Published papers

Purpose: This study evaluated the feasibility of sheathless access using the combination of a 4-F catheter and a triaxial system for transcatheter arterial chemoembolization (TACE).Materials and Methods: A total of 35 of 53 patients were selected to undergo TACE of hepatocellular carcinoma (HCC) using a triaxial system that included a 4-F shepherd hook catheter, a 2.7-2.9-F high-flow microcatheter, and a 1.7-1.9-F microcatheter without using a sheath introducer. Feasibility was defined as successful completion of the procedure without using another microcatheter or switching to another system. The duration of manual compression after catheter removal was set to 10 minutes. Two hours and 1 hour of bed rest after the procedure were prescribed for 24 and 11 patients, respectively.Results: TACE using a triaxial system without a sheath introducer was feasible in 34/35 cases (97%). A small amount of bleeding around the catheter at the puncture site was observed during the procedure in 3 cases. No other hemorrhagic complications were observed 5 days after the procedure.Conclusion: Sheathless arterial access using the combination of a 4-F catheter and a triaxial system for TACE of HCC was shown to be both feasible and safe. Additionally, using the triaxial system resulted in hemostasis within 1-2 hours of bed rest after catheter removal.

Objectives To compare the image quality between virtual monochromatic spectral (VMS) images obtained using 320-row detector CT and polychromatic 120-kVp images reconstructed with or without iterative reconstruction using various phantom sizes. Materials and methods Torso phantoms simulating three patient sizes and containing four syringes filled with water or different contrast media (5, 10, 15 mgI/mL15 mgI/ml) were used. The phantoms were scanned using dual-energy (80/135-kVp) and single-energy (120-kVp) protocols at different settings (20 mGy, 12 mGy, and 6 mGy). VMS images were generated at 1-keV intervals (range, 35–135 keV). Both the VMS images and the single-energy 120-kVp images were reconstructed using filtered back projection (FBP) and adaptive iterative dose reduction 3D (AIDR-3D). The signal-to-noise ratio (SNR), and the contrast-to-noise ratio (CNR) were assessed. Results Using FBP reconstruction, the SNR and CNR of the VMS images were lower than or similar to those of the 120-kVp images for most dose settings. Using AIDR-3D reconstruction, however, the 70-keV VMS images had higher SNRs and CNRs than the 120-kVp images at most settings. Conclusions The image quality of VMS images with FBP reconstruction tended to be lower than that of the 120-kVp images. With the use of AIDR-3D, however, approximately 70-keV VMS images had a higher image quality than the 120-kVp images.

Angiomyolipoma with epithelial cysts (AMLEC), which has not only a stromal component but an epithelial component, is a rare cystic variant of AML. We present a case of a man in his forties with microscopic hematuria, who had a multilocular cystic tumor in his left kidney. He underwent laparoscopic partial nephrectomy and the tumor was diagnosed as AMLEC histopathologically. We chiefly report the radiologic features of this tumor.

Background: When using 16-slice multidetector-row computed tomography (MDCT) to detect coronary artery stenosis, coronary arteries measuring 1.5 mm or larger in lumen diameter are usually evaluated. The purpose of this study was to investigate the frequency of the visualized lumen in each coronary artery segment measuring more than 1.5 mm in diameter. Methods and Results: Electrocardiographic-gated 16-slice MDCT was used to scan 20 patients after administration of nitroglycerin. The luminal diameter of each coronary artery segment was measured on cross-sectional images using a caliper method. The frequency of the visualized lumen of each coronary artery segment measuring larger than 1.5 mm in diameter was as follows: #1: 100%, #2: 100%, #3: 100%, #4PD:85%, #4AV:80%, #5: 100%, #6: 100%, #7: 100%, #8: 90%, #9: 85%, #10: 40%, #11: 100%, #12: 65%, #13: 100%, #14: 80%. Averaged lumen diameter± standard deviation (mm) larger than 1.5 mm in all patients was calculated as follows: #1: 3.8±0.70, #2: 3.5±0.69, #3: 3.2±0.82, #5: 4.2±1.04, #6: 3.4±0.79, #7: 2.9±0.62, #11: 2.9±0.69, #13: 2.6±0.57. Conclusion: Luminal diameter larger than 1.5 mm of each coronary artery segment can be assessed in most cases by 16-slice MDCT.

