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PURPOSE Accurate artery-vein separation on pulmonary computed tomographic (CT) angiography is desirable for preoperative 3-dimensional image simulation, while using a minimal amount of contrast medium. This study aimed to verify whether a split-bolus contrast enhancement protocol with test-bolus tracking would provide contrast differentiation between the pulmonary arteries (PA) and pulmonary veins (PV) during high-pitch single-pass CT angiography. MATERIALS AND METHODS Fifty patients underwent pulmonary CT angiography with a triphasic split-bolus injection protocol with the main bolus of contrast medium for 6 seconds, followed by a subsequent bolus of 20% diluted contrast medium/80% saline for another 6 seconds and a 5-second saline chaser. The single-scan timing was individually tailored to the peak enhancement at the left atrium, that is, the pulmonary-venous dominant phase, by monitoring a time-enhancement curve with test bolus. RESULTS Time-enhancement curves of the test bolus demonstrated that the interval times between the peak enhancements at the PA and PV were ~6 seconds. For contrast enhancement image analyses with our protocol, the attenuation measurements at the main PA and left atrium were performed. The mean (SD) CT numbers were 246.4 (50.0) HU at the main PA, and 410.8 (59.0) HU at the left atrium. The mean difference in the CT numbers was 164.4 HU (95% confidence interval: 149.2-179.6, P

To evaluate the feasibility of High-resolution (HR) magnetic resonance imaging (MRI) of the liver using deep learning reconstruction (DLR) based on a deep learning denoising technique compared with standard-resolution (SR) imaging.This retrospective study included patients who underwent abdominal MRI including both HR imaging using DLR and SR imaging between April 1 and August 31, 2019. DLR was applied to all HR images using 12 different strength levels of noise reduction to determine the optimal denoised level for HR images. The mean signal-to-noise ratio (SNR) was then compared between the original HR images without DLR and the optimal denoised HR images with DLR and SR images. The mean image noise, sharpness and overall image quality were also compared. Statistical analyses were performed with the Friedman and Dunn-Bonferroni post-hoc test.In total, 49 patients were analyzed (median age, 71 years; 25 women). In quantitative analysis, the mean SNRs on the original HR images without DLR were significantly lower than those on the SR images in all sequences (p 0.01). Conversely, the mean SNRs on optimal denoised HR images were significantly higher than those on the SR images in all sequences (p 0.01). In the qualitative analysis, the mean scores for the image noise and overall image quality were significantly higher on optimal denoised HR images than on the SR images in all sequences (p 0.01) except for the mean image noise score in in-phase (IP) images.The use of a deep learning-based noise reduction technique substantially and successfully improved the SNR and image quality in HR imaging of the liver. Denoised HR imaging using the DLR technique appears feasible for use in liver MR examinations compared with SR imaging.

Background Postpartum dyspnea is commonly observed, but its cause is often unknown. Purpose To investigate postpartum dyspnea, we compared lung iodine mapping (LIM) using dual-energy computed tomography (DECT) between postpartum women and women suspected of having pulmonary thromboembolism (PTE). Material and Methods In this retrospective study, 109 women of reproductive age (50 postpartum women, 59 women unrelated to pregnancy) underwent DECT between March 2009 and August 2020. Among the postpartum women, 23 patients were excluded due to late-onset dyspnea (n=20: >48 h after delivery) or the presence of PTE (n=3). A total of 86 patients were divided into three groups (27 postpartum women [postpartum group], 19 women with PTE [PTE group], and 40 women without PTE [non-PTE group]). Quantitation was applied to a decreased LIM value (LIM5; defined as 5 to whole LIM volume (%LIM5). LIM defects were classified into five patterns (0 = none, 1 = wedge-shaped, 2 = reticular/liner, 3 = diffuse granular/patchy, 4 = massive defects) based on a consensus between two readers. Results There were significant differences in the LIM5 and %LIM5 values among the three groups. The LIM5 and %LIM5 were largest in the PTE group, and postpartum women showed intermediate values between the non-PTE and PTE groups. Wedge-shaped defects were prominent in the PTE group, and diffuse granular/patchy defect was a typical feature in the postpartum group. Conclusion Postpartum women with dyspnea showed granular/patchy defects on DECT with a median quantitative value between the PTE and non-PTE groups.

To compare the occurrence of transient respiratory motion artifacts (TRMAs) in multiple arterial phases on abdominal magnetic resonance (MR) images between those obtained using gadobutrol and gadoxetate disodium. Two hundred and fourteen abdominal MR examinations (101 with gadoxetate disodium, 113 with gadobutrol) were evaluated. Dynamic three-dimensional contrast-enhanced T1-weighted imaging (CAIPIRINHA-Dixon-TWIST-VIBE) including single-breath-hold six arterial phase acquisitions was performed on a 3.0-T MRI scanner. The TRMAs frequency and the mean TRMA scores were compared between patients assessed with gadoxetate disodium and those assessed with gadobutrol. In addition, the timing of TRMAs appearing for the first time was also recorded and compared between the two groups. The mean TRMA scores in all arterial phases using gadoxetate disodium were significantly worse than in those using gadobutrol (1.49 ± 0.78 vs. 1.18 ± 0.53, P

There is wide agreement that morphologic features and enhancement kinetics should be evaluated for MRI of the breast, although there has been no clear consensus concerning optimal temporal resolutions. The objective of this study was to investigate the optimal temporal resolution for the kinetic analysis of breast cancers.Thirty-four patients with 34 enhancing lesions of breast cancer who underwent dynamic contrast-enhanced MRI (DCE-MRI) on a 3.0-T scanner were included in this retrospective study. DCE-MRI was performed with an original temporal resolution of 10-s, and the values of pharmacokinetic parameters (Ktrans, Ve, Kep, and area under the curve (AUC)) were compared with selected data of 30-s and 60-s time intervals.Among the 34 lesions, 10 showed a wash out pattern, 16 showed a plateau pattern, and 8 showed a persistent enhancement pattern. The Ktrans value in the wash-out pattern was significantly higher than that of other time-intensity curve patterns (p 0.01). The Kep and AUC also showed significant differences between the wash-out pattern and other types (p 0.01). On comparing the perfusion parameters among different temporal resolutions, simulations showed that only the AUC differed significantly between the data acquired at a 10-s temporal resolution and that acquired at a 60-s time interval (p 0.01). Although the comparison of the AUC between the 30-s and 60-s data also showed significant differences (p = 0.01), there was no significant difference between the 10-s and 30-s data (p = 0.17).DCE-MRI with a temporal resolution of 30-s preserves the kinetic information. Further prospective studies will be needed to investigate the trade-off between temporal and spatial resolution in DCE-MRI.

