Radiomics Analysis of Magnetic Resonance Proton Density Fat Fraction for the Diagnosis of Hepatic Steatosis in Patients With Suspected NonAlcoholic Fatty Liver Disease

Background@#This study aimed to assess the diagnostic feasibility of radiomics analysis based on magnetic resonance (MR)-proton density fat fraction (PDFF) for grading hepatic steatosis in patients with suspected non-alcoholic fatty liver disease (NAFLD). @*Methods@#This retrospective study included 106 patients with suspected NAFLD who underwent a hepatic parenchymal biopsy. MR-PDFF and MR spectroscopy were performed on all patients using a 3.0-T scanner. Following whole-volume segmentation of the MRPDFF images, 833 radiomic features were analyzed using a commercial program. Radiologic features were analyzed, including median and mean values of the multiple regions of interest and variable clinical features. A random forest regressor was used to extract the important radiomic, radiologic, and clinical features. The model was trained using 20 repeated 10-fold cross-validations to classify the NAFLD steatosis grade. The area under the receiver operating characteristic curve (AUROC) was evaluated using a classifier to diagnose steatosis grades. @*Results@#The levels of pathological hepatic steatosis were classified as low-grade steatosis (grade, 0–1; n = 82) and high-grade steatosis (grade, 2–3; n = 24). Fifteen important features were extracted from the radiomic analysis, with the three most important being wavelet-LLL neighboring gray tone difference matrix coarseness, original first-order mean, and 90th percentile. The MR spectroscopy mean value was extracted as a more important feature than the MR-PDFF mean or median in radiologic measures. Alanine aminotransferase has been identified as the most important clinical feature. The AUROC of the classifier using radiomics was comparable to that of radiologic measures (0.94 ± 0.09 and 0.96 ± 0.08, respectively). @*Conclusion@#MR-PDFF-derived radiomics may provide a comparable alternative for grading hepatic steatosis in patients with suspected NAFLD.

Metastatic Renal Cell Carcinoma Manifesting as a Gastric Polyp on CT: A Case Report and Literature Review

Gastric metastasis from renal cell carcinoma (RCC) is extremely rare, occurring in 0.2% of all RCC cases. Owing to its low prevalence, metachronous gastric metastasis from RCC may be underdiagnosed, and the imaging findings have not been well-established. Herein we present a case of metastatic RCC manifesting as a gastric polyp in a 70-year-old female along with a literature review on the imaging findings of gastric metastases from RCC. In patients presenting with gastric hyper-enhancing polypoid masses, metastasis from RCC should be considered as a differential diagnosis.

A Rare Case of Small Bowel Undifferentiated Pleomorphic Sarcoma: Imaging Findings on CT and Magnetic Resonance Enterography

Gastrointestinal tract involvement in undifferentiated pleomorphic sarcoma (UPS) is extremely rare. To the authors' knowledge, only 21 cases of primary small bowel UPS have been reported in the literature available in English. Reported CT findings in primary small bowel UPS have been nonspecific, and MRI findings have been reported in only one case. The present article describes a case involving a 72-year-old male with histologically confirmed primary UPS arising from the ileum, focusing on both CT and magnetic resonance enterography findings. On CT, primary small bowel UPS was noted as a heterogeneously enhanced small bowel mass without obstruction. Magnetic resonance enterography revealed heterogeneous intermediate T1 and T2 signal intensity, with hemorrhagic or necrotic foci within the mass and heterogeneous enhancement. The differential diagnosis included malignant gastrointestinal tumor; however, the prognosis of UPS is worse, with higher incidences of extra-abdominal metastasis.

Radiologic Findings of Renal Schwannoma: A Case Report and Literature Review

Schwannoma is a benign nerve sheath tumor that involves Schwann cells mostly found in the head, neck, posterior mediastinum and extremities. Schwannoma develops rarely in the retroperitoneum; thus, renal schwannoma is extremely uncommon. Differentiation of renal schwannoma from renal cell carcinoma is difficult with radiologic analysis. A few cases of these tumors have been reported in literature, and little has been described regarding imaging appearances. In this study, we present a rare case of a renal schwannoma, resembling renal cell carcinoma, with radiological correlations.

Progressive Transformation of Germinal Centers in Presacral Space: MRI Findings and Literature Review

Progressive transformation of germinal centers (PTGC) is an atypical feature seen in lymph nodes with unknown pathogenesis. PTGC most commonly presents in adolescent and young adult males as solitary painless lymphadenopathy with various durations. Cervical nodes are the most commonly involved ones while involvements of axillary and inguinal nodes are less frequent. PTGC develops extremely rarely in other locations. We report a rare case of solitary mass present in the presacral space. The mass as subsequently proven to be PTGC. To the best of our knowledge, PTGC in the presacral space has not been previously reported in the literature.

