Utility of ADC Values for Differentiating Uterine Sarcomas From Leiomyomas: Systematic Review and Meta-Analysis.

Background: Uterine sarcomas are rare; however, they display imaging features that overlap those of leiomyomas. The potential for undetected uterine sarcomas is clinically relevant because minimally invasive treatment of leiomyomas may lead to cancer dissemination. ADC values have shown potential for differentiating benign and malignant uterine masses. Objective: The purpose of this study was to perform a systematic review of the diagnostic performance of ADC values in differentiating uterine sarcomas from leiomyomas. Evidence acquisition: We searched three electronic databases (MEDLINE, EMBASE, and Cochrane databases) for studies distinguishing uterine sarcomas from leiomyomas using MRI, including ADC, with pathologic tissue confirmation or imaging follow-up as the reference standard. Data extraction and QUADAS-2 quality assessment were performed. Sensitivity and specificity were pooled using hierarchic models, including bivariate and hierarchic summary ROC models. Metaregression was used to assess the impact of various factors on heterogeneity. Evidence synthesis: Twenty-one studies met study inclusion criteria. Pooled sensitivity and specificity were 89% (95% CI, 82-94%) and 86% (95% CI, 78-92%), respectively. Area under the summary ROC curve was 94% (95% CI, 92-96%). Context of ADC interpretation (i.e., standalone vs part of multiparametric MRI [mpMRI]) was the only factor found to account significantly for heterogeneity (p = .01). Higher specificity (95% [95% CI, 92-99%] vs 82% [95% CI, 75-89%]) and similar sensitivity (94% [95% CI, 89-99%] vs 88% [95% CI, 82-93%]) were observed when ADC was evaluated among mpMRI features as compared with standalone ADC assessment. ADC cutoff values ranged (0.87-1.29 × 10-3 mm2/s) but were not associated with statistically different performance (p = .37). Pooled mean ADC values in sarcomas and leiomyomas were 0.904 × 10-3 mm2/s and 1.287 × 10-3 mm2/s, respectively. Conclusion: As part of mpMRI evaluation of uterine masses, mass ADC value less than 0.904 × 10-3 mm2/s may be a useful test-positive threshold for uterine sarcoma, consistent with a prior expert consensus statement. Institutional protocols may influence locally selected ADC values. Clinical Impact: Using ADC as part of mpMRI assessment improves detection of uterine sarcoma, which could influence candidate selection for minimally invasive treatments.

Imaging of Antepartum and Postpartum Hemorrhage.

Severe obstetric hemorrhage is a leading cause of maternal mortality and morbidity worldwide. Major hemorrhage in the antepartum period presents potential risks for both the mother and the fetus. Similarly, postpartum hemorrhage (PPH) accounts for up to a quarter of maternal deaths worldwide. Potential causes of severe antepartum hemorrhage that radiologists should be familiar with include placental abruption, placenta previa, placenta accreta spectrum disorders, and vasa previa. Common causes of PPH that the authors discuss include uterine atony, puerperal genital hematomas, uterine rupture and dehiscence, retained products of conception, and vascular anomalies. Bleeding complications unique to or most frequently encountered after cesarean delivery are also enumerated, including entities such as bladder flap hematomas, rectus sheath and subfascial hemorrhage, and infectious complications of endometritis and uterine dehiscence. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Javitt and Madrazo in this issue.

How We Got Here: The Legacy of Anti-Black Discrimination in Radiology.