Objectives: To review the imaging findings of renal epithelioid angiomyolipomas. Methods: Eight patients treated at two institutions were pathologically diagnosed as having epithelioid angiomyolipoma. All of them underwent computed tomography, and four underwent magnetic resonance imaging. The tumor size, existence of fat, heterogeneity, computed tomography attenuation, degree of enhancement, enhancement pattern and magnetic resonance imaging signal intensity were evaluated. Results: Intratumoral fat was not detected in any of the cases. On unenhanced computed tomography, the intratumoral attenuation was hyperattenuating in six of the seven patients who were examined using this modality. On T2-weighted images, the signal intensity of the solid component, cyst wall or septum was low in three of the four cases. Four of the eight cases were heterogeneous solid-type accompanied by hemorrhage, necrosis or hyalinization. One homogeneous solid-type lesion was large in size and was pathologically accompanied by neither hemorrhage nor necrosis. All three multilocular cystic types were pathologically accompanied by massive hemorrhage in the cystic component. One was accompanied by spontaneous perirenal hematoma. Conclusions: The radiological appearance of most epithelioid angiomyolipomas has a tendency to be hyperattenuating on unenhanced computed tomography images, with low intensities on T2-weighted images. They can be heterogeneously solid, homogeneously solid or a multilocular cystic lesion with massive hemorrhage. © 2013 The Japanese Urological Association.

A 22-year-old woman complained of abdominal discomfort. Ultrasonography, computed tomography, and an endocrinologic work-up revealed a 7-cm nonfunctional tumor at the left adrenal lesion. A transumbilical laparo-endoscopic single-site adrenalectomy was successfully completed in 166 min. The postoperative period was uneventful. The pathologic examination confirmed the solid pseudopapillary tumor occurred in the retroperito-neum. There are only five previous reports of extrapan-creatic solid pseudopapillary tumors. In this case, the tumor was separated from the pancreas and no ectopic pancreas was histologically observed. To the best of our knowledge, this case is the first report of a solid pseudopapillary tumor of the retroperitoneum. © 2011 CARS.

Background: The prevalence of success of percutaneous coronary interventions (PCIs) of chronic total occlusions (CTOs) remains relatively low. We determined the effect of preoperative multidetector computed tomography coronary angiography (CTCA) in PCIs of CTOs. Methods: The study population was 100 consecutive patients who underwent PCIs of CTOs from January 2005 to December 2007 at Keio University School of Medicine. They were divided into two groups according to the absence (non-CT group, n = 60) or presence (CT group, n = 40) of preoperative CTCA. The effect of preoperative CTCA was assessed in the prevalence of success of the procedure, prevalence of complications, irradiation time, and the dose of contrast agents. Results: The prevalence of procedural success was similar in both groups (non-CT group vs CT group 80.0% vs 77.5%, p = 0.76). Irradiation time and the dose of contrast agents were also similar between these groups. The prevalence of complications was significantly reduced in the CT group (23.3% vs 7.5%, p = 0.039), especially coronary perforations, which required treatment only in the non-CT group (10.0% vs 0.0%, p = 0.039). Multiple logistic regression analysis revealed that use of a rotablator (odds ratio [OR]: 4.40, 95% confidence interval [CI]: 1.19-16.27, p = 0.027) and absence of preoperative CTCA (OR: 4.26, 95% CI: 1.04-17.49, p = 0.044) were independent determinants of complications. Conclusion: Preoperative CTCA does not affect the prevalence of procedural success, irradiation time and the dose of contrast agents, but may be useful to reduce the prevalence of complications during PCIs of CTOs. © 2009 Elsevier Ireland Ltd. All rights reserved.

