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Biomedical subjects

R L Baron

Publications and source records attributed to R L Baron.

At least 37 records · Page 2Linked to original sources
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

Bile duct calculi in patients with primary sclerosing cholangitis.

PURPOSE: To determine the imaging appearance and frequency of detection of bile duct calculi in patients with primary sclerosing cholangitis. MATERIALS AND METHODS: Images (169 computed tomographic [CT] scans, 155 sonograms, and 109 cholangiograms) of 189 patients with primary sclerosing cholangitis, five of whom were prospectively included, were reviewed. Pathologic records were reviewed for proof of the presence of calculi. RESULTS: Bile duct calculi were visualized on images in 14 (7.6%) of the 184 retrospective patients and in all five of the prospective patients. The presence of calculi was confirmed with pathologic or imaging findings in 19 patients, in whom calculi were visible on 16 of 18 CT scans, 15 of 19 sonograms, and 14 of 17 cholangiograms. Calculi were in the intrahepatic ducts in 11 patients and in the intra- and extrahepatic bile ducts in eight patients. At CT, calculi appeared as foci of faint high attenuation or as coarse calcifications in nondilated or variably dilated ducts. At sonography, they appeared as unique echogenic casts with variable posterior acoustic shadowing or as discrete, echogenic, variably shadowing foci in variably dilated ducts. Calculi were depicted at cholangiography as rounded filling defects. CONCLUSION: Intrahepatic bile duct calculi are present in approximately 8% of patients and can have a unique imaging appearance.

Adult↗
PubMed1997

Hepatocellular carcinoma: the role of helical biphasic contrast-enhanced CT versus CT during arterial portography.

PURPOSE: To assess the role of helical biphasic computed tomography (CT) versus CT during arterial portography (CTAP) in the detection of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Helical biphasic CT and CTAP examinations were performed in 33 patients with biopsy-proved HCC. Three blinded radiologists retrospectively evaluated portal venous phase images, portal venous phase plus hepatic arterial phase images (helical biphasic CT), and CTAP plus portal venous phase images at separate sittings. In 23 patients with pathologic proof of total tumor burden, the readers conducted a consensus matched-pair reading to determine the sensitivity of each method. RESULTS: In the 23 patients with a proved tumor burden of 100 HCC lesions, the observers detected 74 tumors on portal venous phase images, 82 tumors on hepatic arterial phase images, 87 tumors on CTAP images, 87 tumors on helical biphasic CT images, and 96 tumors on portal venous phase plus CTAP images. Hepatic arterial phase images and CTAP images, respectively, depicted 13 and 23 tumors not seen on portal venous phase images in eight (35%) and 13 (56%) of 23 patients. Ten tumors were seen on portal venous phase images but not on CTAP images owing to the presence of central tumors or segmental portal venous thrombi that obstructed the flow of contrast material to more peripheral portions of the liver. CONCLUSION: The addition of hepatic arterial phase imaging to portal venous phase imaging (helical biphasic CT) provided an incrementally increased yield in HCC tumor detection. Helical biphasic CT should be used as the initial screening examination in patients with suspected or known HCC.

Adult↗
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↗
PubMed1997

Benign and malignant portal vein thrombosis: differentiation by CT characteristics.

OBJECTIVE: The purpose of this study was to determine if unique characteristics revealed by CT can allow radiologists to reliably distinguish benign from malignant portal vein thrombus (PVT) in patients with cirrhosis. MATERIALS AND METHODS: CT examinations of 58 patients with cirrhosis and PVT were retrospectively reviewed. Images were assessed for location, extent, enhancement, neovascularity, and maximal diameter of PVT. The type of PVT was proven histologically in 42 patients and clinically in the remaining 16 patients. Using different threshold PVT diameters or the presence of PVT neovascularity, we calculated the sensitivity and specificity of CT for revealing malignant PVT. RESULTS: Forty-seven patients had malignant and 11 patients had benign PVT. CT scans of patients with malignant PVT showed direct extension of hepatocellular carcinoma into the portal vein in 15 patients. In 29 patients with malignant PVT, CT scans showed PVT adjacent to tumor; CT scans showed tumor PVT remote from hepatocellular carcinoma in the remaining three patients with malignant PVT. The mean diameters of malignant and benign portal vein thrombi were significantly different (23.4 mm versus 16 mm; p = .0001). CT scans of 83% (39/47) of patients with malignant PVT and 18% (2/11) of patients with benign PVT showed generalized enhancement. Neovascularity was seen on CT scans in 43% (20/47) of patients with malignant PVT and in no patient with benign PVT. Identification of a main PVT diameter greater than or equal to 23 mm or PVT neovascularity resulted in a sensitivity and specificity for the CT characterization of malignant PVT of 86% and 100%, respectively. CONCLUSION: Malignant and benign thrombi can often be differentiated by radiologists on the basis of CT imaging characteristics.

Carcinoma, Hepatocellular↗
PubMed1997

Imaging of digital neuromas.