Current disparities in the access to diagnostic imaging for Black patients and the underrepresentation of Black physicians in radiology, relative to their representation in the general U.S. population, reflect contemporary consequences of historical anti-Black discrimination. These disparities have existed within the field of radiology and professional medical organizations since their inception. Explicit and implicit racism against Black patients and physicians was institutional policy in the early 20th century when radiology was being developed as a clinical medical field. Early radiology organizations also embraced this structural discrimination, creating strong barriers to professional Black radiologist involvement. Nevertheless, there were numerous pioneering Black radiologists who advanced scholarship, patient care, and diversity within medicine and radiology during the early 20th century. This work remains important in the present day, as race-based health care disparities persist and continue to decrease the quality of radiology-delivered patient care. There are also structural barriers within radiology affecting workforce diversity that negatively impact marginalized groups. Multiple opportunities exist today for antiracism work to improve quality of care and to apply standards of social justice and health equity to the field of radiology. An initial step is to expand education on the disparities in access to imaging and health care among Black patients. Institutional interventions include implementing community-based outreach and applying antibias methodology in artificial intelligence algorithms, while systemic interventions include identifying national race-based quality measures and ensuring imaging guidelines properly address the unique cancer risks in the Black patient population. These approaches reflect some of the strategies that may mutually serve to address health care disparities in radiology. © RSNA, 2023 See the invited commentary by Scott in this issue. Quiz questions for this article are available in the supplemental material.

Bosniak Classification of Cystic Renal Masses, Version 2019: An Update Proposal and Needs Assessment.

Cystic renal cell carcinoma (RCC) is almost certainly overdiagnosed and overtreated. Efforts to diagnose and treat RCC at a curable stage result in many benign neoplasms and indolent cancers being resected without clear benefit. This is especially true for cystic masses, which compared with solid masses are more likely to be benign and, when malignant, less aggressive. For more than 30 years, the Bosniak classification has been used to stratify the risk of malignancy in cystic renal masses. Although it is widely used and still effective, the classification does not formally incorporate masses identified at MRI or US or masses that are incompletely characterized but are highly likely to be benign, and it is affected by interreader variability and variable reported malignancy rates. The Bosniak classification system cannot fully differentiate aggressive from indolent cancers and results in many benign masses being resected. This proposed update to the Bosniak classification addresses some of these shortcomings. The primary modifications incorporate MRI, establish definitions for previously vague imaging terms, and enable a greater proportion of masses to enter lower-risk classes. Although the update will require validation, it aims to expand the number of cystic masses to which the Bosniak classification can be applied while improving its precision and accuracy for the likelihood of cancer in each class.

Active Surveillance of Small (< 4 cm) Bosniak Category 2F, 3, and 4 Renal Lesions: What Happens on Imaging Follow-Up?

OBJECTIVE. The purpose of this study was to determine the percentage of small (< 4 cm) Bosniak category 2F, 3, and 4 lesions that regress during active surveillance. MATERIALS AND METHODS. In this retrospective study, a hospital database was searched from January 1, 2005, through September 9, 2017, for small (< 4 cm) Bosniak category 2F, 3, and 4 lesions studied with initial and follow-up unenhanced and contrast-enhanced CT or MRI. Prospective Bosniak categories were recorded. Two blinded radiologists retrospectively reassigned Bosniak categories to the initial and last follow-up studies. Interreader variability was analyzed. Rates of stability, regression, and progression were calculated and stratified by size. Logistic regression was used to assess the effects of lesion size, lesion growth, and duration of follow-up on the change in Bosniak categories. RESULTS. The search identified 123 patients (85 men, 38 women) with 138 renal lesions (according to the blinded readings, 83 Bosniak category 2F, 37 category 3, and 18 category 4) and followed for 1-12.3 years (median, 2.7 years). Fifty-one percent (70/138) of the lesions were smaller than 2 cm. Eighty-eight percent (73/83) of category 2F lesions were downgraded or remained stable. Forty-five percent (25/55) of category 3 or 4 lesions were downgraded to 2F or lower. Kappa values were 0.94 between the two readers and 0.72-0.76 between the readers and the prospective Bosniak categories. There was no association between initial size, change in size, or duration of follow-up and change in Bosniak category. CONCLUSION. Approximately one-half of small (< 4 cm) Bosniak category 3 and 4 cystic renal lesions were downgraded, and the majority (88%) of small Bosniak category 2F lesions regressed or remained stable during active surveillance. Therefore, small size should be a consideration for conservative management.

