68Ga-DOTATATE Uptake in a Soft Tissue Metastasis From Clear Cell Renal Cell Cancer.

A 64-year-old man with a history of metastatic clear cell renal cell cancer was referred for progress Ga-DOTATATE PET/CT imaging. Ga-DOTATATE PET/CT imaging demonstrated increased DOTATATE uptake (SUVmax 13.8) in the left thigh localized to a soft tissue lesion. Cytopathology of the resected lesion was in keeping with a clear cell renal cell cancer metastasis. This case illustrates that Ga-DOTATATE accumulation in a soft tissue lesion can be due to a clear cell renal cell cancer metastasis.

Incidental Detection of Hepatocellular Carcinoma on 68Ga-Labeled Prostate-Specific Membrane Antigen PET/CT.

A 66-year-old man with history of prostate carcinoma underwent Ga-labeled prostate-specific membrane antigen PET/CT for surveillance of rising prostate-specific antigen. Intense tracer uptake was noted in segments 2, 7, and 8 of the liver. The lesions were not FDG avid on F-FDG PET/CT. Further characterization with magnetic resonance cholangiopancreatography with Gd-EOB (Primovist) contrast revealed ill-defined arterially enhancing lesions with central washout in the venous phase. CT-guided core biopsy was performed, and histopathology confirmed well-differentiated hepatocellular carcinoma.

Platelet activation in acute pulmonary embolism.

BACKGROUND: Platelet activation is implicated in thrombotic disorders, but has not been described in acute clinical pulmonary embolism (PE). OBJECTIVES: To investigate the natural history of platelet activation in PE and associated markers of inflammation, thrombosis and cardiac dysfunction. METHODS: Thirty-five consecutive patients (age 62 +/-17 years) with acute PE were prospectively enrolled and followed for 6 months. Platelet activation was assessed by flow cytometry [measuring expression of platelet P-selectin, conformational activation of glycoprotein IIb/IIIa complex (PAC-1) and formation of platelet-leukocyte complexes] and by plasma soluble P-selectin. Platelet activation, right ventricular (RV) function (assessed as RV ejection area by transthoracic echocardiography), D-dimer and high-sensitivity C-reactive protein (hs-CRP) were measured at presentation and repeated over 6 months follow-up. RESULTS: Soluble P-selectin (56 +/-19 ng mL(-1), anovaP < 0.0001) and PAC-1 (1.5 +/- 1.8%, anovaP = 0.005) were mildly but significantly increased in patients with acute PE relative to healthy young men (soluble P-selectin 33 +/- 13 ng mL(-1), P < 0.001; PAC-1 binding 0.5 +/- 0.6%, P < 0.01) and age-matched controls (soluble P-selectin 31 +/- 9 ng mL(-1), P < 0.001; PAC-1 binding 0.4 +/-0.4%, P < 0.05). Platelet P-selectin expression and platelet-leukocyte complexes were not increased during acute PE. Echocardiographic RV ejection area correlated inversely with soluble P-selectin (r = -0.47, P = 0.007) and positively with platelet P-selectin (r = 0.49, P = 0.0007), suggesting P-selectin is shed from activated platelets in proportion to the severity of RV dysfunction. Elevated soluble P-selectin, D-dimer and hs-CRP demonstrated a time-dependent return to normal during 6 months follow-up. CONCLUSION: Platelet activation is evident after acute PE. Platelet activation correlates with the severity of RV dysfunction, and can persist for several months after acute PE.

Tl-201 and Ga-67 scintigraphy in non-Hodgkin's lymphoma.

Ga-67 scintigraphy is routinely used to stage and monitor non-Hodgkin's lymphoma (NHL). It is highly sensitive in high-grade NHL but less so in intermediate- and low-grade NHL. Several studies have reported the use of Tl-201 in the low and intermediate grades of NHL and found it superior in low-grade NHL. In this study, the authors evaluated the utility of combined Ga-67 and Tl-201 scintigraphy in low, intermediate, and unusual types of NHL. Combined Tl-201 and Ga-67 scintigraphy were done in 33 patients (18 women, 15 men; age range, 21-91 years; mean age, 56 years). Tl-201 and Ga-67 had similar overall patient sensitivity in the 33 patients studied. However, the use of both agents increased the overall patient sensitivity from 67% (for Ga-67 only) to 82% and improved the overall site detection from 59 positive sites with Ga-67 to 81 abnormal sites with both Tl-201 and Ga-67. The combined use of Tl-201 and Ga-67 scintigraphy in low- and intermediate-grade NHL resulted in increased disease and site detection and is beneficial for clinical follow-up.

