Therapeutic ethanol injection of hepatocellular carcinomas undetectable by angiography and lipiodol computed tomography

Seven smaller than 2 cm in diameter hepatocellular carcinomas (HCC) undetectable by hepatic arteriography and computed tomography (CT) after intraarterial injection of iodized oil (Lipiodol CT) were diagnosed by ultrasonography-guided fine-needle biopsy in 6 patients. All lesions were treated by percutaneous ethanol injection (PEI) in 1–3 weekly intervals. No recurrences have been demonstrated after 7–15 months. The treatment of HCCs undetectable by angiography and Lipiodol CT presents a problem as transcatheter arterial embolization is considered ineffective due to, poor vascularity. PEI appears to be an excellent treatment for these small HCCs.     

Prediction of viable tumor in hepatocellular carcinoma treated with transcatheter arterial chemoembolization: usefulness of attenuation value measurement at quadruple-phase helical computed tomography

OBJECTIVE: To assess the usefulness of attenuation value measurement at quadruple-phase helical computed tomography (CT) for predicting viable tumor in hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolization (TACE). METHODS: Thirty-two patients who had an iodized-oil defect area (IODA) in HCCs treated with TACE were included in our study; these patients were divided into group 1 (n = 21) with viable tumor and group 2 (n = 11) without viable tumor in the IODA. All the patients underwent quadruple-phase helical CT (unenhanced and contrast-enhanced hepatic arterial, portal venous and equilibrium phases) before and after TACE. The attenuation difference of the IODA between unenhanced and each contrast-enhanced phase was measured, and the attenuation degree of the IODA relative to the hepatic parenchyma were subjectively assessed and then compared between the 2 groups. RESULTS: The mean attenuation differences of the IODAs were 28.8, 35.9, and 25.6 Hounsfield unit (HU) in group 1 and 0.4, 1.9, and 2.0 HU in group 2 at the hepatic arterial, portal venous, and equilibrium phases, respectively, with statistically significant difference for each phase (P < 0.05). The IODAs had attenuation difference of more than 20 HU on at least 1 contrast-enhanced phase in group 1 and less than 5 HU at all contrast-enhanced phases in group 2. For the attenuation degree of IODAs relative to the hepatic parenchyma, 12 patients (57%) showed hyperattenuation at the hepatic arterial phase, and remaining nine (43%) at the hepatic arterial phase and all patients at the portal venous and equilibrium phases showed isoattenuation or hypoattenuation in group 1. In group 2, all the patients showed hypoattenuation at all the 3 phases. CONCLUSIONS: The presence of viable tumor of the IODA in HCC treated with TACE can be precisely assessed by measuring attenuation values, strongly suggesting viable tumor when the attenuation difference is more than 20 HU on at least 1 contrast-enhanced phase at quadruple-phase helical CT.     

胆囊癌的多层螺旋CT表现

目的探讨胆囊癌的多层螺旋CT表现。方法分析28例经病理证实的胆囊癌多层螺旋CT平扫和三期增强扫描的强化特点。结果本组28例胆囊癌与肝实质强化比较,平扫等密度23例,低密度5例,在动脉期呈低密度3例、等密度4例、高密度21例,在门脉期呈等密度22例,高密度6例,在平衡期呈等密度24例、高密度4例。肿瘤表现为壁局限性增厚(17例),腔内结节(6例),腔内肿块(5例)。结论胆囊癌主要表现为胆囊壁局限性不规则增厚和腔内结节,在平扫主要呈等密度,增强扫描强化显著,并具有延迟强化的特点,这些特点对于诊断和鉴别诊断有很高价值。     

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.     

Arterioportal shunt: prevalence in small hemangiomas versus that in hepatocellular carcinomas 3 cm or smaller at two-phase helical CT

