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Biomedical subjects

M P Federle

Publications and source records attributed to M P Federle.

At least 19 recordsLinked to original sources
PubMed1999

Role of spiral computed tomography in the diagnosis of pulmonary embolism in the emergency department.

Recently a debate has developed in the medical community as radiologists in some centers suggest the selective substitution of spiral computed tomography (CT) for ventilation-perfusion (V/Q) nuclear medicine imaging as a screening test for the diagnosis of acute pulmonary embolism. Proponents of spiral CT argue that it is more accurate than the usual practice of combining the (V/Q) scan and the physician's best clinical judgment. V/Q scans classify patients into groups according to the probability of pulmonary emboli, whereas the thrombus is visible with spiral CT. Opponents point out that large-scale patient outcome studies using spiral CT have not been completed, but such information is available for (V/Q) scans. Most clinicians are familiar with the strengths and limitations of an assessment that relies primarily on the (V/Q) scan, because this examination has been available for many years. Although spiral CT does not perform as well as pulmonary arteriography in detecting subsegmental emboli, the importance of smaller peripheral emboli is controversial. This review explores the advantages and disadvantages of investigations currently available for the diagnosis of acute pulmonary embolism from the perspective of the emergency physician, presenting the view that spiral CT is likely to have an increasingly important place in patient evaluation.

Algorithms↗
PubMed1999

End-stage primary sclerosing cholangitis: CT findings of hepatic morphology in 36 patients.

PURPOSE: To determine if there is a significant difference in the hepatic morphology depicted on computed tomographic (CT) scans in patients with end-stage cirrhosis caused by primary sclerosing cholangitis versus that in patients with end-stage cirrhosis caused by other factors. MATERIALS AND METHODS: The frequency of five morphologic findings of the liver parenchyma and two intrahepatic biliary findings identified on CT scans in 36 patients with end-stage cirrhosis caused by primary sclerosing cholangitis were compared with the frequency of the same findings in 472 patients with end-stage cirrhosis caused by other factors. The morphologic findings were lobulation of the liver contour, atrophy of the lateral or posterior hepatic segments, hypertrophy of the caudate lobe, and pseudotumor of the caudate lobe. Lobulation, atrophy, and hypertrophy were subclassified as mild-moderate or severe. The biliary findings were ductal dilatation and calculi. RESULTS: Each of the 11 findings occurred more frequently (P < .05) in patients with primary sclerosing cholangitis than in the other 472 patients. Six findings occurred more frequently (P < .05) in patients with primary sclerosing cholangitis than in patients with cirrhosis caused by any other single agent. CONCLUSION: There is a significant difference in the hepatic morphology observed in patients with primary sclerosing cholangitis-induced end-stage cirrhosis versus that in patients with end-stage cirrhosis of other causes.

Adolescent↗
PubMed1998

Blunt splenic injury in adults: clinical and CT criteria for management, with emphasis on active extravasation.

PURPOSE: To evaluate and determine the relevance of clinical and computed tomographic (CT) criteria, particularly extravasation, for prediction of clinical outcome in adults with splenic injuries. MATERIALS AND METHODS: Retrospective blinded review was performed of the records of 270 patients with splenic injury during a 5-year period. Of these, 120 died or underwent surgery without CT and 150 underwent dynamic bolus-enhanced CT. Fifty of the latter underwent immediate surgery and 100 initially were treated without surgery, according to CT and clinical criteria: morphologic grade of injury, amount of hemoperitoneum, active extravasation, and injury severity score (a clinical measure of multiorgan trauma). RESULTS: Of the clinical criteria, injury severity score had the best correlation with outcome. Of the CT criteria, active extravasation correlated best with the need for splenic surgery. Of 96 patients selected for nonsurgical treatment and who did not have active extravasation, 83 recovered without surgery or other intervention. Nonsurgical therapy failed in 15 of the 100 patients. The splenic salvage rate was 59.3% overall and was 92% among the 100 patients with initial nonsurgical management. CONCLUSION: Standard clinical criteria allow triage of patients into immediate surgery or initial nonsurgical groups. CT criteria, especially absence of active extravasation, can help predict successful nonsurgical management of splenic injuries.

