Multiphasic Computed Tomography Research Articles

Chemotherapy-induced sclerosing cholangitis

To review the computed tomography (CT), magnetic resonance imaging (MRI) and cholangiographic findings of chemotherapy-induced sclerosing cholangitis (CISC). Between January 1995 and December 2004, 11 patients in the endoscopic retrograde cholangiography database were identified with CISC. Twelve CT, four MRI, 69 endoscopic and nine antegrade cholangiographic studies in these patients were reviewed. Serial change in appearance and response to endoscopic treatment were recorded. CISC showed segmental irregular biliary dilatation with strictures of proximal extrahepatic bile ducts. The distal 5cm of common bile duct was not affected in any patient. CT and MRI findings included altered vascular perfusion of one or more liver segments, liver metastases or peritoneal carcinomatosis. Biliary strictures needed repeated stenting in 10 patients (mean: every 4.7 months). Cirrhosis (n=1) or confluent fibrosis (n=0) were uncommon findings. CISC shares similar cholangiographic appearances to primary sclerosing cholangitis (PSC). Unlike PSC, biliary disease primarily involved ducts at the hepatic porta rather than intrahepatic ducts. Multiphasic contrast-enhanced CT or MRI may show evidence of perfusion abnormalities, cavitary liver lesions, or metastatic disease.

Computed Tomography Features of an Intraductal Polypoid Mass

To determine the computed tomography (CT) features capable of differentiating hepatocellular carcinoma (HCC) with bile duct tumor invasion (BDTI) from intraductal cholangiocarcinoma (IDCC). Multiphasic CT images of 14 patients with HCC with BDTI and 18 patients with IDCC were retrospectively reviewed. Analysis of the CT findings included the size, location, and margin of the intraductal mass; enhancement pattern of intraductal lesions; degree of ductal dilatation; presence of downstream ductal dilatation and ductal wall thickening; presence of a parenchymal mass and its size; continuity of the parenchymal mass with the intraductal mass; and liver cirrhosis. Objective evaluation of the enhancement patterns of intraductal tumors was done by measuring the CT attenuation coefficients of the tumors and the uninvolved hepatic parenchyma in each phase. Among these findings, statistically significant variables were then determined using the Fisher's exact test or Mann-Whitney U test. Significant variables that helped to differentiate HCC with BDTI from IDCC included the presence of a parenchymal mass, liver cirrhosis, and a hyperattenuating intraductal tumor on the hepatic arterial phase (HAP). On unenhanced images, the tumor-to-liver contrast of IDCC (16.7+/-8.1) was greater than that of HCC with BDTI (6.4+/-10.4), but on the HAP, that of HCC with BDTI (26.5+/-28.2) was greater than that of IDCC (5.9+/-18.7) (P<0.05). In addition, there was a significant difference in the enhancement ratio of the intraductal tumors on the portal venous phase between the 2 conditions (P=0.003). Several objective and subjective multiphasic CT findings may help to differentiate HCC with BDTI from IDCC.

Hepatocellular Carcinoma in Patients with Chronic Liver Disease: Comparison of SPIO-enhanced MR Imaging and 16–Detector Row CT

To compare the sensitivity, positive predictive value, and diagnostic accuracy of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging with those of 16-detector row computed tomography (CT) for the detection of hepatocellular carcinoma (HCC) in patients with hepatitis B-induced cirrhosis. Institutional Review Board approval was obtained for this study, and informed consent was obtained from all patients. A total of 44 patients (36 men, eight women; age range, 35-67 years) with 59 HCCs and mild liver cirrhosis (Child-Pugh score A or B) underwent multiphasic CT and SPIO-enhanced MR imaging. The diagnosis of HCC was established at surgical resection (n = 31) and percutaneous biopsy (n = 28). SPIO-enhanced MR imaging was composed of T2-weighted turbo spin-echo and T2*-weighted gradient-echo sequences. Multiphasic CT consisted of four phases (ie, early arterial, late arterial, portal venous, and equilibrium). Three observers independently analyzed each image in random order. Sensitivity, positive predictive value, and diagnostic accuracy were calculated by using the alternative free-response receiver operating characteristic analysis for multi-detector row CT and SPIO-enhanced MR imaging. Although not significant (P > .05), the area under the receiver operating characteristic curve for SPIO-enhanced MR imaging (mean, 0.90) was higher than that for multi-detector row CT (mean, 0.82) for all observers. Also, although no significant difference was demonstrated by any of the three observers (P > .05), there was a trend toward increased sensitivity on both a per-lesion and a per-patient basis for SPIO-enhanced MR imaging (mean, 84.7% and 94.7%, respectively) compared with multi-detector row CT (mean, 76.9% and 88.6%, respectively). No significant difference in positive predictive value was observed between modalities. SPIO-enhanced MR imaging and multiphasic CT show similar diagnostic accuracy, sensitivity, and positive predictive value for the detection of HCC in patients with relatively mild hepatitis B-induced cirrhosis.

