CT Arterial Portography Research Articles

Hemodynamic Change by Portal Tumor Thrombus in Hepatocellular Carcinoma : Evaluation by Combined Spiral CT Hepatic Arteriography and CT Arterial Portography

Hemodynamic Change by Portal Tumor Thrombus in Hepatocellular Carcinoma : Evaluation by Combined Spiral CT Hepatic Arteriography and CT Arterial Portography

Pattern analysis of Hemodynamic Changes of the Liver on Combined CT Hepatic Arteriography and CT ArterialPortography

Pattern analysis of Hemodynamic Changes of the Liver on Combined CT Hepatic Arteriography and CT ArterialPortography

Malignant hepatic hilar tumors: can ultrasonography be used as an alternative to angiography with CT arterial portography for determination of resectability?

Nineteen consecutive patients with malignant hilar obstruction were imaged with angiography, CT portography, and ultrasonography with color and spectral Doppler technique; all had surgical pathologic correlation. At surgery, 12 of 19 patients (63%) were found to have portal vein involvement; 15 of 19 (79%) had parenchymal invasion; and 11 of 19 (58%) had lobar atrophy. Level of biliary obstruction was determined in seven of 19 patients (37%) without drainage catheters. No difference was found between ultrasonography and angiography with CT portography for diagnosis of atrophy, level of bile duct obstruction, hepatic involvement, or venous invasion. Extrahepatic metastases in nine of 19 patients (47%) were poorly predicted by both CT portography and ultrasonography.

Malignant hepatic hilar tumors: can ultrasonography be used as an alternative to angiography with CT arterial portography for determination of resectability?

Nineteen consecutive patients with malignant hilar obstruction were imaged with angiography, CT portography, and ultrasonography with color and spectral Doppler technique; all had surgical pathologic correlation. At surgery, 12 of 19 patients (63%) were found to have portal vein involvement; 15 of 19 (79%) had parenchymal invasion; and 11 of 19 (58%) had lobar atrophy. Level of biliary obstruction was determined in seven of 19 patients (37%) without drainage catheters. No difference was found between ultrasonography and angiography with CT portography for diagnosis of atrophy, level of bile duct obstruction, hepatic involvement, or venous invasion. Extrahepatic metastases in nine of 19 patients (47%) were poorly predicted by both CT portography and ultrasonography.

Segmented areas of increased attenuation in the liver caused by right adrenal tumors: CT features.

Our goal was to describe attenuation differences bordered by a straight line in the right hepatic lobe on enhanced CT in patients with right adrenal tumors and to discuss the cause of this appearance. Three patients showing attenuation differences bordered by a straight line were discovered in the CT files of 26 cases of right adrenal tumor over 3 cm in diameter. All CT scans were examined by incremental dynamic study. Two patients had large zone of hyperattenuation in the right lobe bordered with a straight line intersecting both anterior branches of the right portal vein and the inferior vena cava (IVC). A third patient and one of the two patients mentioned already had zones of relative hyper- and hypoattenuation in the medial portion of the posterior hepatic segment, respectively. All three patients had large right adrenal tumors, which severely compressed the right hepatic vein near its confluence with the IVC and/or the IVC in or below its intrahepatic portion. The distribution of attenuation differences was similar to the hyperattenuation at CT arteriography or perfusion defect at CT arterial portography under temporary balloon occlusion of the right hepatic vein and inferior right hepatic vein, respectively. Straight-bordered attenuation differences within the right hepatic lobe at dynamic CT can be caused by compression of the right hepatic vein by large right adrenal tumors.