Objective: Major liver resection is an effective treatment option for patients with liver malignancy. The future liver remnant (FLR) volume and complications after portal vein embolization (PVE) were compared between the ipsilateral right portal vein (PTPE) and transileocolic (TIPE) approaches. Methods: A total of 42 patients (TIPE, n = 22; PTPE, n = 20) underwent right lobectomy after PVE. CT and hepatobiliary scintigraphy were repeated before and after PVE. The blood examination findings and the FLR values (FLRCT: calculated from CT, %FLRCT: FLRCT ratio, %FLRSPECT: FLR ratio using single photon emission CT, FLRCT/BS: FLRCT to body surface ratio) were compared between two approach sites. The complications and mortality were also analyzed after PVE and major right hepatectomy. Results: There were no significant differences in the patient characteristics, blood examination findings or FLR values between two groups. Adequate liver regeneration was observed without significant differences between PTPE and TIPE (increased ratio of FLRCT: 8.7% vs 19.2%, p = 0.15 [25–75 percentile: 17.1–60.4], %FLRCT: 11.2% vs 8.3%, p = 0.25 [6.3–13.3], %FLRSPECT: 15.4% vs 19.2%, p = 0.09 [16.0–22.4], FLRCT/BS: 33.6% vs 47.1%, p = 0.19 [17.2–60.4], respectively), but TIPE required a significantly longer procedure time than PTPE [181.4 min vs 108.7 min, p < 0.01 (103.3–193.5)]. However, one patient was converted to TIPE due to bleeding during PTPE. After right lobectomy, portal vein stenosis or thrombosis was noted in three patients [two with TIPE (9.1%) and one with PTPE (5%)] and three TIPE patients died within 90 days (13.6%) after right hepatectomy. Conclusion: FLR volume significantly increased after PVE, regardless of the approach sites; however, PTPE is a useful technique with a shorter procedure time.

To determine imaging findings of pancreatic adenocarcinomas incidentally detected on contrast-enhanced multiphasic dynamic computed tomography (CT) obtained during the follow-up for other diseases. From January 2007 to December 2018, 14 patients with pancreatic adenocarcinomas incidentally detected on CT obtained during the follow-up for other diseases (incidental group) and 105 patients with pancreatic adenocarcinomas symptomatically detected on ultrasound or CT (non-incidental group) were included. Imaging characteristics of the tumor were compared between the two groups. Additionally, imaging findings prior to the detection of a tumor on previous CT images in the incidental group were also assessed. In cancers of the pancreas body/tail, there was a significantly smaller tumor size (median, 17 mm vs. 42 mm, p

To determine the consistency of major hepatocellular carcinoma (HCC) features between CT and MRI based on Liver Imaging Reporting and Data System (LI-RADS) v2018 and to investigate the additional value on gadoxetic acid-enhanced MRI.Patients who underwent dynamic CT and gadoxetic acid-enhanced MRI within 1 month were investigated. Two radiologists evaluated the presence of major HCC features and categorized observations using LI-RADS v2018 algorithm. In addition, each observation was recorded as hyper-, iso-, or hypo-intensity on hepatobiliary-phase (HBP) images.Sixty-one patients with 110 observations were identified. Among 88 observations classified as LR-3, 4 or 5, arterial phase hyper-enhancement and washout appearance showed higher frequencies on CT than on MRI (75.0% vs. 58.0%, P 0.001, and 60.2% vs. 44.3%, P = 0.014, respectively). Of the 59 LR-3 observations categorized on MRI, 70.0% of observations with hypo-intensity on HBP images were HCCs, whereas 89.5% of observations with iso- or hyper-intensity on HBP images were non-HCCs (P 0.001) CONCLUSION: The frequencies of arterial phase hyper-enhancement and washout appearances were higher on CT than on gadoxetic acid-enhanced MRI. For LR-3 observations, adding the hepatobiliary-phase hypo-intensity to major features improved the diagnostic performance of MRI in distinguishing HCCs from non-HCC lesions.

An image-display application for medical liquid-crystal display (LCD) monitors called the sharpness recovery (SR) function has been developed to compensate for image sharpness as a function of deficiencies in the modulation transfer function (MTF) of a monitor. We investigated the effects of the SR function for a five-megapixel (MP) mammography LCD monitor on the resolution and noise properties of the displayed images by measuring the MTF and overall noise power spectrum (NPS), respectively. Furthermore, the effectiveness of the SR function for the 5-MP monitor in displaying subtle microcalcifications on digital mammograms was verified using a two-alternative-forced-choice sensitivity measurement as an initial application for medical image interpretation. Four radiologists compared the visibility of 45 regions of interest with a malignant microcalcification cluster shown on SR-processed and unprocessed mammograms. SR processing improved the MTF of the displayed images by approximately 40% at the Nyquist frequency of the 5-MP monitor, whereas it slightly increased the overall NPS values. All observers indicated that the fraction of cases considered to have better visibility of microcalcifications with the SR processing was significantly greater than that without the processing (averaging 82%, with the 95% confidence interval ranging from 70 to 93%). The SR processing for the 5-MP monitor yielded a significant improvement in the resolution properties of the displayed images, with a certain increase in the image noise. The SR function has the potential to improve the observer performance of radiologists, particularly when reading subtle microcalcifications reproduced on 5-MP monitors.

Although it is important to quantify the degree of fatty degeneration of the pancreas, it is difficult to make such a quantification using conventional computed tomography (CT). The present study evaluated the feasibility of pancreatic fat quantification by dual-energy CT (DECT) compared with T2*-corrected six-point Dixon magnetic resonance imaging (MRI). Twenty-eight patients who underwent both DECT (100 and 150 kVp) and Dixon MRI without the use of contrast agents were analyzed. The region of interest (ROI) was placed at the head and body/tail of the pancreas on fat volume fraction (FVF) maps generated using the multi-material decomposition (MMD) algorithm on DECT. The FVF (%) of pancreatic parenchyma measured by DECT (CT-FVF) was compared with that measured on FVF maps calculated using Dixon MRI (MR-FVF) using the Spearman rank correlation coefficient. The median CT-FVF (%) values of the head and body/tail of the pancreas on DECT were 14.2% (range 0.1–81.2%) and 9.4% (range 0–40.8%), respectively. The median MR-FVF (%) values of the head and body/tail of the pancreas on Dixon MRI were 12.2% (range 1.2–80.9%) and 8.1% (range 0.3–43.7%), respectively. CT-FVF (%) measured by DECT showed a significant correlation with the MR-FVF (%) measured by Dixon MRI in the head of the pancreas (ρ = 0.631, P

To compare the image quality of multiphasic (arterial, portal, and equilibrium phases) dynamic computed tomography (CT) of the abdomen obtained by a low tube voltage (70kVp) in combination with a half-dose iodine load using low-concentration contrast agent in high tube output dual-source CT with a standard tube voltage (120kVp) and full-dose iodine load using the same group of adult patients. Fifty-five patients who underwent both low-tube-voltage (70kVp) abdominal CT with a half-dose iodine load and standard-tube-voltage (120kVp) CT with a full-dose iodine load were analyzed. The mean CT values and signal-to-noise ratio (SNR) of the liver, aorta and portal veins were quantitatively assessed. In addition, the contrast enhancement of the abdominal organs and overall image quality were qualitatively evaluated. The mean CT values and SNR of the liver parenchyma were significantly higher in 70-kVp protocol than in 120-kVp protocol in all 3 phases (p = 0.018 ~