MRI-Based Apparent Diffusion Coefficient for Predicting Pathologic Response of Rectal Cancer After Neoadjuvant Therapy: Systematic Review and Meta-Analysis.

OBJECTIVE: The purpose of this study was to assess the use of apparent diffusion coefficient (ADC) during DWI for predicting complete pathologic response of rectal cancer after neoadjuvant therapy. MATERIALS AND METHODS: A systematic review of available literature was conducted to retrieve studies focused on the identification of complete pathologic response of locally advanced rectal cancer after neoadjuvant chemoradiation, through the assessment of ADC evaluated before, after, or both before and after treatment, as well as in terms of the difference between pretreatment and posttreatment ADC. Pooled mean pretreatment ADC, posttreatment ADC, and Δ-ADC (calculated as posttreatment ADC minus pretreatment ADC divided by pretreatment ADC and multiplied by 100) in complete responders versus incomplete responders were calculated. For each parameter, we also pooled sensitivity and specificity and calculated the area under the summary ROC curve. RESULTS: We found 10 prospective and eight retrospective studies. Overall, pathologic complete response was observed in 22.2% of patients. Pooled mean pretreatment ADC in complete responders was 0.84 × 10-3 mm2/s versus 0.89 × 10-3 mm2/s in incomplete responders (p = 0.33). Posttreatment ADC values were 1.51 × 10-3 mm2/s and 1.29 × 10-3 mm2/s, in complete and incomplete responders, respectively (p = 0.00001). The Δ-ADC percentages were also significantly higher in complete responders than in incomplete responders (59.7% vs 29.7%, respectively, p = 0.016). Pooled sensitivity, specificity, and AUC were 0.743, 0.755, and 0.841 for pretreatment ADC; 0.800, 0.737, and 0.782 for posttreatment ADC; and 0.832, 0.806, and 0.895 for Δ-ADC. CONCLUSION: Use of ADC during DWI is a promising technique for assessment of results of neoadjuvant treatment of rectal cancer.

Frequency and Outcomes of Incidental Breast Lesions Detected on Abdominal MRI Over a 7-Year Period.

OBJECTIVE: Our aim was to evaluate the frequency and outcomes of incidental breast lesions detected on abdominal MRI examinations. MATERIALS AND METHODS: Abdominal MRI reports for 11,462 women imaged at our institution from November 2007 through December 2014 were reviewed to identify those reporting an incidental breast lesion. Available breast imaging and pathology results were assessed to identify outcomes in these lesions. RESULTS: Incidental breast lesions were described in the MRI reports of 292 (3%) patients who underwent abdominal MRI during the study period; breast imaging was recommended for 192 of these 292 (66%) patients. Sixty-three of the 192 (33%) patients for whom follow-up breast imaging was recommended underwent such imaging at our institution. Twenty-one of these 63 (33%) lesions underwent biopsy or surgery; histologic sampling of these lesions yielded seven incidental cancers (invasive ductal, n = 6; invasive lobular, n = 1) and 14 benign diagnoses. Three additional cancers (invasive ductal, n = 2; invasive lobular, n = 1) and three benign diagnoses were discovered at pathology at outside institutions. Of the remaining 165 patients without a histologic diagnosis, the lesions in 95 (58%) patients were presumed to be benign because of stability over time. Seven of the 10 patients with a diagnosis of incidental cancer (age range, 53-86 years; mean ± SD, 67.0 ± 10.6 years) had not undergone screening mammography at our institution. The frequency of incidental breast cancer was 11% of patients subsequently undergoing follow-up breast imaging at our institution, 3% of all patients with reported breast lesions, and 0.09% of patients undergoing abdominal MRI examinations. CONCLUSION: Although incidental breast lesions were rarely detected on abdominal MRI, a considerable number of these lesions were found to represent breast cancer, particularly when leading to a recommendation for follow-up breast imaging. Therefore, it is important for radiologists interpreting abdominal MRI examinations to carefully evaluate for the presence of breast abnormalities.

