Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations

Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm.     

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.     

A midface swelling in a child – A possible diagnostic dilemma

A lump on the midface of a child can pose as a diagnostic dilemma. There is a wide variety of possible differential diagnoses, ranging from simple benign conditions such as a sebaceous cyst, dermoid cyst, lipoma, neuroma and neurofibroma, to potentially devastating conditions such as odontogenic myxoma.A case of a child in which the formulation of a definite diagnosis was clinically and histologically challenging is presented.     

Relative permeability of nasal, tracheal, and bronchoalveolar mucosa to macromolecules in rats exposed to ozone

Nasal, tracheal and bronchoalveolar injuries resulting from acute ozone exposure of rats were investigated by permeability changes. 99mTc-labeled diethylenetriaminepentaacetate (DPTA) and 125I-labeled bovine serum albumin (BSA) were selectively instilled into localized airway regions of anesthetized rats exposed to 0.8 ppm 03 or clean air for 2 h. Transmucosal transfer of the radiolabeled tracers was detected by counting the radioactivity in blood samples collected at short postinstillation time intervals. Permeability measurements were made on d 0, 1, and 2 after O3 exposure to analyze the extent and persistence of tissue injury in the nasal, tracheal, and bronchoalveolar regions. Normal mucosal permeability was low in nose, intermediate in bronchoalveolar zone, and high in trachea. The O3-related injury, reflected by elevated permeability, was substantial in the trachea and bronchoalveolar zone but was minimal in the nose immediately after the exposure. Abnormal permeability persisted for less than 24 h in the trachea but for more than 24 h in the bronchoalveolar zone. The results are consistent with the properties of O3 of causing greater injury in the smaller airways and the alveolar zone than in the trachea.