Materials and Methods: Informed consent was waived by the Institutional Review Board for this HIPAA-compliant study. The study group consisted of 32 skeletally immature patients (25 boys, seven girls; mean age, 14.4 years) with 36 juvenile OCD lesions of the knee and 33 skeletally mature patients (25 men, eight women; mean age, 26.2 years) with 34 adult OCD lesions of the knee. All patients had been evaluated with MR imaging and arthroscopy. MR studies were retrospectively reviewed by two radiologists in consensus to determine the presence of previously described MR imaging criteria for OCD instability (ie, high T2 signal intensity rim, surrounding cysts, high T2 signal intensity cartilage fracture line, and fluid-filled osteochondral defect). Sensitivity and specificity of the criteria were calculated separately for juvenile and adult OCD lesions.
Results: Separately, previously described MR imaging criteria for detection of OCD instability were 0%–88% sensitive and 21%–100% specific for juvenile OCD lesions and 27%–54% sensitive and 100% specific for adult OCD lesions. When used together, the criteria were 100% sensitive and 11% specific for instability in juvenile OCD lesions and 100% sensitive and 100% specific for instability in adult OCD lesions.
Conclusion: Previously described MR imaging criteria for OCD instability have high specificity for adult but not juvenile lesions of the knee.
© RSNA, 2008
]]>Materials and Methods: The study was approved by the Swiss Ethics Committee. A prediction rule was computed by using data from a 3-year prospective multicenter study to assess the predictive value of heel-bone quantitative US in 6174 Swiss women aged 70–85 years. A quantitative US device to calculate the stiffness index at the heel was used. Baseline characteristics, known risk factors for osteoporosis and fall, and the quantitative US stiffness index were used to elaborate a predictive rule for osteoporotic fracture. Predictive values were determined by using a univariate Cox model and were adjusted with multivariate analysis.
Results: There were five risk factors for the incidence of osteoporotic fracture: older age (>75 years) (P < .001), low heel quantitative US stiffness index (<78%) (P < .001), history of fracture (P = .001), recent fall (P = .001), and a failed chair test (P = .029). The score points assigned to these risk factors were as follows: age, 2 (3 if age > 80 years); low quantitative US stiffness index, 5 (7.5 if stiffness index < 60%); history of fracture, 1; recent fall, 1.5; and failed chair test, 1. The cutoff value to obtain a high sensitivity (90%) was 4.5. With this cutoff, 1464 women were at lower risk (score, <4.5) and 4710 were at higher risk (score, ≥4.5) for fracture. Among the higher-risk women, 6.1% had an osteoporotic fracture, versus 1.8% of women at lower risk. Among the women who had a hip fracture, 90% were in the higher-risk group.
Conclusion: A prediction rule obtained by using quantitative US stiffness index and four clinical risk factors helped discriminate, with high sensitivity, women at higher versus those at lower risk for osteoporotic fracture.
© RSNA, 2008
]]>Materials and Methods: The study was institutional review board approved and HIPAA compliant, as appropriate, for the four institutions at which the involved patients were treated. Informed patient consent was obtained, were applicable. Thirty-six male patients (age range, 15–80 years; mean age, 40.2 years) with clinically documented first-time traumatic posterior shoulder dislocation were examined with MR arthrography (18 patients) or conventional shoulder MR imaging (18 patients). Causes of posterior shoulder dislocation were electric shock in one patient, seizure in one patient, and trauma in 34 patients. Hill-Sachs lesions, rotator cuff tears, biceps tendon abnormalities, posterior labrocapsular complex lesions, humeral head translation, and osseous glenoid version angle were evaluated. Spearman rank correlation and Student t test analyses were performed.
Results: In 31 (86%) of the 36 patients, a reverse Hill-Sachs lesion was found. Eleven (31%) patients had a reverse osseous Bankart lesion. Twelve full-thickness rotator cuff tears were seen in seven (19%) patients: four supraspinatus tendon, three infraspinatus tendon, and five subscapularis tendon tears. Six (17%) patients had biceps tendon abnormalities. Posterior labrocapsular complex tears were identified in 21 (58%) patients: 10 (48%) with posterior labral sleeve avulsions and 11 (52%) with reverse Bankart lesions. Twenty-seven (75%) patients had a retroverted scaphoglenoid angle (mean, 4.5°). The mean humeral translation distance relative to the osseous glenoid fossa was –4.8 mm; in 33 (92%) patients, this distance was translated posteriorly.
Conclusion: The MR appearance of traumatic posterior shoulder dislocation was characterized by reverse Hill-Sachs lesions in 86% of patients and posterocaudal labrocapsular lesions in nearly 60% of patients. Full-thickness rotator cuff tears were seen in approximately 20% of patients.