Patients with diastolic heart failure tend to have a poor outcome, similar to that for patients with systolic heart failure. The aim of this study was to explore the ability of MDCT to estimate the left ventricular diastolic function. Thirty patients with suspected coronary artery disease underwent MDCT and echocardiography. The early transmitral flow velocities (E) and the velocity of mitral annulus early diastolic motion (e') were measured in order to evaluate the diastolic function. The scanning delay of CT was determined using a test injection technique. The aortic enhancement was measured over the aortic-root lumen, and it was plotted over time to yield a time-enhancement-curve. A gamma variate function was then fit to the time-enhancement-curve and thereafter both the 'slope' of enhancement for each patient and the region of interest [ROI] were calculated. According to a univariate analysis, the slope of the time-enhancement-curve was found to correlate with the e' (r = 0.686, P = 0.000) and E/e' (r = -0.482, P = 0.007), however, no significant correlation was observed with the systolic parameters of the left ventricle. These results indicate that the slope of the time-enhancement-curve in the aorta significantly correlates with e', i.e. the diastolic parameters, which are independent of the systolic parameters. Based on these findings, we propose that the slope of the time-enhancement-curve may serve as a parameter for the left ventricular diastolic function on MDCT. © 2010 Elsevier Ireland Ltd. All rights reserved.

Multidetector row CT has been established as a noninvasive method for the detection of coronary artery disease. In previous studies, the diagnostic accuracy of 64-slice CT for the detection of in-stent restenosis usually displayed high sensitivity and negative predictive value, while specificity and positive predictive values were too low to allow its utilization in clinical practice. Especially in small stents-with a diameter below 3. 0 mm-the accuracy of CT angiography to detect in stent stenosis has been low. Recently, CT systems with improved in-plane spatial resolution (high-definition CT, HDCT) have become commercially available. Furthermore, an experimental CT (fine-cell detector CT, FDCT) has been developed using half pitch dimension detector cells in both X and Z directions compared with 64-slice CT. Compared with that in conventional 64-slice CT, the spatial resolution was 30% improved in HDCT and 60% improved in FDCT, and the lumen visibility was 1. 3 times improved in HDCT and 1. 5 times improved in FDCT. The diagnostic accuracy of in-stent restenosis with HDCT was higher than 90% in both sensitivity and specificity, moderate (77%) in positive predictive value, and very high (98%) in negative predictive value. FDCT is not yet applicable to patients, however, further improvement of diagnostic accuracy in the evaluation of in-stent restenosis is expected in FDCT. In the near future, cardiac CT could reach the diagnostic performance to replace invasive catheter angiography, and would be the appropriate noninvasive technique for diagnosis of in-stent restenosis. © 2011 Springer Science+Business Media, LLC.

Objectives: To evaluate the diagnostic performance of fast scanning tomosynthesis in comparison with that of chest radiography for the detection of pulmonary nodules, using multidetector-row computed tomography (MDCT) as the reference, and to assess the association of the true-positive fraction (TPF) with the size, CT attenuation value, and location of the nodules. Materials and methods: The institutional review board approved this study, and written informed consent was obtained from all patients. Fifty-seven patients with and 59 without pulmonary nodules underwent chest MDCT, fast scanning tomosynthesis, and radiography. The images of tomosynthesis and radiography were randomly read by 3 blinded radiologists; MDCT served as the reference standard. Free-response receiver-operating characteristic (FROC) and receiver-operating characteristic (ROC) analyses, Cochran-Armitage trend or Fisher exact test, a conditional logistic regression model, and McNemar test were used. Results: Both FROC and ROC analyses revealed significantly better performance (P < 0.01) of fast scanning tomosynthesis than radiography for the detection of pulmonary nodules. For fast scanning tomosynthesis, the average TPF and false-positive rate as determined by FROC analysis were 0.80 and 0.10, respectively. For both fast scanning tomosynthesis and radiography, the average TPF increased with increasing nodule size and CT attenuation values, and was lower for subpleural nodules (all P < 0.01). Conclusions: The diagnostic performance of fast scanning tomosynthesis for the detection of pulmonary nodules was significantly superior to that of radiography. The TPF was affected by the size, CT attenuation value, and location of the nodule, in both fast scanning tomosynthesis and radiography. © 2011 Lippincott Williams & Wilkins.

