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Objective: To assess the performance of morphologic and hypointense signal changes on MRI to predict grades and types of acetabular cartilage damage in the chondrolabral transitional zone (TZ) of the hip identified at arthroscopy. Materials and methods: This retrospective single-center study reviewed conventional 3T MRI hip studies from individuals with symptomatic femoroacetabular impingement (FAI) and subsequent hip arthroscopy surgery within 6 months. Independent review was made by three radiologists for the presence of morphologic damage or a hypointense signal lesion in the TZ on MRI. Fleiss' kappa statistic was used to assess inter-reader agreement. The degree of TZ surfacing damage (modified Outerbridge grades 1–4) and presence of non-surfacing wave sign at arthroscopic surgery were collected. Relationship between sensitivity and lesion grade was examined. Results: One hundred thirty-six MRI hip studies from 40 males and 74 females were included (mean age 28.5 years, age range 13–54 years). MRI morphologic lesions had a sensitivity of 64.9–71.6% and specificity of 48.4–67.7% for arthroscopic surfacing lesions, with greater sensitivity seen for higher grade lesions. Low sensitivity was seen for wave sign lesions (34.5–51.7%). MRI hypointense signal lesions had a sensitivity of 26.3–62% and specificity of 43.8–78.0% for any lesion. Inter-reader agreement was moderate for morphologic lesions (k = 0.601) and poor for hypointense signal lesions (k = 0.097). Conclusion: Morphologic cartilage damage in the TZ on MRI had moderate sensitivity for any cartilage lesion, better sensitivity for higher grade lesions, and poor sensitivity for wave sign lesions. The diagnostic value of hypointense signal lesions was uncertain. [ABSTRACT FROM AUTHOR]

Objectives: To compare the diagnostic accuracy of generalist radiologists working in a community setting against abdominal radiologists working in an academic setting for the interpretation of MR when diagnosing acute appendicitis among emergency department patients. Methods: This observational study examined MR image interpretation (non-contrast MR with diffusion-weighted imaging and intravenous contrast-enhanced MR) from a prospectively enrolled cohort at an academic hospital over 18 months. Eligible patients had an abdominopelvic CT ordered to evaluate for appendicitis and were > 11 years old. The reference standard was a combination of surgery and pathology results, phone follow-up, and chart review. Six radiologists blinded to clinical information, three each from community and academic practices, independently interpreted MR and CT images in random order. We calculated test characteristics for both individual and group (consensus) diagnostic accuracy then performed Chi-square tests to identify any differences between the subgroups. Results: Analysis included 198 patients (114 women) with a mean age of 31.6 years and an appendicitis prevalence of 32.3%. For generalist radiologists, the sensitivity and specificity (95% confidence interval) were 93.8% (84.6–98.0%) and 88.8% (82.2–93.2%) for MR and 96.9% (88.7–99.8%) and 91.8% (85.8–95.5%) for CT. For fellowship-trained radiologists, the sensitivity and specificity were 96.9% (88.2–99.5%) and 89.6% (82.8–94%) for MR and 98.4% (90.5–99.9%) and 93.3% (87.3–96.7%) for CT. No statistically significant differences were detected between radiologist groups (p = 1.0, p = 0.53, respectively) or when comparing MR to CT (p = 0.21, p = 0.17, respectively). Conclusions: MR is a reliable, radiation-free imaging alternative to CT for the evaluation of appendicitis in community-based generalist radiology practices. Key Points: • There was no significant difference in MR image interpretation accuracy between generalist and abdominal fellowship-trained radiologists when evaluating sensitivity (p = 1.0) and specificity (p = 0.53). • There was no significant difference in accuracy comparing MR to CT imaging for diagnosing appendicitis for either sensitivity (p = 0.21) or specificity (p = 0.17). • With experience, generalist radiologists enhanced their MR interpretation accuracy as demonstrated by improved interpretation sensitivity (OR 2.89 CI 1.44-5.77, p = 0.003) and decreased mean interpretation time (5 to 3.89 min). [ABSTRACT FROM AUTHOR]

Objectives: We sought to determine the diagnostic accuracy of magnetic resonance (MR) imaging compared with computed tomography (CT) and ultrasound (US) when evaluating for five common pelvic pathologies among women presenting to the emergency department (ED) with right lower quadrant abdominal pain. Methods: This prospective, single-center study was conducted at an academic ED as a sub-analysis of a direct comparison of the diagnostic accuracy of CT and MR in the evaluation of appendicitis. Patients were eligible for participation in the parent study if they were at least 12 years old and had a CT performed for evaluation of possible appendicitis. In the current study, only female patients who also underwent pelvic US were included. Three radiologists independently interpreted each MR examination specifically for the presence of pelvic pathology, knowing that patients had initially undergone imaging evaluation for possible appendicitis. The determination of an independent expert panel of two radiologists and one emergency physician based on surgical pathology, comprehensive chart review, clinical information, and follow-up phone calls served as the reference standard. Test characteristics of MR, CT, and US were calculated based on this; the main outcome measure was the summary sensitivity and specificity of MR versus CT and US. Results: Forty-one participants were included with a mean age of 27.6 ± 10.8 years. The MR consensus interpretation had an overall sensitivity and specificity of 57.1% (CI 38.8–75.5%) and 97.2% (CI 94.7–99.6%) respectively, for detecting any of the five pelvic pathologies. By comparison, CT exhibited sensitivity and specificity of 66.7% (CI 50.0–83.5%) and 98.3% (CI 96.4–100.0%) while it was 64.3% (CI 46.5–82.0%) and 97.7% (CI 95.6–99.9%) for US, respectively. No significant differences were identified when comparing these modalities. Overall, Fleiss' kappa interrater reliability value for MR interpretation was 0.75, corresponding to substantial agreement between the three readers. Conclusions: In women who might otherwise undergo multiple imaging tests to evaluate gastrointestinal versus pelvic pathologies, our data suggest that MR may be an acceptable first-line imaging test. [ABSTRACT FROM AUTHOR]

The following corrections have therefore been made in the original: The spelling of Newrhee Kim's name was incorrect and the middle name in Perry J. Pickhardt's name was missing. The original article can be found online at https://doi.org/10.1007/s00330-021-08163-7. [Extracted from the article]