Purpose To investigate the clinical value of measuring the ECV fraction of the pancreas by DECT in association with an impaired glucose tolerance (IGT) estimated by the hemoglobin A1C (HbA1C) value in patients with or without cirrhosis. Materials and Methods This retrospective study included patients who underwent contrast-enhanced dynamic CT with dual-energy mode between March 2018 and February 2019. The ECV fraction of the pancreas was calculated from iodine map images created from equilibrium-phase contrast-enhanced DECT images. The cross-sectional areas of the pancreas were also measured. Results In total, 51 patients were analyzed (median age, 69 years old; 22 women). The ECV fraction of the pancreas showed a significant negative correlation with the HbA1c value in the cirrhotic group (ρ=-0.346, p = 0.048), while there was no significant correlation in the non-cirrhotic group (ρ=-0.086, p = 0.734). In the elevated HbA1C group, the ECV fraction of the pancreas in the cirrhotic patients (median, 0.247; interquartile range [IQR], 0.098) was significantly lower than that in the non-cirrhotic patients (0.332, IQR 0.113) (p = 0.024). In the elevated HbA1C group, the cross-sectional area of the pancreas was significantly larger in the cirrhotic patients than that in the non-cirrhotic patients (median [IQR]; 2945 [904] vs. 1885 [909] mm2, p = 0.019). Conclusion A reduction in the ECV fraction of the pancreas measured by DECT as well as the enlargement of the pancreatic parenchyma was observed in cirrhotic patients with IGT. These findings suggest that the measurement of the pancreatic ECV fraction by DECT may help clarify the pathophysiology of IGT in patients with cirrhosis.

BACKGROUND Little is known about the pattern of isotope accumulation in the heart on 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography in patients with cardiac sarcoidosis (CS) complicated by ventricular aneurysm (VA).Methods and Results:We prospectively enrolled 82 consecutive patients with CS; 54 patients with active CS (presence of abnormal 18F-FDG accumulation in the heart) were subdivided into VA (n=17) and non-VA groups (n=37). Strong 18F-FDG accumulation surrounding the VA and its disappearance in the VA center was observed in all patients with VA, probably because of scar formation at the VA. Peak standardized uptake value was higher around the VA than in the VA center (5.1±2.1 vs. 2.2±0.6, P=0.0003) and the VA center had no 18F-FDG accumulation (VA center: 2.2±0.6 vs. control area: 2.1±0.6, P=0.37). On the other hand, in non-VA patients with LV wall thinning (n=28), 18F-FDG accumulation was significantly high, even in the area of LV wall thinning (LV wall thinning area: 3.1±0.8 vs. control area: 2.0±0.6, P=0.00002). CONCLUSIONS A pattern of strong 18F-FDG accumulation surrounding the VA and its disappearance in the VA center might be characteristic in patients with CS complicated by VA. Careful attention to FDG uptake would further elucidate CS pathophysiology and aid in the early treatment of VA.

Background Steroid therapy, a key therapy for inflammatory, allergic, and immunological disorders, is often associated with steroid myopathy as one of the side effects. Steroid therapy is considered the first-line therapy for myositis; however, there have been no reports strictly comparing the muscle mass in patients with myositis before and after steroid therapy. Thus, it is currently unclear whether steroid therapy for such patients affects muscle volume in addition to muscle strength. We aimed to determine the change in muscle mass after steroid therapy via cross-sectional computed tomography (CT) in patients with myositis. Methods Data from seven patients with myositis and eight controls, who were all treated with high doses of steroids, were assessed before and after steroid therapy. Clinical factors in patients with myositis included serum muscle enzyme levels and muscular strength. The cross-sectional area of skeletal muscle and the low muscle attenuation rate at the level of the caudal end of the third lumbar vertebra were obtained using CT and measured using an image analysis program for all patients. Data were subjected to statistical analysis using several well-established statistical tests. The Wilcoxon signed-rank test was used for comparing paired data for each patient. The Mann-Whitney U test was used to compare sets of data sampled from two groups. The Spearman’s rank correlation coefficient was used for determining the correlations between two variables. Statistical significance was set at p

The purpose of this study was to compare the results of a histogram-based analysis of static and dynamic lung perfused blood volume (LPBV) images.Sixty-five patients (mean age: 61.3 years, 36 male) underwent dynamic and static LPBV for evaluation of pulmonary vascular diseases (n = 11), lung carcinoma (n = 27) or pulmonary thromboembolism (PTE: n = 27). Seven sets of dynamic sequential scans were performed at the pulmonary trunk using dual-energy technique before the static LPBV scan. The image of lung parenchyma that showed the greatest mean attenuation in dynamic series was defined as the peak dynamic LPBV image. The differences and correlations in the mean attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), histogram skewness and histogram kurtosis were evaluated according to the type of disease in static and dynamic LPBV images.Static LPBV images showed significantly larger mean attenuation (Rt:24.2, Lt: 24.2), SNR (Rt:2.31, Lt:2.30), and CNR (Rt:2.40, Lt:2.39), and smaller kurtosis values (Rt:1.06, Lt:0.61) values in comparison to dynamic LPBV images (p 0.001); however, with the exception of kurtosis of the left lung (r = 0.17), these values were well-corrected with that of the dynamic LPBV images in these values (r = 0.4-0.77, p ≤ 0.001) without kurtosis of left lung (r = 0.17) in all patients. The histogram kurtosis of static LPBV image showed a good correlation with that of dynamic LPBV (r = 0.41-0.77, p 0.05), especially in patients with PTE.In patients with PTE, the static LPBV image valueswere well correlated with the peak dynamic LPBV images which demonstrated pulmonary artery-dominant flow.

We present the case of a 63-year-old woman presenting with a huge pelvic and retroperitoneal high flow arteriovenous malformation (AVM) causing high-output heart failure, who was treated with combined therapies, including transarterial embolization with n-butyl cyanoacrylate–iodized oil mixture (NBCA–lip) and coils for the right ovarian, both internal iliac, 3rd and 4th lumber arteries, venous sclerotherapy using coils and ethanolamine oleate (EO) for the right ovarian and both internal iliac veins with balloon-occluded retrograde transvenous obliteration technique, and direct percutaneous sclerotherapy using the NBCA–lip and EO for the large nidus of AVM under outflow control using occlusion balloon catheters.