Lesion visualization by targeted computed tomography liver enhancement in dogs

We conducted a pilot study to determine the potential advantages of using liver-specific targeted computed tomography (CT) contrast agents for lesion detection. Eight dogs had liver infarcts created by percutaneous injections of ethanol. Each dog underwent CT scans with four imaging techniques: unenhanced, intravenous contrast enhanced (IVCE), CT arterial portography (CTAP), and targeted liver enhancement with iodipamide ethylester (IDE) particles. Lesions were assessed quantitatively to determine liver-to-lesion density differences and the drop in density across liver edge as a quantitative measure of edge sharpness. Expert readers subjectively analyzed data to determine lesion visibility and edge sharpness. Liver-to-lesion density differences were greatest with CTAP (56.4 +/- 35.5 Hounsfield units [H]) followed by IDE (41.1 +/- 7.0 H), i.v. (22.7 +/- 6.0 H), and unenhanced scans (13.6 +/- 4.1 H; ps < .05 for CTAP versus unenhanced and IDE versus unenhanced). Edges were best defined both subjectively and quantitatively on IDE-enhanced scans. Targeted liver-specific contrast agents have potential to increase lesion visibility when compared with standard i.v. contrast enhancement of the liver by increasing lesion edge definition and liver-to-lesion attenuation differences. Further work in animal tumor models, and clinical trials as agents become available, appears justified.

Serial hemodynamic measurements in well-differentiated hepatocellular carcinomas

We performed serial hemodynamics in 15 patients with 21 well-differentiated hepatocellular carcinomas. The total length of the observation period ranged from 129 to 678 days (median, 368). We investigated both arterial and portal blood flow at intervals of at least 4 months. Arterial blood flow was measured with carbon dioxide-enhanced ultrasonography (US), and portal blood flow was measured with computed tomographic arterial portography (CTAP). None of the tumors were hypervascular on the initial study; however, by the final study nine nodules (42.9%) had become homogeneously hypervascular, two (9.5%) had become partially hypervascular, and the others did not change. Of 10 nodules without portal blood supply on any study, 8 became hypervascular by the final study. Of 11 nodules with portal blood supply on the initial study, a follow-up study showed no change in portal flow in 6 and the loss of portal flow in 5. Four of these five became hypervascular, with a documented loss of portal flow before the increase in arterial flow. The doubling time of tumors with a homogeneous increase in arterial blood flow ranged from 89 to 333 days (median, 172), whereas the doubling time of other tumors ranged from 227 to 607 days (median, 392). Thus, growth rate and vascularity in well-differentiated hepatocellular carcinoma are closely correlated. When the well-differentiated hepatocellular carcinoma has portal blood flow and is not hypervascular, it grows slowly. On the other hand, when it loses portal blood flow and becomes hypervascular, it grows rapidly.

Serial hemodynamic measurements in well-differentiated hepatocellular carcinomas

We performed serial hemodynamics in 15 patients with 21 well-differentiated hepatocellular carcinomas. The total length of the observation period ranged from 129 to 678 days (median, 368). We investigated both arterial and portal blood flow at intervals of at least 4 months. Arterial blood flow was measured with carbon dioxide-enhanced ultrasonography (US), and portal blood flow was measured with computed tomographic arterial portography (CTAP). None of the tumors were hypervascular on the initial study; however, by the final study nine nodules (42.9%) had become homogeneously hypervascular, two (9.5%) had become partially hypervascular, and the others did not change. Of 10 nodules without portal blood supply on any study, 8 became hypervascular by the final study. Of 11 nodules with portal blood supply on the initial study, a follow-up study showed no change in portal flow in 6 and the loss of portal flow in 5. Four of these five became hypervascular, with a documented loss of portal flow before the increase in arterial flow. The doubling time of tumors with a homogeneous increase in arterial blood flow ranged from 89 to 333 days (median, 172), whereas the doubling time of other tumors ranged from 227 to 607 days (median, 392). Thus, growth rate and vascularity in well-differentiated hepatocellular carcinoma are closely correlated. When the well-differentiated hepatocellular carcinoma has portal blood flow and is not hypervascular, it grows slowly. On the other hand, when it loses portal blood flow and becomes hypervascular, it grows rapidly.

The association of paracardial adenopathy with hepatic metastasis found on CT arterial portography.

