Quantitative 4D transcatheter intraarterial perfusion MRI for standardizing angiographic chemoembolization endpoints

OBJECTIVE

The purpose of this study was to test the hypothesis that subjective angiographic endpoints during transarterial chemoembolization (TACE) of hepatocellular carcinoma are consistent and correlate with objective intraprocedural reductions in tumor perfusion determined with quantitative 4D transcatheter intraarterial perfusion MRI.

SUBJECTS AND METHODS

In this prospective study, 18 consecutively registered patients underwent TACE in a combined MRI-interventional radiology suite. Three board-certified interventional radiologists independently graded the angiographic endpoint of each procedure using a previously described subjective angiographic chemoembolization endpoint scale. A consensus endpoint rating was established for each patient. Patients underwent quantitative 4D transcatheter intraarterial perfusion MRI immediately before and after TACE, and mean whole tumor perfusion was calculated from the images. Consistency of subjective angiographic endpoint ratings between observers was evaluated with the intraclass correlation coefficient. The relation between the endpoint ratings and intraprocedural transcatheter intraarterial perfusion MRI changes was evaluated with the Spearman rank correlation coefficient.

RESULTS

The subjective angiographic chemoembolization endpoint rating scale showed very good consistency among all observers (intraclass correlation coefficient, 0.80). The consensus endpoint rating correlated significantly with both absolute (r = 0.54, p = 0.022) and percentage (r = 0.85, p < 0.001) reduction in intraprocedural perfusion.

CONCLUSION

The subjective angiographic chemoembolization endpoint rating scale shows very good consistency between raters and significantly correlates with objectively measured intraprocedural perfusion reductions during TACE. These results support the use of the scale as a standardized alternative method in quantitative 4D transcatheter intraarterial perfusion MRI to classify patients on the basis of embolic endpoints of TACE.

Radiographic response to locoregional therapy in hepatocellular carcinoma predicts patient survival times

BACKGROUND & AIMS

It is not clear whether survival times of patients with hepatocellular carcinoma (HCC) are associated with their response to therapy. We analyzed the association between tumor response and survival times of patients with HCC who were treated with locoregional therapies (LRTs) (chemoembolization and radioembolization).

METHODS

Patients received LRTs over a 9-year period (n = 463). Patients with metastases, portal venous thrombosis, or who had received transplants were excluded; 159 patients with Child-Pugh B7 or lower were analyzed. Response (based on European Association for the Study of the Liver [EASL] and World Health Organization [WHO] criteria) was associated with survival times using the landmark, risk-of-death, and Mantel-Byar methodologies. In a subanalysis, survival times of responders were compared with those of patients with stable disease and progressive disease.

RESULTS

Based on 6-month data, in landmark analysis, responders survived longer than nonresponders (based on EASL but not WHO criteria: P = .002 and .0694). The risk of death was also lower for responders (based on EASL but not WHO criteria: P = .0463 and .707). Landmark analysis of 12-month data showed that responders survived longer than nonresponders (P < .0001 and .004, based on EASL and WHO criteria, respectively). The risk of death was lower for responders (P = .0132 and .010, based on EASL and WHO criteria, respectively). By the Mantel-Byar method, responders had longer survival than nonresponders, based on EASL criteria (P < .0001; P = .596 with WHO criteria). In the subanalysis, responders lived longer than patients with stable disease or progressive disease.

CONCLUSIONS

Radiographic response to LRTs predicts survival time. EASL criteria for response more consistently predicted survival times than WHO criteria. The goal of LRT should be to achieve a radiologic response, rather than to stabilize disease.

Four-dimensional transcatheter intraarterial perfusion MRI monitoring of radiofrequency ablation of rabbit VX2 liver tumors

PURPOSE

To investigate the hypothesis that four-dimensional (4D) transcatheter intraarterial perfusion (TRIP) magnetic resonance imaging (MRI) can quantify immediate perfusion changes after radiofrequency (RF) ablation in rabbit VX2 liver tumors.

MATERIALS AND METHODS

Nine New Zealand White rabbits were used to surgically implant VX2 liver tumors. During ultrasound-guided RF ablation, tumors received either a true or sham ablation. After selective catheterization of the left hepatic artery under x-ray fluoroscopy, we acquired pre- and post-RF ablation 4D TRIP MR images using 3 mL of 2.5% intraarterial gadopentetate dimeglumine. Two regions-of-interest were drawn upon each tumor to generate signal-intensity time curves. Area under the curve (AUC) was calculated to provide semiquantitative perfusion measurements that were compared using a paired t-test (α = 0.05). Ablated tissue was visually confirmed on pathology using Evans blue dye.

RESULTS

Mean AUC perfusion of VX2 tumors for the true ablation group decreased by 92.0% (95% confidence interval [CI]: 83.3%-100%), from 1913 (95% CI: 1557, 2269) before RF ablation to 76.6 (95% CI: 18.4, 134.8) after RF ablation (a.u., P < 0.001). Sham-ablated tumors demonstrated no significant perfusion changes.

CONCLUSION

4D TRIP MRI can quantify liver tumor perfusion reductions in VX2 rabbits after RF ablation. This MRI technique can potentially be used to improve tumor response assessment at the time of RF ablation.

Abstract 4393: MRI-guided electroporation-mediated transarterial chemoembolization (E-TACE)

INTRODUCTION: Electropermeabilization involves the application of electrical pulses to increase cell membrane permeability; electrochemotherapy (ECT) takes advantage of this phenomenon to increase tumor uptake of drugs. The purpose of this study was to demonstrate the potential to use MRI for intra-procedural optimization of an electroporation-mediated TACE (E-TACE) approach intended to increase liver tumor drug uptake compared to transcatheter infusion alone.

MATERIALS & METHODS: Eight New Zealand White rabbits were used for our ACUC-approved experiments. Two VX2 tumor portions were implanted in the left medial hepatic lobe of each rabbit and a total of fourteen VX2 tumors were grown in these rabbits. Two tumor were grown in 6 rabbits (one as E-TACE treated tumor and other as control) and solitary larger tumors was grown in 2 rabbits (half of tumor treated with E-TACE, remaining half as control). Each rabbit was catheterized under DSA guidance with catheter placed in the left hepatic artery. Next, Baseline transcatheter intraarterial perfusion (TRIP) MRI (1.5T, Siemens Medical) was performed to generate tumor enhancement curves with an intra-arterial (IA) injection of Gd-DTPA. These contrast enhancement curves were generated to estimate time delay between IA bolus infusion and the period of maximum tumor uptake (for planning purposes to optimize delay interval, Td, between later IA Cisplatin infusion and application of electrical pulses). For E-TACE treated tumors (one tumor in each rabbit) bi-polar electrodes (1cm spacing) were inserted straddling the targeted tumor and 8 100μs 1300V pulses applied at the selected delay interval Td after the administration of Cisplatin solution through the catheter. Next, a post TRIP-MRI scan was performed to assess tumor perfusion alterations and treatment related tumor signal intensity changes. After allowing 3 hours for Cisplatin wash out, rabbits were euthanized and each tumor sectioned for ICP-MS measurement of intra-tumoral platinum concentrations.

RESULTS: ICP-MS results demonstrated significantly increased Cisplatin uptake in E-TACE treated tumors, increases of 6.0-fold compared to transcatheter infusion alone in six of the rabbits (n=6/8, p=0.017). Follow-up T2W-TSE images showed significant intra-tumoral T2W signal decreases in five rabbits (n=5/8) whereas no such signal changes were observed in other rabbits (two of which showed negligible Cisplatin uptake increases).

CONCLUSION: Our findings suggest that E-TACE may be effective for increasing tumor uptake of chemotherapeutic agents and that intra-procedural MRI should permit immediate confirmation of targeted drug delivery based upon signal changes only present in sufficiently treated tissues. Additional longitudinal studies are required to evaluate and compare treatment response between animals treated with E-TACE and those treated with conventional TACE approaches.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4393. doi:10.1158/1538-7445.AM2011-4393

Role of the EASL, RECIST, and WHO response guidelines alone or in combination for hepatocellular carcinoma: radiologic-pathologic correlation

BACKGROUND & AIMS

We sought to study receiver-operating characteristics (ROC) of the European Association for the Study of the Liver (EASL), Response Evaluation Criteria in Solid Tumors (RECIST), and World Health Organization (WHO) guidelines for assessing response following locoregional therapies individually and in various combinations.

METHODS

Eighty-one patients with hepatocellular carcinoma underwent liver explantation following locoregional therapies. Response was assessed using EASL, RECIST, and WHO. Kappa statistics were used to determine inter-method agreement. Uni/multivariate logistic regression analyses were performed to determine the variables predicting complete pathologic necrosis. Numerical values were assigned to the response classes: complete response=0, partial response=1, stable disease=2, and progressive disease=3. Various mathematical combinations of EASL and WHO were tested to calculate scores and their ROCs were studied using pathological examination of the explant as the gold standard.

