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Purpose: To determine the best radiographic landmark for the cavoatrial junction (CAJ) using electrocardiographic-gated, 64-row multidetector coronary computed tomographic angiography (CTA)., Materials and Methods: Institutional Review Board approval was obtained. Patient age, sex, weight, and height were recorded. The CAJ was localized by 2 readers using multiplanar CTA, cross-referenced with a scout topogram. Designated radiographic landmarks (the carina, intersection between the bronchus intermedius and the right heart border, and the inflection of the right heart border) were assessed for visibility and vertical distance from the CAJ., Results: Sixty consecutive CTA studies (39 men, 21 women; age range, 27 to 98 y; mean±SD, 55±15 y) were analyzed. The closest radiographic landmark to the CAJ was the intersection between the bronchus intermedius and the right heart border (0.9±0.8 cm above the CAJ), visible in 71% of patients. The second closest radiographic landmark was the inflection of the right heart border (1±0.8 cm above the CAJ), visible in 84% of patients. The carina was visible on 100% of topograms, 4.2±1.1 cm above the CAJ. There was no strong correlation between age, weight, height, or sex and the visibility or distance of landmarks from the CAJ., Conclusions: The intersection of the bronchus intermedius with the right heart border and the inflection of the right heart border are the closest radiographic landmarks to the CAJ. When these landmarks are not identifiable, the most uniformly visible radiographic landmark is the carina.

We describe a fetus at 36 weeks with long QT syndrome presenting with variable types of atrioventricular blocks, ventricular premature beats, and torsades de pointes. All these diagnoses were made with the superior vena cava-aorta Doppler approach and confirmed with postnatal electrocardiography., (Copyright © 2012 Mosby, Inc. All rights reserved.)

Intravenous leiomyomatosis is a rare tumor arising either from a uterine leiomyoma or from uterine vessel walls with extension into venous channels. Although intravenous leiomyomatosis is considered histologically "benign," intrusion to the cardiac chambers is almost malignant given its possibility for destruction of heart valves, extending into the pulmonary vasculature, and embolizing. We report a patient with an intravenous leiomyomatosis progressing through the left iliac vein, along the entire vena cava up to the right cardiac chambers and branches of pulmonary artery (PA), and review the literature on this subject., (© 2012 Wiley Periodicals, Inc.)

Background/purpose: Our aim was to perform a macroscopic and imaging (ultrasonographic and angiographic) evaluation of vascular closure stapler (VCS) metallic clips for renal transplantation in growing piglets to assess their role for transplantation surgery in young children. If these techniques are to be useful, it is necessary to prove that their use avoids one of the main pitfalls of conventional sutures in this setting, namely lack of growth in the suture line., Methods: Twenty-four piglets were used for this study. Animals were subjected to a heterotopic renal autotransplantation when they were 45 days old. The right kidney was moved from its normal location to the cranial area of the iliac fossa. The end-to-side anastomoses between the renal artery and vein and the aorta and vena cava, respectively, were performed using VCS metallic clips in 6 animals. Continuous polypropylene suturing was used in another 6 piglets, and continuous polyglycolic acid suture was used in 6 additional piglets. A control group of 6 animals without renal autotransplantation was also included in the study. All animals were allowed to grow for 6 months, during which time serial angiographic and ultrasonographic studies were carried out to assess the existence of vascular flow disturbances or stenosis. Similarly, angiographic measurements were obtained to document growth at the anastomotic site. Longitudinal growth was evaluated postmortem after the 6-month growing period., Results: Angiography showed significant (P < .001) transverse growth in both arteries and veins belonging to the VCS clips, running absorbable suture, or control groups. No significant difference was observed among the 3 groups. Vascular growth in the running nonabsorbable suture (polypropylene) group, however, was significantly less than in the other 3 groups and did not significantly differ from baseline. Baseline luminal diameters at the anastomotic site as measured by angiography in the VCS group were 3.64 ± 0.40 mm in the artery and 5.30 ± 1.43 mm in the vein. After growth, these values increased to 6.87 ± 0.90 mm and 11.27 ± 2.53 mm, respectively. Significant longitudinal growth was evidenced macroscopically after 6 months in both aorta and vena cava in all groups. On the other hand, significant longitudinal growth in the renal artery and vein were only observed in the control, VCS, and absorbable suture groups., Conclusions: In this experimental setting, satisfactory macroscopic and angiographic vascular growth results were obtained using the VCS clips, suggesting that this suture could be the technique of choice in pediatric transplantation surgery., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Study Design: Prospective study., Objective: To describe a midline anterior approach to the lumbar spine from the right side, below the aortic bifurcation to L5-S1, and by mobilizing the vena cava from right to left between L2 and L5. Feasibility and complication rate related to the approach have been studied., Summary of Background Data: Midline anterior approach to the lumbar spine has developed during these last years, mainly for interbody fusion and disc arthroplasty surgery. This retroperitoneal approach is well described in publications and classically made from the left side. Major complications associated with the approach are known: retrograde ejaculation, venous injuries, and arterial thrombosis., Methods: A total of 469 patients were included in a prospective study between August 2003 and November 2010, either for interbody fusion by anterior approach or for total disc replacement, on one or several levels between L2-L3 and L5-S1., Results: On the 154 patients who had a mobilization of the vena cava, no injury occurred. Only 4 major venous injuries occurred. There was no arterial complication, and the oxygen saturation signal was interrupted in only 1 case. No case of retrograde ejaculation was found., Conclusion: The midline anterior retroperitoneal approach from the right side is a safe alternative compared with the classical approach from the left side. The low rate of venous injury is explained by the sidewall thickness of the vena cava compared with the left iliac vein sidewall. Contrary to what happens by left-sided approach, the vascular retraction required for access to L4-L5 and above does not lead to arterial occlusion and therefore diminishes the risk in atheromatous patients. The absence of retrograde ejaculation confirms previous studies conducted on the left anastomosis of the superior hypogastric plexus, suggesting that its approach and mobilization by the left side are delicate.

