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Biomedical subjects

Michael P Federle

Publications and source records attributed to Michael P Federle.

At least 19 recordsLinked to original sources
PubMed2006

Cirrhosis: CT and MR imaging evaluation.

In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, "pseudo-cirrhosis" due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein.

Humans↗
PubMed2006

Abdominal imaging and intervention in liver transplantation.

Diagnostic imaging and interventional radiology play key roles in the evaluation and management of patients who are being evaluated for potential liver transplantation (LTX) and of those who have received a transplanted liver. Technical advances in imaging equipment and technique allow more accurate assessment and often obviate unnecessary or nontherapeutic surgery or invasive techniques such as catheter angiography.

Angiography↗
PubMed2006

Positron emission tomography/computed tomography: protocol issues and options.

Combined positron emission tomography/computed tomography (PET/CT) became FDA-approved for clinical use in late 2001. There are several design advantages of combined PET/CT over PET and CT acquired on separate devices, including more accurate CT and PET data co-registration, improved lesion localization, consolidation of imaging studies, and reduced scan times compared to dedicated PET. There are several protocols that can used to scan patients on combined PET/CT devices. Although there is no single "correct" protocol for performing a PET/CT scan, the use of oral and intravenous contrast media may improve the diagnostic value of the CT component. Whether to utilize contrast media depends on important clinical variables, including the specific type of tumor and the likelihood of encountering viable abdominal and pelvic malignancy. This article discusses various protocols pertinent to PET/CT imaging, including how the CT portion of a PET/CT scan can be performed and optimized, as well as PET/CT interpretation and reporting issues.

Artifacts↗
PubMed2006

Peliosis hepatis: spectrum of imaging findings.

OBJECTIVE: It is important to recognize the imaging characteristics of peliosis hepatis because peliotic lesions may mimic several different types of focal hepatic lesions CONCLUSION: We illustrate the spectrum of imaging findings of peliosis hepatis, including sonography, CT, MR, and angiography.

Adult↗
PubMed2005

CT of the acute (emergency) abdomen.

Over the past 20 years, CT has become the premier imaging technique for evaluating patients presenting with symptoms of acute, severe, abdominal pain. The advent of multidector helical CT (MDCT) has improved the accuracy and expanded the indications for CT of the acute abdomen. MDCT is accurate for nearly all of the numerous etiologies of conditions that require emergency medical or surgical treatment. The proper execution and interpretation of CT in this setting reduces morbidity, mortality, and medical expenses.

Abdomen, Acute↗
PubMed2005

Double phase CT during hepatic arteriography for diagnosis of hepatocellular carcinoma.

RATIONALE AND OBJECTIVES: The purpose of this study is to assess the diagnostic impact of double phase computed tomography during hepatic arteriography for hepatocellular carcinoma. MATERIALS AND METHODS: 118 hepatocellular carcinomas in 73 cirrhotic patients who underwent double phase computed tomography during hepatic arteriography were enrolled in this study. Double phase computed tomography during hepatic arteriography consisted of computed tomography images obtained at 5-10 s (first phase) and 40-50 s (second phase) after the initiation of an intraarterial administration of 40-60 ml of contrast medium through the hepatic artery. Diagnostic accuracy of the first phase computed tomography during hepatic arteriography alone and double phase computed tomography during hepatic arteriography images for hepatocellular carcinoma were separately analyzed by three blinded readers independently. Alternative-free response receiver operating characteristic curves were constructed to compare each set of computed tomography during hepatic arteriography images. RESULTS: The detection sensitivity of the double phase CTHA for HCC (mean, 83.1%) was significantly higher than that of the first phase CTHA alone (mean, 73.4%) (P < 0.01). Moreover, the positive predictive value of the double phase CTHA (mean, 93.7%) was higher than that of the first phase CTHA alone (87.4%). The area under the AFROC curve (Az value) of the double phase CTHA (mean, 0.88) was significantly higher than that of the first phase CTHA alone (mean, 0.77) (P < 0.05). CONCLUSIONS: Double phase computed tomography during hepatic arteriography can improve the diagnostic accuracy of hepatocellular carcinoma.