PURPOSE: To compare the prevalence of arterioportal (AP) shunting associated with (a) small (< or =3 cm) hemangiomas and (b) hepatocellular carcinomas (HCCs) (< or =3 cm) at two-phase helical computed tomography (CT). MATERIALS AND METHODS: Two-phase helical liver CT was performed in 107 patients (61 men, 46 women; age range, 25-73 years; mean, 48.6 years) with 169 small hemangiomas and in 384 patients (292 men, 92 women; age range, 18-82 years; mean, 58.3 years) with 598 HCCs 3 cm or smaller. Diagnosis of HCC was verified with histologic findings (n = 30) or typical imaging and clinical findings (n = 568); that of all hemangiomas was verified with typical imaging and clinical findings. Three radiologists retrospectively reviewed all CT images in consensus. Contrast material-enhanced CT scans were obtained during the hepatic arterial and portal venous phases. AP shunt was considered to be present when wedge-shaped or irregularly shaped homogeneous enhancement peripheral to tumor appeared at hepatic arterial phase CT and isoattenuation or slight hyperattenuation in that area appeared at portal phase CT. The prevalence of AP shunting associated with hemangiomas and that associated with HCCs were compared with multivariate model testing. Speed of lesion enhancement (rapid enhancement, when extent of intratumoral enhancement at hepatic arterial phase CT was >50%; slow enhancement, when extent of intratumoral enhancement was < or =50%) and presence of AP shunt were correlated with chi2 or Fisher exact testing. RESULTS: AP shunts were more frequently found in hemangiomas (36 lesions [21.3%]) than in HCCs (25 lesions [4.2%]) (P <.001). Twenty-four (38%) of the 64 hemangiomas with rapid enhancement had AP shunts, whereas only 12 (11.4%) of the 105 hemangiomas with slow enhancement had AP shunts (P <.001). There was no significant difference between prevalence of AP shunt in the 573 HCCs with rapid enhancement (24 lesions, 4.2%) and that in the 25 HCCs with slow enhancement (one lesion, 4.0%). CONCLUSION: AP shunts were more frequently seen at two-phase helical CT in small hepatic hemangiomas than in HCCs and thus represent a suggestive but not specific finding of hemangioma. Small hemangiomas with AP shunts tend to show rapid rather than slow enhancement.     

Small hypervascular enhancing lesions on arterial phase images of multiphase dynamic computed tomography in cirrhotic liver: fate and implications

OBJECTIVE: Our purpose was to determine the significance of small hypervascular enhancing lesions exclusively on the arterial phase images of dynamic computed tomography in cirrhotic liver. METHODS: One hundred sixty-nine enhancing lesions (>5 and <30 mm) on the arterial phase images of dynamic computed tomography in 67 patients with cirrhotic liver, not distinguished from background hepatic parenchyma on equilibrium phase images without hypoattenuation density on portal phase images, were subjected to a retrospective assessment in terms of the lesion growth in addition to the location, size, and contour of the lesions, depending on the final diagnoses of the individual lesions. RESULTS: Twenty-eight (17%) of the 169 enhancing lesions were hepatocellular carcinomas (HCCs). All of the 43 wedge-shaped, subcapsular lesions were benign, and 126 nodular or irregular lesions were subcapsularly (benign, n = 59; HCC, n = 11) or centrally (benign, n = 39; HCC, n = 17) located. Significant differences were found between HCCs and benign lesions in terms of their shape (P = 0.002) and location (P = 0.041), and the positive and negative predictive values of centrally located lesions for diagnosing HCCs were 21% and 85%, respectively. The positive and negative predictive values for the diagnosis of HCC based on the lesion growth were 90% and 93%, respectively. CONCLUSIONS: Because of the low positive predictive value of non-wedge-shaped, centrally located, early enhancing lesions in the diagnosis of HCC, the serial follow-up for examining lesion growth is essential to the correct diagnosis of small arterial hypervascular lesions in cirrhotic liver.     

Encapsulated hepatocellular carcinoma: CT-pathologic correlations

This study is a retrospective evaluation of the correlations between the presence and integrity of the capsule of nodular hepatocellular carcinomas (HCC) by dynamic CT and histopathology, with histopathologic evidence of tumor propagation to surrounding hepatic parenchyma. Dynamic CT scans of 75 nodular HCCs in 73 patients (61 men, 12 women; age range, 32–81; mean, 53) were evaluated regarding capsule visualization and integrity. Histopathologic findings of HCCs in resected specimens were correlated with the presence of a capsule, tumor invasion onto the capsule, and with the presence of microvascular emboli in the surrounding liver parenchyma. On histopathologic examination, capsules were present in 57 of 75 nodular HCCs; the capsules were invaded by tumor in 18 nodules and there were microvascular emboli around the nodular HCC in 49 cases. Capsule visualization by CT was correlated with the presence of capsule by histopathology (P<0.001). Disruption of capsule by CT was correlated with tumor invasion by histopathology (P=0.003) and with microvascular tumor emboli (P<0.001). The presence and structural integrity of HCC capsules on CT was closely correlated with the presence of capsule on histopathology and the absence of microvascular tumor emboli.     

