PT - JOURNAL ARTICLE AU - Ishan Garg AU - Andrew Hoffman AU - Martha Grogan AU - John Askew AU - Angela Dispenzieri AU - Steven Zeldenrust AU - Stephen Broski AU - Ann Packard AU - Geoffrey Johnson TI - 3-D PYP Score for 3-hour uptake <sup>99m</sup>Tc Pyrophosphate SPECT-CT for Transthyretin Amyloid Cardiomyopathy DP - 2017 May 01 TA - Journal of Nuclear Medicine PG - 35--35 VI - 58 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/58/supplement_1/35.short 4100 - http://jnm.snmjournals.org/content/58/supplement_1/35.full SO - J Nucl Med2017 May 01; 58 AB - 35Objectives: The current gold standard for diagnosis of amyloid cardiomyopathy (A-CM) is endomyocardial biopsy (EMB). Bone radiotracer based scintigraphy has re-emerged as an effective non-invasive procedure for diagnosing A-CM, specifically transthyretin amyloid cardiomyopathy (ATTR-CM). The purpose of our study was to evaluate the diagnostic accuracy of a new combined single-photon emission computed tomography and computed tomography (SPECT-CT) (3-D imaging) based quantitative method for diagnosing ATTR-CM and compare it with the current standard planar scintigraphy (2-D imaging) method, the heart-to-contralateral side (HCL) ratio.Methods: In this institutional review board-approved, HIPAA-compliant retrospective study, our institutional SPECT-CT database (01/01/2011 to 09/26/2016) included 189 sequential clinical PYP scans in 178 patients. Eligibility for this study required either an EMB confirming amyloidosis or lack of amyloidosis or at least one non-cardiac tissue biopsy confirming amyloidosis with echocardiographic evidence of infiltrative cardiomyopathy (in the absence of any other pathological cause of cardiomyopathy). We identified 63 scans in 62 patients: 46 ATTR (25 EMB proven; 21 surrogate tissue biopsy); 12 light-chain amyloid (AL) (7 EMB; 5 surrogate biopsy); and 4 non-amyloid cases (all EMB proven). Three cases in which minimal amyloid deposition (ATTR) was incidentally detected on septal myomectomy tissue (without evidence of A-CM) were excluded. The 3-D (volumetric) quantitative analysis was done on SPECT-CT images, taken 3 hours after injection of PYP, by drawing volumes of interest (VOIs) around the entire left ventricle (LV) and within the right atrium (RA) blood pool. Mean uptake of the LV (LVmean) and RA (RAmean) VOIs were used to create a LVmean:RAmean ratio (3-D PYP score). The 2-D quantitative analysis was performed on planar scintigraphy by dividing the counts in a region of interest (ROI) drawn over the heart by counts in the same sized ROI placed in the contralateral chest, calculating an HCL ratio.Results: ATTR-CM patients (n=43) were older than non-ATTR-CM patients (n=16) at the time of diagnosis (mean age: 74.2 years; range: 45-95 versus 68.9 years; 44-87). The patients with ATTR-CM had a significantly higher 3-D PYP score and HCL ratio than patients with non-ATTR-CM (mean±SD: 1.7±0.46 versus 0.8±0.17; P&lt;0.001 for 3-D PYP score and 1.6±0.28 versus 1.1±0.16; P&lt;0.001 for HCL). The diagnostic performance of SPECT-CT using 3-D PYP score of 蠅1.1 versus planar scintigraphy using HCL ratio of 蠅1.3 for detecting ATTR-CM was: sensitivity 97.7% versus 91.1% and specificity 93.8% versus 80.0%.Conclusion: SPECT-CT based 3-D PYP score showed an excellent sensitivity and specificity and a better diagnostic performance than the planar scintigraphy based HCL ratio for detecting ATTR-CM. Imaging at 3 hours after injection and using SPECT-CT imaging, may result in higher sensitivity for ATTR-CM by allowing background blood pool activity to resolve and avoiding overlying bony structures respectively. Research Support: None