Practical Guide to VI-RADS: MRI Protocols, Lesion Characterization, and Pitfalls.

Urothelial carcinoma is the most common type of bladder cancer (BC), accounting for approximately 90% of all cases. Evaluating the depth of tumor invasion in the bladder wall (tumor staging) is essential for determining the treatment and prognosis in patients with BC. Neoadjuvant therapy followed by radical cystectomy is the most common treatment of localized muscle-invasive BC (MIBC). Therefore, it is vital to differentiate non-MIBC from MIBC. Transurethral resection of bladder tumor (TURBT) is the reference standard to determine the extent of tumor invasion into the bladder wall through tissue sampling. However, this diagnostic and therapeutic method may not adequately sample the muscularis propria, leading to a higher risk of residual disease, early recurrence, and tumor understaging in approximately 50% of patients during the initial TURBT. Multiparametric MRI can overcome some of the limitations of TURBT when evaluating BC, particularly regarding tumor staging. In this context, the Vesical Imaging Reporting and Data System (VI-RADS) classification was developed to establish standards for bladder multiparametric MRI and interpretation. It uses a 5-point scale to assess the likelihood of detrusor muscle invasion. T2-weighted MR images are particularly useful as an initial guide, especially for categories 1-3, while the presence of muscular invasion is determined with diffusion-weighted and dynamic contrast-enhanced sequences. Diffusion-weighted imaging takes precedence as the dominant method when optimal image quality is achieved. The presence of a stalk or a thickened inner layer and no evidence of interruption of the signal intensity of the muscular layer are central for predicting a low likelihood of muscle invasion. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Hoegger in this issue.

VI-RADS score system - A primer for urologists.

Bladder cancer (BCa) is one of the most common cancers worldwide and is also considered to be one of the most relapsing and aggressive neoplasms. About 30% of patients will present with muscle invasive disease, which is associated with a higher risk for metastatic disease. The aim of this article is to review the state of art imaging in Radiology, while providing a complete guide to urologists, with case examples, for the rationale of the development of the Vesical Imaging Reporting and Data System (VI-RADS), a scoring system emphasizing a standardized approach to multiparametric Magnetic Resonance Imaging (mpMRI) acquisition, interpretation, and reporting for BCa. Also, we examine relevant external validation studies and the consolidated literature of mpMRI for bladder cancer. In addition, this article discusses some of the potential clinical implications of this scoring system for disease management and follow-up.

An international expert opinion statement on the utility of PET/MR for imaging of skeletal metastases.

BACKGROUND: MR is an important imaging modality for evaluating musculoskeletal malignancies owing to its high soft tissue contrast and its ability to acquire multiparametric information. PET provides quantitative molecular and physiologic information and is a critical tool in the diagnosis and staging of several malignancies. PET/MR, which can take advantage of its constituent modalities, is uniquely suited for evaluating skeletal metastases. We reviewed the current evidence of PET/MR in assessing for skeletal metastases and provided recommendations for its use. METHODS: We searched for the peer reviewed literature related to the usage of PET/MR in the settings of osseous metastases. In addition, expert opinions, practices, and protocols of major research institutions performing research on PET/MR of skeletal metastases were considered. RESULTS: Peer-reviewed published literature was included. Nuclear medicine and radiology experts, including those from 13 major PET/MR centers, shared the gained expertise on PET/MR use for evaluating skeletal metastases and contributed to a consensus expert opinion statement. [18F]-FDG and non [18F]-FDG PET/MR may provide key advantages over PET/CT in the evaluation for osseous metastases in several primary malignancies. CONCLUSION: PET/MR should be considered for staging of malignancies where there is a high likelihood of osseous metastatic disease based on the characteristics of the primary malignancy, hight clinical suspicious and in case, where the presence of osseous metastases will have an impact on patient management. Appropriate choice of tumor-specific radiopharmaceuticals, as well as stringent adherence to PET and MR protocols, should be employed.

Profile of Articles Published in AJR From 2014 to 2018 and Potential Association With Bibliometric Parameters.