Imaging Features of Perivascular Fatty Infiltration of the Liver: Initial Observations

To retrospectively identify and describe the imaging features that represent perivascular fatty infiltration of the liver. The institutional review board approved the study and waived informed consent. The study complied with the Health Insurance Portability and Accountability Act. Ten patients (seven women, three men; mean age, 78 years; range, 31-78 years) with fatty infiltration surrounding hepatic veins and/or portal tracts were retrospectively identified by searching the abdominal imaging teaching file of an academic hospital. The patients' medical records were reviewed by one author. Computed tomographic (CT), magnetic resonance (MR), and ultrasonographic (US) imaging studies were reviewed by three radiologists in consensus. Fatty infiltration of the liver on CT images was defined as absolute attenuation less than 40 HU without mass effect and, if unenhanced images were available, as relative attenuation at least 10 HU less than that of the spleen; on gradient-echo MR images, it was defined as signal loss on opposed-phase images compared with in-phase images; and on US images, it was defined as hyperechogenicity of liver relative to kidney, ultrasound beam attenuation, and poor visualization of intrahepatic structures. Perivascular fatty infiltration of the liver was defined as a clear predisposition to fat accumulation around hepatic veins and/or portal tracts. For multiphase CT images, the contrast-to-noise ratio was calculated for comparison of spared liver with fatty liver in each imaging phase. Fatty infiltration surrounded hepatic veins in three, portal tracts in five, and both hepatic veins and portal tracts in two patients. Six of the 10 patients had alcoholic cirrhosis, two reported regular alcohol consumption (one of whom had acquired immunodeficiency syndrome and hepatitis B), one was positive for human immunodeficiency virus, and one had no risk factors for fatty infiltration of the liver. In three of the 10 patients, fatty infiltration was misdiagnosed as vascular or neoplastic disease on initial CT images but was correctly diagnosed on MR images. Perivascular fatty infiltration of the liver has imaging features that allow its recognition.

Multiphasic CT and MRI appearances of extramedullary multiple myeloma involving the stomach, pancreas, and bladder

Multiple myeloma is a hematological malignancy characterized by the uncontrolled proliferation of clonal plasma cells. Skeletal involvement is one of its hallmarks, while extraosseous involvement is comparatively uncommon. There have been no previous reports of the imaging findings of multiple myeloma involving the stomach, pancreas, and bladder in the same patient. The stomach and pancreatic lesions were demonstrated as hypervascular nodules on computed tomography (CT), more conspicuous on arterial phase images. Early phase post-contrast imaging might improve the detection of extraosseous myeloma.

