Fully Automated Deep Learning Model to Detect Clinically Significant Prostate Cancer at MRI.

Background Multiparametric MRI can help identify clinically significant prostate cancer (csPCa) (Gleason score ≥7) but is limited by reader experience and interobserver variability. In contrast, deep learning (DL) produces deterministic outputs. Purpose To develop a DL model to predict the presence of csPCa by using patient-level labels without information about tumor location and to compare its performance with that of radiologists. Materials and Methods Data from patients without known csPCa who underwent MRI from January 2017 to December 2019 at one of multiple sites of a single academic institution were retrospectively reviewed. A convolutional neural network was trained to predict csPCa from T2-weighted images, diffusion-weighted images, apparent diffusion coefficient maps, and T1-weighted contrast-enhanced images. The reference standard was pathologic diagnosis. Radiologist performance was evaluated as follows: Radiology reports were used for the internal test set, and four radiologists' PI-RADS ratings were used for the external (ProstateX) test set. The performance was compared using areas under the receiver operating characteristic curves (AUCs) and the DeLong test. Gradient-weighted class activation maps (Grad-CAMs) were used to show tumor localization. Results Among 5735 examinations in 5215 patients (mean age, 66 years ± 8 [SD]; all male), 1514 examinations (1454 patients) showed csPCa. In the internal test set (400 examinations), the AUC was 0.89 and 0.89 for the DL classifier and radiologists, respectively (P = .88). In the external test set (204 examinations), the AUC was 0.86 and 0.84 for the DL classifier and radiologists, respectively (P = .68). DL classifier plus radiologists had an AUC of 0.89 (P < .001). Grad-CAMs demonstrated activation over the csPCa lesion in 35 of 38 and 56 of 58 true-positive examinations in internal and external test sets, respectively. Conclusion The performance of a DL model was not different from that of radiologists in the detection of csPCa at MRI, and Grad-CAMs localized the tumor. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Johnson and Chandarana in this issue.

Application of high-density 2D receiver coil arrays for improved SNR in prostate MRI.

PURPOSE: To study if adaptive image receive (AIR) receiver coil elements can be configured into a 2D array with high (>45% by diameter) element-to-element overlap, allowing improved SNR at depth (0.7-1.5× element diameter) versus conventional (20%) overlap. METHODS: An anterior array composed of twenty 10-cm diameter elements with 45% overlap arranged into a 4 × 5 grid and a similar 3 × 7 twenty-one-element posterior array were constructed. SNR and g-factor were measured in a pelvic phantom using the new high-density (HD) arrays (41 total elements) and compared to vendor AIR-based arrays (30 total elements) with conventional overlap. T2-weighted fast-spin-echo (T2SE) images acquired using both arrays were compared in 20 subjects. SNR was estimated in vivo. Results were compared blindly by three uroradiologists using a five-point scale. Images using the HD arrays were also compared to a set of images acquired over a range of acceleration factors (R = 2.0, 2.5, 3.0) with the conventional arrays. RESULTS: SNR within the phantom was on average 15% higher for R = 1.0, 1.5, and 2.0 using the HD arrays. Across the 20 subjects SNR within the prostate was 11% higher and assessed radiologically as significantly higher (p < 0.001) for the HD versus conventional arrays. At all acceleration factors the new HD arrays outperformed the conventional arrays (p ≤ 0.01), allowing increased R for similar SNR. CONCLUSION: AIR elements can be configured into 2D arrays with high (45%) element-to-element overlap, consistently providing increased SNR at depth versus arrays with conventional (20%) overlap. The SNR improvement allows increased acceleration in T2SE prostate MRI.

Natural language processing pipeline to extract prostate cancer-related information from clinical notes.