OBJECTIVE. The purpose of this study was to assess the profile of articles published in the American Journal of Roentgenology (AJR) and potential associations with bibliometric indexes over a 5-year period. MATERIALS AND METHODS. Citable documents published from 2014 to 2018 were retrieved from the Journal Citation Reports database. Six bibliometric indexes were assessed. The following article parameters were retrieved: type, subspecialty (17 topics covered by AJR), origin, and title. Differences between groups were assessed by t test, ANOVA, Kruskal-Wallis test, or chi-square test. Citability was assessed by regression analysis. RESULTS. After exclusions, 2210 articles were considered citable and included in the analyses. Most of the metrics improved slightly, except for the Eigenfactor score and article influence score, which decreased. Original articles were preponderant; AJR published significantly more review articles than did three other general radiology journals. The mean number of citations per year of original articles (2.03 ± 2.18) was significantly larger than that of review articles (2.06 ± 2.47) (p = .02). The mean number of citations per year was significantly higher for articles with mixed-origin authorship (3.12 ± 3.19) than for articles with American (2.02 ± 2.17) or non-American (1.93 ± 2.26) authors only (p < .001). The distributions of mean number of citations per year among subspecialties differed significantly (p = .001). Articles on abdominal, musculoskeletal, pediatric, and women's imaging were more frequently cited. Multivariate regression analysis showed that subspecialty and presence of acronyms or initialisms in the title were the only independent predictors of citability (both, p = .001). CONCLUSION. The main AJR bibliometric indexes increased slightly from 2014 to 2018, except for those from the Eigenfactor Project. The presence of acronyms or initialisms in the title and subspecialty were the only independent predictors of citability.

Pelvic floor muscles after prostate radiation therapy: morpho-functional assessment by magnetic resonance imaging, surface electromyography and digital anal palpation.

AIM: To evaluate the radiotherapy (RT) effect in the pelvic floor muscles (PFM) function in men with prostate cancer (PC). MATERIALS AND METHODS: A cross-sectional study included three groups of patients with PC and RT indication: 1) Pre-RT group: evaluated before the beginning of RT; 2) Acute group: evaluated between six months and one year after RT; 3) Late Group: evaluated between two and a half years and four years post-RT. PFM assessment was divided into: a) functional assessment through the digital anal palpation (Modified Oxford Scale) and surface electromyography (sEMG) with anal probe; b) anatomical assessment by pelvic magnetic resonance imaging (MRI) with thickness measurements of levator ani muscle and pelvic specific parameters at rest and under Valsalva maneuver. We used Student t test, considering as significant p <0.05. RESULTS: Thirty-three men were assessed: Pre-RT (n=12); Acute (n=10) and Late (n=11) groups. PFM functional assessment showed Late group with lower electromyographic activity, especially in the sustained contractions when compared to the Pre-RT (p=0.003) and Acute groups (p=0.006). There was no significant difference between groups in MRI. CONCLUSION: PFM functional assessment showed a decrease in sEMG activity in the Late group post-RT. Most of the sample (72.7%) did not know how to actively contract the PFM or had a weak voluntary contraction when assessed by digital anal palpation. Also, these patients presented higher prevalence of pelvic complaints. No changes were observed in the morpho-functional parameters evaluated by MRI, except the measurement of the membranous urethra length when comparing Pre-RT Group and Acute and Late Groups.

Prevalence of Vas Deferens Calcifications on Abdominal CT Examinations and Association With Systemic Conditions.

OBJECTIVE. The purpose of this study was to describe the prevalence of vas deferens (VD) calcifications on abdominal CT examinations and the associations between VD calcifications and several systemic conditions. MATERIALS AND METHODS. The CT examinations of male patients from January 2010 to December 2011 were retrospectively reviewed. After exclusions, the records of 1915 consecutively identified patients were analyzed. Five readers, 3rd- and 4th-year radiology residents, recorded the presence and laterality of VD calcifications and of vascular calcifications presumed due to atherosclerosis. A sixth reader parsed the patient records for diagnoses of type 2 diabetes mellitus (DM) and chronic kidney disease (CKD). RESULTS. The mean age of the entire sample population was 52.9 ± 18.9 years (range, 1-93 years). The mean age of patients with VD calcifications was 59.3 ± 12.0 (SD) years and of the group without VD calcifications was 52.9 ± 19.1 years (p = 0.17). The prevalence of VD calcification was 1.61% (31 patients): 21 (67.7%) of the patients had bilateral calcification; seven (22.6%), right-sided only; and three, (9.7%) left-sided. The frequency of DM was 28.8% (551/1915), of CKD was 7.58% (150/1915), and of atherosclerosis, 60.4% (1156/1915). The mean caliber of calcified VDs was 5.31 ± 1.29 mm versus 3.63 ± 0.63 mm for patients without calcification or any chronic condition (p < 0.0001). Among age, atherosclerosis, DM, and CKD in univariate regression analysis, only DM was associated with VD calcification (p = 0.006). However, because age (p = 0.063) and atherosclerosis (p = 0.057) were close to significant, they were included in the multivariate analysis, which also showed only DM associated with VD calcification (odds ratio, 2.14 ± 0.85). CONCLUSION. In the large cohort in this study, the prevalence of VD calcification was 1.61%. VD calcification was strongly associated with DM. The pathologic implications of VD calcification remain unclear and warrant further investigation in prospective longitudinal studies.

Histogram Analysis of Adrenal Lesions With a Single Measurement for 10th Percentile: Feasibility and Incremental Value for Diagnosing Adenomas.

