Biomedical subjects
Publications and source records attributed to P Prassopoulos.
We describe a case of Hodgkin's disease with cervical lymphadenopathy which may easily be confused with a granulomatous process both radiologically and pathologically.
PURPOSE: To develop a technique of projectional computed tomographic (CT) cholangiopancreatography (CTCP). MATERIALS AND METHODS: Sixty-one patients underwent CT for suspected biliary or pancreatic abnormalities. The axial CT and CTCP techniques included spiral scanning during the portal venous phase and thick-slab minimum intensity projections. Visualization of pancreatic and extrahepatic bile ducts (divided in five duct segments per patient) was graded blindly on a scale of 1-5 by a consensus of two radiologists. Two hundred seventy-seven duct segments were used to compare axial CT and CTCP in the depiction of duct segments and dilatation; 109 segments were used to compare CTCP with ERCP. RESULTS: Fifty-six of 277 duct segments were not visualized on axial CT images; 15 segments were not visualized on CTCP images (P < .001). There was no statistically significant difference between the number of segments missed with ERCP and the number missed with CTCP: nine and three of 109 segments, respectively. Duct visualization was equal on axial CT and CTCP images in 35 of 109 duct segments and was superior on CTCP images in all but one of the remaining segments (P < .001). Duct visualization on CTCP images was equal to that on ERCP images in 35 segments, superior in nine, and significantly inferior in 66 (P < .001). CONCLUSION: CTCP improves CT depiction of pancreatic and bile ducts with a quality that approaches that of ERCP.
Endoluminal virtual computed tomographic (CT) cholangiopancreatoscopic views of the pancreatic and common bile ducts were generated in 16 patients by using helical CT data sets and endoscopic three-dimensional reconstruction images. In all patients with ductal dilatation, virtual images were obtained and findings correlated with those at helical CT and endoscopic retrograde cholangiopancreatography. Virtual CT cholangiopancreatoscopy is a feasible technique, and initial experience shows promising results.
OBJECTIVE: We sought to determine whether IV contrast material would layer dependently within the abdominal aorta if administered from a location and at a rate routinely used for CT angiography. SUBJECTS AND METHODS: In 22 patients, three equal-sized regions of interest (ROIs) were symmetrically spaced across the abdominal aortic lumen at the level of the celiac axis. These positions corresponded to a dependent, a central, and a nondependent position. Time-enhancement curves were generated for each ROI after IV injection of 10 ml of nonionic contrast material, which was administered at a rate of 3.5 ml/sec, through an antecubital vein. The magnitude of and the time to peak enhancement for each ROI were determined. The 22 peak enhancement values obtained for each of the three ROIs were compared using the Newman-Keuls test. RESULTS: A statistically significant increase in peak enhancement was identified when traversing the abdominal aortic lumen from the nondependent to the central ROI (p < .05) and from the central to the dependent ROI (p < .01). Levels of mean peak enhancement were 48.3+/-19.0, 38.9+/-18.2, and 33.0+/-19.7 for the dependent, central, and nondependent ROIs, respectively. The amount of time needed to reach peak enhancement of each of the three ROIs in an individual patient was similar. CONCLUSION: A small dose of contrast material administered IV through an antecubital vein will layer dependently in the abdominal aorta--thus creating a gradient in enhancement--despite mixing in the heart. If layering of contrast material is subsequently detected during routine abdominal CT angiography, then patient positioning may need to be adjusted to maximize enhancement of targeted vessels.
Purpose: To assess the shortest time for catheter removal with regard to the transhepatic or transperitoneal approach in patients undergoing percutaneous cholecystostomy (PC).Methods: In this prospective study, 40 consecutive high-risk patients with acute cholecystitis (calculous, n = 22; acalculous, n = 18) underwent PC by means of a transhepatic (n = 20) or transperitoneal (n = 20) access route. In 28 patients (70%) computed tomography was used for puncture guidance, while in the remaining 12 (30%) the procedures were performed under ultrasound control. A fistulography was performed on the 14th postprocedural day in all patients and was repeated weekly if the tract was found to be immature. The catheter was removed only if a mature tract without evidence of leakage was delineated.Results: In 36 of 40 patients the procedure was technically successful (90%). Three of the unsuccessful punctures were attempted transperitoneally and one transhepatically. Thirty-five of 36 patients showed rapid improvement within the first 48 hr following the procedure (96%). Three of them died of their severe underlying disease (7.5%) and in another three the catheter was accidentally removed prior to the first fistulography (7.5%). A total of 30 patients could be fully evaluated after the procedure: 15 with a transhepatic, and 15 with a transperitoneal PC. Whereas 14 of 15 patients (93%) with transhepatic gallbladder access developed a mature tract after 14 days and the remaining patient after 3 weeks, only 2 of 15 patients (13%) with a transperitoneal route presented a mature tract after 2 weeks (p < 0.0001; chi2 test with Yates' correction). Eleven patients (73%) with transperitoneal access required 3 weeks and two patients (13%) 4 weeks for complete tract formation.Conclusion: A period of 2 weeks suffices for the majority of patients to develop a mature tract when the transhepatic access route is used; when using the trans- peritoneal route at least 3 weeks are required. We suggest that the transhepatic route is preferable since it allows earlier removal of the catheter and reduces the incidence of complications and discomfort for the patients.