Differentiating Malignant from Benign Common Bile Duct Stricture with Multiphasic Helical CT

To evaluate retrospectively the use of multiphasic helical computed tomography (CT) to differentiate malignant and benign common bile duct (CBD) strictures in patients with only a focal CBD stricture and to determine predictors for this differentiation. Institutional review board approval and informed patient consent were not required. Fifty patients (35 men, 15 women; age range, 35-87 years; mean age, 61.6 years) with only a focal CBD stricture comprised the sample for this study (32 malignant and 18 benign strictures). The diagnosis of all malignant and five benign CBD strictures was confirmed by reviewing patients' surgical and pathology records; in 13 benign CBD strictures, the diagnosis was confirmed by means of clinical features. Multiphasic CT findings were analyzed with regard to the wall thickness, location, length, and enhancement pattern of the involved CBD, the upstream CBD diameter, and other findings. CT features to identify benign and malignant CBD strictures were compared by means of univariate analysis and multivariable stepwise logistic regression analysis. Malignant strictures were longer (17.9 mm +/- 6.6 [+/- standard deviation]) than benign strictures (8.9 mm +/- 6.8) (P < .0001), and upstream CBD diameters were larger in malignant cases (22.0 mm +/- 5.4) than in benign cases (17.8 mm +/- 4.6) (P = .033). The involved wall thickness was more than 1.5 mm in 26 malignant cases and three benign cases (P < .0001). During both hepatic arterial and portal venous phases, greater enhancement than that in the normal CBD were more frequently observed in malignant cases (in 27 and 30 patients for hepatic arterial and portal venous phase scans, respectively) than in benign cases (in two and three patients, respectively) (P < .0001). Results of multivariable stepwise logistic regression analysis showed that hyperenhancement of the involved CBD during the portal venous phase was the only variable that could be used to independently differentiate malignant from benign strictures. Hyperenhancement of the involved CBD during the portal venous phase is the main factor distinguishing malignant from benign CBD strictures.

Fungal Liver Infection in Immunocompromised Patients: Depiction with Multiphasic Contrast-enhanced Helical CT

To retrospectively assess multiphasic (nonenhanced, arterial phase, and portal venous phase) computed tomography (CT) of the liver for depiction of hepatic fungal infection in immunocompromised patients. The institutional ethics review board approved the study and waived the requirement for informed consent. Sixty multiphasic hepatic CT examinations were performed in 39 immunocompromised patients who fulfilled the criteria for having probable or proved fungal liver infection. The detection and conspicuity of focal liver lesions were assessed on scans obtained during each CT phase. The lesion enhancement pattern was determined, and, accordingly, lesions were stratified into two groups: lesions suggestive of infection (with ring enhancement patterns or high attenuation) and nonspecific hypoattenuating lesions. Statistical analyses were performed by using logistic regression with generalized estimating equations. A total of 536 liver lesions detected at 36 CT examinations with results positive for fungal infection were assessed. All 36 (100%) examinations yielded positive results during the arterial phase, whereas 25 (69%) of them yielded positive results during the portal venous phase (P < .001). At lesion-by-lesion analysis, the arterial phase scans depicted significantly more lesions (483 of 536 [90%]) than the portal venous phase (329 of 536 [61%]) and nonenhanced (265 of 465 [57%]) scans (P < .001 for both comparisons). In addition, on arterial phase scans, 386 of 483 lesions, as compared with 134 of 329 lesions on portal venous phase scans (P < .001), were judged to have an enhancement pattern suggestive of infection. The CT phases did not differ significantly in terms of the conspicuity of detected lesions. In patients suspected of having hepatic fungal infection, arterial phase CT depicts significantly more hepatic lesions than does CT performed during the other phases, and it reveals more lesions with enhancement patterns suggestive of infection. Arterial phase CT should be performed in addition to portal venous phase CT in patients suspected of having hepatic fungal infection.

Detecting Postsurgical Recurrent Hepatocellular Carcinoma With Multiphasic Helical Computed Tomography

The aim of this study was to assess the computed tomography (CT) patterns of postoperative recurrent hepatocellular carcinoma (HCC). Of 84 patients with histologically proven HCC by hepatectomies, multiphasic helical CT demonstrated 54 HCC lesions of intrahepatic recurrence in 31 (37%) patients. The initial and final appearances of HCC on hepatic arterial phase images were retrospectively determined by the serial CT scans, which were compared with appearances of primary HCC. The initial appearances of 54 recurrent HCCs were identical to the appearances of primary HCC in 41 (76%) lesions. Serial changes from the initial appearance to the final appearance of recurrent HCC were observed in 10 (42%) of 24 lesions. The 13 discordant lesions and the 10 lesions with altered lesion vascularity in our series implied that at least 43% were of multicentric occurrence. More than 40% of postoperative recurrent HCCs show intranodular hemodynamic changes. The incompatibility between CT findings of primary and recurrent HCCs implies that these tumors contain nodules of multicentric occurrence.

