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Abstract This study aimed to compare tumor lesion detectability and diagnostic accuracy of whole-body magnetic resonance imaging (WB-MRI) and radioiodine-labeled meta-iodo-benzylguanidine (mIBG) imaging techniques in patients with metastatic pheochromocytoma and paraganglioma (PPGL). This retrospective study included 13 patients had pheochromocytoma and 5 had paraganglioma, who were all suspected of having metastatic tumors. Each patient underwent WB-MRI and 123I-mIBG as a pretreatment screening for 131I-mIBG therapy. Two expert reviewers evaluated WB-MRI, 123I-mIBG images, and post-therapy 131I-mIBG images for the presence of metastatic lesions in the lungs, bones, liver, lymph nodes, and other organs. Diagnostic measures for detecting metastatic lesions, including sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristics (ROC)—area under the curve (AUC), were calculated for each imaging technique. We analyzed WB-MRI images for detecting metastatic lesions, which demonstrated sensitivity, specificity, accuracy, PPV, NPV, and AUC of 82%, 97%, 90%, 96%, 86%, and 0.92, respectively. These values were 83%, 95%, 89%, 94%, 86%, and 0.90 in 123I-mIBG images and 85%, 92%, 89%, 91%, 87%, and 0.91 in post-therapy 131I-mIBG images, respectively. Our results reveal the comparable diagnostic accuracy of WB-MRI to one of the mIBG images.

A 53-year-old female with primary biliary cholangitis was referred for the evaluation of a hepatic nodule identified during routine imaging. Ultrasonography revealed a homogeneous, hypoechoic, 18 mm nodule in segment 3 of the liver. On dynamic CT and MRI, the nodule showed mild enhancement at the hepatic artery-dominant phase. On diffusion-weighted images, the nodule exhibited pronounced hyperintensity with accompanying wedge-shaped perinodular hyperintensity (comet and comet-tail appearance). The nodule showed a portal perfusion defect on CT during arterial portography, and mild enhancement on CT during hepatic arteriography (CTHA). A nodular and wedge-shaped perinodular enhancement (comet and comet-tail appearance) in the CTHA was also clearly observed. The nodule demonstrated abnormal FDG uptake on 18F-FDG-PET/CT. An excisional biopsy was performed for histopathological diagnosis, and the nodule was diagnosed as reactive lymphoid hyperplasia (RLH). Diagnosing hepatic RLH by imaging is challenging due to its imaging findings overlapping with those of various malignant tumors, especially the nodular type of lymphomas, making differentiation particularly difficult. However, radiologists should note the perinodular early enhancement and the perinodular hyperintensity on diffusion weighted images, which are thought to be key imaging findings of RLH, along with other characteristics such as a single, small, homogeneous nodule with mild early enhancement and marked restricted diffusion. We propose to name the nodular lesion with perinodular early enhancement/hyperintensity on diffusion weighted images as 'comet and comet-tail appearances'.

Purpose: To assess the feasibility of the 6-point Dixon method for evaluating liver masses. We also report our initial experience with the quantitative values in various liver masses on a 3T system. Materials and methods: Of 251 consecutive patients for whom 6-point Dixon was employed in abdominal magnetic resonance imaging scans between October 2020 and October 2021, 117 nodules in 117 patients with a mass diameter of more than 1 cm were included in the study. Images for measuring the proton density fat fraction (PDFF) and R2 * values were obtained using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation-quantitative technique for liver imaging. Two radiologists independently measured PDFF (%) and R2 * (Hz). Inter-reader agreement and the differences between readers were examined using intra-class correlation coefficient (ICC) and the Bland-Altman method, respectively. PDFF and R2 * values in differentiating liver masses were examined. Results: The masses included hepatocellular carcinoma (n = 59), cyst (n = 20), metastasis (n = 14), hemangioma (n = 8), and others (n = 16). The ICCs for the region of interest (mm2), PDFF, and R2 * were 0.988 (95 % confidence interval (CI): 0.983, 0.992), 0.964 (95 % CI: 0.949, 0.975), and 0.962 (95 % CI: 0.941, 0.975), respectively. The differences of measurements between the readers showed that 5.1 % (6/117) and 6.0% (7/117) for PDFF and R2 * , respectively, were outside the 95 % CI. Conclusion: Our observation indicates that the 6-point Dixon method is applicable to liver masses.