Adult↗
PubMed2004

Congenital hepatic fibrosis: CT findings in 18 adults.

PURPOSE: To evaluate the computed tomographic (CT) findings in adult patients with pathologically proved congenital hepatic fibrosis. MATERIALS AND METHODS: This was a retrospective review of congenital hepatic fibrosis cases identified at two institutions over the course of 8 years. Eight men and 10 women with an age range of 22-72 years (mean age, 39 years) were included. Contrast material-enhanced and unenhanced CT scans were obtained through the liver in all patients. Two radiologists evaluated size of and morphologic findings (atrophy or hypertrophy localized according to hepatic segments) in the liver; increased diameter or number of hepatic arteries at the hilum; presence of hepatic nodules, varices, spontaneous splenorenal shunts, and splenomegaly; and association with other hepatic ductal plate malformations and renal abnormalities. RESULTS: Sixteen patients had morphologic abnormalities in the liver, 15 had splenomegaly (three underwent splenectomy for portal hypertension), and 14 had varices or spontaneous splenorenal shunts. An enlarged hepatic artery and a tangle of abnormally enlarged arterial vessels were identified in five and four patients, respectively, and four of these nine patients had large benign regenerative nodules. Ten patients had renal abnormalities and nine had an associated ductal plate malformation. CONCLUSION: This retrospective study shows that certain findings (ie, liver morphologic and associated ductal plate abnormalities, varices, splenomegaly, and renal abnormalities) are frequently observed in combination in patients with congenital hepatic fibrosis.

Adult↗
PubMed2004

Radiographic manifestations of normal postoperative anatomy and gastrointestinal complications of bariatric surgery, with emphasis on CT imaging findings.

Recently, there has been a tremendous increase in the frequency of utilization of surgery to control morbid obesity that is very common and increasing in incidence in Western industrialized nations. Imaging plays an important role in the evaluation and management of patients before and after bariatric surgery. In this article, we discuss the imaging findings relating to bariatric procedures, focusing on the role of computed tomography (CT) in the evaluation of normal postoperative anatomy and gastrointestinal complications.

Anastomosis, Roux-en-Y↗
PubMed2004

Single-detector helical CT in PET-CT: assessment of image quality.

OBJECTIVE: CT in positron emission tomography (PET)-CT imaging is often performed as a single scan from the base of the skull to the groin, potentially resulting in degradation of the quality of CT scans depending on the position of the patient's arms and mode of breathing and the use and timing of IV contrast injection. The aim of our study was to assess the impact of artifacts on the diagnostic quality of CT scans using a single-detector helical CT scanner in PET-CT imaging. MATERIALS AND METHODS: Two radiologists retrospectively evaluated the diagnostic image quality of CT scans obtained with PET-CT in 81 patients with lymphoma. The severity of the artifacts related to the position of the patient's arms beside the body, the influence of breathing motion, and the presence of contrast material in the upper thoracic veins were ranked using a 4-point scale. RESULTS: Performing CT with the patient's arms positioned beside the body resulted in streak artifacts, predominantly in the upper abdomen, that were graded as mild in 22%, moderate in 40%, and severe in 38% of the scans. A patient's weight significantly correlated with the degree of severity of the artifacts (p < 0.05). Shallow breathing by the patient during scanning caused blurring and double-imaging, again predominantly in the upper abdomen, that were graded as mild in 23%, moderate in 49%, or severe in 28% of the scans. In 84% of the CT scans obtained with IV contrast material, the image quality of the upper thoracic region was moderately (27%) or severely (57%) degraded by streak artifacts from highly concentrated contrast material in the upper thoracic veins. CONCLUSION: The use of a single-detector CT scanner in whole-body PET-CT decreases the image quality of CT scans because of streak artifacts that occur predominantly in scans of the upper abdomen. Scanning with the patient's arms raised eliminates the streak artifacts in scans of the abdominal region. With the new generation of PET-CT devices equipped with MDCT scanners, breathing motion artifacts can be expected to be eliminated if protocols for breath-hold CT are applied. Reversing the direction of CT scanning allows one to avoid imaging the thoracic region at a time when undiluted IV contrast material is still present in the upper thoracic veins.