The objective was to evaluate blood flow in fetal and maternal vessels by Triplex Doppler and its association with development of blood vessels during gestation in the domestic cat. Ten queens were examined weekly from 14 to 63 d after mating. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI) of uteroplacental, aorta and umbilical fetal arteries and caudal vena cava of the fetus were evaluated. Throughout pregnancy, there was an increase in PSV and EDV in the aorta and umbilical arteries. In the caudal vena cava, there was an increase in PSV, whereas the EDV was constant, with a significant increase on Day 63. Peak systolic velocity and EDV of the uteroplacental artery reduced significantly on Day 63. Resistance index of the umbilical artery progressively decreased. In the aorta, this reduction was detected only on Day 42, with no defined pattern in the caudal vena cava and uteroplacental artery. Pulsatility index of the aorta varied. Although pulsatility increased in the caudal vena cava on Day 35 and remained elevated, pulsatility was significantly reduced in the umbilical artery by Day 63. The pulsatility index of the uteroplacental artery was constant (increased only on Day 63). Triplex Doppler evaluation could be a useful adjunct for prenatal care of pregnant queens, including assessment of vascular gestational development and prediction of gestational age., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Bicaval dual lumen catheters improve the efficiency of veno-venous extracorporeal membrane oxygenation by minimizing recirculation with an innovative design, which requires precise placement of three catheter ports in the superior vena cava, right atrium, and inferior vena cava, respectively. However, the exact position of these catheter ports is usually not known during placement because they cannot be visualized with conventional radiography. We performed a retrospective review of our experience over the past year using transthoracic echocardiography to evaluate the position of the catheter ports. From a subcostal, sagittal imaging approach, we were able to identify all three catheter ports in 11 of 11 studies. At least one of the catheter ports was incorrectly positioned in 5 of 11 studies. Further prospective evaluation is necessary to determine if catheter repositioning based on transthoracic echocardiography findings can further improve the clinical efficiency of veno-venous extracorporeal membrane oxygenation., (Copyright © 2012 Wiley Periodicals, Inc.)

The aim of this study was to evaluate the measurement of the total splanchnic blood flow (SBF) using a clinical diagnostic method based on Fick's principle and hepatic extraction of 99mTc-mebrofenin (99mTc-MBF) compared with a paraaminohippuric acid (pAH) dilution method in a porcine model. Another aim was to investigate whether enterohepatic cycling of 99mTc-MBF affected the SBF measurement. Five indwelling catheters were placed in each pig (n = 15) in the portal, mesenteric, and hepatic veins, as well as in the aorta and the vena cava. The SBF was measured using both methods. The portal blood flow; the intestinal and hepatic oxygen uptake; the net fluxes of oxygen, lactate, and glucose; and the extraction fraction (EF) of 99mTc-MBF were measured before and for 70 min after feeding. The mean baseline SBF was 2,961 ml/min vs. 2,762 ml/min measured by pAH and 99mTc-MBF, respectively, and increased significantly to 3,977 ml/min and 3,981 ml/min postprandially. The hepatic EF of 99mTc-MBF decreased from 40% at the start of the investigation to 16% 70 min after feeding. The arterial-portal difference in 99mTc-MBF concentration was 0.21% (P = 0.48), indicating no intestinal extraction or metabolism. The clinical method for measuring the SBF based on hepatic 99mTc-MBF extraction is robust compared with the indicator dilution method, despite the decrease seen in hepatic extraction of 99mTc-MBF. Because there was no difference in the content of 99mTc-MBF between the arterial and portal vein plasma, the SBF can be calculated from an arterial and a hepatic vein sample.

Objective: To construct reference ranges of ductus venosus (DV) Doppler indices in normal singleton pregnancies., Methods: A cross-sectional study was conducted on low-risk singleton pregnancies with accurate gestational age, and normal fetuses were enrolled into the study. Measurements of DV Doppler indices were determined by experienced sonographers. Poor quality images were excluded., Results: A total of 640 fetuses underwent DV measurements, ranging from 13 to 30 for each gestational week. The relationship between gestational age and DV Doppler indices was not linear. The best-fit regression equations are as follows: preload index = (5.061 - 0.4882) × exp (-0.211 × GA) + 0.4882; peak velocity index for veins = (7.498 - 0.5609) × exp (-0.2184 × GA) + 0.5609; pulsatility index for veins = (17.9 - 0.6053) × exp (-0.2512 × GA) + 0.6053; systolic/atrial wave ratio = (300 - 2.124) × exp (-0.3649 × GA) + 2.124. Notably, during the period from 14 to 20 weeks' gestation, all of the four indices rapidly decreased and they were relatively stable or slightly decreased after that. The nomogram tables for various percentile ranges were constructed., Conclusion: A nomogram for DV Doppler indices for each gestational week during the period from 14 to 40 weeks' gestation was established. These reference ranges may be a useful non-invasive tool for evaluation of fetal cardiac function., (Copyright © 2011 S. Karger AG, Basel.)

