Published papers

Purpose: To reveal the effect of drug-eluting beads transarterial chemoembolization and Lipiodol transarterial chemoembolization on portal perfusion, and to identify factors predisposing portal vein damage after transarterial chemoembolization, based on evaluation by computed tomography during arterial portography.Material and Methods: This retrospective cohort analysis included 49 patients with hepatocellular carcinoma who underwent transarterial chemoembolization and preprocedural/follow-up computed tomography during arterial portography between October 2013 and April 2015. The preprocedural and follow-up computed tomography during arterial portography were compared to identify the following new changes suggestive of portal vein damage in the follow-up computed tomography during arterial portography: small perfusion defects, large perfusion defects, and narrowing/disappearance or portal vein obstruction. The frequency of portal vein damage after drug-eluting beads transarterial chemoembolization and Lipiodol transarterial chemoembolization was calculated, and relationships between portal vein damage and clinical variables were analyzed. Finally, a multivariate logistic regression analysis with adjustments for potentially confounding factors was performed to identify factors predisposing portal vein damage.Results: The analysis included 24 patients who underwent drug-eluting beads transarterial chemoembolization and 25 who underwent Lipiodol transarterial chemoembolization. Emergence of small perfusion defects and narrowing/disappearance or obstruction of portal vein were observed at a significantly higher frequency following drug-eluting beads transarterial chemoembolization than following Lipiodol transarterial chemoembolization (70.8% [17/24] vs. 20% [5/25]; p < 0.001; 41.7% [10/24] vs. 12% [3/25]; p = 0.019). Drug-eluting beads transarterial chemoembolization and selectivity of transarterial chemoembolization (selective [Conclusions: Portal vein damage occurred at a significantly higher frequency following drug-eluting beads transarterial chemoembolization than following Lipiodol transarterial chemoembolization, and drug-eluting beads transarterial chemoembolization was an independent predictor of portal vein damage after transarterial chemoembolization.

Background: Visualization of the inner anatomical relationship of the pulmonary veins (PVs) and left atrium (LA) is important for achieving a better success rate and avoiding complications in circumferential LA ablation for atrial fbrillation (AF). Methods and Results: Twelve patients with AF underwent computed tomography and novel post-processing images that emphasized the boundaries of the PVs and LA were produced. Conclusions: The "Transparent View" images enabled visualization of the inner anatomical relationship of the PVs and LA in the same geometry as in pulmonary venography in all cases.

Background: Before performing cardiac resynchronization therapy (CRT), it is useful to visualize the position of the coronary sinus (CS) orifice where the CS lead is inserted. Methods and Results: A raysum image was created in which the outermost 1-voxel layer of the right atrium (RA) and CS was extracted. This image enabled visualization of the positional relationship between the RA and CS ostium using the same geometry as retrograde CS venography. Conclusion: New post-processing imaging of the CS orifice will make the procedure of CRT safer.

Background: There is no post-processing technique that can display an overview image of the lumen and vessel wall of a whole heart in one image. A merging coronary lumen view (Angiographic View) with a plaque image can provide a single, comprehensive image of plaque distribution. Methods and Results: A color-coded plaque image is assigned to different computed tomography attenuation ranges in the coronary artery to visualize plaques. This plaque image is re-formatted into a maximum intensity projection image and loaded onto the Angiographic View image. Conclusions: The integrated image of the coronary lumen and vessel wall of a whole heart is feasible. This image (Plaque-loaded Angiographic View) will give effective information in explaining the distribution of coronary lesions in patients as well as providing opportunities to discuss treatment strategies.

Background: A method of displaying coronary computed tomography (CT) angiography, which enables evaluation of coronary artery disease (CAD) with fewer images and is understandable to the third person, is preferable. Methods and Results: A maximum intensity projection image was created in which contrast media in the ventricles is eliminated, enabling an overview of CAD in a single 3-dimensional (D) image that can be rotated to be viewed at various angles and is easily understood by a third person. Conclusions: A novel method of displaying coronary CT angiography in a single 3-D image has been developed and we believe it should become available for many workstations.

