Metastatic nodules of hepatocellular carcinoma: detection with angiography, CT, and US

Accurate detection of intrahepatic metastases, or daughter nodules, of primary hepatocellular carcinoma is of crucial importance. Due to the introduction of infusion hepatic angiography, computed tomography (CT) after Lipiodol (iodized oil) infusion, and intraoperative ultrasound (US), tumors less than 10 mm in diameter are now frequently found. We compared the diagnostic accuracy of these three modalities in the detection of nodules in 45 patients who had hepatocellular carcinoma (confirmed by biopsy). CT with Lipiodol was superior to hepatic angiography in demonstrating nodules when they were overlapped by the primary tumor or very small in size. Intraoperative US demonstrated nodules in four avascular or hypovascular hepatocellular carcinomas, which both hepatic angiography and CT failed to demonstrate. In cases associated with severe liver cirrhosis, differentiation of small nodules from regenerating cirrhotic nodules was sometimes difficult with intraoperative US. The combined use of these three modalities is indispensable for the accurate detection of small nodules of metastatic hepatocellular carcinoma.     

Lipiodol UltraFluid in the imaging diagnosis of hepatocarcinoma with cirrhosis

Fifty patients with HCC associated with hepatic cirrhosis underwent intra-arterial injection of Lipiodol UltraFluid (LUF) during diagnostic DSA of liver parenchyma, 42 of them for a complete chemotherapeutic treatment, 8 for an isolated diagnostic control. LUF is known to be specifically captured by HCC neoplastic tissue, with long-term persistence in the lesion if injected in the arterial hepatic tree; this is not the case with other focal hepatic masses. Therefore LUF opacification can be used to demonstrate small daughter tumors not shown by CT or US in cases with evidence of HCC, or to diagnosis HCC in clinically positive patients with no evidence of tumor at non-invasive screening. In our series of patients, accumulation of LUF in the HCC was observed in 100% of the cases, with no false negatives. Two false positives (4%) were observed, due to CT being performed too early (it should be performed not sooner than 10 days after the injection). Overall DSA accuracy was 78%, with 22% false negatives. In 14% of the cases DSA was positive for HCC in patients with aspecific noninvasive screening. CT, performed 10 days after LUF injection, demonstrated HCC daughter tumors not depicted by US, conventional CT, and angiography, in 34% of the cases, and in 9% of the patients only CT/LUF was able to show HCC in clinically positive cases with no evidence of tumor on other imaging techniques. Specificity, sensitivity and over-all accuracy were thus 100% in our series; LUF was well tolerated by the patients, and no technical complications were observed. In our opinion, the diagnostic DSA and CT/LUF is justified only for the typification of suspected focal nodules unsuitable for biopsy: in other instances, especially in case of HCC with positive biopsy/clinical findings and focal nodular mass, the technique should be directly employed as a therapeutic approach, with the injection of lipiodolized agents to treat both primary and daughter nodules after surgery in operable patients, and to begin chemoembolization treatment in patients with intrahepatic polyfocal diffusion. DSA and LUF are therefore of primary importance in the diagnosis and therapeutic flow-chart of HCC associated with hepatic cirrhosis.     

原发性肝癌的电子束CT增强特征

目的 :探讨原发性肝癌的电子束CT增强特征。材料和方法 :3 2例原发性肝癌行 3 5例次平扫和双期或三期增强扫描。肝动脉期扫描时间约为 2 0～ 2 5s ,门静脉期约为 40～ 5 0s ,平衡期扫描延长至 10 0s甚至 5～ 10min。把肝癌的增强分为 7种方式分析肿瘤增强特征。结果 :共检出 86个肿块和结节 ,动脉期能显示肿瘤的血管、动脉门静脉瘘、假包膜血供、门静脉癌栓。≤ 3 0cm结节动脉期 61%呈均匀高密度增强 ,13个表现为均匀或不均匀等密度 ,6个为低密度。门静脉期低密度肝癌结节 2 8个 (65 % ) ,均匀等密度结节 13个 ,少数表现为不均匀等密度和高密度。 >3 0cm肿块动脉期65 %表现为均匀或不均匀高密度 ,7个为不均匀等密度 ,6个为低密度。在门静脉期肿瘤主要表现为不均匀低密度 79%(2 7/3 4) ,5个表现为不均匀等密度 ,2个为均匀等密度 ,无 1例高密度。无论肿瘤大小平衡期呈等、低密度。结论 :EBCT显示肿瘤的血供特征以及门静脉累及 ,是肝癌和临床怀疑肝癌的重要检查技术     