Factors affecting the improvement in the lung perfused blood volume (LPBV) were evaluated based on the presence of intrapulmonary clots (IPCs) after anti-coagulation therapy using 64-slice dual-energy CT.96 patients exhibiting venous thromboembolism underwent initial and repeated LPBV examinations between December 2008 and July 2014. Fifteen patients were excluded due to pulmonary comorbidities, and a total of 81 patients were included in this study. Acute pulmonary embolism (PE) was diagnosed in 46 of the patients (56.7%). LPBV images were three-dimensionally reconstructed with two threshold ranges: 1-120 HU (V120) and 1-5 HU (V5), and the relative value of V5 per V120 expressed as %V5. These values were subsequently compared with indicators of the severity of PE, such as the D-dimer level, heart rate and CT measurements. This study was approved by the local ethics committee.In patients with IPCs, the D-dimer, V5 and %V5values were significantly larger (p≤0.01) in the initial LPBV, although these differences disappeared in subsequent LPBV after treatment. The right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio and %V5 values were also significantly reduced, whereas the V5 value did not significantly decrease (p=0.07), but V120 value significantly increased (p0.001) after treatment. However, in patients with IPCs the change rate in %V5 [(subsequent-initial)/initial %V5] showed a better correlation with that in V5 (r=0.94, p0.001) rate than that in V120 (r=0.19, p=0.19) after treatment.Increased whole lung perfusion (V120) and a decreased low perfusion volume (V5) affect the improvement in the %V5 values after treatment.

BackgroundSublingual nitroglycerin capsules or spray is routinely used to treat anginal attacks and to maximally dilate the epicardial coronary arteries during coronary angiography. These dilated coronary vessels have an advantage, but increased heart rates were disadvantageous for coronary computed tomography angiography (CTA).PurposeThe influence of applying nitroglycerin was analyzed regarding the coronary diameter, coronary luminal attenuation, evaluable number of coronary segments, heart rate (HR), HR variability, the optimal reconstruction phase, and image scoring of CTA in the same patients using a 64-slice dual-source CT.Methods and subjectsFifty-two patients with atypical chest pain underwent coronary CTA before and after the administration of sublingual nitroglycerin without heart rate control. The coronary diameter and luminal attenuation were measured on short-axial images in each coronary segment. The coronary vasodilation ratios (VRs) were calculated from the coronary diameters at the same location before and after the use of nitroglycerin. The local institutional review board approved this study and written informed consent was obtained from all the patients.ResultsNo significant differences were noted in the HR variability or optimal reconstruction phase, despite an increase in HR after the use of nitroglycerin. Nitroglycerin significantly enlarged the coronary artery diameter, and VRs of each coronary segment ranged from 7.54% to 22.26%. As compared with baseline coronary diameter, VRs of minor segments (16.91%) were significantly larger than those of major segments (11.35%), and the magnitude of VR correlated with the baseline coronary diameter (r=−0.48, p

Background The aim of this study is to evaluate the accuracy of a newly developed quantitative method using 64-multislice computed tomography angiography (CTA) to detect coronary in-stent restenosis (ISR). Methods and results CTA was performed in 45 patients who underwent stent implantation (79 lesions) and the accuracy to diagnose ISR was evaluated by comparing with invasive coronary angiography (ICA). CTA was evaluated both visually and quantitatively using a new stent restenosis index (SRI) utilizing CT densities at proximal and distal artery lumen from the stented region and the correction value depending on the stent diameter. ICA showed 11 ISR (14%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for visual evaluation were 78%, 75%, 35%, 95%, and 76%, respectively. On the other hand, the quantitative evaluation using SRI represents 82%, 93%, 64%, 97%, and 91%, respectively. Conclusions Evaluation of ISR using SRI is superior to the visual estimation of CTA.

Background— Recently, we reported that urinary 8-hydroxy-2′-deoxyguanosine (U-8-OHdG), an oxidative stress marker, reflected inflammatory activity in cardiac sarcoidosis (CS). Here, we investigated whether U-8-OHdG levels were associated with ventricular tachycardia (VT) in patients with CS. Methods and Results— This prospective cohort study enrolled 62 consecutive patients with CS, of whom 36 were diagnosed as having active CS based on abnormal 18 F-flurodeoxyglucose accumulation in the heart on positron-emission tomography/computed tomography. The 36 patients with active CS were subdivided as having CS with sustained VT (CS-VT group; n=18) or CS without sustained VT (CS-nVT group; n=18). Twenty-seven patients diagnosed with idiopathic dilated cardiomyopathy served as heart failure controls. U-8-OHdG, brain natriuretic peptide, cardiac function indices, and immunohistological data from subendomyocardial biopsy samples were compared across groups. Immunohistochemical examination of ventricle biopsy samples revealed that the anti-8-OHdG antibody-positive area of cardiac tissue was significantly greater in CS-VT than in CS-nVT or dilated cardiomyopathy and significantly correlated with U-8-OHdG levels (n=58; R =0.61; P P Conclusions— U-8-OHdG levels are associated with VT in patients with active CS diagnosed by 18 F-flurodeoxyglucose positron-emission tomography, providing additive and relevant information about the arrhythmia substrate.

Background The cutoff value for assessing the severity of acute pulmonary thromboembolism (PTE) using relative volumetric evaluations of dual-energy perfusion computed tomography (DEpCT) is unclear. Purpose To determine the proper cutoff value for determining the severity of PTE using DEpCT volumetry. Material and Methods A total of 185 patients with venous thromboembolism were included in this study, of whom 61 were diagnosed with acute PTE. DEpCT images were three-dimensionally reconstructed at the following attenuation ranges: 1–2 HU (V2), 1–10 HU (V10), and 1–120 HU (V120). The ratios of low perfusion areas associated with each threshold range per V120 were also calculated, and the relative ratios were expressed as %V2 to %V10. These values were compared with factors indicating the severity of PTE, including the pulmonary arterial pressure, heart rate, CT angiographic obstruction index (CTOI), and right/left ventricular diameter ratio (RV/LV). Results The area under the curve (AUC) of %V2 was highest (0.783) among these values (95% confidence interval, 0.710–0.856) based on the presence of IPCs. The %V2 showed moderate correlations with CTOI (r = 0.36, P = 0.005) and RV/LV (r = 0.36, P = 0.004) in the patients with acute PTE. Conclusion Volumetric evaluations of DEpCT images using the lowest attenuation threshold range (1–2 HU) exhibit the best correlation with factors suggesting the severity of acute PTE.

Celiac stenosis may result in a pancreaticoduodenal artery aneurysm (PDAA). Celiac stenosis with a PDAA is rare and treatment guidelines are absent. Here, we report 4 cases of celiac stenosis treated using different methods. Of these, 3 involved PDAAs. The PDAAs were successfully treated with coil embolization. For celiac stenosis, we performed open surgery for decompression in 1 patient, stenting in 2 patients, and bypass grafting in 1 patient. In the patients who underwent stenting, stent-associated thrombosis occurred. PDAAs can be treated with coil embolization; however, treatment of celiac stenosis with the endovascular approach might be difficult.