The association of paracardial lymphadenopathy with hepatic metastases in patients undergoing computed tomographic arterial portography (CTAP) prior to possible resection of hepatic metastases is documented. CTAP was performed on 45 patients with hepatic metastasis, including 30 with colorectal carcinoma, using 1 cm increments from the dome of the diaphragm through the liver. Two radiologists, blinded to the diagnosis and surgical results, reviewed all portograms and identified all paracardial lymph nodes larger than 8 cm. Enlarged paracardial lymph nodes were found in three of the 30 colorectal carcinoma patients and two of the remaining 15 patients. All three colorectal patients with paracardial lymphadenopathy demonstrated massive metastatic involvement of the anterior segment of the right hepatic lobe (segment 8: Couinaud nomenclature). Additional metastasis in the superior aspect of the liver was seen in two of these patients as well. Both patients without colorectal carcinoma with paracardial lymphadenopathy had metastasis involving the superior aspect of the liver. Paracardial lymphadenopathy was right-sided in all five patients and bilateral in one. By contrast, 48% (19 of 40) of patients without enlarged paracardial lymph nodes had metastasis in the anterior segment of the right lobe. This study suggests that paracardial lymphadenopathy is associated with metastatic disease to specific areas within the liver. This nodal involvement can be attributed to lymphatic drainage from the diaphragmatic surface of the liver.

Miscellaneous liver disorders

Liver disorders in pregnancy range from mild asymptomatic biochemical changes to fulminant hepatic failure. Advances in the management of a number of serious conditions have lead to improvement in maternal and fetal survival. Hepatobiliary complications of total parenteral nutrition appear to occur more commonly in patients with preexisting liver disease. Peliosis hepatis is associated with a variety of conditions including tuberculosis, malignancy, anabolic steroids, Rochalimea henselae infection with HIV infection, and azathioprine therapy post-renal transplantation. The value of magnetic resonance imaging in the identification of specific benign hepatic tumors has added to the diagnostic armamentarium in these disorders. Also, computed tomography arterial portography can be used to detect hepatocellular carcinomas and to differentiate between adenomas and hepatic cancers. The documented association between hepatic adenomas and their transformation to hepatic cancers is extremely rare. Nevertheless, the discontinuation of oral contraceptives, if applicable, should be advocated. The treatment of hepatic metastases due to carcinoid or islet cell carcinomas entails a variety of regimens ranging from pharmacotherapy, chemotherapy, and surgery.

Postsurgical Intrahepatic Portal Thromboembolism

Our goal was to investigate unexplained nontumorous perfusion defects on CT arterial portography (CTAP). The CTAP images of 35 patients who underwent partial hepatectomy or open biopsy were analyzed. Hepatic tumors consisted of hepatocellular carcinoma (n = 18) and colorectal carcinoma metastases (n = 17). Nontumorous perfusion defects were categorized into those previously explained and those unexplained. We investigated unexplained ones and their relationship with the underlying conditions. Eight unexplained nontumorous perfusion defects were found in four patients with colorectal metastases. Statistical analysis showed that the defects occurred with significantly higher incidence in patients with colorectal metastases than in those with hepatocellular carcinoma (p = 0.046, Fisher test). All four patients with defects underwent CTAP within 1 month after colorectal surgery. A significant difference was seen in the distribution of surgery-CTAP time intervals between those patients with and those without defects (p < 0.05, Wilcoxon-Mann-Whitney test). Intrahepatic portal thrombi were pathologically proven in one of the four patients. Unexplained nontumorous hepatic perfusion defects may represent postsurgical portal thromboemboli.

CT arterial portography for detecting recurrent hepatic metastases.

CT arterial portography for detecting recurrent hepatic metastases.

Does advanced cirrhosis with portosystemic shunting affect the value of CT arterial portography in the evaluation of the liver?

The purpose of this study was to determine the extent to which reduced portal blood flow in patients with advanced cirrhosis affects contrast enhancement of the liver during CT arterial portography (CTAP). We postulated that reduced and/or irregular hepatic enhancement would limit the efficacy of CTAP for the detection of hepatic tumors in these patients. We reviewed the records of 82 patients who had biopsy-proved advanced cirrhosis and who underwent CTAP. Three experienced radiologists evaluated the CTAP studies for adequacy of hepatic parenchymal enhancement. The presence or absence of varices also was documented in an attempt to select a subgroup of patients in whom CTAP showed better hepatic parenchymal enhancement. Forty-seven (57%) of 82 patients had inadequate hepatic parenchymal enhancement to allow an evaluation of the entire liver. Inadequacy was attributable to areas of hyperdense parenchymal enhancement, areas of diffuse nontumoral mottling, or zones of poor parenchymal enhancement (soft-tissue attenuation equal to that of the paraspinal muscle). Parenchymal enhancement was inadequate in 62% of patients with varices and in 28% of patients without demonstrable varices. Our results show that contrast enhancement of the liver during CTAP is altered significantly in patients with cirrhosis. Thus, it is likely that CTAP has limited usefulness for the detection or characterization of hepatic neoplasms in patients with cirrhosis.