Lipiodol retention and massive necrosis after lipiodol-chemoembolization of hepatocellular carcinoma: Correlation between computed tomography and histopathology

This retrospective study examined the computed tomography (CT) criteria for judging the effectiveness of transcatheter arterial Lipiodolchemoembolization (Lp-chemo-TAE) in 35 cases with hepatocellular carcinoma (HCC). Massive necrosis, defined as involving 97% or more of the HCC nodule, was observed in 15 cases after Lp-chemo-TAE, whereas nonmassive necrosis, defined as involving ≤96% of the HCC nodule, was observed in the remaining 20 cases. In 12 of 15 cases (80%) with massive necrosis, uniform dense retention of Lipiodol (Lp) was observed throughout the HCC nodule on CT images 3–4 weeks after Lp-chemo-TAE as opposed to only one (5%) of 20 cases with nonmassive necrosis (p<0.01). Eight of nine cases (89%) with massive necrosis had tumor attentuation values of 365 Hounsfield units (HU) or greater on CT images 3–4 weeks after embolization, as opposed to only four (27%) of 15 cases with nonmassive necrosis (p<0.01). We conclude that the effectiveness of the Lp-chemo-TAE can be judged on CT from the degree and duration of Lp retention in the HCC nodule and the measurement of the attenuation value of the HCC nodule.     

肝脏双期螺旋CT扫描的临床应用价值

目的:研究双期螺旋CT最佳扫描技术及其在肝肿瘤或肝癌探测中的应用。材料与方法:35例无肝肿瘤和17例肝肿瘤患者均经双期螺旋CT行肝脏扫描,于动脉期和门静脉期观察了正常肝脏和肝细胞癌病灶中的CT表现。结果:正常肝脏与肝细胞癌的CT表现有明显不同。在12例肝细胞癌患者中确切看到了14个肝细胞癌病灶,其中13个病灶在动脉期呈高密度,12个病灶在门静脉期呈低密度,动脉期和门静脉期肝细胞癌的检出率分别为92.8％和85.7％。结论:选择最优化扫描参数,可清晰显示肝细胞癌的增强特点,并显著提高其病变的检出率,因此,双期螺旋CT扫描可当作探测肝肿瘤或肝细胞癌的常规方法。     

Value of the unenhanced phase for detection of hepatocellular carcinomas 3 cm or less when performing multiphase computed tomography in patients with cirrhosis

OBJECTIVE: To determine whether unenhanced images are of added benefit to dual-phase computed tomography (CT) for detection of hepatocellular carcinomas (HCCs) 3 cm or less. METHODS: Thirty-six patients with cirrhosis underwent unenhanced, arterial and portal venous phase CT, 17 with pathologically proven HCCs 3 cm or less and 19 without HCC. Two radiologists reviewed dual-phase images with and without unenhanced images. Presence or absence of HCC in each segment (n = 324) and subjective added benefit of unenhanced images were recorded. RESULTS: For readers 1 and 2, unenhanced CT was subjectively helpful in 16 (5%) of 324 and 23 (7%) of 324 segments. Sensitivity and area under the receiver operating characteristic curve were identical for dual-phase versus triple-phase images for reader 1 (82.4% and 0.882) and reader 2 (100% and 0.997). CONCLUSIONS: Addition of unenhanced to dual-phase CT does not statistically significantly increase the diagnostic accuracy or sensitivity for HCCs 3 cm or less.     

The dynamic computed tomography of small hepatocarcinomas treated by US-guided percutaneous ethanol injections. The short- and long-term follow-up aspects]

Dynamic CT studies with an automatic injector of iodinated contrast medium were performed in 22 patients affected with 29 hepatocellular carcinomas (HCCs) (phi: 0.8-4.5 cm) before and after treatment with percutaneous ethanol injection (PEI) and during the follow-up period, every 6-9 months. Before PEI, most of the HCCs showed contrast enhancement on CT scans. Treatment was suspended when US-guided fine-needle biopsy demonstrated the absence of malignant cells and when the lesions were unenhanced on dynamic CT scans. Dynamic CT detected 21 HCCs (72.4%) before PEI and 24 HCCs (82.8%) after PEI and during the follow-up period. After PEI, 14 HCCs exhibited a thin and hyperdense peripheral rim on dynamic CT scans. Nine of these lesions, with long-term follow-up (12-31 months), have a smaller diameter than the primary lesion; 6 patients have no HCC recurrence. The authors conclude that dynamic CT is useful for evaluating the effectiveness of PEI in the treatment of HCCs; moreover, their personal experience suggests that the finding of a thin and hyperdense peripheral rim cannot always be related to viable cancerous tissue.     