Inferior Mesenteric Artery Embolization before Endovascular Aneurysm Repair: Technique and Initial Results

To report a single center's technique and initial results in the preoperative embolization of the inferior mesenteric artery (IMA) before endovascular aneurysm repair (EVAR). Over a 3-year period, 102 patients at a single clinical site, including 86 men and 16 women aged 54-93 years (mean, 75 years), were found to have a patent IMA on computed tomographic (CT) angiography before EVAR. Coil embolization was performed after subselective catheterization with use of microcoils placed in the IMA proximal to the origin of the left colic artery. All patients in whom the IMA was visualized on flush aortography and successfully accessed underwent embolization. One month and 6 months after surgery, results in this cohort were retrospectively compared with those from a similar group of patients who underwent EVAR during the same period. These patients had patent IMAs on preoperative CT angiography but did not undergo embolization as a result of nonvisualization during flush aortography. All patients underwent EVAR with bifurcated modular devices with proximal transrenal fixation. All patients underwent postoperative follow-up with multiphase CT angiography to detect the presence of endoleak. Six-month follow-up data were available for 18 patients who underwent embolization and 54 patients who did not. Change in sac diameter was compared in these patients. Embolization was technically successful in 30 of 32 patients (94%) in whom it was attempted. There were no complications. At 1-month follow-up, five of 30 patients in the embolization group were noted to have a type II endoleak (17%). None of the endoleaks in this group were related to the IMA. The group with patent IMAs who did not undergo preoperative embolization had a 42% incidence of type II endoleak (P < .05). At 6 months after surgery, three of 18 patients who had undergone embolization (17%) had a type II endoleak, compared with 26 of 54 in the other group (48%; P < .05). Among the patients in whom 6-month data were available, mean changes in sac diameter were -5.2 mm (range, -24 to 2 mm) in the embolized group and -2.1 mm (range, -19 to 8 mm) in the nonembolized group. These initial results demonstrate that embolization of the IMA with subselective microcoils before EVAR is a safe and effective procedure to reduce the incidence of type II endoleaks. The data also suggest that preoperative embolization of the IMA is associated with greater shrinkage of aneurysm sac diameter at 6 months.

Moderate versus High Concentration of Contrast Material for Aortic and Hepatic Enhancement and Tumor-to-Liver Contrast at Multi–Detector Row CT

To prospectively evaluate aortic and hepatic enhancement and depiction of hypervascular hepatocellular carcinoma (HCC) between two contrast materials with moderate and high iodine concentrations when administered at same iodine dose and injection duration at multi-detector row helical computed tomography (CT). Institutional review board approval and informed patient consent were obtained. One hundred eighty-six patients were studied, and 67 patients with hypervascular HCC were identified. Ninety-four patients were assigned to receive iohexol 350 (mg iodine per milliliter) with protocol A; 92, iohexol 300 with protocol B. In both protocols, iohexol with same iodine load per weight (518 mg/kg) was administered with same injection duration (25 seconds). Multiphase CT scanning was started 10, 20, 50, and 180 seconds after the trigger (threshold level set at increase of 100 HU over baseline CT number of aorta). Enhancement of aorta and liver was measured in 186 patients. Tumor-to-liver contrast was measured in 67 patients with hypervascular HCC. Statistical analysis was performed with Mann-Whitney U test. Medians of aortic enhancement during four phases were 325, 185, 112, and 69 HU with protocol A. Corresponding values were 344, 266, 121, and 73 HU with protocol B. During all phases, aortic enhancement was significantly higher with protocol B (P = .046, P < .001, P < .001, and P = .002). Hepatic enhancement during four phases was 6, 21, 48, and 34 HU with protocol A. Corresponding values were 3, 17, 47, and 35 HU with protocol B. Hepatic enhancement was significantly higher with protocol A during first and second phases (P < .001 for both), although there was no significant difference between protocols during third and fourth phases (P = .778 and P = .178, respectively). Medians of tumor-to-liver contrast during four phases were 22, 34, 0.5, and -1.1 HU with protocol A. Corresponding values were 23, 45, 0, and -8.6 HU with protocol B. Tumor-to-liver contrast was significantly higher with protocol B during second phase (P = .049), although there was no difference between protocols during other phases. When total iodine dose was adjusted to body weight and injection duration was fixed, rapid administration of moderate concentration of contrast material was more effective for depiction of hypervascular HCC than was high concentration of contrast material.

