Artificial Intelligence for Quantifying Cumulative Small Bowel Disease Severity on CT-Enterography in Crohn's Disease.

INTRODUCTION: Assessing the cumulative degree of bowel injury in ileal Crohn's disease (CD) is difficult. We aimed to develop machine learning (ML) methodologies for automated estimation of cumulative ileal injury on computed tomography-enterography (CTE) to help predict future bowel surgery. METHODS: Adults with ileal CD using biologic therapy at a tertiary care center underwent ML analysis of CTE scans. Two fellowship-trained radiologists graded bowel injury severity at granular spatial increments along the ileum (1 cm), called mini-segments. ML segmentation methods were trained on radiologist grading with predicted severity and then spatially mapped to the ileum. Cumulative injury was calculated as the sum (S-CIDSS) and mean of severity grades along the ileum. Multivariate models of future small bowel resection were compared with cumulative ileum injury metrics and traditional bowel measures, adjusting for laboratory values, medications, and prior surgery at the time of CTE. RESULTS: In 229 CTE scans, 8,424 mini-segments underwent analysis. Agreement between ML and radiologists injury grading was strong (κ = 0.80, 95% confidence interval 0.79-0.81) and similar to inter-radiologist agreement (κ = 0.87, 95% confidence interval 0.85-0.88). S-CIDSS (46.6 vs 30.4, P = 0.0007) and mean cumulative injury grade scores (1.80 vs 1.42, P < 0.0001) were greater in CD biologic users that went to future surgery. Models using cumulative spatial metrics (area under the curve = 0.76) outperformed models using conventional bowel measures, laboratory values, and medical history (area under the curve = 0.62) for predicting future surgery in biologic users. DISCUSSION: Automated cumulative ileal injury scores show promise for improving prediction of outcomes in small bowel CD. Beyond replicating expert judgment, spatial enterography analysis can augment the personalization of bowel assessment in CD.

MRI assessment of rectal cancer response to neoadjuvant therapy: a multireader study.

OBJECTIVES: A watch and wait strategy with the goal of organ preservation is an emerging treatment paradigm for rectal cancer following neoadjuvant treatment. However, the selection of appropriate patients remains a challenge. Most previous efforts to measure the accuracy of MRI in assessing rectal cancer response used a small number of radiologists and did not report variability among them. METHODS: Twelve radiologists from 8 institutions assessed baseline and restaging MRI scans of 39 patients. The participating radiologists were asked to assess MRI features and to categorize the overall response as complete or incomplete. The reference standard was pathological complete response or a sustained clinical response for > 2 years. RESULTS: We measured the accuracy and described the interobserver variability of interpretation of rectal cancer response between radiologists at different medical centers. Overall accuracy was 64%, with a sensitivity of 65% for detecting complete response and specificity of 63% for detecting residual tumor. Interpretation of the overall response was more accurate than the interpretation of any individual feature. Variability of interpretation was dependent on the patient and imaging feature investigated. In general, variability and accuracy were inversely correlated. CONCLUSIONS: MRI-based evaluation of response at restaging is insufficiently accurate and has substantial variability of interpretation. Although some patients' response to neoadjuvant treatment on MRI may be easily recognizable, as seen by high accuracy and low variability, that is not the case for most patients. KEY POINTS: • The overall accuracy of MRI-based response assessment is low and radiologists differed in their interpretation of key imaging features. • Some patients' scans were interpreted with high accuracy and low variability, suggesting that these patients' pattern of response is easier to interpret. • The most accurate assessments were those of the overall response, which took into consideration both T2W and DWI sequences and the assessment of both the primary tumor and the lymph nodes.

Imaging Care for Transgender and Gender Diverse Patients: Best Practices and Recommendations.

