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Biomedical subjects

M P Federle

Publications and source records attributed to M P Federle.

At least 37 records · Page 2Linked to original sources
PubMed2000

Prognostic value of abdominal CT scanning and hepatic histopathology in patients with acute liver failure.

Acute liver failure has extremely high mortality without liver transplantation. We attempted to determine the value of abdominal CT scanning and liver biopsy in its management. A retrospective analysis of patients with acute liver failure was performed; demographic, clinical, radiologic and histopathologic features were noted. Over a period of 13 years, 177 patients were evaluated. The mean age was 39 years and 63% were females. The patients were divided into three groups. Fourteen percent survived with medical management (group I), 37% died (group II), and 49% had liver transplantation (group III). Most patients showed diffuse low density of the liver on CT scanning and the proportions were similar in the three groups. Moderate to large ascites was not present in group I but occurred in 31% of patients in group II and in 15% in group III. Mean hepatic volumes were similar in the three groups; however, 97% of the patients with a liver volume of less than 1000 ml either died or required liver transplantation. Liver biopsies among patients with spontaneous recovery (group I) were distinguished by the presence of regenerative changes and a hepatic parenchymal necrosis of less than 50%. These results suggest that in patients with acute liver failure a liver volume of less than 1000 ml and/or hepatic parenchymal necrosis of greater than 50% is indicative of a poor prognosis. This information may assist decision making in such patients, in particular, regarding the need for liver transplantation.

Adolescent↗
PubMed2000

Wall stress distribution on three-dimensionally reconstructed models of human abdominal aortic aneurysm.

PURPOSE: Abdominal aortic aneurysm (AAA) rupture is believed to occur when the mechanical stress acting on the wall exceeds the strength of the wall tissue. Therefore, knowledge of the stress distribution in an intact AAA wall could be useful in assessing its risk of rupture. We developed a methodology to noninvasively estimate the in vivo wall stress distribution for actual AAAs on a patient-to-patient basis. METHODS: Six patients with AAAs and one control patient with a nonaneurysmal aorta were the study subjects. Data from spiral computed tomography scans were used as a means of three-dimensionally reconstructing the in situ geometry of the intact AAAs and the control aorta. We used a nonlinear biomechanical model developed specifically for AAA wall tissue. By means of the finite element method, the stress distribution on the aortic wall of all subjects under systolic blood pressure was determined and studied. RESULTS: In all the AAA cases, the wall stress was complexly distributed, with distinct regions of high and low stress. Peak wall stress among AAA patients varied from 29 N/cm(2) to 45 N/cm(2) and was found on the posterior surface in all cases studied. The wall stress on the nonaneurysmal aorta in the control subject was relatively low and uniformly distributed, with a peak wall stress of 12 N/cm(2). AAA volume, rather than AAA diameter, was shown by means of statistical analysis to be a better indicator of high wall stresses and possibly rupture. CONCLUSION: The approach taken to estimate AAA wall stress distribution is completely noninvasive and does not require any additional involvement or expense by the AAA patient. We believe that this methodology may allow for the evaluation of an individual AAA's rupture risk on a more biophysically sound basis than the widely used 5-cm AAA diameter criterion.

Adult↗
PubMed2000

Hepatocellular adenoma: multiphasic CT and histopathologic findings in 25 patients.

PURPOSE: To evaluate multiphasic computed tomographic (CT) findings of hepatic adenomas and to correlate these findings with those of histopathologic analysis. MATERIALS AND METHODS: Multiphasic helical CT was performed in 25 patients with 44 hepatic adenomas. Nonenhanced scans were obtained in all cases, along with hepatic arterial-dominant phase (HAP) and portal venous-dominant phase (PVP) images at 25-28 and 60-70 seconds after intravenous contrast material injection at 3-5 mL/sec. Twelve patients with 24 adenomas also underwent delayed-phase (5-10-minute) CT. Two independent readers retrospectively reviewed each case for the number of detectable lesions in each CT phase, morphologic features of tumors, and degrees of enhancement. RESULTS: Thirteen patients had solitary adenomas; 12 patients had two or three adenomas. Both observers agreed on the numbers of lesions detected in all cases and in all phases of enhancement. The detection rate for all 44 adenomas per type of examination was as follows: nonenhanced, 86% (38 of 44); HAP, 100% (44 of 44); PVP, 82% (36 of 44), and delayed, 88% (21 of 24). Tumor margins were well defined in 38 adenomas (86%), and the surface was smooth in 42 adenomas (95%). The right hepatic lobe was the only site of adenoma or was a site along with the left lobe in 29 cases (66%). Tumor fat and calcifications were uncommon (three cases [7%] and two cases [5%], respectively). Other than areas of fat, hemorrhage, or necrosis, the adenomas enhanced nearly homogeneously, especially on PVP and delayed-phase scans. Five patients had coexistent hepatic masses, which were focal nodular hyperplasia (n = 3) or hepatocellular carcinoma (n = 2). CONCLUSION: Hepatic adenomas often have characteristic features at multiphasic CT that may allow their distinction from other hepatic masses.

