Hiromichi Oi

Optimal phases of dynamic CT for detecting hepatocellular carcinoma: evaluation of unenhanced and triple-phase images

AbstractBackground: To determine the optimal phases of dynamic computed tomography (CT) for detecting hepatocellular carcinoma (HCC). Methods: Fifty-two patients with 85 HCC nodules were examined by means of unenhanced and triple-phase CT images of the whole liver. The time for obtaining the arterial-phase images was 25–55 s after intravenous bolus injection of contrast material, the time for obtaining the portal venous-phase images was 65–100 s, and the time for obtaining late-phase images was 145 s to 4 min. Detectability of the HCC nodules for all phases was statistically compared. Results: The detection rates for the arterial- and late-phase images were significantly higher than for the unenhanced and portal venous-phase images (p < 0.01). The combination of arterial- and late-phase images showed the same number of HCC nodules in the same number of patients as did the combination of unenhanced and triple-phase images. Conclusion: The combination of the arterial- and late-phase imagings was best for detecting HCC nodules.

Detection of hypervascular hepatocellular carcinoma by dynamic MRI and dynamic spiral CT

Objective Our goal was to evaluate the detectability of hypervascular hepatocellular carcinomas (HCCs) by multislice dynamic MRI and dynamic spiral CT. Materials and Methods Prior to transcatheter arterial chemoembolization (TACE) with iodized oil, the liver was subjected to T1− and T2-weighted SE-MRI, multislice dynamic MRI after intravenous bolus injection of Gd-DTPA, early phase imaging with spiral CT (dynamic spiral CT) after intravenous bolus injection of contrast medium (at a rate of 2 or 3 ml/s), and delayed phase CT in 64 patients with 208 HCC nodules. The detectability of HCCs by MRI and CT was evaluated retrospectively compared with CT after TACE as a gold standard. Results The detectability of nodules < 1 cm in diameter was superior with dynamic MRI (67%) and dynamic spiral CT (50%) in comparison with SE-MRI (26%) and delayed phase CT (11%) (p < 0.01). The detectability of these tumors with dynamic MRI was significantly superior to that with dynamic spiral CT using an injection rate of 2 ml/s (p < 0.01), but not significantly different from that of dynamic spiral CT using a rate of 3 ml/s. Conclusion Dynamic MRI and dynamic spiral CT are comparable for detecting hypervascular intrahepatic metastases of HCC.

Sensitivity in Detection of Hypervascular Hepatocellular Carcinoma by Helical CT with intra-arterial injection of contrast medium, and by helical CT and MR Imaging with intravenous injection of contrast medium

Purpose: to determine the effectiveness of i.a. contrast-enhanced helical CT and of i.v. contrast-enhanced helical CT and MR imaging, in detecting hyper-vascular hepatocellular carcinoma (HCC) Material and Methods: Fifty patients with 125 hypervascular HCC nodules underwent helical CT both during arterial portography (CTAP) and during hepatic arteriography (CTHA). Helical CT and MR imaging of the entire liver with i.v. administration of contrast medium were also performed. Helical CT images were obtained at 30–33 s (arterial-phase CT) and at 5 min (equilibrium-phase CT) after the initiation of an i.v. bolus injection of contrast medium. After T1- and T2-weighted spin-echo MR imaging, gradient-echo images during breath-holding were obtained prior to and 20 s, 1 min, and 2 min after the bolus administration of 0.1 mmol/kg of gadopentetate dimeglumine (dynamic MR). the sensitivity and positive predictive value of the various techniques were evaluated and compared Results: in terms of sensitivity for hypervascular HCC nodules of less than 1 cm in diameter, CTAP (90%) and CTHA (88%) were significantly superior to dynamic MR imaging (44%), arterial-phase CT (39%), spin-echo MR imaging (20%), and equilibrium-phase CT (7%) (p>0.001). However, there was no significant difference in the techniques with regard to the detection of lesions equal to or more than 2 cm in diameter Conclusion: for detecting small hypervascular HCCs, helical CT with i.a. contrast enhancement is superior to helical CT and MR imaging with i.v. enhancement

Detectability of hypervascular hepatocellular carcinoma by arterial phase images of MR and spiral CT.

The ability of arterial phase images of breath-hold MR imaging and spiral CT to detect hypervascular hepatocellular carcinomas (HCCs) was evaluated. Prior to transcatheter arterial chemoembolization (TACE) with iodized oil, MR images and spiral CT during i.v. bolus injection of contrast medium (IV-MR imaging and IV-spiral CT) and spiral CT during intraarterial injection of contrast media through catheter (IA-spiral CT) of the entire liver were obtained in 24 consecutive patients with 93 HCCs. In the detection of HCCs less than 1 cm in diameter, IA-spiral CT (87.3%) was superior to IV-MR imaging (63.5%) and IV-spiral CT (54.0%) (p < 0.001). There was no significant difference in detectability in any tumor size between IV-MR imaging and IV-spiral CT. IA-spiral CT was the best for detecting hypervascular HCCs, and there was no significant difference between IV-MR imaging and IV-spiral CT.