Detection of hepatocellular carcinoma: comparison of CT during arterial portography with CT after intraarterial injection of iodized oil

Fourteen patients with hepatocellular carcinoma (HCC) were examined with computed tomography (CT) during arterial portography (CTAP) and with CT after intraarterial injection of iodized oil. The detectability of main lesions and associated daughter nodules or intrahepatic metastases was assessed. Hepatic resection was subsequently performed in all 14 patients. The results of the imaging studies were compared with the surgical and pathologic findings by means of a lesion-by-lesion analysis. A total of 34 masses were identified in the resected specimens: 18 main tumor masses and 16 intrahepatic metastases. For CTAP, the detection rate of main tumors was 94%; for iodized-oil CT, 82%. However, the daughter-nodule detection rates for both techniques were poor-only 38% detected for CTAP and 50% for iodized-oil CT. Although these two techniques remain important preoperative imaging methods in patients with HCC, the results of this study suggest that small daughter nodules (less than 5 mm in diameter) may go undetected with both techniques.     

Re-evaluation of detectability of liver metastases by contrast-enhanced CT: added value of hepatic arterial phase imaging

Purpose

We compared the detectability of liver metastases on 2- and 3-phase images using robust statistical methods. Nine radiologists evaluated unenhanced CT plus portal venous phase (2-phase) images and 2-phase plus hepatic arterial phase (HAP) (3-phase) images.

Materials and methods

Our study included 54 patients with primary malignant tumors who underwent 3-phase hepatic dynamic CT more than twice to screen for liver metastases; 24 had 1–6 liver metastases measuring 4–27 mm in diameter (median 13 mm). The other 30 had no metastases. Nine board-certified radiologists participated in our observer performance study. They specified the location of the metastatic lesions and rated the probability of metastatic nodules on 2-phase images acquired with and without HAP imaging. We used jackknife alternative free-response receiver operating characteristic (JAFROC) analysis to compare their performances.

Results

For all radiologists the area under the curve without and with HAP imaging was 0.86 and 0.88, respectively; the difference was significant (p = 0.04). For metastases smaller than 10 mm the averaged lesion localization fraction without and with HAP imaging was 0.17 and 0.26 (p < 0.01).

Conclusion

Adding HAP to 2-phase imaging improved the detectability of liver metastases, especially of lesions smaller than 10 mm.     

Liver metastases from colorectal cancers: detection with CT during arterial portography

A total of 45 metastases to the liver from colorectal cancer were resected in 22 patients. The detectability of these lesions with the following modalities was determined: real-time ultrasound (US), computed tomography (CT), selective celiac arteriography (SCA), infusion hepatic angiography (IHA), CT during arterial portography (CTAP), and CT following intraarterial injection of iodized poppyseed oil (Lipiodol). The total detection rate (sensitivity) was 58% for US, 63% for CT, 27% for SCA, 50% for IHA, 84% for CTAP, and 38% for CT with iodized oil. Ten of 18 lesions less than 15 mm in largest diameter were demonstrated preoperatively by CTAP only. CTAP is useful in clarifying the locations of the lesions in the liver and should always be performed before liver metastases from colorectal cancer are resected.     

肝硬化基础上肝癌肝血流变化功能CT灌注成像研究

目的对正常肝实质、肝硬化和肝硬化基础上肝癌患者的64层螺旋CT灌注成像进行分析,评价多层螺旋CT灌注成像对肝硬化基础上肝癌肝血流变化的诊断价值。资料与方法无肝脏疾病的30例作为对照组。实验组包括49例肝硬化疾病患者,其中27例确诊为原发性肝癌(HCC)。所有研究对象知情同意后,选择癌灶中心层面或肝门层面行CT灌注扫描,采用低剂量扫描:120 kV,60 mA,扫描范围为40 mm。以4～5 ml/s流率,按照1.0ml/kg体重用量静脉团注对比剂。在注入对比剂5 s后行50 s连续的扫描,360°旋转/s,5 mm层厚进行图像重组,矩阵大小512×512像素。利用去卷积数学模型获得与肝血流变化相关的灌注参数值:肝血流量(HBF),肝血容量(HBV),肝动脉灌注分数(HAF),肝动脉灌注量(HAP),门静脉灌注量(HPP)。对不同的感兴趣区进行三次灌注参数测量后取平均值进行灌注结果分析。感兴趣区包括:对照组的正常肝实质、癌灶边缘区、癌灶周围的肝实质和无癌灶的肝硬化肝实质。结果与对照组灌注参数比较,癌周围肝实质的HBF、HAP、HPP、HBV及癌灶边缘区的HBF、HAP、HPP有统计学差异(P<0.05)。与对照组相对应灌注参数比较,癌周的HAP、HPP及对照组的HBF、HAP、HPP有统计学差异(P<0.05)。与癌边缘区HAF对比,癌灶周围肝实质、对照组和无癌灶的肝硬化组均有统计学差异(P<0.05)。对照组和无癌灶的肝硬化组间灌注参数无明显差异(P>0.05)。结论 CT灌注成像能很好地反映肝硬化基础上肝癌的肝血流变化信息,为肝血流动力学变化的影像研究提供新的方法。     

