Manli Jiang

The optimized evaluation of diabetic foot infection by dual isotope SPECT/CT imaging protocol.

Sequential Tc-99m hydroxymethylene-diphosphonate (HDP) 3-phase bone (BS) and In-111 leukocyte scanning (WBCS) have been frequently used to evaluate the diabetic foot, as nonosteomyelitis BS uptake is repeatedly observed and osteomyelitis (OM) in WBCS is often uncertain without BS correlation. Additionally, both modalities are limited in lesion localization because of low resolution and lack of anatomic details. We investigated a method that combined BS/WBCS, and if needed, WBCS/bone marrow scanning (BMS) using SPECT/CT to accurately diagnose/localize infection in a practical protocol. Blood flow/pool images were obtained followed by WBC reinjection and next day dual isotope (DI) BS/WBCS planar and SPECT/CT. BMS/WBCS SPECT/CT (step 2 DI) was obtained on the following day when images were suspicious for mid/hindfoot OM. Diagnosis accuracy and confidence were judged for the various imaging combinations. Diagnosis was classified as OM, soft tissue infection (STI), both OM/STI, and other/no bony pathology by microbiology/pathology or follow-up. Distinction between various diagnostic categories and overall OM diagnostic accuracy in 213 patients were higher for DI than WBCS or BS alone, and for DI SPECT/CT than DI planar or SPECT only. Diagnostic confidence/lesion site was significantly higher for DI SPECT/CT than other comparative imaging methods. In a group of 97 patients with confirmed microbiologic/pathologic diagnosis, similar results were attained. Step 2 DI SPECT/CT performed in 67 patients further improved diagnostic accuracy/confidence. DI SPECT/CT is a highly accurate modality that considerably improves detection and discrimination of STI and OM while providing precise anatomic localization in the diabetic foot. This combined imaging technique promises to beneficially impact diabetic patient care.

Characterization of extrahepatic distribution of Tc-99m macroaggregated albumin in hepatic perfusion imaging studies prior to yttrium-90 microsphere therapy.

Tc-99m macroaggregated albumin (MAA) hepatic perfusion study and hepatic angiography are routinely performed prior to yttrium-90 (Y-90) microsphere therapy for patients with hepatocellular carcinoma (HCC) or metastatic cancers to the liver. The purpose of this study was to examine the incidence of altered Tc-99m MAA distribution in these patients and to identify factors that are associated with these changes. A total of 176 Tc-99m MAA hepatic perfusion studies in 159 patients performed in preparation for Y-90 microsphere therapy were retrospectively reviewed. Abnormal findings were identified and correlated with diagnosis, infusion site, tumor volume, and tumor uptake by using bivariate statistical analysis. Abnormal Tc-99m MAA distribution on the hepatic perfusion imaging studies include excessive hepatopulmonary shunting with an elevated shunting fraction (>10%; n=23, 13%) and abnormal intra-abdominal visceral deposition in the GI tract, pancreas, spleen, and umbilical vein (n=19; 11%). Patients with a diagnosis of HCC showed higher incidence of abnormal hepatopulmonary shunting compared with other types of tumors (p<0.05). The incidence of abnormal intra-abdominal visceral deposition is higher with infusion into the left hepatic artery or proper hepatic artery/common hepatic artery compared with infusion into right hepatic artery (p<0.001). In 9 of 12 cases with abnormal deposition in the stomach, duodenum, or pancreas, the cause was identified upon reviewing angiography retrospectively and was subsequently corrected. In conclusion, the hepatic perfusion imaging study is an important imaging modality in preparation and guidance of Y-90 microsphere treatment.