Approach to Very Small (< 1.5 cm) Cystic Renal Lesions: Ignore, Observe, or Treat?

OBJECTIVE: This article will review the current available literature on the prevalence, behavior, and pathology of very small (< 1.5 cm) cystic renal lesions. A summary of the recommended approach to these very small lesions is provided. CONCLUSION: Limited data exist to guide the management of very small cystic renal lesions. Because most data favor benign or indolent behavior, vigorous workup of the very small cystic renal lesion seems unnecessary.

Follow-up for Bosniak category 2F cystic renal lesions.

PURPOSE: To determine percentage of Bosniak category 2F complex cystic renal masses that progress to malignancy based on serial follow-up studies,and to determine if there are demographic and/or imaging features associated with progression. MATERIALS AND METHODS: This retrospective study was institutional review board-approved with waiver of informed consent. Hospital database system was searched from January 1, 1996, to May 1, 2011, for category 2F cysts studied with contrast agent-enhanced computed tomography or magnetic resonance imaging and followed with serial contrast-enhanced imaging. Demographics of patients and imaging features of lesions that progressed were compared with those that did not. The relationship of these features to progression or stability was assessed by using χ(2), Fisher exact, or Cochran Armitage trend tests. RESULTS: Identified in 144 patients (98 men, 46 women; age range, 31-83 years; average, 63 years) were 156 category 2F lesions. Follow-up studies were from 6 months to 13 years (median, 3.6 years; average, 4.2 years). Nineteen of 156 lesions progressed to category 3 or 4 in 6 months to 3.2 years; 17 lesions (89.5% of those that progressed and 10.9% of initial 2F lesions) were malignant and two were benign. To date, no patients had recurrent or metastatic disease. Men had significant risk for progression to malignancy (P = .003). Of 17 category 2F lesions that progressed to malignancy, 12 were endophytic (P = .02). Category 2F lesions with minimally irregular septa (nine of 17; P= .001) or wall (seven of 17; P = .016), and lesions with indistinct parenchymal interface (nine of 17; P < .001) were associated with progression to cancer. A multilobulated border was not associated with progression (P = .999). CONCLUSION: Based on this study, 10.9% (17 of 156) Bosniak category 2F cystic lesions progress to malignancy, and progression occurs within 6 months to 3.2 years.

Common postoperative findings unique to laparoscopic surgery.

The interpretation of images obtained in patients who have recently undergone abdominal or pelvic surgery is challenging, in part because procedures that were previously performed with open surgical techniques are increasingly being performed with minimally invasive (laparoscopic) techniques. Thus, it is important to be familiar with the normal approach used for laparoscopic surgeries. The authors describe the indications for various laparoscopic surgical procedures (eg, cholecystectomy, appendectomy, hernia repair) as well as normal postoperative findings. For example, port site hernias are more commonly encountered in patients with trocar sites greater than 10 mm and occur at classic entry sites (eg, the periumbilical region). Similarly, preperitoneal air can be encountered postoperatively, often secondary to trocar dislodgement during difficult entry or positioning. In addition, intraperitoneal placement of mesh during commonly performed ventral or incisional hernia repairs typically leads to postoperative seroma formation. Familiarity with normal findings after commonly performed laparoscopic surgical procedures in the abdomen and pelvis allows accurate diagnosis of common complications and avoidance of diagnostic pitfalls.

O-RADS MRI risk stratification system: pearls and pitfalls.

In 2021, the American College of Radiology (ACR) Ovarian-Adnexal Reporting and Data System (O-RADS) MRI Committee developed a risk stratification system and lexicon for assessing adnexal lesions using MRI. Like the BI-RADS classification, O-RADS MRI provides a standardized language for communication between radiologists and clinicians. It is essential for radiologists to be familiar with the O-RADS algorithmic approach to avoid misclassifications. Training, like that offered by International Ovarian Tumor Analysis (IOTA), is essential to ensure accurate and consistent application of the O-RADS MRI system. Tools such as the O-RADS MRI calculator aim to ensure an algorithmic approach. This review highlights the key teaching points, pearls, and pitfalls when using the O-RADS MRI risk stratification system.Critical relevance statement This article highlights the pearls and pitfalls of using the O-RADS MRI scoring system in clinical practice.Key points• Solid tissue is described as displaying post- contrast enhancement.• Endosalpingeal folds, fimbriated end of the tube, smooth wall, or septa are not solid tissue.• Low-risk TIC has no shoulder or plateau. An intermediate-risk TIC has a shoulder and plateau, though the shoulder is less steep compared to outer myometrium.

