High-quality brain perfusion SPECT images may be achieved with a high-speed recording using 360° CZT camera

Objective The aim of this study was to compare brain perfusion SPECT obtained from a 360° CZT and a conventional Anger camera. Methods The 360° CZT camera utilizing a brain configuration, with 12 detectors surrounding the head, was compared to a 2-head Anger camera for count sensitivity and image quality on 30-min SPECT recordings from a brain phantom and from 99mTc-HMPAO brain perfusion in 2 groups of 21 patients investigated with the CZT and Anger cameras, respectively. Image reconstruction was adjusted according to image contrast for each camera. Results The CZT camera provided more than 2-fold increase in count sensitivity, as compared with the Anger camera, as well as (1) lower sharpness indexes, giving evidence of higher spatial resolution, for both peripheral/central brain structures, with respective median values of 5.2%/3.7% versus 2.4%/1.9% for CZT and Anger camera respectively in patients (p < 0.01), and 8.0%/6.9% versus 6.2%/3.7% on phantom; and (2) higher gray/white matter contrast on peripheral/central structures, with respective ratio median values of 1.56/1.35 versus 1.11/1.20 for CZT and Anger camera respectively in patients (p < 0.05), and 2.57/2.17 versus 1.40/1.12 on phantom; and (3) no change in noise level. Image quality, scored visually by experienced physicians, was also significantly higher on CZT than on the Anger camera (+ 80%, p < 0.01), and all these results were unchanged on the CZT images obtained with only a 15 min recording time. Conclusion The 360° CZT camera provides brain perfusion images of much higher quality than a conventional Anger camera, even with high-speed recordings, thus demonstrating the potential for repositioning brain perfusion SPECT to the forefront of brain imaging.

Evaluation of ATTR-cardiac amyloidosis employing Tc-99m pyrophosphate scintigraphy using planar, SPECT and gated SPECT imaging on dedicated cardiac CZT camera

Background/Introduction Recent recognition that ATTR cardiac amyloidosis (ATTR-CA) is not uncommon and the emergence of novel therapeutic opportunities resulted in the publication of “Expert Consensus Recommendations for Multimodality Imaging in Cardiac Amyloidosis”. However, almost all data were derived from general purpose NaI cameras, while new cardiac dedicated CZT cameras are becoming more widespread. Purpose To evaluate Tc-99m pyrophosphate (PYP) scintigraphy on D-SPECT cardio dedicated CZT camera (Spectrum Dynamics) in suspected ATTR-CA patients. Methods Seventy three consecutive patients suspected for ATTR-CA underwent planar (5 min), SPECT and gated SPECT (10 min, 8 bins) scintigraphy 89±26 min after injection of Tc99m-PYP 740 MBq, followed by late scintigraphy after 92±36 min in 65 consecutive patients. Perguini visual score, planar H/CL and SPECT derived H/CL ratio were evaluated by two blinded independent experienced readers. Diagnosis was based on visual interpretation after blood pool and monoclonal gammopathy were excluded. Results Very good to excellent planar and SPECT image quality was observed in almost all patients. PYP scintigraphy was positive in 6/73 patients, with left ventricular wall uptake clearly evident in the planar images of most patients. There was perfect agreement between readers regarding positive/negative interpretation. There was also substantial inter-observer agreement regarding the Perguini scoring (Cohen's k with linear weighting 0.819, 95% CI 0.701–0.937). Inter-observer agreement for H/CL ratio was also good (Pearson's correlation coefficient r(71)=0.873). SPECT and gated SPECT images were helpful only in one positive patient, and did not have an added value in any of the negative studies. Slightly better images were observed during late scintigraphy, but there was no change in interpretation, and H/CL ratio was not significantly changed (median difference −0.01, IQR 0.09). Alas, Inter-observer agreement of H/CL ratio was lower (Pearson's correlation coefficient r(64)=0.633). We also evaluated H/CL ratio derived from SPECT based application of the camera manufacturer. Agreement between early planar and early SPECT based H/CL ratio was good for both readers (r(69)=0.778 and r(66)=0.747), but inter-observer agreement was lower (r(66)=0.697). Conclusions ATTR PYP scintigraphy using cardiac dedicated CZT camera yielded excellent images in almost all patients, and uptake in the left ventricular wall could be easily identified in positive patients. Inter-observer agreement was excellent for both visual scoring and planar H/CL ratio. Early planar images were high quality, and limited additional diagnostic value was observed for both SPECT and gated SPECT scintigraphy and from later acquisition. Funding Acknowledgement Type of funding source: None

The detection of multivessel coronary artery disease: the value of quantitative myocardial blood flow and coronary flow reserve assessment

Background/Introduction The recent Cadmium-Zinc-Telluride (CZT) camera for MPS allows evaluating absolute MBF and CFR, possibly increasing the accuracy in detecting of multivessel CAD. Purpose To evaluate the accuracy of myocardial blood flow (MBF) and coronary flow reserve (CFR) quantitation performed by myocardial perfusion scintigraphy (MPS) for the detection of multivessel coronary artery disease (CAD). Methods Fifty-two patients with suspected or known CAD were enrolled in the study. All patients underwent CZT MPS, with the evaluation of MBF and CFR, followed by invasive coronary angiography. According to MPS and coronary angiography results, patients were divided into three groups. 1) non-obstructive CAD and normal MPS scan (control group) (n=7), 2) one vessel disease (1VD) (n=16), with significant coronary stenosis (≥70%) in one major epicardial coronary artery, 3) multivessel disease (MVD) group (n=29), with two or more major epicardial coronary arteries with (≥70%) stenoses or with ≥50% LMA stenosis. Results Absolute MBF and CFR were significantly reduced in patients with MVD as compared to those with 1VD [0.93 (IQR 0.76; 1.39) vs 1.94 (1.37; 2.21) ml/min/g, p=0.00012] and [1.4 (IQR 1.02; 1.85) vs 2.3 (1.8; 2.67), p=0.0004], respectively. The Syntax score correlated with global stress MBF (ρ=−0.64; p&lt;0.0001) and CFR (ρ=−0.53; p=0.0003). ROC analysis showed higher sensitivity and specificity for stress MBF (85.2% and 81%), and CFR (88.9% and 80%) compared with semiquantitative MPS stress evaluation (69% and 69%). Multivariate regression analysis showed that only stress MBF [OR (95% CI) 0.59 (0.42–0.82); p&lt;0.0003] was an independent predictor of MVD. Conclusion The use of absolute myocardial blood flow analysis with the CZT camera may identify high risk patients, such as those with multivessel disease. This approach could be used in clinical practice, increasing the accuracy in the evaluation of patients with known or suspected coronary artery disease. Funding Acknowledgement Type of funding source: None