Adolescent↗
PubMed2003

Prevalence of hepatic hemangioma in patients with focal nodular hyperplasia: MR imaging analysis.

PURPOSE: To evaluate the prevalence of hepatic hemangioma in a large population of patients with focal nodular hyperplasia (FNH) and to determine if the prevalence is higher than that in patients with other hepatic masses. MATERIALS AND METHODS: Over a period of 40 months, 247 patients with one or more hepatic masses underwent magnetic resonance (MR) imaging at our institution and met the inclusion criteria for this study. One hundred forty-eight patients received a diagnosis of FNH (study group). Ninety-nine patients had a lesion other than FNH and had no history of chronic liver disease (control group). Imaging findings of the main lesion and presence of associated hemangioma were investigated. chi2 analysis was used to determine if there was a statistically significant difference in the two groups regarding the number of patients with associated masses. RESULTS: Twenty-nine of 148 patients (20%) in the study group had FNH with one or more associated hepatic hemangiomas. Among the 99 patients in the control group, nine (9%) had an associated hemangioma. The prevalence of hemangioma was significantly higher (P <.02) in the study group than in the control group. The prevalence of hemangioma in patients with a solitary FNH lesion compared with that in patients with multiple FNH lesions was not significantly different. CONCLUSION: Patients with FNH are more likely to have an associated hepatic hemangioma than are those with another type of focal hepatic mass.

Adult↗
PubMed2003

Evaluation of responses to chemoembolization in patients with unresectable hepatocellular carcinoma.

BACKGROUND: The authors used computed tomography (CT) scans to correlate the changes in tumor vascularity, necrosis, and size with response and survival after transcatheter arterial chemoembolization (TACE) in patients with advanced, unresectable, hepatocellular carcinoma (HCC). METHODS: The authors studied 72 patients with biopsy-proven, unresectable HCC and focused on 186 individual tumor masses. A baseline, multiphase, helical CT was performed and at least three follow-up CT scans were performed after treatment by TACE. Tumors were classified as hypervascular or hypovascular and patients were classified as responders or nonresponders based on CT evidence of altered tumor size, tumor necrosis, and the appearance of new tumors. A new scoring system was used to monitor patient response to TACE. RESULTS: Thirty-eight patients were responders and 34 were nonresponders. Patient survival was significantly increased (P = 0.009) in patients who were hypervascular responders. Survival also was increased in hypervascular nonresponders compared with hypovascular nonresponders (P = 0.008) and in hypovascular responders compared with hypovascular nonresponders (P = 0.002). Response to chemoembolization was found to be significantly (P = 0.02) and inversely proportional to tumor size, but the number of tumor foci in an individual patient was not predictive. CONCLUSIONS: TACE appears to result in improved survival among HCC patients with hypervascular tumors who responded to therapy. However, even patients classified by CT as hypervascular nonresponders and hypovascular responders have improved survival.

Adult↗
PubMed2003

Complications of liver transplantation: imaging and intervention.

The radiologist can play a key role in diagnosis and management of many of the infectious, inflammatory, and neoplastic processes that affect patients after liver transplantation. Familiarity and skill with the full range of diagnostic and interventional tools are essential for radiologists dealing with transplant patients, even outside the medical centers where the transplantation takes place.

Diagnosis, Differential↗
PubMed2003

Evaluation of optimal timing of arterial phase imaging for the detection of hypervascular hepatocellular carcinoma by using triple arterial phase imaging with multidetector-row helical computed tomography.