Abstract Retzius-sparing robot-assisted radical prostatectomy (RARP) has been reported to exhibit better postoperative urinary continence, but the reasons behind this are unknown. This study included 254 cases who underwent RARP and underwent postoperative dynamic MRI. We measured the urine loss ratio (ULR) immediately after postoperative urethral catheter removal and investigated its affecting factors and the mechanisms. Nerve-sparing (NS) techniques was performed in 175 (69%) unilateral and 34 (13%) bilateral cases, whereas Retzius-sparing in 58 (23%) cases. The median ULR early after indwelling catheter removal in all patients was 4.0%. The multivariate analysis was performed on factors that reduce ULR and found that the following factors were associated with ULR: younger age, NS and Retzius-sparing, which were significant. Additionally, dynamic MRI findings showed that membranous urethral length and the anterior rectal wall movement toward the pubic bone during abdominal pressure were significant factors. The movement observed on the dynamic MRI during abdominal pressure was thought to reflect an effective urethral sphincter closure mechanism. Long membranous urethral length and an effective urethral sphincter closure mechanism during abdominal pressure were considered effective for favorable urinary continence after RARP. NS and Retzius-sparing were clearly shown to have an additive effect in preventing urinary incontinence.

Abstract Aims Right‐sided filling pressure is elevated in some patients with heart failure (HF) and preserved ejection fraction (HFpEF). We hypothesized that right atrial pressure (RAP) would represent the cumulative burden of abnormalities in the left heart, pulmonary vasculature, and the right heart. Methods and results Echocardiography was performed in 399 patients with HFpEF. RAP was estimated from inferior vena cava morphology and its respiratory change [estimated right atrial pressure (eRAP)], and patients were divided according to eRAP (3 or ≥8 mmHg). Patients with higher eRAP displayed more severe abnormalities in LV diastolic function as well as right heart structure and function than those with normal eRAP. Cardiac deaths or HF hospitalization occurred in 84 patients over a median follow‐up of 19.0 months (interquartile range 6.7–36.9). The presence of higher eRAP was independently associated with an increased risk of the composite outcome (adjusted hazard ratio 2.20 vs. normal eRAP group, 95% confidence interval 1.34–3.62, P = 0.002). Kaplan–Meier curves separating the patients into four groups based on eRAP and E/e' ratio showed that event‐free survival varied among the groups, providing an incremental prognostic value of eRAP over E/e' ratio. The classification and regression tree analysis demonstrated that eRAP was the strongest predictor of the outcome followed by right ventricular dimension, E/e' ratio, and estimated right ventricular systolic pressure, stratifying the patients into four risk groups (incident rate 8.8–72.2%). Conclusions These data may provide new insights into the prognostic role of RAP in the complex pathophysiology of HFpEF and suggest the utility of eRAP for the risk stratification in patients with HFpEF.

