Multiphasic Computed Tomography Research Articles

Hepatocellular carcinoma in noncirrhotic liver: CT, clinical, and pathologic findings in 39 U.S. residents.

To review clinical, pathologic, and computed tomographic (CT) findings in patients with hepatocellular carcinoma (HCC) in noncirrhotic liver. Clinical, pathologic, and imaging findings were retrospectively evaluated in 39 patients with HCC in noncirrhotic liver. Helical multiphasic CT scans obtained with 125 mL of contrast medium at a rate of 4 or 5 mL/sec were reviewed for morphologic features such as tumor size, margins, and hemorrhage and degree of enhancement. All patients (25 men, 14 women; mean age, 61 years) were U.S. residents; none had an Asian surname. Twenty-four patients (62%) had no identifiable risk factors; 34 (87%) were symptomatic. HCC was proved and cirrhosis excluded with biopsy in all cases. HCC was moderately (n = 32) or well (n = 6) differentiated in 97% of cases and poorly differentiated in one. Serum alpha-fetoprotein level was elevated in 26 patients. Large tumors (mean diameter, 12.4 cm) were depicted at CT in all cases. Thirty-two patients had a solitary or dominant mass. At CT, tumor margins were well defined in 21 patients, with a lobulated surface in 33. Calcifications were depicted in 11, hemorrhage in 10, fat in four, dilated intrahepatic bile ducts in 17, and abdominal lymphadenopathy in eight. In 38 patients, tumors were heterogeneous with areas of necrosis. HCC was hypoattenuating on nonenhanced images in 34, heterogeneously hyperattenuating at arterial phase in 38, and hypoattenuating at portal phase in 35 patients. HCC developed in the absence of cirrhosis or known risk factors and typically appeared as a large symptomatic hepatic tumor with clinical, laboratory, and CT features that distinguish it from most other hepatic masses.

Hepatocellular carcinoma: correlation between vascular endothelial growth factor level and degree of enhancement by multiphase contrast-enhanced computed tomography.

To determine whether vascular endothelial growth factor (VEGF) is a histopathological factor influencing contrast enhancement of hepatocellular carcinoma (HCC) on computed tomography (CT). Twenty-two nodular HCCs underwent multiphase helical CT and surgery. Tumor size, histological grading of differentiation, and type of hepatitis were evaluated. Tumor attenuation was graded as hyperattenuated, isoattenuated, and hypoattenuated. Immunohistochemical staining with anti-VEGF antibody was performed and scored as weak, intermediate, or strong. Spearman's rank correlation test was used. Tumors ranged from 1.0 to 12.0 cm (mean 5.1 cm). The degree of enhancement during the hepatic arterial phase was significantly correlated with VEGF expression. Size was negatively correlated with VEGF expression and the degree of enhancement, but histological grade and type of hepatitis were not correlated with VEGF expression, tumor size, or degree of enhancement. In HCC, VEGF expression is correlated with the degree of contrast enhancement during arterial-phase CT.

Primary biliary cirrhosis: clinical, pathologic, and helical CT findings in 53 patients.

To evaluate and compare clinical, pathologic, and helical computed tomographic (CT) findings of primary biliary cirrhosis (PBC). The authors reviewed the medical records and CT scans of 53 patients who underwent evaluation, treatment, and orthotopic liver transplantation (OLT) at their institution. All patients underwent helical multiphase CT (total, 98 abdominal CT scans; range, one to five scans per patient). Multiple epidemiologic, clinical, and morphologic criteria were evaluated. Advanced disease was defined as hepatic insufficiency leading to OLT within the subsequent 2 years. Clinical and morphologic features were evaluated and compared in the advanced and less advanced cases of PBC. Common and characteristic findings included the following: 45 (85%) of the 53 patients were women with the onset of disease (diagnosis) in middle age (mean, 50.7 years; range, 26-71 years). The average time from diagnosis to OLT was 6.1 years (range, 1.5-20.0 years). CT findings in advanced PBC often resembled those seen in other forms of cirrhosis, with a small heterogeneously attenuating liver, varices, and splenomegaly. The liver in less advanced disease was usually enlarged or normal in size, with a smooth contour, little atrophy, and lacelike fibrosis and regenerative nodules in nearly one-third of the livers. Patients with less advanced disease frequently had varices (n = 33 [62%]) and ascites (n = 13 [24%]). Lymphadenopathy was seen in 47 (88%) patients. Hepatocellular carcinoma was found in four (8%) patients, two of whom also had chronic hepatitis C. During a follow-up period of 5-72 months (median, 46 months; mean, 42 months) after OLT, only two patients experienced recurrence of PBC. PBC is an important cause of liver failure, with distinctive clinical and CT findings that may assist diagnosis and allow adequate treatment. CT can demonstrate varices and ascites before frank cirrhosis is evident and can help evaluate the progression of the disease.

