materials and Methods: Fifteen patients with dysfunctioning AVF (eight radiocephalic and seven graft AVF) underwent CE-MRA. Dysfunction was defined as a flow decline of more than 25% in 1 month measured by dilutional flow measurements. CE-MRA was performed during injection of 35 mL of gadolinium-DTPA. The CE-MRA sequence consisted of a time-resolved series of 10 scans, each lasting approximately 10 seconds. The technical parameters were TR/TE/FA/voxel = 5.4/1.6/40/3.1 mm(3), and a rectangular surface reception coil was used. All patients were scheduled to undergo DSA at which an intervention was carried out when a stenosis >or=50% was seen. Two observers, unaware of each other's findings and the findings at DSA, quantified the number and degree of stenosis in the failing AVF. Image quality for CE-MRA and DSA was scored on a 3-point scale. The diagnostic performance of CE-MRA was analyzed with receiver-operator characteristic (ROC) analysis., Results: CE-MRA and DSA examinations were performed without side effects in all 15 patients. Image quality was scored significantly better on CE-MRA (observer 1: CE-MRA, 2.0; DSA, 1.3; P =.001; observer 2: CE-MRA, 2.0; DSA, 1.4; P =.002). Interobserver agreement for detection of >or=50% stenosis was 0.81 (95% confidence interval (CI) = 0.71-0.92) for CE-MRA and 0.69 (95% CI = 0.55-0.84) for DSA. ROC analysis revealed a mean area under the curve of 0.78. On the patient level, at the >or=50% threshold, mean sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100% (95% CI = 69%-100%), 10% (95% CI = 0%-78%), 70% (95% CI = 38%-92%), and 100% (95% CI = 50%-100%), respectively. At the >or=75% threshold, mean sensitivity, specificity, PPV, and NPV were 75% (95% CI = 20%-99%), 78% (95% CI = 39%-98%), 55% (95% CI = 12%-96%), and 89% (95% CI = 52%-100%), respectively., Conclusion: CE-MRA is a useful diagnostic tool for detecting stenoses in flow-declined hemodialysis AVF prior to interventional DSA., (Copyright 2002 Wiley-Liss, Inc.)

Introduction/objective: To evaluate the potential influence of various concentrations of gadolinium (Gd)-DTPA on magnetic resonance phase contrast (MR PC) velocimetry., Material and Methods: Imaging was done with a 1.0 T scanner using a standard Flash 2D sequence and a circular polarized extremity coil. In a validated flow phantom with a defined 75% area stenosis different concentrations of Gd-DTPA, diluted in a 10:1 water-yogurt mixture, MR PC measurements were correlated with a Doppler guide wire as gold standard., Results: MR PC measurements correlated well with the Doppler derived data (r=0.99; P<0.01; maximum pre-stenotic velocity: 21.6+/-0.5 cm/s; maximum intra-stenotic velocity: 81.7+/-0.6 cm/s). Following Gd-DTPA administration no significant (P>0.05; Student's t-test) flow measurement changes were noted (maximum pre-stenotic velocity: 21.3+/-1.3 cm/s; maximum intra-stenotic velocity: 84.0+/-3.6 cm/s). However, delineation of the perfused lumen was enhanced after the application of Gd-DTPA., Discussions and Conclusion: The application of Gd-DTPA does not affect MR PC velocimetry. However, the application of contrast media allowed a more accurate vessel segmentation. MR PC measurements can be reliably carried out after application of Gd-DTPA.