It has been shown that intrathecal chemotherapy may cause brain damage, which can be depicted in neuroimaging studies. The aim of this work was to examine possible morphologic alterations in the brain of children with extracranial solid tumors, without CNS complications, treated with systemic chemotherapy. Brain CT images of 69 children with extracranial malignancies were reviewed and the extent of 12 CSF compartments was measured in 49 CT examinations performed during intravenously given chemotherapy and in 20 after therapy completion. Measurements were compared with corresponding normative data. About half of the children undergoing chemotherapy and half of the patients examined after treatment were found to have diffuse brain atrophy. Focal lesions that might be associated with therapy toxicity were not observed. Chemotherapy, even when administered via the systemic route, may cause brain damage, which is observed long after the end of treatment.
The purpose of our study was to examine variations in normal splenic size in relation to age, gender and body habitus in vivo, and to determine normative data for splenic volume on CT. The width (W), length (L), thickness (Th), cross-sectional areas and volume (Vol) of the spleen were obtained from abdominal CT examinations of 140 patients who underwent CT for indications unrelated to splenic disease. Splenic volume did not vary significantly (-0.04 < r < 0.05, p > 0.10) with the patient's age, gender, height, weight, body mass index or the diameter of the first lumbar vertebra, the latter considered as representative of body habitus on CT. The mean value of the measured splenic volume (S Vol) was 214.6 cm3 with a range from 107.2 to 314.5 cm3. S Vol correlated well with all the linear and the maximal cross-sectional area measurements and could be calculated using the formula: S Vol = 30 + 0.58 (W x L x Th.). Employing the same formula splenic volume was reliably assessed in 47 patients with clinically evident splenomegaly. Quantitative assessment of splenic volume might be of value in assessing mild variations in splenic size, because splenomegaly is the most common manifestation of splenic involvement in many disorders.
PURPOSE: The aim was to select an optimal technique for low-dose high-resolution CT of the sacroiliac joints (SJ). MATERIAL AND METHODS: Dose measurements were performed on a Rando anthropomorphic phantom using thermoluminescence dosimeters for 4 CT protocols and 2 conventional radiography protocols used for SJ evaluation. Six available reconstruction algorithms were tested on CT protocols using 285-665 mAs and 120 or 130 kVp settings and noncontiguous 1.5-mm-thin sections with 3.5-mm intervals. Settings with optimum performance on phantom tests were also applied in a series of 10 patients with SJ arthropathies. RESULTS: A CT protocol using 120 kVp/175 mA/2.9 s/1.5-mm slice thickness/5-mm table increment implied the lower radiation dose among all examination protocols tested and provided high image quality of the SJ. A reconstruction algorithm yielding images of improved spatial resolution with acceptable noise was selected. CONCLUSION: A high spatial frequency reconstruction algorithm, and 120 kVp and 508 mAs were considered optimal for a low-dose CT examination of the SJ that employed narrow (1.5 mm) slice images with interspacing.
We reviewed 181 brain CT examinations, with no abnormal findings, to determine normative data for the posterior cranial fossa (PF) in children. The volume of the PF and the supratentorial cranial cavity (SC) was assessed by summing consecutive CT cross-sectional areas. Linear measurements of the PF structures-cerebellum, vermis, brain stem and fourth ventricle were also performed. The PF grows rapidly during the first 3 years of life and thereafter a smaller increase in size is observed. All the PF structures showed a positive correlation with the PF volume. The PF volume increased in parallel with that of the SC and the PF/SC volume ratio remained relatively constant during childhood. The establishment of normative data for the volume of the PF and its contents may be of value in the CT study of diseases associated with morphological alterations in the PF.
RATIONALE AND OBJECTIVES: The authors evaluate quantitatively brain atrophy induced by central nervous system prophylaxis in children treated for acute lymphoblastic leukemia during and after therapy completion. METHODS: Measurements of the width of the subarachnoid compartments were performed in 243 brain computed tomography (CT) examinations of 196 children examined during (125) and/or after (71) treatment for acute lymphoblastic leukemia without central nervous system involvement. Data were compared with normative data. RESULTS. Diffuse brain atrophy was observed in 74% and 65% of the CT examinations performed during and after cessation of treatment, respectively. The highest incidence of brain atrophy (78%) occurred during the administration of intrathecal chemotherapy. All children younger than 2 years of age exhibited brain atrophy. CONCLUSIONS: Brain atrophy is the principal CT finding in the majority of children treated for acute lymphoblastic leukemia and it can be attributed mainly to intrathecal chemotherapy. This finding can be observed long after therapy completion.