Helical CT angiography of living renal donors : Comparison with 3D Fourier transformation phase contrast MRA

PURPOSE The purpose of this study was to determine whether helical CT angiography (CTA) or MR angiography (MRA) is the optimal method to use as a preoperative examination for anatomic arterial assessment of living renal donors. METHOD Eighteen candidates to be renal donors underwent helical CTA, 3D Fourier transformation phase contrast (3D-FT-PC) MRA, and digital subtraction angiography (DSA). The CTA and MRA were interpreted separately by three readers independently, and these results were correlated with the findings of DSA. RESULTS DSA showed nine accessory renal arteries and 10 prehilar branches. CTA revealed seven or eight accessory renal arteries. MRA showed six or seven accessory arteries. Of 10 prehilar branches, 7-9 branches were detected with CTA and 5-8 branches with MRA. CONCLUSION Helical CTA is superior to 3D-FT-PC MRA for evaluating the arterial anatomy of living renal donors.

MR imaging of cervical carcinoma: comparison among T2-weighted, dynamic, and postcontrast T1-weighted images with histopathological correlation

Abstract.Background: To identify the reasons for misdiagnosis of the degree of stromal invasion by uterine cervical cancer with various magnetic resonance sequences. Methods: T2-weighted, dynamic, and postcontrast T1-weighted images were obtained in the sagittal plane in 20 patients with uterine cervical cancer. After evaluating these sequences for the degree of stromal invasion, histologic specimens were directly correlated with these images. Results: The degree of stromal invasion was correctly diagnosed in 15 of the 20 cases on T2-weighted images, in 12 on dynamic images, and in eight on postcontrast T1-weighted images. All misdiagnoses were due to overestimation. Histologically, peritumoral stroma showed inflammation or edema in two patients, whereas no histological abnormality was found in the other patients. A hyperintense rim, i.e., a peritumoral enhanced ring-shaped structure, was observed on the enhanced images of five patients. The hyperintense rim corresponded to the periphery of the tumor in three patients and to the cervical stroma in two patients. Conclusion: T2-weighted images permitted the most accurate evaluation of stromal invasion by uterine tumors. Overdiagnosis may be due to an abnormal intensity of the cervical stroma, which was observed more frequently on dynamic and postcontrast T1-weighted images than on T2-weighted images.

Dynamic MR imaging for extraserosal invasion of advanced gastric cancer

Abstract. Dynamic magnetic resonance (MR) images in 37 patients with gastric cancers were obtained by a two-dimensional fast multiplanar spoiled gradient technique. The degree of tumor invasion was classified into four grades regarding a low-intensity band between the stomach and surrounding fat. Advanced gastric cancer was strongly enhanced, appearing as a thickened wall, by the contrast medium during the early to delayed phases of dynamic studies. The extent of invasion of the adjacent organs was diagnosed by the difference in enhancement between the tumor and the parenchyma. The sensitivity of extraserosal invasion was 93%. Dynamic MR diagnosis is useful for evaluating the extent of gastric carcinoma.

Follow-up study of combination treatment (TAE and PEIT) for unresectable hepatocellular carcinoma.

The subjects were 35 patients with unresectable hepatocellular carcinoma. The patients were divided into a transcatheter arterial embolization group (TAE group, 18 cases) and a combination therapy group receiving both TAE and percutaneous ethanol injection therapy (TAE+PEIT group, 17 cases). The 50% survival period was 21.1 months for the TAE group and 37.8 months for the TAE+PEIT group (P<0.05). The longest survival period in the TAE group was 89 months. In the TAE+PEIT group, one patient has survived for 59 months. The actuarial 1-, 2-, and 3-year survival rates for the TAE group were 82%, 45%, and 22%, respectively. For the TAE+PEIT group the rates were 83%, 64%, and 64%, respectively. The TAE+PEIT group showed a significantly higher survival rate in the 895-to 1.074-day period as compared with the TAE groupP<0.05). Overall, the survival rate tended to be higher in the TAE-PEIT group (P<0.1). The therapeutic responses of tumors were measured by the maximal reduction rate within 6 months of TAE and PEIT. In the TAE group, a PR was seen in only four cases. In the TAE+PEIT group, CRs and PRs were achieved significantly more frequently than in the TAE group. When the patients were divided into a responder group (CR, PR, and MR) and a nonresponder group (NC and PD), survival was significantly longer in the responder group. The findings of the present study suggest that the combination therapy was useful for improving the survival of patients with unresectable hepatocellular carcinoma.

Sensitivity of double-phase helical CT during arterial portography for detection of hypervascular hepatocellular carcinoma.