Transgender and gender diverse (TGD) people experience health disparities, and many avoid necessary medical care because of fears of discrimination or mistreatment. Disparate care is further compounded by limited understanding of gender-affirming hormone therapy (GAHT) and gender-affirming surgery among the medical community. Specific to radiology, TGD patients report more negative imaging experiences than negative general health encounters, highlighting the need for guidance and best practices for inclusive imaging care. A patient's imaging journey provides numerous opportunities for improvement. Inclusive practice in a radiology department starts with ordering and scheduling the examination, facilitated by staff education on appropriate use of a patient's chosen name, gender identity, and pronouns. Contemporary electronic health record systems have the capacity for recording detailed sexual orientation and gender identity data, but staff must be trained to solicit and use this information. A welcoming environment can help TGD patients to feel safe during the imaging experience and may include institutional nondiscrimination policies, gender-neutral signage, and all-gender single-user dressing rooms and bathrooms. Image acquisition should be performed using trauma-informed and patient-centered care. Finally, radiologists should be aware of reporting considerations for TGD patients, such as avoiding the use of gender in reports when it is not medically relevant and using precise, respectful language for findings related to GAHT and gender-affirming surgical procedures. As a field, radiology has a range of opportunities for improving care delivery for TGD patients, and the authors summarize recommended best practices. See the invited commentary by Stowell in this issue. © RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Ultrasound (US) LI-RADS: Outcomes of Category US-3 Observations.

OBJECTIVE. The purpose of the study is to evaluate the outcomes of ultrasound (US) LI-RADS category US-3 observations detected at US performed for hepatocellular carcinoma (HCC) screening and surveillance on the basis of subsequently performed multi-phase MRI or CT or histopathology. MATERIALS AND METHODS. In this retrospective analysis, 267 patients at high risk for HCC (161 men and 106 women; mean [± SD] age, 58.6 ± 12.2 years) underwent screening liver US between January 2017 and June 2019 and were assigned US-3 observations on a prospective clinical basis using the US LI-RADS algorithm. The results of follow-up imaging studies and/or histopathology were analyzed. RESULTS. Visualization scores assigned at US were A (40.8% [109/267]), B (52.8% [141/267]), and C (6.4% [17/267]). Reasons for US-3 observations included a measurable mass of 1 cm or larger (88.8% [237/267]; mean size, 1.8 ± 1.0 cm; range, 1.0-6.9 cm), an area of parenchymal distortion of 1 cm or greater (7.9% [21/267]; mean size, 1.8 ± 0.9 cm; range, 1.0-4.0 cm), or a new venous thrombus (3.4% [9/267]). Confirmatory testing with multiphase contrast-enhanced MRI or CT or with histopathology was available for 81.6% (218/267) of patients. Causes of US-3 observations included no abnormality at MRI or CT (41.3% [90/218]), a benign lesion (32.6% [71/218]), a LI-RADS category 3 (LR-3) observation at MRI or CT (5.5% [12/218]), a LI-RADS category 4 or 5 (LR-4 or LR-5) observation at MRI or CT or identification of HCC at histopathology (18.8% [41/218]), and an LR-M (denoting probably or definitely malignant but without specific features for HCC) observation at MRI or CT or other malignancy at histopathology (1.8% [4/218]). The PPV of a US-3 observation for probable or definite HCC was 18.8%, and for any malignancy it was 20.6%. CONCLUSION. In the HCC screening population, approximately one in five US-3 observations represents probable or definite HCC at multiphase MRI or CT or HCC at histopathology. These findings support current US LI-RADS guidelines to pursue further evaluation with multiphase cross-sectional imaging for US-3 observations.

Comparison of International Ovarian Tumor Analysis Simple Rules to Society of Radiologists in Ultrasound Guidelines for Detection of Malignancy in Adnexal Cysts.