BACKGROUND: Detailed information is not currently available on the incidence, natural course, and management of asymptomatic abnormal prostate findings incidentally detected by radiologic evaluations after BCG therapy for non-muscle-invasive bladder cancer patients. METHODS: We identified 38 patients who were evaluated by contrast-enhanced CT scans before TUR-BT and after BCG therapy between 2006 and 2012. We evaluated the clinical courses of patients with abnormal radiologic findings of the prostate gland after BCG therapy. RESULTS: Abnormal findings on CT scans were found in the prostate glands of 11 of the 38 patients examined (28.9%), none of whom exhibited any sign or symptom associated with prostatitis. Abnormal findings included a low attenuation area (n = 6, 15.8%), contrast enhancement (n = 3, 7.9%), and a low attenuation area and contrast enhancement in the prostate gland (n = 2, 5.3%). During the follow-up, abnormal prostate findings disappeared spontaneously in most cases without any anti-bacterial or anti-tuberculous drug treatments. No significant differences were observed in patient clinical backgrounds, with the exception of post-BCG prostate volumes, between patients with and without abnormal CT findings. Furthermore, no significant differences were noted in the incidence of the adverse effects of BCG therapy, tumor recurrence rates, or progression rates between patients with and without abnormal CT findings of the prostate gland after BCG therapy. CONCLUSIONS: Asymptomatic abnormal prostate findings incidentally detected by CT after BCG therapy are not rare, and these disappear over time during the follow-up period without any treatment.

OBJECTIVE: [(99m)Tc] D,L-hexamethyl-propyeneamine oxime ((99m)Tc-HMPAO), a brain perfusion tracer, suffers significant underestimation of regional cerebral blood flow (rCBF). Lassen et al. developed their linearization algorithm to correct the influence of back-diffusion of the tracer, and proposed their parameter α as 1.5. Based on mathematical modeling and literature review, recently, a new α value of 0.5 has been proposed for Lassen's correction algorithm for (99m)Tc-HMPAO, although correction using the old α value of 1.5 was confirmed to be sufficient. Inugami et al. reported that linearization correction gives a stable correlation coefficient over a wide range of α. Our hypotheses are that statistical noise is the source of the stable correlation coefficient presented by them and that the robustness of the correlation coefficient is the reason why many studies confirmed the value of α as 1.5. METHODS: Statistical noise was added in silico to the count, whose relationship with flow was α = 0.5. Then, the count was corrected by Lassen's linearization algorithm with a variety of α. RESULTS: This study confirmed the hypothesis that smaller α values (strong correction) increase the noise at high flow values, leading to nominal increases in correlation coefficient as α decreases. CONCLUSION: Despite this, adoption of the new, smaller α value of 0.5 would be more useful clinically in regaining the contrast between low-flow and high-flow areas of the brain.

Angiomyolipoma (AML) is the most common benign solid renal neoplasm observed in clinical practice. Once thought to be a hamartoma, this neoplasm now considered among the family of PEComa. We recently provided a new radiological classification of AMLs that helps physicians understand the recent development and variety of its pathology, imaging features and its management. AMLs are divided into triphasic benign AML and epithelioid AML with malignant potential. Triphasic benign AMLs are consisted of classic AML which can be diagnosed by the detection of fat on imaging, and fat poor AML which can not. A hyperat-tenuating appearance on unenhanced CT and a T2-hypointense appearance at MRI both correspond to the smooth muscle component, are important diagnostic clues to the types of AMLs that contain few or no fat cells.

BACKGROUND: Standard imaging modality for the follow-up after prosthetic replacements for musculoskeletal tumor patients has been conventional radiography. This technique is effective in detecting subtle changes in bone adjacent to metal implants, but in many cases, radiographs do not lead to definitive diagnosis of postoperative adverse events such as acute infection, local recurrence of soft tissue tumor or soft tissue local recurrence of osseous sarcoma. Conventional MRI sequences have not been effective due to metal artifacts. In this study, we tried to elucidate the effectiveness of metal artifact suppression using novel sequence, multiacquisition variable-resonance image combination (MAVRIC), after musculoskeletal tumor surgeries. METHODS: We retrospectively analyzed 5 cases of malignant bone and soft tissue sarcoma patients who were reconstructed with metal prosthesis after wide resection of tumors. Images obtained using MAVRIC and short tau inversion recovery (STIR) were compared side by side. The paired MAVRIC and STIR images were qualitatively compared independently by two specialists for 4 parameters: visualization of bone - implant interface, visualization of surrounding soft tissues, image blurring, and overall image quality. Quantitatively, paired images were reviewed to identify the slice where the metal artifact was maximal, and a region of interest encompassing the implant and surrounding artifact was drawn using Advantage Workstation (GE Healthcare, Japan). RESULTS: There were no local recurrences that were detected. By utilizing MAVRIC, visualization of the bone - implant interface and visualization of the surrounding soft tissue were significantly improved in MAVRIC compared to STIR. Although blurring was worse on the MAVRIC acquisitions, the overall image quality was still better on MAVRIC. Quantitatively, the area of metal artifact measured using MAVRIC was markedly less compared to STIR (61.4 cm(2) vs 135.9 cm(2)). CONCLUSION: Despite the relatively small number of cases in the present study, our observation strongly suggests that MAVRIC is able to improve the quality of images by decreasing the artifact caused by endoprosthesis, frequently utilized in reconstruction of musculoskeletal tumor patients. Further installments of conventional imaging sequences with the addition of gadolinium - enhancement will enable increased accuracy in diagnosing local recurrences of sarcoma patients.

