Comparison of detection pattern of HCC by ferumoxide-enhanced MRI and intratumoral blood flow pattern

We compared the detection rate and pattern of ferumoxide-enhanced magnetic resonance imaging (Fe-MRI) with the intratumoral blood flow pattern determined by CT angiography (CTA) and CT portography (CTAP) in 124 nodes (34 cases) diagnosed as hepatocellular carcinoma (HCC) or borderline HCC, based on the clinical course. Sequences to obtain a T1-weighted images (T1W), proton density-weighted images (PDW), T2-weighted images (T2W), T2*-weighted images (T2*W) were used in Fe-MRI. In nodes shown to be hypervascular on CTA, the detection rate by Fe-MRI was 69.7%. In nodes shown to be avascular by CTAP, the detection rate by Fe-MRI was 67.3%. These rates were higher than with other flow patterns. In nodes showing high signal intensity (HSI) on any sequences, arterial blood flow was increased and portal blood flow decreased in comparison with nodes without high signal intensity. All nodes showing HSI, both on Fe-MRI T2W and T2*W, were hypervascular on CTA, and portal blood flow was absent on CTAP. Nodes showing HSI on both T2*W and T2W were considered to have greater arterial blood flow and decreased portal blood flow compared with nodes appearing as HSI on T2*W, but only as iso- or low signal intensity on T2W (Mann-Whitney U-test; p < 0.05).     

Portal computed tomography. Methodology and indications]

CT arterioportography (CTAP) requires intra-arterial contrast material via the superior mesenteric (splenic) artery. Malignant hepatic tumors are characterized by arterial vascularization and only minimal portal blood supply. Portal contrast therefore reveals small tumors with a high sensitivity of 68-87%. Sensitivity is higher in metastatic tumors than in hepatocellular carcinomas. CTAP is the method of choice for evaluation of the number, size and location of hepatic tumors prior to surgical intervention. If the findings are unclear, additional magnetic resonance imaging and sonography during the operation are useful.     

Diagnosis of hepatic neoplasms using CT arterial portography and CT hepatic arteriography

Both computed tomography arterial portography (CTAP) and CT hepatic arteriography (CTHA) are CT techniques with angiographic assistance. The detection sensitivity of these techniques is high because marked lesion contrast can be obtained using direct delivery of contrast materials to the liver parenchyma or the tumors. The use of CTAP and CTHA may improve therapeutic results after transarterial embolization therapy for hepatocellular carcinomas because of their high diagnostic accuracy. Findings on CTAP or CTHA can sometimes help characterize the hepatic focal lesions. Thus, CTAP and CTHA are frequently performed as pretreatment examinations, although they are invasive compared to intravenous (IV) contrast-enhanced CT or magnetic resonance imaging. However, there are some potential pitfalls, such as nontumorous perfusion abnormalities. CTAP and CTHA are less effective for evaluation of patients with cirrhosis and portal hypertension. This article presents a current overview of CTAP and CTHA technique for diagnosis of hepatic neoplasms.     

CT during hepatic arteriography and portography: an illustrative review.

The combination of computed tomography (CT) during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) has been used for evaluation of hepatic neoplasms before partial hepatic resection. Focal hepatic lesions that can be demonstrated with CTAP and CTHA include regenerative nodules, dysplastic nodules, dysplastic nodules with malignant foci, hepatocellular carcinoma, cholangiocarcinoma, hemangioma, and metastases. CTAP is considered the most sensitive modality for detection of small hepatic lesions, particularly small hepatic tumors such as hepatocellular carcinoma and metastatic tumors. CTHA can demonstrate not only hypervascular tumors but also hypovascular tumors and can help differentiate malignant from benign lesions. However, various types of nontumorous hemodynamic changes are frequently encountered at CTAP or CTHA and appear as focal lesions that mimic true hepatic lesions. Such hemodynamic changes include several types of arterioportal shunts, liver cirrhosis, Budd-Chiari syndrome, inflammatory changes, pseudolesions due to an aberrant blood supply, and laminar flow in the portal vein. Familiarity with the CTAP and CTHA appearances of various hepatic lesions and nontumorous hemodynamic changes allows the radiologist to improve the diagnostic accuracy.     