OBJECTIVES: To develop an automated pipeline for extracting prostate cancer-related information from clinical notes. MATERIALS AND METHODS: This retrospective study included 23,225 patients who underwent prostate MRI between 2017 and 2022. Cancer risk factors (family history of cancer and digital rectal exam findings), pre-MRI prostate pathology, and treatment history of prostate cancer were extracted from free-text clinical notes in English as binary or multi-class classification tasks. Any sentence containing pre-defined keywords was extracted from clinical notes within one year before the MRI. After manually creating sentence-level datasets with ground truth, Bidirectional Encoder Representations from Transformers (BERT)-based sentence-level models were fine-tuned using the extracted sentence as input and the category as output. The patient-level output was determined by compilation of multiple sentence-level outputs using tree-based models. Sentence-level classification performance was evaluated using the area under the receiver operating characteristic curve (AUC) on 15% of the sentence-level dataset (sentence-level test set). The patient-level classification performance was evaluated on the patient-level test set created by radiologists by reviewing the clinical notes of 603 patients. Accuracy and sensitivity were compared between the pipeline and radiologists. RESULTS: Sentence-level AUCs were ≥ 0.94. The pipeline showed higher patient-level sensitivity for extracting cancer risk factors (e.g., family history of prostate cancer, 96.5% vs. 77.9%, p < 0.001), but lower accuracy in classifying pre-MRI prostate pathology (92.5% vs. 95.9%, p = 0.002) and treatment history of prostate cancer (95.5% vs. 97.7%, p = 0.03) than radiologists, respectively. CONCLUSION: The proposed pipeline showed promising performance, especially for extracting cancer risk factors from patient's clinical notes. CLINICAL RELEVANCE STATEMENT: The natural language processing pipeline showed a higher sensitivity for extracting prostate cancer risk factors than radiologists and may help efficiently gather relevant text information when interpreting prostate MRI. KEY POINTS: When interpreting prostate MRI, it is necessary to extract prostate cancer-related information from clinical notes. This pipeline extracted the presence of prostate cancer risk factors with higher sensitivity than radiologists. Natural language processing may help radiologists efficiently gather relevant prostate cancer-related text information.

Imaging of Upper Tract Urothelial Carcinoma.

Upper tract urothelial carcinoma (UTUC) originates in the renal pelvis or ureters and typically affects elderly patients, with its incidence increasing over the past few decades. UTUC is a distinct clinical entity with more aggressive clinical behavior than that of lower tract urothelial carcinoma. Due to the significant challenge of acquiring an adequate tissue sample for biopsy, comprehensive risk stratification is required for treatment planning, including radical nephroureterectomy and kidney-sparing management. Imaging plays an important integrated role in risk assessment along with endoscopy and pathologic examination. Lifelong surveillance is required after treatment due to the high incidence of recurrent and metachronous tumors. Lynch syndrome is a frequently unrecognized genetic disorder associated with UTUC that warrants specific attention in patient management. UTUC may manifest with diverse imaging findings, including filling defects, wall thickening, and mass-forming lesions. CT urography is the preferred modality for diagnosis and staging or restaging of UTUC, with numerous technical variations. Efforts have been made to optimize image quality and radiation exposure. Due to its poor sensitivity for small lesions, use of MR urography is limited to special clinical scenarios (eg, when patients have contraindications to iodinated contrast agents). Fluorine 18 fluorodeoxyglucose PET helps to detect metastatic lesions. Image-guided biopsy may be considered for uncertain lesions. Radiologists need to be familiar with the imaging findings and their differential diagnoses. ©RSNA, 2024 Supplemental material is available for this article.

MRI in Adult Patients with Active and Inactive Implanted MR-conditional, MR-nonconditional, and Other Devices.