RESULTS

Median times (95% CI) to the WHO, RECIST, and EASL responses were 5.3 (4-11.5), 5.6 (4-11.5), and 1.3months (1.2-1.5), respectively. Kappa coefficients for WHO/RECIST, WHO/EASL, and RECIST/EASL were 0.78, 0.28, and 0.31, respectively. EASL response demonstrated significant odds ratios for predicting complete pathologic necrosis on uni/multivariate analyses. Calculated areas under the ROC curves were: RECIST: 0.63, WHO: 0.68, EASL: 0.82, EASL+WHO: 0.82, EASL×WHO: 0.85, EASL+(2×WHO): 0.79 and (2×EASL)+WHO: 0.85. An EASL×WHO Score of ⩽1 had 90.2% sensitivity for predicting complete pathologic necrosis.

CONCLUSIONS

The product of WHO and EASL demonstrated better ROC than the individual guidelines for assessment of tumor response. EASL×WHO scoring system provides a simple and clinically applicable method of response assessment following locoregional therapies for hepatocellular carcinoma.

Radioembolization results in longer time-to-progression and reduced toxicity compared with chemoembolization in patients with hepatocellular carcinoma

BACKGROUND & AIMS

Chemoembolization is one of several standards of care treatment for hepatocellular carcinoma (HCC). Radioembolization with Yttrium-90 microspheres is a novel, transarterial approach to radiation therapy. We performed a comparative effectiveness analysis of these therapies in patients with HCC.

METHODS

We collected data from 463 patients who were treated with transarterial locoregional therapies (chemoembolization or radioembolization) over a 9-year period. We excluded patients who were not appropriate for comparison and analyzed data from 245 (122 who received chemoembolization and 123 who received radioembolization). Patients were followed for signs of toxicity; all underwent imaging analysis at baseline and follow-up time points. Overall survival was the primary outcome measure. Secondary outcomes included safety, response rate, and time-to-progression. Uni- and multivariate analyses were performed.

RESULTS

Abdominal pain and increased transaminase activity were more frequent following chemoembolization (P < .05). There was a trend that patients treated with radioembolization had a higher response rate than with chemoembolization (49% vs 36%, respectively, P = .104). Although time-to-progression was longer following radioembolization than chemoembolization (13.3 months vs 8.4 months, respectively, P = .046), median survival times were not statistically different (20.5 months vs 17.4 months, respectively, P = .232). Among patients with intermediate-stage disease, survival was similar between groups that received chemoembolization (17.5 months) and radioembolization (17.2 months, P = .42).

CONCLUSIONS

Patients with HCC treated by chemoembolization or radioembolization with Yttrium-90 microspheres had similar survival times. Radioembolization resulted in longer time-to-progression and less toxicity than chemoembolization. Post hoc analyses of sample size indicated that a randomized study with > 1000 patients would be required to establish equivalence of survival times between patients treated with these two therapies.

Quantitative 4D transcatheter intraarterial perfusion MRI for monitoring chemoembolization of hepatocellular carcinoma

PURPOSE

To develop a fully quantitative 4D transcatheter intraarterial perfusion (TRIP) magnetic resonance imaging (MRI) technique and prospectively test the hypothesis that quantitative 4D TRIP-MRI can be used clinically to monitor intraprocedural liver tumor perfusion reductions during transcatheter arterial chemoembolization (TACE).

MATERIALS AND METHODS

TACE was performed within an x-ray digital subtraction angiography (DSA)-MRI procedure suite in 16 patients with hepatocellular carcinoma. Quantitative 4D TRIP-MRI with targeted radiofrequency field mapping and dynamic longitudinal relaxation rate mapping was used to monitor changes in tumor perfusion during TACE. First-pass perfusion analysis was performed to produce intraprocedural blood flow (Frho) maps. Mean liver tumor perfusions before and after TACE were compared with a paired t-test (alpha = 0.05).

RESULTS

Perfusion reductions were successfully measured with quantitative 4D TRIP-MRI in 22 separate tumors during 18 treatment sessions. Mean tumor perfusion Frho decreased from 16.3 (95% confidence interval [CI]: 10.7-21.9) before TACE to 5.0 (95% CI: 3.5-6.5) (mL/min/100 mL) after TACE. Tumor perfusion reductions were statistically significant (P < 0.0005), with a mean absolute perfusion change of 11.4 (95% CI: 5.6-17.1) (mL/min/100 mL) and a mean percentage reduction of 61.0% (95% CI: 48.3%-73.6%).

CONCLUSION

Quantitative 4D TRIP-MRI can be successfully performed within clinical interventional settings to monitor intraprocedural changes in liver tumor perfusion during TACE.

Four-dimensional transcatheter intra-arterial perfusion MR imaging before and after uterine artery embolization in the rabbit VX2 tumor model

PURPOSE

To test the hypothesis that four-dimensional (4D) transcatheter intra-arterial perfusion (TRIP) MR imaging can measure uterine fibroid perfusion changes immediately before and after uterine artery embolization (UAE) in the rabbit VX2 tumor model.

MATERIALS AND METHODS

Eight VX2 uterine tumors were grown in six rabbits. After positioning a catheter within the uterine artery, we performed 4D TRIP-MRI measurements with 3-mL injections of 2.5% gadopentetate dimeglumine. We used a dynamic 3D spoiled-gradient echo sequence with in vivo B(1)-field correction for improved accuracy during perfusion quantification. We performed UAE using 1 mL of gelatin microspheres (2 x 10(6) particles; diameter 40-120 mum). Two regions-of-interest were drawn within each tumor upon perfusion maps. Functional embolic endpoints were reported as the mean percent reduction in fibroid tumor perfusion. Measurements before and after UAE were compared using paired t-tests (alpha = 0.05).

RESULTS

VX2 uterine tumor perfusion decreased significantly from 27.1 at baseline to 7.09 after UAE (mL/min/100 mL of tissue, P < 0.0001). Overall perfusion reduction was 76.3% (95% confidence interval: 66.3-86.3%).

CONCLUSION

Four-dimensional TRIP MRI can objectively quantify uterine fibroid perfusion reductions during UAE in VX2 rabbits. This technique could be used clinically to potentially determine an optimal embolic endpoint with the long-term goals of improving UAE success rates and minimizing procedure-related ischemic pain.

Chemoembolization for hepatocellular carcinoma: comprehensive imaging and survival analysis in a 172-patient cohort

PURPOSE

To determine comprehensive imaging and long-term survival outcome following chemoembolization for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

One hundred seventy-two patients with HCC treated with chemoembolization were studied retrospectively in an institutional review board approved protocol; this study was HIPAA compliant. Baseline laboratory and imaging characteristics were obtained. Clinical and laboratory toxicities following treatment were assessed. Imaging characteristics following chemoembolization were evaluated to determine response rates (size and necrosis) and time to progression (TTP). Survival from the time of first chemoembolization treatment was calculated. Subanalyses were performed by stratifying the population according to Child-Pugh, United Network for Organ Sharing, and Barcelona Clinic for Liver Cancer (BCLC) staging systems.

RESULTS

Cirrhosis was present in 157 patients (91%); portal hypertension was present in 139 patients (81%). Eleven patients (6%) had metastases at baseline. Portal vein thrombosis was present in 11 patients (6%). Fifty-five percent of patients experienced some form of toxicity following treatment; 21% developed grade 3 or 4 bilirubin toxicity. Post-chemoembolization response was seen in 31% and 64% of patients according to size and necrosis criteria, respectively. Median TTP was 7.9 months (95% confidence interval: 7.1, 9.4) but varied widely by stage. Median survival was significantly different between patients with BCLC stages A, B, and C disease (stage A, 40.0 months; B, 17.4 months; C, 6.3 months; P < .0001).

CONCLUSION

The determination of TTP and survival in patients with HCC is confounded by tumor biology and background cirrhosis; chemoembolization was shown to be a safe and effective therapy in patients with HCC.

Diffusion-weighted magnetic resonance imaging to predict response of hepatocellular carcinoma to chemoembolization

AIM: To investigate whether intra-procedural diffusion-weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during transcatheter arterial chemoembolization (TACE).

METHODS: Sixteen patients (15 male), aged 59 ± 11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable HCC in a hybrid magnetic resonance/interventional radiology suite. Anatomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm²) were performed on a 1.5-T unit. Tumor enhancement and apparent diffusion coefficient (ADC, mm²/s) values were assessed immediately before and at 1 and 3 mo after TACE. We calculated the percent change (PC) in ADC values at all time points. We compared follow-up ADC values to baseline values using a paired t test (α = 0.05).

RESULTS: The intra-procedural sensitivity, specificity, and positive and negative predictive values (%) for detecting a complete or partial 1-mo tumor response using ADC PC thresholds of ±5%, ±10%, and ±15% were 77, 67, 91, and 40; 54, 67, 88, and 25; and 46, 100, 100, and 30, respectively. There was no clear predictive value for the 3-mo follow-up. Compared to baseline, the immediate post-procedure and 1-mo mean ADC values both increased; the latter obtaining statistical significance (1.48 ± 0.29 mm²/s vs 1.65 ± 0.35 × 10^-3 mm²/s, P < 0.014).

CONCLUSION: Intra-procedural ADC changes of > 15% predicted 1-mo anatomical HCC response with the greatest accuracy, and can provide valuable feedback at the time of TACE.