Abdominal Injuries↗
PubMed1998

Frequency and effects of extravasation of ionic and nonionic CT contrast media during rapid bolus injection.

PURPOSE: To determine the frequency and clinical effects of extravasation related to rapid bolus infusion of ionic and nonionic contrast media. MATERIALS AND METHODS: Records of 5,106 computed tomographic studies in adult patients who underwent mechanical bolus injection of contrast medium through a plastic cannula in an upper extremity were retrospectively reviewed. RESULTS: Mean infusion rate was 2.8 mL/sec (range, 1-5 mL/sec). Extravasation occurred in 48 (0.9%) patients, including in four of 928 patients who received the median injection rate (2.5 mL/sec). Injection rate was not correlated with frequency or amount of extravasation. Average age and use of ionic versus nonionic contrast medium were identical in patients with and in those without extravasation. There was no sex difference. Thirty-one patients had extravasation of ionic contrast medium; nine of these had extravasation of at least 50 mL. Seventeen patients had extravasation of nonionic contrast medium; seven of these had extravasation of at least 50 mL. Hyaluronidase infiltration was often used as treatment for larger extravasations (in 10 patients each with extravasation of ionic or nonionic medium). No patient required surgical intervention, and none had severe or permanent long-term effects. CONCLUSION: The frequency of extravasation of contrast medium after mechanical bolus injection is higher than that reported for hand-injection or drip-infusion techniques, but there is no correlation between injection rate and extravasation frequency.

Adult↗
PubMed1997

Enlarged abdominal lymph nodes in end-stage cirrhosis: CT-histopathologic correlation in 507 patients.

PURPOSE: To determine the frequency, distribution, size, and cause of enlarged abdominal lymph nodes in patients with end-stage cirrhosis. MATERIALS AND METHODS: Preoperative computed tomographic (CT) scans from 507 hepatic transplantation patients with end-stage cirrhosis were reviewed for the presence, size, and location of enlarged (short-axis diameter > 1 cm) abdominal lymph nodes. Enlarged lymph nodes were identified and resected at surgery. Resected livers were evaluated for malignant neoplasms. CT findings were correlated with histopathologic results. RESULTS: Enlarged abdominal lymph nodes were detected with CT in 253 (50%) of the patients. The enlarged nodes were 1.1 x 1.1 to 3.0 x 4.5 cm in size and were most common in the portacaval space and porta hepatis. The frequency of enlarged nodes varied according to type of cirrhosis: They were most common in patients with primary biliary cirrhosis (86% [43 of 50]) and least common in patients with alcohol-induced cirrhosis (37% [42 of 113]). Histologic evaluation revealed that the enlarged lymph nodes were due to benign nodal hyperplasia in 251 patients and malignant neoplasm in two patients. CONCLUSION: Enlarged abdominal lymph nodes are common in patients with all forms of end-stage cirrhosis. In the absence of other evidence of malignancy, enlarged nodes in these patients should be considered a benign process, with no additional evaluation warranted.

Adolescent↗
PubMed1997

Cholangiocarcinoma: delayed CT contrast enhancement patterns.