Bladder cancer: analysis of multi-detector row helical CT enhancement pattern and accuracy in tumor detection and perivesical staging.

To evaluate the enhancement pattern of bladder cancer and the accuracy of multi-detector row helical computed tomography (CT) in the detection and staging of bladder cancer. In 20 patients, the attenuation value of bladder cancer was measured on dynamic contrast material-enhanced multiphasic CT images obtained with scanning delays of 40, 60, 80, and 100 seconds. In 67 patients, CT data were obtained with a 60-second scanning delay that covered the bladder (section thickness, 2.5 mm; beam pitch, 1.5) and a 180-second scanning delay that covered the abdomen (section thickness, 5 mm; beam pitch, 1.5). We prospectively evaluated CT images and compared findings at CT with findings at histologic examination. We evaluated cancer detection rate, positive predictive value of cancer detection, and sensitivity and specificity in the diagnosis of perivesical invasion. The attenuation value of bladder cancers was significantly higher on 60- (105 HU +/- 16) and 80-second (97 HU +/- 15) delayed CT images than on the other images (P <.05). The cancer detection rate and positive predictive value for cancer detection were 97% and 95%, respectively, in 67 patients and increased to 100% and 100%, respectively, in 44 patients with a time interval of 7 or more days between transurethral resection of the bladder (TURB) and CT examination. Sensitivity and specificity in the diagnosis of perivesical invasion were 89% and 95%, respectively, in 67 patients and increased to 92% and 98%, respectively, in 44 patients with a time interval of 7 or more days between TURB and CT examination. Bladder cancer tends to show peak enhancement with the 60-second scanning delay. Multi-detector row helical CT is useful in the detection and staging of bladder cancer.

Multiphasic helical computed tomography predicts subsequent development of severe brain edema in acute ischemic stroke.

To evaluate the use of multiphasic helical computed tomography (CT) in predicting subsequent development of severe brain edema in patients with acute middle cerebral artery (MCA) stroke. Case-control study. Tertiary referral hospital. We studied 31 patients with acute MCA stroke who had a baseline National Institutes of Health Stroke Scale score of 15 or higher within 6 hours of symptom onset. Sequential 4-phasic enhanced helical CT scans were performed after taking precontrast CT scans. The severity of perfusion deficit was graded as "severe" or "moderate" depending on collateral blood flow. Patients were classified as having severe brain edema if they showed signs of uncal herniation or deterioration with mass effect leading to hemicraniectomy. Severe brain edema developed in 10 patients (32%). Severe perfusion deficit greater than 50% of the presumed MCA territory on multiphasic helical CT was more often found in patients with severe brain edema than in those without (8 of 10 vs 4 of 21, P =.002). In contrast, parenchymal hypodensity greater than 50% on precontrast CT was observed only in 5 patients with severe brain edema (5 of 10 vs 4 of 21, P =.10). Additional involvement of the anterior or posterior cerebral artery territory was found on multiphasic CT (6 of 10 vs 0 of 21, P <.001) and on precontrast CT (4 of 10 vs 0 of 21, P =.007) only in patients with severe brain edema. Multiphasic helical CT is more useful than precontrast CT for predicting subsequent severe brain edema in acute MCA stroke based on the findings of severe perfusion deficit greater than 50% of the MCA territory and additional involvement of the anterior or posterior cerebral artery territory.

Malignant middle cerebral artery infarction in hyperacute ischemic stroke: evaluation with multiphasic perfusion computed tomography maps.