Active implanted medical devices (AIMDs) enable therapy and patient monitoring by way of electrical activity and typically have a battery and electrical leads. The most common types of AIMDs include cardiac implantable electronic devices (CIEDs), spinal cord stimulators, deep brain stimulators, bone growth or fusion stimulators, other neurostimulators, and drug infusion pumps. As more patients with AIMDs undergo MRI, it is important to consider the safety of patients who have these implanted devices during MRI. The authors review the physics concepts related to MRI safety, such as peak spatial gradient magnetic field, specific absorption rate, root mean square value of the effective magnetic component of the transmitted RF pulse, and gradient slew rate, as well as the parameters necessary to remain within safety limits. The roles of MRI safety personnel, as set forth by the International Society of Magnetic Resonance in Medicine, are emphasized. In addition, the relevant information provided in vendor manuals is reviewed, with a focus on how to obtain relevant up-to-date information. The radiologist should be able to modify protocols to meet safety requirements, address possible alternatives to MRI, and weigh the potential benefits of MRI against the potential risks. A few more advanced topics, such as fractured or abandoned device leads and patients with multiple implanted medical devices, also are addressed. Recommended workflows for MRI in patients with implanted medical devices are outlined. It is important to implement an algorithmic MRI safety process, including a review of the MRI safety information; patient screening; optimal imaging; and monitoring patients before, during, and after the examination. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Shetty et al in this issue.

Imaging of Perirenal and Intrarenal Lymphatic Vessels: Anatomy-based Approach.

The lymphatic system (or lymphatics) consists of lymphoid organs and lymphatic vessels. Despite the numerous previously published studies describing conditions related to perirenal and intrarenal lymphoid organs in the radiology literature, the radiologic findings of conditions related to intrarenal and perirenal lymphatic vessels have been scarcely reported. In the renal cortex, interlobular lymphatic capillaries do not have valves; therefore, lymph can travel along the primary route toward the hilum, as well as toward the capsular lymphatic plexus. These two lymphatic pathways can be opacified by contrast medium via pyelolymphatic backflow at CT urography, which reflects urinary contrast agent leakage into perirenal lymphatic vessels via forniceal rupture. Pyelolymphatic backflow toward the renal hilum should be distinguished from urinary leakage due to urinary injury. Delayed subcapsular contrast material retention via pyelolymphatic backflow, appearing as hyperattenuating subcapsular foci on CT images, mimics other subcapsular cystic diseases. In contrast to renal parapelvic cysts originating from the renal parenchyma, renal peripelvic cysts are known to be of lymphatic origin. Congenital renal lymphangiectasia is mainly seen in children and assessed and followed up at imaging. Several lymphatic conditions, including lymphatic leakage as an early complication and acquired renal lymphangiectasia as a late complication, are sometimes identified at imaging follow-up of kidney transplant. Lymphangiographic contrast material accumulation in the renal hilar lymphatic vessels is characteristic of chylo-urinary fistula. Chyluria appears as a fat-layering fluid-fluid level in the urinary bladder or upper urinary tract. Recognition of the anatomic pathway of tumor spread via lymphatic vessels at imaging is of clinical importance for accurate management at oncologic imaging. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

High plasma concentration of tenofovir alafenamide in people living with HIV with ABCB1 genetic variants.

OBJECTIVES: We aimed to analyze the relationships between single nucleotide polymorphisms in the ATP-binding cassette transporter B1 (ABCB1) and G2 (ABCG2) genes and plasma concentrations of tenofovir alafenamide (TAF), tenofovir (TFV), and emtricitabine (FTC). METHODS: We recruited 10 people living with HIV receiving once-daily treatment with a single tablet containing TAF (25 mg), FTC (200 mg), and bictegravir (50 mg). Peripheral blood samples were collected at 0, 1, 2, 3, 4, 6, 8, 12, and 24 h after administration. Plasma concentrations of TAF, TFV, and FTC were quantified using liquid chromatography-tandem mass spectrometry. Genotyping for allelic variants of ABCB1, including 1236C > T (rs1128503), 2677 G > T/A (rs2032582), 3435C > T (rs1045642), 4036 A > G (rs3842) and ABCG2 421C > A (rs2231142), was performed using TaqMan Drug Metabolism Assays. RESULTS: None of the genotypes for ABCB1 1236C > T, 2677 G > T/A, 3435C > T, and ABCG2 421C > A exhibited correlations with plasma concentrations of TAF, TFV, and FTC. In contrast, individuals with the ABCB1 4036 AG genotype (188.7 ng/mL, n = 3) exhibited a significantly higher mean peak plasma concentration of TAF than those with the ABCB1 4036 AA genotype (67.7 ng/mL, n = 7) (p = 0.0167). However, these genotypes did not affect the elimination of terminal half-lives of TAF. CONCLUSIONS: The allelic variant ABCB1 4036 A > G is associated with reduced protein expression and function of ABCB1. Individuals with this genetic variant exhibited significantly high peak plasma concentrations of TAF, potentially due to the reduced expression of efflux transporters in the intestines linked to this variant.