ACR Appropriateness Criteria® Pretreatment Evaluation and Follow-Up of Invasive Cancer of the Cervix: 2023 Update.

Cervical cancer is a common gynecological malignancy worldwide. Cervical cancer is staged based on the International Federation of Gynecology and Obstetrics (FIGO) classification system, which was revised in 2018 to incorporate radiologic and pathologic data. Imaging plays an important role in pretreatment assessment including initial staging and treatment response assessment of cervical cancer. Accurate determination of tumor size, local extension, and nodal and distant metastases is important for treatment selection and for prognostication. Although local recurrence can be diagnosed by physical examination, imaging plays a critical role in detection and follow-up of local and distant recurrence and subsequent treatment selection. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Multilocular cystic renal cell carcinoma: comparison of imaging and pathologic findings.

OBJECTIVE: The purpose of this study was to retrospectively correlate the imaging and pathologic features of multilocular cystic renal cell carcinoma (RCC), a low-grade neoplasm that has an excellent prognosis. MATERIALS AND METHODS: Institutional databases were searched for the period between 2001 and 2010 to identify cases of resected renal tumors that had been evaluated with CT or MRI and been analyzed by a uropathologist to confirm the histologic diagnosis of multilocular cystic RCC. The images (nine CT, 14 MRI) were reviewed, and a Bosniak cyst category was assigned. RESULTS: Of 23 confirmed cases of multilocular cystic RCC, imaging revealed seven lesions were Bosniak category IIF, 13 were category III, and three were category IV. Pathologic examination of the category IIF lesions revealed 99% fluid, 0.001-1% clear cells lining the septum, and 0% fibrosis. The category III lesions were 98-99% fluid, 1-2% clear cells, and 0% fibrosis. The category IV lesions were 20-40% fluid, 1-5% clear cells, and 60-80% fibrosis. The patient demographics were similar across groups. Clinical follow-up showed no evidence of recurrent or metastatic disease. CONCLUSION: Multilocular cystic RCC is a rare cystic lesion of the kidney that is low risk to the patient and benign in behavior. It has a variable imaging pattern, the Bosniak category ranging from IIF to IV. As multilocular cystic RCC lesions increase in complexity on images (higher Bosniak category), there is a corresponding increase in the volume of malignant cells lining the tumor and an increase in the presence of vascularized fibrous tissue. Regardless of the imaging appearance, the behavior of these tumors was benign in this study. Clinicians and radiologists should be aware that when this carcinoma is reported to occur, the patient has an excellent prognosis.

Current State of Membership Diversity Among North American Radiology Societies: Analysis of Public Information on Society Websites.

RATIONALE AND OBJECTIVES: Diversity is an identified priority amongst governing medical bodies. We systematically analyzed public membership diversity data posted by North American radiology societies. MATERIALS AND METHODS: Two independent study members reviewed North American radiology society websites to collect public data on membership diversity, specifically related to gender, race, and sexual orientation or gender identity, and categorized data using a coding system. Supplemental searches were conducted to confirm findings. Study team members created accounts on each society website to identify whether diversity data was collected during member enrollment. RESULTS: We reviewed a total of 26 society websites, with median 1500 members (range 110-54,600). We categorized five societies as "diversity leaders" based on having diversity statement(s), diversity initiatives, and diversity publication(s). While 62%, 8%, and 0% of societies collected data on gender, race, and sexual orientation or gender identity, respectively, no societies posted membership composition of these groups. Fourty-six percent of societies had membership diversity statement(s) on their webpages. Fifty-four percent had initiative(s) targeted at diversity (23% had multiple). Fifty percent had membership diversity publication(s). Sexual orientation and gender identity minority members were least frequently specified as beneficiaries of diversity statements, initiatives, and publications. Societies with larger memberships were more likely to have membership diversity initiatives (p = 0.01), journal articles on membership diversity (p = 0.005), and be "diversity leaders" (p = 0.02). CONCLUSION: Public support of membership diversity by many North American radiology societies, especially those with fewer members, is lacking. Identified "diversity leaders" can serve as models for societies aiming to establish their commitment to diversity.

