Tc-HMDP scintigraphy is as accurate as Tc-DPD or Tc-PYP, and may therefore de facto be considered a valuable tool for the diagnosis of TTR CA.

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Background. 99mTc-HMDP scintigraphy has proved its efficacy in non-invasive diagnosis of cardiac amyloidosis (CA) and is currently interpreted according to the Perugini qualitative assessment. Several semi-quantitative indices have been proposed to overcome inherent possible limitations of visual grading. Our aim was to comparatively evaluate six different indices and their diagnostic performance. Methods. We retrospectively reviewed scintigraphy of 76 patients (53 ATTR, 12 AL, 11 LVH) who underwent diagnostic evaluation at our centre. ROC-curve analysis was performed to identify optimal cutoff and relative diagnostic accuracy of six different indices (of which one was proposed for the first time), both in identifying CA patients and in discriminating patients according to their Perugini score. Results. Heart/Whole-body ratios proved to be the most accurate (100%) in identifying CA patients. Heart/Pelvis ratio (with soft tissue background correction) offered acceptable accuracy (98%), with the largest area under the curve (AUC) (0.98) in discriminating patients with Perugini ‡ 2. Heart/Contralateral Lung ratio confirmed to be exposed to confounding background noise in case of simultaneous lung uptake. Heart/Skull ratio had the worst performance, with six false-negative patients in ATTR identification. Conclusion. Heart/Whole-body ratios may be robust and effective semi-quantitative indices for the evaluation of CA by means of scintigraphy (J Nucl Cardiol 2019

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The study aim was to assess whether post-ejection thickening (PT) is an useful marker of viable myocardium in patients with chronic coronary artery disease. Twenty-three patients with critical coronary stenoses were submitted to dobutamine and dipyridamole stress-echocardiographies and dipyridamole-early-redistribution 201Tl SPECT within 15 days from coronary arteriography. They were selected for the presence of PT in segments that could be optimally studied by M-mode echocardiography and were hypo-akinetic in basal conditions. PT (occurring between end-ejection and mitral valve opening) was found in 58% of dysfunctional, critically perfused regions. Ninety-eight percent of the regions with PT and 6% of those without PT improved during low-dose dobutamine stress-echocardiography. Segments with PT had, respectively, higher and lower SPECT early-redistribution thallium activity than dysfunctional segments without PT and normokinetic regions. Therefore, regions with PT were viable and had a moderate decrease in coronary perfusion. Akinetic segments without PT did not show any inotropic reserve. After revascularization almost all the segments with PT improved. In conclusion, PT is a pattern of myocardial contraction easily detected by M-mode echocardiography in the clinical setting. If the results of this study are further confirmed, PT may become a sign for the recognition of myocardial viability.

99mTc-HMDP scintigraphy shows LR in about 60% of TTR subjects, related to the grade of HR. In AL amyloidosis LR is less frequent than in TTR amyloidosis suggesting an aetiological tropism that seems comparable to the already known TTR related cardiac tropism.

The risk of overlooking an underlying acute coronary syndrome remains an important challenge in patients complaining of chest pain but who have a non-diagnostic ECG (CP). Indeed, myocardial scintigraphy associated with exercise testing (exercise SPET) represents a valuable tool for excluding coronary artery disease (CAD) especially in patients with CP and delayed presentation to the emergency department. We sought to implement diagnoses of CAD in the early triage of CP patients by exercise gated SPET and compare diagnoses with outcomes. A total of 306 consecutive patients presenting with CP were found to be free of CAD at first line work-up including clinical evaluation, markers of myocardial injury and echocardiogram. These patients were studied initially with exercise SPET, and those with perfusion defects underwent angiography, while those with normal scans were discharged and followed up. Patients with positive scans (34%, n=105) had documented coronary stenoses in 43% (n=45); patients with negative scans (66%, n=201) had evidence of non-fatal coronary events at 6 months in 1.5% (n=3). When imaging was analysed with gating by the presence of transmural perfusion defects associated with wall motion abnormalities (n=86), only one patient, among 19 excluded, was recognized as having coronary stenosis by angiography (SPET vs gated SPET: negative predictive value 98.5% and 98%, respectively, P=NS; diagnostic accuracy 79% and 85%, respectively; P< or =0.03). Therefore, implementation of myocardial perfusion imaging in the early triage of patients with suspected acute coronary syndromes was effectively obtained by early exercise gated SPET, especially in patients with transmural myocardial perfusion defects associated with wall motion abnormalities.