OBJECTIVE: Our purpose was to assess whether histogram analysis of adrenal lesions from a single measurement of mean attenuation and SD, using a threshold of 10% of negative voxels, can replace voxel counting while maintaining diagnostic accuracy. MATERIALS AND METHODS: In a 4-year period, 325 adrenal lesions were detected on CT examinations of 308 consecutive patients. After exclusions, 91 patients with 108 lesions, including 20 malignant lesions and 88 adenomas (defined by histologic results or follow-up), were enrolled. Two observers retrospectively measured lesion size, mean attenuation value, and SD attenuation value and generated a pixel histogram. The 10th percentile (P10) was obtained from the conventional histogram analysis and was also calculated from the following formula: P10 = mean attenuation - (1.282 × SD). Diagnostic accuracies of the mean attenuation criterion, histogram analysis, and calculated 10th percentile were compared. RESULTS: The study group was composed of 74 patients with 88 adenomas and 17 patients with 20 malignant lesions, including seven adrenocortical carcinomas and 13 metastases; 93.1% of histograms showed normal distribution. The correlation between histogram analysis and calculated 10th percentile was 0.9827 and 0.9843 for reader 1 and 2 (p < 0.00001 for both). For both readers, sensitivity and specificity of the mean attenuation analysis were 65.9% (95% CI, 55.0-75.7%) and 100.0% (95% CI, 83.2-100%). The sensitivity and specificity of histogram analysis and calculated 10th percentile were the same, 87.5% (95% CI, 78.7-93.6%) and 95.0% (95% CI, 75.1-99.8%), for both readers. The increment increase in sensitivity was significant (p < 0.001), whereas the decrease in specificity was not (p = 0.15). CONCLUSION: For most adrenal lesions, the pixel attenuation has a gaussian distribution, allowing estimation of 10th percentile with a single measurement. The accuracy of histogram analysis and calculated 10th percentile outperformed the mean attenuation as a diagnostic criterion for nonfunctioning adenomas.

Incremental value of MRI for preoperative penile cancer staging.

PURPOSE: To evaluate the incremental value of magnetic resonance imaging (MRI), compared to clinical examination, for penile cancer (PC) local staging. MATERIALS AND METHODS: Twenty-five consecutive patients with histologically proven PC were evaluated prospectively. MRI staging was performed on 1.5 and 3.0T scanners using high-resolution T2 -weighted and postcontrast T1 -weighted images. Two blinded observers interpreted MR images. Clinical local staging was performed by experienced urologists. The pathology report was used as the standard of reference. RESULTS: The interobserver agreement for MRI staging, using a kappa test for T-staging was moderate, 0.52 (95% confidence interval [CI] = 0.24-0.78), P = 0.001, although a high correlation for N-staging, 0.72 (95% CI = 0.42-1.00), P = 0.001, was detected. Clinical staging was correct in 52.0% (13/25) of patients. After pathological staging, five (20.0%) lesions were upstaged and seven (28.0%) lesions were downstaged compared to clinical examination. MRI accurately defined T-staging in 18/25 lesions (72.0%). After pathologic staging, five (20.0%) were upstaged and two downstaged (8.0%), compared to MRI. Fifteen patients were submitted to inguinal and pelvic lymphadenectomy and considered for comparison of accuracy of nodal staging by physical examination and MRI. Clinical staging accurately staged 7/15 patients (46.7%). After histopathologic analysis, six cases had nodal staging upgraded and two cases were downgraded. MRI correctly staged 13/15 (86.7%). Using a chi-square for comparison, differences in proportion of corrected staging between clinical examination and MRI were not significant for T-staging (P = 0.14), but were significant for nodal staging (P = 0.02). CONCLUSION: According to our results, MRI improves local staging of PC patients, particularly for those with limited physical examination. LEVEL OF EVIDENCE: 1 J. Magn. Reson. Imaging 2017;45:118-124.

ABCG2 is a potential marker of tumor-initiating cells in breast cancer.