Adenoma, Liver Cell↗
PubMed2000

Islet cell tumor of the pancreas: biphasic CT versus MR imaging in tumor detection.

PURPOSE: To compare the effectiveness of biphasic computed tomography (CT) and magnetic resonance (MR) imaging in the detection of pancreatic islet cell tumors. MATERIALS AND METHODS: Retrospective quantitative, qualitative, and receiver operating characteristic analyses of biphasic CT and MR imaging were performed in 19 patients with 26 histopathologically proved islet cell tumors. Delayed arterial dominant-phase (AP) and portal venous-phase (PVP) biphasic CT was performed after the administration of contrast material. MR imaging included T1-weighted spin-echo (SE) and T2-weighted SE or fast SE imaging, fat-saturated T1-weighted SE imaging, dynamic contrast material-enhanced T1-weighted gradient-echo imaging, and delayed enhanced T1-weighted SE imaging with or without fat saturation. RESULTS: PVP CT and delayed enhanced T1-weighted MR imaging had the highest A(z) values (0.98 and 0.97, respectively; P <.05). Delayed enhanced T1-weighted MR imaging had the highest relative sensitivity (14-15 [74%-79%] of 19 lesions), followed by PVP CT (18-19 [69%-73%] of 26 lesions), AP CT (17-19 [65%-73%] of 26 lesions), fat-saturated T1-weighted MR imaging (eight to 10 [57%-71%] of 14 lesions), T2-weighted (16-17 [62%-65%] of 26 lesions), T1-weighted (15-18 [58%-69%] of 26 lesions) MR imaging, and dynamic MR imaging (nine [56%] of 16 lesions). CONCLUSION: Biphasic (especially PVP) CT and MR imaging have similar effectiveness in the detection of islet cell tumors if fat-saturated T1-weighted and delayed enhanced T1-weighted MR imaging are included.

Adenoma, Islet Cell↗
PubMed2000

Liver adenomatosis: clinical, histopathologic, and imaging findings in 15 patients.

PURPOSE: To report and correlate the clinical, histopathologic, and imaging findings in 15 patients with liver adenomatosis. MATERIALS AND METHODS: Fifteen adult patients had more than 10 hepatic adenomas each and no history of glycogen storage disease or anabolic steroid use. Ten of them underwent bolus-enhanced dynamic computed tomography (CT) with or without magnetic resonance (MR) imaging, ultrasonography, and/or angiography. RESULTS: Clinical abnormalities included abdominal pain in 11 (73%) and hepatomegaly in 10 (67%) patients, and abnormal liver function in 10 (91%) of 11 patients. The number of adenomas in each patient was 10-50 at imaging, but many more lesions were found in the resected specimens. Hemorrhage was commonly found within adenomas at histopathologic analysis, but only four patients had clinical and imaging evidence of substantial hemorrhage. In all patients, the adenomas increased over time, and two patients developed hepatocellular carcinoma. CT and MR features of the adenomas included evidence of hypervascularity (63%), intratumoral fat (50% of patients at CT, 80% at MR), and decreased conspicuity at portal venous and delayed-phase imaging. Fifty percent of patients had congenital or acquired hepatic vascular abnormalities. CONCLUSION: The imaging and histopathologic features of individual adenomatous lesions are similar to those reported in young women who are taking oral contraceptives. However, the lesions in liver adenomatosis are not steroid dependent but rather multiple, progressive, and symptomatic, and they are more likely to lead to impaired liver function, hemorrhage, and perhaps malignant degeneration.