Recently, model-based methods for the automatic segmentation of the heart chambers have been proposed. An important application of these methods is the characterization of the heart function. Heart models are, however, increasingly used for interventional guidance making it necessary to also extract the attached great vessels. It is, for instance, important to extract the left atrium and the proximal part of the pulmonary veins to support guidance of ablation procedures for atrial fibrillation treatment. For cardiac resynchronization therapy, a heart model including the coronary sinus is needed. We present a heart model comprising the four heart chambers and the attached great vessels. By assigning individual linear transformations to the heart chambers and to short tubular segments building the great vessels, variable sizes of the heart chambers and bending of the vessels can be described in a consistent way. A configurable algorithmic framework that we call adaptation engine matches the heart model automatically to cardiac CT angiography images in a multi-stage process. First, the heart is detected using a Generalized Hough Transformation. Subsequently, the heart chambers are adapted. This stage uses parametric as well as deformable mesh adaptation techniques. In the final stage, segments of the large vascular structures are successively activated and adapted. To optimize the computational performance, the adaptation engine can vary the mesh resolution and freeze already adapted mesh parts. The data used for validation were independent from the data used for model-building. Ground truth segmentations were generated for 37 CT data sets reconstructed at several cardiac phases from 17 patients. Segmentation errors were assessed for anatomical sub-structures resulting in a mean surface-to-surface error ranging 0.50-0.82mm for the heart chambers and 0.60-1.32mm for the parts of the great vessels visible in the images., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Objective: To quantitatively and qualitatively assess the radiographic appearance of the thorax of clinically normal alpaca crias., Animals: 21 clinically normal alpaca crias., Procedures: Left-right lateral (LR), right-left lateral (RL), dorsoventral (DV), and ventrodorsal (VD) projections of the thorax were acquired. To account for differences in cria size, measurements of thoracic structures were compared with other anatomic landmarks., Results: Mean ± SD vertebral heart scale was 9.36 ± 0.65 for LR projections, 9.36 ± 0.59 for RL projections, 8.21 ± 0.51 for DV projections, and 8.65 ± 0.57 for VD projections. Dimensions of the heart were compared with the length of the T3 through T5 vertebral bodies, third to fifth rib distance, and thoracic height and width, which provided additional methods of cardiac evaluation. For RL projections, mean ratio of the right cranial pulmonary artery diameter to the third rib width was 0.41 ± 0.10 and mean ratio of the right cranial pulmonary vein to the third rib width was 0.44 ± 0.10. Caudal lobar pulmonary vessels and the caudal vena cava were difficult to quantitatively assess on DV or VD projections. On lateral projections, the trachea was increased in diameter at the origin of the right cranial lobar bronchus. No qualitative differences were found between LR and RL radiographs. The lungs were generally better inflated on VD projections, with more separation of the heart and diaphragm., Conclusions and Clinical Relevance: Establishment of radiographic values for alpaca crias should prove useful in assessment of thoracic disease in this species.

Background: Iliocaval venous obstruction (ICVO) can be a significant contributor to venous hypertension in patients with advanced disease. The incidence of ICVO in patients with CEAP clinical class 5 and 6 disease has not been reported. In this study, we reviewed a series of patients with healed or active venous leg ulcers to determine the incidence of ICVO and the risk factors related to its occurrence., Methods: Patients with CEAP clinical class 5 and 6 venous insufficiency underwent evaluation with duplex ultrasound scan to identify the presence of venous reflux in the deep and superficial systems and either computed tomography (CT) or magnetic resonance (MR) venography to identify ICVO. The venograms were evaluated by two separate examiners to calculate the percentage of obstruction in the iliocaval outflow tract. Demographics and risk factors related to venous disease were collected and examined for their association with severe ICVO., Results: A total of 78 CEAP clinical class 5 and 6 patients evaluated with either a CT or MR venogram were retrospectively reviewed. The average patient age was 59.3 years and 53.4% were men. The ulcer affected the left lower extremity in 46% of cases and 50% of patients reported a medical history of deep vein thrombosis (DVT). Overall, 37% of imaging studies demonstrated ICVO of at least 50% and 23% had obstruction of >80%. Risk factors that were found to be independently associated with a significantly higher incidence of >80% ICVO included female gender (P = .023), a medical history of DVT (P = .035), and reflux in the deep venous system (P = .035). No limb with superficial venous reflux (SVR) alone was found to have ICVO >80%., Conclusions: ICVO is a frequent and underappreciated contributor to venous hypertension in patients with venous leg ulcers. Women and patients with a history of DVT or duplex scan-diagnosed deep venous reflux (DVR) have a higher incidence of outflow obstruction and should be routinely studied with CT or MR venography to allow correction in this high-risk group of patients., (Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: To characterize the localization, visible extent (ie, measurement of selected dimensions), and appearance of the liver, caudal vena cava, portal vein, and gallbladder during ultrasonography in healthy goats., Animals: 27 female Saanen goats., Procedures: A 5.0-MHz linear transducer was used to ultrasonographically examine the localization, visible extent of various dimensions, and appearance of the liver, caudal vena cava, portal vein, and gallbladder from the right side of each goat., Results: Images of the liver were obtained in all goats. The dorsal margin of the liver extended in a cranioventral to caudodorsal direction parallel to the caudal margin of the lungs. The greatest visible extent of the liver was evident at the seventh and eighth intercostal spaces (mean value, 15.9 cm), and width was evident at the 10th intercostal space (mean value, 5.2 cm). The caudal vena cava had a triangular shape on cross section; the maximum width in cross section, circumference, and surface area ranged from 1.2 to 1.8 cm, 4.8 to 5.2 cm, and 0.8 to 1.1 cm², respectively. The portal vein was round on cross section (diameter, 0.8 to 1.7 cm) with stellate ramifications into the liver parenchyma. The gallbladder was pear-shaped and variable in size; it extended beyond the ventral margin of the liver to a variable degree depending on the amount of bile., Conclusions and Clinical Relevance: Results provided information regarding the ultrasonographic appearance of the liver, caudal vena cava, portal vein, and gallbladder in healthy goats; these data may be useful during examination of goats with suspected liver disease.