© RSNA, 2008
]]>Materials and Methods: Institutional review board approval was granted for this HIPAA-compliant study, and informed consent was waived. MR imaging studies in 141 patients (134 male patients, seven female patients; mean age, 30.1 years; range, 17–71 years) who had been referred to a subspecialist because of groin pain were reviewed for findings including hernia, pubic bone marrow edema, secondary cleft sign, and rectus abdominis and adductor tendon injury. MR imaging findings were compared with surgical findings for 102 patients, physical examination findings for all 141 patients, and MR imaging findings in an asymptomatic control group of 25 men (mean age, 29.8 years; range, 18–39 years). Sensitivity and specificity of MR imaging for rectus abdominis and adductor tendon injury were determined by using a 2 analysis, and significance of the findings was analyzed with an unpaired Student t test. Disease patterns seen at MR imaging were compared with those reported in the surgical and sports medicine literature.
Results: One hundred thirty-eight (98%) of 141 patients had findings at MR imaging that could cause groin pain. Compared with surgery, MR imaging had a sensitivity and specificity, respectively, of 68% and 100% for rectus abdominis tendon injury and 86% and 89% for adductor tendon injury. Injury in each of these structures was significantly more common in the patient group than in the control group (P < .001). Only two patients had hernias at surgery. At MR imaging, injury or disease could be fit into distinct groups, including osteitis pubis, adductor compartment injury, rectus abdominis tendon injury, and injury or disease remote from the pubic symphysis. Patients with injury involving the rectus abdominis insertion were most likely to go on to surgical pelvic floor repair.
Conclusion: MR imaging depicts patterns of findings in patients with athletic pubalgia, including rectus abdominis insertional injury, thigh adductor injury, and articular diseases at the pubic symphysis (osteitis pubis).
© RSNA, 2008
]]>Materials and Methods: The study was compliant with institutional and legislative requirements; donors had dedicated their body for education and research before death. Multidetector CT and DXA scans were acquired in 178 proximal femur specimens harvested from human cadavers (91 women, 87 men; mean age at death, 79 years ± 10.2; range, 52–100 years). An automated VOI-fitting algorithm was used to calculate BMD and bone mineral content (BMC) in the head, neck, and trochanter from CT findings and pixel distribution parameters. The femur failure load (FL) was determined by using a mechanical test. Quantitative CT BMD, quantitative CT pixel distribution parameters, DXA BMD, and FL were correlated at multiple regression analysis.
Results: Mean precision errors in quantitative CT BMD measurements at segmentation with repositioning were 0.56%, 2.26%, and 0.61% for the head, neck, and trochanter, respectively. For the head, neck, and trochanter, respectively, r values were 0.77, 0.53, and 0.59 for the correlation between quantitative CT BMD and FL and 0.74, 0.55, and 0.65 for the correlation between quantitative CT BMC and FL (P < .001). Values ranged from 0.77 to 0.80 for correlations between DXA BMD and FL and from 0.73 to 0.82 for correlations between DXA BMC and FL (P < .001). In a multiple regression model that included quantitative CT pixel distributions, adjusted multivariate correlation coefficient values for correlations with FL increased to up to 0.88.
Conclusion: Regional BMD of the proximal femur can be determined in vitro from quantitative CT data with high precision by using an automated VOI-fitting algorithm. The best multiple regression model for predicting FL included DXA BMD and regional quantitative CT BMD measurements.
© RSNA, 2008
Supplemental material:
Materials and Methods: Institutional review board approval and informed consent were obtained. Eleven healthy elderly (mean age, 64.0 years ± 6.4 [standard deviation]; six men, five women) and 17 healthy young volunteers (mean age, 30.3 years ± 6.5; seven men, 10 women) underwent muscle BOLD MR imaging of the calf. A fat-suppressed T2*-weighted single-shot multiecho echo-planar imaging sequence was used. Temporary vascular occlusion was induced with suprasystolic cuff compression of the thigh. T2* time courses of the muscle BOLD MR signal intensity were obtained from four calf muscles and were characterized by the following curve parameters: hyperemia peak value, time to peak, and T2* end value after 360 seconds of hyperemia. Differences in these parameters between the two cohorts were assessed by using a Student t test.
Results: Considerably lower T2* maxima were observed in the elderly group during hyperemia (P < .005), with a mean hyperemia peak value of 13.1% ± 3.0 compared with 18.9% ± 4.8 in young healthy adults. Peaking occurred earlier in the elderly group (P < .05), with a mean time to peak of 32.2 seconds ± 10.6 compared with 43.1 seconds ± 10.7 in young adults. Furthermore, the elderly group had a significantly slower decrease of the muscle BOLD signal after the hyperemia peak (P < .001), which led to a higher end value of 8.6% ± 3.0 compared with 2.6% ± 2.1 in the young group.
Conclusion: BOLD MR imaging results of the calf demonstrated statistically significant age-dependent differences in the rate, intensity, and recovery of the postocclusive muscle BOLD signal.
© RSNA, 2008
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