Growth rate of hepatocellular carcinoma: evaluation with serial computed tomography or magnetic resonance imaging

OBJECTIVE: To evaluate the growth rate of untreated hepatocellular carcinoma (HCC) by calculating tumor volume doubling time (TVDT) on serial computed tomography (CT) or magnetic resonance imaging (MRI) and to predict TVDT based on initial tumor size. METHODS: Sixteen untreated HCCs in 11 patients with cirrhosis who underwent serial CT or MRI at our institution were retrospectively identified. Two independent readers recorded bidimensional measurements for all tumors, which were used to determine tumor volume (TV). Growth rate was expressed as TVDT. A mathematic model was used to predict TVDT based on baseline tumor size. RESULTS: Mean baseline and follow-up TVs were 10.5 cm3 (range: 0.7-243.6 cm3) and 22.0 cm3 (range: 2.5-870.8 cm3), respectively. Mean duration of follow-up was 176 days (range: 76-472 days). Mean TVDT was 127 days (95% confidence interval: 80, 203; range: 17.5-541.4 days). Expected TVDT could be expressed as TVDT = 114 x (baseline volume)0.14 (P < 0.002). CONCLUSION: The results of this study suggest a preferred interval follow-up of approximately 4.5 months (127 days) for HCC screening. Small HCCs show a tendency toward faster growth and may require shorter follow-up to demonstrate progression.     

Three-dimensional perfusion imaging of hepatocellular carcinoma using 256-slice multidetector-row computed tomography

Purpose  The aim of this study was to evaluate the clinical capability of three-dimensional (3D) perfusion imaging of hepatocellular carcinoma (HCC) by performing dynamic scanning using a 256-slice multidetector-row CT (MDCT) scanner. Materials and methods  Two patients with HCC were examined in this study. They were scheduled to undergo transcatheter arterial infusion therapy using an arterial infusion reservoir system. The CT system used was a newly developed prototype scanner of 256-slice MDCT. Dynamic CT scanning was performed with intraarterial injection via the reservoir route, and perfusion analysis was done based on the 3D data. Results  The blood flow volume per unit volume in the tumors was significantly increased compared with that in normal hepatic parenchyma. Using a 3D workstation, 3D perfusion images could be displayed by fusing CT images with perfusion images about blood flow volume. Conclusion  Three-dimensional perfusion images, which enable 3D evaluation of perfusion in HCCs, can be generated using 256-slice MDCT.     

Feasibility study of computed tomography colonography using limited bowel preparation at normal and low-dose levels study

The purpose was to evaluate low-dose CT colonography without cathartic cleansing in terms of image quality, polyp visualization and patient acceptance. Sixty-one patients scheduled for colonoscopy started a low-fiber diet, lactulose and amidotrizoic-acid for fecal tagging 2 days prior to the CT scan (standard dose, 5.8–8.2 mSv). The original raw data of 51 patients were modified and reconstructed at simulated 2.3 and 0.7 mSv levels. Two observers evaluated the standard dose scan regarding image quality and polyps. A third evaluated the presence of polyps at all three mSv levels in a blinded prospective way. All observers were blinded to the reference standard: colonoscopy. At three times patients were given questionnaires relating to their experiences and preference. Image quality was sufficient in all patients, but significantly lower in the cecum, sigmoid and rectum. The two observers correctly identified respectively 10/15 (67%) and 9/15 (60%) polyps ≥10 mm, with 5 and 8 false-positive lesions (standard dose scan). Dose reduction down to 0.7 mSv was not associated with significant changes in diagnostic value (polyps ≥10 mm). Eighty percent of patients preferred CT colonography and 13% preferred colonoscopy (P<0.001). CT colonography without cleansing is preferred to colonoscopy and shows sufficient image quality and moderate sensitivity, without impaired diagnostic value at dose-levels as low as 0.7 mSv.     