Purpose: To evaluate the feasibility of renal artery-based segmentation of kidneys with renal cell carcinoma (RCC), based on three-dimensional (3D) software for the simulation of segmental artery clamping (SAC), and to correlate it with RENAL nephrometry score. Methods: Fifty RCCs (< 4 cm) identified from a pathological database search between January 2015 and January 2018 were included retrospectively. On computed tomography (CT) images, the relevant kidney, tumor, and renal artery were annotated semi-automatically on the commercial workstation, and renal artery-based segmentation was performed using 3D Voronoi diagrams. Simulation of SAC was performed by a radiologist and urologist in consensus. The volume of the whole kidney and tumor and estimated rescued volume for possible SAC cases were calculated. The correlation between possible SAC and RENAL nephrometry score was investigated. The reproducibility of the calculation of each volume and the interrater reliability of SAC simulation were assessed. Results: In the anatomical analysis, 44 patients had a single main renal artery and six had two main renal arteries, and of these, an early division pattern was observed in 11 cases. In the 3D simulation software, 22 out of 50 cases (44 %) were determined as possible SAC. The agreement of the SAC simulation was excellent (kappa = 0.96). RENAL nephrometry score was significantly different in the anterior/posterior and exophytic/endophytic components between possible and impossible SAC groups. Conclusions: Renal artery-based segmentation of kidneys with RCC on CT images using 3D simulation software is feasible for effectively estimating the possibility of SAC with high reproducibility.

Abstract Retzius-sparing robot-assisted radical prostatectomy (RS-RARP) exhibits better postoperative urinary continence than conventional RARP (C-RARP) via the anterior approach. However, the reasons behind this are unknown. Herein, early postoperative urinary incontinence and anatomical differences of 51 propensity score-matched C-RARP and RS-RARP cases were compared. Dynamic magnetic resonance imaging (MRI) was performed before and after surgery to examine the pelvic anatomical changes under abdominal pressure. The median urine loss ratios in the early postoperative period after C-RARP and RS-RARP were 11.0% and 1.0%, respectively. Postoperative MRI revealed that the anterior bladder wall was fixed in a higher position after RS-RARP compared with its position after C-RARP. Dynamic MRI after C-RARP showed that cephalocaudal compression of the bladder while applying abdominal pressure caused the membranous urethra to expand and the urine to flow out. After RS-RARP, the rectum moved forward during abdominal pressure, and the membranous urethra was compressed by closure from behind. This is the first study using dynamic MRI to reveal the importance of high attachment of the anterior bladder wall for the urethral closure mechanism during abdominal pressure. RS-RARP, which can completely preserve this mechanism, is less likely to cause stress urinary incontinence compared with C-RARP.

PurposeTo compare the inter-observer variability of apparent diffusion coefficient (ADC) values of prostate lesions measured by 2D-region of interest (ROI) with and without specific measurement instruction.MethodsForty lesions in 40 patients who underwent prostate MR followed by targeted prostate biopsy were evaluated. A multi-reader study (10 readers) was performed to assess the agreement of ADC values between 2D-ROI without specific instruction and 2D-ROI with specific instruction to place a 9-pixel size 2D-ROI covering the lowest ADC area. The computer script generated multiple overlapping 9-pixel 2D-ROIs within a 3D-ROI encompassing the entire lesion placed by a single reader. The lowest mean ADC values from each 2D-small-ROI were used as reference values. Inter-observer agreement was assessed using the Bland-Altman plot. Intraclass correlation coefficient (ICC) was assessed between ADC values measured by 10 readers and the computer-calculated reference values.ResultsTen lesions were benign, 6 were Gleason score 6 prostate carcinoma (PCa), and 24 were clinically significant PCa. The mean±SD ADC reference value by 9-pixel-ROI was 733 ± 186 (10-6 mm2/s). The 95% limits of agreement of ADC values among readers were better with specific instruction (±112) than those without (±205). ICC between reader-measured ADC values and computer-calculated reference values ranged from 0.736-0.949 with specific instruction and 0.349-0.919 without specific instruction.ConclusionInterobserver agreement of ADC values can be improved by indicating a measurement method (use of a specific ROI size covering the lowest ADC area).