Arterial blood supply to the posterior aspect of segment IV of the liver from the caudate branch: demonstration at CT after iodized oil injection

PURPOSE: To retrospectively evaluate the arterial blood supply to the posterior aspect of segment IV of the liver with computed tomography (CT) after transcatheter arterial chemoembolization (TACE) with iodized oil through the caudate arterial branch of the liver for treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Institutional review board approval and patient informed consent were not required for this retrospective study. Twenty-four patients (11 men and 13 women; mean age, 68 years) with HCC originating in the caudate lobe (n = 23) or posterior aspect of segment IV (n = 1) were selected. TACE of the caudate arterial branch was performed in all patients, including one patient with HCC in the posterior aspect of segment IV who underwent TACE of the caudate arterial branch after CT helped confirm that iodized oil was not distributed in the tumor after TACE of the medial segmental artery. The distribution of iodized oil in the posterior aspect of segment IV was analyzed with CT 1 week after TACE. The number and origin of all arteries supplying the caudate lobe and the number of arteries embolized were determined. RESULTS: Thirty-three caudate arterial branches were embolized. Twenty-nine branches were derived from the right hepatic artery and four were derived from the left hepatic artery. A single branch was seen in 17 patients, two branches were seen in five, and three branches were seen in two. Eight patients simultaneously underwent additional TACE of branches of the right hepatic artery (n = 6) or right inferior phrenic artery (n = 2). At CT, iodized oil was seen to be distributed entirely (n = 19) or partially (n = 5) in the caudate lobe. Distribution of iodized oil at the posterior aspect of segment IV was observed in 16 patients (67%), including 13 (54%) whose caudate arterial branches were derived entirely from the right hepatic artery. CONCLUSION: The results of this study suggest that the caudate arterial branch, which is mainly derived from the right hepatic artery, frequently supplies the posterior aspect of segment IV. This knowledge is important for managing HCC in the posterior aspect of segment IV by means of TACE.     

Iodized oil accumulation in hypervascular hepatocellular carcinoma after transcatheter arterial chemoembolization: comparison of imaging findings with CT during hepatic arteriography

PURPOSE: To compare the degree of tumor enhancement seen on computed tomography (CT) during hepatic arteriography (CT/HA) performed before transcatheter arterial chemoembolization (TACE) versus that determined based on the accumulation of iodized oil seen on CT images obtained after TACE in patients with hypervascular hepatocellular carcinoma (HCC) and evaluate the discrepancy in findings between the two imaging modalities (more or less oil accumulation after TACE compared with enhancement on CT/HA). MATERIALS AND METHODS: CT/HA, TACE, and iodized oil CT after TACE were performed in 69 patients with 83 hypervascular HCCs with use of an interventional CT system. The degree of contrast enhancement of the lesion on CT/HA and the iodized oil accumulation on unenhanced CT after TACE were compared. RESULTS: Among 83 HCCs, the degree of enhancement on CT/HA before TACE corresponded to the iodized oil accumulation on CT in 56 (67.5%). Fifteen of 83 HCCs (18%) showed incomplete or poor accumulation of iodized oil despite good enhancement on CT/HA images. Twelve of 83 HCCs (14.5%) showed moderate or complete accumulation of iodized oil despite poor or no enhancement on CT/HA images. In particular, in two patients with occluded portal veins, iodized oil did not accumulate in the tumor despite good visualization on CT/HA. CONCLUSIONS: Although iodized oil accumulation in hypervascular HCCs correlates with the degree of lesion enhancement on CT/HA in most cases, a discrepancy may occur in a substantial number of cases, which likely affects the prediction of therapeutic effects in hypervascular HCCs.     