Optimizing CT portography: a prospective comparison of injection into the splenic versus superior mesenteric artery.

To evaluate whether computed tomographic arterial portography (CTAP) is best performed with injections in the superior mesenteric artery (SMA) or the splenic artery. Seventy-one studies were performed with injection into the SMA (n = 37) or splenic artery (n = 34) of 150 mL of contrast material at 1.5 mL/sec and 20-second delay for both groups. Images were reviewed for location and type of nontumoral perfusion abnormalities. The degree of liver parenchymal enhancement with each technique was compared. Fewer nontumoral perfusion defects were seen with splenic artery (65%) versus SMA (78%) injection. Visual differences in contrast enhancement with greater attenuation in dependent portions of the liver were seen with greater frequency with SMA (41%) than with splenic artery (24%) injection. Contrast enhancement that obscured detail in the right lobe was seen only with SMA injections (16%). Greater parenchymal enhancement (up to 18 HU) at all time intervals was seen with splenic artery injection. Because of greater parenchymal enhancement and fewer nontumoral perfusion abnormalities, splenic artery catheterization is the preferred technique for CTAP.

Spiral Computed Tomography Arterial Portography With Three-Dimensional Volumetric Rendering for Oncologic Surgery Planning

Surgical resection of metastatic neoplasms of the liver can prolong survival of patients. The decision to resect a tumor depends to a great extent on the location of lesions relative to hepatic vasculature. Spiral computed tomography arterial portography (SCTAP) is an excellent technique for preoperative localization of tumors. The addition of three-dimensional rendering of image data sets should enhance the efficiency and accuracy of the interpretation of these data by the surgeon. Fourteen patients with surgically and pathologically proven solitary and multiple metastatic hepatic neoplasms underwent SCTAP: Volume data sets thus derived were used to produce life-like three-dimensional animated images through a process known as volumetric rendering. These images were presented to the surgeon, who evaluated them based on several criteria. Accurate and clinically useful images were produced routinely in 13 of 14 patients. Clinical utility of three-dimensional rendering of SCTAP data sets for preoperative localization of hepatic lesions has been shown retrospectively. A larger, prospective study is suggested to demonstrate the accuracy and efficacy of the technique.

CT arterial portography vs pancreatic arteriography in the assessment of vascular involvement in pancreatic and periampullary tumors.

Preoperative staging of pancreatic tumors is frequently accomplished through a combined effort of CT and arteriography. For tumor detection and delineation of disease extent CT is utilized routinely, with CT arterial portography (CTAP) being the single most accurate study for the detection liver metastases. Arteriography has remained the "gold" standard for assessing vascular involvement. The purpose of this study was to determine whether CTAP could become the single study of choice for assessing resectability in patients with pancreatic and periampullary tumors with particular emphasis on its accuracy in determining vascular involvement. Radiologic studies and medical records were reviewed in 20 patients who had received both CTAP and arteriographic examinations for preoperative assessment of pancreatic and periampullary tumors. These findings were correlated with results from either surgery (12 cases) or percutaneous biopsy and follow-up (8 cases) in 12 nonresectable and 8 resectable tumors. Arteriography and CTAP correctly concurred in 75% of cases (15 of 20); CTAP correctly demonstrated vascular involvement not appreciated on arteriography in 15% (3 of 20) with an overall sensitivity and specificity of 90 and 100%, respectively. Arteriography was superior to CTAP in one patient (5%) with an overall sensitivity and specificity of 70 and 90%, respectively, for predicting vascular involvement by tumor. Our experience suggests that CTAP is more accurate than arteriography for demonstrating tumor involvement of major peripancreatic vessels. Because CTAP, additionally, has a high sensitivity for detecting liver metastases, no further studies may be necessary to determine operability of these patients.

Nontumorous attenuation changes on CT arterial portography.