Safety of yttrium-90 microsphere radioembolization in patients with biliary obstruction

PURPOSE

There are few data on radioembolization in the setting of biliary obstruction. The present study was performed to assess the safety of yttrium-90 ((90)Y) radioembolization in the setting of tumor-related biliary obstruction and total bilirubin levels of 2 mg/dL or lower.

MATERIALS AND METHODS

Twelve patients with liver tumors underwent 19 treatment sessions with (90)Y to the obstructed liver lobe or segment. Initial bilirubin level was 2 mg/dL or lower in all cases. Measured outcomes included pre- and posttreatment white blood cell (WBC) count, total bilirubin level, and alkaline phosphatase (ALP) level. Bilirubin toxicities and biliary complications were assessed according to Common Toxicity Criteria, version 3.0.

RESULTS

Lobar or segmental (90)Y was successful in all cases. Pre- and posttreatment median WBC counts (5.3 vs 5.3; P = .490), bilirubin levels (1.0 vs 1.1; P = .460), and ALP levels (195 vs 146; P = .712) showed no differences. One case of grade 3 bilirubin toxicity was noted in a patient with liver hilar nodal progression and subsequent biliary obstruction requiring external drainage. Complete resolution of biliary obstruction was seen after (90)Y treatment in one case of metastatic colorectal carcinoma at 1 month follow-up. No biliary complications (infection, sepsis, biliary necrosis, biloma formation, abscess development, or biliary stricture) were encountered in this cohort during an overall median follow-up time of 22.9 months.

CONCLUSIONS

The use of (90)Y glass microspheres demonstrated a good safety profile in the setting of tumor-related biliary obstruction in patients with normal or near-normal bilirubin levels in this series, without evidence of therapy-related progressive leukocytosis, bilirubin increase, or infectious or biliary complications after treatment.

Imaging response in the primary index lesion and clinical outcomes following transarterial locoregional therapy for hepatocellular carcinoma

CONTEXT

Response Evaluation Criteria in Solid Tumors (RECIST) (unidimensional), World Health Organization (WHO) (bidimensional), and European Association for Study of the Liver (EASL) (necrosis) guidelines are commonly used to assess response following therapy for hepatocellular carcinoma (HCC). No universally accepted standard exists.

OBJECTIVES

To evaluate intermethod agreement between these 3 imaging guidelines and to introduce the concept of the "primary index lesion" as a biomarker for response.

DESIGN, SETTING, AND PARTICIPANTS

Single-center comprehensive imaging analysis including 245 consecutive patients with HCC who were treated with chemoembolization or radioembolization between January 2000 and December 2008. Computed tomography and magnetic resonance imaging scans (N = 1065) were reviewed to assess response in the "primary index lesion," defined as the largest tumor targeted during first treatment.

MAIN OUTCOME MEASURES

Intermethod agreement (kappa statistics) between RECIST, WHO, and EASL guidelines response; correlation of WHO and EASL response in the primary index lesion with time to progression and survival.

RESULTS

Kappa coefficients were 0.86 (95% confidence interval [CI], 0.80-0.92) between the WHO and RECIST guidelines, 0.24 (95% CI, 0.16-0.33) between RECIST and EASL, and 0.28 (95% CI, 0.19-0.36) between WHO and EASL. Disease progressed in 96 patients; 113 died. The hazard ratio for time to progression in responders compared with nonresponders was 0.36 (95% CI, 0.23-0.57) for WHO, 0.38 (95% CI, 0.24-0.58) for RECIST, and 0.38 (95% CI, 0.22-0.64) for EASL. Hazard ratios for survival in responders compared with nonresponders in univariate and multivariate analyses were 0.46 (95% CI, 0.32-0.67) and 0.55 (95% CI, 0.35-0.84) for WHO and 0.36 (95% CI, 0.22-0.57) and 0.54 (95% CI, 0.34-0.85) for EASL. Hazard ratios for survival in responders vs nonresponders in patients with solitary and multifocal HCC were 0.39 (95% CI, 0.19-0.77) and 0.51 (95% CI, 0.32-0.82) for WHO and 0.26 (95% CI, 0.10-0.67) and 0.47 (95% CI, 0.28-0.79) for EASL.

CONCLUSIONS

Among a group of patients with HCC, agreement for classification of therapeutic response was high between the RECIST and WHO guidelines but low between each of these and EASL. Application of these methods to measure response in a primary index lesion resulted in statistically significant correlations with disease progression and survival.

Agreement between competing imaging measures of response of hepatocellular carcinoma to yttrium-90 radioembolization

PURPOSE

There are currently at least six major competing criteria used to determine response to yttrium-90 and other liver-directed therapies, including: (i) Response Evaluation Criteria in Solid Tumors (RECIST); (ii) World Health Organization (WHO), (iii) volumetric, (iv) two-dimensional (2D) European Association for the Study of the Liver (EASL), and (v) three-dimensional (3D) EASL criteria; and (vi) functional diffusion-weighted (DW) magnetic resonance (MR) imaging. This study evaluated agreement among these competing tumor response classification schemes based on quantitative measurements of tumor size, necrosis, and changes in water mobility.

MATERIALS AND METHODS

In this retrospective study, 20 patients with hepatocellular carcinoma (HCC) underwent (90)Y radioembolization. The patients' tumor burden before and 3-6 months after treatment was assessed with MR imaging. The percent change in size of tumors was used to classify patients into response categories. kappa and agreement statistics were used to compare concordance among the different criteria.

RESULTS

Conventional size criteria (RECIST, WHO, and volumetric) all had a substantial level of agreement (kappa = 0.76-0.78) when classifying patients into response categories. However, the conventional size criteria in relation to 2D or 3D EASL had only slight to moderate concurrence, with kappa statistics as low as 0.06. Two-dimensional EASL criteria and functional DW MR imaging resulted in the highest response rates, 55% (n = 11) and 75% (n = 15), respectively, whereas conventional size criteria produced lower response rates.

CONCLUSIONS

Classification of HCC response to (90)Y radioembolization is related to which of the competing criteria are used. It is recommended that anatomic imaging criteria be used as the primary method to determine response and functional imaging criteria be used as a complementary secondary method.

Radioembolization for hepatocellular carcinoma using Yttrium-90 microspheres: a comprehensive report of long-term outcomes

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) has limited treatment options; long-term outcomes following intra-arterial radiation are unknown. We assessed clinical outcomes of patients treated with intra-arterial yttrium-90 microspheres (Y90).

METHODS

Patients with HCC (n = 291) were treated with Y90 as part of a single-center, prospective, longitudinal cohort study. Toxicities were recorded using the Common Terminology Criteria version 3.0. Response rate and time to progression (TTP) were determined using World Health Organization (WHO) and European Association for the Study of the Liver (EASL) guidelines. Survival by stage was assessed. Univariate/multivariate analyses were performed.

RESULTS

A total of 526 treatments were administered (mean, 1.8; range, 1-5). Toxicities included fatigue (57%), pain (23%), and nausea/vomiting (20%); 19% exhibited grade 3/4 bilirubin toxicity. The 30-day mortality rate was 3%. Response rates were 42% and 57% based on WHO and EASL criteria, respectively. The overall TTP was 7.9 months (95% confidence interval, 6-10.3). Survival times differed between patients with Child-Pugh A and B disease (A, 17.2 months; B, 7.7 months; P = .002). Patients with Child-Pugh B disease who had portal vein thrombosis (PVT) survived 5.6 months (95% confidence interval, 4.5-6.7). Baseline age; sex; performance status; presence of portal hypertension; tumor distribution; levels of bilirubin, albumin, and alpha-fetoprotein; and WHO/EASL response rate predicted survival.

CONCLUSIONS

Patients with Child-Pugh A disease, with or without PVT, benefited most from treatment. Patients with Child-Pugh B disease who had PVT had poor outcomes. TTP and overall survival varied by patient stage at baseline. These data can be used to design future Y90 trials and to describe Y90 as a potential treatment option for patients with HCC.

Radiologic-pathologic correlation of hepatocellular carcinoma treated with chemoembolization

To correlate posttreatment radiologic and pathologic findings in patients who underwent transarterial chemoembolization before transplantation or resection. Thirty-five patients with postchemoembolization follow-up imaging underwent liver transplantation/resection. Pre- and posttreatment contrast-enhanced magnetic resonance imaging were used to evaluate radiologic findings. Imaging characteristics using World Health Organization (WHO) and European Association for the Study of the Liver (EASL) criteria after treatment were evaluated. Treated lesions were examined by pathology (gold standard) for the assessment of necrosis. Radiologic findings on magnetic resonance imaging were correlated to pathologic findings to assess the predictability by imaging of actual necrosis. Kappa (κ) statistics were used to determine intermethod agreement between WHO and EASL criteria. Fourteen (40%) of 35 lesions had biopsy-proven hepatocellular carcinoma. Thirteen (37%) of 35 target lesions showed complete pathologic necrosis. Complete pathologic necrosis was seen in 35% of lesions with pretreatment size <3 cm. Complete pathologic necrosis was seen in 1 (100%) of 1, 6 (67%) of 9, 6 (33%) of 18, and 0 (0%) of 7 of the lesions that exhibited complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD) by WHO criteria, respectively. Complete pathologic necrosis was seen in 9 (82%) of 11, 4 (36%) of 11, 0 (0%) of 8, and 0 (0%) of 5 of the lesions that showed CR, PR, SD, or PD by EASL criteria, respectively. EASL CR and WHO response were shown to have ≥85% specificity for predicting complete pathologic necrosis. The κ coefficient for agreement between WHO and EASL was 0.29. EASL and WHO criteria had minimal intermethod agreement. EASL CR and WHO response were able to predict pathologic necrosis.