OBJECTIVE. The purpose of this study was to evaluate the International Ovarian Tumor Analysis (IOTA) simple rules and the Society of Radiologists in Ultrasound (SRU) guidelines for detecting ovarian malignancy in a general population of women presenting to radiology departments with adnexal cystic lesions. MATERIALS AND METHODS. A retrospective multicenter study of ultrasound-detected adnexal cystic lesions with appropriate follow-up was conducted. Lesions were classified into benign, indeterminate, or malignant categories according to criteria based on the IOTA simple rules and the SRU guidelines. The prevalence of nonneoplastic cysts, neoplasms, and malignant tumors was calculated. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated, and ROC analysis for the diagnosis of malignancy was performed. RESULTS. A total of 697 women with 764 cystic lesions were included; 85.2% (651/764) of the lesions were nonneoplastic, 12.2% (93/764) were benign neoplasms, and 2.6% (20/764) were malignant neoplasms. Nearly all malignancies were classified into indeterminate and malignant categories. The prevalence of malignancy in the indeterminate category was 4.8% (7/145) (SRU) to 10.7% (7/65) (IOTA) and in the malignant category was 18.1% (13/72) (SRU) to 34.3% (12/35) (IOTA). Only one malignancy was misclassified as benign by the IOTA simple rules. The sensitivity of the IOTA simple rules for malignancy was 90.0%; specificity, 96.5%; PPV, 29.0%; NPV, 99.8%; and accuracy, 96.4%. The corresponding values for the SRU guidelines were 100%, 89.6%, 14.9%, 100%, and 89.8%. In ROC analysis, the IOTA simple rules were slightly more accurate than the SRU guidelines (AUC, 0.9805 versus 0.9713; p = 0.0003). CONCLUSION. Both imaging characterization methods were sensitive for identifying ovarian malignancies, but the PPV was low among women presenting to radiology departments, and the indeterminate classification harbored one-third of the total malignancies. Exploration of varied clinical settings and inclusion of secondary tests may help to refine these systems.

Retrospective Cohort Study of 1947 Thyroid Nodules: A Comparison of the 2017 American College of Radiology TI-RADS and the 2015 American Thyroid Association Classifications.

OBJECTIVE. The objective of our study was to compare diagnostic accuracy and reliability of the 2017 American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) and 2015 American Thyroid Association (ATA) classifications for thyroid nodules. MATERIALS AND METHODS. This study was a retrospective cohort study of 1947 consecutive thyroid nodules sampled with fine-needle aspiration (FNA) from 2007 to 2016. Reviewers assigned TI-RADS scores to all nodules while blinded to clinical outcome and histologic diagnosis and compared TI-RADS scores with nodule-specific ATA scores from the same cohort. Five blinded radiologists independently assigned TI-RADS scores to a subset of 151 nodules (interrater agreement). The primary outcome was a comparison of the diagnostic accuracy of the TI-RADS and ATA classifications using ROC curve analysis. The reference standard was cytopathologic diagnosis according to the Bethesda system. Interrater agreement was determined using intraclass correlation (ICC) and kappa statistics. RESULTS. Of 1947 sampled thyroid nodules, 31.8% (n = 620) met TI-RADS criteria for FNA, 28.0% (n = 545) met TI-RADS criteria for follow-up, and 40.2% (n = 782) met TIRADS criteria to be ignored. Applying the 2015 ATA criteria resulted in recommendations of immediate FNA procedures for more nodules than applying the 2017 TI-RADS (ATA vs TIRADS: 62.3% [1213/1947] vs 31.8% [620/1947], p < 0.0001). Diagnostic accuracies (AUCs: TI-RADS score, 0.684 [95% CI, 0.644-0.724]; ATA, 0.686 [95% CI, 0.646-0.725]) and false-negative rates (TI-RADS, 2.2% [43/1947]; ATA, 2.4% [47/1947]) for the two classifications were similar (p = 0.75). Overall interrater agreement was fair for both (ICCs: TI-RADS, 0.437 [95% CI, 0.357-0.520]; ATA classification, 0.460 [95% CI, 0.391-0.533]). CONCLUSION. The 2017 ACR TI-RADS and 2015 ATA classifications have similar diagnostic accuracies and interrater agreement, but TI-RADS results in fewer nodules being recommended for immediate FNAs and more nodules being recommended for imaging surveillance.