The aim of this study was to assess quantitatively the size of the subarachnoid space in children with "idiopathic" mental retardation. The extent of various cerebrospinal fluid compartments was measured in 106 brain computed tomographic examinations of children with idiopathic mental retardation, and the results were compared with the corresponding normative data. The third ventricle was enlarged in 77% of the cases. A mild degree of diffuse widening of the subarachnoid spaces was found in about 30% of the patients. These morphologic alterations are additional observations supporting the hypothesis that "idiopathic" mental retardation has a biologic basis.
The aim of this study was to quantify the intra- and extraventricular cerebrospinal fluid (CSF) spaces in children with benign enlargement of the frontal subarachnoid space (BE). The infra- and supratentorial CSF compartments were measured in 61 CT examinations of children with BE, 3-27 months old, and compared with those of 96 CT examinations considered normal. Measurements of the ventricular system, and the pontine and chiasmatic cisterns were related to cranial size. In all children with BE the lateral and third ventricles were dilated and the chiasmatic cistern was widened. The subarachnoid space was wider than the upper limits in the control group, in the frontal region (4 mm), and the anterior interhemispheric (4 mm) and Sylvian (3 mm) fissures. The infratentorial CSF compartments, the occipital subarachnoid space, the posterior part of the interhemispheric fissure and, in most cases, the cortical sulci were normal in size in children with BE. The majority were macrocephalic or had rapid head growth but there were also normocephalic children with normal head growth. The size of the posterior fossa was within the normal range in all children with BE. Idiopathic BE is not uncommon in children up to about 3 years old who are healthy or have minimal neurological disturbance and is characterised by a specific pattern of widening of the supratentorial CSF compartments.
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The extent of the cerebrospinal fluid (CSF) spaces was measured in 247 CT examinations, reported as normal, in children aged 3 months to 14 years. The measurements of the CSF compartments were divided by the sum of the transverse and longitudinal internal cranial diameters in the corresponding CT section, in order to take into account the size and shape of the growing skull. All CSF spaces were relatively larger in the younger (< or = 3 years) than in the older children, but did not differ between boys and girls, since the cranial size was taken into account. The CSF compartments increased in a non-uniform manner during the first 3 years of life, but after the age of four they developed uniformly and in parallel with the growing skull. Measurements of the subarachnoid spaces formed an age-related table, which may be of value when interpreting brain CT examinations of children.
Renal parenchymal thickness was measured at different regions and levels through the kidney in 162 abdominal computed tomography (CT) examinations of children 5 months to 14 years old. The transverse diameter of the first lumbar vertebra (L1) was also measured, in order to take into account the child's body habitus. All patients were examined with an indication other than renal disease and had no abnormal CT findings in the retroperitoneum. Renal parenchyma increased in parallel with the transverse diameter of L1 and did not depend on age or sex in children of the same body format. There were no significant differences in size between the right and the left kidneys. Renal measurements were tabulated on reference tables, as an aid in the assessment of renal parenchymal thickness in children undergoing abdominal CT examination.
The size of the normal spleen was estimated by CT in 153 children examined with indication unrelated to splenic disease. In each patient the width, thickness, length and volume of the spleen were calculated. Measurements were also normalized to the transverse diameter of the body of the first lumbar vertebra. The spleen underwent significant growth during the first 4 years of life and reached maximum size at the age of 13. There was no differences in splenic volume between boys and girls. Splenic thickness correlated best with normal splenic volume. The strongest correlation was also found between splenic thickness and volume in a group of 45 children with clinically evident splenomegaly. Splenic thickness, an easy-to-use measurement, may be employed in everyday practice to represent splenic volume on CT.
Pre- and post-nephrectomy kidney growth was studied by computed tomography (CT) in 32 patients with contralateral renal cancer. Kidney enlargement was assessed by comparing the size of the unaffected kidney, in 32 pre- and 61 post-nephrectomy CT examinations, with the corresponding normal size, determined from 120 CT examinations of binephric individuals with no renal disease. The unaffected kidney was found to be 36% larger 1 month before nephrectomy and 54, 62 and 47% in the 1st, 2nd, and 3rd postoperative year, respectively. Compensatory renal growth was influenced both by contralateral cancer and nephrectomy and did not depend on the patient's age or sex.