Yttrium-90 radioembolization for liver malignancies: prognostic factors associated with survival

PURPOSE

To identify key prognostic clinical and imaging variables in patients undergoing yttrium-90 radioembolization ((90)Y) for liver malignancies.

MATERIALS AND METHODS

Patients with liver malignancies that progressed despite standard-of-care therapy were treated with (90)Y from 2002 to 2006. Baseline functional status, laboratory values, and diagnostic imaging were assessed before therapy. Imaging follow-up was performed 1 month after treatment and subsequently at 3-month intervals. Patients were followed for survival from the time of their first (90)Y treatment.

RESULTS

Patients with follow-up imaging after radioembolization (N = 130) were included in this analysis. Primary malignancies included colon, neuroendocrine, and others. The following clinical variables had a significant effect on survival on multivariate analysis: Eastern Cooperative Oncology Group (ECOG) performance status (PS) greater than 0 (hazard ratio [HR], 7.98; 95% CI, 3.98-16), hepatic tumor burden of 51%-75% (HR, 2.46; 95% CI, 1.01-6.02), bilirubin level greater than 1.3 mg/dL (HR, 2.60; 95% CI, 1.27-5.34), hepatic metastases from breast cancer (HR, 2.51; 95% CI, 1.13-5.61), response on imaging based on World Health Organization (WHO) criteria (HR, 0.48; 95% CI, 0.24-0.94), and lymphocyte depression (HR, 0.56; 95% CI, 0.31-0.96). Among patients with colorectal cancer metastases to the liver, the HR for survival on univariate analysis for responders compared with nonresponders (per WHO criteria) was 0.26 (95% CI, 0.10-0.69).

CONCLUSIONS

Cancer-related symptoms (ie, ECOG PS > 0), hepatic tumor burden greater than 50%, increased bilirubin levels, and hepatic metastases from breast cancer were found to be negative prognostic factors. Tumor response to therapy and lymphocyte depression were associated with favorable prognosis. Additionally, WHO response was identified to be a favorable prognostic factor in patients with colorectal cancer metastases. These findings may be useful when counseling patients regarding prognosis of their hepatic disease.

How to interpret thyroid biopsy results: a three-year retrospective interventional radiology experience

Results of thyroid biopsy determine whether thyroid nodule resection is appropriate and the extent of thyroid surgery. At our institution we use 20/22-gauge core biopsy (CBx) in conjunction with fine-needle aspiration (FNA) to decrease the number of passes and improve adequacy. Occasionally, both ultrasound (US)-guided FNA and CBx yield unsatisfactory specimens. To justify clinical recommendations for these unsatisfactory thyroid biopsies, we compare rates of malignancy at surgical resection for unsatisfactory biopsy results against definitive biopsy results. We retrospectively reviewed a database of 1979 patients who had a total of 2677 FNA and 663 CBx performed by experienced interventional radiologists under US guidance from 2003 to 2006 at a tertiary-care academic center. In 451 patients who had surgery following biopsy, Fisher's exact test was used to compare surgical malignancy rates between unsatisfactory and malignant biopsy cohorts as well as between unsatisfactory and benign biopsy cohorts. We defined statistical significance at P = 0.05. We reported an overall unsatisfactory thyroid biopsy rate of 3.7% (100/2677). A statistically significant higher rate of surgically proven malignancies was found in malignant biopsy patients compared to unsatisfactory biopsy patients (P = 0.0001). The incidence of surgically proven malignancy in unsatisfactory biopsy patients was not significantly different from that in benign biopsy patients (P = 0.8625). In conclusion, an extremely low incidence of malignancy was associated with both benign and unsatisfactory thyroid biopsy results. The difference in incidence between these two groups was not statistically significant. Therefore, patients with unsatisfactory biopsy specimens can be reassured and counseled accordingly.

The role of tumor vascularity in predicting survival after yttrium-90 radioembolization for liver metastases

PURPOSE

It is unclear what role pretreatment tumor vascularity plays in determining outcomes after yttrium-90 radioembolization. A hypothesis was tested that radiographic vascularity of a tumor does not affect patient survival.

MATERIALS AND METHODS

In this two-institution retrospective study, 137 patients with metastatic liver disease underwent (90)Y radioembolization. Primary sites were categorized as colon, neuroendocrine, and other. All patients underwent triphasic contrast-enhanced computed tomography (CT) or magnetic resonance imaging, as well as detailed hepatic angiography. Two board-certified interventional radiologists interpreted all images and evaluated them for the presence of enhancement. Median survival times, as well as 1- and 2-year survival rates, were compared between patients with hypervascular and hypovascular tumors on (i) cross-sectional imaging and (ii) angiography with use of the log-rank statistic (alpha = 0.05).

RESULTS

On angiography, 108 patients had hypervascular tumors and 29 had hypovascular tumors. Median survival times for the two subgroups were 300 days and 261 days, respectively (P = .95). On CT, 24 patients had hypervascular tumors and 113 had hypovascular tumors. Median survival times for these subgroups were 306 days and 284 days, respectively (P = .67). Eighty-four patients' tumors that were hypovascular on CT were hypervascular on angiography. There were no statistical differences in survival between patients with hypervascular and hypovascular tumors, regardless if vascularity was defined based on CT or angiography.

CONCLUSIONS

Radiographic vascular appearance of liver tumors, regardless of imaging modality, does not affect survival after radioembolization. Therefore, hypovascular tumors should not be considered contraindicated for radioembolization.

Alpha-fetoprotein response after locoregional therapy for hepatocellular carcinoma: oncologic marker of radiologic response, progression, and survival

PURPOSE

Alpha-fetoprotein (AFP) is considered to be an indicator of tumor activity in hepatocellular carcinoma (HCC). We present a novel correlation of AFP response to radiologic response, time-to-progression (TTP), progression-free survival (PFS), and overall survival (OS) in patients treated with locoregional therapies.

PATIENTS AND METHODS

Four hundred sixty-three patients with HCC were treated with chemoembolization or radioembolization at our institution. One hundred twenty-five patients with baseline AFP higher than 200 ng/mL were studied for this analysis. AFP response was defined as more than 50% decrease from baseline. One hundred nineteen patients with follow-up imaging were studied for the AFP imaging correlation analysis. AFP response was correlated to radiologic response, TTP, PFS, and OS. Multivariate analyses were performed.

RESULTS

Eighty-one patients (65%) showed AFP response. AFP response was seen in 26 (55%) of 47 and 55 (70%) of 78 of patients treated with chemoembolization and radioembolization, respectively (P = .12). WHO response was seen in 41 (53%) of 77 and 10 (24%) of 42 of AFP responders and nonresponders, respectively (P = .002). The hazard ratio (HR) for TTP in AFP nonresponders compared with responders was 2.8 (95% CI, 1.5 to 5.1). The HR for PFS was 4.2 (95% CI, 2.4 to 7.2) in AFP nonresponders compared with responders. The HR for OS in AFP nonresponders compared with responders was 5.5 (95% CI, 3.1 to 9.9) and 2.7 (95% CI, 1.6 to 4.6) on univariate and multivariate analyses, respectively.

CONCLUSION

The data presented support the use of AFP response seen after locoregional therapy as an ancillary method of assessing tumor response and survival, as well as an early objective screening tool for progression by imaging.

A comparative analysis of transarterial downstaging for hepatocellular carcinoma: chemoembolization versus radioembolization

Chemoembolization and other ablative therapies are routinely utilized in downstaging from United Network for Organ Sharing (UNOS) T3 to T2, thus potentially making patients transplant candidates under the UNOS model for end-stage liver disease (MELD) upgrade for hepatocellular carcinoma (HCC). This study was undertaken to compare the downstaging efficacy of transarterial chemoembolization (TACE) versus transarterial radioembolization. Eighty-six patients were treated with either TACE (n = 43) or transarterial radioembolization with Yttrium-90 microspheres (TARE-Y90; n = 43). Median tumor size was similar (TACE: 5.7 cm, TARE-Y90: 5.6 cm). Partial response rates favored TARE-Y90 versus TACE (61% vs. 37%). Downstaging to UNOS T2 was achieved in 31% of TACE and 58% of TARE-Y90 patients. Time to progression according to UNOS criteria was similar for both groups (18.2 months for TACE vs. 33.3 months for TARE-Y90, p = 0.098). Event-free survival was significantly greater for TARE-Y90 than TACE (17.7 vs. 7.1 months, p = 0.0017). Overall survival favored TARE-Y90 compared to TACE (censored 35.7/18.7 months; p = 0.18; uncensored 41.6/19.2 months; p = 0.008). In conclusion, TARE-Y90 appears to outperform TACE for downstaging HCC from UNOS T3 to T2.