Background: The coronary sinus (CS) including the great cardiac vein is an important anatomic structure that is considered a landmark for the mitral annulus (MA) and also a target for catheter ablation. Objective: This study evaluated the anatomical relationship between the CS and its surrounding structures visualized by multi-detector computed tomography (MDCT). Methods: We performed MDCT on 42 patients, and the ranges of the coronary arteries (CAs) and esophagus that ran closest (<5 mm) to the CS were examined. In addition, the distances between the CS and the MA and left ventricle and left atrium were compared with the amplitudes of the local atrial and ventricular electrograms in the CS at the most lateral point (3 o'clock) and the inferior point (6 o'clock) in the CS. Results: The distal portion of the right CA ran near the antero-inferior side of the CS ostium in 92% of the patients. The esophagus and the left circumflex CA proximity to the CS ran from 15 to 41 mm and from 53 to 104 mm from the ostium in all patients. At the 3 o'clock and 6 o'clock position of the MA, the distance between the center of the CS and MA was 12 and 13 mm, respectively, and showed negative correlation with the ratio of atrial and ventricular electrograms. Conclusion: The right CA, the left circumflex CA, and the esophagus were frequently located near the CS. The CS was shifted away from the MA, and the CS-MA distance could be predicted with intracardiac electrograms. © 2009 Heart Rhythm Society.

BACKGROUND: Most cases of dementia with Lewy bodies (DLB) show Alzheimer's disease pathology-like senile plaques and neurofibrillary tangles. Several studies have also revealed a high prevalence of positive amyloid imaging with positron emission tomography (PET) in DLB and moderate prevalence in Parkinson's disease (PD) with dementia. However, it remains unclear in PD without dementia as to when the brain β amyloid (Aβ) burden begins and progresses. Our study aimed to determine the prevalence of Aβ deposition in PD without dementia using amyloid PET. METHODS: This was a cross-sectional study on 33 patients with PD without dementia, of whom 21 had normal cognition and 12 met the criteria for PD-mild cognitive impairment. All subjects underwent neuropsychological assessment and [18F] florbetaben (FBB) PET. RESULTS: All subjects had Lewy body-related disorders, displaying a significantly reduced myocardial [123I] metaiodobenzylguanidine uptake. The cortical FBB-binding pattern in all subjects, including APOE e4 carriers, suggested negative Aβ deposition. CONCLUSION: Patients with PD without dementia exhibit an extremely low prevalence of Aβ positivity compared with those reported in cognitively normal elderly controls. Further longitudinal imaging studies and long-term follow-up are needed; however, our findings provide novel insights for understanding Aβ metabolism in PD.