肝脏磁共振血管造影术:与DSA及CTAP的比较研究

目的通过与DSA及CTAP的比较研究,评价动态增强MRA在肝移植受体术前血管系统检查中的应用价值。方法16例肝疾病患者在2周内行肝脏MRI及动态增强(利用SENSE技术)MRA、DSA和CT经动脉门脉造影(CTAP)检查。MRA图像重建自冠状位3D动态增强扫描,动脉期MRA与DSA比较,门脉期MRV与CTAP比较。动态增强MRA采用20ml造影剂和统一扫描延迟时间。结果动态增强MRA能很好显示肝动脉系统各主要分支及变异;MRV对门脉系统的显示质量等于甚至超过CTAP;MRV能很好显示下腔静脉;MRV尚意外发现了1例DSA上未能显示的血管变异。结论动态增强MRA能清晰显示肝移植受体术前的血管结构,其有可能成为原位肝移植受体术前首选的影像学检查手段。     

肝癌的CT血管造影

目的：介绍三种螺旋ＣＴ肝脏血管造影的方法，评价其对肝癌诊断的作用。材料和方法：用三种螺旋ＣＴ肝脏血管造影的方法对４９例肝癌患者作５１次检查：肝脏动脉造影ＣＴ（ＣＴＡ）、经动脉门静脉造影ＣＴ（ＣＴＡＰ）和经术中植入门静脉的药物输入系统（ＤＤＳ）直接门静脉造影ＣＴ（ＣＴＰ）。结果：这些方法可发现直径３ｍｍ的病灶，明确显示肿瘤的血供情况。结论：ＣＴＡ，ＣＴＡＰ和ＣＴＰ有利于肝脏多发和小肿瘤病灶的检出以及其鉴别诊断，ＣＴＡ和ＣＴＡＰ虽为创伤性检查，因其敏感性很高，可在肝脏肿瘤外科手术前和需明确肿瘤的血供时选用；对植入ＤＤＳ的患者，术后复查宜常规ＣＴＰ检查。     

Progression to hypervascular hepatocellular carcinoma: correlation with intranodular blood supply evaluated with CT during intraarterial injection of contrast material

PURPOSE: To analyze the correlation between intranodular blood supply of borderline lesions (ie, dysplastic nodules or hypovascular well-differentiated hepatocellular carcinoma [HCC] nodules) and their progression to hypervascular classic HCC in cirrhotic livers. MATERIALS AND METHODS: One hundred seventy-six borderline lesions seen at computed tomography (CT) during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) were evaluated in 49 patients with cirrhosis who underwent repeated CTAP and/or CTHA but no therapy. On the basis of CTAP findings, nodules were categorized as group A (showing almost the same portal venous supply as the surrounding liver), group B (showing decreased portal venous supply) or group C (showing partially absent portal venous supply); on the basis of CTHA findings, nodules were categorized as group I (showing almost the same arterial supply as the liver), group II (showing decreased arterial supply), or group III (showing partially increased arterial supply). RESULTS: Progression to classic HCC was observed in 29.4% of group A nodules, 53.9% of group B nodules, and 87.9% of group C nodules within 1,000 days; in 58.6% of group I nodules, 12.9% of group II nodules, and 92.2% of group III nodules within 730 days; and in 0% of nodules in group A and I, 28% of nodules in group B and/or II, and 88.7% of nodules in group C and/or III within 730 days. CONCLUSION: Evaluation of intranodular blood supply was valuable in predicting the prognosis in borderline lesions, except when only arterial blood supply was evaluated.     

Straight line sign: appearance and significance during CT portography

The computed tomographic (CT) angiograms of 44 patients who were being evaluated for possible hepatic surgery were studied. All patients were imaged with CT arterial portography (CTAP), delayed CT of the liver, and magnetic resonance (MR) imaging. All CTAP studies were evaluated for a "straight line," a linear variation in contrast within the liver. Sixteen patients (36%) demonstrated the straight line sign. All 16 had a mass at the proximal portion of the defect. Nine of 16 had defects that clearly correlated with portal venous distribution seen at limited digital angiography. Fourteen of the 16 patients showed loss of the straight line sign at delayed CT and/or MR imaging of the liver. These defects are thought to be due to vascular obstruction. The straight line sign will probably be seen more frequently as CTAP is more commonly used. Recognition of the sign is important in the evaluation of primary liver carcinomas, since it signifies that the tumor may be inoperable. Also, if metastatic disease is present, it alerts the surgeon to the proximity of the portal vein to the neoplasm.     