Development of a VX2 pancreatic cancer model in rabbits: a pilot study

PURPOSE

An animal model of pancreatic cancer that is large enough to permit imaging and catheterization would be desirable for interventional radiologists to develop novel therapies for pancreatic cancer. The purpose of this study was to test the hypothesis that the VX2 rabbit model of pancreatic cancer could be developed as a suitable platform to test future interventional therapies.

MATERIALS AND METHODS

The authors implanted and grew three pancreatic VX2 tumors per rabbit in six rabbits. Magnetic resonance (MR) imaging was performed at 2 weeks to confirm tumor growth. At 3 weeks, the authors selectively catheterized the gastroduodenal artery under guidance of x-ray digital subtraction angiography (DSA). T2-weighted anatomic imaging, diffusion-weighted MR imaging, and transcatheter intraarterial perfusion (TRIP) MR imaging were then performed. After imaging, tumors were confirmed at necropsy and histopathologically. Tumor sizes at 2 and 3 weeks were compared with a paired t test (P = .05).

RESULTS

VX2 pancreatic tumors were grown in all six rabbits. The difference between tumor sizes at 2 and 3 weeks (1.29 cm +/- 0.39 vs 1.91 cm +/- 0.50, respectively) was significant (P < .001). All tumors were confirmed to be located within pancreatic tissue via histopathologic analysis. DSA and TRIP MR imaging were successful in five rabbits. Diffusion-weighted and anatomic MR imaging were successful in all six rabbits.

CONCLUSIONS

The VX2 rabbit model of pancreatic cancer is feasible, as verified by imaging and pathologic correlation, and may be a suitable platform to test future interventional therapies.

A comparative analysis of transarterial downstaging for hepatocellular carcinoma: chemoembolization versus radioembolization

Chemoembolization and other ablative therapies are routinely utilized in downstaging from United Network for Organ Sharing (UNOS) T3 to T2, thus potentially making patients transplant candidates under the UNOS model for end-stage liver disease (MELD) upgrade for hepatocellular carcinoma (HCC). This study was undertaken to compare the downstaging efficacy of transarterial chemoembolization (TACE) versus transarterial radioembolization. Eighty-six patients were treated with either TACE (n = 43) or transarterial radioembolization with Yttrium-90 microspheres (TARE-Y90; n = 43). Median tumor size was similar (TACE: 5.7 cm, TARE-Y90: 5.6 cm). Partial response rates favored TARE-Y90 versus TACE (61% vs. 37%). Downstaging to UNOS T2 was achieved in 31% of TACE and 58% of TARE-Y90 patients. Time to progression according to UNOS criteria was similar for both groups (18.2 months for TACE vs. 33.3 months for TARE-Y90, p = 0.098). Event-free survival was significantly greater for TARE-Y90 than TACE (17.7 vs. 7.1 months, p = 0.0017). Overall survival favored TARE-Y90 compared to TACE (censored 35.7/18.7 months; p = 0.18; uncensored 41.6/19.2 months; p = 0.008). In conclusion, TARE-Y90 appears to outperform TACE for downstaging HCC from UNOS T3 to T2.

Radioembolization of colorectal hepatic metastases using yttrium-90 microspheres

BACKGROUND

: The objective of the current study was to determine the safety and efficacy of Yttrium-90 (Y90) microsphere treatment in patients with liver-dominant colorectal metastases.

METHODS

: Seventy-two patients with unresectable hepatic colorectal metastases were treated at a targeted absorbed dose of 120 Gray (Gy). Safety and toxicity were assessed using version 3 of the National Cancer Institute Common Terminology Criteria. Response was assessed by anatomic imaging and positron emission tomography (PET). Survival from the diagnosis of hepatic metastases and first treatment were estimated using the Kaplan-Meier method. Substratification analyses were performed.

RESULTS

: The median dose delivered was 118 Gy. Treatment-related toxicities included fatigue (61%), nausea (21%), and abdominal pain (25%). Grade 3 and 4 bilirubin toxicities were observed in 9 of 72 patients (12.6%). The tumor response rate was 40.3%. The median time to hepatic progression was 15.4 months, and the median response duration was 15 months. The PET response rate was 77%. Overall survival from the first Y90 treatment was 14.5 months. Tumor replacement (< or =25% vs >25%) was associated with significantly greater median survival (18.7 months vs 5.2 months). The presence of extrahepatic disease was associated negatively with overall survival (7.9 months vs 21 months). Overall survival from the date of initial hepatic metastases was 34.6 months. A subset analysis of patients who had an Eastern Cooperative Oncology Group performance status of 0 demonstrated a median survival of 42.8 months and 23.5 months from the time of hepatic metastases and Y90 treatment, respectively.

CONCLUSIONS

: Y90 liver therapy appears to provide sustained disease stabilization with acceptable toxicity. Asymptomatic patients with preserved liver function at the time of Y90 appeared to benefit most from treatment. Cancer 2009. (c) 2009 American Cancer Society.

Radiation lobectomy: preliminary findings of hepatic volumetric response to lobar yttrium-90 radioembolization

PURPOSE

To describe volumetric changes of "radiation lobectomy," a manifestation of hepatic parenchymal response to lobar (90)Y microsphere radioembolization.

METHODS

Twenty patients exhibiting this phenomenon were identified. Pre- and posttreatment absolute right and left hepatic lobar volume (HLV), relative HLV (rHLV = HLV/total liver volume), and degree of lobar atrophy (DA) or hypertrophy (DH) (DA or DH = |posttreatment rHLV - pretreatment rHLV|) were determined. Laboratory toxicities, tumor response, and patient survival were also assessed.

RESULTS

Twenty patients with primary (HCC, n = 17; peripheral cholangiocarcinoma, n = 3) liver malignancies demonstrated findings of radiation lobectomy. Initial absolute right and left HLV was 955 cm(3) (range 644-1,842 cm(3), rHLV = 57%) and 719 cm(3) (range 328-1,387 cm(3), rHLV = 43%), respectively. Following (90)Y, absolute right HLV decreased to 460 cm(3) (range 185-948 cm(3), 52% reduction, rHLV = 31%, DA = 26%, P < 0.0001), while absolute left HLV increased to 1,004 cm(3) (range 560-1,558 cm(3), 40% increase, rHLV = 69%, DH = 26%, P < 0.0001). No grade 3 or 4 bilirubin toxicities were encountered. Tumor response ranged from 55% to 70% by size criteria. Forty-six percent 5-year survival was achieved in HCC patients.

CONCLUSIONS

Radiation lobectomy following (90)Y radioembolization of right lobe tumors manifests extensive contralateral lobar hypertrophy, high response rates, and prolonged survival. This phenomenon was noted in 6.4% (20/315) of the entire cohort and 19.8% (20/101) of patients with unilobar right lobe tumors. Further investigation is necessary to determine contributing factors that may predict this effect.

Radiologic-pathologic correlation of hepatocellular carcinoma treated with internal radiation using yttrium-90 microspheres

We present the correlation between radiologic and pathologic findings in HCC patients who underwent radioembolization with yttrium-90 ((90)Y) microspheres prior to resection or transplantation. Thirty-five patients with a total of 38 lesions who underwent liver explantation after (90)Y radioembolization were studied. Imaging surrogates following treatment were evaluated; the explants were examined for assessment of necrosis by pathology. The correlation between radiologic and histologic findings of the treated lesions was analyzed. Twenty-three of 38 (61%) target lesions showed complete pathologic necrosis. All target lesions demonstrated some degree of histologic necrosis at explant. Complete histologic necrosis was seen in 89% of lesions with pretreatment size <3 cm. Complete pathologic necrosis was seen in 100%, 78%, and 93% of the lesions that were shown to have complete response by European Association for the Study of the Liver (EASL) necrosis criteria, partial response by World Health Organizaton (WHO) criteria, or thin rim enhancement on posttreatment imaging, respectively. In contrast, complete pathologic necrosis was seen in only 52% and 38% of the lesions that showed partial response by EASL criteria and peripheral nodular enhancement, respectively.

CONCLUSION

Post-radioembolization imaging findings of response by EASL and WHO criteria are predictive of the degree of pathologic necrosis. Rim enhancement was an imaging characteristic that correlated well with histologic necrosis.

Comparison of hypoxia-inducible factor-1alpha expression before and after transcatheter arterial embolization in rabbit VX2 liver tumors

PURPOSE

To test the hypothesis that transcatheter arterial embolization (TAE) induces expression of hypoxia-inducible factor-1alpha (HIF-1alpha) within the same rabbit VX2 liver tumor.

MATERIALS AND METHODS

Seven VX2 tumors were grown in the livers of five New Zealand white rabbits. Ultrasonography-guided biopsy was performed before and 10 minutes after TAE in all tumors. Pre- and post-TAE tumor biopsy specimens along with post-TAE whole liver tumor sections were stained with HIF-1alpha antibody and analyzed for percentage of HIF-1alpha-positive nuclei by using a spectral unmixing system mounted on a high-powered microscope. Statistical data comparisons were performed with the Wilcoxon signed-rank test (alpha = 0.05).