The purpose of this study was to compare the incidence of large hypoperfusion (greater than two-thirds of MCA territory) on computed tomography (CT) perfusion maps between hyperacute middle cerebral artery (MCA) stroke patients without or with malignant cerebral edema. Twenty-seven patients diagnosed with a hyperacute MCA stroke who had an initial National Institutes of Health Stroke Scale (NIHSS) score greater than 10 were included. Multiphasic perfusion CT was performed within 6 hours of symptom onset. Patients were divided into 2 groups: the malignant group (n = 11), composed of patients who died within 7 days, and the nonmalignant group, which included all other patients (n = 16). Unenhanced CT and CT perfusion maps were assessed and compared between the 2 groups with special emphasis on examining the CT findings, including hyperdense MCA sign, large (greater than two-thirds) hypoattenuation and hypoperfusion in the MCA territory, and hypoattenuation in the basal ganglia and other vascular territories. The incidence of large hypoattenuation (greater than two-thirds of MCA territory) on unenhanced CT and large hypoperfusion on CT perfusion maps differed significantly between the 2 groups (P < 0.05). Large hypoperfusion on the CT total perfusion map was most accurate (93%) among various CT findings for the prediction of malignant MCA infarction with high sensitivity (91%), specificity (94%), and positive predictive value (91%). The incidence of large hypoperfusion on a CT perfusion map was higher in the malignant group than the nonmalignant group. CT perfusion maps may provide added information about cerebral perfusion and could be a useful predictor of malignant MCA infarction.

Radiofrequency ablation of liver cancer: early evaluation of therapeutic response with contrast-enhanced ultrasonography.

The early assessment of the therapeutic response after percutaneous radiofrequency (RF) ablation is important, in order to correctly decide whether further treatment is necessary. The residual unablated tumor is usually depicted on contrast-enhanced multiphase helical computed tomography (CT) as a focal enhancing structure during the arterial and portal venous phases. Contrast-enhanced color Doppler and power Doppler ultrasonography (US) have also been used to detect residual tumors. Contrast-enhanced gray-scale US, using a harmonic technology which has recently been introduced, allows for the detection of residual tumors after ablation, without any of the blooming or motion artifacts usually seen on contrast-enhanced color or power Doppler US. Based on our experience and reports in the literature, we consider that contrast-enhanced gray-scale harmonic US constitutes a reliable alternative to contrast-enhanced multiphase CT for the early evaluation of the therapeutic response to RF ablation for liver cancer. This technique was also useful in targeting any residual unablated tumors encountered during additional ablation.

Hereditary hemorrhagic telangiectasia: multi-detector row helical CT assessment of hepatic involvement.

To describe findings obtained with multi-detector row helical computed tomography (CT) of the liver in patients with hereditary hemorrhagic telangiectasia. Multiphasic multi-detector row helical CT was performed in 70 consecutive patients (29 females and 41 males; mean age, 48.5 years; age range, 15-75 years): 64 considered to have hereditary hemorrhagic telangiectasia and six suspected of having the disease. Scanning delay was achieved by using a test bolus of contrast medium to obtain early arterial phase, late arterial phase, and portal venous phase images. Multiplanar and angiographic reconstructions were then generated. The presence of shunts, hepatic perfusion disorders, telangiectases, other vascular lesions, indirect signs of portal hypertension, and vascular anatomic variants were evaluated by two radiologists in consensus. Fifty-two of 70 (74%) patients had hepatic vascular abnormalities. Only four of 52 (8%) patients were symptomatic. Arterioportal shunts were present in 27 of 52 (52%) patients, arteriosystemic shunts in eight of 52 (15%), and both shunt types in 17 of 52 (33%). In 34 of 52 (65%) patients, parenchymal perfusion disorders were detected. Telangiectases were found in 33 of 52 (63%) patients. Large confluent vascular masses were identified in 13 of 52 (25%) patients. In 31 of 52 (60%) patients, indirect CT signs of portal hypertension were detected, but only one had clinical signs of this condition. Vascular anatomic variants were detected in seven patients (13%). Multi-detector row helical CT and reconstructions depict the complex hepatic vascular alterations typical of hereditary hemorrhagic telangiectasia.

