[High-resolution ultrasonography in the study of carpal tunnel syndrome]. / L'ecografia con alta risoluzione nello studio della sindrome del tunnel carpale.

We investigated the reliability of some US signs in the diagnosis of the carpal tunnel syndrome. We carried out a single-blind study with 13-MHz high resolution probes and electromyography on 132 patients with clinical evidence of the carpal tunnel syndrome; a control group of 20 asymptomatic patients was also submitted to US. Eighty-six of 107 patients with US signs of the carpal tunnel syndrome were then submitted to surgical decompression (resection of the transverse carpal ligament), while the extant 21 patients underwent conservative treatment and clinical follow-up. To diagnose the carpal tunnel syndrome, we considered the following US patterns: median nerve changes (swelling before its entrance into the carpal tunnel and flattening in the tunnel itself), palmar bowing of the flexor retinaculum, thickening of the transverse carpal ligament and increased depth of the carpal tunnel, as measured from the apex of the transverse carpal ligament convexity to the underlying carpal bone. Median nerve changes were unreliable signs and were missing in many cases: only 45 of 107 patients exhibited median nerve swelling before and/or its flattening in the carpal tunnel (42%). Such indirect signs as the thickening of the transverse carpal ligament in chronic cases were demonstrated in 94 of 107 patients with the carpal tunnel syndrome (88%) and canal deepening in all unilateral carpal tunnel syndromes was shown in 92 of 107 patients (87%); both these signs proved to be much more reliable. The palmar bowing of the flexor retinaculum was also difficult to demonstrate in surgical patients or in those with connective tissue fibrosis within the tunnel: this sign was demonstrated in 80 of 107 patients with the carpal tunnel syndrome confirmed with electromyography (75%). Tanzer and Rietze reported median nerve changes observed at surgery in 43% and 66% of their patients, respectively. Recent MR findings in asymptomatic wrists have demonstrated that the normal median nerve has an elliptical shape inside the carpal tunnel. To conclude, high resolution US exhibited 96% sensitivity, 95% specificity and 93% diagnostic accuracy and proved to play a major role in the diagnosis of the carpal tunnel syndrome.

[Role of Doppler color in the differential diagnosis of benign and malignant adenopathies]. / Ruolo del color Doppler nella diagnosi differenziale delle adenopatie benigne e maligne.

The diagnosis of enlarged lymph nodes is of the utmost importance especially in the treatment planning of cancer patients. US yields such morphological findings as node size, longitudinal/transverse diameter ratio, hilum visibility and cortical thickness, which however do not permit the differential diagnosis of benign from malignant forms. Some authors tried to distinguish inflammatory enlargement from metastatic forms on the basis of color Doppler findings, with conflicting and questionable results. We investigated the potentials of color Doppler US in the differential diagnosis of benign and malignant lymph node enlargement using morphological data and flow measurements in lymphatic hilum vessels. The palpable superficial lymph nodes of 70 patients were studied with color Doppler with a linear probe (7.5-10 MHz) equipped for Doppler flow measurements. The largest lymph node was studied in multiple enlargement. The final diagnosis was made with US-guided cytology and/or excisional biopsy. The venous hilar vessels were depicted with color Doppler US in 44/45 patients with lymphadenitis and only in 1/17 patients with metastatic enlargement. Spectral Doppler exams of the hilar arteries showed flows with a wide telediastolic component in lymphadenitis (relative RI:0.58), while flow was rapid and with poor telediastolic component (relative RI:0.84) in metastatic enlargement. Average RI was 0.62 in Hodgkin's lymphomas and 0.71 in all the other lesions. We conclude that the distortion and compression of the main hilar vessels in metastatic lymph node enlargement often prevents color Doppler depiction of venous vessels. Moreover, the compression and distortion of the intranodal capillary network (the "mass" effect) often results in increased RI, as detected with power Doppler in the lymphatic hilum. Even though color Doppler US studies of the hemodynamic changes in the hilar vessels need further validation in larger series of cases, our preliminary results suggest interesting potentials in distinguishing inflammatory from metastatic enlargement, which differentiation remains nevertheless difficult especially in Hodgkin's lymphoma.