Gated TI-201 myocardial perfusion SPECT: application of energy window optimization.

PURPOSE: TI-201 scintigraphy is plagued with poor image quality because of the low-energy photons of TI-201 decay. Traditionally, a narrow 20% window centered on 71-72 keV has been used to improve sensitivity. Recent studies indicate that better imaging may be possible by optimizing the energy window to 34% centered on 77 keV. In this study, energy window optimization (EWO) was applied to gated TI-201 myocardial perfusion SPECT, and myocardial functional parameters were compared for gated TI-201 SPECT and gated Tc-99m sestamibi (Tc-99m MIBI) SPECT. METHODS: Count statistics for standard and optimal TI-201 myocardial scintigraphy were noted in 25 patients by assessing the total counts in a mid-ventricular slice of a rest-gated TI-201 myocardial SPECT study. The feasibility of performing functional studies with the application of EWO to TI-201 was assessed using the count statistics of a mid-ventricular slice of an optimized gated TI-201 SPECT study and a gated Tc-99m MIBI SPECT study. The functional parameters (ejection fraction, wall motion, and thickening) of TI-201 with EWO and Tc-99m MIBI were compared in 60 patients who underwent rest-gated TI-201 SPECT followed by poststress gated Tc-99m MIBI SPECT. The left ventricular ejection fraction was calculated using commercially available software, whereas wall thickness and motion were assessed by the consensus of two readers. RESULTS: The application of EWO increased available counts by more than 25%. It also resulted in sufficient counts being available to perform gated TI-201 SPECT without increasing acquisition times or the dose of TI-201. The average ejection fraction was 60.4% for gated TI-201 SPECT and 59.6% for gated Tc-99m MIBI SPECT (not significantly different). Overall, the image quality was rated excellent in 12% for TI-201 and Tc-99m MIBI and good in 50% and 62%, respectively, and poor in 38% and 26%, respectively. CONCLUSION: The application of EWO to TI-201 SPECT allows myocardial functional parameters to be assessed without having to increase the acquisition times or the administered dose of TI-201.

Tl-201 myocardial perfusion SPECT: role of nitrate-augmented redistribution.

PURPOSE: TI-201 myocardial perfusion SPECT is commonly used to assess myocardial perfusion and viability. Nitrate-augmented redistribution with repeated injection facilitates the detection of reversible segments compared with standard redistribution. In this study, we investigated the potential of nitrate augmentation to improve myocardial perfusion and viability assessment without repeated injection and we also compared nitrate-augmented redistribution with delayed redistribution. METHODS: Eighteen patients underwent a stress-redistribution TI-201 SPECT study. Immediately after redistribution SPECT, each patient was administered 0.6 mg glyceryl trinitrate and nitrate-augmented redistribution SPECT acquired 30 minutes later. Each patient then returned the next day and was injected with a booster dose of TI-201 30 minutes before the delayed redistribution SPECT acquisition. For each SPECT study, the myocardium was divided into 11 segments, and perfusion to each segment was scored on a four-point scale by consensus. An overall cardiac perfusion score was derived by summing the perfusion score for each segment. RESULTS: Reduced stress perfusion was identified in 150 segments: 23 (15.3%) had improved perfusion after redistribution; 60 (40%) segments had improved perfusion after nitrate-augmented redistribution; 52 (34.7%) segments with reduced stress perfusion had improved perfusion after delayed redistribution. The cardiac perfusion score after stress was 15.9+/-5.5 (means+/-SD). The score increased to 17.4+/-5.4 after redistribution. The perfusion score improved to 19.7+/-5.8 (P < 0.05 versus redistribution) after nitrate augmentation. The cardiac perfusion score, 19.2+/-6.4, did not improve further after delayed redistribution. CONCLUSIONS: TI-201 SPECT with nitrate-augmented redistribution is as good or better than delayed redistribution with repeated injection for myocardial perfusion and viability assessment. TI-201 SPECT with nitrate-augmented redistribution has significant logistical and economic advantages over traditional delayed redistribution with TI-201 repeated injection.