We describe the use of ultrasonography-guided percutaneous splenic injection of agitated saline and heparinized blood for the diagnosis of portosystemic shunts (PSS) in 34 dogs. Agitated saline mixed with 1 ml of heparinized autologous blood was injected into the spleen of 34 sedated dogs under sonographic guidance. The transducer was then sequentially repositioned to visualize the portal vein, the caudal vena cava, and the right atrium through different acoustic windows. It was possible to differentiate between intrahepatic and extrahepatic shunts depending on the entry point of the microbubbles into the caudal vena cava. Portoazygos shunts and portocaval shunts could be differentiated based on the presence of microbubbles in the caudal vena cava and/or the right atrium. In one dog, collateral circulation due to portal hypertension was identified. In dogs with a single extrahepatic shunt, the microbubbles helped identify the shunting vessel. The technique was also used postoperatively to assess the efficacy of shunt closure. All abnormal vessels were confirmed by exploratory laparotomy or with ultrasonographic identification of the shunting vessel. Ultrasound-guided transsplenic injection of agitated saline with heparinized blood should be considered as a valuable technique for the diagnosis of PSS; it is easy to perform, safe, and the results are easily reproducible.

Purpose: To evaluate low-dose contrast-enhanced magnetic resonance angiography (CE-MRA) at high temporal and spatial resolution for imaging of abdominal vascular structures., Materials and Methods: Contrast-enhanced magnetic resonance angiography (TWIST [time-resolved angiography with interleaved stochastic trajectories]) was performed in 8 male New Zealand white rabbits at 3 T using a prototype 32-channel coil. Gadoteridol (Gd-HP-DO3A, ProHance; Bracco Imaging SpA, Milan, Italy) and the high-relaxivity agent gadobenate dimeglumine (Gd-BOPTA, MultiHance; Bracco Imaging SpA), each at a dose of 0.04 mmol/kg body weight, were used in an intraindividual comparison. Quantitative analysis of contrast-to-noise ratio (CNR) was performed in regions of interest placed in the aorta and the adjacent tissues. The image quality in the aorta, external iliac artery, and vena cava was categorized by 2 independent blinded readers from excellent (1) to poor (3)., Results: A significantly (P < 0.001) higher CNR was obtained with gadobenate dimeglumine. The improved CNR led to a better delineation of the external iliac arteries. Qualitative rating showed the image quality to be excellent for gadobenate dimeglumine and adequate for gadoteridol., Conclusions: Time-resolved CE-MRA performed at 3 T with a 32-channel volume coil can be improved using the high-relaxivity agent gadobenate dimeglumine, which increases quality and quantity of vessel enhancement.

Aortocaval fistula (ACF) is a rare complication of abdominal aortic aneurysm (AAA). We report the endovascular repair of an AAA rupture into the inferior vena cava. A 78-year-old woman was admitted to our hospital for acute hypotension. She presented with a pulsatile abdominal mass and became rapidly anuric. Abdominal computed tomography (CT) showed an AAA rupture into the inferior vena cava. The features of the AAA made it suitable for endovascular repair. To prevent pulmonary embolism caused by the presence of sac thrombosis near the vena cava lumen, a temporary vena cava filter was deployed before the procedure. A bifurcated stent-graft was placed with the patient under local anaesthesia, and the AAA was successfully treated. A transient type II endoleak was detected on CT 3 days after endograft placement. At routine follow-up 6 and 12 months after the procedure, the patient was in good clinical condition, and the type II endoleak had sealed completely. Endovascular treatment offers an attractive therapeutic alternative to open repair in case of ACF; however, only small numbers of patients have been treated, and long-term follow-up interval is lacking.

Determination of central venous pressure (CVP) is relevant to patients with right heart disease, hypovolemia, and following intravenous fluid therapy. We hypothesized that changes in CVP in dogs could be predicted by measurements of hepatic vein diameter, caudal vena cava (CVC) diameter, and hepatic venous flow velocities. Nine healthy American Foxhounds were anesthetized. Following baseline recordings, intravenous fluids were administered to increase CVP. Volume administration created treatment periods with CVP ranges of 5, 10, 15, 20, and 25 mm Hg. Flow velocities in the right medial hepatic vein were recorded using pulsed wave Doppler ultrasound. Hepatic vein, CVC, and aorta diameters were determined with B-mode ultrasound. Variables were compared across the treatment periods by ANOVA for repeated measures. Relationships between CVP, Doppler, and B-mode variables were evaluated using Spearman's rank correlations, multiple linear regression, and repeated measures linear regression. The a-, S- and v-wave velocities were augmented significantly with volume loading. The best part (semipartial) correlation coefficients predicting increasing CVP were identified with v-wave velocity (0.823), S-wave velocity (-0.800), CVC diameter (0.855), and hepatic vein diameter (0.815). Multiple linear regression indicated that CVP in this study could be predicted best by a combination of CVC and hepatic vein diameter and the v-wave velocity (r = 0.928). Ultrasound imaging identified gallbladder and pancreatic edema consistently, likely related to acute volume loading. These findings may be applicable in the assessment of volume status, dogs with right heart disease, and during serial monitoring of dogs receiving fluid or diuretic therapy.

