Diagnostic value of heart-to-mediastinum ratio in 99mTc-pyrophospate SPECT/CT for transthyretin cardiac amyloidosis

Ikoma, Takenori; Ohtani, Hayato; Ohno, K; Iguchi, Keisuke; Suwa, Kenichiro; Sawada, Michifumi; Tanahashi, Yoshikatsu; Sakamoto, Atsushi; Saotome, Masao; Ichikawa, Shintaro; Goshima, Satoshi; Maekawa, Yuichiro

doi:10.1007/s12350-022-03180-5

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…A previous study using the H/M ratio calculated from the maximum standardized uptake value (SUVmax) on SPECT images reported that a cutoff value of 1. 41 has considerably high sensitivity and specificity for identifying patients with ATTR-CA (7). Another SPECT study suggested that myocardial PYP uptake exceeding 1.2 times the SUVmax of the aortic blood pool may be optimal for detecting abnormal uptake (15).…”

Section: Discussionmentioning

confidence: 99%

“…Recently, the heart-to-mediastinum uptake (H/M) ratio has been proposed as a semiquantitative measure of the myocardial PYP uptake on SPECT images to solve the diagnostic problem of the H/CL ratio, which is calculated as the ratio of PYP uptake between the heart and mediastinum under the aortic arch (7). In that study, an H/M ratio of >1.41 on SPECT images identified patients with ATTR-CA with 100% sensitivity and 93.3% specificity, suggesting that the H/M ratio may have higher specificity than the H/CL ratio in detecting myocardial PYP uptake.…”

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confidence: 99%

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Lateral Planar Imaging of <sup>99m</sup>Tc-pyrophosphate Scintigraphy in Patients with Suspected Transthyretin Cardiac Amyloidosis

Saitou,

Aikawa,

Manabe

et al. 2024

Annals of Nuclear Cardiology

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Background: Lateral planar 99mTc-pyrophosphate (PYP) imaging is recommended as a standardized acquisition method because it helps separate extracardiac uptake from the myocardium. We evaluated its discriminatory performance in detecting myocardial PYP uptake, using single-photon emission computed tomography (SPECT) as a reference standard. Methods: We retrospectively evaluated 170 patients who underwent PYP imaging for suspected transthyretin cardiac amyloidosis. Anterior and lateral planar imaging and SPECT were performed 3 h after PYP administration. The myocardial PYP uptake on planar and SPECT images was visually assessed and quantified using the heart-to-contralateral lung uptake (H/CL) ratio. The heart-to-mediastinum uptake (H/M) ratio was calculated as the mean count of the region of interest in the heart divided by that in the superior mediastinum on lateral planar images. Results: Patients with PYP SPECT-positive results had significantly higher H/M ratios at 3 h than those with PYP SPECT-negative results (1. 23 [interquartile range: IQR, 1. 15-1. 43] vs. 1. 08 [IQR, 1. 02-1. 16]; P < 0. 001). A reclassification analysis that added the H/M ratio to visual scores for detecting positive PYP SPECT yielded a significant improvement with a net reclassification improvement (NRI) of 0.56 (95%CI, 0.25-0.87; P<0.001) and integrated discrimination improvement (IDI) of 0.038 (95%CI, 0.005-0.072; P=0.026). The H/M ratio significantly improved the predictive ability of SPECT findings based on the visual scores and H/CL ratio with an NRI of 0.49 (95%CI, 0.18-0.81; P=0.003) and IDI of 0.036 (95%CI, 0.004-0.069; P=0.029). Conclusions: Adding the H/M ratio derived from lateral planar PYP imaging to visual scores or the H/CL ratio on anterior planar images improved the accuracy of detecting significant myocardial uptake on SPECT.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Lateral Planar Imaging of <sup>99m</sup>Tc-pyrophosphate Scintigraphy in Patients with Suspected Transthyretin Cardiac Amyloidosis

Saitou,

Aikawa,

Manabe

et al. 2024

Annals of Nuclear Cardiology

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“…The quantitative method uses the heart to contralateral lung (H/CL) ratio, where a ratio greater than 1.5 suggests ATTR-CA. In recent years and with the increased utilization of SPECT, H/CL ratio has fallen out of favor due to its limited prognostic value and false positivity due to bood pooling [21,22].…”

Section: Technetium-labeled Cardiac Scintigraphymentioning

confidence: 99%

Nuclear imaging techniques for cardiac amyloidosis

Saad,

Al-Mallah

2024

Current Opinion in Cardiology

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Purpose of review Cardiac amyloidosis is a condition marked by the misfolding of precursor proteins into insoluble amyloid fibrils, leading to restrictive cardiomyopathy and heart failure symptoms. This review discusses advancements in nuclear imaging techniques that enhance the diagnosis and guide the management of cardiac amyloidosis, addressing the critical need for early and accurate detection in clinical practice. Recent findings Recent studies and guidelines emphasizes the pivotal role of nuclear imaging techniques in diagnosing cardiac amyloidosis. Cardiac scintigraphy, using bone-avid tracers like 99mTc-PYP, 99mTc-DPD, and 99mTc-HMDP, is instrumental in distinguishing between transthyretin amyloidosis and light chain amyloidosis. PET, with tracers such as 11C-Pittsburgh Compound B (11C-PiB) and 18F-Florbetapir, offers significant potential in measuring amyloid burden and monitoring disease progression, providing detailed insights into the myocardial involvement. Summary The advancements in nuclear imaging techniques significantly impact the management of cardiac amyloidosis. These methods allow for a more accurate diagnosis, detailed assessment of disease extent, and better differentiation between amyloidosis types, which are crucial for tailoring treatment approaches. The integration of these techniques into clinical practice is essential for improving patient outcomes and advancing research in cardiac amyloidosis.

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“…In the current issue of the Journal, Ikoma et al 8 have tested the diagnostic accuracy of the heart-to-mediastinum ratio (H/M ratio) with endomyocardial biopsy as the standard of reference in 30 patients undergoing 99m Tc-pyrophosphate (PYP) SPECT/CT. Half of the patients (n = 15) had biopsy-proven cardiac ATTR amyloidosis; the rest of the patients suffered from dilated cardiomyopathy, hypertrophic cardiomyopathy, aortic stenosis, hypertensive heart disease, cardiac sarcoidosis, cardiac light chain (AL) amyloidosis and isolated atrial amyloidosis.…”

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confidence: 99%