A method to design the function of the brassiere cup shape as developable surfaces and its developed shape using Gaussian Process Regression is proposed. A developable surface, which is generated by sweeping a straight line along a three-dimensional curve, can be seen many products such as ships, buildings, clothes, and so on. The shape has not only its aim which can be formulated but also that which cannot be formulated such aesthetics. In this paper, we focus on a brassiere cup. A brassiere cup is composed of several patterns and the cup shape is designed by repeatedly making paper cup model and then checking its three-dimensional shape. For improvement of design efficiency of brassieres, such trial and error must be reduced. The difficulty of the design process is caused by the function of a brassiere cup. Its function, such as to enhance woman’s breast size, et.al., is difficult to formulate and unclearly correlated with its three-dimensional cup shape. In this paper, we propose a method to support the design of the three-dimensional shape of a cup and its developed shape by machine learning when the cup shape and quantitatively evaluated value of its function are given as a set of data. First, we formulate the cup shape as developable surface using differential geometry. Then, we propose the method to extract the attribute from the three-dimensional cup shape based on the differential geometry and a predictor of an output value for its attribute using Gaussian Process Regression. The validity of the method is confirmed by a numerical experiment regarding the evaluated value using its volume and size. Finally, we propose a method to design the cup shape using this predictor. We experimented whether our proposed method can output the approximate cup shape when the evaluated value of the cup is given.

Background: Inchworm sign is considered to be a characteristic finding in non-muscle invasive bladder cancer (NMIBC). Nevertheless, pathologically diagnosed muscle invasive bladder cancers (MIBCs) are occasionally diagnosed from tissue obtained by transurethral resection of bladder tumor (TURBT) in patients with inchworm sign. Methods: We retrospectively investigated the factors related to muscle invasive status in bladder cancer associated with inchworm sign and the role of inchworm sign in tumor outcomes following TURBT. Results: Of the 109 patients with inchworm sign, 94 (86.2%) and 15 (13.8%) were NMIBC and MIBC, respectively. Non-papillary tumors (hazard ratio (HR): 9.55, 95% confidence interval (CI): 2.07–44.10; p < 0.01) and tumors located in the bladder neck (HR: 7.73, 95% CI: 1.83–32.76; p < 0.01) were significant predictors of MIBC in bladder cancer with inchworm sign. Furthermore, recurrence-free survival (RFS) and progression-free survival were compared between patients with NMIBC with and without inchworm sign; however, no significant differences were found. In patients with NMIBC with inchworm sign, positive urine cytology was a prognostic factor for RFS (HR: 1.90, 95% CI: 1.04–3.48; p = 0.04). Conclusions: In bladder cancer with inchworm sign, 86.2% were NMIBC. Even in the case of inchworm sign, the presence of a non-papillary tumor or a bladder neck tumor before TURBT should be noted because of the possibility of MIBC. In this study, the inchworm sign was not a prognostic factor in patients with NMIBC.

Advances in imaging technologies have increased the opportunities for treating small-diameter renal cell carcinomas (RCCs) in the elderly. This retrospective study based on real-world clinical practice compared perioperative complications, preoperative and postoperative renal function, recurrence-free survival, and overall survival in elderly patients with RCC who had undergone robot-assisted partial nephrectomy (RAPN) or percutaneous cryoablation (PCA). A total of 99 patients (aged ≥70 years), including 50 and 49 patients in the RAPN and PCA groups, respectively, were analyzed. In the entire cohort, Clavien–Dindo grade ≥3 complications occurred in only one patient who had undergone RAPN. Renal function was significantly lower in the postoperative period than in the preoperative period in both the RAPN and PCA groups. The recurrence-free survival and overall survival rates were worse in the PCA group than in the RAPN group, albeit not significantly. RAPN was considered a safe and effective method for treating RCCs in elderly patients. Moreover, although the recurrence rate was slightly higher in the PCA group than in the RAPN group, PCA was deemed to be a safe alternative, especially for treating patients in whom general anesthesia poses a high risk.