PURPOSE: To determine the usefulness of delayed post-equilibrium-phase contrast material-enhanced images in evaluation of intrahepatic cholangiocarcinoma. MATERIALS AND METHODS: Review of surgical, pathologic, and radiologic records revealed 47 patients with proved cholangiocarcinoma with delayed (6-36 minutes) post-equilibrium-phase contrast-enhanced computed tomographic (CT) scans. Unenhanced, dynamic contrast-enhanced, and delayed images were retrospectively reviewed, and enhancement patterns for cholangiocarcinoma lesions were recorded. Degree of delayed enhancement was compared with that of surrounding liver parenchyma. Patterns of delayed enhancement were characterized as homogeneous or heterogeneous. Enhancement characteristics were correlated with histologic findings. RESULTS: Thirty-five (74%) of 47 patients had tumors with mild or marked hyperattenuating delayed contrast enhancement, of which 18 had tumors with homogeneous hyperattenuating enhancement. In three patients, the only evidence of tumor was on the delayed images. In one patient, the tumor was not definable at any imaging phase. Tumors with delayed enhancement tended to be fibrous; however, degree of contrast material retention did not always correlate with the fibrous content of tumors at histopathologic analysis. CONCLUSION: Delayed tumoral contrast enhancement is a typical feature of intrahepatic cholangiocarcinoma and may aid in the detection and characterization of such lesions at CT.

Adult↗
PubMed1997

Abdominal trauma: use of oral contrast material for CT is safe.

PURPOSE: To determine the potential risk of aspiration pneumonitis associated with use of oral contrast material in computed tomography (CT) performed for evaluation of abdominal trauma. MATERIALS AND METHODS: In 510 consecutive adult patients, a dilute 2.5% solution of diatrizoate meglumine and sodium was administered orally or by means of a nasogastric tube as part of a routine protocol for CT evaluation of acute abdominal trauma. A retrospective review of medical records was performed to determine evidence of aspiration pneumonitis occurring before or after CT. RESULTS: None of the patients had aspiration of contrast material or gastric contents attributable to the CT examination. CONCLUSION: Use of contrast material for stomach and bowel opacification during CT for evaluation of abdominal trauma appears to be safe. Proper preparation and administration of contrast material and control of the patient's airway are essential to ensure the safety of this procedure.

Abdominal Injuries↗
PubMed1997

Hypervascular liver metastases: do unenhanced and hepatic arterial phase CT images affect tumor detection?

PURPOSE: To evaluate the relative roles of unenhanced and hepatic arterial phase (HAP) computed tomographic (CT) imaging in the detection of hypervascular liver metastases. MATERIALS AND METHODS: Eighty-four patients with biopsy-proved liver metastases from hypervascular primary tumors other than hepatocellular carcinoma underwent unenhanced and HAP and portal venous phase (PVP) helical CT studies. Three blinded radiologists evaluated each series of images separately for the number, size, and enhancement characteristics of lesions. Sixty-nine patients had follow-up imaging proof of tumor burden. RESULTS: The three readers detected 381-402 lesions on the PVP images and 397-416 lesions on the unenhanced images. Unenhanced images allowed detection of 72%-80% of the lesions seen on PVP images. They detected 94-137 additional lesions on unenhanced but not PVP images. On the HAP images, 375-395 lesions were identified. HAP images allowed detection of 81%-90% of the lesions seen on PVP images. Forty-five to 78 additional lesions were detected on HAP but not on PVP images. In the 69-patient subset, maximal detection of tumor foci occurred in 94% of patients with unenhanced plus PVP images and in 78% with HAP plus PVP images. Unenhanced plus PVP images allowed detection of 96% of the 322 tumors in the subset population. CONCLUSION: Unenhanced plus PVP CT images allow detection of statistically significantly more hypervascular liver metastases than do HAP plus PVP images or imaging only in the PVP.

Contrast Media↗
PubMed1996

Cirrhosis of the liver: MR imaging with mangafodipir trisodium (Mn-DPDP).

