Toshiaki Ikeda

Ganglion causing paralysis of the suprascapular nerve: Diagnosis by MRI and ultrasonography

A 26-year-old man had a right infraspinatus muscle weakness and aching of the shoulder due to suprascapular nerve entrapment confirmed by electromyography. MRI revealed a well-defined area of increased signal intensity over the suprascapular notch. An ultrasonogram showed a homogeneous hypoechogenic area at the base of the scapular spine. A diagnosis was made of a ganglion compressing the inferior branch of the suprascapular nerve. After removal of several ganglia, the patient had immediate pain relief, and normal electromyographic findings were obtained 5 months postoperatively.

Isolated paralysis of the infraspinatus muscle

We report six patients with isolated paralysis of the infraspinatus and discuss the diagnosis, pathology, treatment, and outcome over a mean follow-up period of 33 months. Four patients were shown to have space-occupying lesions at the spinoglenoid notch by MRI or ultrasonography or both, and ganglia were confirmed and removed surgically in three, with good results. Ganglia at this site are not uncommon and should be included in the differential diagnosis of patients presenting with shoulder pain and weakness.

Ultrasonography for diagnosis of rotator cuff tear

Abstract In this study the clinical usefulness of ultrasonography in the diagnosis of rotator cuff tears was assessed. One hundred twenty-two patients undergoing preoperative ultrasonography were evaluated surgically. Three different ultrasonographic machines were applied with a 7.5-MHz linear-array transducer. Surgery confirmed a sensitivity of 79% for full-thickness tears and 50% for partial thickness tears. In 73 patients with negative ultrasonographic findings, the specifity was 100% for full-thickness tears and 90% for partial-thickness tears. The diagnostic sensitivity for full-thickness tears of the Hitachi EUB-340 system was significantly lower than those of Hitachi EUB-415 and EUB-515, and thus the former cannot be recommended for detection of rotator cuff tears. The sensitivity with regard to partial-thickness tears was also significantly lower with the Hitachi EUB-340 system as compared to the Hitachi EUB-515. There were no significant differences in false-positive rate among the three machines used. In conclusion, accurate ultrasonographic diagnosis of rotator cuff tear requires a high-resolution machine, as well as considerable experience in interpretation.

Assessment of inflamed synovial membrane in the knee joint by dynamic magnetic resonance imaging

Abstract Dynamic magnetic resonance imaging (dynamic MRI) was used to examine the synovial membrane in the knee joints of 15 patients with rheumatoid arthritis (RA) in order to investigate the relationship between pathological and MRI findings. Signal intensities in the regions of interest (ROI), identified as the synovial membrane of the suprapatellar pouch, were measured on MR images. Signal intensities at various times after the injection of contrast medium Gd–diethylenetriaminopentoacetic acid (Gd–DTPA) were normalized relative to the signal intensity at 80 s, and designated as the normalized signal intensity (NSI). Pathological findings were quantified, and the types of inflamed synovial membrane were classified as either acute or chronic. A significant difference in NSI was observed between acute and chronic types (P < 0.05). Dynamic MRI was capable of classifying acute and chronic RA by measuring NSI 20 s after contrast medium injection. Dynamic MRI was therefore shown to be useful for assessing regional synovial inflammation.