菊地 智博

Abstract Background Large-scale CT-based reference standards for abdominal organ volume, incorporating age, sex, and body size, are limited. Purpose To establish sex- and age-specific reference distributions for major abdominal organ volumes on non-contrast abdominopelvic CT in a nationwide Japanese cohort to provide a foundation for automated clinical assessment and dose optimization. Materials and Methods In this retrospective, multicenter study, using the Japan Medical Image Database, we identified all non-contrast abdominopelvic CT examinations performed in 2024. Unique adults with available data on age, sex, height, and weight were included in this study. The final sample comprised 49,764 examinations (26,456 men and 23,308 women) conducted at nine institutions. Automated segmentation (TotalSegmentator v2.10.0) was used to produce organ volumes, excluding hollow viscera. The sex-specific 10th, 25th, 50th, 75th, and 90th percentiles were calculated. Age–volume relationships of body surface area (BSA)-normalized volumes (mL/m ² ) were modeled using natural cubic splines (four degrees of freedom) separately by sex. Results Median (mL) male vs female volumes were as follows: liver, 1194.7 vs 1024.0; pancreas, 63.6 vs 52.2; spleen, 118.1 vs 95.1; kidneys (total), 268.3 vs 221.2; adrenals (total), 6.6 vs 4.2; iliopsoas (total), 483.4 vs 317.7; prostate, 24.9 (men only). Age–volume relationships of BSA-normalized volumes showed convex patterns for the liver, pancreas, and kidneys in both sexes and for male adrenal glands; lower values in older age groups for the spleen and iliopsoas in both sexes; and higher values in older age groups for the prostate and female adrenal glands. Conclusion This nationwide Japanese CT cohort provides sex- and age-resolved volumetric reference standards. These standards enable objective identification of abnormalities, support personalized medicine, and facilitate automated AI-based reporting to reduce radiologist workload and optimize radiation dose protocols. Key Results Median volumes (men vs women, mL): liver 1195/1024; pancreas 64/52; spleen 118/95; kidneys 268/221; adrenals 6.6/4.2; iliopsoas 483/318; prostate 25. Body surface area–normalized age–volume relationships were convex for liver, pancreas, and kidneys in both sexes and for male adrenal glands. Spleen and iliopsoas declined monotonically with age in both sexes, whereas prostate and female adrenal glands increased monotonically.

PURPOSE: To examine magnetic resonance imaging (MRI) features of mesonephric-like adenocarcinoma (MLA) of the uterine corpus. METHOD: MRI features of 19 patients with pathologically proven MLA of the uterine corpus were retrospectively compared with those of 95 patients with endometrial endometrioid carcinoma (EEC). RESULTS: Most patients with MLA were postmenopausal. Advanced FIGO stages were more common in the MLA than in the EEC group (63.2 % vs. 18.9 %, p < 0.001). On MRI, endophytic growth into the myometrium were more frequent in the MLA than in the EEC group (68.4 % vs. 14.7 %, p = 0.005). The median maximum tumor diameter in the MLA group (52.4 mm) tended to be larger than that in the EEC group (38.9 mm), although the difference was not statistically significant (p = 0.374). The tumor-to-muscle signal intensity ratio (SIR) on fat-suppressed gadolinium-enhanced T1-weighted gradient-echo imaging was higher in the MLA group than in the EEC group. (1.67 vs. 1.36, p = 0.002). The SIR on diffusion-weighted imaging (DWI) was comparable between the two groups (8.35 vs. 6.72, p = 0.330). The apparent diffusion coefficient value was lower in the MLA than in the EEC group (0.69 10-3 mm2/s vs. 0.76 × 10-3 mm2/s, p = 0.003). Coexisting adenomyosis was more frequent in the MLA than in the EEC group (52.6 % vs. 21.1 %, p = 0.034). The concordance rate between MRI and pathology for adenomyosis coexistence was 84.2 % for MLA, 87.4 % for EEC, and 86.8 % overall. MLA of the uterine corpus was identified in two patients, characterized by development independent of and discontinuous from the endometrium, whereas EEC in all patients demonstrated continuity with the endometrium. CONCLUSIONS: MRI of MLA of the uterine corpus typically demonstrates large, diffuse, and endophytic growth into the myometrium, with strong contrast enhancement and more restricted diffusion compared to EEC, with coexisting adenomyosis present in over 50% of patients. Therefore, postmenopausal women with adenomyosis should be carefully evaluated for MLA on MRI, particularly using DWI.