Autopsy of tetanus with foot gangrene as portal of entry.

Non-traumatic chronic skin lesions are the second most common cause of tetanus. Herein, we describe an 85-year-old woman who presented with a chronically infected skin lesion. She developed tetanus while in hospital and died of respiratory failure, after refusing mechanical ventilation. Routine immunization against tetanus began in Japan during 1968; hence many people born before 1968 are unvaccinated. Mortality due to tetanus is high and the proportion with protective antibodies is low in older adults. Therefore, we recommend tetanus vaccination for older persons in Japan who have chronic skin lesions and have never been vaccinated.

Local radiotherapy for chemotherapy-refractory Kaposi's sarcoma in an HIV-infected patient: A case report and literature review.

Human immunodeficiency virus-associated Kaposi's sarcoma (HIV-KS) is a well-documented vascular tumor with a pathogenesis involving human herpesvirus-8 (HHV-8) infection. While antiretroviral therapy (ART) and chemotherapy are effective for treating most KS cases, some become refractory. In this report, we present a case of a 58-year-old man with refractory HIV-KS treated with ART and chemotherapy. Chemotherapy was eventually discontinued due to an adverse reaction, and the patient presented with painful plantar lesions that impaired ambulation. With the exclusion of visceral metastases, localized radiotherapy was administered, which resulted in significant cosmetic and functional improvements. The patient regained ambulation and lived independently, receiving additional radiotherapy as needed. This case underscores the potential use of radiotherapy for the treatment of ART-resistant KS, particularly when the patient is unresponsive to conventional chemotherapy. It also highlights the need for future research in this area.

An overlapping case of IgG4-related disease and systemic lupus erythematosus treated with belimumab: a case-based review.

IgG4-related disease (IgG4-RD) is a systemic condition in which IgG4+ plasma cell infiltration and fibrosis cause organ swelling and lead to diverse clinical manifestations. Although IgG4-RD typically responds to glucocorticoids (GCs), relapse during tapering occurs and an early GC-sparing approach might therefore be beneficial. Systemic lupus erythematosus (SLE) is a chronic inflammatory disease with multiple symptoms that is also treated with GCs as a first-line therapy. Recently, belimumab, a recombinant human IgG-1λ monoclonal antibody that inhibits B-cell activating factor, was approved, but reports of use for IgG4-RD are scarce. Here, we present a rare case of IgG4-RD complicated with SLE which was successfully treated with belimumab. A 67-year-old man was diagnosed with IgG4-RD based on a high serum IgG4 level and histopathological findings. Furthermore, he had pericardial effusion on echocardiography, and laboratory tests revealed thrombocytopenia, autoimmune hemolysis, positive anti-nuclear antibodies, positive anti-DNA antibodies, and hypocomplementemia. These data led to an SLE diagnosis. Treatment was started with prednisolone at 40 mg/day, plus hydroxychloroquine, which initially improved both the SLE and IgG4-RD symptoms. During the GC tapering, belimumab was added and clinical symptoms resolved completely. Our case and the literature review summarize reported rare overlapping cases of IgG4-RD and SLE and suggest that belimumab is a promising candidate for the treatment of IgG4-RD.

Re-evaluation of the reduced heart weights in male rats in a 28-day oral repeated-dose toxicity study of tetramethylammonium hydroxide.