Background: Recently, a non-invasive method using computational fluid dynamics to calculate vessel-specific fractional flow reserve (FFRct) from routinely acquired coronary computed tomography angiography (CTA) was described. The Analysis of Coronary Blood Flow Using CT Angiography: Next Steps (NXT) trial, which was a prospective, multicenter trial including 254 patients with suspected coronary artery disease, noted high diagnostic performance of FFRct compared with invasive FFR. The aim of this post-hoc analysis was to assess the diagnostic performance of non-invasive FFRct vs. standard stenosis quantification on coronary CTA in the Japanese subset of the NXT trial.Conclusions: FFRct has high diagnostic performance compared with invasive FFR in the Japanese subset of patients in the NXT trial.Methods and Results: A total of 57 Japanese participants were included from Okayama University (n=36), Kyoto University (n=17), and Keio University (n=4) Hospitals. Per-patient diagnostic accuracy of FFRct (74%; 95% confidence interval [CI]: 60–85%) was higher than for coronary CTA (47%; 95% CI: 34–61%, P<0.001) arising from improved specificity (63% vs. 27%, P<0.001). FFRct correctly reclassified 53% of patients and 63% of vessels with coronary CTA false positives as true negatives. When patients with Agatston score >1,000 were excluded, per-pa-tient accuracy of FFRct was 83% with a high specificity of 76%, similar to the overall NXT trial findings.

© 2019, Springer Japan KK, part of Springer Nature. Myocardial T1 mapping is clinically valuable for assessing the myocardium, and modified look-locker inversion-recovery (MOLLI) approaches have been commonly used for measuring myocardial T1 values. To date, several other sequences have been developed for measuring myocardial T1 values, and saturation-recovery-based sequences have been shown to be less dependent on various factors, such as T2 times and magnetization transfer, than inversion-recovery techniques. Systematic differences in T1 values between different sequences have been reported; therefore, definition of the normal range of native T1 values is required before clinical usage can begin. The purpose of this study was to evaluate the reference range and sex dependency of native T1 values in the myocardium measured using one such saturation-recovery sequence, i.e., saturation method using adaptive recovery times for cardiac T1 mapping (SMART1Map). Myocardial T1 values were compared between SMART1Map and MOLLI in 24 young healthy volunteers at 1.5 T and 3 T, and differences in the T1 values between the sexes were assessed. The mean native T1 values in the myocardium were significantly longer with SMART1Map than MOLLI [1530.4 ± 49.2 vs 1222.1 ± 48.9 ms at 3 T (p < 0.001) and 1227.3 ± 41.9 ms vs 1014.8 ± 49.4 ms at 1.5 T (p < 0.001)]. A significant difference between the sexes was observed in the T1 values obtained using each sequence, excluding SMART1Map at 3 T. The SMART1Map has a potential advantage to overcome the shortcoming of MOLLI, which underestimates T1 values; however, the sex-dependent difference remains obscure using SMART1Map.