PURPOSE: Complete androgen insensitivity syndrome (CAIS) and Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) share common clinical features such as female phenotype, vaginal hypoplasia, and primary amenorrhea. Magnetic resonance imaging (MRI) is performed to investigate the cause of primary amenorrhea. However, the MRI features are also similar in both disorders. They are ultimately diagnosed by chromosome testing, but there is a possibility of misdiagnosis if chromosome testing is not performed. This study aimed to identify MRI features that are useful for differentiating CAIS from MRKHS. METHOD: This multicenter retrospective study included 12 patients with CAIS and 19 patients with MRKHS. Three radiologists blindly evaluated the following features: (1) detection of vagina, (2) detection of nodular and cystic structures in the lateral pelvis; undescended testicles and paratesticular cysts in CAIS and rudimentary uteri and ovaries in MRKHS, (3) their location, (4) number of cysts in the cystic structures, and (5) signal intensity on diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) values of the nodular structures. Statistical comparisons were performed using Mann-Whitney U and Fisher's exact tests. RESULTS: Compared with MRKHS, the CAIS group showed significantly detectable vagina, more ventrally located nodular and cystic structures, fewer cysts within the cystic structures, and nodular structures with higher signal intensity on DWI and lower ADC values. CONCLUSIONS: MRI features of detectable vagina, location of nodular and cystic structures, number of cysts within the cystic structures, signal intensity on DWI and ADC values of the nodular structures were useful in differentiating CAIS from MRKHS.

<jats:title>Abstract</jats:title><jats:sec><jats:title>Introduction</jats:title><jats:p>This study aimed to identify cases that require a three‐dimensional‐printed kidney model in robot‐assisted partial nephrectomy.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We enrolled 93 patients undergoing robot‐assisted partial nephrectomy for renal tumors at a single institution between November 2018 and May 2021. The endpoints were how often and how long the surgeon consulted the three‐dimensional‐printed model, determined using intraoperative video. Multivariate analyses of the endpoints were adjusted by preoperative patient and kidney characteristics, including renal vascular complexity that was defined as the number of vascular branches penetrating the surface tangential to the ventral side of the kidney.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Of the 93 cases, the median frequency and duration of intraoperative three‐dimensional‐printed model consultation were four times and 39 s, respectively. The multivariate linear regression analyses showed that the frequency of intraoperative three‐dimensional‐printed model consultation by the surgeon was significantly related to the complexity of the arterial structure (≥4 branches), presence of hilar tumor, and high Mayo Adhesive Probability score; the regression coefficients were 1.81, 2.79, and 1.34, respectively. All <jats:italic>p</jats:italic>‐values were ≤.03. The duration of the three‐dimensional‐printed model consultation was significantly related to the complexity of the arterial structure (≥4 branches) and the presence of hilar tumor; the regression coefficients were 21.6, and 29.0 s, respectively. All <jats:italic>p</jats:italic>‐values were &lt;.01.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>During robot‐assisted partial nephrectomy, a three‐dimensional‐printed model would be helpful in cases with a complex arterial structure or hilar tumor.</jats:p></jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Purpose</jats:title> <jats:p>Standardized uptake values (SUVs) derived from <jats:sup>18</jats:sup>F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography are a crucial parameter for identifying tumors or abnormalities in an organ. Moreover, exploring ways to improve the identification of tumors or abnormalities using a statistical measurement tool is important in clinical research. Therefore, we developed a fully automatic method to create a personally normalized Z-score map of the liver SUV.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>The normalized Z-score map for each patient was created using the SUV mean and standard deviation estimated from blood-test-derived variables, such as alanine aminotransferase and aspartate aminotransferase, as well as other demographic information. This was performed using the least absolute shrinkage and selection operator (LASSO)-based estimation formula. We also used receiver operating characteristic (ROC) to analyze the results of people with and without hepatic tumors and compared them to the ROC curve of normal SUV.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>A total of 7757 people were selected for this study. Of these, 7744 were healthy, while 13 had abnormalities. The area under the ROC curve results indicated that the anomaly detection approach (0.91) outperformed only the maximum SUV (0.89). To build the LASSO regression, sets of covariates, including sex, weight, body mass index, blood glucose level, triglyceride, total cholesterol, γ-glutamyl transpeptidase, total protein, creatinine, insulin, albumin, and cholinesterase, were used to determine the SUV mean, whereas weight was used to determine the SUV standard deviation.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>The Z-score normalizes the mean and standard deviation. It is effective in ROC curve analysis and increases the clarity of the abnormality. This normalization is a key technique for effective measurement of maximum glucose consumption by tumors in the liver.</jats:p> </jats:sec>