The aim of this work was to evaluate the hemodynamic changes in the utero-placental arterial vessels in rabbits (Orictolagus cuniculus) throughout pregnancy as well as those in the umbilical cord, aorta, and caudal vena cava of fetuses to establish their normal reference ranges for systolic peak velocity (SPV), end diastolic velocity (EDV), pulsatility index (PI), and resistance index (RI). The blood flow waveforms were monitored every 4 d in 10 rabbits from Day 10 of pregnancy onward by means of color and pulsed wave Doppler ultrasonography using a 5.5-7.5 MHz microconvex transabdominal probe. The utero-placental blood flow was characterized by steep increases and decrease in the SPV with a slow diastolic wave and relatively high EDV, whereas that of the umbilical artery was discontinuous until Day 22 of pregnancy, when a diastolic waveform was also detectable. From Day 10 to 22 of pregnancy, the fetal aorta blood flow was discontinuous, but thereafter a diastolic peak was measurable. The blood flow of the fetal caudal vena cava was characterized by a systolic peak followed by a small diastolic peak. Throughout the gestation, the SPV and the EDV of maternal and fetal vessels increased (alpha<0.05), whereas the PI and the RI decreased (alpha<0.05), except for the utero-placental vessels. This work confirms that the rabbit could also be a valid experimental animal model to study, by Doppler ultrasonography, functional hemodynamic changes of the fetuses and placenta vessels in both normal and pathophysiologic conditions., (2010 Elsevier Inc. All rights reserved.)

Retrocaval ureter and transposition of the caudal vena cava are each, rare developmental anomalies. We describe the usefulness of static fluid magnetic resonance urography and dynamic contrast-enhanced magnetic resonance urography in the diagnosis of these anomalies. Basic techniques, benefits, and drawbacks of magnetic resonance urography are presented.

Objective: Swelling of an extremity may be a sign of peripheral deep venous thrombosis but may occasionally be due to more proximal or central venous obstruction. Venous Doppler sonography of the extremities is a commonly performed procedure to evaluate for the presence of deep venous thrombosis. Pulsed-wave Doppler sonography is performed as part of this procedure to evaluate for the presence of cardiac pulsatility or respiratory phasicity. The importance of information provided by the pulsed-wave Doppler waveform must not be undervalued. Thus, the purpose of this article is to discuss the pathology of the thorax, abdomen, and pelvis that can be discovered by identifying abnormal waveforms in the veins of the extremities., Conclusion: Abnormal waveforms provide information for compression or obstruction of the proximal venous system in the thorax, abdomen, and pelvis. When these waveforms are abnormal, previous imaging should be reviewed or additional imaging performed to discover the cause.

Background: Chronic venous insufficiency (CVI) in the obese, often with severe clinical manifestations, is increasingly encountered in clinical practice. The association has drawn special interest as the pathophysiology may be different from that seen in the non-obese. The disease poses special management problems in the obese as traditional conservative measures are seldom effective. Iliac-caval venous stenting has been effective in CVI management but applicability in the obese raises concerns regarding stent compression, morbidity and efficacy., Methods: Results of iliac-caval stenting in 101 limbs of 87 patients are presented. Clinical features, venous test results, and outcome after stenting are reported with comparison to select relevant features in the non-obese limbs (n = 1513) that were stented over the same 11 year period., Results: Bilateral clinical manifestations CVI were twice as common in the obese subset compared with the non-obese (28% vs 14% respectively, P = .0007), the incidence increasing with BMI. Resting and exercise femoral vein pressures were similar to the non-obese. Obstructive lesions of primary or postthrombotic origin similar to those seen in non-obese limbs were detected by intravascular ultrasound examination in 89% of limbs. Compression by increased intra-abdominal pressure associated with obesity was likely the mechanism of obstruction in 11% of the limbs. Iliac-caval venous stenting was found to be safe with no mortality (<30 days), low morbidity (deep venous thrombosis in 3%), high patency (86% cumulative at five years), and satisfactory clinical outcome. Sixty-eight percent and 46% of limbs showed cumulative improvement in pain and swelling respectively at 5 1/2 years after stenting, with 65% and 31% limbs achieving complete relief of these respective symptoms. Thirty of 45 limbs (58% cumulative) were free of dermatitis/ulcer at four years., Conclusion: The mechanism of venous obstruction in the obese is substantially similar to those in the non-obese. Primary or post-thrombotic lesions as seen in non-obese CVI cases are present in 89% of cases per IVUS examination. Compression of the venous outflow by adiposity/abdominal pressure may be a factor in 11%. Iliac-caval venous stenting is a satisfactory clinical option in the obese with severe CVI manifestations requiring speedy relief.

The management of intravascular metallic foreign bodies (FB) can be difficult and challenging. We report a case of a migrating FB, initially within the femoral vein which subsequently migrated to the intrahepatic vena-cava. Following a change of posture, the metallic FB moved with gravity against the normal venous blood flow to the left renal vein. It was finally fixed in position in a peripheral branch of the renal vein using an intravascular stent. Employing gravity as a therapeutic intervention and the technique used in isolating the FB has not, to our knowledge, been reported before. A case is described, and the literature is reviewed.

This report describes a simple venous reconstructive technique that results in an autogenous vascular graft with sufficient luminal diameter for replacing the vena cava. The majority of vena caval reconstructions are performed using prosthetic grafts; however, graft infection is a concern in clean-contaminated hepatobiliary and retroperitoneal resections.

We investigated the potential utility of transoesophageal echocardiography (TOE) in facilitating central venous catheter (CVC) insertion in patients undergoing cardiac surgery. Thirty five patients undergoing elective cardiac surgery and CVC insertion were prospectively included in the observational, single-centre clinical investigation. Following induction of general anaesthesia and tracheal intubation, the TOE probe was inserted and the bicaval view obtained prior to CVC insertion (site at discretion of the anaesthesiologist). Prospectively collected data included site and sequence of CVC insertion attempts, information regarding ease of guidewire insertion, whether or not guidewire was visualized via TOE, and other pertinent information. In 1 patient, the TOE bicaval view could not be readily obtained because of right atrial (RA) distortion. In 31 patients, the TOE bicaval view was obtained and CVC access was successful at the site of first choice (guidewire visualized in all). Three patients had noteworthy CVC insertions. In one, CVC insertion was difficult despite visualization ofguidewire in the RA. In another, multiple guidewire insertions met with substantial resistance and without visualization of guidewire in the RA. One patient was found to have an unanticipated large mobile superior vena cava thrombus that extended into the RA, which changed clinical management by prompting initial CVC insertion into the femoral vein (potentially avoiding morbidity associated with thrombus dislodgement). Our prospective observational clinical study indicates that routine use of TOE during CVC insertion may help avoid potential complications associated with this intervention. If both CVC insertion and TOE are going to be used in the same patient, the benefits of TOE should be maximized by routine visualization of the bicaval view during guidewire insertion.

