Takashi Mitani

Identifying Feeding Arteries During TACE of Hepatic Tumors: Comparison of C-Arm CT and Digital Subtraction Angiography

OBJECTIVE This study compares the diagnostic accuracy of C-arm CT with digital subtraction angiography (DSA) in identifying tumor-feeding arteries during superselective transarterial chemoembolization (TACE). MATERIALS AND METHODS Thirty-three consecutive patients with hepatocellular carcinoma (HCC) underwent superselective TACE using a flat-detector angiographic system. Angiographic operators determined which feeding arteries were potentially supplying the target tumor. When two or more feeding arteries were possible, all were included. Superselective DSA and C-arm CT were sequentially performed for each studied artery. Four independent observers separately viewed the DSA and C-arm CT images and used a 5-point grading scale to determine whether a studied artery supplied the target tumor. Diagnostic performance was compared using receiver operating characteristic (ROC) analysis. Sensitivity, specificity, and accuracy were calculated for arteries rated as definite or probable tumor feeders. Iodized oil accumulation on follow-up CT was the reference standard. RESULTS We examined 58 possible feeding arteries in 33 patients. Among the studied arteries, follow-up CT confirmed that 33 were verified tumor-feeding arteries, and the remaining 25 were not. C-arm CT resulted in a significantly larger area under the ROC curve (A(z) = 0.995) compared with DSA (A(z) = 0.841). The sensitivity, specificity, and accuracy of C-arm CT (96.9%, 97.0%, and 96.9%, respectively) were significantly higher than those for DSA (77.2%, 73.0%, and 75.4%). CONCLUSION C-arm CT is superior to DSA for identifying tumor-feeding arteries during superselective TACE for HCC.

Survival after C-arm CT-assisted chemoembolization of unresectable hepatocellular carcinoma

PURPOSE To compare patient survival after transarterial chemoembolization with and without intraprocedural C-arm computed tomography (CT) in patients with unresectable hepatocellular carcinoma. MATERIALS AND METHODS We retrospectively reviewed the records of 130 patients with unresectable hepatocellular carcinoma who underwent lipiodol-based chemoembolization using a C-arm cone-beam system. We compared patients who underwent chemoembolization with angiography alone (69 patients; April 2005-July 2007) to those who underwent C-arm CT-assisted chemoembolization (61 patients; July 2007-April 2010). Overall and local progression-free survivals were compared using the Kaplan-Meier estimator with log-rank testing. Univariate and multivariate analyses were performed using the Cox proportional hazards model. RESULTS Overall survival rates of patients who underwent chemoembolization with and without C-arm CT assistance were 94% and 79%, 81% and 65%, and 71% and 44% at 1, 2, and 3 years, respectively. Local progression-free survival rates of these patients were 43% and 27%, 31% and 10%, and 26% and 5% at 1, 2, and 3 years, respectively. Patients receiving C-arm CT-assisted chemoembolization had significantly higher overall (P=0.005) and local progression-free (P=0.003) survival rates than those receiving chemoembolization with angiography alone. Multivariate analysis showed that C-arm CT assistance was an independent factor associated with longer overall survival (hazard ratio, 0.40; P=0.033) and local progression-free survival (hazard ratio, 0.25; P=0.003). CONCLUSION C-arm CT usage in addition to angiography during transarterial chemoembolization prolongs survival in patients with unresectable hepatocellular carcinoma.

Detection of hepatocellular carcinoma: comparison of angiographic C-arm CT and MDCT.