We recently conducted a detailed hazard assessment of tetramethylammonium hydroxide (TMAH), a priority chemical substance under the Japan Chemical Substances Control Law. During this assessment, there was debate regarding the reduced heart weight observed in the treated male groups in the 28-day rat oral repeated-dose toxicity study. This finding was not observed in females in this study and in both sexes of oral toxicity studies for tetramethylammonium chloride (TMAC) or tetramethylammonium hydrogen phthalate (TMAHP). Unpublished individual data from the oral TMAH developmental and reproductive toxicity (DART) screening study were also obtained; no effect on heart weight was observed. In addition, background data on rat heart weight from six 28-day oral toxicity studies conducted in the same facility, year, strain, age, and breeder as the TMAH study were obtained from the Japan Existing Chemical Substances Database (JECDB). These investigations suggest that the statistically significant lower heart weight in the treated males in the 28-day toxicity study is likely caused by an incidental skewing of individuals with heavier heart weights toward control male groups and is not due to TMAH treatment. Thus, it is worthwhile to include as much relevant data as possible to confirm or refute unexpected findings in toxicity studies.

Clinical importance of anti-Ro52 antibody for polymyositis and dermatomyositis.

OBJECTIVES: To clarify clinical features of anti-Ro52 antibody (Ab)-positive polymyositis (PM)/dermatomyositis (DM). PATIENTS AND METHODS: We retrospectively examined clinical features and status of anti-Ro52 Ab in patients with PM/DM admitted at the University of Tsukuba Hospital between January 2019 and February 2023. We compared anti-Ro52 Ab-positive and -negative groups. RESULTS: A total of 40 patients were selected and analyzed. Median age at diagnosis was 61.5 (48.8-69.3) years and 34 cases were female. Twenty-three cases were PM and 17 cases were DM (including 6 clinically amyopathic dermatomyositis: CADM). Twenty-two cases were positive for anti-Ro52 Ab, 14 for anti-ARS Ab, and 6 for anti-MDA5 Ab. Interstitial lung disease (ILD) was detected in 29 cases, 9 of which were rapidly progressive. Glucocorticoid (GC)-resistant cardiomyopathy was detected in 6 cases, malignancy in 3 cases, and Sjögren's syndrome (SS) in 4 cases. Of the 22 anti-Ro52 Ab positive cases, only 3 were single-positive and the remaining 19 cases simultaneously had other autoantibodies. Comparing the anti-Ro52 Ab-positive and -negative groups, the frequencies of anti-ARS Ab positivity (63.6% vs. 0%), ILD (95.5% vs. 44.4%), GC-resistant cardiomyopathy (27.3% vs. 0%), concomitant use of immunosuppressants (95.5% vs. 55.6%), and levels of C-reactive protein (CRP) were significantly higher in the anti-Ro52 Ab-positive group (p<0.05). The frequencies of PM/DM, positivity of anti-MDA5 Ab, malignancies, and SS were comparable between groups. CONCLUSION: Anti-Ro52 Ab were frequently positive in PM/DM and anti-Ro52 Ab-positive patients showed significantly higher rates of anti-ARS Ab positivity and ILD, GC-resistant cardiomyopathy, concomitant use of immunosuppressants, and higher levels of CRP. Anti-Ro52 Ab may be useful as a severity marker in PM/DM.

Model-based image reconstruction with wavelet sparsity regularization for through-plane resolution restoration in T2 -weighted spin-echo prostate MRI.

PURPOSE: The purpose is to develop a model-based image-reconstruction method using wavelet sparsity regularization for maintaining restoration of through-plane resolution but with improved retention of SNR versus linear reconstruction using Tikhonov (TK) regularization in high through-plane resolution (1 mm) T2 -weighted spin-echo (T2SE) images of the prostate. METHODS: A wavelet sparsity (WS)-regularized image reconstruction was developed that takes as input a set of ≈80 overlapped 3-mm-thick slices acquired using a T2SE multislice scan and typically 30 coil elements. After testing in contrast and resolution phantoms and calibration in 6 subjects, the WS reconstruction was evaluated in 16 consecutive prostate T2SE MRI exams. Results reconstructed with nominal 1-mm thickness were compared with those from the TK reconstruction with the same raw data. Results were evaluated radiologically. The ratio of magnitude of prostate signal to periprostatic muscle signal was used to assess the presence of noise reduction. Technical performance was also compared with a commercial 3D-T2SE sequence. RESULTS: The new WS reconstruction was assessed as superior statistically to TK for overall SNR, contrast, and multiple evaluation criteria related to sharpness while retaining the high (1 mm) through-plane resolution. Wavelet sparsity tended to provide improved overall diagnostic quality versus TK, but not significantly so. In all 16 studies, the prostate-to-muscle signal ratio increased. CONCLUSIONS: Model-based WS-regularized reconstruction consistently provides improved SNR in high (1 mm) through-plane resolution images of prostate T2SE MRI versus linear reconstruction using TK regularization.

