Maria Lucia Zanetti

MR arthrographic variability of the arthroscopically normal glenoid labrum: qualitative and quantitative assessment.

Abstract The purpose of this study was to assess qualitatively and quantitatively the MR arthrographic variability of the arthroscopically normal glenoid labrum. Form and signal abnormalities of arthroscopically normal labral parts were analyzed on axial and coronal MR arthrograms of 55 consecutive patients (mean age 43.8 years, age range 21–76 years) referred mainly for suspected rotator cuff lesions. Length and width of the labrum were measured. One hundred twenty-one of 241 (50 %) arthroscopically normal labral parts demonstrated normal (low) signal intensity and normal form on MR arthrograms. Increased linear or globular signal intensity was present in 74 of 241 (31 %) normal labral parts, deformed or fragmented labra in 28 (12 %), complete separation of the labrum from the glenoid in 4 (2 %), a cleft in 5 (2 %), attenuation in 4 (2 %), and complete absence in 5 (2 %), respectively. The mean size of the normal labrum varied between 3.8 × 3.3 mm at the subscapularis bursa level (anteriorly) and 6.1 × 5.6 mm at the inferior portion of the glenoid (anteriorly). The size was not significantly different between arthroscopically normal and abnormal labral parts (p = 0.13–0.83). Since the MR appearance of the arthroscopically normal glenoid labrum varies considerably concerning signal intensity, form, and size, only major tears or detachments of the labrum should be diagnosed.

Radiographically negative stress-related bone injury : MR imaging versus two-phase bone scintigraphy

Purpose: To assess the diagnostic value of MR imaging relative to two-phase bone scintigraphy in radiographically negative stress-related injuries. Material and Methods: Sixteen consecutive patients presenting with stressrelated bone injuries and normal standard radiographs were examined with two-phase bone scans and MR imaging. MR imaging protocols varied according to the region to be examined. The MR and scintigraphic images were evaluated blindly and separately by respectively two radiologists and two nuclear medicine physicians. The standard of reference was represented by a combination of clinical and scintigraphic findings as well as clinical follow-up. Results: For MR imaging, sensitivity, specificity, and positive and negative predictive values for the presence of stress-related injuries for the two readers were 69/63%, 100/80%, 100/91%, and 50/40%, respectively. Interobserver agreement was good (kappa=0.62). For scintigraphy, all abnormal and normal findings were correctly identified. Conclusion: For patients with clinically suspected stress-related injuries and a low probability of other active bone diseases (such as infection or neoplasm), bone scintigraphy should be the initial imaging modality.

Osteonecrosis diagnosed on MR images of the knee. Relationship to reduced bone mineral density determined by high resolution peripheral quantitative CT.

Purpose: To evaluate if osteonecrosis diagnosed on MR images of the knee relates to reduced bone mineral density (BMD) and may be caused by an insufficiency fracture. Material and Methods: Thirty-two consecutive patients (8 men, 24 women; age range 27–82 years, mean 62 years) with MR findings of osteonecrosis of the femoral or tibial condyle were prospectively included. Trabecular and cortical BMD were measured with high resolution peripheral quantitative CT in the non-dominant distal radius and the tibia of the involved extremity. One tibia was not measured due to posttraumatic deformity. Results: The mean trabecular BMD of the radius was 81% of the young-adult average peak BMD (range 19–160%). The mean cortical BMD in the radius was 86% (range 63–108%). The mean trabecular BMD in the tibia was 92% (range 28–160%). The mean cortical BMD in the tibia was 86% (range 49–132%). The values of the trabecular bone of the distal radius (tibia) were normal in 11 (15) patients, osteopenic in 12 (4), and osteoporotic in 9 (12), respectively. The cortical bone values of the distal radius (tibia) were normal in 12 (13) patients, osteopenic in 12 (12), and osteoporotic in 8 (6), respectively. Conclusion: Osteoporosis and osteopenia are commonly found in patients with osteonecrosis of the knee as diagnosed on MR images. This indicates that for some patients an insufficiency mechanism may be responsible for the MR findings. However, in the patients with normal bone density other reasons for osteonecrosis may be present.

Patient throughput times for orthopedic outpatients in a department of radiology: results of an interdisciplinary quality management program

Abstract. The purpose of this project was to employ quality management methods in order to decrease throughput times for orthopedic outpatients sent to the department of radiology. The following intervals were measured at the onset of the study and after 6 and 12 months: (a) between arrivals at outpatient clinic and radiology counter; (b) between arrival at radiology counter and time of last radiograph; and (c) between time of last radiograph and radiology report printing time. After the initial measurement, numerous changes were initiated both in radiology and in orthopedic surgery. The mean interval between arrival at the outpatient clinic and in radiology decreased by one third from 60 min during the first measurement to 40 (p < 0.001) and 41 min during the second and third measurement. The proportion of patients with total radiology times of more than 30 min decreased from 41 to 29 % between the first and third measurements (p < 0.001). The corresponding results for radiology times of more than 45 min were 17 and 11 % (p = 0.03). A standard type of quality management program can be employed successfully in order to reduce radiology throughput times for orthopedic outpatients.