Abdominal Pain↗
PubMed2000

Fibrolamellar hepatocellular carcinoma: pre- and posttherapy evaluation with CT and MR imaging.

PURPOSE: To determine the features of advanced hepatic and extrahepatic fibrolamellar hepatocellular carcinomas (HCCs) and their effects on immediate surgical management and tumor recurrence. MATERIALS AND METHODS: Thirty-one patients with fibrolamellar HCC underwent pretherapy computed tomography (CT); 11 underwent pretherapy magnetic resonance (MR) imaging. All 40 patients underwent posttherapy CT; four, follow-up MR imaging. Imaging, surgical, and histopathologic findings were correlated. RESULTS: Twenty-five (81%) patients had solitary tumors (mean maximum diameter, 13 cm). Thirteen (42%) patients had intrahepatic biliary obstruction; 27 (87%) patients had involvement of the portal or hepatic veins. Thirteen (42%) had extrahepatic tumor spread, nine (29%) had distant metastases on pretherapy images, and 20 (65%) had lymphadenopathy. Thirty-two (80%) of 40 patients underwent exploration surgery; curative resection was attempted in 25 (62%), including four patients who underwent liver transplantation. Only 17 patients were considered to have had hepatic and extrahepatic tumors completely excised. Tumor recurred in all eight of the 17 patients who had extrahepatic disease at pretherapy CT and in four of the seven patients who seemed to have tumor limited to the liver. A combination of repeat tumor resection and adjuvant chemotherapy resulted in prolonged tumor-free survival in some cases. CONCLUSION: Fibrolamellar HCC frequently demonstrates aggressive local invasion and nodal and distant metastases. Pretherapy and follow-up imaging are important for staging, surveillance, and optimal management. Aggressive surgical resection may be helpful to control fibrolamellar HCC and to prolong survival in appropriately selected cases.

Adolescent↗
PubMed2000

Detection of vascular complications after liver transplantation: early experience in multislice CT angiography with volume rendering.

OBJECTIVE: Our objective was to investigate the usefulness of three-dimensional multislice CT angiography for the evaluation of liver transplant recipients presenting with clinical or sonographic findings suggestive of hepatic vascular complications. CONCLUSION: Our early results indicate that three-dimensional multislice CT angiography with volume rendering can reveal common and potentially lethal vascular complications in patients who have undergone liver transplantation.

Aneurysm↗
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↗
PubMed1999

Fibrolamellar hepatocellular carcinoma: imaging and pathologic findings in 31 recent cases.

PURPOSE: To review characteristic findings of fibrolamellar hepatocellular carcinoma (HCC) at computed tomography (CT) and magnetic resonance (MR) imaging. MATERIALS AND METHODS: The authors retrospectively reviewed the clinical, pathologic, and preoperative imaging findings in 31 patients with histologically proved fibrolamellar HCC. Dynamic contrast material-enhanced CT of the liver was performed in 31 patients, helical multiphase CT in 21, and MR imaging in 11. Complete resection was performed in 17 patients, and imaging-pathologic correlation was performed. RESULTS: Large tumors (mean diameter, 13 cm) were depicted at CT and MR in all cases. At CT, the margins of the tumors were well defined in 24 (77%) of 31 cases calcifications were depicted in 21 (68%), a central scar in 22 (71%), and abdominal lymphadenopathy in 20 (65%). In 20 (80%) of 25 cases with hepatic arterial phase CT images, all tumors were heterogeneous and depicted areas of hypervascularity. At MR imaging, tumors were hypointense to liver on T1-weighted images (n = 11) and hyperintense to liver on T2-weighted images (n = 10). Calcification was not depicted on MR images, but a central scar was depicted as hypointense to surrounding tumor in nine cases. CONCLUSION: CT and MR images demonstrate characteristic features that may allow confident diagnosis of fibrolamellar HCC.

Adolescent↗
PubMed1999

Spectrum of imaging findings of the liver in end-stage cirrhosis: Part II, focal abnormalities.

Cirrhosis, through the process of necrosis, fibrosis, regeneration, and malignant transformation, creates multiple focal benign and malignant hepatic masses. The detection and appearance of these masses varies with the severity of the cirrhotic process and the imaging technique used. Although some overlap exists in the imaging appearance of the benign and malignant masses, in most instances recognition of a few characteristic features will yield the correct diagnosis.

Carcinoma, Hepatocellular↗
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↗