Background and Objective: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are becoming one of the major therapeutic options for the treatment of type 2 diabetes mellitus (T2DM). This study was conducted as an exploratory analysis to clarify the effects of liraglutide, a GLP-1RA, on beta cell function, fat distribution and pancreas volume compared with metformin in Japanese overweight/obese patients with T2DM. Methods: A subpopulation of the Keio study for Initial treatment of type 2 Diabetes with Liraglutide versus Metformin (KIND-LM) study participants (n = 20, 10 in oral metformin group and 10 in subcutaneous liraglutide group) who were enrolled at Keio University Hospital and underwent frequently sampled mixed meal tolerance test (MTT) and abdominal computed tomography (CT) at weeks 0 and 24 were included in this analysis. The patients were treated with either metformin or liraglutide throughout the 24-week study period. Results: Changes in glycemic parameters such as glycated hemoglobulin (HbA1c), glycated albumin and 1,5-anhydroglucitol at week 24 were comparable between the groups. An oral minimal model based on MTT revealed that static-phase beta cell responsiveness (Φs) and static-phase disposition index were significantly increased at week 24 in the liraglutide group but not in the metformin group. There was no significant change in fat distribution as well as body weight at week 24 in either group. Serum amylase and lipase levels modestly but significantly increased in the liraglutide group during the study; however, there was no incidence of pancreatitis and pancreas volume was not changed in the liraglutide group. Conclusion: Liraglutide monotherapy for 24 weeks improved beta cell responsiveness with no change in either body weight or fat distribution. Further investigation is needed to clarify the mechanism by which liraglutide increases serum pancreatic enzymes. Trial Registration: The University Hospital Medical Information Network (UMIN) Clinical Trials Registry (http://www.umin.ac.jp/ctr/); UMIN000004243.

Objective Current imaging techniques for velopharyngeal closure (VPC) evaluation are two-dimensional, static, or distressing, thus necessitating multiple procedures to understand this three-dimensional and dynamic area. We validated the use of a novel four-dimensional (4D) computed tomography (CT) technique for the morphological and kinematic evaluation of VPC in cleft palate patients based on dynamic volume scanning with 320-detector-row CT. Methods Five patients aged 4-10 years (40% males) with persistent velopharyngeal insufficiency post palatoplasty underwent conventional tests (cephalometry and video-nasal endoscopy) and 4D-CT. For each patient, complete multiplanar reconstruction, 4D airway CT, and 4D-CT endoscopy data for all scanning phases were compared with cephalometric and video-nasal endoscopy data. The movements of the velum and posterior pharyngeal walls were graded by each modality. Results 4D airway CT revealed higher anatomical detail than cephalometry, additionally providing dynamic images. 4D-CT endoscopy and video-nasal endoscopy were in agreement for all patients regarding the patterns of VPC, with complete visualization of VPC in five versus one patient, respectively. 4D airway CT and cephalometry showed a discrepancy in one case, wherein grading by cephalometry was overestimated. 4D-CT was also useful in determining the width and length of a proposed pharyngeal flap. The examination time (mean ± standard deviation (SD), seconds), including patient preparation time, was 224 ± 73, 492 ± 145, and 718 ± 123 for cephalometric radiographs, CT, and video-nasal endoscopy, respectively. The mean estimated radiation dose during 4D-CT was 4.44 ± 1.64 mSv. Conclusions 4D-CT provides detailed morphological and kinematic analysis of VPC and may offer advantages over conventional procedures.

© 2019 Elsevier Ltd Radiological evaluation of subarachnoid hemorrhage (SAH) is often subject to interobserver variability. The aim of this study was to retrospectively detect computed tomography (CT) texture parameters in the early postictal state to predict cerebral vasospasm, delayed cerebral ischemia (DCI), and functional outcome in aneurysmal SAH using quantitative CT texture analysis (CTTA) via a commercially available software program and routine CT images. 40 patients with aneurysmal SAH surgically treated at the Keio University Hospital during a four-year period were analyzed. CT texture analyses were performed using a commercially available software program (Synapse Vincent). The following texture parameters of blood clots in the subarachnoid space and cerebral edema were assessed: mean CT value, entropy, skewness, and kurtosis. The mean CT value of blood clots in the subarachnoid space was significantly associated with cerebral vasospasm, DCI, and functional outcome. The mean CT value ≥ 49.64 Hounsfield units (HU) predicted cerebral vasospasm with a sensitivity and specificity of 85.7% and 61.5%, respectively (area under the curve [AUC] = 0.758). The mean CT value ≥ 49.95 HU predicted DCI with a sensitivity and specificity of 100% and 60.6%, respectively (AUC = 0.810). The mean CT value ≥ 53.00 HU predicted poor functional outcome with a sensitivity and specificity of 56.3% and 91.7%, respectively (AUC = 0.747). CTTA using a commercially available software program demonstrated that the mean CT value of clots in the subarachnoid space in the early postictal state could predict vasospasm, DCI, and clinical outcome with a high sensitivity and specificity.