Decreased prostate MRI cancer detection rate due to moderate to severe susceptibility artifacts from hip prosthesis.

OBJECTIVES: To evaluate the impact of susceptibility artifacts from hip prosthesis on cancer detection rate (CDR) in prostate MRI. MATERIALS AND METHODS: This three-center retrospective study included prostate MRI studies for patients without known prostate cancer between 2017 and 2021. Exams with hip prosthesis were searched on MRI reports. The degree of susceptibility artifact on diffusion-weighted images was retrospectively categorized into mild, moderate, and severe (> 66%, 33-66%, and < 33% of the prostate volume are evaluable) by blind reviewers. CDR was defined as the number of exams with Gleason score ≥7 detected by MRI (PI-RADS ≥3) divided by the total number of exams. For each artifact grade, control exams without hip prosthesis were matched (1:6 match), and CDR was compared. The degree of CDR reduction was evaluated with ratio, and influential factors were evaluated by expanding the equation. RESULTS: Hip arthroplasty was present in 548 (4.8%) of the 11,319 MRI exams. CDR of the cases and matched control exams for each artifact grade were as follows: mild (n = 238), 0.27 vs 0.25, CDR ratio = 1.09 [95% CI: 0.87-1.37]; moderate (n = 143), 0.18 vs 0.27, CDR ratio = 0.67 [95% CI: 0.46-0.96]; severe (n = 167), 0.22 vs 0.28, CDR ratio = 0.80 [95% CI: 0.59-1.08]. When moderate and severe artifact grades were combined, CDR ratio was 0.74 [95% CI: 0.58-0.93]. CDR reduction was mostly attributed to the increased frequency of PI-RADS 1-2. CONCLUSION: With moderate to severe susceptibility artifacts from hip prosthesis, CDR was decreased to 74% compared to the matched control. CLINICAL RELEVANCE STATEMENT: Moderate to severe susceptibility artifacts from hip prosthesis may cause a non-negligible CDR reduction in prostate MRI. Expanding indications for systematic prostate biopsy may be considered when PI-RADS 1-2 was assigned. KEY POINTS: • We proposed cancer detection rate as a diagnostic performance metric in prostate MRI. • With moderate to severe susceptibility artifacts secondary to hip arthroplasty, cancer detection rate decreased to 74% compared to the matched control. • Expanding indications for systematic prostate biopsy may be considered when PI-RADS 1-2 is assigned.

Malignant Neoplasms of the Penis with Radiologic and Pathologic Correlation.

Penile malignancy is the third most common male-specific genitourinary malignancy, with squamous cell carcinoma representing the most common histologic type. Squamous cell carcinoma is an epithelial malignancy, frequently developing from the mucosal surfaces of the foreskin, glans, and coronal sulcus and manifesting as a distal infiltrative or ulcerated mass. This typically occurs in men from the 6th to 8th decades of life, and risk factors include human papillomavirus, phimosis, presence of foreskin and poor hygiene, chronic inflammatory conditions such as lichen sclerosus, trauma, and smoking. Primary urethral malignancies including urothelial carcinoma and adenocarcinoma can occur but may lack this distal predilection. Sarcoma, melanoma, leukemia or lymphoma, and metastatic disease are less common sources of penile malignancy. Because of the sensitive nature of penile malignancies, there may be delays in seeking care and in subsequent diagnosis. Recently, the staging guidelines for penile cancer have been updated concurrently with a shift toward more penile-preserving therapies, which have led to a larger role of imaging in diagnosis, staging, and treatment planning for penile malignancies. A variety of imaging modalities may play a role in the identification and staging of penile malignancy, including an increased use of MRI for local staging of tumors, CT and PET/CT for identification of nodal and distant disease, and US for image-guided biopsy. The authors discuss an imaging approach to a spectrum of penile malignancies, with an emphasis on radiologic and pathologic correlation and how knowledge of normal tissue types and anatomic structures can aid in the diagnosis and staging of these tumors. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Imaging of Castleman Disease.