RESULTS

TAE of liver tumors resulted in a statistically significant increase in the mean percentage of HIF-1alpha expression. The mean percentage of HIF-1alpha-positive stained nuclei increased from 23% +/- 3.5 in pre-TAE biopsy specimens to 41% +/- 8.7 in post-TAE biopsy specimens (P < .02). The increase was even more significant when the mean percentage of HIF-1alpha-positive stained nuclei from the same pre-TAE biopsy specimens was compared with sections from post-TAE whole tumor specimens (60% +/- 8.9, P < .02).

CONCLUSIONS

The results of this study revealed that hypoxia caused by TAE of VX2 liver tumors activates HIF-1alpha, a transcription factor that in turn regulates other pro-angiogenic factors.

Treatment of unresectable cholangiocarcinoma using yttrium-90 microspheres: results from a pilot study

BACKGROUND

The objective of this report was to present data from an open-label cohort study in which patients with intrahepatic cholangiocarcinoma (ICC) underwent radioembolization with yttrium-90 ((90)Y) microspheres.

METHODS

Twenty-four patients with histologically proven ICC were treated. The planned target dose was 120 Gray. Patients were stratified according to Eastern Cooperation Oncology Group (ECOG) performance status, tumor morphology (infiltrative vs peripheral), tumor distribution (solitary vs multifocal), and the presence or absence of portal vein thrombosis (PVT). Before and after the procedure, the following variables were assessed: 1) biochemical and clinical toxicity, 2) imaging (computed tomography/magnetic resonance imaging) response according to World Health Organization and European Association for the Study of Liver Disease (EASL) criteria, and 3) median survival after the first treatment using Kaplan-Meier methodology.

RESULTS

In total, 48 (90)Y treatments were administered to hepatic segments or lobes. Fatigue and transient abdominal pain were reported in 18 patients (75%) and 10 patients (42%), respectively. One patient (4%) developed grade 3 bilirubin toxicity. One patient (4%) developed a treatment-related gastroduodenal ulcer. On imaging follow-up of 22 patients, tumors demonstrated a partial response in 6 patients (27%), stable disease in 15 patients (68%), and progressive disease in 1 patient (5%). By using EASL guidelines, 17 patients (77%) showed >50% tumor necrosis on imaging follow-up. Two patients (9%) demonstrated 100% tumor necrosis. The median overall survival for the entire cohort (n = 24) was 14.9 months. The median survival for patients with an ECOG performance status of 0, 1, and 2 was 31.8 months, 6.1 months, and 1 month, respectively (P < .0001); the median survival for patients without and with PVT was 31.8 months and 5.7 months, respectively (P = .0003); and the median survival for patients with peripheral versus periductal-infiltrative tumors was 31.8 months and 5.7 months, respectively (P = .0005).

CONCLUSIONS

Radioembolization with (90)Y may be a therapeutic option for the treatment of unresectable ICC. Cancer 2008.

MR tracking of iron-labeled glass radioembolization microspheres during transcatheter delivery to rabbit VX2 liver tumors: feasibility study

PURPOSE

To prospectively test the hypothesis that iron labeling of radioembolization microspheres permits their visualization by using magnetic resonance (MR) imaging for in vivo tracking during transcatheter delivery to liver tumors.

MATERIALS AND METHODS

All experiments were approved by the Institutional Animal Care and Use Committee. Phantom studies were performed to quantify microsphere relaxivity and volume susceptibility properties and compare image contrast patterns resulting from aggregate deposition of unlabeled and iron-labeled microspheres. In seven rabbits in which nine VX2 liver tumors were implanted, T2*-weighted gradient-echo (GRE) MR images with negative image contrast (NC), white-marker (WM) GRE images with positive image contrast (PC), and on-resonance water-suppression turbo spin-echo (SE) images with PC were obtained before and after catheter-directed administration of microspheres into the hepatic artery. During each injection, serial GRE acquisitions were performed for real-time visualization of microsphere delivery. Contrast-to-noise ratios (CNRs) were measured between regions of microsphere accumulation and regions of normal liver parenchyma that demonstrated no apparent microsphere accumulation. Pre- and postinjection CNR measurements at identical spatial positions were compared by using paired t test (alpha = .05).

RESULTS

Conventional microspheres did not produce detectable image contrast in phantoms. Iron-labeled microspheres produced susceptibility-induced dipole patterns with spatial extent of image contrast increasing with increasing microsphere dose. Real-time image series depicted both preferential delivery to tumor tissues and nontargeted delivery to adjacent organs. T2*-weighted GRE, WM GRE, and on-resonance water-suppression turbo SE each permitted in vivo visualization of the microsphere deposition, with postinjection CNR values (mean, 14.29 +/- 3.98 [standard deviation], 1.87 +/- 0.93, and 19.30 +/- 8.72, respectively) significantly greater than corresponding preinjection CNR values (mean, 2.02 +/- 4.65, 0.02 +/- 0.27, 0.85 +/- 2.65, respectively) (P < .05).

CONCLUSION

Microsphere tracking during radioembolization may permit real-time verification of delivery and detection of extrahepatic shunting.

Uterine artery embolization: a treatment option for symptomatic fibroids in postmenopausal women

The authors tested the hypothesis that UAE is an effective treatment option in postmenopausal women with fibroid-related bulk symptoms. The authors retrospectively reviewed a prospectively acquired HI-IQ database. Between 2001 and 2004, 24 women with an average age of 52 years meeting the Stages of Reproductive Aging Workshop criteria for menopause underwent UAE for fibroid-related bulk symptoms. All patients underwent preprocedural gadolinium-enhanced magnetic resonance (MR) imaging to confirm the presence of fibroid disease and exclude other pathology. These patients were followed at 1-, 3-, 6-, 12-, and 24-month intervals to assess their clinical response to therapy. Clinical success was defined as a qualitative reduction in bulk symptoms. Postprocedural gadolinium-enhanced MR imaging was performed routinely between 3 and 6 months and at 12 or 24 months, if indicated. Technical success was achieved in 24 of 24 (100%) patients. The follow-up period ranged from 1 to 24 months with an average of 9 months. Clinical success was achieved in 22 of 24 (92%) women. There were no major complications in any of the patients. Mean uterine volume was reduced by 564 cc (P < .0001). Mean dominant uterine fibroid volume was reduced by 180 cm(3) (P = .0015). Uterine artery embolization is a viable treatment option in carefully selected postmenopausal women with fibroid-related bulk symptoms.

Rabbit VX2 tumors as an animal model of uterine fibroids and for uterine artery embolization

PURPOSE

To determine the suitability of the rabbit VX2 tumor animal model for uterine fibroids and uterine artery embolization (UAE).

MATERIALS AND METHODS

The authors implanted and grew one uterine VX2 tumor per rabbit in six rabbits. UAE was performed by using 100-300 microm embolic particles and confirmed with x-ray digital subtraction angiography, magnetic resonance (MR) imaging, and necropsy. Unenhanced and contrast medium-enhanced MR images of VX2 tumors were obtained before and after UAE. Relative MR signal-to noise-ratio (SNR) was measured in the uterine VX2 tumor and in normal uterine tissue before and after UAE and compared by using a paired t-test (P = .05).

RESULTS

VX2 uterine tumors were successfully grown, and both VX2 tumor presence in the uterus and UAE were seen angiographically and confirmed with necropsy in all six rabbits. Statistically significant reductions in relative SNRs were measured in tumors (SNR before UAE, 15.3 +/- 5.15; SNR after UAE, 3.84 +/- 3.94; P < .0001). No statistically significant decrease in SNR was measured in normal uterine tissue before and after UAE (P = .63 for the right uterine horn and P = .93 for the left uterine horn).

CONCLUSION

Rabbit VX2 uterine tumors may be a suitable animal model of uterine fibroids and UAE.

Radiology resident interpretations of on-call imaging studies: the incidence of major discrepancies

RATIONALE AND OBJECTIVES

To determine the incidence of radiology resident preliminary interpretation errors for plain film, body computed tomography, and neuroradiology (neuro)computed tomographic examinations read on call.

MATERIALS AND METHODS

We retrospectively reviewed the data in a prospectively acquired resident quality assurance (QA) database dating between January 2000 and March 2007. The database comprises all imaging studies initially interpreted by an on-call resident and later reviewed by a board-certified attending radiologist who determined the level of discrepancy between the two interpretations according to a graded scale from 0 (no discrepancy) to 3 (major discrepancy). We reviewed the data with respect to resident training level, imaging modality, and variance level. Statistical analysis was performed with chi2 test, alpha=0.05. We compared our results with other published series studying resident and attending accuracy.

RESULTS

A total of 141,381 cases were entered into the database during the review period. Of all examinations, 95.7% had zero variance, 3.3% minor variance, and 1.0% major variance. There was a slight, statistically significant increase in overall accuracy with increased resident year from 95.4% of examinations read by first-year residents (R1s) to 96.1% by fourth-year resident (R4s) (P<.0001). Overall percentages of exams with major discrepancies were 1.0% for R1s, 1.1% for second-year residents, 1.0% for third-year residents, and 0.98% for R4s.

