Interactive MR-guided biopsies of the thyroid gland: validation of a new method

The aim of this study was to demonstrate the clinical feasibility and utility of an interactive MR-guidance system to target and biopsy thyroid lesions, and to compare resolution between ultrasound and interventional MR imaging in the evaluation of thyroid lesions. Twenty thyroid lesions of 18 patients were interactively biopsied using a 0.5-T superconducting open magnet system. Stereotactic localization of the needle and imaging was accomplished using T1-weighted gradient-recalled-echo (GRE) images. Representative cytological material was retrieved in 16 of 20 lesions (benign cystic or colloid goiter: n = 14; one de Quervain's thyroiditis and one follicular neoplasia). Lesions smaller than 1.5 cm detected by ultrasound could not be visualized adequately on GRE images. Lesions smaller than 1.5 cm were successfully biopsied by ultrasound (three colloid and haemorrhagic goiters and one adenoma). Magnetic-resonance-guided interactive biopsies and positioning of non-ferromagnetic needles in the thyroid gland are technically feasible and safe. Compared with high-resolution ultrasound, lesions larger than 1.5 cm can be adequately visualized and biopsied. Magnetic-resonance-guided placement of non-ferromagnetic needles is no substitute for high-resolution ultrasound in clinical work-up of thyroid lesions. Received 1 December 1997; Revised 3 February 1998; Accepted 4 February 1998     

Pitfalls in using the ring finger test alone for the diagnosis of carpal tunnel syndrome

Latency differences (>0.5 ms) of median and ulnar sensory action potentials (mSAP and uSAP) at the wrist evoked by ring finger stimulation are considered a sensitive and specific test for diagnosis of carpal tunnel syndrome (CTS). In this study, we aimed to assess the practical usefulness of the ring finger test (RFT) in routine electromyography (EMG) examinations. We investigated 2 series of patients: in the first prospective series we considered 300 hands affected by only mild CTS; in the second series we examined retrospectively the EMG charts of 961 hands affected only by CTS but not selected for severity or duration of symptoms. In the first series we found pathological RFT scores in 87% of cases, and pathological RFT or mSAP latency results in 92%. In the second series, pathological RFT scores were found only in 55% of cases, while in 20% where mSAP failed, a volume conducted uSAP had been erroneously interpreted as arising from the median nerve. RFT sensitivity tested in routine EMG examinations of unselected hands affected by CTS drops considerably. Fingers innervated by one only nerve, such as the index and the little fingers, must also be investigated to increase the diagnostic value of RFT.

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Sommario La differenza (>0.5 ms) tra le latenze distali dei potenziali sensitivi di mediano e ulnare (mSAP e uSAP) registrati al polso ed evocati per stimolazione al quarto dito (ring finger test, RTF) viene considerato un test sensibile e specifico per la diagnosi di sindrome del tunnel carpale (CTS). Sono state studiate 2 serie di pazienti: nella prima serie prospettica abbiamo esaminato 300 mani affette da CTS lieve, in cui mSAP e uSAP dopo stimolazione al quarto dito potevano essere chiaramente differenziati. Il RFT era patologico nell'87%. Considerando insieme il risultato del RFT e il valore assoluto della latenza distale del mSAP dal quarto dito, almeno uno dei test era patologico nel 92% dei casi. Nella seconda serie sono stati esaminati retrospettivamente i referti EMG di 961 mani non selezionate affette esclusivamente da CTS. Attraverso il solo RFT solo il 55% delle diagnosi sarebbero state classificate correttamente, perchè in 20% un uSAP volume condotto era stato erroneamente interpretato come proveniente dal mediano. Dita innervate da un solo nervo come il secondo dito ed it quinto dito devono essere esaminate per aumentare il valore diagnostico del RFT in esami di routine.

     

Estimation of urinary unconjugated androstenedione, dehydroepiandrosterone, testosterone, cortisol, aldosterone and 18-hydroxycorticosterone as a potential tool for assessing adrenal status

A method is described for the simultaneous assay of non-conjugated androstenedione, dehydroepiandrosterone, testosterone, cortisol, aldosterone and 18-hydroxycorticosterone in urine. The method involves solid-phase extraction, automatic high performance liquid chromatography and subsequent radioimmunological quantitation of the individual steroids. Excretion rates of these urinary free steroids were determined in normal males and females. There were no significant sex differences in excretion rates, although both urinary free testosterone and dehydroepiandrosterone were distinctly lower in females than in males. Representative measurements of the excretion rates of patients with Cushing's disease, Addison's disease, ectopic corticotropin syndrome and hirsutism were made. The present method has been shown to be well suited for routine purposes. Its final diagnostic significance for monitoring alterations in glucocorticoid, mineralocorticoid and androgenic activity of the adrenal cortex has yet to be explored.     

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