Background: Treatment strategies have changed dramatically in recent years with the development of a variety of agents for metastatic hormone-naïve prostate cancer (mHNPC). There is a need to identify prognostic factors for the appropriate choice of treatment for patients with mHNPC, and we retrospectively examined these factors. Methods: Patients with mHNPC treated at our institution from 2000 to 2019 were included in this study. Overall survival (OS) was estimated retrospectively using the Kaplan–Meier method, and factors associated with OS were identified using univariate and multivariate analyses. A prognostic model was then developed based on the factors identified. Follow-up was terminated on 24 October 2021. Results: The median follow-up duration was 44.2 months, whereas the median OS was 85.2 months, with 88 patients succumbing to their disease. Multivariate analysis identified Gleason pattern (GP) 5 content, bone scan index (BSI) ≥ 1.5, and lactate dehydrogenase (LDH) levels ≥ 300 IU/L as prognostic factors associated with OS. We also developed a prognostic model that classified patients with mHNPC as low risk with no factor, intermediate risk with one factor, and high risk with two or three factors. Conclusions: Three prognostic factors for OS were identified in patients with mHNPC, namely GP5 inclusion, BSI ≥ 1.5, and LDH ≥ 300. Using these three factors, we developed a new prognostic model for OS that can more objectively predict patient prognosis.

Many products such as ships, buildings, and clothes contain developable surfaces generated by sweeping a straight line along a three-dimensional curve. An automated design process does not exist due to difficulties satisfying the conditions of a developable surface. This study proposes a method to design a developable surface from the intended data points using the design process of a two-piece brassiere cup as an example. Here, we model a developable surface based on the differential geometry, which converts the design to its boundary curves. Then we formulate the error between the developable surface and the data points from the geometry condition and the optimization problem in the design process. Our method is verified by applying it to three examples: a shape composed of two developable surfaces, a sphere, which is a non-developable surface, and a realistic breast shape.

Objective: To describe first episodes of bacterial cholangitis complicating autosomal dominant polycystic kidney disease (ADPKD) and autosomal dominant polycystic liver disease (ADPLD) and to identify risk factors for cholangitis episodes among patients with ADPKD-associated polycystic liver disease (PLD). Patients and Methods: We searched the electronic medical records at our tertiary referral center for episodes of cholangitis in patients with ADPKD or ADPLD from January 1, 1996, through June 30, 2017. Cases were categorized as suspected or definite cholangitis by expert review. Clinical, laboratory, and radiologic data were manually abstracted. A nested case-control study was conducted to investigate risk factors for cholangitis in patients with ADPKD. Results: We identified 29 cases of definite or suspected cholangitis complicating PLD (24 with ADPKD-associated PLD and 5 with ADPLD). Among patients with definite cholangitis in ADPKD-associated PLD (n=19) vs ADPLD (n=4), the mean ± SD age was 62.4±12.2 vs 55.1±8.6 years, and 9 (47.4%) vs 0 (0%), respectively, were male. The odds of gallstones (odds ratio [OR], 21.6; 95% CI, 3.17-927; P

Mucinous tumors are a common ovarian cystic tumor, having a characteristic finding on MR imaging, the so-called stained glass appearance. We report a rare case of a solidified mucinous tumor of the ovary, which showed unique findings on MR images. The tumor demonstrated hypointensity on T2-weighted images, not stained glass appearance, mimicking ovarian fibrous tumor such as thecoma-fibroma. Histopathological examination confirmed solidified contents of the tumor with numerous septa and diagnosed mucinous borderline tumor/atypical proliferative tumor. Keywords: Mucinous tumor, Ovary, Stained glass appearance, MRI