CONCLUSIONS

The majority of preliminary resident interpretations are highly accurate. The incidence of major discrepancies is extremely low and similar, even with R1s, to that of attending radiologists published in other studies. A slight, statistically significant decrease in the error rate is detectable as residents gain experience throughout the 4 years of residency.

Comparison of two different methods for inoculating VX2 tumors in rabbit livers and hind limbs

PURPOSE

To compare two methods to (a) propagate VX2 cell strain in rabbit hind limbs and (b) inoculate liver parenchymal tumors in rabbits.

MATERIALS AND METHODS

One hundred forty-two New Zealand white rabbits were used for this study (60 with hind limb tumor [donors] and 82 with liver tumors [recipients]). In the donor group, nine rabbits received frozen VX2 cell suspension and 51 were injected with freshly prepared VX2 cell suspension. In the recipient group, 32 rabbits were injected with VX2 tumor cells and 50 were implanted with a small tumor fragment in the liver parenchyma. Success rates in terms of tumor growth were compared by using chi(2) or Fisher exact tests, with alpha = .05.

RESULTS

Hind limb and liver tumors were successfully grown in 48 of the 60 rabbits in the donor group (80%) and 57 of the 82 rabbits in the recipient group (70%). The success rate of growing hind limb tumors increased from 33% (three of nine rabbits) to 88% (45 of 51 rabbits) when fresh VX2 cells instead of frozen were injected percutaneously (P < .0011). Similarly, the success rate for VX2 liver tumors almost doubled from 47% (15 of 32 rabbits) to 84% (42 of 50 rabbits) when a tumor fragment instead of VX2 cell suspension was used (P < .00036). This also significantly reduced the frequency of metastasis (P < .005).

CONCLUSIONS

The authors recommend (a) the use of fresh VX2 cell suspension for percutaneous injection in the hind limbs of rabbits to maintain the VX2 cell strain and (b) the surgical implantation of freshly harvested VX2 tumor fragment into the liver parenchyma to establish liver tumors.

Transcatheter intraarterial perfusion: MR monitoring of chemoembolization for hepatocellular carcinoma--feasibility of initial clinical translation

PURPOSE

To prospectively test the hypothesis that intraprocedural transcatheter intraarterial perfusion (TRIP) magnetic resonance (MR) imaging can be used to successfully measure reductions in perfusion to the targeted hepatocellular carcinoma (HCC) and the adjacent surrounding liver tissue during MR-interventional radiology (IR)-monitored transcatheter arterial chemoembolization (TACE).

MATERIALS AND METHODS

This HIPAA-compliant prospective study was approved by the institutional review board. An MR-IR unit was used to perform TACE in 10 patients with HCC (seven male, three female; eight younger than 69 years, two older than 69 years). Intraprocedural reductions in tumor perfusion before and after TACE were monitored with TRIP MR imaging. Time-signal intensity curves were derived, and semiquantitative spatially resolved area under the time-signal intensity curve maps of tumor perfusion before and after TACE were produced. Mean perfusion values before and after TACE for liver tumors and adjacent liver tissue were compared by using a mixed-model analysis, with alpha = .05.

RESULTS

Perfusion reductions were measured successfully with TRIP MR imaging in 18 separate tumors during 13 treatment sessions. Perfusion maps showed significant perfusion reductions for tumors (P < .013) but not for adjacent nontumorous liver tissue (P = .21). For tumors, the mean perfusion value was 193 arbitrary units (AU) +/- 223 (standard deviation) before TACE and 45.3 AU +/- 91.9 after TACE, with a mean reduction in baseline perfusion of 74.6% +/- 24.8. For adjacent liver tissue, the mean perfusion value was 124 AU +/- 93.5 before TACE and 93.2 AU +/- 72.3 after TACE, with a mean reduction in baseline perfusion of 24.2% +/- 14.5.

CONCLUSION

TRIP MR imaging can be used to detect intraprocedural changes in perfusion to HCC and surrounding liver parenchyma during MR-IR-monitored TACE.

Radioembolization for the treatment of unresectable hepatocellular carcinoma: A clinical review

Hepatocellular carcinoma (HCC) is the sixth most common cancer in the world. The majority of patients with HCC present with unresectable disease. These patients have historically had limited treatment options secondary to HCC demonstrating chemoresistance to the currently available systemic therapies. Additionally, normal liver parenchyma has shown intolerance to tumoricidal radiation doses, limiting the use of external beam radiation. Because of these limitations, novel percutaneous liver-directed therapies have emerged. The targeted infusion of radioactive microspheres (radioembolization) represents one such therapy. Radioembolization is a minimally invasive transcatheter therapy through which radioactive microspheres are infused into the hepatic arteries that supply tumor. Once infused, these microspheres traverse the hepatic vascular plexus and selectively implant within the tumor arterioles. Embedded within the arterioles, the ⁹⁰Y impregnated microspheres emit high energy and low penetrating radiation doses selectively to the tumor. Radioembolization has recently shown promise for the treatment of patients with unresectable HCC. The objective of this review article is to highlight two currently available radioembolic devices (⁹⁰Y, ¹⁸⁸Rh) and provide the reader with a recent review of the literature.

Unresectable chemorefractory liver metastases: radioembolization with 90Y microspheres--safety, efficacy, and survival

PURPOSE

To prospectively evaluate the safety, efficacy, and survival of patients with chemorefractory liver metastases who have been treated with yttrium 90 ((90)Y) glass microspheres.

MATERIALS AND METHODS

Institutional review boards from two institutions approved the HIPAA-compliant study; all patients provided informed consent. One hundred thirty-seven patients underwent 225 administrations of (90)Y microspheres by using intraarterial infusion. Primary sites (origins) included colon, breast, neuroendocrine, pancreas, lung, cholangiocarcinoma, melanoma, renal, esophageal, ovary, adenocarcinoma of unknown primary, lymphoma, gastric, duodenal, bladder, angiosarcoma, squamous cell carcinoma, thyroid, adrenal, and parotid. Patients underwent evaluation of baseline and follow-up liver function and tumor markers and computed tomographic or magnetic resonance imaging. Patients were observed for survival from first treatment. Median survival (in days) and corresponding 95% confidence intervals were computed by using the Kaplan-Meier method. The log-rank statistic was used for statistical significance testing of survival distributions between various subgroups of patients.

RESULTS

There were 66 men and 71 women. All patients were treated on an outpatient basis. Median age was 61 years. The mean number of treatments was 1.6. The median activity and dose infused were 1.83 GBq and 112.8 Gy, respectively. Clinical toxicities included fatigue (56%), vague abdominal pain (26%), and nausea (23%). At follow-up imaging, according to World Health Organization criteria, there was a 42.8% response rate (2.1% complete response, 40.7% partial response). There was a biologic tumor response (any decrease in tumor size) of 87%. Overall median survival was 300 days. One-year survival was 47.8%, and 2-year survival was 30.9%. Median survival was 457 days for patients with colorectal tumors, 776 days for those with neuroendocrine tumors, and 207 days for those with noncolorectal, nonneuroendocrine tumors.

CONCLUSION

(90)Y hepatic treatments are well tolerated with acceptable toxicities; tumor response and median survival are promising.

Technical aspects of radioembolization with 90Y microspheres

Embolotherapy with radioactive microspheres, radioembolization, is gaining clinical acceptance as a therapeutic option for patients with liver malignancies. Knowledge of the anatomic variants in the mesenteric system is critical to safely administer this therapy. The purpose of this review is to provide a thorough discussion and detailed presentation of the technical aspects of radioembolization specifically as it pertains to the implantation devices. Normal vascular anatomy, commonly encountered variants, and factors involved in changes to regional perfusion in the presence of liver tumors are discussed. In addition, the basic principles described in this manuscript apply to all liver-directed transarterial therapies, such as chemoembolization and/or drug-eluting microspheres.

Multimodality imaging following 90Y radioembolization: a comprehensive review and pictorial essay

Radioembolization with yttrium 90 (90Y) microspheres represents an emerging transarterial therapy for the treatment of liver malignancies that continues to generate interest in the medical community. The classic indication of treatment response is a reduction in tumor size; however, parenchymal changes (eg, necrosis, lack of enhancement, specific findings at positron emission tomography and functional magnetic resonance imaging) and other benign findings (pleural effusions, perivascular edema, contralateral hypertrophy, ring enhancement, perihepatic fluid, fibrosis) may occur following treatment, requiring proper image interpretation. With classic imaging findings and surrogates (time to progression, duration of response, disease-free interval), response rates range from 20% to 80% in patients treated for hepatocellular carcinoma or metastatic disease to the liver. Complications of 90Y radioembolization include cholecystitis, abscess, and bilomas and should be recognized early in the imaging follow-up of these patients. Radiologists who are involved in the posttreatment assessment of patients undergoing 90Y radioembolization should be familiar with the imaging findings and potential imaging pitfalls associated with this therapy.

