Biomedical subjects
Publications and source records attributed to B Marincek.
We report the case of a 57-year-old female who developed a large pseudoaneurysm of the right circumflex iliac artery 15 months after renal transplantation. Minimal invasive treatment was successfully performed with ultrasound-guided thrombin injection using the B-flow mode.
BACKGROUND: To demonstrate the improved specificity of liver MRI in diagnosis of focal nodular hyperplasia (FNH) using liver specific contrast agents. METHODS: In a patient after resected adenosarcoma of the uterus a focal nodular hyperplasia was followed. Serial MRI of the liver was performed using first Gd-DOTA, followed by superparamagnetic iron oxide (SPIO) as well as Gd-EOB-DTPA. RESULTS: During the follow-up of FNH specificity of liver MRI improved using liver specific contrast agents. The central scar as well as the pseudocapsule showed different typical contrast uptake using all three methods. CONCLUSION: Serial MRI of the liver with Gd-DOTA, SPIO and Gd-EOB-DTPA can exclude a malignant liver lesion. Liver biopsy of FNH can be avoided with increased specificity of MRI for FNH.
Dynamic sequential 3-second CT scans of human abdominal organs were obtained after an intravenous bolus injection of diatrizoate. Time--density curves obtained from the renal cortex and medulla were compared with similar curves obtained from the aorta, inferior vena cava, muscle, and normal liver. CT scans revealed the changes in density produced by the contrast agent reflecting the differential phases of blood flow in the aorta and inferior vena cava. Changes in density in the liver, muscle, and the cortex and medulla of the kidney undoubtedly were related to vascular and extravascular contrast agent. Renal cortical density increased rapidly after bolus administration and peaked approximately 6 seconds after the peak in aortic contrast and slowly declined over the observation period. Renal medullary density increased slowly and at first remained significantly below the cortex but was slightly above cortical values after 30 seconds. These studies indicate that dynamic CT scanning is an effective way of monitoring the contrast media pharmacokinetics within tissue and that human renal function can be monitored and evaluated by using this technique.
CT attenuation values of kidney V2 carcinomas and normal kidneys in 15 rabbits were obtained before and after the simultaneous administration of an intravenous bolus infection of diatrizoate and an intraarterial bolus injection of norepinephrine or acetylcholine. After 6 micrograms norepinephrine, peak V2 density was 15 Hounsfield units (HU) less and renal cortex peak density 41 HU less than baseline, which resulted in a decrease in V2 contrast enhancement. After 20 micrograms acetylcholine, peak V2 density was 10 HU less and renal cortex peak density 13 HU less than baseline; the magnitude of contrast enhancement remained essentially unchanged.
Iosulamide meglumine, a new intravenous biliary contrast agent, was evaluated as a potential hepatic contrast agent utilizing computed tomographic scanning. Time-density data in dogs were generated following 56.7 and 75.6 mg iodine/kg body weight. The iodine was administered both as an iosulamide meglumine bolus injection and a 0.77 ml/min infusion. The greatest increase in x-ray attenuation (24 HU) was observed within 45 minutes after the 75.6 mg iodine/kg body weight infusion technique, which resulted in excellent hepatic opacification. The long duration of increased x-ray attenuation of hepatocytes produced by iosulamide meglumine would be useful in the CT detection of hepatic mass lesions which do not contain normally functioning hepatic cells.
We conducted a retrospective study to assess the potential of contrast enhanced magnetic resonance (MR) imaging in evaluating adnexal tumors. Sixty patients with a total of 77 pelvic lesions underwent MR imaging at 1.5 T and transabdominal ultrasound (US). Precontrast T1- and T2-weighted and Gd-DOTA enhanced T1-weighted MR images were obtained. Diagnoses were proved by surgery in 57 patients. Of the 77 lesions, 54 masses were of ovarian origin, including 12 malignant disorders. Ultrasound demonstrated the lesions in 92%, whereas the sensitivity of unenhanced T2-weighted and postcontrast MR images was 98 and 96%, respectively. Compared to the T2-weighted images, postcontrast MR imaging showed superior overall tumor delineation, assessment of intratumoral architecture, and definition of tumor origin. Contrast enhancement of tumors did not differ significantly between normal ovary and benign and malignant lesions. All modalities were unable to predict malignancy of complex lesions. Based on our study, US remains the screening modality of choice in the evaluation of adnexal tumors. Contrast enhanced MR imaging may be valuable for assessing complex lesions or when the origin of the mass cannot be determined by US. Using contrast enhanced T1-weighted images instead of T2-weighted images may lead to a significant reduction in acquisition time.
With the advent of open-configuration MR systems, enabling image acquisition in a vertical patient position, MR defecography has become possible. MR defecography permits analyses of the anorectal angle, opening of the anal canal, functioning of the puborectal muscle, and descent of the pelvic floor during defecation. The rectal walls are well delineated on the GRE images, permitting visualization of intussusceptions and rectoceles. The concomitant depiction of structures surrounding the anorectal canal is helpful in the assessment of a spastic pelvic floor and the descending perineum syndrome and in permitting visualization of enteroceles. Dynamic MR defecography is an attractive alternative in the evaluation of defecation disorders.
Primary aldosteronism, Cushing's syndrome and pheochromocytoma are the most frequent endocrine hypertensive disorders. Following biochemical confirmation of the clinical diagnosis, mainly non-invasive imaging techniques are necessary to determine the cause of the hormone excess. Diagnosis of primary aldosteronism is confirmed by analysis of aldosterone and renin in peripheral venous blood. Differentiation between adenoma and idiopathic adrenal hyperplasia usually is achieved by computed tomography and isotope scan. A reliable test for the biochemical confirmation of Cushing's syndrome is the determination of urine-free cortisol. In patients with equivocal results the dexamethasone suppression test is performed. Differential diagnosis between ACTH-dependent Cushing's syndrome (pituitary or ectopic) and primary adrenal disorders can be made by determination of plasma-ACTH and -cortisol. Non-invasive localization procedures include computed tomography of the abdomen, computed tomography or magnetic resonance imaging of the pituitary gland, sonography and isotope scan. Diagnosis of pheochromocytoma is based on elevated catecholamine levels in urine or plasma. The tumor is localized by ultrasound, computed tomography or isotope scan.
The main indication for 131J-cholesterol scintigraphy is primary aldosteronism. The preoperative localization of aldosterone - producing adenomas may be obtained with the non-invasive NP-59 - scintigraphy in 75-85% of the patients. Idiopathic bilateral adrenal hyperplasia is diagnosed correctly in 90-100% of the cases. In Cushing's syndrome scintigraphy of the adrenal cortex is indicated only in specific cases such as very small adenomas, primary nodular adrenal hyperplasia and/or for the localization of ectopic adrenal cortex tissue. A false diagnosis may be caused by asymmetric uptake of the radioisotope in idiopathic bilateral hyperplasia or by unspecific absorption in non - adenomatous adrenal cortex tissue with symmetric uptake in patients with unilateral adenomas.