Richard E. Brennan

Computed tomography of stress fracture

An athletic young female developed gradual onset of pain in the right leg. Plain radiographs demonstrated solid periosteal reaction in the tibia compatible with stress fracture. She stopped sport activites but her pain continued. Follow-up radiographs of the tibia revealed changes suspicious for osteoid osteoma. Computed tomography (CT) scan demonstrated periosteal reaction, but in addition, lucent fracture lines in the tibial cortex were evident. CT obviated the need for more invasive diagnostic procedures in this patient. In selected cases CT may be useful to confirm the diagnosis of stress fracture when plain radiographic or routine tomographic studies are not diagnostic.

Portal vein gas following air-contrast barium enema in granulomatous colitis-Report of a case

Portal vein gas developed in a patient with granulomatous colitis following air-contrast barium enema. No symptomatology or morbidity could be attributed to the portal vein gas in this patient.

Nonvisualized ("phantom") renal calyx: causes and radiological approach to diagnosis.

A calyx which fails completely to opacify on excretory urography (phantom calyx) is often the harbinger of serious underlying renal disease. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. The pathologic basis for the radiographic findings in each of these entities is described and an overall approach to diagnosis is set forth.

Sequential changes in the CT numbers of the normal canine kidney following intravenous contrast administration. I. The renal cortex.

Using a 30-second computed tomography (CT) scanner, the sequential changes in CT numbers of the kidney were determined in three healthy dogs after intravenous administration of sodium and meglumine diatrizoate and iothalamate. For all contrast media, the mean CT number of the cortex was greatest within 2 minutes of rapid intravenous administration. At doses comparable to those used clinically, a linear relationship was demonstrated between the amount of iodine administered (in mg/kg body weight) and the corrected peak mean CT number of the cortex, such that doubling the amount of iodine caused the corrected peak mean CT number of the cortex to approximately double. Following the peak, the mean CT number of the cortex gradually declined. For all contrast media, the corrected mean CT number to corrected peak mean CT number ratios at 5, 10 and 20 minutes were 58 +/- 3%, 39 +/- 3%, and 28 +/- 5% respectively. Our data suggest that rapid-sequence CT may be a valuable tool for evaluating the physiology of renal contrast media excretion.

Fibrous dysplasia of the facial bones and mandible

Five cases of fibrous dysplasia isolated to the facial bones and mandible are presented. A review of the clinical and roentgen features of facial fibrous dysplasia are described.

CT-determined canine kidney and urine iodine concentration following intravenous administration of sodium diatrizoate, metrizamide, iopamidol, and sodium ioxaglate.

Following 24-hour fasting and fluid deprivation, sequential changes in CT numbers of the canine kidney were determined in 4 dogs, each of whom received, at intervals, IV sodium diatrizoate, metrizamide, iopamidol, and sodium ioxaglate at a dose of 500 mgI/kg body weight. The urinary bladder was catheterized for baseline determination of urine osmolality and, subsequently, urine volume and CT number, CT number of the bladder urine from 0 to 10 minutes and from 10 to 20 minutes post-injection was obtained by scanning known dilutions of urine in vitro. Peak renal cortical enhancement occurred within 2 minutes of bolus injection and was not dependent on the chemical make-up of the contrast agent. Peak medullary enhancement occurred within 3 minutes of bolus injection. Peak medulla CT number following sodium diatrizoate was significantly less than that following metrizamide (P less than 0.025) or iopamidol (P less than 0.01). Peak medulla CT number was significantly less following sodium diatrizoate (P less than 0.01), metrizamide (P less than 0.01) and iopamidol (P less than 0.05) than following sodium ioxaglate. Urine iodine concentrations followed a similar pattern, with significant differences as follows: sodium diatrizoate less than metrizamide = iopamidol less than sodium ioxaglate. It was concluded that the investigational agents metrizamide, iopamidol, and sodium ioxaglate have theoretical advantage for excretory urography. Differences in renal handling of these agents are detectable, with CT scanning as differences in renal medullary enhancement and urine iodine concentration.

Computed tomography of the kidneys

Abstract Computed tomography has assumed an important role in evaluating renal disorders. It is especially suited to the study of masses suspected of containing fat, parapelvic masses, displacement or malposition of the urinary tract and kidneys which are poorly visualized by other means. The need for correlation with clinical findings and other imaging methods is stressed.

Evaluation of adrenal disease by computed tomography

Abstract CT is the imaging modality of choice for screening possible adrenal pathology. It is non-invasive, safe, accurate and widely available. Excretory urography is not a good screening procedure. Ultrasound and radionuclide scanning are complementary procedures which often resolve equivocal or unsatisfactory CT studies. Angiography should be reserved for demonstration of vascular anatomy and/or cases unsolved by other techniques.

Computed tomography of the iliopsoas muscle

Computed tomography (CT) is an ideal method for the imaging of the psoas muscle. The authors present 13 cases of patients with psoas abnormalities diagnosed by CT. The CT features of the different pathologic entities and comparison of CT with other imaging modalities are discussed.

Computed tomography of nonopaque renal pyelocalyceal filling defects: Report of eleven cases

Abstract Eleven patients with nonopaque renal pyelocalyceal filling defects were studied with computed tomography (CT). Final diagnosis was proven by surgery, stone passage, or by radiographic follow-up. Five patients have nonopaque calculi with CT numbers ranging from 171 to 365 HU. Five patients had transitional cell carcinoma presenting as an intraluminal mass (27 to 36 HU), while one had blood clot (30 HU). CT is a valuable diagnostic modality in the investigation of nonopaque pyelocalyceal filling defects. Nonopaque calculus diagnosis is simplified. Differentiation of tumor and blood clot is not possible in all cases, as both may present as intraluminal mass with similar CT numbers. CT findings which may allow differentiation of tumor and blood clot are discussed.