Castleman disease (CD) is a group of rare and complex lymphoproliferative disorders that can manifest in two general forms: unicentric CD (UCD) and multicentric CD (MCD). These two forms differ in clinical manifestation, imaging appearances, treatment options, and prognosis. UCD typically manifests as a solitary enlarging mass that is discovered incidentally or after development of compression-type symptoms. MCD usually manifests acutely with systemic symptoms including fever and weight loss. As a whole, CD involves lymph nodes throughout the chest, neck, abdomen, pelvis, and axilla and can have a wide variety of imaging appearances. Most commonly, lymph nodes or masses in UCD occur in the chest, classically with well-defined borders, hyperenhancement, and possible characteristic patterns of calcification and/or feeding vessels. Lymph nodes affected by MCD, while also hyperenhancing, tend to involve multiple nodal chains and manifest alongside anasarca or hepatosplenomegaly. The polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) subtype of MCD may demonstrate lytic or sclerotic osseous lesions in addition to features typical of MCD. Since a diagnosis of CD based solely on imaging findings is often not possible, pathologic confirmation with core needle biopsy and/or surgical excision is necessary. Nevertheless, imaging plays a crucial role in supporting the diagnosis of CD, guiding appropriate regions for biopsy, and excluding other potential causes or mimics of disease. CT is frequently the initial imaging technique used in evaluating potential CD. MRI and PET play important roles in thoroughly evaluating the disease and determining its extent, especially the MCD form. Complete surgical excision is typically curative for UCD. MCD usually requires systemic therapy. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Urinary Bladder Masses, Rare Subtypes, and Masslike Lesions: Radiologic-Pathologic Correlation.

Urinary bladder masses are commonly encountered in clinical practice, with 95% arising from the epithelial layer and rarer tumors arising from the lamina propria, muscularis propria, serosa, and adventitia. The extent of neoplastic invasion into these bladder layers is assessed with multimodality imaging, and the MRI-based Vesical Imaging Reporting and Data System is increasingly used to aid tumor staging. Given the multiple layers and cell lineages, a diverse array of pathologic entities can arise from the urinary bladder, and distinguishing among benign, malignant, and nonneoplastic entities is not reliably feasible in most cases. Pathologic assessment remains the standard of care for classification of bladder masses. Although urothelial carcinoma accounts for most urinary bladder malignancies in the United States, several histopathologic entities exist, including squamous cell carcinoma, adenocarcinoma, melanoma, and neuroendocrine tumors. Furthermore, there are variant histopathologic subtypes of urothelial carcinoma (eg, the plasmacytoid variant), which are often aggressive. Atypical benign bladder masses are diverse and can have inflammatory or iatrogenic causes and mimic malignancy. © RSNA, 2022 Online supplemental material is available for this article.

Streptobacillus notomytis Bacteremia after Exposure to Rat Feces.

To determine the source of Streptobacillus notomytis bacteremia in a woman in Japan with signs of rat-bite fever, we examined rat feces from her home. After culture and PCR failed to identify the causative organism in the feces, next-generation sequencing detected Streptobacillus spp., illustrating this procedure's value for identifying causative environmental organisms.

Long-Term Risk of Clinical Progression Utilizing Magnetic Resonance Imaging Findings of Locally Recurrent Prostate Cancer in Patients with Biochemical Recurrence following Radical Prostatectomy.