To evaluate the high-resolution computed tomography (CT) findings of primary lung cancer with cavitation and compare the findings in adenocarcinoma and squamous cell carcinoma.The high-resolution CT findings of tumours with cavitation were retrospectively evaluated in 60 patients. Forty-seven of the lesions were diagnosed as adenocarcinomas; 13 were diagnosed as squamous cell carcinomas. The diameters of the tumour and cavity, the maximum thickness of the cavity wall, shape of the cavity wall, the number of cavities, and the presence of ground-glass opacity, bronchial obstruction, intratumoural bronchiectasis, emphysema, and honeycombing were evaluated. The mechanisms of cavity formation were examined according to the pathological features.The maximum thickness of the cavity wall was significantly greater in squamous cell carcinomas than in adenocarcinomas (p=0.002). Ground-glass opacity and intratumoural bronchiectasis were significantly more common in adenocarcinomas than in squamous cell carcinomas (p0.001 and p=0.040, respectively). Regarding the pathological findings, intratumoural bronchiectasis with or without alveolar wall destruction contributed to a significant difference between adenocarcinoma and squamous cell carcinoma (p0.001; odds ratio [OR], 20.35; 95% confidence interval [CI], 3.87-107.10).The cavity wall tends to be thicker in squamous cell carcinomas than in adenocarcinomas. The presence of ground-glass opacity and intratumoural bronchiectasis is strongly suggestive of adenocarcinoma.

The purpose of this study was to evaluate the image quality (IQ) of dual-source CT (DSCT) versus single-source CT (SSCT). A total of 100 patients underwent 64-section CT coronary angiography (50 DSCT, 50 SSCT). Three observers evaluated the IQ of each coronary segment using a four-point scale (1, excellent; 2, good; 3, fair; 4, no assessment). The IQ of DSCT coronary angiography was compared with SSCT coronary angiography on a per-patient, per-vessel, and per-segment basis using the chi-squared test. The DSCT image quality score (IQS) was significantly lower on a per-patient basis and per-vessel basis for all vessels and on a per-segment basis for some segments (1, 2, 4PD, 4AV, 7, 9, 11, 12, 13) compared with SSCT. The DSCT IQS was significantly lower for certain segments (2, 4PD, 11, 13) with high heart rates (≥70 beats/min). The DSCT IQS was significantly lower for certain segments (1, 2, 3, 4PD, 4AV, 7, 8, 9, 10, 12, 13) with low heart rates (

The effect of computed tomography (CT) density-based, non-uniform photon attenuation correction (AC) on lung perfusion distribution and the clinical significance were evaluated.40 patients with pulmonary emphysema, 32 with pulmonary thromboembolism, 25 with lung cancer and 8 normal controls underwent deep-inspiratory breath-hold (DIBrH) Tc-99m-MAA perfusion SPECT, using a dual-head SPECT system and a respiratory tracking device. Scatter-corrected DIBrH SPECT was automatically co-registered with DIBrH CT. AC of DIBrH SPECT was performed using an attenuation coefficient map of a variable-effective linear coefficient calculated from CT pixel density of the co-registered DIBrH CT. The effect of AC on pulmonary perfusion was evaluated by comparison with uncorrected SPECT.After AC, lung perfusion in normal lungs was increased predominantly at deep lungs near the mediastinum and vertebrae and at the upper-middle lungs, with systematic increases of radioactivity (145 ± 28%) and significant enhancement of physiological gravitational ventral-dorsal gradient (P0.01). Throughout the lung diseases, AC significantly enhanced perfusion defect clarity and heterogeneity (P0.001), without noticeable artifacts. The correlation between perfusion heterogeneity and the lung diffusing capacity for carbon monoxide was significantly improved in patients with emphysema (P0.005).CT density-based, non-uniform AC of DIBrH perfusion SPECT provides better assessment of physiologic or impaired perfusion distributions in normal and lung diseases.

57歳の男性．B型肝硬変・肝細胞癌に対して外来経過観察中，下血に対する精査加療目的で当科に緊急入院した．上部消化管内視鏡検査（EGD）で十二指腸下行脚に静脈瘤が認められたものの活動性出血および血液貯留の所見はなく，下部消化管内視鏡検査・カプセル内視鏡検査・経肛門的ダブルバルーン内視鏡検査においても回腸～結腸内に凝血塊の貯留が認められたのみで出血源の同定には至らなかった．腹部血管造影検査では十二指腸周辺に著明な門脈系-大循環系短絡路の発達が認められ，血管造影下CTで十二指腸下行脚付近に造影剤の血管外漏出が疑われた．直後の緊急EGDにより十二指腸静脈瘤破裂と診断し，内視鏡的静脈瘤結紮術（EVL）にて一次止血に成功した．しかしその２日後に出血性ショックに陥ったため，EVLで止血した上で引き続きバルーン閉塞下逆行性経静脈的塞栓術（B-RTO）を施行して完全止血を得た．十二指腸静脈瘤破裂は非常に稀な難治性消化管出血であるが，今回我々はEVL・B-RTO併用療法で止血し救命し得た症例を経験したので報告する．

PURPOSE Lung perfusion impairment in patients with pulmonary arteriovenous fistula (AVF) was evaluated by automated deep inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images. METHODS Participants were 14 patients with a single (N=6) or multiple nodular AVFs (N=8) diagnosed by contrast-enhanced CT scan and/or pulmonary angiography. After the injection of 185MBq Tc-99m-macroaggregated albumin, a whole-body scan was obtained to quantify an intrapulmonary right-to-left shunt. Subsequently, DIBrH SPECT was obtained using the continuous rotating acquisition mode of a dual-headed SPECT system, which was automatically coregistered with DIBrH CT. The anatomic relationship between AVF and perfusion defects was assessed on the fusion images. RESULTS The whole-body scan depicted systemic organs indicating the presence of an intrapulmonary right-to-left shunt in all the patients. DIBrH SPECT showed 34 perfusion defects in these patients, which were located at the AVF and in the surrounding lungs of the AVF on the fusion images, regardless of the absence of morphologic abnormality on CT in all the patients. These defects were considered to be caused by the 'steal phenomenon' associated with the high and fast pulmonary arterial flow to each AVF, which were more extensive and severe in the multiple AVFs compared with a single AVF (P=0.0012), occasionally extending to the entire lobe with AVF or even to the adjacent lobe. In five patients, the fusion images detected a total of six tiny AVFs with unexpectedly extensive 'steal phenomenon'-induced defects, which had been missed by other radiological imaging techniques. The summed value of the shunt index estimated by the whole-body scan and the lung perfusion defect extent estimated by DIBrH SPECT was significantly correlated with PaO2 in all the patients (P < 0.0001), with a better correlation compared with the shunt index alone. CONCLUSION In addition to the right-to-left shunt, 'steal phenomenon'-induced perfusion defects are common in the surrounding lung of pulmonary nodular AVF and cause hypoxemia. DIBrH SPECT-CT fusion images contribute to the objective evaluation of 'steal phenomenon'-induced lung perfusion impairment in AVF and the detection of tiny, subtle AVFs that may be missed by other radiological imaging techniques.