In this case presentation, an incision was made on the nonweightbearing surface of the hallux directly over the mass in question, just long enough to allow for the isolation of the entire mass. This permitted easier identification of the mass and enabled dissection of the abnormal tissue and excision of only the tumor with a minimum of tissue trauma. Healing was uneventful and expedient largely because of the reduced tissue handling. Prior to the advent of magnetic resonance imaging, this type of preoperative detailed surgical mapping would not have been possible. Continuing improvements in magnetic resonance imaging hold great and increasing promise.

Adult↗
PubMed1996

Sonography: the undiscovered jewel of interventional radiology.

Because most radiologists in the United States have been taught that fluoroscopy and computed tomography (CT) are the best guidance techniques for nonvascular interventional procedures, sonography has been greatly underused in this regard. Recently, sonography has been gaining recognition as a highly useful and versatile guidance technique. It has many advantages over CT and fluoroscopic guidance, including real-time imaging with vessel visualization, decreased procedure time and cost, portability, and lack of ionizing radiation. Sonography should be the primary guidance technique for many nonvascular interventional procedures, and use of sonography as an adjunct guidance technique increases the ease and speed with which many other interventional procedures are performed. Sonography should generally be used instead of CT for guidance of abdominal and pelvic biopsy and drainage. Sonographic guidance should replace CT and fluoroscopic guidance for biopsy and drainage of accessible peripheral thoracic and mediastinal masses. Use of sonographic guidance should be integrated into all interventional radiology suites to reduce radiation exposure and facilitate the performance of many nonvascular and some vascular interventional procedures that have traditionally been performed under fluoroscopic guidance.

Biopsy, Needle↗
PubMed1996

Recurrent hepatocellular carcinoma after liver transplantation: spectrum of CT findings and recurrence patterns.

PURPOSE: To correlate computed tomographic (CT) and serum tumor marker (alpha-fetoprotein [AFP] and des-gamma-carboxy-prothrombin [DGCP]) findings in recurrent hepatocellular carcinoma (HCC) after orthotopic liver transplantation (OLT). MATERIALS AND METHODS: At retrospective review of the cases in 124 patients, CT findings were recorded by consensus of at least two nonblinded observers and compared with levels of AFP and DGCP. RESULTS: In 35 patients (68 sites), CT depicted recurrent HCC (most frequently in lungs [n = 18] and liver allograft [n = 16]) in a single site in 19 patients (54%) and in more than one site in 16 patients (46%). No stage I or II HCC recurred after 18-78 months (mean recurrence, 39 months). Stage IVA HCC recurred four times as often as stage III HCC (P < .001). Abnormally high serum AFP and DGCP levels indicated 69% and 43%, respectively, in patients with recurrent disease. CONCLUSION: HCC recurrence after OLT correlates with initial stage, and CT is more sensitive than serum tumor markers in its detection.

Adult↗
PubMed1996

Liver necrosis and regeneration after fulminant hepatitis: pathologic correlation with CT and MR findings.

PURPOSE: To characterize computed tomographic (CT) and magnetic resonance (MR) findings of liver necrosis and regeneration after fulminant hepatitis. MATERIALS AND METHODS: Three patients with fulminant hepatitis underwent CT before orthotopic liver transplantation; one also underwent MR imaging. These findings were retrospectively reviewed and compared with gross and histologic findings obtained after transplantation. RESULTS: Regions of liver necrosis demonstrated low attenuation on CT scans before contrast material was administered and enhanced to attenuation equal to or greater than that of liver regeneration on postcontrast CT images. Conversely, nodular liver regeneration demonstrated hyperattenuation on precontrast and hypoattenuation on postcontrast CT images, which simulated neoplastic lesions. The necrotic liver parenchyma was seen as high and low intensity on T2- and T1-weighted MR images, respectively, whereas areas of regeneration appeared as hypo- and hyperintense. CONCLUSION: Characteristic patterns of liver regeneration after fulminant hepatitis may be seen at CT and MR imaging. Recognition of this regeneration process may avoid an incorrect diagnosis of malignancy.

Acute Disease↗
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

Image-guided percutaneous hepatic biopsy: effect of ascites on the complication rate.

PURPOSE: To determine if image-guided percutaneous hepatic biopsy is contraindicated in patients with ascites. MATERIALS AND METHODS: The records of 476 patients (173 with ascites and 303 without) who underwent image-guided hepatic biopsy were reviewed retrospectively for number of passes, type of needle, and indications. Coagulopathy was corrected with appropriate blood products before biopsy. Complications were classified as minor (decrease in hematocrit value not necessitating treatment) of major (bleeding that necessitated transfusion or surgery or resulted in death). RESULTS: Major complications occurred in six patients with ascites and 10 without. Minor complications occurred in 10 patients with ascites and 15 without. With ascites, all major complications necessitated blood transfusions but not surgery. Five patients with major complications had a documented moderate or severe amount of perihepatic ascites. without ascites, nine of the 10 patients required blood transfusions and one required surgery. No deaths occurred in either group. CONCLUSION: Perihepatic ascites does not statistically significantly affect the major of minor complication rate of image-guided percutaneous hepatic biopsy.