Role of US LI-RADS in the LI-RADS Algorithm.

The US Liver Imaging Reporting and Data System (LI-RADS) was released in 2017 and is the newest of the four American College of Radiology (ACR) LI-RADS algorithms. US LI-RADS provides standardized terminology, technical recommendations, and a reporting framework for US examinations performed for screening or surveillance in patients at risk for developing hepatocellular carcinoma (HCC). The appropriate patient population for screening and surveillance includes individuals who are at risk for developing HCC but do not have known or suspected cancer. This includes patients with cirrhosis from any cause and subsets of patients with chronic hepatitis B virus infection in the absence of cirrhosis. In an HCC screening or surveillance study, US LI-RADS recommends assigning two scores that apply to the entire study: the US category, which determines follow-up, and a visualization score, which communicates the expected level of sensitivity of the examination but does not affect management. Three US categories are possible: US-1 negative, a study with no evidence of HCC; US-2 subthreshold, a study in which an observation less than 10 mm is depicted that is not definitely benign; and US-3 positive, a study in which an observation greater than or equal to 10 mm or a new thrombus in vein is identified, for which diagnostic contrast material-enhanced imaging is recommended. Three visualization scores are possible: A (no or minimal limitations), B (moderate limitations), and C (severe limitations). ©RSNA, 2019.

Transvaginal Ultrasound Shear Wave Elastography for the Evaluation of Benign Uterine Pathologies: A Prospective Pilot Study.

OBJECTIVES: This study evaluated the diagnostic performance of transvaginal ultrasound (TVUS) shear wave elastography (SWE) for evaluating uterine adenomyosis and leiomyomas. METHODS: Institutional Review Board approval was obtained for prospective enrollment of 34 premenopausal women with pelvic pain and/or bleeding between January 2015 and June 2016. TVUS SWE was performed with regions of interest in multiple uterine segments and shear wave velocities(SWVs) were recorded. Reference pelvic magnetic resonance examinations were performed and reviewed without access to the ultrasound results. RESULTS: Continuous variables were analyzed using means, t tests, and analysis of variance. Magnetic resonance imaging revealed adenomyosis in 6 women (12 uterine segments) and leiomyomas in 12 women (28 segments). On a per-patient basis, mean SWV in 16 women with no adenomyosis or leiomyoma was 4.3 ± 1.7 m/s, compared with 5.7 ± 2.3 m/s in 18 women with a magnetic resonance diagnosis of myometrial pathology (P < .0002; 95% confidence interval, -2.2, -0.6). On a per-segment basis, SWV in normal myometrium was 4.8 ± 1.9 m/s, compared with 4.9 ± 2.5 m/s in adenomyosis and 5.6 ± 2.5 m/s in leiomyoma (P = .34 by one-way analysis of variance). In pairwise comparison, SWV for adenomyosis and leiomyoma did not differ significantly (P = .40). CONCLUSIONS: TVUS SWE did not distinguish adenomyosis from leiomyoma. However, our pilot study demonstrated that myometrial SWVs were higher in uteri with adenomyosis and leiomyomas than in uteri with myometrium with no abnormalities suggesting a potential role for SWE in treatment response assessment.

Quantitative Assessment of Liver Stiffness Using Ultrasound Shear Wave Elastography in Patients With Chronic Graft-Versus-Host Disease After Allogeneic Hematopoietic Stem Cell Transplantation: A Pilot Study.