PURPOSE: To evaluate the usefulness of manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (Mn-DPDP) in magnetic resonance (MR) imaging of cirrhotic livers. MATERIALS AND METHODS: Fifty-eight patients (mean age, 58.8 years), 29 with and 29 without cirrhosis, underwent MR imaging before and after intravenous administration of 5 mumol/kg Mn-DPDP. Enhancement effects were assessed quantitatively and qualitatively. Histologic confirmation was obtained in 51 patients. RESULTS: Liver parenchyma in both patient groups enhanced significantly on T1-weighted spin-echo and gradient-recalled-echo (GRE) images (P < .01). However, cirrhotic livers enhanced significantly less than noncirrhotic livers on T1-weighted GRE images (P < .05). Fourteen cirrhotic livers had heterogeneous enhancement of parenchyma; enhancement was more prominent on GRE images. Decreased enhancement was seen in patients with confluent fibrosis (n = 5), diffuse fibrosis (n = 6), and siderotic regenerating nodules (n = 4). Increased enhancement was seen in patients with benign regenerating nodules (n = 4). CONCLUSION: Mn-DPDP is useful in patients with cirrhosis.

Case-Control Studies↗
PubMed1996

Hepatocellular carcinoma: MR imaging with mangafodipir trisodium (Mn-DPDP).

PURPOSE: To determine the efficacy of manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (DPDP) at magnetic resonance (MR) imaging for evaluation of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: MR imaging at 1.5 T was performed in 20 patients with 65 HCC nodules. T1- and T2-weighted spin-echo and T1-weighted gradient-recalled-echo images were obtained before and after administration of 5 mumol/kg Mn-DPDP. Readers individually evaluated the pre- and postcontrast images for detection of tumor nodules, with subsequent consensus reading for interpretation discrepancies. Quantitative measurements of tumor-liver contrast-to-noise ratio (C/N) were also performed. Enhancement characteristics were correlated with histologic tumor differentiation. RESULTS: Precontrast images depicted 50 lesions in 17 patients, and postcontrast images depicted 49 lesions in 20 patients. Combination of pre- and postcontrast images enabled detection of 53 lesions in 20 patients. Three lesions (three patients) were seen only on postcontrast images. Four lesions (three patients) were seen only on precontrast images. Reader evaluation of tumor conspicuity showed a significant preference for precontrast T2-weighted SE images (P < .01). Quantitative evaluation showed a significant increase in C/N on postcontrast T1-weighted images (P < .01). Well-differentiated lesions showed significantly greater enhancement than that of poorly differentiated lesions (P < .05). CONCLUSION: Mn-DPDP-enhanced MR imaging depicts HCC tumors not visualized with unenhanced studies. The degree of tumor enhancement correlates with histologic differentiation.

Adult↗
PubMed1996

Detecting hepatocellular carcinoma: value of unenhanced or arterial phase CT imaging or both used in conjunction with conventional portal venous phase contrast-enhanced CT imaging.

OBJECTIVE: Because rates of detection of hypervascular neoplasms by conventional dynamic incremental-bolus CT are lower than rates of detection of hypovascular tumors by CT and because both unenhanced CT imaging and arterial phase helical CT imaging may increase the detection of hypervascular tumors, such as hepatocellular carcinoma, we evaluated the value of unenhanced and arterial phase CT imaging used in conjunction with conventional portal venous phase CT imaging in patients with hepatocellular carcinoma. MATERIALS AND METHODS: Unenhanced and biphasic helical contrast-enhanced CT studies were performed on 81 patients with proven hepatocellular carcinoma. Arterial phase and portal venous phase images were obtained at 20-50 sec and at 60-100 sec, respectively. Three blinded readers evaluated portal venous phase images for the number of liver lesions. On separate dates, the readers compared the arterial phase images with the portal venous phase images and the unenhanced images with the portal venous phase images. The readers recorded the number of lesions that were seen on portal venous phase images and that were also detected on unenhanced or arterial phase images as well as the number of additional lesions seen on unenhanced or arterial phase images. Consensus readings of unenhanced, arterial phase, and portal venous phase images were obtained in the 42 patients who had definitive surgery or follow-up CT scans, documenting the total tumor burden in this patient subgroup. RESULTS: The readers identified 286-310 lesions on portal venous phase images. On unenhanced images, the readers identified 223-244 of the lesions seen on portal venous phase images and an additional 45-55 lesions that were not seen on portal venous phase images. Arterial phase imaging revealed 245-269 of the lesions seen on portal venous phase images and an additional 89-111 lesions that were not seen on portal venous images. The diagnosis of tumor was possible only on unenhanced images in two (3%) of 81 patients and only on arterial phase images in seven patients (9%). In the subset of 42 patients with proof of tumor burden, 157 proven lesions were found. Consensus readings identified 127 (81%) of these lesions on portal venous phase images, 98 (62%) of these lesions on unenhanced images, and 120 (76%) of these lesions on arterial phase images. Of the 30 lesions not seen on portal venous phase images, nine were seen on both unenhanced and arterial phase images, three were seen on unenhanced images only, and 18 were seen on arterial phase images only. CONCLUSION: In patients with known or suspected hepatocellular carcinoma, the use of unenhanced or arterial phase images or both in addition to conventional portal venous phase images resulted in more tumors being detected. The combination of arterial phase and portal venous phase images revealed significantly more hepatocellular carcinoma lesions than did the combination of unenhanced and portal venous phase images.

