Event-related potential correlates of functional hearing loss: Reduced P3 amplitude with preserved Nl and N2 components in a unilateral case

Abstract A female patient exhibiting functional hearing loss in her left ear demonstrated reduced amplitude of P3 component in event-related potentials (ERP) to left monaural stimulation, with preserved N1 and N2 components to stimulation of either ear. This result suggested that stimuli in the affected ear were conducted successfully up to the auditory cortex but that further processing in higher brain regions was 'repressed'. Event-related potential examination for such hysterical disorders could be useful in clarifying their brain mechanism and offer a useful diagnostic clue to its nature.     

Short-Ti inversion-recovery pulse sequence: analysis and initial experience in cancer imaging

Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy.     

Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.     

Contrast venography, the gold standard for the diagnosis of deep-vein thrombosis: improvement in observer agreement.

To determine whether the Rabinov-Paulin or the long-leg venography technique should be preferred in the diagnostic management of patients with clinically suspected deep-vein thrombosis, two independent experienced radiologists blindly assessed two different series of venograms of consecutive outpatients with clinically suspected deep-vein thrombosis. Venograms were obtained from two outpatient clinics of primary referral centres. In one centre the venograms were performed according to the technique of Rabinov and Paulin with the use of 100 ml of radiographic material and spot films of the calf, popliteal and more proximal veins. In the other centre, long-leg films were obtained after the administration of 150 ml of contrast material. The percentage venograms adjudicated as inadequate by at least one radiologist and inter-observer disagreement for both series were used as the main study outcome measures. Prior to the study, both radiologists agreed on the standardized criteria for a normal, abnormal and inadequate test result using a separate set of films. An inadequacy rate of 20% was found for the Rabinov-Paulin venography series (n = 123), whereas only 2% of the 126 long-leg films were inadequate for interpretation (p less than 0.001). The inter-observer diagreement for inadequacy, presence or absence of deep-vein thrombosis was 21% for the Rabinov and Paulin venograms and 4% for the long-leg films (kappa, 0.65 and 0.92; 95% confidence intervals: 0.53 to 0.77 and 0.84 to 0.99, respectively; p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)