Subtendinous bone marrow edema patterns on MR images of the ankle: association with symptoms and tendinopathy.

OBJECTIVE: We sought to describe a pattern of subtendinous bone marrow edema on MR images of the ankle and to determine if there is an association with location of symptoms and overlying tendinopathy. MATERIALS AND METHODS: At 1.5 T, 141 MR examinations of the ankle (116 clinical examinations of patients with chronic pain, 25 of asymptomatic control patients) were performed using T1-weighted, proton density-weighted fast spin-echo, and T2-weighted fat-suppressed fast spin-echo sequences. Images were retrospectively reviewed by two musculoskeletal radiologists for presence of bone marrow edema occurring in a subcortical location associated with the course of the medial or lateral tendon groups, as well as focal thickening or increased T2 signal within the tendons. These findings were correlated with clinical information regarding symptom location. The association of subtendinous marrow edema with tendinopathy and symptom location was statistically analyzed. RESULTS: Subtendinous bone marrow edema was present at 26 sites on 24 ankle MR examinations (17%) (at the medial malleolus [n = 17] associated with the posterior tibialis tendon, at the lateral malleolus [n = 6] and the calcaneus [n = 2] associated with the peroneus longus and brevis tendons, and at the cuboid [n = 1] associated with the peroneus longus tendon). These subtendinous bone marrow edema patterns were significantly associated with overlying tendon abnormality medially (p = 0.001) and laterally (p = 0.001), and with symptoms medially (p = 0.0016) but not laterally (p = 0.078). CONCLUSION: On MR images of the ankle, bone marrow edema localized in a subtendinous location is associated with overlying tendinopathy medially and laterally and with ankle pain medially.

Pearls and pitfalls in the diagnosis of ureterolithiasis with unenhanced helical CT.

Several signs to assist interpretation of unenhanced helical computed tomographic (CT) scans obtained for suspected ureterolithiasis have been described. Because signs such as perinephric stranding are not always readily apparent, a methodical approach to interpretation of CT studies is important in determining the presence or absence of ureterolithiasis. Evaluation of the poles of the kidneys is helpful in detecting subtle stranding of the perinephric fat. Inspection of the intrarenal collecting system within the poles of the kidneys is helpful in identifying subtle collecting system dilatation and can help prevent mistaking an extrarenal pelvis for hydronephrosis. Careful inspection of the ureter throughout its course is the most reliable method of distinguishing between ureteral stones and phleboliths. However, when the ureter cannot be followed antegrade, the pelvic portion can often be identified in a retrograde fashion. When secondary signs of obstruction are present but no stone is present, differential diagnostic considerations include a recently passed stone, pyelonephritis, urinary tract obstruction unrelated to stone disease, and protease inhibitor deposition disease.

Single institution prospective evaluation of the over-the-wire Greenfield vena caval filter.

PURPOSE: To assess the technical and clinical success of the over-the-wire (OTW) Greenfield inferior vena caval (IVC) filter. MATERIALS AND METHODS: Prospective evaluation of the OTW Greenfield filter in 47 patients was performed during the course of 18 months. Technical success and deployment problems were documented. Caval perforation, leg asymmetry, and tilt were evaluated with a postprocedure, noncontrast computed tomographic (CT) scan. Follow-up was performed at 6- and 12-month intervals after the procedure and included a clinical history, chart review, and magnetic resonance (MR) imaging examination of the IVC. RESULTS: Ninety-one percent of filters were placed without technical difficulties and 100% were successfully deployed. Technical difficulties included sheath kinking prior to deployment (n = 3), initial incomplete filter opening (n = 1), and wire entrapment within the filter (n = 1). Of 38 patients evaluated with CT, there was no case of caval perforation. Twenty-one patients (55%) demonstrated tilt and 14 (37%) had leg asymmetry. Tilting occurred more frequently when the filter was placed from a femoral approach (51%) than from a jugular approach (12%). Of patients with leg asymmetry, the vena cava was narrow in anteroposterior (AP) dimension in five (36%). Of 13 deaths, none were attributed to pulmonary embolism. One patient (2%) had a recurrent pulmonary embolus. Two of 16 patients (12%) with MR imaging follow-up had documented IVC thrombosis. CONCLUSIONS: The OTW Greenfield filter has an effective delivery system, with few difficulties encountered during deployment. Filter tilt and leg asymmetry are common. The etiology of leg asymmetry is likely multifactorial but is often associated with a cava with a small AP diameter. Because OTW deployment appears to offer no benefit in centering the filter, the authors have elected to remove the wire prior to filter deployment to avoid possible entanglement. MR imaging follow-up reveals an acceptable incidence of IVC thrombosis.