Effect of stabilized iodized oil emulsion on experimentally induced hepatocellular carcinoma in rats

PURPOSE: Previous studies have shown that the use of Lipiodol UltraFluid (LUF) emulsified with water leads to an increase in the tumoral uptake of iodine I 131-labeled LUF and reduced pulmonary uptake. Although emulsions containing LUF are currently used for chemoembolization of hepatocellular carcinomas (HCCs), this approach is impossible with intraarterial radiation therapy (RT) because of the problems of radiation protection linked to instability of the emulsions. The aims of this study were to develop stabilized emulsions of radiolabeled LUF of different particle sizes and viscosities and to study its biodistribution in rats with HCC. MATERIALS AND METHODS: An emulsifier made of polyethylene glycol and hydrogenated castor oil was used to stabilize emulsions containing water and technetium Tc 99m-labeled Super Six Sulfur LUF. The various emulsions were injected in the hepatic arteries of rats with HCC. Twenty-four hours after injection, the rats were killed and the liver, tumor, and lungs were removed to perform ex-vivo gamma-counting to quantify tumoral, hepatic, and pulmonary uptake. RESULTS: Emulsions of oil in water and water in oil of different viscosities (0.68-1.06 Pa.S) and particle size distributions (21-45 mum) were prepared and kept stable for more than 24 hours. Whatever the type of emulsion, the observed effect on tumoral uptake was the opposite of that expected. Indeed, a decrease in tumoral activity was observed (P < .05 in three of five cases) and a tendency toward increased pulmonary activity was observed (P < .05 in two of five cases) rather than any significant decrease. CONCLUSIONS: This study made it possible to develop emulsions of radiolabeled iodized oil that remain stable for more than 24 hours. However, studies of biodistribution in rats with HCC failed to demonstrate any improvement in tumoral targeting, but rather showed a decrease in tumoral uptake that renders this approach impractical for intraarterial radiolabeled iodized oil RT as well as for intraarterial iodized oil chemoembolization. These results may possibly be explained by the use of an emulsifier containing lipophilic and hydrophilic components that modify the properties of LUF.     

高速多排螺旋CT与DSA对肝癌子灶检出的对比分析

目的　比较高速多排螺旋CT与DSA对肝癌子灶检出的敏感性 ,并研究肝癌子灶的高速多排螺旋CT的三期增强扫描影像特征。方法　对 11例肝癌伴子灶病人行高速多排螺旋CT三期薄层扫描。注射 80ml造影剂后延迟 2 5s后行动脉期扫描 ,延迟60s后行门静脉期扫描 ,12 0s后行延迟期扫描。CT扫描后 5d之内行DSA造影。结果　高速多排螺旋CT显示 40个子灶 ,其中 2 2个子灶≤ 1.0cm ,12个子灶在 1.0～ 2 .0cm之间 ,6个子灶 >2 .0cm。DSA显示 14个子灶 ,均 >1.0cm。CT平扫 3 4个子灶呈低密度 ,4个呈等密度 ;增强后动脉期 3 2个子灶强化 ,8个无强化 ;门静脉期 3 3个呈低密度 ,7个等密度。延迟期 3 9个呈低密度 ,1个呈等密度。结论　肝癌小子灶的发现率高速多排螺旋CT明显优于DSA ,尤其是检出 <1.0cm的子灶更具优势     

Hepatocellular adenoma: multiphasic CT and histopathologic findings in 25 patients

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

Hypervascular hepatocellular carcinomas: bolus tracking with a 40-detector CT scanner to time arterial phase imaging