Hepatic arterioportal shunts not directly related to hepatocellular carcinoma: findings on CT during hepatic arteriography, CT arterial portography and dual phase spiral CT

AIM: To evaluate findings of arterioportal shunts not directly related to hepatocellular carcinoma (HCC) which were seen within third-order portal branches on computed tomography (CT) during hepatic arteriography (CTHA), arterial portography (CTAP), and dual phase spiral CT.MATERIALS AND METHODS: At CTHA in 112 patients, we examined third-order portal vein branches to find arterioportal shunts not directly related to HCC. Six cases were found. We evaluated the findings of these shunts on CTHA and investigated whether CTAP (n = 6) and dual phase spiral CT (n = 5) showed perfusion defects in the corresponding areas on arterioportal shunts. RESULTS: Five of six cases showed abrupt visualization of portal branches without visualization of the proximal portion of CTHA. Five of six cases showed no perfusion defect on CTAP and no hyperattenuating area on CTHA. Four of five cases showed no hyperattenuating area on hepatic arterial phase spiral CT. CONCLUSION: Arterioportal shunts not directly related to HCC and occuring within third-order portal branches mainly showed abrupt visualization of portal branches on CTHA. These occurred frequently without perfusion defects on CTAP and without a hyperattenuating area on CTHA and hepatic arterial phase spiral CT.Park, C. M. (2000). Clinical Radiology55, 465-470.     

Adenomatous hyperplasia with unusual imaging findings at combined helical CT hepatic arteriography and CT during arterial portography

We examined a patient with a hepatocellular carcinoma and multiple adenomatous hyperplasias in the cirrhotic liver. Helical CT hepatic arteriography (CTA) showed the adenomatous hyperplasias as areas of discrete hypoattenuation, and the combined CT during arterial portography (CTAP) showed corresponding areas of subtle hyperattenuation. Such imaging findings at combined CTA and CTAP were seen in only one patient in a series of more than 80 patients in whom we performed angiographically-assisted CT. We demonstrate these unusual imaging findings of adenomatous hyperplasia in the report.     

Dysplastic nodules in liver cirrhosis: evaluation of hemodynamics with CT during arterial portography and CT hepatic arteriography

PURPOSE: To evaluate the portal and arterial blood supplies to dysplastic nodules in the cirrhotic liver with computed tomography (CT) during arterial portography (CTAP) and CT hepatic arteriography (CTHA). MATERIALS AND METHODS: Nineteen histopathologically proved low-grade dysplastic nodules and 13 high-grade dysplastic nodules in 17 patients with liver cirrhosis were evaluated with CTAP and CTHA for the presence of portal and arterial blood supplies to the nodules. The nodules ranged from 0.4 to 4.5 cm in diameter (mean, 1.6 cm). RESULTS: The portal supply was present in 14 of the 19 (74%) low-grade dysplastic nodules and in seven of the 13 (54%) high-grade dysplastic nodules. The hepatic arterial supply was increased in four of the 19 (21%) low-grade dysplastic nodules, present in nine (47%), and absent in six (32%). The arterial supply was increased in four of the 13 (31%) high-grade dysplastic nodules, present in four (31%), and absent in five (38%). CONCLUSION: The portal and arterial supplies to the low- and high-grade dysplastic nodules were variable and inconsistent. Therefore, it is difficult to detect and characterize the dysplastic nodules on the radiologic images on the basis of the blood supply.     

Lower prevalence of non-tumoral perfusion defects in left hepatic lobe during CT arterial portography with splenic artery injection

OBJECTIVE: To determine whether there is a difference in the prevalence of non-tumoral perfusion defects (NTPD) in left hepatic lobe during CT arterial portography (CTAP) through splenic (SA) and superior mesenteric artery (SMA) injection. METHODS AND PATIENTS: For the preoperative evaluation, 59 patients (20 females, 39 males) who either have colorectal carcinoma metastasis (n: 42) or hepatocellular carcinoma (n: 17) underwent CTAP examination. Patients were divided into two groups (SA and SMA) according to the injection artery. The presence and type of NTPD in the left hepatic lobe were determined and compared. RESULTS: There were significant differences in peripherally located wedge shaped, perihilar-periligamentous and pericholecystic NTPD, but no significant difference was found in lobar/segmental defects between the groups. CONCLUSIONS: Our study demonstrated lower prevalence of NTPD in the left hepatic lobe in CTAPs performed through SA injection and we think that this could be explained by the streamlining of portal blood flow.     