OBJECTIVE The aim of this study was to compare the accuracy, sensitivity, and positive predictive value of C-arm CT with those of MDCT in the detection of hepatocellular carcinoma. MATERIALS AND METHODS We retrospectively evaluated the cases of 50 patients with nodules of hepatocellular carcinoma who underwent biphasic MDCT and selective C-arm CT with flat-detector angiographic systems. We evaluated arterial phase C-arm CT images and the corresponding biphasic MDCT images of 59 hepatic areas in 50 patients. Three independent blinded observers rated both sets of images using a detection confidence scale. The diagnostic accuracy of the two techniques was compared on the basis of area under alternative free-response receiver operating characteristic curve (A(1)). Focal accumulation of iodized oil was the reference standard. RESULTS Accuracy was significantly higher for C-arm CT (A(1) = 0.830) than for MDCT (A(1)= 0.618) for lesions smaller than 10 mm in diameter (p < 0.001), but the accuracy of the two techniques did not differ significantly for lesions measuring 10 mm or larger. C-arm CT was significantly more sensitive than MDCT in the detection of lesions 20 mm or smaller (74.1% vs 34.0% for lesions < 10 mm [p < 0.001]; 94.7% vs 77.1% for lesions 10-20 mm [p < 0.001]). The positive predictive values of the two techniques did not differ significantly irrespective of lesion size. CONCLUSION Compared with biphasic MDCT, C-arm CT depicted hepatocellular carcinoma lesions smaller than 10 mm with more accuracy and those 20 mm and smaller with more sensitivity. The two techniques were equally accurate in the detection of hepatocellular carcinoma lesions 10 mm in diameter and larger.

Prostate cancer detection with MRI: is dynamic contrast-enhanced imaging necessary in addition to diffusion-weighted imaging?

PURPOSE To assess the feasibility of using magnetic resonance imaging for prostate cancer detection without using a contrast material. MATERIALS AND METHODS T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced imaging (DCEI) were performed using a phased-array coil at 1.5 T. These examinations were performed in 178 patients with elevated serum prostate-specific antigen levels ( > 4.0 ng/mL) before systematic needle biopsy. Two radiologists independently evaluated images from DWI, DCEI, and a combination of the two techniques by referring to a T2WI image and by using a predefined confidence scale for cancer detection. The right and left halves of the peripheral zone and the central gland were separately rated. The diagnostic performance (A < sub > z < /sub > ) of each technique was assessed by analyzing their associated area under the receiver operating characteristic curves. The results of a biopsy served as a reference standard. RESULTS Prostate cancer was detected in 72 (40.4%) of the 178 patients. For the entire prostate, the diagnostic performances of DWI (Az = 0.848) (P < 0.001) and the combined technique (Az = 0.845) (P < 0.001) were significantly more accurate than that of DCEI (Az = 0.746). DWI (74.8%) (P < 0.001) and the combined technique (72.9%) (P < 0.001) were significantly more sensitive than DCEI (52.8%). The numbers of cancer lesions that were interpreted using only DWI or DCEI were 83 (26.1%) and 13 (4.1%) of the 318 study lesions, respectively. CONCLUSION DWI and the combined technique are more accurate and sensitive than DCEI in the detection of prostate cancer; however, DWI and DCEI play complementary roles in the accurate detection of prostate cancer.

Clinical utility and limitations of tumor-feeder detection software for liver cancer embolization

PURPOSE To evaluate the clinical utility and limitations of a computer software program for detecting tumor feeders of hepatocellular carcinoma (HCC) during transarterial chemoembolization (TACE). MATERIALS AND METHODS Forty-six patients with 59 HCC nodules underwent nonselective digital subtraction angiography (DSA) and C-arm computed tomography (CT) in the same hepatic artery. C-arm CT data sets were analyzed using the software to identify potential tumor feeders during each TACE session. For DSA analysis, 3 radiologists were independently assigned to identify tumor feeders using the DSA images in a separate session. The sensitivity of the 2 techniques in detecting tumor feeders was compared, with TACE findings as the reference standard. Factors affecting the failure of the software to detect tumor feeders were assessed by univariate and multivariate analyses. RESULTS We detected 65 tumor feeders supplying 59 HCC nodules during TACE sessions. The sensitivity of the software to detect tumor feeders was significantly higher than that of the manual assessment using DSA (87.7% vs. 71.8%, P<0.001). Multivariate analysis showed that a tumor feeder diameter of <1.0mm (hazard ratio [HR], 56.3; P=0.003) and lipiodol accumulation adjacent to the tumor (HR, 11.4; P=0.044) were the significant predictors for failure to detect tumor feeders. CONCLUSION The software analysis was superior to manual assessment with DSA in detecting tumor feeders during TACE for HCC. However, the capability of the software to detect tumor feeders was limited by vessel caliber and by prior lipiodol accumulation to the tumor.