PURPOSE The purpose of our work was to determine the usefulness of double-phase helical CT during arterial portography (CTAP) for the detection of hypervascular hepatocellular carcinoma (HCC). METHOD Eighty-four patients with 176 hypervascular HCC nodules underwent double-phase CTAP. Hypervascular HCCs were diagnosed by iodized oil CT after transcatheter arterial chemoembolization (TACE). The first-phase images were obtained 30 s after the initiation of injection of a nonionic iodinated contrast medium into the superior mesenteric artery or splenic artery, and the second-phase images were obtained after 70 s. These images were interpreted separately for detection of HCC. RESULTS The double-phase CTAP detected two nodules and six nodules that were missed by the first- and second-phase images, respectively. The sensitivity for hypervascular HCC nodules was 89% for the first phase, 91% for the second phase, and 93% for the first phase and second phase combined. The double-phase CTAP showed significantly superior sensitivity to the first-phase CTAP for detecting HCC nodules (p < 0.05). However, there was no statistically significant difference between the sensitivities of the double-phase CTAP and the second-phase CTAP. The positive predictive values of the double-phase images were inferior to those of either the first-phase or the second-phase images alone. CONCLUSION Double-phase helical CTAP was found to be no better than second-phase CTAP alone for the detection of hypervascular HCC nodules.

Effective cases of transcatheter arterioportal chemoembolization with high-dose iodized oil for hepatocellular carcinoma

By administering an excessive amount of iodized oil via the hepatic artery, anticancer drugs in the iodized oil flow into the portal vein through the arterioportal communication. This phenomenon permits chemotherapy against extracapsular infiltration by a hepatocellular carcinoma (HCC) nourished by the portal blood flow. From May 1983 through July 1992, 240 cases of HCC underwent transcatheter arterioportal chemoembolization (TAPCE) with more than 5 ml of iodized oil (mean, 15 ml) in our hospital. In all, 32 patients survived for more than 3 years, and the factors favoring the efficacy of TAPCE therapy were investigated. Doxorubicin (mean, 46 mg) was given to 31 patients and 20 mg mitomycin C was given to 1 patient. The patients included one Stage 1 case, 13 Stage 2 cases, 17 Stage 3 cases, and one Stage 4 case. The mean tumor size was 5.0 cm, and portal invasion was suggested in 8 cases by angiography. The tumors were divided into 5 types: 13 cases of the single nodular type (SN), 7 cases of the single nodular type with proliferation (SN-P), 3 cases of the multinodular fused type (MN-F), 5 cases of the multinodular type (MN), and 4 cases of the massive type. A complication of liver dysfunction was detected in 14 cases, and half of them were Childs class C. In all, 7 patients underwent hepatectomy and 6 received percutaneous ethanol injection after TAPCE. The treated area of TAPCE was classified as segmental, lobar, or total. Segmental and lobar administration of TAPCE yielded statistically effective results, and their tumor response rate was 86%. All of the MN-F and massive types showed a good tumor response. The incidence of intrahepatic distant metastasis was higher in the localized TAPCE group than in the total TAPCE group. Segmental and lobar TAPCE should be applied for localized infiltrating HCCs, even in cases associated with liver cirrhosis, but these methods have a limited capacity to prevent distant intrahepatic metastasis.By administering an excessive amount of iodized oil via the hepatic artery, anticancer drugs in the iodized oil flow into the portal vein through the arterioportal communication. This phenomenon permits chemotherapy against extracapsular infiltration by a hepatocellular carcinoma (HCC) nourished by the portal blood flow. From May 1983 through July 1992, 240 cases of HCC underwent transcatheter arterioportal chemoembolization (TAPCE) with more than 5 ml of iodized oil (mean, 15 ml) in our hospital. In all, 32 patients survived for more than 3 years, and the factors favoring the efficacy of TAPCE therapy were investigated. Doxorubicin (mean, 46 mg) was given to 31 patients and 20 mg mitomycin C was given to 1 patient. The patients included one Stage 1 case, 13 Stage 2 cases, 17 Stage 3 cases, and one Stage 4 case. The mean tumor size was 5.0 cm, and portal invasion was suggested in 8 cases by angiography. The tumors were divided into 5 types: 13 cases of the single nodular type (SN), 7 cases of the single nodular type with proliferation (SN-P), 3 cases of the multinodular fused type (MN-F), 5 cases of the multinodular type (MN), and 4 cases of the massive type. A complication of liver dysfunction was detected in 14 cases, and half of them were Childs class C. In all, 7 patients underwent hepatectomy and 6 received percutaneous ethanol injection after TAPCE. The treated area of TAPCE was classified as segmental, lobar, or total. Segmental and lobar administration of TAPCE yielded statistically effective results, and their tumor response rate was 86%. All of the MN-F and massive types showed a good tumor response. The incidence of intrahepatic distant metastasis was higher in the localized TAPCE group than in the total TAPCE group. Segmental and lobar TAPCE should be applied for localized infiltrating HCCs, even in cases associated with liver cirrhosis, but these methods have a limited capacity to prevent distant intrahepatic metastasis.