N. Kothary

Renal angiomyolipoma: Long-term results after arterial embolization

PURPOSE Selective arterial embolization of renal angiomyolipomas (AMLs) was performed to prevent hemorrhage in patients with AMLs larger than 4 cm. This study was conducted to evaluate the long-term efficacy of AML embolization. MATERIALS AND METHODS Nineteen patients underwent embolization for 30 renal AMLs between July 1991 and June 2002. Of these, 10 patients had tuberous sclerosis (TS) with multiple AMLs and nine patients had a solitary sporadic AML. Embolization was performed with use of ethanol mixed with iodized oil (Ethiodol) in 29 tumors; coils were used in addition to the ethanol/Ethiodol mixture in one case. All tumors were completely embolized according to angiographic criteria including vascular stasis and absence of arterial feeders. The efficacy of embolization was determined over a mean follow-up period of 51.5 months (range, 6-132 months). Recurrence was defined as an increase in tumor size of greater than 2 cm on follow-up imaging and/or recurrent symptoms that required repeat embolization. An institutional review board exemption was obtained to perform this retrospective study. RESULTS Embolization of the renal AMLs was technically successful in all 19 patients and for all 30 lesions. AML recurrence was noted in 31.6% of patients (n = 19) and for 30% of lesions overall (n = 9). Six of 10 patients in the TS group had AML recurrences. No recurrences occurred in the patients with sporadic AML. In the TS group of 10 patients, there was a total of 21 AMLs and the overall tumor recurrence rate was 42.9% (nine of 21). Six lesions in four patients had to be reembolized because of recurrent symptoms, including one hemorrhage, and three lesions in two patients required repeat embolization because of a greater than 2 cm increase in size. The median time interval from embolization to recurrence was 78.7 months (range, 13-132 months). Statistical testing with use of the Fisher exact test demonstrated that patients with TS were significantly more likely to develop recurrence than those without TS (P = .01). CONCLUSIONS Transarterial embolization is effective in preventing hemorrhage in patients with renal AMLs. However, long-term follow-up revealed a high AML recurrence rate in patients with TS. Lifelong surveillance for recurrence after AML embolization is essential in patients with TS.

Safety and Efficacy of Percutaneous Fiducial Marker Implantation for Image-guided Radiation Therapy

PURPOSE To evaluate the safety and technical success rate of percutaneous fiducial marker implantation in preparation for image-guided radiation therapy. MATERIALS AND METHODS From January 2003 to January 2008, we retrospectively reviewed 139 percutaneous fiducial marker implantations in 132 patients. Of the 139 implantations, 44 were in the lung, 61 were in the pancreas, and 34 were in the liver. Procedure-related major and minor complications were documented. Technical success was defined as implantation enabling adequate treatment planning and computed tomographic simulation. RESULTS The major and minor complication rates were 5% and 17.3%, respectively. Pneumothorax after lung implantation was the most common complication. Pneumothoraces were seen in 20 of the 44 lung implantations (45%); a chest tube was required in only seven of the 44 lung transplantations (16%). Of the 139 implantations, 133 were successful; in six implantations (4.3%) the fiducial markers migrated and required additional procedures or alternate methods of implantation. CONCLUSIONS Percutaneous implantation of fiducial marker is a safe and effective procedure with risks that are similar to those of conventional percutaneous organ biopsy.

Computed Tomography-Guided Percutaneous Needle Biopsy of Pulmonary Nodules: Impact of Nodule Size on Diagnostic Accuracy