CT during arterial portography

CT during arterial portography (CTAP) is based on portal enhancement of the liver by infusion of contrast material through the superior mesenteric or splenic artery. This technique provides high degrees of enhancement of the portal vein and intrahepatic vessels, allowing reliable segmental localisation of tumours and accurate assessment of relationships between tumours and intrahepatic vessels. Because of its invasiveness, CTAP must be limited to patients for whom non-invasive preoperative imaging suggests resectable tumour. In the majority of cases, CTAP is performed in patients with hepatic metastases from colorectal cancer, but other types of hepatic tumour (either primary or secondary) and pancreatic tumour may be an indication for CTAP. Visualisation of non-tumorous perfusion defects is a limitation of this technique, but such defects have been well described and have characteristic locations and appearance. In difficult cases, correlation with sonographic, CT and MRI findings helps characterise portal perfusion defects. CTAP is the most sensitive technique for the detection of intrahepatic tumours, and the recent use of spiral technology shows promise in the performance of CTAP. CTAP data can be viewed as multiplanar and three-dimensional reconstructions that allow preoperative planning of the extent of resection and determination of the volume of the remaining liver after resection.     

Nontumorous Perfusion Abnormalities of Liver Parenchyma Adjacent to the Falciform Ligament As Revealed by Angiographic Helical Ct and Angiography

Purpose: To investigate nontumorous abnormalities in the liver around the falciform ligament as revealed by arteriography and helical CT arterial portography (CTAP) and helical CT during hepatic arteriography (CTHA).Material and Methods: One hundred and seventeen patients simultaneously underwent hepatic arteriography and CTAP and CTHA of the common hepatic artery. The number, size, and shape of nontumorous defects of portal perfusion in the liver adjacent to the falciform ligament on CTAP as well as the nontumorous contrast enhancement in the same area on CTHA were determined. In 1 case, in which nontumorous enhancement was observed on CTHA, selective arteriography from the gastric arteries was performed.Results: On CTAP a nontumorous area of decreased portal perfusion of the liver around the falciform ligament was detected in 18 (15.4%) of the 117 patients, while nontumorous enhancement on CTHA was seen in 7 (6.0%). In 4 patients, both of these nontumorous abnormalities were observed. In the patient undergoing selective gastric arteriography, nonportal venous inflow to the liver in the direction to the liver adjacent to the falciform ligament was seen.Conclusion: One cause of nontumorous vascular abnormalities adjacent to the falciform ligament as shown on angiographic helical CT is aberrant gastric venous inflow to this region.     

Benign and malignant nodules in cirrhotic livers: distinction based on blood supply.

The blood supplies of nodular lesions associated with liver cirrhosis were analyzed in vivo with various imaging modalities. The portal blood supply was evaluated with computed tomography (CT) during arterial portography (CTAP); the arterial blood supply was evaluated with hepatic angiography, CT angiography, CT following intraarterial injection of iodized oil, or ultrasound following intraarterial injection of carbon dioxide microbubbles. A total of 84 surgically confirmed hepatocellular carcinomas (HCCs) (less than or equal to 3 cm) and 25 areas of adenomatous hyperplasia (AH) were included in the study. At CTAP, a portal blood supply was seen in 96% of cases of AH and only 6% of HCCs (chi 2, P less than .005). In contrast, an arterial supply greater than that of the surrounding liver was verified in 94% of the HCCs and only 4% of the cases of AH (chi 2, P less than .005). The blood supply of areas of AH with atypical hepatocytes and the blood supply of well-differentiated HCCs (Edmondson grade 1) tended to be intermediate between that of AH without atypia and that of HCC that was Edmondson and Steiner grade 2 or greater. Evaluation of the blood supply of the nodular lesions associated with liver cirrhosis is considered to be useful in the differential diagnosis and treatment of early-stage HCC.     

Detection of focal hepatic masses: prospective evaluation with CT, delayed CT, CT during arterial portography, and MR imaging

The sensitivities of contrast medium-enhanced computed tomography (CT), delayed CT (DCT), CT during arterial portography (CTAP), and magnetic resonance (MR) imaging for detecting focal liver lesions were prospectively evaluated in eight patients who subsequently underwent hepatic lobectomy or transplantation. Pathologic evaluation of the resected liver specimens demonstrated 37 lesions. The sensitivities were 81% (30 of 37 lesions) for CTAP, 57% (21 of 37 lesions) for MR imaging, 52% (12 of 23 lesions) for DCT, and 38% (14 of 37 lesions) for contrast-enhanced CT. The difference between the sensitivity of CTAP and the sensitivities of the other imaging tests was statistically significant (P less than .004). Of the lesions smaller than 1 cm in diameter, CTAP depicted 61% (11 of 18 lesions), MR imaging 17% (three of 18 lesions), CT 0% (zero of 18 lesions), and DCT 0% (zero of nine lesions). It is concluded that for preoperative detection of focal hepatic masses, CTAP is the most accurate technique available to most radiologists. Patients with primary or secondary hepatic neoplasms who are being considered for hepatic resection should undergo CTAP as part of their preoperative examination.     