A method to design a developable surface and its developed shape is proposed. A developable surface, which is generated by sweeping a straight line along a three-dimensional curve, can be seen many products such as ships, buildings, clothes, and so on. Although it is important to design the surface in case that designers give some constraints, its design process is not automated because of the difficulty of its modeling. Especially, cloth products are required to design not only their three-dimensional shapes but also their developed shapes. Therefore, we aim to propose a method to design the surface satisfying some constraints and its developed shape. As an example, we assume that some constraints are related to the control points of a curve in a developable surface. In this paper, it is revealed that the direction of a generatrix can be determined geometrically when a pair of three-dimensional curves are given. Moreover, in order to obtain a steadier shape, not only this condition but also the potential energy of the surface should be considered. From the above, we formulate optimization problems, upon this design process, which have different objective functions: one is the condition of a developable surface and the other is its bending energy. We compared and examined bending energies and maximum principal curvatures obtained by two different optimization problems. In order to verify our proposed method, we performed an experiment and confirmed its validity.

Cystic neoplasms arising from the prostate are rare, and stromal tumours of uncertain malignant potential and the spectrum of cystic epithelial tumours of the prostate are the major differential diagnoses of a cystic prostatic neoplasm. We report a case of a stromal tumour of uncertain malignant potential, which showed a multilocular cystic mass with some solid components. The solid component of the tumour did not show substantial diffusion restriction and uptake of 18F-FDG-PET, and this could be the critical finding suggesting a stromal tumour of uncertain malignant potential rather than a malignant cystic epithelial tumour.

PURPOSE:To evaluate the utility of photoacoustic imaging in measuring changes in renal oxygen saturation after ischemia-induced acute kidney injury, and to compare these measurements with histological findings and serum levels of kidney function. MATERIAL AND METHODS:Acute kidney injury was induced by clamping the left renal pedicle in C57Bl/6 mice, with a 35-min ischemic period used to induce mild renal injury (14 mice) and a 50-min period for severe injury (13 mice). The oxygen saturation was measured before induction, and at 5 time-points over the first 48 h after induction, starting at 4 h after induction. Oxygen saturation, histological score, kidney volume, and the 24 h creatinine clearance rate and serum blood urea nitrogen were also measured on day 28. Between-group differences were evaluated using a Mann-Whitney U-test and Dunn's multiple comparisons. The association between oxygen saturation and measured variables was evaluated using Spearman's correlation. A receiver operator characteristic curve was constructed from oxygen saturation values at 24 h after heminephrectomy to predict chronic renal function. RESULTS:The oxygen saturation was higher in the mild than severe renal injury group at 24 h after induction (73.7% and 66.9%, respectively, P

Purpose: This multi-scanner study aimed to investigate the validity of single breath-hold (BH) diffusionweighted imaging (DWI) using simultaneous-multislice (SMS) echo-planar imaging in multiple abdominal organs to enable faster acquisition and reliable quantification of apparent diffusion coefficient (ADC). Methods: SNR, geometric distortion (GD), and ADC in a phantom; the ADC in the liver, renal cortex, paraspinal muscle, spleen, and pancreas; and the signal intensity ratio of the portal vein-to-muscle (SIRpv_m) in healthy volunteers were compared between BH- and respiratory-triggered (RT) DWI with b-values of 0 and 800 s/mm² in two different MRI scanners. Results: The phantom study showed that the SNR of BH-DWI was significantly lower than that of the RTDWI (P < 0.05 for both scanners), whereas the GD and ADC of BH-DWI did not differ significantly from those of the RT-DWI (P = 0.09-0.60). In the volunteer study, the scan times were 23 seconds for BH-DWI and 184 ± 33 seconds for RT-DWI, respectively. The ADC of the liver in BH-DWI was significantly lower than that in RT-DWI (P < 0.05 for both scanners), whereas there were no significant differences in the ADCs of the renal cortex, paraspinal muscle, spleen, or pancreas between BH-DWI and RT-DWI (P = 0.07-0.86). The SIRPV-M in BH-DWI was significantly smaller than in RT-DWI (P < 0.05 for both scanners). Conclusion: The proposed method enables the acquisition of abdominal diffusion-weighted images in a single BH. [ABSTRACT FROM AUTHOR]