Hepatic Lesions that Mimic Metastasis on Radiological Imaging during Chemotherapy for Gastrointestinal Malignancy: Recent Updates

During chemotherapy in patients with gastrointestinal malignancy, the hepatic lesions may occur as chemotherapy-induced lesions or tumor-associated lesions, with exceptions for infectious conditions and other incidentalomas. Focal hepatic lesions arising from chemotherapy-induced hepatopathies (such as chemotherapy-induced sinusoidal injury and steatosis) and tumor-associated eosinophilic abscess should be considered a mimicker of metastasis in patients with gastrointestinal malignancy. Accumulating evidence suggests that chemotherapy for gastrointestinal malignancy in the liver has roles in both the therapeutic effects for hepatic metastasis and injury to the non-tumor bearing hepatic parenchyma. In this article, we reviewed the updated concept of chemotherapy-induced hepatopathies and tumor-associated eosinophilic abscess in the liver, focusing on the pathological and radiological findings. Awareness of the causative chemo-agent, pathophysiology, and characteristic imaging findings of these mimickers is critical for accurate diagnosis and avoidance of unnecessary exposure of the patient to invasive tissue-based diagnosis and operations.

MR Imaging Findings of Tamoxifen-associated Uterine Adenosarcoma: Report of Two Cases

Adenosarcoma of the uterus is a rare biphasic tumor containing benign glandular epithelial and malignant mesenchymal components. The tumor has been reported to be associated with antiestrogen therapy, particularly tamoxifen, but there have been a few case reports with MRI. We present two cases of MRI findings of uterine adenosarcoma after antiestrogen therapy, tamoxifen and toremifene in breast cancer patients. The tumor presents as a large polypoid mass occupying the endometrial cavity, and may protrude into the vagina. On MRI, the tumor typically shows solid components with scattered small cysts and heterogeneous enhancement. These findings are not significantly different from conventional adenosarcoma.

MRI Findings of Obstructed Hemivagina and Ipsilateral Renal Agenesis (OHVIRA syndrome) with a Blind Megaureter: Case Report

Obstructed hemivagina and ipsilateral renal anomaly (OHVIRA) syndrome is an uncommon congenital abnormality of the female urogenital tract characterized by the triad of uterine didelphys, obstructed hemivagina, and ipsilateral renal agenesis. A 13-year-old female presented with acute lower abdominal pain. Magnetic resonance imaging (MRI) revealed uterine didelphys, hematometrocolpos, obstructed hemivagina, and right ipsilateral agenesis, consistent with OHVIRA syndrome. Also, a well-defined mass with fluid signal intensity, mimicking adnexal neoplasm was seen in the right lower pelvic cavity adjacent to the posterior wall of the bladder. Vaginal septotomy and drainage of hematometrocolpos were done initially, but unilateral hysterectomy was later performed to relieve the patient's symptoms. The cystic mass in the right lower pelvic cavity was also excised and confirmed as a blind megaureter.

MR Imaging of Anoperineal Tuberculous Abscess: A Case Report

Anoperineal tuberculosis is a rare extrapulmonary form of the disease and may present as abscess. We report a case of anoperineal tuberculous abscess, which showed low signal intensity on T1-weighted images, high signal intensity on T2-weighted images and diffusion restriction on diffusion weighted images.

Ultrasonographic and MRI Findings of Extratesticular Epidermal Cyst of the Scrotum: A Case Report

An extratesticular scrotal epidermal cyst is a very rare condition and few cases of extratesticular scrotal epidermal cyst with radiologic findings have been reported. Therefore, we report here on a rare case with ultrasonographic and MRI findings. A 70-year-old male patient was admitted with a palpable mass in the left scrotum. A well-defined heterogeneous hypoechoic mass with scattered echogenic reflectors in the scrotum was identified on ultrasonography. The cystic mass showed high signal intensity on T2-weighted images, low signal intensity on T1-weighted images, and diffusion restriction on diffusion weighted images.

