Pathology and Laboratory Medicine.
Clin Nucl Med. 2023 Nov 1;48(11):e544-e546. doi: 10.1097/RLU.0000000000004869.
With documented high specificity, 99m Tc-pyrophosphate (PYP) scan enables the diagnosis of transthyretin cardiomyopathy to be made reliably without endomyocardial biopsy in patients who do not have monoclonal gammopathy. We report a case with extensive myocardial uptake of Perugini 3 score in the 3-hour 99m Tc-PYP myocardial SPECT that suggested transthyretin cardiac amyloidosis. However, a followed endomyocardial biopsy revealed no amyloid deposition. In this case, hyperphosphatemia was the most likely and presumptive cause of the false-positive 99m Tc-PYP scan. With this case, our experiences of the potential causes of false-positive results of 99m Tc-PYP are further expanded.
高特异性的 99mTc-焦磷酸盐（PYP）扫描可在无单克隆丙种球蛋白病的患者中可靠地诊断转甲状腺素蛋白心肌病，而无需进行心内膜心肌活检。我们报告了一例患者，其 99mTc-PYP 心肌 SPECT 在 3 小时时的 Perugini 3 评分显示广泛的心肌摄取，提示转甲状腺素蛋白心脏淀粉样变性。然而，随后的心肌活检显示无淀粉样沉积。在这种情况下，高磷血症可能是 99mTc-PYP 扫描假阳性的最可能和推测原因。通过这个病例，我们进一步扩展了 99mTc-PYP 假阳性结果的潜在原因的经验。