OBJECTIVES: The purpose of this study was to compare hepatic stiffness on ultrasound (US) shear wave elastography (SWE) in patients with chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation versus patients with no underlying liver disease. METHODS: We performed a retrospective analysis of 4901 patients who underwent abdominal US examinations with adjunctive liver SWE between August 2014 and December 2016. Each patient was scanned supine with gentle breath holding on LOGIQ E9 (GE Healthcare, Waukesha, WI) or Epiq (Philips Healthcare, Andover, MA) US machines (3-6 MHz). Three to 10 measurements were made intercostally in the right hepatic lobe, following manufacturers' guidelines before release of the 2015 Society of Radiologists in Ultrasound consensus or the 2015 Society of Radiologists in Ultrasound consensus. The median and standard deviation of the shear wave velocity (SWV) were obtained. A 2-sample t test with the Welch approximation was used for statistical analysis. RESULTS: Six patients had documented hepatic chronic GVHD or a high clinical suspicion of liver chronic GVHD. All had normal pretransplant liver function test results and no pretransplant or posttransplant hepatic infection. The control group, obtained from the same database, contained 10 patients with normal liver function test results, no abdominal pain, and no history of liver disease or conditions that may have caused liver stiffness changes. The SWVs in patients with chronic GVHD were double those in the control group (1.96 ± 0.28 versus 0.98 ± 0.27 m/s; P < .0001). CONCLUSIONS: Patients with chronic GVHD had substantially higher hepatic parenchymal SWVs than patients without liver disease, indicating increased tissue stiffness. To our knowledge, this phenomenon has not been previously reported in chronic GVHD and suggests potential utility of SWE for diagnosis and monitoring of disease progression and the treatment response in this cohort of patients.

Indeterminate Adnexal Cysts at US: Prevalence and Characteristics of Ovarian Cancer.

Purpose To assess the prevalence of indeterminate adnexal cysts in women presenting to academic medical centers for pelvic ultrasonography (US), determine the incidence of malignancy, and identify cyst and patient characteristics that are predictive of malignancy. Materials and Methods A multicenter study of US-detected adnexal cysts with appropriate follow-up (surgical pathologic examination, imaging and/or clinical examination) was conducted from January 2008 to June 2012. Indeterminate cysts were classified as category 1 (typical benign appearing cysts >5 cm) or category 2 (cysts with avascular solid components) on the basis of a combination of definitions in the existing literature. The incidence of neoplasms and malignant tumors was calculated. Patient and cyst characteristics associated with neoplasm and malignant tumors were evaluated with the χ2 test or Fisher exact test for categorical variables and the t test for continuous variables. A backward stepwise logistic regression model was performed for two outcomes: (a) the presence of any neoplasm (benign or malignant) and (b) the presence of a malignant tumor. Results There were 1637 women with an adnexal cyst at US; 391 (mean age = 41.8 years ± 13.5.1; range = 17-91 years) had an indeterminate adnexal cyst at US. The prevalence of indeterminate adnexal cysts was 23.9% (391 of 1637; 95% confidence interval [CI]: 0.22, 0.26). Three hundred three indeterminate cysts in 280 women (mean age = 42.9 years ± 14.1; range = 17-88 years) had adequate follow-up. The incidence of ovarian neoplasms (benign and malignant) was 24.8% (75 of 303 cysts; 95% CI: 0.20, 0.30), and the incidence of malignant tumors was 3.6% (11 of 303 cysts; 95% CI: 0.02, 0.06). The proportion of ovarian neoplasms differed between category 1 and category 2 cysts (17.5% [25 of 143 cysts; 95% CI: 0.12, 0.25] vs 31.3% [50 of 160 cysts; 95% CI: 0.24, 0.39], respectively; P = .001). The proportion of malignant tumors differed between categories 1 and 2 cysts (0% [0 of 143 cysts] vs 6.9% [11 of 160 cysts; 95% CI: 0.03, 0.12]; P < .001). The presence of an avascular nodular component was a significant predictor of malignancy at stepwise logistic regression analysis (odds ratio = 2.83; P ≤ .0001; 95% CI: 1.69, 4.70). Conclusion The presence of an avascular nodular component was the most significant predictor of the presence of malignancy in indeterminate adnexal cysts. The risk of malignancy is higher with category 2 cysts than with category 1 cysts. © RSNA, 2018.

