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.     

Solitary rectal ulcer syndrome: findings at barium enema study and defecography

Sixteen cases of histopathologically proved solitary rectal ulcer syndrome were encountered. Fifteen patients underwent barium enema study; in nine cases the findings--including rectal stricture, granularity of the mucosa, and thickened rectal folds-were nonspecific. In six cases the study was normal. All patients had a long history of defecation disorders, and defecography was performed in all. In seven cases, intussusception of the rectal wall was seen; in another case the intussusception was accompanied by a rectocele. One case showed rectal prolapse. In four cases, failed relaxation of the puborectalis occurred and prevented the passage of the bolus; in another case there was abnormal perineal descent. In two patients studies were normal. In patients with defecation disorders, the possibility of this syndrome should be considered. Defecography is the method of choice for establishing the diagnosis.     

Controlled investigation of the amobarbital interview for catatonic mutism.

OBJECTIVE: Clinical reports over the last 60 years suggest that the amobarbital interview is effective in relieving catatonic symptoms. This has never been substantiated with methodologically sound trials. The authors postulated that a randomized blind comparison of intravenous amobarbital and saline would demonstrate the superiority of amobarbital in relieving catatonic mutism. METHOD: The subjects were 20 inpatients with catatonic mutism. They were randomly assigned to either saline (N = 10) or a 5% amobarbital solution (N = 10), and the infusions were administered intravenously at a rate of 1 cc/min or less over 10 minutes by a blinded physician. A second blinded physician administered a semistructured interview during the infusion to control for the effect of suggestion. A third blinded physician rated patient responsiveness, reactivity, and arousal. Any patient who was unresponsive to the initial infusion was crossed over to the other infusion. Interviews were videotaped for determination of interrater reliability. RESULTS: In the initial infusions, six of 10 patients responded to amobarbital and zero of 10 responded to saline. Four of the saline nonresponders responded when given amobarbital. Response was evident by the 4th minute of the amobarbital infusion. Interrater reliability was high. The responders and nonresponders differed significantly in the variance of the weight-adjusted amobarbital dose, and the responders tended to be older and female. CONCLUSIONS: Intravenous amobarbital is superior to saline in relieving catatonic mutism, although only 50% of these patients responded. The nonresponders were distinguished from the responders by a greater variance in the weight-adjusted dose of amobarbital.     

Solitary necrotic nodule of the liver: A riddle that is difficult to answer

Solitary necrotic nodule of the liver is an unusual lesion that is often an incidental finding on abdominal imaging, intraoperative examination, or post mortem. Most reported cases of solitary necrotic nodule have been in males, and over three quarters of these lesions have occurred in the right lobe of the liver. Pathologically, solitary necrotic nodule is a benign lesion characterized by a completely necrotic core that is often partly calcified, surrounded by a dense hyalinized fibrous capsule containing elastin fibres. The ultrasound appearance of solitary necrotic nodule is usually of a “target” lesion with a hyperechoic center, while on CT scan they appear as non-enhancing hypodense lesions that are typical of metastatic adenocarcinoma or peripheral cholangiocarcinoma. The impression of malignancy is further enforced with the finding of necrotic cellular material on biopsy and the macroscopically hard and “gritty” nature of the nodules. Currently, permanent histopathology of solitary necrotic nodules is the only accurate method of diagnosis. However, solitary necrotic nodules are usually of a bilobed or lobulated shape that is unusual for malignant liver lesions, and they often lie in close proximity to hepatic inflow structures. Solitary necrotic nodule should be suspected in liver lesions with this configuration, location, and on a biopsy showing a large amount of necrosis.