SPECT/CT with ^99mTc-MAA in Radioembolization with ⁹⁰Y Microspheres in Patients with Hepatocellular Cancer

Abstract

Radioembolization with 90 Y microspheres is a novel treatment for hepatic tumors. Generally, hepatic arteriography and 99m Tc-macroaggregated albumin (MAA) scanning are performed before selective internal radiation therapy to detect extrahepatic shunting to the lung or the gastrointestinal tract. Whereas previous studies have used only planar or SPECT scans, the present study used 99m Tc-MAA SPECT/CT scintigraphy (SPECT with integrated low-dose CT) to evaluate whether SPECT/CT and additional diagnostic contrast-enhanced CT before radioembolization with 90 Y microspheres are superior to SPECT or planar imaging alone for detection of gastrointestinal shunting. Methods: In a prospective study, we enrolled 58 patients (mean age, 66 y; SD, 12 y; 10 women and 48 men) with hepatocellular carcinoma who underwent hepatic arteriography and scintigraphy with 99m Tc-MAA using planar imaging, SPECT, and SPECT with integrated low-dose CT of the upper abdomen (acquired with a hybrid SPECT/CT camera). The ability of the different imaging modalities to detect extrahepatic MAA shunting was compared. Patient follow-up of a mean of 180 d served as the standard of reference. Results: Gastrointestinal shunting was revealed by planar imaging in 4, by SPECT in 9, and by SPECT/CT in 16 of the 68 examinations. For planar imaging, the sensitivity for detection of gastrointestinal shunting was 25%, the specificity 87%, and the accuracy 72%. For SPECT without CT, the sensitivity was 56%, the specificity 87%, and the accuracy 79%. SPECT with CT fusion had a sensitivity of 100%, a specificity of 94%, and an accuracy of 96%. In 3 patients, MAA deposits in the portal vein could accurately be attributed to tumor thrombus only with additional information from contrast-enhanced CT. The follow-up did not show any gastrointestinal complications. Conclusion: SPECT with integrated low-dose CT using 99m Tc-MAA is beneficial in radioembolization with 90 Y microspheres because it increases the sensitivity and specificity of 99m Tc-MAA SPECT when detecting extrahepatic arterial shunting. The overall low risk of gastrointestinal complications in radioembolization may therefore be further reduced by SPECT/CT. Radi oembolization with 90 Y microspheres via hepatic arterial administration is emerging as a promising treatment for patients with primary and metastatic liver cancer (1-4). 90 Y microspheres are currently approved in the United States for the treatment of hepatocellular carcinoma (TheraSphere; MDS Nordion) and colorectal cancer (SIR-Spheres; Sirtex Medical). 90 Y microspheres are injected into the arterial supply of the liver, where they preferentially flow into hypervascularized tumor areas, resulting in a significantly higher irradiation of tumor tissue than of normal liver parenchyma (5). With improvements in technology permitting smaller vessels to be catheterized and refinements in imaging techniques, the safety and efficacy of 90 Y microsphere delivery has improved significantly (6-10).Liver-directed therapy with 90 Y provides several advantag...

A review of 3D image-based dosimetry, technical considerations and emerging perspectives in 90Y microsphere therapy

“…There is broad agreement on SPECT-CT being more clinically useful in terms of extrahepatic uptake and more accurate in terms of activity quantification than either SPECT or planar imaging [18][19][20] with a recent study of 58 patient scans showing rates of detection of extrahepatic MAA was 72%, 79% and 96% for planar, SPECT and SPECT-CT, respectively [21]. Other studies have identified extrahepatic uptake on SPECT-CT not discernable on planar or SPECT only, leading to treatment adjustments such as additional surgical embolization [18,22].…”

Multiagent imaging of liver tumors with reference to intra-arterial radioembolization

“…The sensitivities were 100, 41 and 32 % and the specificities 98, 98 and 93 % for SPECT/CT, SPECT and planar imaging, respectively. In a prospective study Hamami et al [27], evaluating 68 99m Tc-MAA procedures performed in 58 patients with HCC, demonstrated a superior performance of SPECT/CT over SPECT and planar imaging (sensitivity 100 %, specificity 94 % for SPECT/CT versus 56 and 87 %, respectively, for SPECT). Similarly, in a report published by Lenoir et al [28] the superiority of SPECT/CT over planar imaging was demonstrated analyzing 136 hepatic perfusion scintigraphies.…”

Intraarterial Hepatic SPECT/CT Imaging Using 99mTc-Macroaggregated Albumin in Preparation for Radioembolization

“…Transaxial and sagittal reconstructed SPECT/CT image shows 99m Tc-MAA uptake within anterior abdominal wall due to flow from falciform artery, which originated from middle hepatic artery. (10,(12)(13)(14)(15)(16). This study reports our experience in treatment planning for 174 patients.…”

“…1-3). A detailed discussion of considerations of normal hepatic perfusion and hepaticoenteric arterial anatomy in the context of radioembolization has been published elsewhere (10,(12)(13)(14)(15)(16). In a recent publication by Ilhan et al, SPECT/CT images were reviewed for tumor uptake distribution and graded on the basis of the concentration of 99m Tc-MAA and distribution within the tumor (17).…”

“…Technical details for radioembolization have been discussed in detail elsewhere (10,11). Ninety-one patients were being treated for metastatic disease of the liver (colorectal cancer [40], neuroendocrine disease [20], cholangiocarcinoma [15], and miscellaneous origin [16]). Eighty-three patients were being treated for primary hepatocellular carcinoma (HCC).…”