PURPOSE: Cross-sectional lung ventilation (V)-perfusion (Q) imbalance in primary pulmonary arterial hypertension (PAH) and passive pulmonary hypertension (PH) was characterized by automated V/Q single-photon emission computed tomography (SPECT). MATERIALS AND METHODS: Technegas/macro-aggregated albumin SPECT-derived V/Q SPECT and V/Q profile were automatically built to characterize cross-sectional lung V-Q imbalance in 12 patients with primary (idiopathic or familial) PAH and 15 patients with passive PH associated with left ventricular dysfunction or failure. The abnormality of V/Q distribution in these patients was correlated with PaO2 and pulmonary arterial pressure and with lung morphologic changes on computed tomography (CT). RESULTS: Markedly low V/Q ratios (reverse V-Q mismatch) in the background lungs with heterogeneous V/Q distribution was seen in 12 of the 12 (100%) patients with primary PAH and in 10 of the 15 (66%) patients with passive PH, which were predominantly seen in the upper lung zone. Including these regions with reverse V-Q mismatch, the V/Q profile frequently showed flattened peaks with asymmetric and broadened V/Q distribution in all patients, with significant correlation between the standard deviation of V/Q ratios in the entire lungs and PaO2 and mean pulmonary arterial pressure (both; P

Tc-99m-Technegas–MAA single photon emission computed tomography (SPECT)-derived ventilation (V)/perfusion (Q) quotient SPECT was used to assess lung V–Q imbalance in patients with pulmonary emphysema. V/Q quotient SPECT and V/Q profile were automatically built in 38 patients with pulmonary emphysema and 12 controls, and V/Q distribution and V/Q profile parameters were compared. V/Q distribution on V/Q quotient SPECT was correlated with low attenuation areas (LAA) on density-mask computed tomography (CT). Parameters of V/Q profile such as the median, standard deviation (SD), kurtosis and skewness were proposed to objectively evaluate the severity of lung V–Q imbalance. In contrast to uniform V/Q distribution on V/Q quotient SPECT and a sharp peak with symmetrical V/Q distribution on V/Q profile in controls, lung areas showing heterogeneously high or low V/Q and flattened peaks with broadened V/Q distribution were frequently seen in patients with emphysema, including lung areas with only slight LAA. V/Q distribution was also often asymmetric regardless of symmetric LAA. All the proposed parameters of V/Q profile in entire lungs of patients with emphysema showed large variations compared with controls; SD and kurtosis were significantly different from controls (P

Background We investigated whether urinary 8-hydroxy-2′-deoxyguanosine (U-8-OHdG), a marker of oxidative DNA damage, is a prognosticator of cardiovascular-related death in patients with cardiac sarcoidosis (CS). Methods and results In this prospective study, 30 consecutive patients were divided into the active CS (n=20) and non-active CS (n=10) groups, based on abnormal isotope accumulation in the heart on 18 F-fluorodeoxyglucose positron-emission tomography/computed tomography ( 18 F-FDG PET/CT) imaging. Nineteen patients in the active CS group underwent corticosteroid therapy. Before corticosteroid therapy initiation, U-8-OHdG, brain natriuretic peptide (BNP), other biomarkers, and indices of cardiac function were measured. Patients were followed-up for a median of 48months. The primary endpoint was the incidence of cardiovascular-related death. During the follow-up period, in the corticosteroid-treated active CS group, 7 of 19 patients experienced cardiovascular-related death. By contrast, in the non-active CS group, 1 of 10 patients died from cardiovascular-related causes. Univariate and multivariate analyses showed that U-8-OHdG and BNP were independent predictors for cardiovascular-related death. The cut-off values for predicting cardiovascular death in corticosteroid-treated patients with active CS were 19.1ng/mg·Cr and 209pg/mL for U-8-OHdG and BNP, respectively. Patients with a U-8-OHdG concentration ≥19.1ng/mg·Cr or a BNP concentration ≥209pg/mL had a significantly higher cardiovascular-related death risk, but U-8-OHdG had better predictive value compared with BNP. Conclusion These findings suggested that U-8-OHdG was a powerful predictor of cardiovascular-related death in patients with CS, suggesting that active CS patients with elevated U-8-OHdG levels might be resistant to corticosteroid therapy.

To evaluate sentinel lymph node (SLN) mapping with interstitial computed tomographic (CT) lymphography with small volumes of iopamidol for direction of SLN biopsy in breast cancer.Thin-section transverse and three-dimensional CT images that included the breast and axilla were acquired at multi-detector row helical CT in 17 patients with operable breast cancer before subcutaneous injection of 2 mL of undiluted iopamidol into peritumoral and periareolar areas and 1-5 minutes after massage of injection sites. Location and size of SLNs were assessed at CT lymphography and were compared with SLNs at standard axillary lymph node dissection with blue dye staining.CT lymphography allowed localization of SLNs in all patients by means of visualization of a direct connection between an SLN and its afferent lymphatic vessels draining from the injection sites. Afferent vessels were joined and drained into a single axillary SLN, except in four patients with two or three SLNs, including a parasternal one. SLNs did not enhance because of rerouting of lymph flow in four patients. At surgery, SLNs that were stained or not stained with blue dye were easily found with CT lymphographic guidance. Tumoral infiltration was not evident in any resected nodes, except for infiltration in one patient with micrometastasis in SLN alone and infiltration in four patients with massive metastasis in both SLN and distant nodes.Because preoperative CT lymphography-guided SLN mapping provides SLN position with detailed lymphatic anatomy, it may be useful for the direction of breast SLN biopsy.

The usefulness of magnetic resonance imaging (MRI) for aortic diseases is discussed, with special attention given to the MRI features of aortic dissection and Takayasu arteritis. Computed tomography (CT) and MRI provide excellent visualization of vessels and their relationship to surrounding structures; however, CT depicts the vessel lumen optimally only when contrast enhancement is used. MRI, with its inherent multiplanar imaging capability, is well suited for evaluation of the thoracic and abdominal aorta and can be used with or without contrast enhancement. Basic technical considerations in cardiac imaging, which include conventional spin-echo, fast spin-echo, cine gradient, and echo-planar imaging, with time-of-flight and phase-contrast methods, are discussed and applied to aortic aneurysm, aortic dissection, and Takayasu arteritis. The diagnostic capacity of spin-echo MRI in patients with suspected aortic dissection is enhanced when it is combined with cine MRI. Despite the ability of CT and MRI to demonstrate luminal and mural changes of aortic abnormalities, conventional angiography still may be necessary at first admission for selected patients in the late occlusive phase to provide additional information on the degree and extent of the arteritis. CT angiography and MR angiography are promising imaging techniques that will overcome difficulties in visualizing distal branch vessel lesions and obviate the need for conventional angiography in the near future.

