Diagnostic Concordance of Immediate Versus 1-Hour Technetium-99m Hydroxymethylene Diphosphonate Scintigraphy in Suspected Transthyretin Amyloid Cardiomyopathy
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Background
Bone-avid tracer myocardial scintigraphy for the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM) has traditionally employed imaging at one or 3-hour intervals. Technetium-99m hydroxymethylene diphosphonate ( 99m Tc-HDP) has unique characteristics that may enable earlier imaging. We investigated the diagnostic concordance of immediate versus 1-hour acquisitions.
Methods
Consecutive patients with suspected ATTR-CM underwent planar imaging and SPECT/CT immediately and at 1-hour following the administration of 99m Tc-HDP. Perugini grades and heart to contralateral lung (H/CL) ratios were assessed. Target-to-background ratios (TBRs) were calculated on the SPECT/CT acquisitions using the left ventricular (LV) septum and three background regions: aorta, LV blood-pool, and vertebrae. We assessed diagnostic concordance using Cohen’s Kappa ( κ ), temporal stability using paired t-tests, and correlation between timepoints using Pearson’s coefficient ( r ). The 1-hour SPECT/CT interpretation served as the protocol reference standard.
Results
Forty-eight patients (83% male; median age, 80 [73–85] years) were evaluated. One-hour SPECT/CT identified 19 positive and 29 negative cases. Immediate SPECT/CT demonstrated 100% diagnostic concordance with the 1-hour reference standard ( κ = 1.000; p < 0.001). The LV septum/LV Blood-Pool TBR showed the highest correlation ( r = 0.956; p < 0.001). The LV Septum/Aorta TBR demonstrated high correlation (r = 0.918; p < 0.001) and remained stable in the ATTR-negative cohort (−0.02; p = 0.54). Significant decreases in the LV Septum/Vertebrae TBR were observed in the ATTR-negative (−0.55; p < 0.001) and ATTR-positive cohorts (−1.14; p < 0.001).
Conclusions
Immediate 99m Tc-HDP SPECT/CT is diagnostically concordant with standard 1-hour protocols and accurately reproduces 1-hour acquisitions in cases of suspected ATTR-CM. This expedited approach may improve nuclear laboratory throughput and patient satisfaction.