Objectives: To evaluate the zero-shot performance of Segment Anything Model 2 (SAM 2) in 3D segmentation of abdominal organs in CT scans, and to investigate the effects of prompt settings on segmentation results. Materials and Methods: In this retrospective study, we used a subset of the TotalSegmentator CT dataset from eight institutions to assess SAM 2's ability to segment eight abdominal organs. Segmentation was initiated from three different z-coordinate levels (caudal, mid, and cranial levels) of each organ. Performance was measured using the Dice similarity coefficient (DSC). We also analyzed the impact of "negative prompts," which explicitly exclude certain regions from the segmentation process, on accuracy. Results: 123 patients (mean age, 60.7 \pm 15.5 years; 63 men, 60 women) were evaluated. As a zero-shot approach, larger organs with clear boundaries demonstrated high segmentation performance, with mean DSCs as follows: liver 0.821 \pm 0.192, right kidney 0.862 \pm 0.212, left kidney 0.870 \pm 0.154, and spleen 0.891 \pm 0.131. Smaller organs showed lower performance: gallbladder 0.531 \pm 0.291, pancreas 0.361 \pm 0.197, and adrenal glands, right 0.203 \pm 0.222, left 0.308 \pm 0.234. The initial slice for segmentation and the use of negative prompts significantly influenced the results. By removing negative prompts from the input, the DSCs significantly decreased for six organs. Conclusion: SAM 2 demonstrated promising zero-shot performance in segmenting certain abdominal organs in CT scans, particularly larger organs. Performance was significantly influenced by input negative prompts and initial slice selection, highlighting the importance of optimizing these factors.

This study aimed to explore the relationship between thyroid-stimulating hormone (TSH) elevation and the baseline computed tomography (CT) density and volume of the thyroid. We examined 86 cases with new-onset hypothyroidism (TSH &gt; 4.5 IU/mL) and 1071 controls from a medical check-up database over 5 years. A deep learning-based thyroid segmentation method was used to assess CT density and volume. Statistical tests and logistic regression were employed to determine differences and odds ratios. Initially, the case group showed a higher CT density (89.8 vs. 81.7 Hounsfield units (HUs)) and smaller volume (13.0 vs. 15.3 mL) than those in the control group. For every +10 HU in CT density and −3 mL in volume, the odds of developing hypothyroidism increased by 1.40 and 1.35, respectively. Over the course of the study, the case group showed a notable CT density reduction (median: −8.9 HU), whereas the control group had a minor decrease (−2.9 HU). Thyroid volume remained relatively stable for both groups. Higher CT density and smaller thyroid volume at baseline are correlated with future TSH elevation. Over time, there was a substantial and minor decrease in CT density in the case and control groups, respectively. Thyroid volumes remained consistent in both cohorts.

The generation of synthetic medical records using Generative Adversarial Networks (GANs) is becoming crucial for addressing privacy concerns and facilitating data sharing in the medical domain. In this paper, we introduce a novel method to create synthetic hybrid medical records that combine both image and non-image data, utilizing an auto-encoding GAN (alphaGAN) and a conditional tabular GAN (CTGAN). Our methodology encompasses three primary steps: I) Dimensional reduction of images in a private dataset (pDS) using the pretrained encoder of the {\alpha}GAN, followed by integration with the remaining non-image clinical data to form tabular representations; II) Training the CTGAN on the encoded pDS to produce a synthetic dataset (sDS) which amalgamates encoded image features with non-image clinical data; and III) Reconstructing synthetic images from the image features using the alphaGAN's pretrained decoder. We successfully generated synthetic records incorporating both Chest X-Rays (CXRs) and thirteen non-image clinical variables (comprising seven categorical and six numeric variables). To evaluate the efficacy of the sDS, we designed classification and regression tasks and compared the performance of models trained on pDS and sDS against the pDS test set. Remarkably, by leveraging five times the volume of sDS for training, we achieved classification and regression results that were comparable, if slightly inferior, to those obtained using the native pDS. Our method holds promise for publicly releasing synthetic datasets without undermining the potential for secondary data usage.