Ascites↗
PubMed1996

Hepatocellular carcinoma: evaluation with biphasic, contrast-enhanced, helical CT.

PURPOSE: To evaluate the added value of hepatic arterial-dominant phase (HAP) imaging to portal venous-dominant phase (PVP) imaging in patients with hepatocellular carcinoma (HCC) at computed tomography (CT). MATERIALS AND METHODS: Sixty-six patients with proved HCC underwent biphasic contrast-enhanced CT. HAP and PVP images were obtained at 20-50 and 60-100 seconds, respectively. PVP images were evaluated for the number of HCC foci. Then, HAP images were reviewed to determine whether any additional HCCs were seen. RESULTS: Three hundred twenty-six tumor foci were seen. HAP images depicted 309 foci (95%) and PVP images 268 (82%). In seven patients (11%), tumor was visible only on HAP images. During the HAP, tumors were hyperattenuating compared with liver in 26 patients, of mixed attenuation in 26, and hypoattenuating in 14 without correlation with histologic appearance. Portal vein thrombosis was identified in 17 of 21 patients on HAP images; in 12 patients, the thrombosis was diagnosed as malignant with neovascularity within the thrombus or diffuse thrombus enhancement. CONCLUSION: Use of both HAP and PVP contrast-enhanced CT optimizes the evaluation of patients with or at risk for HCC.

Carcinoma, Hepatocellular↗
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

Hepatic malignancies: usefulness of acquisition of multiple arterial and portal venous phase images at dynamic gadolinium-enhanced MR imaging.

PURPOSE: To determine whether liver tumor detection is increased by acquiring multiple dynamic arterial phase and portal venous phase magnetic resonance (MR) images. MATERIALS AND METHODS: Dynamic MR imaging was performed in 205 patients at 1.5 T with use of a fast spoiled gradient-echo technique (repetition time, 9-12 msec; echo time, 2.1-3.0 msec; flip angle, 30 degrees). During intravenous bolus injection of gadopentetate dimeglumine or gadoteridol (0.1 mmol/kg), nine images were acquired at each of 10-12 locations over approximately 120 seconds. The number of tumors detected on arterial phase and portal venous phase images and unenhanced T1- and T2-weighted spin-echo (SE) images was evaluated separately. Data obtained in 75 patients with proved malignancies were analyzed. RESULTS: At imaging, 220 malignant tumor nodules were depicted. At prospective review of all images, 110 hepatocellular carcinomas (HCCs) were detected: 82 (75%) on unenhanced T1-weighted SE images, 83 (75%) on unenhanced T2-weighted SE images, 92 (84%) on arterial phase images, and 76 (69%) on portal venous phase images. At prospective review, eight HCCs were detected on only arterial phase images, one on only portal venous phase images, nine on both arterial and portal venous phase images, and 11 on only unenhanced SE images. The 18 additional HCCS detected prospectively on only dynamic images increased HCC detection by 21% over prospective detection on only SE images. Detection of non-HCC tumors (including metastases) did not increase with dynamic images. CONCLUSION: Acquisition of multiple dynamic arterial phase and portal venous phase images increased detection of HCC but not metastases.

Adult↗
PubMed1996

Hepatic infarction caused by arterial insufficiency: spectrum and evolution of CT findings.

PURPOSE: To determine the CT imaging appearances of liver infarction due to arterial insufficiency and to attempt to understand reasons for apparent discrepancy of appearance in prior reports. MATERIALS AND METHODS: Thirty-seven CT examinations from 18 patients with proven hepatic infarction were evaluated for character, location, and evolution of lesions by all investigators, with a consensus interpretation. Etiologies of infarction included posttransplant complication (15), laparoscopic cholecystectomy complication (2), and traumatic arterial injury (1). Proof of hepatic infarction was made by hepatectomy (11), biopsy (1), or clinical course compatible with infarction with angiographic (3) or surgical (3) evidence of hepatic arterial abnormality. In patients without histologic proof of infarction, all lesions seen at CT were considered to be due to hepatic infarction, except those meeting the criteria for hemangioma. In 10 patients, serial examinations were available over 2-180 days and a determination of serial changes in specific lesions was made using a similar image analysis. RESULTS: Of 55 lesions identified, 53 could be classified into three shapes--wedge-shaped (18), rounded or oval (26), or irregularly shaped low-attenuation lesions paralleling bile ducts (9). The other two lesions were flat hypodense areas along the posterior aspect of the medial left hepatic lobe. Wedge-shaped lesions were peripherally located; rounded lesions were either peripheral (10) or central (26). The caudate lobe was spared except in one patient. Of 16 serially followed wedge-shaped lesions, four evolved into rounded lesions. No rounded lesions became wedge-shaped. CONCLUSION: Hepatic infarction caused by arterial disease produces a spectrum of CT findings. Prior reported discrepancies in appearance may be due to the small number of cases in each report and the variety of potential imaging appearances,aas well as evolutionary changes.

Adult↗