PURPOSE: To evaluate prospectively bolus tracking to time hepatic arterial phase (HAP) imaging of hypervascular hepatocellular carcinomas (HCCs) with a 40-detector computed tomographic (CT) scanner. MATERIALS AND METHODS: This study received institutional review board approval; informed consent was obtained. The study included 192 patients (123 men, 69 women; mean age, 67.6 years) with known or suspected HCC who underwent dynamic CT, including HAP scanning; CT depicted 111 hypervascular HCCs in 72 patients. Scanning was performed with a 40-detector CT scanner, and bolus tracking was used to time the start of HAP imaging. Patients were randomly assigned to five protocols; HAP scanning was started at a specified interval after trigger threshold was reached: 9 seconds (protocol A), 12 seconds (protocol B), 15 seconds (protocol C), 18 seconds (protocol D), or 21 seconds (protocol E). Trigger threshold level was set at 100 HU above aortic baseline CT number. Enhancement values in the aorta and the tumor-liver contrast (TLC) were measured. Dunnett multiple comparisons were performed to compare enhancement values among the five protocols. RESULTS: Mean scanning time for the whole liver was 2.1 seconds. Mean enhancement value of the aorta in protocols A, B, C, D, and E were 284.3 HU +/- 54.7, 293.8 HU +/- 51.0, 308.7 HU +/- 55.9, 291.5 HU +/- 42.2, and 235.5 HU +/- 51.2, respectively. Aortic enhancement was significantly lower in protocol E than in protocol A (P < .01); there was no significant difference between protocols A and B, A and C, and A and D. Mean TLCs in protocols A, B, C, D, and E were 23.4 HU +/- 7.6, 35.5 HU +/- 14.0, 36.2 HU +/- 6.8, 47.2 HU +/- 19.2, and 35.1 HU +/- 15.8, respectively. A significant difference was found only between protocols A and D (P < .01). CONCLUSION: Peak TLC during the HAP occurred 18 seconds after triggering.     

Hepatocellular carcinoma: role of unenhanced and delayed phase multi-detector row helical CT in patients with cirrhosis

PURPOSE: To determine, by using multi-detector row helical computed tomography (CT), the added value of obtaining unenhanced and delayed phase scans in addition to biphasic (hepatic arterial and portal venous phases) scans in the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis. MATERIALS AND METHODS: Local ethical committee approval and patient consent were obtained. One hundred ninety-five patients (129 men, 66 women; mean age, 61 years; age range, 39-78 years) with 250 HCCs underwent multi-detector row helical CT of the liver. A quadruple-phase protocol that included unenhanced, hepatic arterial, portal venous, and delayed phases was performed. Analysis of images from hepatic arterial and portal venous phases combined, hepatic arterial and portal venous phases with the unenhanced phase, hepatic arterial and portal venous phases with the delayed phase, and all phases combined was performed separately by three independent radiologists. Relative sensitivity, positive predictive value, and area under the receiver operating characteristic curve (A(z)) were calculated for each reading session. RESULTS: Mean sensitivity and positive predictive values, respectively, for HCC detection were 88.8% (666 of 750 readings) and 97.8% (666 of 681 readings) for the combined hepatic arterial and portal venous phases, 89.2% (669 of 750 readings) and 97.8% (669 of 684 readings) for hepatic arterial and portal venous phases with the unenhanced phase, 92.8% (696 of 750 readings) and 97.3% (696 of 715 readings) for hepatic arterial and portal venous phases with the delayed phase, and 92.8% (696 of 750 readings) and 97.3% (696 of 715 readings) for all four phases combined. The reading sessions in which delayed phase images were available for interpretation showed significantly (P < .05) superior sensitivity and A(z) values. CONCLUSION: Unenhanced phase images are not effective for HCC detection. Because of the significant increase in HCC detection, a delayed phase can be a useful adjunct to biphasic CT in patients at risk for developing HCC.     

CT features of an intraductal polypoid mass: Differentiation between hepatocellular carcinoma with bile duct tumor invasion and intraductal papillary cholangiocarcinoma

OBJECTIVE: To determine the CT features capable of differentiating hepatocellular carcinoma (HCC) with bile duct tumor invasion (BDTI) from intraductal cholangiocarcinoma (IDCC). METHODS: 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, the enhancement pattern of intraductal lesions, degree of ductal dilatation, presence of downstream ductal dilatation and ductal wall thickening, presence of parenchymal mass and its size, continuity of parenchymal mass with 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 Fisher exact test or Mann-Whitney test. RESULTS: Significant variables that helped differentiating HCC with BDTI from IDCC included the presence of parenchymal mass, liver cirrhosis, and the 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 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 portal venous phase (PVP) between the 2 conditions (P = 0.003). CONCLUSIONS: Several objective and subjective multiphasic CT findings may help differentiating HCC with BDTI from IDCC.     

Outcome of hypovascular hepatic nodules revealing no gadoxetic acid uptake in patients with chronic liver disease

Purpose:

To elucidate the natural history of hypovascular nodules that appear hypointense on hepatocyte‐phase gadoxetic acid‐enhanced MR images by focusing on hypervascularization over time.