Female External Genitalia and Urethra on MR Imaging: Optimal Pulse Sequence and Comparison of Anatomy in Premenopausal and Postmenopausal Women

PURPOSE: To describe normal anatomy and compare the differences of external genital organs and urethra on MR imaging in pre- and postmenopausal women. MATERIALS AND METHODS: A total of 19 pre- and 18 postmenopausal healthy women underwent pelvis MR imaging at 1.5 T. Two radiologists retrospectively scored and compared the image quality of female external genitalia and urethra on axial T2-weighted images (T2WI) and axial fat-suppressed contrast-enhanced T1-weighted images (FSCE-T1WI) by using Wilcoxon signed ranks test. The radiologists compared the wall thickness or size of external genital organs and urethra on FSCE-T1WI between two groups by using Student t test. RESULTS: Image quality was better with FSCE-T1WI than with T2WI in all subjects (p < 0.05). The vestibular bulb, clitoris and labium minor were more clearly visualized on FSCE-T1WI in premenopausal subjects rather than in postmenopausal subjects (p < 0.05). The urethra had a target-like appearance with three layers in premenopausal and postmenopausal subjects. Postmenopausal subjects were observed to have significantly smaller vaginal wall thickness, urethral wall thickness and vestibular bulb width than premenopausal subjects (p < 0.05). CONCLUSION: The anatomy and morphologic changes of female external genital organs and urethra were well discernible on FSCE-T1WI.

Ultrasonographic Findings of Fibrous Pseudotumor Arising from the Tunica Vaginalis Testis: A Case Report

Fibrous pseudotumors are rare, benign fibroproliferative tumor-like lesions in the scrotum, and they most commonly arise from the tunica vaginalis testis (75%). There have been few reported cases of the fibrous pseudotumor of the tunica vaginalis testis with the radiologic findings, so we report on this rare case with focusing on the ultrasonographic findings. A 20-year-old man was admitted with a palpable mass in the right scrotum. On ultrasonography, multiple nodules were seen together with posterior shadowing along the inner surface of the scrotal wall. Fibrous pseudotumor arising from the tunica vaginalis testis was pathologically confirmed after surgical excision.

Percutaneous Intervention in Axillary Loop-Configured Arteriovenous Grafts for Chronic Hemodialysis Patients

OBJECTIVE: The purpose of this study was to evaluate the fistulographic features of malfunctioning axillary loop-configured arteriovenous grafts and the efficacy of percutaneous interventions in failed axillary loop-configured arteriovenous grafts. MATERIALS AND METHODS: Ten patients with axillary loop-configured arteriovenous grafts were referred for evaluation of graft patency or upper arm swelling. Fistulography and percutaneous intervention, including thrombolysis, percutaneous transluminal angioplasty and stent placement, were performed. Statistical analysis of the procedure success rate and the primary and secondary patency rates was done. RESULTS: Four patients had graft related and subclavian venous stenosis, two patients had graft related stenosis and another four patients had subclavian venous stenosis only. Sixteen sessions of interventional procedures were performed in eight patients (average: 2 sessions / patient) until the end of follow-up. An interventional procedure was not done in two patients with central venous stenosis. The overall procedure success rate was 69% (11 of 16 sessions). The post-intervention primary and secondary patency rates were 50% and 63% at three months, 38% and 63% at six months and 25% and 63% at one year, respectively. CONCLUSION: Dysfunctional axillary loop-configured arteriovenous grafts almost always had subclavian venous and graft-related stenosis. Interventional treatments are helpful to overcome this and these treatments are expected to play a major role in restoring and maintaining the axillary loop-configured arteriovenous loop grafts.

The Incidence and Anatomy of Accessory Pudendal Arteries as Depicted on Multidetector-Row CT Angiography: Clinical Implications of Preoperative Evaluation for Laparoscopic and Robot-Assisted Radical Prostatectomy

OBJECTIVE: To help preserve accessory pudendal arteries (APAs) and to ensure optimal postoperative sexual function after a laparoscopic or robot-assisted radical prostatectomy, we have evaluated the incidence of APAs as detected on multidetector-row CT (MDCT) angiography and have provided a detailed anatomical description. MATERIALS AND METHODS: The distribution of APAs was evaluated in 121 consecutive male patients between February 2006 and July 2007 who underwent 64-channel MDCT angiography of the lower extremities. We defined an APA as any artery located within the periprostatic region running parallel to the dorsal vascular complex. We also subclassified APAs into lateral and apical APAs. Two radiologists retrospectively evaluated the origin, course and number of APAs; the final APA subclassification based on MDCT angiography source data was determined by consensus. RESULTS: We identified 44 APAs in 36 of 121 patients (30%). Two distinct varieties of APAs were identified. Thirty-three APAs (75%) coursed near the anterolateral region of the prostatic apex, termed apical APAs. The remaining 11 APAs (25%) coursed along the lateral aspect of the prostate, termed lateral APAs. All APAs originated from the internal obturator artery and iliac artery or a branch of the iliac artery such as the inferior vesical artery. The majority of apical APAs arose from the internal obturator artery (84%). Seven patients (19%) had multiple APAs. CONCLUSION: APAs are more frequently detected by the use of MDCT angiography than as suggested by previous surgical studies. The identification of APAs on MDCT angiography may provide useful information for the surgical preservation of APAs during a laparoscopic or robot-assisted radical prostatectomy.