Hepatic attenuation differences associated with obstruction of the portal or hepatic veins in patients with hepatic abscess

OBJECTIVE: The purpose of our study was to determine the nature of the association between the attenuation difference of the hepatic parenchyma surrounding an abscess and obstruction of the regional portal vein or of the hepatic vein. MATERIALS AND METHODS: Helical CT scans of 60 patients with hepatic abscess were analyzed for the presence of complete or partial obstruction of the portal or hepatic veins and for attenuation differences in the surrounding parenchyma. Clinical (age, sex, underlying disease, and microorganism) and CT (obstruction of the portal or hepatic vein and number, location, and size of abscesses) findings were analyzed statistically for possible associations with each of regional parenchymal hyper- and hypoattenuation by using the chi-square test and multivariate logistic regression analysis. RESULTS: Regional parenchymal hyperattenuation was identified in 40 patients (67%). More patients with portal vein obstruction showed regional parenchymal hyperattenuation than patients without portal vein obstruction (22/27 patients vs 18/33, p = 0.028), and more patients with hepatic vein obstruction showed regional parenchymal hypoattenuation than those without hepatic vein obstruction (11/21 vs 3/39, p = 0.0003). Multivariate logistic regression analysis showed that portal venous obstruction was the only statistically significant predictor of regional parenchymal hyperattenuation (p = 0.032; odds ratio, 3.7) and that parenchymal hypoattenuation was associated with hepatic venous obstruction (p = 0.001; odds ratio, 44.9). CONCLUSION: Parenchymal hypo- and hyperattenuation are frequently observed in the hepatic region surrounding an abscess on dynamic CT. Moreover, these parenchymal attenuation differences are associated with regional portal or hepatic vein obstruction.     

Granulocytic sarcoma of bowel: CT findings

PURPOSE: To evaluate retrospectively the computed tomographic (CT) findings of granulocytic sarcoma of the bowel. MATERIALS AND METHODS: The institutional review boards of all participating institutions approved this study and waived the requirement for informed consent. CT scans were retrospectively reviewed in eight patients (seven men, one woman; age range, 23-71 years; mean age, 46 years) with pathologically proved granulocytic sarcoma of the small and/or large bowel. CT findings were evaluated with regard to the sites, morphologic characteristics, and contrast material enhancement patterns of the lesions, along with other ancillary findings (ie, peritoneal and mesenteric infiltration, ascites, lymphadenopathy, bowel perforation, and obstruction). RESULTS: Eight patients had a total of 13 lesions in the bowel (of which eight were pathologically proved), involving the duodenum (n=1), jejunum (n=2), ileum (n=5), sigmoid colon (n=1), and rectum (n=4); multifocal bowel lesions were noted in four patients. The lesion varied in shape, with wall thickening alone in three of 13 lesions, an intraluminal polypoid mass in four, an exophytic mass in one, and a combination of findings in five. Contrast material enhancement, relative to the back musculature, showed isoattenuation in seven lesions, hyperattenuation in four, and hypoattenuation in two. Five of eight patients had multiple peritoneal masses with diffuse mesenteric or peritoneal infiltration. Ascites was present in six of eight patients; lymphadenopathy (especially in the mesentery), in five; bowel perforation, in two; and bowel obstruction, in one. CONCLUSION: Granulocytic sarcoma of the bowel is characterized by variability in shape and contrast enhancement and has a high predilection for mesenteric and peritoneal spread.     

Findings of multidetector row computed tomography of HCCs treated by HIFU ablation

Purpose

We evaluated the efficacy of high-intensity focused ultrasound (HIFU) ablation for hepatocellular carcinoma (HCC), and a long-term study by follow-up multidetector-row computed tomography (CT) was conducted to evaluate the changes occurring in the treatment area following the HIFU ablation.

Materials and methods

HIFU ablation was carried out in 14 patients with small HCCs (≤3 lesions, ≤3 cm in diameter). The HIFU system (Chongqing Haifu Tech) was used under ultrasound guidance. The evaluations were performed by follow-up CT at 1 week, 1, 3, 6 and 12 months after the HIFU ablation.

Results

HIFU ablation was carried out successfully in 11 of the 14 patients. At 1 week after the HIFU, a peripheral rim enhancement was found in all cases (100%). This finding was persistent in 6 of the 11 cases (54.5%) at 1 month, and in 1 of the 11 (9%) cases at 3 months after HIFU ablation. In all cases, the rim enhancement disappeared by 6 or 12 months after the HIFU ablation. At the 12 months follow-up, a decrease in the diameter of the ablated lesions was found. The enhancement around the treated area was found to be persistent at the 12 months follow-up in the one case of recurrence of the treated site in which the safety margin was not sufficiently wide. During the follow-up period, there were 2 cases with residual of HCC tumors. We performed radiofrequency ablation (RFA) for these residual tumors after the HIFU ablation.