We prospectively studied the frequency and the distribution of nontumorous attenuation changes during CT arterial portography. Computed tomography arterial portograms were obtained in 67 consecutive patients. The frequency and distribution of nontumorous attenuation changes (pseudolesions, areas of hypo- or hyperperfusion) were analyzed and related to the size of the tumor, the vascular status assessed by Doppler examination, and the presence of chronic liver disease. Pseudolesions were detected in 19 patients (28%). They were typical in 13 cases and atypical (round shaped or located in the caudate or right lobe) in 6. Segmental, lobar, or diffuse perfusion defects were seen in 36 patients (54%). In 56% of the cases, they were adjacent to large tumors and related to compression or thrombosis of intrahepatic portal branches as demonstrated by sonographic and Doppler findings. Areas of hyperperfusion were detected in 14 patients (21%). Of these cases, eight (57%) were peritumoral hyperperfusion. In all cases, the mean diameter of the tumors was large and there was compression of adjacent hepatic vein as demonstrated by sonographic and Doppler findings. Nontumorous attenuation changes are common in CT arterial portography. Factors leading to these artifacts include size of the tumor and vascular consequences of the tumor. Sonographic and Doppler studies may play a role in predicting these factors.

CT angiography and CT arterial portography in evaluation of hepatic adenomas.

Our goal was to evaluate the contribution of CT arterial portography (CTAP) and CT angiography to accurate determination of disease extent in patients with known hepatic adenomas. Imaging results were reviewed in three women with known hepatic adenomas, all of whom had percutaneous biopsy to confirm the diagnosis. Results of CTAP studies in all patients as well as results of CT arteriography in one patient were compared with routine dynamic CT studies in all three and with MRI studies in two. The CTAP and CT arteriography demonstrated multiple additional lesions in all patients as compared with routine dynamic CT and MRI studies. In one of the patients who was found to have hepatic adenomatosis, the degree of tumor involvement changed the operative procedure from partial hepatectomy to liver transplantation. In patients with known hepatic adenomas who require surgery, CTAP provides more accurate preoperative staging of extent of liver replacement with tumor.

Combined CT arterial portography and CT hepatic angiography for evaluation of the hepatic resection candidate. Work in progress.

To determine whether the addition of computed tomographic (CT) angiography to CT arterial portography would improve lesion detection and heighten confidence in interpreting perfusion abnormalities. The two examinations were performed sequentially in 10 candidates for surgical resection of hepatic tumors. Arterial vascular access was obtained with bilateral punctures of the common femoral artery and selective placement of angiographic catheters in the hepatic artery and superior mesenteric artery (SMA). CT scans were obtained first during injection of contrast material into the SMA, followed by repeated imaging of the liver during injection of contrast material into the hepatic artery. The procedure demonstrated, among other results, three additional lesions in two patients, a possibly nontumorous abnormality as tumorous in one, and a suspected tumorous abnormality as nontumorous in one. Suspected nontumorous abnormalities in four patients were confirmed at CT angiography. These preliminary data support a trial of this technique in a larger population.

Focal Fatty Infiltration

The purpose of this work was to determine the frequency and significance of characteristic nontumorous low attenuation defects found in the left hepatic lobe during CT arterial portography (CTAP). Eighty CTAPs performed over a 17 month period were retrospectively reviewed to identify nonsegmental low attenuation defects adjacent to the falciform ligament, gallbladder, or porta hepatis. Twenty-four separate defects were present in 14 of 80 (18%) patients. Cases in which a defect was present were compared with MR, surgical findings, and pathology reports. The defects were oval or triangular in shape with a mean maximum diameter of 1.7 cm (range 1-5 cm). None of these defects were identified on MR in the 12 patients who underwent T1, T2, and STIR MR; however, 3 showed dropout of signal on chemical shift MR, suggesting fatty infiltration. In the 12 patients who underwent surgery, no lesion was shown to represent tumor. Two intraoperative biopsies of the area of the defects showed fatty infiltration. Nontumorous low attenuation defects adjacent to the gallbladder, falciform ligament, or porta hepatis are a pitfall of CTAP and can be associated with focal fatty infiltration, as well as decreased perfusion due to technical factors or a variation in hepatic vascular supply.