CT during arterial portography: effects of precontrast injection of prostaglandin E1 into the superior mesenteric artery

Prostaglandin E1 (PGE1) is a vasodilator that increases portal venous flow. Hepatic CT during arterial portography (CTAP) was performed in 42 patients with and without PGE1 to compare peak hepatic enhancement and nontumorous abnormalities. Although no significant differences in peak hepatic enhancement were observed (71 +/- 12 HU for CTAP with PGE1; 74 +/- 34 HU for CTAP without PGE1), the number of nontumorous abnormalities for CTAP with PGE1 (n = 11) was significantly lower than that for CTAP without PGE1 (n = 24) (p < 0.01, Wilcoxon signed rank test). CTAP combined with PGE1 therefore represents a useful method to study lesions of the liver, as the number of nontumorous abnormalities observed is significantly reduced and liver parenchyma can be scanned more evenly.     

Improved diagnosis of hepatic perfusion disorders: value of hepatic arterial phase imaging during helical CT.

The liver has a unique dual blood supply, which makes helical computed tomography (CT) a highly suitable technique for hepatic imaging. Helical CT allows single breath-hold scanning without motion artifacts. Because of rapid image acquisition, two-phase (hepatic arterial phase and portal venous phase) evaluation of the hepatic parenchyma is possible, improving tumor detection and tumor characterization in a single CT study. The arterial and portal venous supplies to the liver are not independent systems. There are several communications between the vessels, including transsinusoidal, transvasal, and transplexal routes. When vascular compromise occurs, there are often changes in the volume of blood flow in individual vessels and even in the direction of blood flow. These perfusion disorders can be detected with helical CT and are generally seen as an area of high attenuation on hepatic arterial phase images that returns to normal on portal venous phase images; this finding reflects increased arterial blood flow and arterioportal shunting in most cases. Familiarity with the helical CT appearances of these perfusion disorders will result in more accurate diagnosis. By recognizing these perfusion disorders, false-positive diagnosis (hypervascular tumors) or overestimation of the size of liver tumors (eg, hepatocellular carcinoma) can be avoided.     

Computed tomography during arterial portography prior to transcatheter arterial therapy in hepatocellular carcinoma with marked portal extension: four case reports.

Computed tomography during arterial portography (CTAP) is acknowledge as a valuable preoperative method for the detection of small intrahepatic lesions in patients with liver neoplasm. Four patients with hepatocellular carcinoma (HCC) with marked portal extension are presented. Evaluation of intrahepatic portal blood flow was achieved more accurately by CTAP than by conventional arterial portography. CTAP also plays an important role in patients with inoperable HCC, since portal extension is the most important prognostic factor of transcatheter arterial therapy.     

Dynamic CT scanning of the normal canine liver: interpretation of time density curves resulting from an intravenous bolus injection of contrast material

Seven adult male mongrel dogs were monitored by electromagnetic flow probes and string occluders around the hepatic artery and portal vein. Then, time density curves of the liver, aorta and portal vein were recorded using dynamic CT scanning following the bolus injection of contrast material into a peripheral vein (n = 7) and a mesenteric vein branch (n = 5). Information on total hepatic blood flow could not be obtained from the mesenteric vein injection. The hepatic time density curve could, however, be broken into its two components, hepatic arterial and portal venous flow contribution, by selective ligation of the hepatic artery or portal vein. It could be demonstrated that the arterial component of liver enhancement reached its peak at the end of the aortic wash-out of contrast material. Thus, the hepatic time-density curve could be broken in its two components by superimposing the aortic time density curve onto the hepatic curve. An attempt was made to estimate relative portal venous blood flow by using the slopes or the peaks of both components of the hepatic curve. Using the slopes of the hepatic curve resulted in a consistent underestimation of portal venous blood flow, whereas the peaks gave an estimate of portal venous flow with an accuracy within +/- 8%.