Materials and Methods:

In this study, 135 hypovascular nodules revealing no gadoxetic acid uptake in 53 patients were examined. All nodules were retrospectively examined using serial follow‐up computed tomography (CT) and MRI examinations until hypervascularity was observed on arterial‐phase dynamic CT or gadoxetic acid‐enhanced MR images, or on CT during hepatic arteriography. Logistic regression analysis was used to investigate the association between hypervascularization and MR findings including a presence of fat assessed by a signal drop on opposed‐phase T1‐weighted images.

Results:

Of the 135 nodules, 16 underwent hypervascularization. The size of the nodules and the presence of fat in the nodules were independent indicators of hypervascularization. The 1‐year cumulative risk of hypervascularization was 15.6%. This risk was significantly increased in the case of nodules >10 mm (37.6%, P < 0.01) and fat‐containing nodules (26.5%, P < 0.01).

Conclusion:

Hypovascular nodules that appear hypointense on hepatocyte‐phase gadoxetic acid‐enhanced MR images may progress to conventional hypervascular hepatocellular carcinoma. Nodules more than 10 mm in diameter and containing fat are at high risk for developing hypervascularization. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Pretransplantation diagnosis and staging of hepatocellular carcinoma in patients with cirrhosis: value of dual-phase helical CT

OBJECTIVE: The objective of our study was to prospectively evaluate the results of helical CT in the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis undergoing orthotopic liver transplantation. SUBJECTS AND METHODS. Eighty-five patients with cirrhosis were studied preoperatively with biphasic helical CT. Arterial, portal, and equilibrium phase images were obtained after injection of 170 mL of contrast material at 5 mL/sec. The prospective CT interpretation was compared with pathologic results on a lesion-by-lesion basis. RESULTS: Pathologic examination found 85 cases of HCC in 51 patients. Helical CT enabled a correct diagnosis of HCC in 67 of 85 lesions for a sensitivity of 78.8%. HCC nodules were hypervascular in the arterial phase and hypovascular in the equilibrium phase in 63.5% (54/85) of patients. The false-negative rate was 21% (n = 18), and the positive predictive value was 88%. We had nine false-positive findings (11.8%) related to hemangiomas, transient hepatic attenuation differences, and regenerative nodules. Helical CT detected 61% (23/38) of lesions smaller than 2 cm and 93.6% (44/47) of lesions 2 cm or larger. CONCLUSION: Helical CT is a useful preoperative imaging technique in cirrhotic patients who are candidates for orthotopic liver transplantation, although it is relatively insensitive for detection of small lesions (< 2 cm).     

Evaluation of posttreatment response of hepatocellular carcinoma with contrast-enhanced coded phase-inversion harmonic US: comparison with dynamic CT.

PURPOSE: To assess the reliability of contrast material-enhanced real-time gray-scale ultrasonography (US) in evaluating posttreatment response of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty HCC nodules were examined with contrast-enhanced coded phase-inversion harmonic US before and after treatment. Intratumoral vascularity was assessed with continuous imaging in the early arterial phase and with interval-delay scanning to depict tumor parenchymal flow during the blood pool phase. Vascular findings at US were compared with those at dynamic computed tomography (CT). RESULTS: In 50 HCC nodules before treatment, positive enhancement of tumor vessels and tumor parenchymal flow (stain) were observed in 47 (94%) and 46 (92%), respectively. Either tumor vessel or stain was visualized with coded harmonic US in 49 of 50 nodules. Eighty-one coded harmonic US studies were performed in 49 posttreatment HCC nodules. Compared with dynamic CT, the sensitivity, specificity, and accuracy of coded harmonic US in helping to detect positive enhancement in pretreatment HCC were 98% (49 of 50), 100% (50 of 50), and 98% (49 of 50), respectively. After treatment, positive enhancement of tumor vascularity was observed in 39 (48%) of 81 posttreatment studies, and no enhancement was observed in others (52%). Coded harmonic US demonstrated partial and no enhancement of tumor vascularity in four and one nodule, respectively; after transcatheter arterial embolization with iodized oil, evaluation of tumor vascularity with dynamic CT was difficult because of the presence of oil. CONCLUSION: With enhancement, coded harmonic US depicted tumor vascularity by showing tumor vessels in a real-time fashion at continuous imaging and tumor parenchymal flow at interval-delay scanning.     