Background. Accurate localization of the breast sentinel lymph node (SLN) can be challenging as a minimally invasive approach to the treatment of early-stage breast cancer. We tested the potential capability of interstitial computed tomographic lymphography (CT-LG) using a conventional contrast agent (iopamidol) for SLN mapping. Methods. In 14 female dogs, 0.5 and 1 mL of undiluted iopamidol was injected subcutaneously into the 2 skin areas overlying the mammary gland. Contiguous, 2 mm-thick multidetector helical CT images were obtained through the upper breast and axilla before, and for 60 minutes after, gentle massage at the injection site. Three-dimensional (3D) CT images were obtained from the postcontrast images showing the greatest SLN enhancement. This CT-LG with 2 mL of iopamidol was also evaluated in 5 human female volunteers. Results. The direct connection of SLN and lymphatic vessels draining from the injection sites in the animal models was clearly visualized, even with 0.5 mL of iopamidol. With this dose, the SLN attenuation was maximally enhanced, with a mean of 274 Hounsfield units (HU) on the first postcontrast images. The topographic 3D images provided the comprehensive anatomy of these lymphatic pathways. Of the 28 SLNs and 184 distant nodes visualized on CT images, all of the SLNs (100%) and 161 (87.5%) of the distant nodes could be resected at premortem and/or postmortem, with a good correlation in the locations and sizes with those on the CT images. The CT-LG effectively localized 5 SLNs with averaged maximum attenuation of 223 HU in the human volunteers, without any significant adverse effects. Conclusion. Interstitial CT-LG using small volumes of iopamidol can sufficiently visualize breast lymphatic drainage and may have potential utility for breast SLN mapping. (Surgery 2003;133:170-9.)

RATIONALE AND OBJECTIVES The potential of a noncontrast, electrocardiography (ECG)-gated fast-spin-echo (FSE) MR imaging (MRI) to monitor dynamically altered regional lung perfusion was assessed in acute and temporal pulmonary embolic and airway obstruction dog models. MATERIALS AND METHODS After acquisition of ECG-gated multiphase FSE MR images during one cardiac cycle, the two phase images of the minimal lung signal intensity (SI) during systole and the maximal SI during diastole were acquired in the lower lung levels in six normal dogs, in 13 dogs before and for 35 minutes after temporal microvascular embolization in regional lungs with gradually degradable starch microspheres of spherex, and in 12 dogs before and for 45 minutes after bronchial occlusion with a balloon catheter. In three of the 13 embolic models, the opposite lung areas, however, were permanently embolized with enbucrilate. Subtraction between the diastolic and systolic images yielded a perfusion-weighted image. The results were compared with a gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced dynamic perfusion MRI, which was subsequently performed after the ECG-gated MRI in each animal. RESULTS The multiphase FSE images provided cardiac-dependent pulsatile lung SI changes, and the subtracted perfusion-weighted images provided a uniform perfusion map in normal lungs. In all the embolic models, the subtracted perfusion-weighted images showed gradual disappearance of the spherex-induced perfusion deficits, while the enbucrilate-induced perfusion deficits persistently remained in the three animals. In all airway obstruction models, these images showed gradually decreased perfusion in the hypoventilated areas. These results were consistent with the matched Gd-DTPA-enhanced pulmonary arterial perfusion phase images in each animal. CONCLUSION This noncontrast perfusion MRI may have excellent potential for continuously monitoring dynamically changed regional lung perfusion within a short time on its high spatial resolution cross-sectional images.

Purpose The purpose of this work was to evaluate electron beam CT (EBCT) for the noninvasive assessment of modified Blalock-Taussig (BT) shunt patency in patients with pulmonary atresia. Method Five infants and children with pulmonary atresia and modified BT shunts underwent contrast-enhanced EBCT. Modified BT shunts from the subclavian artery to the pulmonary artery were performed to improve the pulmonary blood flow. Electrocardiogram (ECG)-triggered EBCT was obtained with a 100 ms exposure, 3 mm section thickness, and 2 mm table feed after intravenous administration of contrast material. Three-dimensional (3D) or maximum intensity projection (MIP) EBCT images were compared with conventional angiography. The visibility of modified BT shunts was graded and recorded with use of a four-point scale. Results Satisfactory visualization was achieved in both 3D and MIP EBCT images to evaluate modified BT shunt patency. Conclusion Contrast-enhanced 3D or MIP EBCT imaging with ECG trigger may be used as an effective substitute to evaluate modified BT shunts with low radiation dose exposure.

RATIONALE AND OBJECTIVES: Gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-based aerosol ventilation and perfusion magnetic resonance (MR) images were used to define regional functional impairment in acute airway obstruction (AO) and pulmonary embolic (PE) dog models. METHODS: The aerosol study was performed in 10 anesthetized normal dogs in a supine position during 20-minute spontaneous inhalation of an aerosol of 100- or 200-mmol-Gd/L Gd-DTPA solute produced by an ultrasonic nebulizer in an open-circuit delivery system, combined with a dynamic perfusion study after a 3-second intravenous bolus injection of a 0.1 mmol/kg dose of Gd-DTPA. These MR studies were also performed in the same 10 dogs approximately 30 minutes after obstructing the segmental (n = 6) or lobar (n = 4) bronchus with a balloon catheter, and in another six dogs after segmental (n = 6) and lobar (n = 4) pulmonary arterial embolization with enbucrilate. Regional lung enhancement was assessed on time-signal intensity (SI)-curves and ventilation- and perfusion-weighted images produced by a subtraction technique. RESULTS: The normal lungs were gradually and gravity-dependently enhanced with time after Gd-DTPA aerosol inhalation regardless of the respiratory SI changes, except for three animals with the fastest breathing rate. The averaged maximal relative lung SI increase against the baseline in the successful animals was significantly greater in the slowly and deeply breathing animals than in the fast and shallow breathing animals, regardless of the difference in Gd-concentration (100 mmol Gd/L: 153.3% +/- 69.7% vs. 54.2% +/- 23%; P < 0.001; and 200 mmol Gd/L: 189.7% +/- 68.0% vs. 75.6% +/- 42.2%; P < 0.0001, respectively). There was an additional enhancement of 382% +/- 101 in the ventral lung and 722% +/- 160 in the dorsal lung on the pulmonary arterial phase perfusion image even in the slowly and deeply breathing animals who inhaled 200-mmol-Gd/L aerosol, and the enhancement effect was significantly greater compared with that with the aerosol (P < 0.0001). The ventilation- and perfusion-weighted images clearly defined the regionally matched perfusion-ventilation deficits in all the AO models, and the regionally mismatched perfusion-ventilation in all the PE models. CONCLUSION: Gd-based aerosol can provide efficient lung enhancement in spontaneously and adequately breathing animals, using a relatively noninvasive aerosol delivery system. The combined use of Gd-based perfusion MR imaging may be acceptable for defining regionally impaired function associated with acute AO and PE.