C-Arm CT for Assessing Initial Failure of Iodized Oil Accumulation in Chemoembolization of Hepatocellular Carcinoma

OBJECTIVE The purpose of our study was to assess the feasibility of using C-arm CT to detect incomplete accumulation of iodized oil in hepatocellular carcinoma immediately after transarterial chemoembolization (TACE). MATERIALS AND METHODS This retrospective study included 80 hepatocellular carcinoma lesions in 55 patients (41 men and 14 women; mean age, 69.2 years; mean tumor size, 18.1 mm [range, 5-55 mm]) who underwent TACE with a flat-detector C-arm angiographic system. C-arm CT images were acquired at the end of each session, and unenhanced MDCT images were obtained 7 days later. Two independent observers scored both sets of images, using a predefined detection scale for incomplete iodized oil accumulation. The accuracy for predicting residual lesions was compared using the area under the receiver-operating characteristic curve (A(z)). Contrast-enhanced CT findings obtained 1 month after TACE served as reference standards. RESULTS Viable lesions were observed in 18 of the 80 study lesions by contrast-enhanced CT. The accuracy of the C-arm CT (A(z) = 0.816) was not significantly different (p = 0.449) from that of the MDCT (A(z) = 0.841). Sensitivity, specificity, and positive and negative predictive values for C-arm CT (80.5%, 74.2%, 47.5%, and 92.9%, respectively) and MDCT (86.1%, 75.0%, 50.0%, and 94.9%, respectively) did not differ significantly. CONCLUSION C-arm CT is nearly equivalent to MDCT for detecting incomplete iodized oil accumulation after TACE, suggesting that the immediate assessment of iodized oil accumulation with C-arm CT without the need to perform follow-up unenhanced MDCT is likely feasible.

Ablation margin assessment of liver tumors with intravenous contrast-enhanced C-arm computed tomography.

AIM To evaluate the feasibility of intravenous contrast-enhanced C-arm computed tomography (CT) for assessing ablative areas and margins of liver tumors. METHODS Twelve patients (5 men, 7 women; mean age, 69.5 years) who had liver tumors (8 hepatocellular carcinomas, 4 metastatic liver tumors; mean size, 16.3 mm; size range, 8-20 mm) and who underwent percutaneous radiofrequency ablations (RFAs) with a flat-detector C-arm system were retrospectively reviewed. Intravenously enhanced C-arm CT and multidetector computed tomography (MDCT) images were obtained at the end of the RFA sessions and 3-7 d after RFA to evaluate the ablative areas and margins. The ablated areas and margins were measured using axial plane images acquired by both imaging techniques, with prior contrast-enhanced MDCT images as the reference. The sensitivity, specificity, and positive and negative predictive values of C-arm CT for detecting insufficient ablative margins (< 5 mm) were calculated. Statistical differences in the ablative areas and margins evaluated with both imaging techniques were compared using a paired t-test. RESULTS All RFA procedures were technically successful. Of 48 total ablative margins, 19 (39.6%) and 20 (41.6%) margins were found to be insufficient with C-arm CT and MDCT, respectively. Moreover, there were no significant differences between these 2 imaging techniques in the detection of these insufficient ablative margins. The sensitivity, specificity, and positive and negative predictive values for detecting insufficient margins by C-arm CT were 90.0%, 96.4%, 94.7% and 93.1%, respectively. The mean estimated ablative areas calculated from C-arm CT (462.5 ± 202.1 mm(2)) and from MDCT (441.2 ± 212.5 mm(2)) were not significantly different. The mean ablative margins evaluated by C-arm CT (6.4 ± 2.2 mm) and by MDCT (6.0 ± 2.4 mm) were also not significantly different. CONCLUSION The efficacy of intravenous contrast-enhanced C-arm CT in assessing the ablative areas and margins after RFA of liver tumors is nearly equivalent to that of MDCT.