OBJECTIVE: To determine a standardized cutoff value for abnormal 18F-fluorodeoxyglucose (FDG) accumulation in the thyroid gland. METHODS: Herein, 7013 FDG-positron emission tomography (PET)/computed tomography (CT) scans were included. An automatic thyroid segmentation method using two U-nets (2D- and 3D-U-net) was constructed; mean FDG standardized uptake value (SUV), CT value, and volume of the thyroid gland were obtained from each participant. The values were categorized by thyroid function into three groups based on serum thyroid stimulating hormone levels. Thyroid function and mean SUV with increments of 1 were analyzed, and risk for thyroid dysfunction was calculated. Thyroid dysfunction detection ability was examined using a machine learning method (Lightgbm) with age, sex, height, weight, CT value, volume, and mean SUV as explanatory variables. RESULTS: Mean SUV was significantly higher in females with hypothyroidism. Almost 98.9% of participants in the normal group had mean SUV <2 and 93.8% participants with mean SUV <2 had normal thyroid function. The hypothyroidism group had more cases with mean SUV ≥2. The relative risk of having abnormal thyroid function was 4.6 with mean SUV ≥2. The sensitivity and specificity for detecting thyroid dysfunction using Lightgbm were 14.5% and 99%, respectively. CONCLUSIONS: Mean SUV ≥2 was strongly associated with abnormal thyroid function in this large cohort, indicating that mean SUV with FDG-PET/CT can be used as a criterion for thyroid evaluation. Preliminarily, this study shows the potential utility of detecting thyroid dysfunction based on imaging findings.

<h4>Introduction</h4>This study aimed to evaluate whether it is useful for junior physicians to use a three-dimensional (3D) kidney model when evaluating the R.E.N.A.L. nephrometry score.<h4>Materials and methods</h4>An expert and four urology residents retrospectively evaluated the R.E.N.A.L. nephrometry scores of 64 renal tumors (62 patients) that underwent robot-assisted partial nephrectomy at our hospital. The expert evaluated 64 R.E.N.A.L. nephrometry scores with computed tomography (CT), whereas four residents evaluated 32 cases using CT alone and the other 32 cases using CT and a 3D kidney model. The consistency between the expert and residents was assessed by Cohen's kappa score. Patient-specific 3D kidney models were created in a gird style using a 3D printer based on CT or magnetic resonance imaging of the patient.<h4>Results</h4>For all four residents, the accuracy of the overall R.E.N.A.L. nephrometry score was significantly higher with the 3D model and CT than with CT alone (P < .001). Regarding the individual components of the R.E.N.A.L. nephrometry score, the accuracy rates of "E," "N," "A," and "L" scores were higher with the 3D model and CT than with the CT alone (P = .020-.089).<h4>Conclusion</h4>Patient-specific 3D-printed kidney models could improve the resident's understanding of the renal tumor complexity and could be an important educational tool for residents.

Decidualization can originate in ovarian endometrioma by elevated serum progesterone levels during pregnancy, which mimics malignancy on ultrasonography. Moreover, decidualized ovarian endometrioma may rupture and cause acute abdominal pain during pregnancy. Magnetic resonance imaging (MRI) is reportedly useful in differentiating decidualized ovarian endometriomas from malignancies. However, to our knowledge, serial MRI of decidualized ovarian endometrioma before and after rupture has not been reported. Herein, we report the case of a 39-year-old woman with a ruptured decidualized ovarian endometrioma in which serial MRI was useful for adequate management. She had a history of right ovarian endometrioma. Transvaginal ultrasonography at 20 weeks of gestation showed the known right ovarian endometrioma with mural nodules that were not evident before pregnancy. MRI for further evaluation showed ovarian endometrioma with mural nodules with signals similar to those of the placenta. Based on the MRI findings, we diagnosed a decidualized ovarian endometrioma. At 27 weeks of gestation, she complained of sudden abdominal pain, for which MRI was performed. MRI showed disappearance of the ovarian endometrioma and bloody ascites, based on which we diagnosed a ruptured ovarian endometrioma. The abdominal pain subsided immediately, and a conservative observational treatment approach was taken. At 37 weeks of gestation, right ovarian cystectomy was performed simultaneously with an elective cesarean section, which revealed a ruptured decidualized ovarian endometrioma. Our findings demonstrate that the accurate diagnosis of a ruptured decidualized ovarian endometrioma on serial MRI can contribute to its management.