Telangiectatic focal nodular hyperplasia: US, CT, and MR imaging findings with histopathologic correlation in 13 cases.

To review the ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) imaging findings in 13 patients with telangiectatic focal nodular hyperplasia (FNH) and to compare imaging features with histopathologic results from resected specimens. US, helical multiphasic CT, and MR images in 13 patients with pathologically proven telangiectatic FNH were reviewed retrospectively. Two abdominal radiologists evaluated lesions for number, size, heterogeneity, surface characteristics, presence of a central scar, presence of a pseudocapsule, US appearance, attenuation at CT, signal intensity at MR imaging, and presence of associated lesions. Imaging and pathologic findings were compared. Sixty-one lesions (5-140 mm in diameter) were seen at imaging. Lesions were multiple in eight of 13 (62%) patients. Imaging characteristics were heterogeneity in 26 of 61 lesions (43%), well-defined margins in 43 of 61 (70%), lack of a central scar in 56 of 61 (92%), presence of a pseudocapsule in three of 61 (5%), hyperintensity on T1-weighted MR images in 17 of 32 (53%), strong hyperintensity on T2-weighted MR images in 24 of 54 (44%), and persistent enhancement on delayed contrast material-enhanced CT or T1-weighted MR images in 23 of 38 (61%). No specific US pattern was noted. Two patients had additional lesions: One had classic FNH, and the other had a cavernous hemangioma. Hyperintensity on T1-weighted MR images was due to sinusoidal dilatation. Hyperintensity on T2-weighted MR images correlated well with the presence of inflammation. Telangiectatic FNH differs from typical FNH at imaging: Atypical FNH features often observed with telangiectatic FNH are lack of a central scar, lesion heterogeneity, hyperintensity on T1-weighted MR images, strong hyperintensity on T2-weighted MR images, and persistent contrast enhancement on delayed contrast-enhanced CT or T1-weighted MR images.

Hepatocellular carcinoma: prediction of blood supply from right inferior phrenic artery by multiphasic CT.

Recurrent hepatocellular carcinoma (HCC) often occurs with extrahepatic arterial supply (parasitic supply), essentially due to liver intraarterial chemoembolization, which could potentially hamper retreatment. The right inferior phrenic artery (RIPA) is the most frequent extrahepatic feeding artery. We investigated computed tomography (CT) findings of parasitic supply by the RIPA, and discuss the utility of multiphasic CT for prediction of parasitic supply from RIPA. Medical records, CT scans, and angiograms in 20 patients with HCC fed by RIPA were reviewed. Forty-two patients with HCC but without parasitic supply were enrolled as the control group. After injection of contrast medium (300 mg I/mL) at a rate of 3 mL/s (total amount, 100 mL), CT images were obtained at 30 seconds, 60 seconds, and 150 seconds with scanning parameters of 7-mm collimation, 1:1 pitch, and 3.5-mm reconstruction. Two radiologists evaluated the previous treatment, patency of the hepatic arteries, location of tumors, and detectability and diameter of the RIPA. CT demonstrated at least one portion of RIPA in all patients in both groups. The distal portions of RIPA were detected on CT more frequently in the parasitic group (75%) than in the control group (7.1%). The mean diameter of the RIPA in the parasitic group was 2.3 mm (range; 1.6-3.8), and was larger than that of the control group (mean; 1.3 mm and range; 0-4.1mm) with statistical significance (P < 0.01). Multiphasic CT could demonstrate the presence of parasitic supply to HCCs from RIPA. Visualization of RIPA at the distal portion on CT would be a clue of parasitic supply from RIPA.