Adult↗
PubMed1995

Use of oral contrast material in abdominal trauma CT scans: is it dangerous?

OBJECTIVE: To determine the potential risks of the use of oral contrast medium for bowel opacification in abdominal trauma computed tomography (CT) scanning. DESIGN: A retrospective chart review. MATERIALS AND METHODS: 506 consecutive patients who had CT evaluation of acute blunt abdominal trauma. All had both intervenous and "oral" administration of iodinated contrast material. Alert cooperative patients drank 450 ml of a 2.5% solution of Gastroview, while obtunded or uncooperative patients had the same volume and concentration of medium administered through a nasogastric tube, following endotracheal intubation. RESULTS: No patients had aspiration of the contrast medium or gastric contents attributable to performance of the CT scan, except for one patient who had inadvertent installation of contrast through a tube that had been placed into the right main bronchus rather than the stomach. CONCLUSIONS: Bowel opacification is important for optimal CT evaluation of abdominal trauma and can be used with confidence. Attention to proper preparation and administration of the contrast material and, more importantly, control of the patient's airway by appropriate tracheal intubation are essential to assure the safety of the procedure.

Abdominal Injuries↗
PubMed1995

Milestones and future trends in solid organ transplantation.

The past 35 years have been marked by tremendous progress in our understanding of the biologic basis for solid organ graft rejection and acceptance. Although still controversial, solid organ transplantation has become accepted as effective therapy of end-stage disease of the major thoracic and abdominal viscera. Progress has come in small increments and quantum leaps. Better control of immune suppression has been the most critical factor, but improvements in surgical techniques and technical advances, such as better donor organ harvesting and preservation, have played essential roles. The milestones in the development of successful organ transplantation and the current status and challenges are reviewed and the most promising future trends in this exciting field are discussed in this article.

Animals↗
PubMed1994

Sequential viewing of abdominal CT images at varying rates.

PURPOSE: To evaluate radiologists' ability to detect abdominal masses during sequential viewing of series of computed tomographic (CT) scans at varying rates. MATERIALS AND METHODS: Receiver operating characteristic (ROC) analysis was used to assess the ability of five experienced radiologists to determine the presence or absence of subtle abdominal masses in 29 cases (15 positive, 14 negative) while viewing CT scans sequentially at different rates (0.5, 1, 2, 4, 7, and 21 images per second) and also at reader-selectable rates. RESULTS: Even at extremely fast viewing rates (21 images per second), radiologists performed significantly better (P < .05) than would be expected by chance alone (average area Az under the ROC curve = 0.73 vs 0.5). As the viewing rate decreased, their performance increased. The reader-selectable mode was better than any fixed-rate cine mode (average Az = 0.93). CONCLUSION: Fixed-rate sequential viewing of CT images for the primary diagnosis of subtle abdominal masses should be restricted to no more than one or two images per second, but the reader-selectable viewing mode is preferable to any fixed-rate cine mode.

Humans↗