Risk Stratification of Adnexal Cysts and Cystic Masses: Clinical Performance of Society of Radiologists in Ultrasound Guidelines.

Purpose To evaluate the performance of the 2010 Society of Radiologists in Ultrasound (SRU) consensus guidelines in the risk stratification of symptomatic and asymptomatic adnexal cysts. Materials and Methods An institutional review board-approved retrospective review was performed, including adnexal cysts detected with ultrasonography (US) with surgical diagnosis or at least 2 years of imaging or clinical follow-up, from January to June 2011. SRU management recommendations were scored as 0, no follow-up; 1, US follow-up; 2, magnetic resonance (MR) imaging follow-up; and 3, surgical evaluation. Distribution of outcomes (nonneoplastic cyst, benign neoplasm, malignant neoplasm) was compared in each rating group by using the Cochran-Armitage trend test. Where SRU guidelines allow more than one management option, they were classified as being interpreted in either a "surgically focused" environment, with limited MR imaging availability, or an "MR-capable" center, where MR imaging is selected whenever it is an option. Predictors of neoplasms and malignancy were evaluated by using multivariate logistic regression. Results A total of 570 cysts in 500 women aged 18-90 years (mean, 42 years) were included. There were 475 (83.3%) nonneoplastic cysts, 77 (13.5%) benign neoplasms, and 18 (3.2%) malignant neoplasms. Of the 500 women, 161 (32.2%) were asymptomatic. In the surgically focused interpretation of guidelines, proportions of any neoplasm and malignant neoplasm, respectively, were 1% and 0% in SRU 0, 17% and 1% in SRU 1, 48% and 0% in SRU 2, and 48% and 16% in SRU 3 (P < .0001 for both trends). In the interpretation of SRU guidelines with MR imaging when it was an option, proportions of any neoplasm and malignant neoplasm, respectively, were 1% and 0% in SRU 0, 17% and 1% in SRU 1, 38% and 5% in SRU 2, and 81% and 52% in SRU 3 (P < .0001, both trends) and 82 (89.1%) fewer benign cysts would have gone directly to surgical evaluation. In multivariate regression, SRU rating predicted both any neoplasm (odds ratio, 2.58; P < .0001) and malignant neoplasm (odds ratio, 4.94; P = .005). Conclusion SRU consensus guidelines effectively stratified the risk of neoplasia and malignancy. Selecting MR imaging when it is an option in the guidelines would have reduced the number of benign cysts sent for surgical evaluation. © RSNA, 2017.

Sonographic diagnosis of partial versus complete molar pregnancy: A reappraisal.

PURPOSE: To assess the prospective sonographic diagnosis of molar pregnancy and compare sonographic features of complete versus partial molar pregnancy. METHODS: This institutional review board--approved retrospective chart review conducted between 2001 and 2011 identified 70 women with a histopathologic diagnosis of molar pregnancy and with available sonograms. Clinical data, images, and reports were reviewed, and features enumerated by radiologists blinded to the final diagnosis. RESULTS: Mean age of patients was 30.5 ± 7.0 (SD) years (range, 16-49 years) with a mean gravidity of 3.2 ± 2.3 (SD) (range 1-11). Mean gestational age was 74.0 ± 19.1 day (range 39-138) and serum ß-human chorionic gonadotropin was 131 ± 156 mIU/ml (range 447-662,000). Pathologic results showed 48 partial and 22 complete molar pregnancies. Sonographically, partial moles more commonly showed a yolk sac (56.3% versus 0%, p < 0.0001), fetal pole (62.5% versus 4.6%, p < 0.0001), fine septa within the sac (25.0% versus 4.6%, p = 0.05), and normal (31.3% versus 0%, p = 0.002) or minimally cystic placenta (27.1% versus 4.6%, p = 0.49), while complete moles had larger gestational sacs (612 versus 44 mm, p = 0.005), were more often avascular on color Doppler imaging (45.5% versus 18.8%, p = 0.02), had more often abnormal tissue in the uterus (82.6% versus 20.8%, p < 0.0001) and placental masses (86.9% versus 16.7%, p < 0.0001), and were more often diagnosed prospectively (86.4% versus 41.7%, p = 0.0005). CONCLUSIONS: Complete molar pregnancy is associated with marked cystic changes and mass formation and is often diagnosed sonographically. Partial molar pregnancy often presents with minor cystic changes of the placenta and remains underdiagnosed sonographically. However, correct prospective diagnosis was made more frequently in this study than in older reports, perhaps due to improved spatial resolution of sonographic equipment. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:72-78, 2017.