Improved detection of renal pathologic features on multiphasic helical CT compared with IVU in patients presenting with microscopic hematuria

Objectives To examine the virtues of multiphasic helical computed tomography (CT) in the diagnosis of upper urinary tract lesions refractory to identification by intravenous urography (IVU). Methods A total of 86 patients (59 men and 27 women), 27 to 88 years old, with microscopic hematuria and negative IVU findings were examined with multiphasic helical CT consisting of a pre-enhancement, late arterial–early cortical–medullary, nephrographic, and excretory phase helical CT of the kidneys, using 3 to 5-mm collimation and 7.5-mm/s table feed. Results The multiphasic helical CT was conclusive in 84 lesions. Twenty-five cases of early papillary and medullary necrosis, 7 of 8 inflammatory lesions, 3 caliceal diverticula, 1 lupus nephritis, 26 small calculi, 2 medullary sponge kidney, 5 vascular anomalies, and 3 infarcts presented with characteristic manifestations on CT but lacked findings on IVU. Similarly 8 of 9 small malignant neoplasms, 2 small benign neoplasms, and 2 small cysts produced no detectable findings on IVU but were readily diagnosed on helical CT. Conclusions Characteristic findings, particularly on late arterial, early corticomedullary, parenchymal, and excretory phase helical CT make possible the diagnosis of early inflammatory disease, small masses and neoplastic lesions, and vascular abnormalities. Limited resolution (needed to identify small calculi) and the lack of ability to capture phases significantly reduce the diagnostic ability of IVU.

Epithelioid Hemangioendothelioma of the Liver: Helical CT Findings

Purpose: To describe the morphologic features and enhancement patterns of the helical computed tomography (CT) observed in patients with epithelioid hemangioendothelioma (EH) of the liver. Materials and Methods: Seven patients (four men and three women; mean age, 41 years) with pathologically proven EHs underwent monophasic (n=2), biphasic (n=2) or triphasic (n=3) helical CT, and the findings were retrospectively analysed. The morphologic features to which attention was directed were tumor number, size, location, shape, margin, surface, the presence of adjacent capsular retraction, vascular encasement and confluent mass formation, while the enhancement pattern was examined in terms of the appearance and degree of enhancement during the arterial or portal phase, and enhancement change during the portal and equilibrium phases. Results: Six patients had multiple tumors, and one had a single lesion. The maximon diameter of these tumors ranged from 0.5 to 12.0 (mean, 3.2) cm, and almost all occurred in the peripheral portion of the liver. The shape, margin and surface features of the tumors varied: in four patients, the margin was poorly defined and the surface was smooth, while in five, adjacent capsular retraction was observed. Vascular encasement was noted in five of six patients with hepatic vessels abutting the tumors, and in all three who were follow up, the growth pattern involved confluent mass formation. In all patients, many tumors showed either nodular (n=3) or irregular (n=4) peripheral enhancement. In all five patients who underwent multiphasic CT, centripetal enhancement was demoustrated. Conclusion: Our results disclosed that most patients with EH had multiple tumors, and that almost all were located in the peripheral portion of the liver and involved capsular retraction. The other common CT findings were vascular encasement and a centripetal enhancement pattern. When these CT findings are observed in patients with hepatic tumors, EH should be included in the differential diagnosis.

Use of radiologic techniques to screen for hepatocellular carcinoma.

The role of imaging in screening and evaluation of cirrhotic patients is to assess the extent of cirrhosis and portal hypertension (liver morphology, varices, ascites, vessel patency) and to detect hepatocellular carcinoma (HCC). Ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) have valuable roles, with catheter angiography usually reserved for specific problem solving. Ultrasonography is highly operator-dependent, and detection of focal masses is often difficult or impossible because of large patient body habitus and hepatic steatosis and fibrosis, which attenuate the ultrasound beam. For sonography, as well as CT and MRI, the use of intravenous contrast material with multiphasic imaging (arterial, portal venous, and delayed) is essential to accurately depict the morphology and hemodynamics of focal hepatic lesions. Computed tomography and MRI are highly accurate in diagnosis of large HCC but are much less accurate for lesions less than 2 cm in diameter. Many factors influence the choice and timing of imaging tests, including the etiology of the chronic liver disease, the elevation of serum tumor markers, and the availability and excellence of equipment and personnel. In our practice, helical multiphasic CT is obtained at least every 12 months, more frequently in patients judged to be at high risk for HCC.