ACR Appropriateness Criteria® Staging and Follow-up of Primary Vaginal Cancer.

Primary vaginal cancer is rare, comprising 1% to 2% of gynecologic malignancies and 20% of all malignancies involving the vagina. More frequently, the vagina is involved secondarily by direct invasion from malignancies originating in adjacent organs or by metastases from other pelvic or extrapelvic primary malignancies. Data on the use of imaging in vaginal cancer are sparse. Insights are derived from the study of imaging in cervical cancer and have reasonable generalizability to vaginal cancer due to similar tumor biology. Given the trend toward definitive chemoradiation for both cancers in all but early stage lesions, principles of postchemoradiation tumor response evaluation are largely analogous. Accordingly, many of the recommendations outlined here are informed by principles translated from the literature on cervical cancer. For pretreatment assessment of local tumor burden and in the case of recurrent vaginal cancer, MRI is the preferred imaging modality. PET/CT has demonstrated utility for the detection of nodal metastatic and unexpected distant metastatic disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Small (< 4 cm) Bosniak renal cysts: association of initial fluid percentage and enhancing solid volume thresholds with future lesion behavior.

PURPOSE: Evaluate the fluid percentage (FP) and enhancing solid volume (SV) of small (< 4 cm) Bosniak 2F, 3 and 4 renal lesions and the association with Bosniak category at baseline and follow-up. METHODS: Hospital database was searched from 1/1/2010 to 8/3/2018 for small (< 4 cm) Bosniak 2F, 3 and 4 lesions studied with initial and follow-up C+CT/MRI. Two radiologists blindly assigned Bosniak categories to first and last available studies. One radiologist performed volumetric analysis of each lesion, calculating the FP and SV. Association with Bosniak category was explored. RESULTS: 121 patients (84:37 M:F) were identified with 136 renal lesions (84, 37 and 15 Bosniak category 2F, 3 and 4) and followed for 1-12.3 years (mean 3.5 years). 87% (73/84) of 2F lesions were downgraded or remained stable. 48% (25/52) of 3/4 lesions were downgraded. Higher FP was associated with a lower Bosniak category (p value = 0.0042). Increase in FP was associated with the probability of being downgraded on follow-up (OR 1.03, p value = 0.0036), while increase in fluid volume of lesion was directly associated with change in overall lesion size among lesions that were downgraded (b-estimate = 0.03, p value = 0.0003). All Bosniak 3/4 lesions with initial SV less than 0.05 cc were downgraded. CONCLUSION: FP and SV are useful quantitative surrogates for Bosniak category and future behavior, respectively. Growth of small renal lesions by an increase in fluid volume and FP leads to a downgrade in Bosniak category. Initial SV less than 0.05 cc in Bosniak 3/4 lesions suggests possible future downgrade.

ACR Appropriateness Criteria® Liver Lesion-Initial Characterization.

Incidental liver masses are commonly identified on imaging performed for other indications. Since the prevalence of benign focal liver lesions in adults is high, even in patients with primary malignancy, accurate characterization of incidentally detected lesions is of paramount clinical importance. This document reviews utilization of various imaging modalities for characterization of incidentally detected liver lesions, discussed in the context of several clinical scenarios. For each clinical scenario, a summary of current evidence supporting the use of a given diagnostic modality is reported. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.