Conclusion

To ascertain the cause of the peripheral enhancement on follow-up CT images after the HIFU ablation, in particular, to determine whether it might be caused by residual tumor or recurrence at the treated site, careful follow-up is important, especially in cases where the safety margin of the ablated area was not sufficiently wide.     

Xenon-inhalation computed tomography for noninvasive quantitative measurement of tissue blood flow in hepatocellular carcinoma

OBJECTIVE: The purpose of this study was to separately measure the arterial and portal venous tissue blood flow (TBF) of hepatocellular carcinoma (HCC) with a noninvasive method using xenon inhalation CT (xenon-CT) and to differentiate between well-differentiated HCCs and moderately and poorly differentiated HCCs. MATERIALS AND METHODS: Total, arterial and portal venous TBFs of 38 surgically proven HCC nodules from 38 patients were measured by means of xenon-CT. Serial abdominal CT scans were obtained before and after inhalation of nonradioactive xenon gas. TBF was computed using the Fick principle, after which the correlation between TBF and pathologic features of the tumors was determined. RESULTS: Total, arterial, and portal venous TBFs of HCC were 125.7 +/- 59.9 mL/min/100g, 102.5 +/- 37.3, and 22.2 +/- 11.4, respectively, and the corresponding findings for hepatic parenchyma were 67.3 +/- 13.1, 25.2 +/-9.6, and 42.4 +/- 11.0. Total and arterial TBFs of HCC were significantly higher than those of the hepatic parenchyma (P < 0.01), whereas portal venous TBF of HCC was significantly lower than that of hepatic parenchyma (P < 0.01). Arterial TBF of moderately or poorly differentiated HCC (120.4 +/- 38.2) was significantly higher than that of well-differentiated HCC (60.4 +/- 43.5) (P < 0.01). CONCLUSIONS: Arterial and portal venous TBFs of HCC could be measured separately, noninvasively, and safely with xenon-CT. Correlation between TBF and pathologic features of tumors indicate that xenon-CT can be used to differentiate between well-differentiated HCCs and moderately and poorly differentiated HCCs.     

Dynamic computed tomography during arterial portography: the most sensitive examination for small hepatocellular carcinomas

The efficacy of dynamic sequential CT with table incrementation during arterial portography (DSCTI-AP) in the detection of small hepatocellular carcinomas (HCC) (less than 3 cm in diameter and less than three in number) was analyzed in comparison with other imaging methods including radionuclide (RN) liver scans, ultrasound (US), CT, selective celiac angiography (SCA), and infusion hepatic angiography (IHA). The sensitivity of each study in detecting 19 cases of small HCC was as follows: RN, 16%; US, 63%; CT, 58%; SCA, 58%; IHA, 83%; and DSCTI-AP, 95%. Three of 19 cases were diagnosed only by DSCTI-AP and one case that could not be visualized by DSCTI-AP was opacified by IHA. Dynamic sequential CT with table incrementation during arterial portography was superior to IHA in visualizing small HCCs.     

Nodular hepatocellular carcinoma: variation of tumor conspicuity on single-level dynamic scan and optimization of fixed delay times for two-phase helical CT

PURPOSE: The purpose of this work was to determine the optimal delay times in two-phase helical CT for nodular hepatocellular carcinoma (HCC). METHOD: Twenty-four patients with nodular HCC (size 2.1-6.7 cm, mean 4.2 cm) were divided into three groups to undergo single-level dynamic CT with 150 ml of contrast material (iodine load of 45 g) at a rate of 3 ml/s. CT acquisition started 10, 30, or 60 s after the injection for each group, respectively, and lasted for 110 or 120 s. The optimal 20 s windows that allowed a tumor-to-liver contrast of >10 HU were determined in the pooled tumor-to-liver contrast curve. RESULTS: The determined temporal windows were 36-56 and 130-150 s, respectively. However, each window was not appropriate in seven (33%) and five (36%) patients because of the individual variations of the contrast curve. CONCLUSION: There is no optimal fixed delay time that is appropriate in all individual patients. The best delay times are 36 and at least 130 s with our injection protocol.