Use of a combined MR imaging and interventional radiology suite for intraprocedural monitoring of uterine artery embolization

PURPOSE

The optimal embolic endpoint for uterine artery embolization (UAE) is unknown. It is difficult to quantify substasis endpoints with the use of conventional x-ray interventional radiology (IR) guidance. Although magnetic resonance (MR) imaging can detect perfusion changes, intraprocedural perfusion changes within targeted uterine leiomyomas and the remaining uterine wall remain unknown. A hybrid MR/IR unit was used to test the hypothesis that MR imaging can detect changes in uterine perfusion-dependent signal enhancement immediately after UAE.

MATERIALS AND METHODS

In this prospective study, UAE was performed in a hybrid MR/IR unit in women with symptomatic uterine leiomyomas. This MR/IR unit contains a wide-bore 1.5-T MR scanner connected by a sliding table to an adjacent x-ray digital subtraction angiography unit. Gadolinium-enhanced MR imaging was performed before and after UAE. Relative signal-to-noise ratio (SNR) was measured within each tumor and the adjacent uterine wall, and mean relative SNR changes were compared before and after UAE with the paired t test (alpha=0.05).

RESULTS

UAE was technically successful in all six women, in whom 10 tumors were assessed (seven intramural, two submucosal, one subserosal). Mean relative SNR of the tumors before UAE was 62.2+/-25.0 and was reduced to 41.1+/-17.7 after UAE (P<.01). Mean relative SNR of the adjacent uterine wall was 64.2+/-14.3 before UAE and decreased to 28.8+/-14.9 after UAE (P<.01).

CONCLUSIONS

Immediate reductions in perfusion-dependent enhancement in targeted uterine leiomyomas and the adjacent uterine wall can be detected during UAE with the use of a hybrid MR/IR unit. Further studies are now warranted to compare long-term clinical outcomes versus immediate changes in perfusion at the time of UAE.

Comparison of transcatheter intraarterial perfusion MR imaging and fluorescent microsphere perfusion measurements during transcatheter arterial embolization of rabbit liver tumors

PURPOSE

Transcatheter intraarterial perfusion (TRIP) magnetic resonance (MR) imaging is clinically used in the interventional MR imaging setting to verify distribution of injected embolic or chemoembolic material during liver-directed transcatheter therapies and to monitor reductions in perfusion. The accuracy of this technique remains unknown. In the present study, rabbit VX2 liver tumors were used to test the hypothesis that TRIP MR imaging accurately measures changes in tumor perfusion during transcatheter arterial embolization (TAE), with injection of fluorescent microspheres used as the gold-standard technique.

MATERIALS AND METHODS

Five New Zealand White rabbits were used for this study (two donor rabbits and three with VX2 liver tumors). In three rabbits with implanted VX2 liver tumors, catheters were superselectively placed under digital subtraction angiographic guidance into the left hepatic artery supplying the targeted tumor. Fluorescent microspheres were injected into each rabbit's left ventricle before and after TAE. TRIP MR images were obtained at baseline and after embolizations for all rabbits with intraarterial injections of 2.5% gadopentetate dimeglumine solution. Linear regression was used to compare relative reductions in tumor perfusion between TRIP MR imaging and fluorescent microspheres. Results were considered statistically significant at a P value less than .05.

RESULTS

There was good correlation between TRIP MR imaging and fluorescent microsphere measurements of reduction in tumor perfusion (r = 0.722, P < .012).

CONCLUSIONS

TRIP MR imaging provides accurate semiquantitative measurement of perfusion reduction during TAE in rabbit liver tumors.

A comparison of chemoembolization endpoints using angiographic versus transcatheter intraarterial perfusion/MR imaging monitoring

PURPOSE

Transcatheter arterial chemoembolization (TACE) is an established treatment for unresectable liver cancer. This study was conducted to test the hypothesis that angiographic endpoints during TACE are measurable and reproducible by comparing subjective angiographic versus objective magnetic resonance (MR) endpoints of TACE.

MATERIALS AND METHODS

The study included 12 consecutive patients who presented for TACE for surgically unresectable HCC or progressive hepatic metastases despite chemotherapy. All procedures were performed with a dedicated imaging system. Angiographic series before and after TACE were reviewed independently by three board-certified interventional radiologists. A subjective angiographic chemoembolization endpoint (SACE) classification scheme, modified from an established angiographic grading system in the cardiology literature, was designed to assist in reproducibly classifying angiographic endpoints. Reproducibility in SACE classification level was compared among operators, and MR imaging perfusion reduction was compared with SACE levels for each observer.

RESULTS

Twelve patients successfully underwent 15 separate TACE sessions. SACE levels ranged from I through IV. There was moderate agreement in SACE classification (kappa = 0.46 +/- 0.12). There was no correlation between SACE level and MR perfusion reduction (r = 0.16 for one operator and 0.02 for the other two).

CONCLUSIONS

Angiographic endpoints during TACE vary widely, have moderate reproducibility among operators, and do not correlate with functional MR imaging perfusion endpoints. Future research should aim to determine ideal angiographic and functional MR imaging endpoints for TACE according to outcome measures such as imaging response, pathologic response, and survival.

Effect of C-arm angiographic CT on transcatheter arterial chemoembolization of liver tumors

Rotational C-arm angiographic computed tomography (CT) with a flat-panel radiography unit permits three-dimensional (3D) reconstruction of soft tissues and blood vessels. The usefulness of this C-arm technique during transcatheter arterial chemoembolization (TACE) is unknown. The authors analyzed the role of the C-arm technique in 18 patients with unresectable liver tumors during TACE. The technique altered the catheter position anticipated by attending interventional radiologists in seven of the 18 patients (39%; 95% confidence interval [CI]: 20%, 61%) and improved the diagnostic confidence in the selected catheter position in 14 of the 18 patients (78%; 95% CI: 55%, 91%). The technique provides CT-like images that are useful to interventional radiologists during TACE.

Safety and efficacy of 90Y radiotherapy for hepatocellular carcinoma with and without portal vein thrombosis

This study was undertaken to present data from a phase 2 study in which patients with unresectable hepatocellular carcinoma (HCC) with and without portal vein thrombosis underwent radioembolization with Yttrium ((90)Y) microspheres. Patients treated were stratified by Okuda, Child-Pugh, baseline bilirubin, tumor burden, Eastern Cooperative Oncology Group (ECOG), presence of cirrhosis and portal vein thrombosis (PVT) (none, branch, and main). Clinical and biochemical data were obtained at baseline and at 4-week intervals following treatment for up to 6 months. Tumor response was obtained using computed tomography (CT). Patients were followed for survival. One hundred eight patients were treated during the study period. Thirty-seven (34%) patients had PVT, 12 (32%) of which involved the main PV. The cumulative dose for those with and without PVT was 139.7 Gy and 131.9 Gy, respectively. The partial response rate using world Health Organization (WHO) criteria was 42.2%. Using European Association for the Study of the Liver (EASL), the response rate was 70%. Kaplan-Meier survival varied depending on location of PVT and presence of cirrhosis. The adverse event (AE) rates were highest in patients with main PVT and cirrhosis. There were no cases of radiation pneumonitis.

CONCLUSION

The use of minimally embolic (90)Y glass microspheres to treat patients with HCC complicated by branch/lobar PVT may be clinically indicated and appears to have a favorable toxicity profile. Further investigation is warranted in patients with main PVT.

90Y radioembolization of metastatic breast cancer to the liver: toxicity, imaging response, survival

PURPOSE

To present data from patients with breast cancer liver metastases who underwent radioembolization with yttrium (90Y) microspheres.

MATERIALS AND METHODS

Using standard 90Y lobar treatment protocol, 27 female patients with progressing liver metastases on standard of care polychemotherapy were treated under an open-label phase 2 protocol. After treatment, we assessed (a) tumor response using computed tomography and/or positron emission tomography, (b) biochemical toxicity, and (c) survival.

RESULTS

The mean age of the patients was 52. Seventeen (63%) patients received 20 left lobe treatments (median radiation dose, 123 Gy; mean, 119 Gy), and 20 (74%) patients received 22 right lobe treatments (median radiation dose, 121 Gy; mean, 109 Gy) to the treatment site. No significant dose-difference was noted between the two lobes (P=.69). Tumor response on 90-day follow-up computed tomography showed (a) complete and partial response in nine (39.1%) patients, (b) stable disease in 12 (52.1%) patients, and (c) progressive disease in 2 (8.8%) patients. Positive tumor response on positron emission tomography was noted in 17 (63%) patients. Three of 27 (11%) patients (Eastern Cooperation Oncology Group 1, 2, or 3) showed bilirubin toxicity of grade 3, all of which were attributed to disease progression. Median survival for Eastern Cooperation Oncology Group 0 versus 1, 2, or 3 patients was 6.8 months and 2.6 months, respectively (P=.24) and for patients with tumor burden<25% versus >25% was 9.4 and 2.0 months, respectively (P=.46).

CONCLUSIONS

Radioembolization with 90Y brachytherapy device may be a viable therapeutic option for the treatment of breast cancer liver metastases in patients who have progressed or failed on standard of care polychemotherapy.