Local tumor progression following lipiodol-based targeted chemoembolization of hepatocellular carcinoma: a retrospective comparison of miriplatin and epirubicin.

Purpose We aimed to compare the local control rates between miriplatin and epirubicin in lipiodol-based transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). Patients and methods Patients who underwent targeted TACE using miriplatin (47 patients, 66 lesions) or epirubicin (64 patients, 79 lesions) as the sole therapy were enrolled. The local control rates were compared using the Kaplan–Meier estimator with the log-rank test. The patient and tumor parameters were subjected to univariate and multivariate analyses using the Cox proportional hazards model. Results The overall local recurrence rates were 39.3% and 31.6% for the miriplatin and epirubicin groups, respectively. The local control rate was significantly higher in the epirubicin group than in the miriplatin group (P < 0.001). The local control rates at 6 months and 1 year were 70.7% and 44.8% for the miriplatin group and 83.4% and 69.2% for the epirubicin group, respectively. Multivariate analysis showed that the serum α-fetoprotein level ≥ 20 ng/mL (hazard ratio 2.96; P < 0.001), miriplatin usage (hazard ratio 2.53; P = 0.002), and Child-Pugh class B (hazard ratio 1.89; P = 0.042) affected local progression. Conclusion Lipiodol-based targeted TACE using miriplatin had inferior local control rates as compared to epirubicin in patients with HCC.

Comparison of the Number of Image Acquisitions and Procedural Time Required for Transarterial Chemoembolization of Hepatocellular Carcinoma with and without Tumor-Feeder Detection Software

Purpose. To compare the number of image acquisitions and procedural time required for transarterial chemoembolization (TACE) with and without tumor-feeder detection software in cases of hepatocellular carcinoma (HCC). Materials and Methods. We retrospectively reviewed 50 cases involving software-assisted TACE (September 2011–February 2013) and 84 cases involving TACE without software assistance (January 2010–August 2011). We compared the number of image acquisitions, the overall procedural time, and the therapeutic efficacy in both groups. Results. Angiography acquisition per session reduced from 6.6 times to 4.6 times with software assistance (P < 0.001). Total image acquisition significantly decreased from 10.4 times to 8.7 times with software usage (P = 0.004). The mean procedural time required for a single session with software-assisted TACE (103 min) was significantly lower than that for a session without software (116 min, P = 0.021). For TACE with and without software usage, the complete (68% versus 63%, resp.) and objective (78% versus 80%, resp.) response rates did not differ significantly. Conclusion. In comparison with software-unassisted TACE, automated feeder-vessel detection software-assisted TACE for HCC involved fewer image acquisitions and could be completed faster while maintaining a comparable treatment response.

Fusion of intravenous contrast-enhanced C-arm CT and pretreatment imaging for ablation margin assessment of liver tumors: A preliminary study

The aim of this preliminary study was to evaluate the feasibility of assessing ablation margins after radiofrequency ablation (RFA) of liver tumors from fusion images of post-treatment C-arm computed tomography (CT) images fused to pretreatment images. Five patients with liver tumors underwent RFA. Intravenous contrast-enhanced C-arm CT images were obtained for all patients immediately after RFA, and multi-detector CT (MDCT) images were obtained 3-7 days later. The C-arm CT and MDCT images were fused to pretreatment images using a multimodality image fusion software. The minimum ablation margins were assessed in the C-arm CT and MDCT fusion images. Ablation margins after RFA of liver tumors can be measured using intravenous contrast-enhanced C-arm CT images fused with pretreatment images. This technique has the potential for use in the intra-procedural assessment of liver tumor ablation.