Primary and secondary disease of the peritoneum and mesentery: review of anatomy and imaging features.

The largest and most complex serosal membrane in the body, the peritoneum, lines the abdominal cavity, and the abdominopelvic viscera. It is frequently involved in a variety of benign and malignant processes. While secondary involvement of the peritoneum is more common, primary tumors can be a diagnostic challenge. Knowledge of the anatomy is crucial in understanding the various pathologic processes. Cross-sectional imaging plays an important role in diagnosing and evaluating the extent of the disease processes. This article reviews the imaging anatomy of the peritoneum and mesentery and the common pathologies involving it.

MDCT findings in small bowel obstruction: implications of the cause and presence of complications on treatment decisions.

Small bowel obstruction (SBO) accounts for a considerable proportion of emergency room visits, inpatient admissions, and surgical interventions in the United States. Multi-detector computed tomography (MDCT) plays a key role in imaging patients presenting with acute symptoms suggestive of SBO, which helps in establishing the diagnosis, elucidating the cause of obstruction, and detecting complications, such as ischemia or frank bowel necrosis and perforation. Recently, management of patients with SBO has shifted toward a more conservative approach with supportive care and nasogastric tube decompression, as the obstruction in many cases can resolve spontaneously without the need for operative intervention. However, management decisions in SBO remain notoriously difficult, relying on a combination of clinical, laboratory, and imaging factors to help stratify patients into conservative or surgical treatment. Imaging is often an important factor assisting in the decision-making process since traditional clinical signs of vascular compromise, such as acidosis, fever, leukocytosis, and tachycardia are often unreliable in predicting the need for operative intervention. Thus, it is critically important for radiologists to identify imaging features that suggest or indicated high likelihood of bowel vascular compromise in order to help optimize management prior to the development of bowel ischemia and eventually necrosis. By excluding signs of potentially ischemic or necrotic bowel on MDCT, patients may be spared unnecessary surgery, thus decreasing postsurgical complications and averting potential increase for the risk of future SBO and repeated surgery. Conversely, if imaging features indicate potential vascular compromise of the bowel wall that may lead to bowel ischemia, urgent surgical intervention may prevent progression to bowel necrosis and subsequent perforation.

Repeatability of diagnostic features and scoring systems for hepatocellular carcinoma by using MR imaging.