Ectopic adrenocortical tissue can arise along the path of embryonic migration, such as the celiac axis, broad ligament, adnexa of the testis, and spermatic cord. Occasionally, ectopic adrenocortical tissues undergo marked hyperplasia and develop into ectopic adrenocortical adenomas. This report describes the case of a 60-year-old man who was incidentally found to have a lipid-containing mass with early enhancement and delayed washout in the right renal hilum. A renal cell carcinoma was suspected, and robot-assisted partial nephrectomy was performed, but the final diagnosis was an ectopic adrenocortical adenoma. We should include ectopic adrenocortical adenoma in the differential diagnosis when we find a lipid-containing tumor adjacent to the kidney.

The definition of sarcopenia assessed by computed tomography (CT) varies among different reports, and few studies have examined the effect of muscle mass loss on the prognosis of post-hematopoietic cell transplantation (HCT). We retrospectively evaluated 172 patients who underwent an initial allogeneic HCT for acute leukemia at our institution. They were divided into 3 groups according to muscle mass measured at the third lumbar vertebra as assessed by CT. Patients with low muscle mass had a worse performance status, higher comorbidity index and higher disease risk. There was a significant difference in 2-year overall survival between the 3 groups, and worse overall survival (OS) was associated with lower muscle mass (p = 0.005). Muscle mass loss did not affect non-relapse mortality (p = 0.238) but was significantly associated with relapse (p = 0.067). Pre-transplant muscle mass loss may therefore reflect a poor prognosis for the primary disease.

Liver cirrhosis is frequently complicated by spontaneous portosystemic shunt (SPSS) due to portal hypertension. Shunt embolization is considered when symptoms related to SPSSs are refractory to endoscopic and/or medical therapies. However, little information is available on the treatment of patients with multiple and large SPSS. We report a successfully managed case in which patient with such SPSS received two embolization procedures within 6 months. A 57-year-old man with alcoholic liver cirrhosis was transferred to our hospital due to a ruptured gastric varix. CT examination showed gastrorenal and splenorenal shunts of 8 mm and 11 mm in diameter, respectively. In addition, multiple hepatocellular carcinomas (HCCs) were noted. First, balloon-occluded retrograde transvenous obliteration (BRTO) was performed for the gastrorenal shunt, resulting in the disappearance of the varix, followed by transcatheter arterial chemoembolization (TACE) for HCCs. However, the hepatic encephalopathy worsened after the BRTO and TACE, and the splenorenal shunt enlarged to 18 mm in diameter. Although the shunt was tortuous and had another drainage vein, we completed the embolization for the shunt using metallic coils without any events. The patient's hepatic encephalopathy and hepatic function were ameliorated after embolization for the splenorenal shunt, and the patient was free from hepatic encephalopathy.

<jats:p>Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a disorder characterized by pustular skin lesions and osteoarticular lesions. Mandibular involvement of SAPHO syndrome is clinically rare, and it is difficult to reach a diagnosis of SAPHO syndrome from only mandibular manifestations. This report describes the case of a 26-year-old woman who presented with mandibular osteitis. Orthopantomogram and computed tomography showed sclerotic change of the right body of the mandible with periosteal reaction without odontogenic infection, which suggested the possibility of SAPHO syndrome. Detailed medical interview found that she had a history of palmoplantar pustulosis treated at a local dermatology clinic and additional bone scintigraphy showed diffuse increased uptake in the right mandible, as well as in the sternum and the sternocostoclavicular joints. She was eventually diagnosed as having SAPHO syndrome. We should consider SAPHO syndrome when we encounter a patient with mandibular osteitis of unknown etiology.</jats:p>