© 2019 Wiley Periodicals, Inc. To evaluate the rotational change in the first metatarsal bone (1MT) of the foot during natural standing using an upright computed tomography (CT) scanner with 320-detector rows. A total of 52 feet of 28 asymptomatic subjects (aged 23–39 years) were evaluated in the natural standing position with or without weight-bearing. A foot pressure plate was used to determine the non-weight-bearing (NWB) or single leg full-weight-bearing (s-FWB) conditions. CT examinations were performed using a noise index of 15 for a slice thickness of 5 mm, rotation speed of 0.5 sec, and slice thickness of 0.5 mm. The rotation of the 1MT was measured on the coronal CT image, which cut the sesamoids' bellies in the frontal slide of the first metatarsal and sesamoids perpendicular to the longitudinal bisection of the third metatarsal, and compared between the weight-bearing conditions. Intra- and inter-observer reliabilities of the rotation angle were also evaluated. The intra- and inter-observer correlation coefficients were 0.961 and 0.934, respectively. The 1MT pronation angle was significantly greater in the s-FWB condition than in the NWB condition (15.2° ± 5.4° vs. 12.5° ± 5.3°, P < 0.01). No sex difference was found in the magnitude of the 1MT pronation angle as a result of weight-bearing. This study first demonstrated that pronation of 1MT occurs due to natural full-weight-bearing in asymptomatic feet. The 1MT's rotational movement under weight-bearing conditions may relate to the onset and pathogenesis of the hallux valgus. Clin. Anat. 32:715–721, 2019. © 2019 Wiley Periodicals, Inc.

© 2020 Wolters Kluwer Health, Inc. All rights reserved. A 66-year-old man with severe diarrhea and severe hypoproteinemia was referred for 99mTc-DTPA-human serum albumin (HSA-D) scintigraphy. The scintigraphy at 24 hours postinjection showed strong accumulation of 99mTc-HSA-D in not only the colon but also all his diapers containing his egested feces. The ratio of the diapers counts to the total counts was 17.0%, and a considerable amount of protein loss was confirmed. 99mTc-HSA-D scintigraphy has an important role in diagnosing protein-losing enteropathy, but the abdomen is the only routinely scanned area. Additional scanning of egested radiotracer and the whole body can be useful for evaluating the disease severity.

© 2018 Wolters Kluwer Health, Inc. All rights reserved. Objectives The aim of this study was to determine whether computer-assisted digital analysis and acoustic radiation force impulse (ARFI) imaging were useful for assessing pancreatic fibrosis, and if ARFI imaging predicted postoperative pancreatic fistula (POPF). Methods Seventy-eight patients scheduled to undergo pancreatic resection were enrolled. Shear wave velocity (SWV) at the pancreatic neck was measured preoperatively using ARFI imaging. Pancreatic tissue components on a whole slide image were quantified using an automatic image processing software. The relationship between SWV, fibrotic tissue content, and POPF incidence and clinical severity was analyzed. Results The median collagen fiber, fatty tissue, and acinar cell contents were 11.6%, 8.5%, and 61.3%, respectively. Unlike fatty tissue, collagen fiber content and acinar cells were correlated with SWV (ρ = 0.440, P < 0.001 and ρ =-0.428, P < 0.001, respectively). Although collagen fiber content and SWV were associated with the overall incidence of POPF (P = 0.004 and 0.001, respectively), collagen fiber content and SWV had no statistical correlation with clinically relevant POPF (P = 0.268 and 0.052, respectively). Conclusions We objectively quantified the pancreatic tissue components using an automatic image processing software. Shear wave velocity was significantly related to collagen fiber content and suggests that ARFI imaging can be useful for evaluating pancreatic fibrosis.