The existence of tumor-initiating cells (TICs) within solid tumors has been hypothesized to explain tumor heterogeneity and resistance to cancer therapy. In breast cancer, the expression of CD44 and CD24 and the activity of aldehyde dehydrogenase 1 (ALDH1) can be used to selectively isolate a cell population enriched in TICs. However, the ideal marker to identify TICs has not been established. The aim of this study was to evaluate the expression of novel potential markers for TIC in breast carcinoma. We prospectively analyzed the expression of CD44, CD24, ABCG2, and CXCR4, and the activity of ALDH1 by using flow cytometry in 48 invasive ductal carcinomas from locally advanced and metastatic breast cancer patients who were administered primary chemotherapy. A mammosphere assay was employed in 30 samples. The relationship among flow cytometric analyses, ABCG2 gene expression, and clinical and pathological responses to therapy was analyzed. The GSE32646 database was analyzed in silico to identify genes associated with tumors with low and high ABCG2 expression. We observed that the presence of ABCG2(+) cells within the primary tumor was the only marker to predict the formation of mammospheres in vitro (R (2) = 0.15, p = 0.029). Quantitative polymerase chain reaction (qPCR) revealed a positive correlation between ABCG2 expression and the presence of ABCG2(+) cells within the primary tumor. The expression of ABCG2 was predictive of the response to neoadjuvant chemotherapy in our experiments and in the GSE32646 dataset (p = 0.04 and p = 0.002, respectively). The in silico analysis demonstrated that ABCG2(Up) breast cancer samples have a slower cell cycle and a higher expression of membrane proteins but a greater potential for chromosomal instability, metastasis, immune evasion, and resistance to hypoxia. Such genetic characteristics are compatible with highly aggressive and resistant tumors. Our results support the hypothesis that the presence of ABCG2(+) cells in breast carcinomas is a marker of resistance to chemotherapy, and based on in vitro assays and the genetic profile, we show, for the first time, that ABCG2 protein can be used as an independent marker for TIC identification in breast cancer.

Low yield of chemical shift MRI for characterization of adrenal lesions with high attenuation density on unenhanced CT.

PURPOSE: To investigate the threshold unenhanced CT density of adrenal nodules at which further evaluation with chemical shift MRI is unlikely to be definitive and therefore not helpful in further characterizing some indeterminate adrenal lesions. METHODS: Retrospective evaluation of 44 adrenal lesions imaged with unenhanced CT and chemical shift MRI and followed for at least 1 year. Qualitative and quantitative assessment of signal loss on chemical shift MRI was performed. Adenomas were diagnosed if the lesion measured equal or less than 10 HU on unenhanced CT; on MRI a SI index greater than 16.5% or adrenal:spleen chemical shift ratio less than 0.71 was considered diagnostic of adenoma. RESULTS: 31.8% (14/44), 47.7% (21/44), and 20.5% (9/44) of the adrenal lesions had an unenhanced CT attenuation density ≤10, 10-30, and >30 HU. Adrenal lesions with an unenhanced CT density 10-30 and >30 HU had a 76.2% (16/21) and a 33.3% (3/9) chance of being categorized as an adenoma using MRI SI index, respectively. CONCLUSIONS: Adrenal lesions with unenhanced attenuation CT density >30 HU had a 66.6% of remaining indeterminate even after evaluation with chemical shift MRI. ADVANCES IN KNOWLEDGE: Chemical shift MRI is reasonable for evaluating adrenal lesions with an unenhanced CT attenuation density less than 30 HU. The likelihood of chemical shift MRI detecting signal loss in lesions CT density greater than 30 HU, however, is low.

Lung cancer screening in Brazil: recommendations from the Brazilian Society of Thoracic Surgery, Brazilian Thoracic Association, and Brazilian College of Radiology and Diagnostic Imaging.

Although lung cancer (LC) is one of the most common and lethal tumors, only 15% of patients are diagnosed at an early stage. Smoking is still responsible for more than 85% of cases. Lung cancer screening (LCS) with low-dose CT (LDCT) reduces LC-related mortality by 20%, and that reduction reaches 38% when LCS by LDCT is combined with smoking cessation. In the last decade, a number of countries have adopted population-based LCS as a public health recommendation. Albeit still incipient, discussion on this topic in Brazil is becoming increasingly broad and necessary. With the aim of increasing knowledge and stimulating debate on LCS, the Brazilian Society of Thoracic Surgery, the Brazilian Thoracic Association, and the Brazilian College of Radiology and Diagnostic Imaging convened a panel of experts to prepare recommendations for LCS in Brazil. The recommendations presented here were based on a narrative review of the literature, with an emphasis on large population-based studies, systematic reviews, and the recommendations of international guidelines, and were developed after extensive discussion by the panel of experts. The following topics were reviewed: reasons for screening; general considerations about smoking; epidemiology of LC; eligibility criteria; incidental findings; granulomatous lesions; probabilistic models; minimum requirements for LDCT; volumetric acquisition; risks of screening; minimum structure and role of the multidisciplinary team; practice according to the Lung CT Screening Reporting and Data System; costs versus benefits of screening; and future perspectives for LCS.

The imaging and pathological features of a mucinous tubular and spindle cell carcinoma of the kidney: a case report.

A mucinous tubular and spindle cell carcinoma (MTSCC) is a rare and recently described kidney neoplasm with distal nephron differentiation. It can affect patients of all ages and is more prevalent among women. In this case report, we present a 50-year-old woman who had a renal mass, which was accidently discovered during an investigation for chronic anemia. The final diagnosis of MTSCC was made after the lesion was removed and a pathology work-up was performed. The clinical, pathological and imaging findings of this rare neoplasm are described in this report.