Background Dual-energy perfusion CT (DEpCT) directly represents the iodine distribution in lung parenchyma and low perfusion areas caused by intrapulmonary clots (IPCs) are visualized as low attenuation areas. Purpose To evaluate if volumetric evaluation of DEpCT can be used as a predictor of right heart strain by the presence of IPCs. Material and Methods One hundred and ninety-six patients suspected of having acute pulmonary embolism (PE) underwent DEpCT using a 64-slice dual-source CT. DEpCT images were three-dimensionally reconstructed with four threshold ranges: 1–120 HU (V120), 1–15 HU (V15), 1–10 HU (V10), and 1–5 HU (V5). Each relative ratio per V120 was expressed as the %V15, %V10, and %V5. Volumetric data-sets were compared with D-dimer, pulmonary arterial (PA) pressure, right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio, PA diameter, and PA/aorta (PA/Ao) diameter ratio. The areas under the ROC curves (AUCs) were examined for their relationship to the presence of IPCs. This study was approved by the local ethics committee. Results PA pressure and D-dimer were significantly higher in the patients who had IPCs. In the patients with IPCs, V15, V10, V5, %V15, %V10, and %V5 were also significantly higher than those without IPC ( P ≤ 0.001). %V5 had a better correlation with D-dimer (r = 0.30, P < 0.001) and RV/LV diameter ratio (r = 0.27, P < 0.001), and showed a higher AUC (0.73) than the other CT measurements. Conclusion The volumetric evaluation by DEpCT had a correlation with D-dimer and RV/LV diameter ratio, and the relative ratio of volumetric CT measurements with a lower attenuation threshold might be recommended for the analysis of acute PE.

To evaluate the volumetric values of intrapulmonary clots (IPCs) using 64-section dual-energy perfusion computed tomography (DEpCT).A total of 174 patients suspected of having acute pulmonary embolism (PE) underwent DEpCT, and acute PE was diagnosed in 48 of these patients. DEpCT images were three-dimensionally reconstructed with four threshold ranges: 1-120 HU (V₁₂₀), 1-15 HU (V₁₅), 1-10 HU (V₁₀), and 1-5 HU (V₅). Each relative value per V₁₂₀ was expressed as %V₁₅, %V₁₀ and %V₅. These values were compared with the d-dimer, pulmonary arterial (PA) pressure, right ventricular (RV) diameter, RV/left ventricular diameter ratio, PA diameter, and CT angiographic obstruction index (CTOI).In patients with IPCs, PA pressure, d-dimer and volumetric values of DEpCT were significantly higher (p0.001). Relative volumetric values at DEpCT had better correlations with the PA pressure, PA diameter, and CTOI than absolute ones, and %V₅ especially had good correlations with PA pressure (r = 0.44, p = 0.02), PA diameter (r = 0.40, p = 0.005), and CTOI (r = 0.38, p = 0.009).The relative volumetric evaluation of DEpCT images with a lower attenuation threshold range may be helpful for assessing right heart strain, because these values had good correlation with CTOI, pulmonary pressure, and diameter in suggesting right heart load.

Intrabullous ventilation in patients with pulmonary emphysema (PE) was cross-sectionally evaluated using dynamic xenon-133 gas single photon emission computed tomography (SPECT).Fifty-two patients with PE with a total of 109 bullae of more than 4 cm in maximum diameter underwent xenon-133 gas SPECT. The real xenon-133 gas half-clearance time (T1/2) at each bulla was compared with that at the surrounding lung in the same lobe. The emphysema subtype of the surrounding lung was classified into centrilobular, panlobular, and paraseptal on computed tomography (CT).All bullae except for one in all patients showed xenon-133 gas wash-in. Of the 108 bullae with wash-in, 95 (87.9%) bullae in 46 (88%) patients showed marked xenon-133 gas retention with a T1/2 beyond 110 s (mean: 184 s ± 91). The surrounding lungs of these bullae also showed marked retention with a T1/2 of greater than 100 s (mean: 174 s ± 82), and the majority (N=92, 96.8%) were centrilobular or panlobular on CT. The remaining 13 (12.0%) bullae in six (11%) patients showed minimal retention with a T1/2 of less than 80 s (mean: 62 s ± 11), regardless of no significant difference in size compared with the bullae with marked retention. All the surrounding lungs of these bullae except for one also showed minimal retention with a T1/2 of less than 70 s (mean: 60 s ± 18), which was significantly less compared with that of the bullae with marked retention (P0.0001), and the majority (N=11, 84.6%) were paraseptal with or without an interstitially fibrotic change and predominantly located at the lower lung lobe on CT. The T1/2 of the 108 bullae with xenon-133 gas wash-in was significantly correlated with that of the surrounding lungs (r=0.884, P0.0001).Intrabullous ventilation in patients with PE appears to depend on the ventilation status of the surrounding lung, and bullae with the surrounding lungs of paraseptal-type emphysema tend to show minimal air trapping. Xenon-133 gas SPECT is useful for assessment of the interaction between intrabullous and surrounding lung's ventilation, which is difficult on CT.

Purpose To retrospectively investigate the distribution of the low attenuation area (LAA) on dual energy perfusion CT (DEpCT) in comparison with the results of pulmonary function tests (PFTs) and quantitative CT measurements. Materials and methods Twenty-eight patients (15 male and 13 female; mean age: 62.21 years) underwent DEpCT and PFTs within a 1-month interval. The ranges of the LAA on DEpCT were classified into six groups with attenuation values of 0–3, 0–5, 0–8, 0–10, 0–13 and 0–15HU and the ratios of LAA in each group were compared with the percentage of forced expiratory volume in the 1st second (%FEV 1.0 ), FEV 1.0 /forced vital capacity (FEV 1.0 /FVC) and the relative area of the lung with attenuation coefficients lower than −950HU (RA −950 ). Results The LAAs on the DEpCT images were significantly correlated with the RA −950 , %FEV 1.0 and FEV 1.0 /FVC, and the regression analysis showed that the best values of LAA on DEpCT were 0–10HU with RA −950 ( r =0.63), 0–8HU with %FEV 1.0 ( r =−0.52) and 0–8HU with FEV 1.0 /FVC ( r =−0.61) per patient. Conclusion The iodine disturbance on DEpCT had a moderate correlation with the results of the PFTs and RA −950 , but further examination would be needed for evaluation of iodine distribution.

The purpose of our study was to determine the relationship between the predictive factors and systolic reconstruction (SR) as an optimal reconstruction window in patients with low heart rate (LHR; less than 65 bpm).391 patients (262 male and 129 female, mean age; 67.1±10.1 years of age) underwent coronary CTA without the additional administration of a beta-blocker. Affecting factors for SR were analyzed in age, gender, body weight (BW), diabetes mellitus (DM), coronary arterial disease (CAD), ejection fraction (EF), systolic and diastolic body pressure (BP) and heart rate variability (HRV) during coronary CTA.In 29 (7.4%) of the 391 patients, SR was needed, but there was no apparent characteristic difference between the systolic and diastolic reconstruction groups in terms of gender, age, BW, DM, CAD and EF. In a multivariate analysis, the co-existence of DM [P0.05; OR, 0.27; 95% CI, 0.092-0.80], diastolic BP [P0.01; OR, 0.95; 95% CI, 0.92-0.98] and HRV [P0.01; OR, 0.98; 95% CI, 0.96-0.99] were found to be the factors for SR. In gender-related analysis, HRV was an important factor regardless of sex, but co-existence of DM affected especially for female and BP for male.Especially in the patients with LHR who had a medication of DM, high HRV or high BP, SR, in addition to DR, was needed to obtain high-quality coronary CTA images.