Hepatic adenomas: imaging and pathologic findings.

Hepatocellular adenoma is a rare benign lesion that is most often seen in young women with a history of oral contraceptive use. It is typically solitary, although multiple lesions have been reported, particularly in patients with glycogen storage disease and liver adenomatosis. Because of the risk of hemorrhage and malignant transformation, hepatocellular adenomas must be identified and treated promptly. At pathologic analysis, hepatocellular adenoma is usually a well-circumscribed, nonlobulated lesion, and at gross examination, resected adenomas frequently demonstrate areas of hemorrhage and infarction. Most adenomas are not specifically diagnosed at ultrasonography (US) and are usually further evaluated with computed tomography (CT) or other imaging modalities. Color Doppler US may help differentiate hepatocellular adenoma from focal nodular hyperplasia. Multiphasic helical CT allows more accurate detection and characterization of focal hepatic lesions. Hepatocellular adenomas are typically bright on T1-weighted magnetic resonance images and predominantly hyperintense relative to liver on T2-weighted images. The prognosis of hepatic adenoma is not well established. Criteria that guide treatment include the number and size of the lesions, the presence of symptoms, and the surgical risk incurred by the patient. Understanding the imaging appearance of hepatocellular adenoma can help avoid misdiagnosis and facilitate prompt, effective treatment.

Focal Nodular Hyperplasia: CT Findings with Emphasis on Multiphasic Helical CT in 78 Patients

To evaluate features of focal nodular hyperplasia (FNH) at multiphasic helical computed tomography (CT). Clinical, pathologic, and preoperative imaging findings were retrospectively reviewed in 78 patients. Conventional liver CT was performed in nine patients; helical multiphasic CT, in 69. Diagnosis was based on complete resection (n = 20), biopsy (n = 42), or clinical and imaging follow-up for a minimum of 6 months (n = 16). Number, size, location, margins, surface, homogeneity of enhancement, and presence of a central scar, mass effect, exophytic growth, calcification, pseudocapsule, or vessels feeding or draining the lesion were evaluated. CT depicted 124 tumors (mean diameter, 4.1 cm; range, 1-11 cm); 62 were small (< or =3 cm). FNHs were hypervascular and hyperattenuating to liver on 106 of 106 arterial phase scans and were isoattenuating to liver on 82 of 89 delayed scans. Of the 124 tumors, 111 enhanced homogeneously, 109 had a smooth surface, 101 were subcapsular, 89 had ill-defined margins, and 62 had a central scar that was observed more often in large lesions (40 of 62 lesions) than in small lesions (22 of 62 lesions). FNHs less frequently exerted a mass effect (43 lesions), had vessels around or within the lesion (42 lesions), demonstrated exophytic growth (40 lesions), or showed a pseudocapsule (10 lesions). Only one FNH had calcification. Helical CT demonstrates characteristic features that may allow confident diagnosis of FNH. In typical cases, neither biopsy nor further imaging is necessary.

Imaging for right lobe living donor liver transplantation.

The authors describe their experience using multidetector, multiphase computed tomography (CT) for the preoperative evaluation of donors undergoing adult right lobe liver transplantation. The marked improvement in image resolution has been extremely valuable in delineating small hepatic arterial structures, including accessory and replaced vessels. Assessment of liver parenchyma is valuable in determining the presence of steatosis or other unexpected abnormalities. Measurement of total liver volume is highly accurate and reproducible. Virtual hepatectomy can be performed in an avascular plane between the right and left lobes, to the right of the middle hepatic vein. Knowledge of the resultant right and left lobe volumes is critical in patient selection. Multidetector, multiphase CT, as a single imaging modality, provides a minimally invasive comprehensive pre-operative evaluation that can be expected to have a major impact on patient selection and surgical planning.

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

To evaluate multiphasic computed tomographic (CT) findings of hepatic adenomas and to correlate these findings with those of histopathologic analysis. 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. 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). Hepatic adenomas often have characteristic features at multiphasic CT that may allow their distinction from other hepatic masses.