Early or multiple cardiac catheterizations may result in occlusion of the femoral veins prohibiting their use. The internal jugular or sub-clavian approach may be an appropriate alternative. However, these approaches may not be suitable in patients with surgical interruption of the superior vena cava. In other patients, they may not allow easy access to certain areas of the heart. The transhepatic approach is an important alternative route for performing cardiac catheterization and interventions. Depending on the planned procedure, it may be the preferred route to perform the cardiac catheterization even in the presence of patent femoral veins. The indications, technical details and potential complications of this approach are discussed., ((c) 2006 Wiley-Liss, Inc.)

To show the effects of different concentrations of contrast agent on signal time curves and image contrast of abdominal aorta, vena cava and portal vein in comparison to each other as well as liver and spleen. Imaging was carried out in a 1.0 Tesla clinical scanner. Sixty patients were prospectively included and divided into three contrast agent (Gd-DTPA) dosage groups (0.1 mmol/kg, 0.2 mmol/kg and 0.3 mmol/kg). All patients were scanned using a time-resolved 3D FLASH sequence (58 phases) with a 3.75 second acquisition time per phase. Signal time curves and image contrast levels were evaluated. No significant differences were found for the maximum signal enhancement between the groups in the investigated vessels. Image masking, the subtraction of the baseline images, resulted in a substantial improvement in image contrast. However, statistically significant differences between the contrast agent dosage groups could only be found for vena cava and liver. Vessel conspicuity is not significantly improved with an increase of contrast agent dose. However, an increase in contrast agent dosage increases vessel contrast. Our findings suggest that a single dose single station investigation seems to be sufficient for high quality abdominal MRA.

The results of radiation diagnostic techniques were analyzed in 29 patients with aortic aneurysmal ruptures with formation of aortic anastomoses. The examination and treatment of 362 patients with abdominal aortic aneurysmal ruptures revealed that 23 (6.35%) patients had anastomoses (aortocaval (n = 15), aortoduodenal (n = 6), aortogastric (n = 1), and aortoureteral (n = 1)). Six patients were observed to have secondary aortointestinal anastomoses occurring after reconstructive vascular surgery. In one patient, abdominal aortic aneurysmal rupture first led to the formation of a primary aortoduodenal anastomosis and some time after surgery a secondary aortointestinal fistula emerged. One out of 113 patients with aortic dissecting aortic aneurysms had an aortopulmonary fistula. Ultrasonography, computed tomography, and angiography were performed in 27, 19, and 14 patients, respectively. Radiation diagnostic techniques revealed fistulas in 9 (31%) out of the 29 patients. The diagnosis of aortic anastomoses presents challenges.

Background: After the insertion of a central venous catheter, a chest radiograph is usually obtained to ensure correct positioning of the catheter tip., Objective: To determine in a paediatric population whether B-mode and colour Doppler sonography after central venous access is useful to evaluate catheter position, thus obviating the need for a postprocedural radiograph., Materials and Methods: A prospective study of 107 consecutive central venous access procedures placed in a paediatric intensive care unit was performed. At the end of the procedure, B-mode and colour Doppler sonography were used to assess catheter position and check for complications. A postprocedural chest radiograph was obtained in all patients., Results: In 96 patients postprocedural B-mode and colour Doppler sonography showed colour Doppler signals within the vena cava. Among the 11 patients predicted to have a potential complication, there was one pneumothorax and ten malpositions. Chest radiography showed a total of 13 complications-1 pneumothorax and 12 malpositions. The concordance between colour Doppler sonography and chest radiography was 98.1% in the detection of catheter position; sonography had a sensitivity of 84.6% and a specificity of 100%., Conclusions: The close concordance between B-mode and colour Doppler sonography and chest radiography justifies the more frequent use of sonography to evaluate catheter position because ionizing radiation is eliminated. Chest radiography may then be performed only when there is suspected inappropriate catheter tip position after sonography.

To quantify the radiographic parameters of the caudal vena cava (CVC) in healthy cattle and demonstrate their clinical usefulness, the present study compared the ratios of the diameter of the thoracic CVC to the diameter of the aorta (Ao) and length of the thoracic vertebrae (VL), which are all positioned in the same intercostal space, in 81 healthy control cattle (43 growing, 38 adult) and 10 cattle with heart disease. The average diameter of the CVC (CVCave) was correlated with the size of the Ao and VL in the control cows. Although the diameter and pulsation index of the CVC differed significantly between the growing and adult cows, the ratios of CVC/Ao and CVC/VL were fixed values for both the growing and mature cattle. However, in the cattle with heart disease, the pulsation index of the CVC was significantly lower or there was absence of pulsation due to a dilated CVC, and the ratio of CVCave/Ao and CVCave/VL were significantly higher than those in the healthy cattle.

Coronary artery fistulae are abnormal communications between a coronary artery and a cardiac chamber or major vessel (vena cava, pulmonary veins, pulmonary artery). They are usually diagnosed by coronary arteriography. Clinical presentations are variable depending on the type of fistula, shunt volume, site of the shunt, and presence of other cardiac conditions. In this article, we review the literature regarding etiology, incidence, clinical manifestation, image studies, and management.