PURPOSE: Our goal was to evaluate the long-term prognostic value of magnetic resonance imaging of the prostatectomy bed in patients with biochemical recurrence after radical prostatectomy for prostate cancer. MATERIALS AND METHODS: Men with biochemical recurrence after radical prostatectomy who were studied by prostatectomy bed magnetic resonance imaging for suspected local recurrence were retrospectively evaluated. Locally recurrent tumors were noted and measured from imaging reports. Patients with nodal/bone lesions at the time of imaging were excluded. Kaplan-Meier and Cox regression analyses were used to assess systemic progression-free and prostate cancer-specific survival. RESULTS: A total of 896 men were enrolled and the imaging positive and negative groups for local recurrent tumor consisted of 441 and 455 men, respectively. On univariate analysis, preoperative prostate specific antigen (p=0.02), clinical tumor stage (p=0.006), pathological Gleason score from prostatectomy (p=0.02), subsequent salvage radiotherapy (p <0.001), biochemical recurrence to magnetic resonance imaging time interval (p <0.001), age at magnetic resonance imaging (p=0.047) and prostate specific antigen at magnetic resonance imaging (p <0.001) were significantly different between magnetic resonance imaging positive and negative groups. Patients with negative magnetic resonance imaging results had worse systemic progression-free survival rates (p=0.025) and better prostate cancer-specific survival (p=0.016) than those with recurrence. Larger lesion size significantly increased risk of prostate cancer death (hazard ratio: 1.07; p <0.001). On multivariable analysis, pathological Gleason scores ≥7 were independent prognostic factors of systemic progression (p <0.05). CONCLUSIONS: Prostatectomy bed magnetic resonance imaging provides long-term prognostic information for the evaluation of patients with biochemical recurrence after prostatectomy. Post-prostatectomy patients with recurrent lesions on imaging had longer progression-free survival but shorter prostate cancer-specific survival compared to those without lesions. Additionally, those with larger lesions were associated with poorer cancer-specific survival.

CT findings and diagnostic performance of upper urinary tract carcinoma in situ.

OBJECTIVES: To evaluate the CT characteristics and detectability of carcinoma in situ (CIS) of the upper urinary tract. METHODS: Between January 2007 and March 2020, 28 patients (mean age: 73 years, 25 male and 3 female) with 29 pure CIS lesions of the upper urinary tract (i.e., without concomitant non-CIS lesion) who underwent nephroureterectomy were identified. The most recent CT scan performed before ureteroscopy, systemic neoadjuvant chemotherapy, or nephroureterectomy was selected for analysis. Twenty-eight patients without upper tract malignancy were selected as a control group. All images were evaluated for presence of upper urinary tract CIS using confidence levels ranging from 1 to 100 by two radiologists. The confidence level of 75 was used as a cutoff threshold for calculating sensitivity and specificity. RESULTS: The median interval between CT scan and nephroureterectomy was 96 days. The number of true-positive lesions (per-lesion sensitivity) was 41% (12/29) and 52% (15/29) by readers 1 and 2. The true-positive lesion appeared as wall thickening in 83% (10/12) by reader 1 and 80% (12/15) by reader 2, and as a mass in 17% (2/12) by reader 1 and 20% (3/15) by reader 2. All mass-forming lesions were located in the renal collecting system. The per-patient sensitivity and specificity were 42% and 100% in reader 1, and 54% and 96% in reader 2. CONCLUSIONS: The common abnormal finding of pure CIS in the upper urinary tract was wall thickening. Pure CIS could also appear as a mass-forming lesion when it is located in the renal collecting system. KEY POINTS: • The common abnormal finding of pure CIS in the upper urinary tract is wall thickening. Gradually progressive urothelial wall thickening and/or worsening symptoms should raise the suspicion of CIS. • Pure CIS in the upper urinary tract also appears as a mass-forming lesion when it is located in the renal collecting system. • Hydronephrosis and fat stranding play an auxiliary role in detecting pure CIS in the upper urinary tract.