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Introducción Los radiotrazadores con afinidad ósea como el [99mTc]Tc-DPD han demostrado una alta sensibilidad y especificidad en el diagnóstico no invasivo de la amiloidosis cardíaca (AC) por transtirretina (ATTR-AC). Este estudio tiene como objetivo validar el uso de la SPECT/TC y evaluar la utilidad de la cuantificación de la captación (cargaDPD) en el tejido miocárdico como información potencial sobre la carga amiloide. Métodos Se trata de un análisis retrospectivo de 46 pacientes con sospecha de AC, en el que 23 casos con ATTR-AC fueron sometidos a dos métodos de cuantificación para estimar la carga amiloide (cargaDPD) a través de imágenes planares y de una SPECT/TC. Resultados La SPECT/TC aportó un valor añadido significativo en el diagnóstico del paciente con AC (p<0,05). La estimación de la carga amiloide comprobó que la pared del VI más afectada es el tabique interventricular en la mayoría de los casos, y la existencia de una relación significativa entre la captación de Perugini y la carga de DPD. Conclusiones Validamos la necesidad de la SPECT/TC como complemento de la imagen planar en el diagnóstico de la AC-TTR. Por su parte, el cálculo de la carga amiloide continúa siendo un área de investigación compleja y requiere de más estudios, con un mayor número de pacientes, que permitan validar un método estandarizado de cuantificación de la carga de amiloide, tanto para el diagnóstico como para el seguimiento del tratamiento (AU)

Background Bone tracers such as [99mTc]Tc-DPD have shown high sensitivity and specificity in the non-invasive diagnosis of transthyretin cardiac amyloidosis (ATTR-AC). This study aims to validate SPECT/CT and assess the usefulness of uptake quantification (burdenDPD) in the myocardial tissue as potential information on the amyloid burden. Methods In a retrospective analysis of 46 patients with suspected CA, 23 cases with ATTR-AC had two quantification methods conducted to estimate amyloid burden (burdenDPD) through planar scintigraphic scans and a SPECT/CT. Results SPECT/CT significantly provided an added value in the patient's diagnosis with CA (P<.05). The estimation of the amyloid burden substantiated that the most affected wall of the LV is the interventricular septum in most cases and the existence of a significant relationship between the Perugini score uptake and the burdenDPD. Conclusions We validate the need for SPECT/CT to complement planar imaging in diagnosing ATTR-AC. For its part, quantifying the amyloid load continues to be a complex area of research. It requires further studies with a larger number of patients to validate a standardized method of amyloid load quantification, both for diagnosis and treatment monitoring (AU)

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BACKGROUND: Bone tracers such as 99mTc-DPD have shown high sensitivity and specificity in the non-invasive diagnosis of transthyretin cardiac amyloidosis (ATTR-CA). This study aims to validate SPECT/CT and assess the usefulness of uptake quantification (DPDload) in the myocardial tissue as potential information on the amyloid burden. METHODS: In a retrospective analysis of 46 patients with suspected CA, 23 cases with ATTR-CA had two quantification methods conducted to estimate amyloid burden (DPDload) through planar scintigraphic scans and a SPECT/CT. RESULTS: SPECT/CT significantly provided an added value in the patient's diagnosis with CA (P<.05). The estimation of the amyloid burden substantiated that the most affected wall of the LV is the interventricular septum in most cases and the existence of a significant relationship between the Perugini score uptake and the DPDload. CONCLUSIONS: We validate the need for SPECT/CT to complement planar imaging in diagnosing ATTR-CA. For its part, quantifying the amyloid load continues to be a complex area of research. It requires further studies with a larger number of patients to validate a standardized method of amyloid load quantification, both for diagnosis and treatment monitoring.

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OBJECTIVE: Our aim is to validate the process steps implemented by the French CATI platform to assess amyloid status, obtained from 18F-Florbetapir PET scans, in a cohort of 318 cognitively normal subjects participating in the INSIGHT-preAD study. Our objective was to develop a method with partial volume effect correction (PVEC) on untransformed PET images, using an automated pipeline ("RACHEL") adapted to large series of patients and including quality checks of results. METHODS: We compared RACHEL using different options (with and without PVEC, different sets of regions of interest), to two other methods validated in the literature, referred as the "AVID" and "CAEN" methods. A standard uptake value ratio (SUVR) was obtained with the different methods for participants to another French study, IMAP, including 26 normal elderly controls (NEC), 11 patients with mild cognitive impairment (MCI) and 16 patients with Alzheimer's disease (AD). We determined two cutoffs for RACHEL method by linear correlation with the other methods and applied them to the INSIGHT-preAD subjects. RESULTS: RACHEL including PVEC and a combination of the whole cerebellum and the pons as a reference region allowed the best discrimination between NEC and AD participants. A strong linear correlation was found between RACHEL and the other two methods and yielded the two cutoffs of 0.79 and 0.88. According to the more conservative threshold, 19.8% of the INSIGHT-preAD subjects would be considered amyloid positive, and 27.7% according to the more liberal threshold. CONCLUSIONS: With our method, we clearly discriminated between NEC with negative amyloid status and patients with clinical AD. Using a linear correlation with other validated cutoffs, we could infer our own positivity thresholds and apply them to an independent population. This method might be useful to the community, especially when the optimal cutoff could not be obtained from a population of healthy young adults or from correlation with post-mortem results.

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