PURPOSE This study was undertaken to compare the diagnostic accuracy and complication rate of computed tomography (CT)-guided percutaneous lung biopsies of lung nodules<or=1.5 cm versus >1.5 cm in diameter. PATIENTS AND METHODS A total of 139 patients (age range, 18-89 years; mean, 62.5 years) underwent CT-guided percutaneous fine-needle aspiration biopsy or 20-gauge core biopsy using an automated biopsy gun. In 37 patients, the lung nodule measured <or=1.5 cm (mean, 1.1 cm), and in 102 patients, the lung nodule was >1.5 cm (mean, 2.8 cm). Diagnostic accuracy was determined by cytopathology results. Major and minor complications were documented. RESULTS Overall diagnostic accuracy, pneumothorax rate, and thoracostomy tube insertion rates were 67.6%, 34.5%, and 5%, respectively. Of the 98 patients with malignancy, 77 patients (78.6%) had a definite diagnostic biopsy. Overall, nodules>1.5 cm were statistically more likely to result in a diagnostic specimen (73.5%) than nodules<or=1.5 cm (51.4%; P=.012). Similarly, diagnostic accuracy for malignancy was higher in nodules>1.5 cm than in those<or=1.5 cm (81.3% vs. 69.6%); however, this was not statistically significant. There was no correlation between nodule size and the incidence of complications. CONCLUSION Overall, diagnostic accuracy of CT-guided percutaneous lung biopsy of lung nodules<or=1.5 cm is slightly lower than that of nodules>1.5 cm. However, the diagnostic accuracy for malignancy is high in both groups, with a low risk of complications.

Catheter-Directed Embolectomy, Fragmentation, and Thrombolysis for the Treatment of Massive Pulmonary Embolism After Failure of Systemic Thrombolysis

PURPOSES The standard medical management for patients in extremis from massive pulmonary embolism (PE) is systemic thrombolysis, but the utility of this treatment relative to catheter-directed intervention (CDI) is unknown. We evaluated the effectiveness of CDI as part of a treatment algorithm for life-threatening PE. METHODS A retrospective review was performed on 70 consecutive patients with suspected acute PE over a 10-year period (from 1997 to 2006) who had been referred for pulmonary angiography and/or intervention. The criteria for study inclusion were patients who received CDI due to angiographically confirmed massive PE and hemodynamic shock (shock index, > or = 0.9). CDI involved suction embolectomy and fragmentation with or without catheter thrombolysis. RESULTS Twelve patients were treated with CDI. There were seven men and five women (mean age, 56 years; age range, 21 to 80 years). Seven patients (58%) were referred for CDI after failing systemic infusion with 100 mg of tissue plasminogen activator, and five patients (42%) had contraindications to systemic thrombolysis. Catheter-directed fragmentation and embolectomy were performed in all patients (100%). Additionally, catheter-guided thrombolysis was performed in eight patients (67%). Technical success was achieved in 12 of 12 cases (100%). There were no major procedural complications (0%). Significant hemodynamic improvement (shock index, < 0.9) was observed in 10 of 12 cases (83%). The remaining two patients (17%) died secondary to cardiac arrest within 24 h. Ten of 12 patients (83%) survived and remained stable until hospital discharge (mean duration, 20 days; range, 3 to 51 days). CONCLUSION In the setting of hemodynamic shock from massive PE, CDI is potentially a life-saving treatment for patients who have not responded to or cannot tolerate systemic thrombolysis.

Incorporating Cone-beam CT into the Treatment Planning for Yttrium-90 Radioembolization

PURPOSE To prepare for yttrium-90 ((90)Y) microsphere radioembolization therapy, digital subtraction angiography (DSA) and technetium- 99m-labeled macroaggregated albumin ((99m)Tc MAA) scintigraphy are used for treatment planning and detection of potential nontarget embolization. The present study was performed to determine if cone-beam computed tomography (CBCT) affects treatment planning as an adjunct to these conventional imaging modalities. MATERIALS AND METHODS From March 2007 to August 2008, 42 consecutive patients (21 men, 21 women; mean age, 59 years; range, 21-75 y) who underwent radioembolization were evaluated by CBCT in addition to DSA and (99m)Tc MAA scintigraphy during treatment planning, and their records were retrospectively reviewed. The contrast-enhanced territories shown by CBCT with selective intraarterial contrast agent administration were used to predict intrahepatic and possible extrahepatic distribution of microspheres. RESULTS In 22 of 42 cases (52%), extrahepatic enhancement or incomplete tumor perfusion seen on CBCT affected the treatment plan. In 14 patients (33%), the findings were evident exclusively on CBCT and not detected by DSA. When comparing CBCT versus (99m)Tc MAA scintigraphy, CBCT showed eight cases of extrahepatic enhancement (19%) that were not evident on (99m)Tc MAA imaging. CBCT findings directed the additional embolization of vessels or repositioning of the catheter for better contrast agent and microsphere distribution. One case of gastric ulcer from nontarget embolization caused by reader error was observed. CONCLUSIONS CBCT can provide additional information about tumor and tissue perfusion not currently detectable by DSA or (99m)Tc MAA imaging, which should optimize (90)Y microsphere delivery and reduce nontarget embolization.