Objective: We sought to investigate feasibility of vasa vasorum imaging using the novel technique of contrast harmonic intravascular ultrasound., Methods: Prototype intravascular ultrasound (IVUS) instrumentation was developed for the sensitive detection of micro-bubble contrast agents. The technique, "harmonic" imaging, involves transmitting ultrasound at 20 MHz (fundamental) and detecting contrast signals at 40 MHz (second harmonic). Phantom experiments were conducted to investigate the detection of a small vessel in the wall surrounding a larger vessel. In vivo experiments were conducted in atherosclerotic rabbit abdominal aortas., Results: The phantom experiments showed improved small vessel detection in harmonic mode relative to fundamental mode. For the in vivo experiments, harmonic imaging enabled the visualization of contrast agent outside the aortic lumen through a statistically significant (P < 0.001) enhancement of image power, consistent with the detection of adventitial microvessels. These microvessels were not detected in fundamental imaging mode., Conclusions: These results indicate the feasibility of contrast harmonic intravascular ultrasound as a new technique for vasa vasorum imaging.

Background and Purpose: To study the relations of major blood vessels (aortoiliac bifurcation and iliocaval confluence) and the inferior epigastric arteries to the umbilicus and the anterior superior iliac spine (ASIS) planes and to apply this information to define ideal, anatomically based locations for primary and secondary laparoscopic port insertions to minimize vascular injuries., Materials and Methods: Two hundred randomly selected postcontrast CT images of the abdomen and pelvis were assessed by two radiologists. The position of the umbilicus (mobile point), ASIS (fixed point), and relations with the great vessels were measured. The angle of the umbilicus with the aortic bifurcation, theta (theta), was calculated using trigonometric principles. The position and course of the inferior epigastric arteries (IEA) was analyzed in 103 patients with color Doppler ultrasonography., Results: The median distance of the aortoiliac bifurcation was 8 mm (interquartile range [IQR] 28.8 mm] and that of the iliocaval venous confluence 25 mm (IQR 32 mm) below the umbilicus. The aorta divided 48 mm (IQR 16 mm) and the iliac veins joined 33 mm (IQR 9 mm) above the ASIS plane. The angle of the umbilicus to the aortoiliac bifurcation in the sagittal plane had a range of 14 degrees to 34 degrees with a median of 21.6 degrees . The median distance from the right IEA to the midline at the umbilicus was 4.75 cm (IQR 0.7 cm), and the same distance in the ASIS plane was 4.8 cm (IQR 0.7 cm). The distance of the IEA to the midline did not exceed 6 cm in any patient on either side or in either plane., Conclusion: The position of the umbilicus should not be relied on for access planning. The relation between the level of the ASIS and the aortic bifurcation is more consistent. The ideal primary port entry (or Veress needle site) is at the ASIS plane in the midline, and the ideal lateral port entry is in the same plane >6 cm from the midline. If the umbilicus is to be used, a Hasson insertion is desirable, but if a Veress needle is used at the umbilicus, an angle of 45 degrees in the sagittal plane should be used.

Objectives: To assess the effect of different radiographic projections on thoracic width, as well as position and visibility of the trachea, principal bronchi, cardiac silhouette, aorta, caudal vena cava (CVC) and oesophagus., Methods: Right lateral recumbency (RLR), left lateral recumbency (LLR), dorsoventral (DV) and ventrodorsal (VD) thoracic radiographs of 42 dogs were reviewed retrospectively., Results: In 78 per cent of cases the thoracic width was significantly larger on the VD projection than on the DV projection. The angle of divergence formed by the principal bronchi was significantly larger on the VD projection than on the DV projection in 80 per cent of dogs. A cardiac silhouette bulge at 1 to 2 o'clock was apparent on the VD projection in 22 per cent of dogs but was never seen on DV projections. The descending aorta was more visible at the 4 to 5 o'clock cardiac silhouette level on the DV projection and laterally at the T8 level on LLR projections. The CVC was better seen on VD and LLR projections. The oesophagus was visible as a soft tissue opacity in LLR in large dogs with normal thoracic conformation in 35 per cent of cases., Clinical Significance: The DV projection appears to be more reliable for assessing the cardiac silhouette, the descending aorta and the angle of divergence of the principal bronchi. The VD projection should be considered for evaluating the CVC. LLR should be used for assessing the descending aorta and CVC.

Significant spontaneous thrombus disintegration in deep venous thrombosis (DVT) occurs very infrequently. On the contrary, these thrombi are prone to appositional growth and migration into the pulmonary arteries. The development of chronic venous insufficiency due to postthrombotic syndrome is a frequent consequence of DVT. Therapeutic options in DVT include anticoagulation and recanalising procedures such as thrombolysis and thrombectomy. After appropriate indication assessment, the interventional radiologist can offer an efficacy-proven minimally-invasive vessel restitution approach by performing locoregional thrombolysis, pharmacomechanical therapy or, particularly in iliocaval thrombosis, mechanical thrombectomy. These methods not only serve to restitute of vessel patency, but also allow preserving venous valve function. In DVT with recurrent pulmonary embolism, retrievable filters with extended implantation duration can be deployed. In chronic proximal venous flow obstruction or in case of significant residual stenosis after thrombolysis, balloon angioplasty with stent implantation is the treatment modality of choice. Consequently, the radiologist can adopt an important role in the treatment of extensive venous disease. In this article, the treatment modalities concerning iliofemoral and iliocaval thrombosis are demonstrated and illustrated.