PURPOSE: To determine for expert and novice radiologists repeatability of major diagnostic features and scoring systems (ie, Liver Imaging Reporting and Data System [LI-RADS], Organ Procurement and Transplantation Network [OPTN], and American Association for the Study of Liver Diseases [AASLD]) for hepatocellular carcinoma (HCC) by using magnetic resonance (MR) imaging. MATERIALS AND METHODS: Institutional review board approval was obtained and patient consent was waived for this HIPAA-compliant, retrospective study. The LI-RADS discussed in this article refers to version 2013.1. Ten blinded readers reviewed 100 liver MR imaging studies that demonstrated observations preliminarily assigned LI-RADS scores of LR1-LR5. Diameter and major HCC features (arterial hyperenhancement, washout appearance, pseudocapsule) were recorded for each observation. LI-RADS, OPTN, and AASLD scores were assigned. Interreader agreement was assessed by using intraclass correlation coefficients and κ statistics. Scoring rates were compared by using McNemar test. RESULTS: Overall interreader agreement was substantial for arterial hyperenhancement (0.67 [95% confidence interval {CI}: 0.65, 0.69]), moderate for washout appearance (0.48 [95%CI: 0.46, 0.50]), moderate for pseudocapsule (0.52 [95% CI: 050, 0.54]), fair for LI-RADS (0.35 [95% CI: 0.34, 0.37]), fair for AASLD (0.39 [95% CI: 0.37, 0.42]), and moderate for OPTN (0.53 [95% CI: 0.51, 0.56]). Agreement for measured diameter was almost perfect (range, 0.95-0.97). There was substantial agreement for most scores consistent with HCC. Experts agreed significantly more than did novices and were significantly more likely than were novices to assign a diagnosis of HCC (P < .001). CONCLUSION: Two of three major features for HCC (washout appearance and pseudocapsule) have only moderate interreader agreement. Experts and novices who assigned scores consistent with HCC had substantial but not perfect agreement. Expert agreement is substantial for OPTN, but moderate for LI-RADS and AASLD. Novices were less consistent and less likely to diagnose HCC than were experts.

Emerging techniques for dose optimization in abdominal CT.

Recent advances in computed tomographic (CT) scanning technique such as automated tube current modulation (ATCM), optimized x-ray tube voltage, and better use of iterative image reconstruction have allowed maintenance of good CT image quality with reduced radiation dose. ATCM varies the tube current during scanning to account for differences in patient attenuation, ensuring a more homogeneous image quality, although selection of the appropriate image quality parameter is essential for achieving optimal dose reduction. Reducing the x-ray tube voltage is best suited for evaluating iodinated structures, since the effective energy of the x-ray beam will be closer to the k-edge of iodine, resulting in a higher attenuation for the iodine. The optimal kilovoltage for a CT study should be chosen on the basis of imaging task and patient habitus. The aim of iterative image reconstruction is to identify factors that contribute to noise on CT images with use of statistical models of noise (statistical iterative reconstruction) and selective removal of noise to improve image quality. The degree of noise suppression achieved with statistical iterative reconstruction can be customized to minimize the effect of altered image quality on CT images. Unlike with statistical iterative reconstruction, model-based iterative reconstruction algorithms model both the statistical noise and the physical acquisition process, allowing CT to be performed with further reduction in radiation dose without an increase in image noise or loss of spatial resolution. Understanding these recently developed scanning techniques is essential for optimization of imaging protocols designed to achieve the desired image quality with a reduced dose.

Radiologic-pathologic correlation in extra-adrenal myelolipoma.

Myelolipoma is an uncommon benign tumor that classically arises in the adrenal glands. Most cases are asymptomatic, with incidental detection of this tumor on cross-sectional imaging performed for other causes. Extra-adrenal occurrence of myelolipoma has been infrequently reported, with scarce radiology literature on the topic. We present radiologic and pathologic correlation in two cases of image-guided biopsy proven extra-adrenal myelolipoma in the presacral and paraaortic location, with review of literature.

Retroperitoneal lobular capillary hemangioma with synchronous ipsilateral renal cell carcinoma.

Lobular capillary hemangiomas (LCH) are acquired benign vascular tumors of skin and mucosal spaces of head and neck. Very few cases of LCH have been reported in the abdomen, predominantly occurring as mucosal polyps in the bowel. We present CT imaging features of solitary retroperitoneal LCH in a patient with synchronous ipsilateral renal cell carcinoma and review the available literature and imaging features in abdominal and extra-abdominal LCH. To our knowledge, there is no other case of retroperitoneal LCH available in the English literature.