Utility of C-arm CT in Patients with Hepatocellular Carcinoma undergoing Transhepatic Arterial Chemoembolization

PURPOSE To evaluate the utility of C-arm computed tomography (CT) on treatment algorithms in patients undergoing transhepatic arterial chemoembolization for hepatocellular carcinoma (HCC). MATERIALS AND METHODS From March 2008 to July 2008, 84 consecutive patients with HCC underwent 100 consecutive transhepatic arterial chemoembolizations with iodized oil. Unenhanced and iodinated contrast medium-enhanced C-arm CT with planar and three-dimensional imaging were performed in addition to conventional digital subtraction angiography (DSA) in all patients. The effect on diagnosis and treatment was determined by testing the hypotheses that C-arm CT, in comparison to DSA, provides (a) improved lesion detection, (b) expedient identification and mapping of arterial supply to a tumor, (c) improved characterization of a lesion to allow confident differentiation of HCC from pseudolesions such as arterioportal shunts, and (d) an improved evaluation of treatment completeness. The effect of C-arm CT was analyzed on the basis of information provided with C-arm CT that was not provided or readily apparent at DSA. RESULTS C-arm CT was technically successful in 93 of the 100 procedures (93%). C-arm CT provided information not apparent or discernible at DSA in 30 of the 84 patients (36%) and resulted in a change in diagnosis, treatment planning, or treatment delivery in 24 (28%). The additional information included, amongst others, visualization of additional or angiographically occult tumors in 13 of the 84 patients (15%) and identification of incomplete treatment in six (7.1%). CONCLUSIONS C-arm CT is a useful collaborative tool in patients undergoing transhepatic arterial chemoembolization and can affect patient care in more than one-fourth of patients.

Radiologic Monitoring of Hepatocellular Carcinoma Tumor Viability after Transhepatic Arterial Chemoembolization: Estimating the Accuracy of Contrast-enhanced Cross-sectional Imaging with Histopathologic Correlation

PURPOSE Cross-sectional diagnostic imaging studies such as contrast-enhanced quadruple-phase helical computed tomography (CT) and contrast-enhanced magnetic resonance (MR) imaging are routinely performed to evaluate tumor response to transhepatic arterial chemoembolization. However, the true correlation between imaging characteristics and histopathologic tumor viability is not known. The aim of the present retrospective study was to determine the sensitivity and specificity of contrast-enhanced CT and contrast-enhanced MR imaging with use of histopathologic analysis. MATERIALS AND METHODS Between February 2002 and October 2005, a total of 31 patients (age, 51-74 years; mean, 60 y) who had undergone chemoembolization underwent follow-up diagnostic cross-sectional imaging before transplantation. The mean time interval between the imaging study and transplantation was 32 days (range, 1-117 d). Imaging studies were assessed for residual or recurrent tumor and were then correlated to the findings of histopathologic analysis performed on the surgical specimens at the time of transplantation. RESULTS The overall sensitivity and specificity rates of cross-sectional imaging studies were 35% and 64%, respectively. The overall accuracy rate of CT was 43%, with 36% sensitivity and 57% specificity. The overall accuracy rate of MR imaging was 55%, with 43% sensitivity and 75% specificity. Gross macroscopic disease was missed in one patient (9%) who underwent MR imaging and four patients (19%) who underwent CT. CONCLUSIONS Contrast-enhanced CT and MR imaging after chemoembolization are associated with high error rates. Between the two modalities, MR has higher sensitivity and specificity and may be a preferable imaging tool for patients who have undergone chemoembolization.