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

To review characteristic findings of fibrolamellar hepatocellular carcinoma (HCC) at computed tomography (CT) and magnetic resonance (MR) imaging. 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. 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. CT and MR images demonstrate characteristic features that may allow confident diagnosis of fibrolamellar HCC.

Liver metastases from melanoma: detection with multiphasic contrast-enhanced CT.

To assess the clinical utility of multiphasic computed tomography (CT) of the liver in patients with metastatic melanoma. Nonenhanced and biphasic hepatic CT examinations were performed in 28 patients with metastatic melanoma, and liver lesion conspicuity was graded. CT studies in 20 patients met the eligibility criteria, and 13 patients had liver lesions. A total of 57 liver lesions were seen on CT studies: 48 on hepatic arterial phase images, 49 on portal venous phase phase images, and 30 on delayed phase images. Of eight lesions overlooked on portal venous phase images, six were seen on nonenhanced images, and six were seen on arterial phase images. Twenty-eight lesions were graded as more conspicuous on portal venous phase images; 10 were graded as more conspicuous on arterial phase images. CT images obtained only during the portal venous phase would have resulted in eight (14%) overlooked lesions, which implies that more than one phase is needed for hepatic CT in patients with malignant melanoma. The combination of nonenhanced and portal venous phase CT was as effective as the combination of arterial and portal venous phase CT in these patients. Delayed phase CT did not improve lesion detection either alone or in combination with CT at other phases.

Multiphasic helical CT of the kidney: increased conspicuity for detection and characterization of small (< 3-cm) renal masses.

To evaluate the potential of thin-section multiphasic helical computed tomography (CT) in the detection and characterization of small (< 3.0-cm) renal masses. Identically collimated helical CT of the kidney was performed before and after administration of contrast material in 93 patients with small renal masses. Helical CT scans were obtained during the corticomedullary and nephrographic phases. Differences between attenuation of the lesion and that of the kidney were measured quantitatively. The presence of a mass or absence of disease was confirmed with clinical, imaging, and histologic findings. The number of masses smaller than 3.0 cm detected on corticomedullary-phase scans (n = 211) was statistically significantly fewer than those on nephrographic-phase scans (n = 295) (P < .01). Mean differences in enhancement between the renal cortex and masses were 148 HU +/- 54 and 137 HU +/- 44 during the corticomedullary and nephrographic phases, respectively, and the difference in attenuation of the renal medulla and that of the masses was statistically significantly greater during the nephrographic phase (P < .01). False-positive results (n = 9) occurred only on corticomedullary-phase scans because of lack of enhancement of the renal medulla. Nephrographic-phase scans enabled greater lesion detection and better characterization of small renal masses than corticomedullary-phase scans. Nephrographic-phase scans should be obtained when only monophasic scanning is used to detect small renal masses.

Multiphasic renal CT: comparison of renal mass enhancement during the corticomedullary and nephrographic phases.

To evaluate thin-section computed tomography (CT) performed during the corticomedullary and nephrographic phases of contrast material enhancement in the characterization of renal masses. A prospective study of 30 patients was undertaken with CT to characterize 31 "indeterminate" renal masses. In all patients, 5-mm-thick, contiguous, high-tube-current (320-340-mA) scans were obtained through the kidneys before (axial mode), during (helical mode, 25-second delay, corticomedullary-phase images), and after (axial mode, 120-second delay, nephrographic-phase images) administration of a 117-second biphasic injection of intravenous contrast material. Eight of 16 neoplasms measured less than 20 HU on CT scans obtained without contrast material enhancement; measurements of two of these corresponded to "cyst attenuation" during the corticomedullary phase. Enhancement of 10 HU or greater was demonstrated in 11 neoplasms during the corticomedullary phase and in all neoplasms in the nephrographic phase. No enhancement was seen in 15 radiologically benign cysts. Both renal neoplasms and normal renal cortex demonstrated significantly greater enhancement in the nephrographic phase compared with that in the corticomedullary phase (P = .0002 and P < .0001, respectively). Enhancement of renal neoplasms is time dependent and may not be evident in hypovascular tumors analyzed during the early corticomedullary phase. Reliance on absolute CT attenuation measurements, without use of internal standards as controls, may lead to misdiagnosis of neoplasms as cysts.