Optimizing the Diagnosis of ATTR-CM: Updates in Imaging and Best Practices-Interpretation and Reporting Cardiac Scintigraphy with Bone-avid Tracers

Interpretation and Reporting Cardiac Scintigraphy with Bone-avid Tracers

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The document provides guidelines for interpreting and reporting cardiac scintigraphy with bone-avid tracers in suspected transthyretin cardiac amyloidosis (ATTR-CA). Cardiac scintigraphy using tracers like Tc-99m PYP, Tc-99m DPD, and Tc-99m HMDP is crucial for non-invasive diagnosis of ATTR-CA. The emphasis has shifted from planar imaging to tomographic evaluation via SPECT or SPECT/CT, which allows for more accurate visualization of tracer uptake in the myocardium.<br /><br />The stepwise interpretation approach involves confirming myocardial tracer uptake using SPECT imaging, assessing visual uptake with the Perugini scoring system, and optionally quantifying uptake through the heart-to-contralateral lung (H/CL) ratio. The importance of ruling out light chain amyloidosis (AL-CA) through serum and urine testing before confirming ATTR-CA is highlighted, as myocardial tracer uptake can occur in both conditions.<br /><br />Guidelines suggest imaging at 1 or 3 hours post-injection of tracers, with repeat imaging at 3 hours if necessary due to excessive blood pool activity. The document warns of false positives or negatives due to factors like blood pool activity, myocardial injury, and genetic mutations, advising caution and comprehensive evaluation.<br /><br />Standardized reporting involves documenting patient demographics, methods, findings, conclusions, and recommendations for further testing. Two case studies illustrate positive and negative imaging results, emphasizing the role of imaging in clinical decision-making.<br /><br />Overall, the document underscores the importance of precise imaging protocol adherence and comprehensive reporting to ensure accurate diagnosis of cardiac conditions, especially discerning ATTR-CA from AL-CA to guide appropriate treatment strategies.

Keywords

cardiac scintigraphy

bone-avid tracers

transthyretin cardiac amyloidosis

Tc-99m PYP

SPECT imaging

Perugini scoring system

H/CL ratio

light chain amyloidosis

diagnostic guidelines

imaging protocol