© 2020, The International Urogynecological Association. Introduction and hypothesis: This study was aimed at comparing pelvic floor parameters between the standing and supine positions using upright computed tomography (CT) and evaluating the effects of sex and age in normal healthy volunteers. Methods: In total, 139 volunteers (70 men, mean 46.7 years; 69 women, mean 47.3 years) underwent both upright CT in the standing position and conventional CT in the supine position. The distances from the bladder neck to the pubococcygeal line (PCL) and anorectal junction (ARJ), defined as the posterior aspect of the puborectalis muscle, to PCL were measured. The length, width, and area of the levator hiatus (LH) were measured on oblique axial images. Results: The bladder neck (men, 22.2 ± 4.9 mm vs 28.3 ± 5.3 mm; women, 9.0 ± 5.1 mm vs 19.0 ± 4.0 mm) and ARJ (men, −18.8 ± 5.5 mm vs −12.1 ± 5.1 mm; women, −20.0 ± 4.7 mm vs −11.2 ± 4.3 mm) were significantly lower in the standing position than in the supine position (all p < 0.0001). The LH area (men, 1,990 ± 380 mm2 vs 1,697 ± 329 mm2; women, 2,284 ± 344 mm2 vs 1,811 ± 261 mm2) was significantly larger in the standing position (both p < 0.0001). Differences in all parameters between the standing and supine positions were larger in women than in men. ARJ in women showed a significant tendency to descend with age only in the standing position (r = −0.29, p = 0.017). Conclusions: The bladder neck and ARJ descend and the LH area enlarges in the standing position. Pelvic floor mobility is greater in women than in men. Descent of the ARJ in the standing position is associated with aging in women.

Objectives: To investigate neuroendocrine carcinoma (NEC) of the uterine cervix cases for MRI features and staging, as well as pathological correlations and survival. Results: FIGO was I in 42, II in 14, III in 1, and IV in 5 patients. T2-weighted MRI showed homogeneous slightly high signal intensity and obvious restricted diffusion (ADC map, low intensity; DWI, high intensity) throughout the tumor in most cases, and mild enhancement in two-thirds. In 50 patients who underwent a radical hysterectomy and lymphadenectomy without neoadjuvant chemotherapy (NAC), intrapelvic T staging by MRI overall accuracy was 88.0% with reference to pathology staging, while patient-based sensitivity, specificity, and accuracy for metastatic pelvic lymph node detection was 38.5%, 100%, and 83.3%, respectively. During a mean follow-up period of 45.6 months (range 4.3-151.0 months), 28 patients (45.2%) experienced recurrence and 24 (38.7%) died. Three-year progression-free and overall survival rates for FIGO I, II, III, and IV were 64.3% and 80.9%, 50% and 64.3%, 0% and 0%, and 0% and 0%, respectively. Materials and Methods: Sixty-two patients with histologically surgery-proven uterine cervical NEC were enrolled. Twelve received NAC. Clinical data, pathological findings, and pretreatment pelvic MRI findings were retrospectively reviewed. Thirtytwo tumors were pure NEC and 30 mixed with other histotypes. The NECs were small cell type (41), large cell type (18), or a mixture of both (3). Conclusions: Homogeneous lesion texture with obvious restricted diffusion throughout the tumor are features suggestive of cervical NEC. Our findings show that MRI is reliable for T staging of cervical NEC. Copyright:

Limited data exist with regard to the outcome of the Nuss procedure for pectus excavatum repair in adults. Here, we analysed changes in lung capacity and thoracic morphology based on computed tomography (CT) imaging in adults with pectus excavatum before surgery, during bar insertion and after bar removal. Patients who underwent the Nuss procedure for pectus excavatum after the age of 20 were included in this study. Chest CT scans of the included participants were taken before the Nuss procedure, immediately before removal of the pectus bar and 6 months after removal of the pectus bar. Lung capacity and thoracic morphology measurements were made from the CT scans. Six patients aged 24–43 years were included in this study. After the Nuss procedure, lung capacity was decreased in all patients. Although the pectus bar was removed, lung capacity had not significantly increased and was almost the same volume as before the Nuss procedure. After the Nuss procedure, the funnel chest shape had improved in all cases, patients’ thoracic spine had also moved forward as the thorax moved forward and patients’ stoop had improved. Despite a lack of change in lung capacity, surgical modification should be considered to reduce stress on the thoracic spine and in turn, reduce pain in patients with pectus excavatum. However, further long-term observation seems necessary.

CT angiography (CTA) based on the data acquired by multidetector-row CT (MDCT) is an established, minimally invasive modality for imaging peripheral arteries. CTA has been used to assess peripheral arterial disease before treatment, and it has replaced conventional angiography for the diagnostic evaluation of peripheral arteries. MDCT can optimize both the long scan length and spatial resolution. CTA using MDCT depicts the fine structures of vessels. Recently, automated CTA analysis software has been developed for measurement of the vascular lumen. The software can automatically measure the diameters of short axial sections at the post-processing workstation. Measurement of the vascular lumen is useful in the planning of intravascular treatment for peripheral arterial disease. CTA is also utilized in assessing the intravascular lumen after metallic stent placement.