Knee MRI Primary Care Ordering Practices for Nontraumatic Knee Pain: Compliance With ACR Appropriateness Criteria and Its Effect on Clinical Management.

PURPOSE: To evaluate the appropriateness of MRI ordering practices and their effect on clinical management for nontraumatic knee pain at the primary care clinics of a large public urban hospital. MATERIALS AND METHODS: In all, 196 consecutive MRIs for nontraumatic knee pain ordered from primary care clinics in a large public urban hospital over an 18-month period were studied. ACR Appropriateness Criteria (AC) scores for nontraumatic knee pain were retrospectively calculated from medical record reviews. The record was also reviewed to assess whether knee MRI changed clinical management. Knee osteoarthritis grading was performed. Tests were performed for differences in age, body mass index (BMI), gender, and ethnicity among appropriate and inappropriate MRIs. RESULTS: Of the MRIs, 57% (108 knees) had "usually appropriate" (ie, 7-9) and 43% (8 knees) had "usually not appropriate" (ie, 1-3) AC scores (P > .1). Clinical management was changed in 26% of knees with "usually appropriate" and 20% of knees with "usually inappropriate" scores (P < .05), and 70% of the knees with "usually appropriate" and 61% of the knee with "usually not appropriate" scores had moderate to severe osteoarthritis. Age, BMI, gender, and ethnicity had no significant effect on AC scores. CONCLUSION: In patients referred from primary care for MRI for nontraumatic knee pain, adherence to AC was low. Additional focus on reducing "appropriate" studies that do not impact clinical management (eg, cases with radiographically evident moderate to severe osteoarthritis) is also warranted.

Anatomic Relationship and Imaging Relevance of the Perforating Branches of the Peroneal Vessels to the Anterior Talofibular Ligament.

BACKGROUND: Patients frequently present to the emergency department after ankle injuries, and the anterior talofibular ligament (ATFL) is commonly damaged. Musculoskeletal ultrasound (US) can help to make a rapid diagnosis. There is a paucity of literature describing techniques to image the ATFL with US, and the complex ankle anatomy and potential pitfalls make imaging challenging. OBJECTIVE: Our aim was to estimate prevalence of perforating branches (PBs) of the peroneal vessels and determine their most frequent position relative to the ATFL. If these vessels are located in a predictable position at the level of the ATFL, they may serve as a sonographic landmark for the correct imaging plane. METHODS: Magnetic resonance imaging (MRI) scans of 105 ankles were reviewed to determine the PB prevalence and location at the ATFL. Inter-observer agreement was determined. Additionally, 16 ankles from 8 asymptomatic subjects were scanned using a high-frequency linear transducer and PB prevalence and location were noted. RESULTS: By MRI, PBs were detected in 85% of the ankles and 93% of ankles after consensus. In 73% of cases with agreed PB visualization, vessels assumed a medial position with respect to the ATFL. By US, PBs could be seen in 100% of cases, with the arterial PB seen in 81% of cases and assuming a medial position in 88%. CONCLUSIONS: PBs are often present, have a predictable course, and may be useful to help optimize US probe positioning when assessing the ATFL.

Altered Mental Status in ICU Patients: Diagnostic Yield of Noncontrast Head CT for Abnormal and Communicable Findings.

OBJECTIVE: To evaluate the diagnostic yield of noncontrast head CT for acute communicable findings in ICU patients specifically scanned for altered mental status. DESIGN: Retrospective observational cohort study. SETTING: University Hospital Neuroscience, Medical, and Surgical ICUs. PATIENTS: ICU patients with new-onset altered mental status. INTERVENTION: Noncontrast head CT. MEASUREMENTS AND MAIN RESULTS: Reports on head CTs from two university hospitals performed for the sole indication of altered mental status in ICU patients between July 2011 and June 2013 were reviewed for 1) acute (new or worsening) hemorrhage, 2) mass effect/herniation, 3) infarction, and 4) hydrocephalus. Subgroup analyses of positive findings were performed by 1) ICU group type, 2) age, and 3) race. A total of 2,486 head CTs were performed in 1,357 patients whose age ranged from 14 to 116 years (median, 59; mean, 57.6 ± 16). Acute communicable findings in at least one of four categories were present in 22.8% (566/2,486) of examinations, with hydrocephalus being most common (11.5% [286/2,486]). The frequency of any acute communicable findings in neuroscience, medical, and surgical ICUs was 28.6% (471/1,648), 9.8% (43/440), and 13.1% (52/398), respectively. Neuroscience ICU head CTs had significantly higher rates of acute communicable findings in all categories, except for acute infarction, compared with the other two ICUs (p < 0.001). Acute hydrocephalus (13.6% vs 7.4%; p < 0.001) and mass effect (6.7% vs 4.3%; p = 0.01) were more common in patients less than 65 years. For other acute categories, no significant difference was noted by age. There was no significant difference in the likelihood of a positive examination by race. CONCLUSIONS: Almost one in four head CTs in a university ICU patient population performed for primary indication of altered mental status yields abnormal communicable findings. In this patient population, utilization management barriers to examination ordering should be minimized.

Congenital absence of the semimembranosus muscle: case report.

Congenital anomalies of the muscles of the lower extremity are rare. A case of complete absence of the semimembranosus muscle incidentally found with magnetic resonance imaging is reported. The patient was a 55-year-old female presenting with knee pain and no previous history of trauma. Clinical and imaging findings were consistent with meniscal tears. Two cases of uncommon distal insertion of the semimembranosus tendon are also described to illustrate the anatomical variations in this area. The anatomical and biomechanical relations between the semimembranosus muscle and the posteromedial corner of the knee are examined in this case report.