Detection of hepatocellular carcinoma: comparison of dynamic three-phase computed tomography images and four-phase computed tomography images using multidetector row helical computed tomography

PURPOSE: The purpose of our study was to assess the value of additional early arterial phase computed tomography (CT) imaging in the detection of hepatocellular carcinoma (HCC) by comparing three-phase and four-phase imaging by using multidetector row helical CT. METHODS: Twenty-five patients with 33 HCCs underwent four-phase helical CT imaging. The diagnosis was established by pathologic examination after surgical resection in 19 patients and by biopsy in six. Four-phase CT imaging comprises early arterial, late arterial, portal venous, and delayed phase imaging obtained 25 seconds, 45 seconds, 75 seconds, and 180 seconds after the start of contrast material injection using multidetector row helical CT. Three-phase CT images (late arterial, portal venous, and delayed phase) and four-phase CT images (early arterial, late arterial, portal venous, and delayed phase) were interpreted independently for the detection of HCC by three blinded observers on a segment-by-segment basis. Sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (Az) for three-phase CT images and four-phase CT images were calculated. The enhancement pattern of HCC was analyzed on early arterial and late arterial phase imaging. RESULTS: The mean sensitivity of three- and four-phase CT images was 94% and 93%, respectively. The differences between sensitivities were not statistically significant (all p > 0.05). The mean specificities of three- and four-phase CT images were 99% and 98%, respectively. The differences between the specificities were not statistically significantly (all p > 0.05). Neither were the mean areas under the ROC curve for four-phase CT images (Az = 0.976) and three-phase CT images (Az = 0.971) statistically significant (p > 0.05). On early arterial phase imaging, 16 HCCs were hyperattenuating and 17 HCCs were isoattenuating. On late arterial phase imaging, 24 HCCs were hyperattenuating and nine HCCs were isoattenuating. CONCLUSIONS: Additional early arterial phase imaging did not improve the detection of HCC compared with three-phase CT images, including late arterial, portal venous, and delayed phase imaging.     

Optimizing scan delays of fixed duration contrast injection in contrast-enhanced biphasic multidetector-row CT for the liver and the detection of hypervascular hepatocellular carcinoma

OBJECTIVE: To determine the optimal scan delay required for fixed duration contrast injection in contrast-enhanced biphasic multidetector-row CT for the liver and the detection of hypervascular hepatocellular carcinoma (HCC). METHODS: CT images (2.5-mm collimation, 5-mm thickness with no intersectional gap) were obtained after an intravenous bolus injection of 2 mL/kg of nonionic iodine contrast material (300 mg I/mL) for a fixed 30-second injection in 206 patients, who were prospectively randomized into four groups, for which scans were initiated at -5, 15, and 35 seconds; at 0, 20, and 40 seconds; at 5, 25, and 45 seconds; or at 10, 30, and 50 seconds for the first (acquisition time: 4.3 seconds), second (4.3 seconds), and third (9.1 seconds) phases, respectively, after the completion of contrast injection. Mean CT values (HU) of the abdominal aorta, spleen, main portal veins, liver parenchyma, and hepatic veins were measured. Increases in CT values between pre- and post-contrast CTs (DeltaHU) for the organs, and spleen-to-liver and HCC-to-liver contrast differences (deltaHU) were assessed. RESULTS: Abdominal aorta reached 273-301 DeltaHU at -5 to 10 seconds with a peak (301 DeltaHU) at 5 seconds. Spleen peaked (115 DeltaHU) at 10 seconds. Liver parenchyma were enhanced weakly (11-34 DeltaHU) at -5 to 10 seconds, exceeded 50 DeltaHU at 20 seconds, peaked (61 DeltaHU) at 30 seconds, and then plateaued (54-58 DeltaHU) at 35-50 seconds. Hepatic veins were enhanced weakly (14-37 DeltaHU) at -5 to 10 seconds, and reached 67 DeltaHU at 15 seconds. Spleen-to-liver (65-69 deltaHU) and HCC-to-liver (31-34 deltaHU) contrast differences were highest at 5-10 seconds. Qualitative results corresponded well with quantitative results. CONCLUSIONS: For the detection of hypervascular HCCs, the optimal scan delay after a 30-second contrast injection of the hepatic arterial phase, was found to range from 5 to 10 seconds, and that of the portal venous phase was 35 seconds or somewhat longer.