Lesions of the rotator cuff footprint: diagnostic performance of MR arthrography compared with arthroscopy

BACKGROUND

To evaluate the diagnostic performance of magnetic resonance arthrography (MR-A) of the shoulder in the diagnosis of rotator cuff tears involving the humeral insertion of the supraspinatus and infraspinatus tendon (footprint), using arthroscopy as the reference standard.

MATERIALS AND METHODS

The study population included 90 consecutive patients with history and clinical diagnosis of instability of the shoulder, rotator cuff tear or posterosuperior glenoid impingement. A total of 108 MR arthrograms were performed, since 18 patients had undergone a bilateral procedure. Arthroscopy, which was performed within 45 days after MR-A, was used as the reference standard. Sensitivity, specificity, accuracy, positive and negative predictive values were then calculated.

RESULTS

Magnetic resonance arthrography showed a sensitivity of 92 % and a specificity of 78 % for the overall detection of tears involving the rotator cuff footprint. The diagnostic accuracy was 90 %, and the positive and negative predictive values were 95 and 64 %, respectively. Ten lesions were non-classifiable on surgery, of which eight were non-classifiable on MR-A also.

CONCLUSIONS

Magnetic resonance arthrography is extremely accurate for the detection and classification of rotator cuff footprint tears. Most of these lesions are articular-sided (partial articular-sided supraspinatus tendon avulsion lesions) with predominance in younger patients and concealed type of tear (concealed interstitial delamination lesions).

Role of 3D MRI with proset technique in the evaluation of lumbar radiculopathy

The aim of this study is to demonstrate the effectiveness of 3-Dimensional Magnetic Resonance Imaging (3D MRI) using the ProSet technique in the diagnosis of lumbar radiculopathy and to compare morphological findings with clinical and neurophysiological data. 40 patients suffering from L5 or S1 mono-radiculopathy caused by a disc herniation were evaluated through preliminary clinical assessment and electromyography (EMG) technique. Both conventional spin-echo sequences and 3D coronal FFE with selective water excitation (ProSet imaging) were acquired. Indentation, swelling and tilt angle of the nerve root were assessed by means of a 3D MR radiculography. 3D ProSet multiplanar reconstructions (MPR) were used for quantitative measurements of L5 and S1 nerve root widths. Widths of the symptomatic nerve root were compared with those of the contralateral nerve. Data were processed using Epi Info 3.3 software (CDC, Atlanta, GA, USA) and were compared through a paired t-Student test. We observed an abnormal tilt angle in 22 patients (57,2 percent, P less than 0.05). Morphologic alterations such as monolateral swelling or indentation of the involved roots were found in 36 patients (90 percent, P less than0.01) using 3D MR radiculography. In 10 patients, EMG revealed more nerve roots involved, while 3D FFE with ProSet technique shows a single root involved. In 2 patients, alterations were demonstrated only through EMG technique. We suggest that 3D MR radiculography can provide more information than other techniques about symptomatic disc herniation, supporting the detection of morphological changes of all nerve segments. 3D FFE with ProSet technique demonstrates high sensibility to exactly identify the level of the root involved and can provide an extremely useful tool to lead a surgical planning.