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by a combination of arterial or venous thrombosis and recurrent fetal loss, accompanied by elevated titers of antiphospholipid antibodies (aPL). APS has been recognized as the leading cause of vascular thrombosis in children. The diagnostic and therapeutic approach to APS in childhood may be different from that for adults and because of the rarity of aPL-related thrombosis in children, the natural history and optimal management of APS can be defined only through large, multicenter, controlled studies.

Radio-isotopic techniques may be useful in diagnosis and staging of chronic diffuse liver diseases. Liver angioscintigraphy (LAS) and per-rectal portal scintigraphy (PRPS) are at well discriminating portal hypertension (PHT), very early cirrhosis hemodynamic failure and compensatory arterialisation of liver perfusion. Supplied information is related to PHT, liver morphology and mesenchimal activity in liver, spleen and bone marrow. Correlation of LAS and PRPS may diagnose installing of PHT earlier than any actual morphologic imagistic method. Our experience (after more than 300 PRPS and 500 LAS) suggests that PHT and portal-cave shunts (PCS) may be classified in five functional stages. These five patterns (types) are characteristic for portal dynamics, supporting disease staging and follow-up of evolution to cirrhosis. All five dynamics may be assessed by PRPS and LAS. Scintigraphic techniques also explore portal thromboses, perfusion differences between the lobes of cirrhotic liver, betablockers effect in PHT, earliest stages of PHT, malignant tumours occurring on cirrhosis, the different characteristics of alcoholic liver comparing to viral etiology.

The value of ultrasonography was evaluated in 85 dogs and 17 cats presented with a clinically suspected portosystemic shunt (PSS). A PSS was confirmed in 50 dogs and nine cats (single congenital extrahepatic in 42, single congenital intrahepatic in 11, and multiple acquired in six). Six dogs and one cat had hepatic microvascular dysplasia, and 29 dogs and seven cats had a normal portal system. Ultrasonography was 92% sensitive, 98% specific, and had positive and negative predictive values of 98% and 89%, respectively, in identifying PSS, with an overall accuracy of 95%. When a PSS was identified with ultrasonography, extrahepatic, intrahepatic, and multiple acquired PSS could be correctly differentiated in 53/54 patients (98%). The combination of a small liver, large kidneys, and uroliths had positive and negative predictive values of 100% and 51% for the presence of a congenital PSS in dogs. The portal vein/aorta (PV/Ao) and portal vein/caudal vena cava (PV/ CVC) ratios were smaller in animals with extrahepatic PSSs compared with animals with microvascular dysplasia, intrahepatic PSSs and those without portal venous anomalies (P<0.001). All dogs and cats with a PV/Ao ratio of < or = 0.65 had an extrahepatic PSS or idiopathic noncirrhotic portal hypertension. Dogs and cats with PV/Ao and PV/CVC ratios of > or = 0.8 and > or = 0.75, respectively, did not have an extrahepatic PSS. Reduced or reversed portal flow was seen in four of four patients with multiple acquired PSSs secondary to portal hypertension. The presence of turbulence in the caudal vena cava of dogs had positive and negative predictive values of 91% and 84%, respectively, for the presence of any PSS terminating into that vein.

Background: Cavotricuspid isthmus (CTI) characteristics are rarely documented when comparing catheters in radiofrequency ablation (RFA) of atrial flutter (AFL). Our objectives were (1) to evaluate the impact of CTI morphology and length on ablation procedures and (2) to compare the efficacy of an 8-mm-tip catheter with an irrigated cooled-tip RFA in the subgroup presumed to be more difficult to treat (with a long CTI, >35 mm)., Methods and Results: Over a period of 17 months, 185 patients accepted the protocol and underwent an isthmogram in preparation for RFA. Groups were classified according to CTI length and CTI morphology. RFA was performed with an 8-mm-tip catheter for patients with a short CTI, < or =35 mm (n=123), whereas randomization between an 8-mm-tip and a cooled-tip catheter applied to patients with a longer CTI, >35 mm (n=62). For long CTI, 32 patients were assigned to an 8-mm catheter and 30 patients to the cooled-tip RFA ablation group. In this subset, RF application (18.2+/-17 versus 19+/-13 minutes) and x-ray exposure (20.8+/-18 versus 18+/-13 minutes) did not differ between the 8-mm-tip and the cooled-tip procedures. Number of applications (9.9+/-11 versus 18.6+/-15 minutes; P<0.0001) and x-ray exposure (11.7+/-11 versus 19.5+/-16 minutes, P=0.0001) differed significantly between patients with short and long CTIs. Patients with short and straight CTIs required 3 times fewer RFA applications and shorter x-ray exposure compared with other CTI morphologies (pouch-like recesses and concave characteristics)., Conclusions: The number of RF applications required for a complete isthmus block in long CTIs is not influenced by the choice between an 8-mm or cooled-tip catheter. Procedure parameters, however, are significantly influenced by CTI length and morphology. Pouch-like recesses and concave characteristics account for much longer ablation times at all CTI lengths.

We report a 67-year-old man with highly symptomatic polycystic liver disease. Fenestration was selected to treat symptoms because the cysts were scattered diffusely and the normal liver volume was limited. Although this patient was relieved from symptoms of liver cysts consequently, several severe postoperative complications including disseminated intravascular coagulation, respiratory failure, liver failure, and biliary leakage occurred resulting in a 6-month postoperative hospital stay. Although various treatments for symptomatic adult polycystic liver disease have been advocated, a definitive treatment remains controversial, especially in diffuse adult polycystic liver disease. Fenestration is one of the alternative treatments for the patients whose cysts are difficult to resect. However high morbidity rate should be carefully assessed, if extensive fenestration is needed to treat diffuse adult polycystic liver disease. Further consideration of appropriate treatments for diffuse adult polycystic liver disease is needed.