Imaging Guidance with C-arm CT: Prospective Evaluation of Its Impact on Patient Radiation Exposure during Transhepatic Arterial Chemoembolization

PURPOSE To prospectively evaluate the impact of C-arm CT on radiation exposure to hepatocellular carcinoma (HCC) patients treated by chemoembolization. MATERIALS AND METHODS Patients with HCC (N = 87) underwent digital subtraction angiography (DSA; control group) or combined C-arm CT/DSA (test group) for chemoembolization. Dose-area product (DAP) and cumulative dose (CD) were measured for guidance and treatment verification. Contrast agent volume and C-arm CT utility were also measured. RESULTS The marginal DAP increase in the test group was offset by a substantial (50%) decrease in CD from DSA. Use of C-arm CT allowed reduction of DAP and CD from DSA imaging (P = .007 and P = .017). Experienced operators were more efficient in substituting C-arm CT for DSA, resulting in a negligible increase (7.5%) in total DAP for guidance, compared with an increase of 34% for all operators (P = .03). For treatment verification, DAP from C-arm CT exceeded that from DSA, approaching that of conventional CT. The test group used less contrast medium (P = .001), and C-arm CT provided critical or supplemental information in 20% and 17% of patients, respectively. CONCLUSIONS Routine use of C-arm CT can increase stochastic risk (DAP) but decrease deterministic risk (CD) from DSA. However, the increase in DAP is operator-dependent, thus, with experience, it can be reduced to under 10%. C-arm CT provides information not provided by DSA in 33% of patients, while decreasing the use of iodinated contrast medium. As with all radiation-emitting modalities, C-arm CT should be used judiciously.

Development of new hepaticoenteric collateral pathways after hepatic arterial skeletonization in preparation for yttrium-90 radioembolization.

PURPOSE Development of new hepaticoenteric anastomotic vessels may occur after endovascular skeletonization of the hepatic artery. Left untreated, they can serve as pathways for nontarget radioembolization. The authors reviewed the incidence, anatomy, management, and significance of collateral vessel formation in patients undergoing radioembolization. MATERIALS AND METHODS One hundred thirty-eight treatments performed on 122 patients were reviewed. Each patient underwent a preparatory digital subtraction angiogram (DSA) and embolization of all hepaticoenteric vessels in preparation for yttrium-90 ((90)Y) administration. Successful skeletonization was verified by C-arm computed tomography (CACT) and technetium-99m macroaggregated albumin ((99m)TcMAA) scintigraphy. During the subsequent treatment session, DSA and CACT were repeated before administration of (90)Y, and the detection of extrahepatic perfusion prompted additional embolization. RESULTS Forty-two patients (34.4%) undergoing 43 treatments (31.2%) required adjunctive embolization of hepaticoenteric vessels immediately before (90)Y administration. Previous scintigraphy findings showed extrahepatic perfusion in only three cases (7.1%). Vessels were identified by DSA in 54.1%, by CACT in 4.9%, or required both in 41.0%. The time interval between angiograms did not correlate with risk of requiring reembolization (P = .297). A total of 19.7% of vessels were new collateral vessels not visible during the initial angiography. Despite reembolization, three patients (7.1%) had gastric or duodenal ulceration, compared with 1.3% who never had visible collateral vessels, all of whom underwent whole-liver treatment with resin microspheres (P = .038). CONCLUSIONS Development of collateral hepaticoenteric anastomoses occurs after endovascular skeletonization of the hepatic artery. Identified vessels may be managed by adjunctive embolization, but patients appear to remain at increased risk for gastrointestinal complications.

Percutaneous Implantation of Fiducial Markers for Imaging-Guided Radiation Therapy

OBJECTIVE The use of imaging-guided radiation therapy (IGRT) to treat thoracic and abdominal tumors is increasing. In this article, we review the process of IGRT and describe techniques to implant fiducial markers in the optimal geometry. CONCLUSION Implantation of fiducial markers can be challenging. A better understanding of the physics of IGRT can help optimize fiducial marker placement for precise tumor targeting.