PURPOSE: We evaluated the optimal timing of arterial phase imaging for detection of hypervascular hepatocellular carcinoma by using triple arterial phase imaging with multidetector-row helical computed tomography. MATERIALS AND METHODS: Forty-nine patients with 90 hypervascular hepatocellular carcinomas (3 to 50 mm in diameter; mean, 18.7 mm) underwent triple arterial phase imaging of the whole liver using a multidetector-row helical computed tomography. At 20 seconds, 30 seconds, and 40 seconds after intravenous administration of 100 mL of 300 mgI/mL of nonionic contrast medium at a rate of 4 mL/s, early, middle, and late arterial phase images were obtained serially during a single breath-hold with an interscan delay of 5 seconds. Detector-row configurations of 4 mm x 4, scan pitch of 5.5, and scan time of 5 seconds for each phase were used. Forty prospective reconstruction images of 5-mm thickness for each phase were obtained. The images from each phase were interpreted separately for detection of hypervascular hepatocellular carcinoma by 3 observers independently who were unaware of tumor burden in the liver. Sensitivity, positive predictive value, and area under the receiver operating characteristic curve values for each arterial phase were calculated and compared statistically. RESULTS: The mean sensitivity and positive predictive values for hypervascular hepatocellular carcinoma diagnosis of blind readers were 37% and 87% for the early arterial phase, 73% and 85% for the middle arterial phase, and 49% and 81% for the late arterial phase, respectively. The middle arterial phase imaging showed significantly superior sensitivity compared with the early and late arterial phase for detecting hepatocellular carcinoma (P < 0.05). Mean area under the receiver operating characteristic curve value of the middle arterial phase imaging (0.84) was significantly higher that that of the early (0.56) or late arterial phase (0.62; P < 0.05). CONCLUSION: If a single arterial phase is used for diagnosis of hypervascular hepatocellular carcinoma, the middle phase (delay time of 30 seconds) is optimal.

Adult↗
PubMed2003

Multidetector CT arteriography with volumetric three-dimensional rendering to evaluate patients with metastatic colorectal disease for placement of a floxuridine infusion pump.

OBJECTIVE: We sought to evaluate the usefulness of multidetector CT (MDCT) arteriography with volumetric three-dimensional (3D) rendering to depict the hepatic vascular anatomy. Our study population was patients who had undergone arterial mapping in preparation for placement of a hepatic arterial floxuridine infusion pump for treatment of metastatic hepatic colorectal carcinoma. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 26 patients with hepatic colorectal metastases who had been scheduled for implantation of a hepatic artery pump. Before surgery, all patients underwent MDCT arteriography with volumetric 3D rendering of the hepatic vessels. The axial and 3D arteriograms were evaluated for their usefulness in depicting hepatic arterial anatomy. Subsequently, three patients also underwent catheter angiography. Twenty-two of the 26 patients imaged had a hepatic artery floxuridine infusion pump implanted. Results of the CT arteriography were correlated with findings at surgery or on catheter angiography if surgery was not performed. RESULTS: MDCT arteriography correctly revealed hepatic arterial anatomy in all 25 patients with angiographic or surgical confirmation. One patient with aberrant hepatic arterial anatomy did not have angiographic or surgical confirmation. Classic hepatic arterial anatomy was identified in 16 (64%) of 25 patients. The following hepatic arterial variants were found in one patient each: the common hepatic artery arising directly from the aorta; a replaced left hepatic artery; an accessory right hepatic artery; a replaced left hepatic artery and accessory right hepatic artery; a replaced right hepatic artery; a right hepatic arterial branch arising early (before the origin of the gastroduodenal artery); and replaced right and left hepatic arteries. Three patients were not suitable candidates for placement of a hepatic artery floxuridine pump. The patient who had no angiographic or surgical confirmation was also not considered a good surgical candidate because of replaced right and left hepatic arteries. Two patients (8%) had an accessory left hepatic artery. CONCLUSION: MDCT arteriography with volumetric 3D rendering is an accurate, noninvasive method of depicting hepatic arterial anatomy and, therefore, of selecting patients with colorectal metastatic disease who could benefit from hepatic artery pump implantation. Catheter angiography provides no additional information, and we have eliminated it as a routine preoperative imaging examination.

Aged↗