Subject(s)
Amyloidosis , Cardiomyopathies , Echocardiography/methods , Magnetic Resonance Imaging, Cine/methods , Radionuclide Imaging/methods , Technetium Tc 99m Pyrophosphate/pharmacology , Amyloidosis/diagnostic imaging , Amyloidosis/pathology , Cardiomyopathies/diagnostic imaging , Cardiomyopathies/pathology , Disease Progression , Early Diagnosis , Humans , Prognosis , Radiopharmaceuticals/pharmacologyABSTRACT
BACKGROUND: Technetium-99 m pyrophosphate protocols for transthyretin cardiac amyloidosis diagnosis have variably used 1- and 3-hour imaging time points. We investigated whether imaging at 1 hour with superior efficiency had comparable diagnostic accuracy as 3-hour imaging. METHODS: This is a registry analysis of patients with suspected transthyretin cardiac amyloidosis referred for technetium-99 m pyrophosphate at a single tertiary center from June 2015 through January 2019. Patients underwent planar and single-photon emission computed tomography (SPECT) imaging at 1 and 3 hours. A positive Tc-99m pyrophosphate study was defined by the presence of diffuse myocardial tracer uptake on SPECT. For planar imaging, visual semiquantitative (grades 0-3, ≥2 considered positive) and quantitative heart to contralateral ratios (≥1.5 considered positive) were used. RESULTS: Two hundred thirty-three patients (69% men; median age, 77 [69-83] years) underwent the study protocol. There were 60 (25.8%) patients with diffuse myocardial uptake, 1 (0.4%) with regional uptake, and 172 (73.8%) with no myocardial uptake. Results of SPECT were identical at 1 and 3 hours. Planar imaging at 1 hour had 98% sensitivity and 96% specificity. Planar grade 0 uptake or heart to contralateral ratio ≤1.2 and planar grade 3 uptake or heart to contralateral ratio ≥2.0 were always associated with negative and positive SPECT, respectively. For planar grades 1 and 2 uptake and heart to contralateral ratio 1.3 to 1.9, SPECT was needed to make a diagnosis. No patient with light-chain cardiac amyloidosis had positive SPECT. CONCLUSIONS: An efficient 1-hour technetium-99 m pyrophosphate protocol had comparable diagnostic performance to a 3-hour protocol.
Subject(s)
Amyloid Neuropathies, Familial/diagnosis , Cardiomyopathies/diagnosis , Technetium Tc 99m Pyrophosphate/pharmacology , Tomography, Emission-Computed, Single-Photon/methods , Aged , Aged, 80 and over , Diagnosis, Differential , Female , Follow-Up Studies , Humans , Male , Radiopharmaceuticals/pharmacology , Reproducibility of Results , Retrospective Studies , Time FactorsABSTRACT
OBJECTIVE: to specify frequency, patterns and diagnostic significance of extraosseous soft tissue findings in 99mTc-pyrophosphate skeletal scintigraphy. MATERIAL AND METHODS: Results of skeletal scintigraphy from 1060 patients (447 men, 613 women) were analyzed. Scanning in "whole body" mode started in 3-4 hours after 740 MBq of radiotracer activity intravenous administration, and performed in anterior and posterior projections in continuous table motion mode at rate of 6-8 cm per minute. Single photon emission computed tomography/computed tomography (SPECT/CT) was additionally performed when necessary. RESULTS: Extraosseous scintigraphic findings were discovered in 161 (15.2%) patients, they can be divided into three categories: nephrourological (7.7%), soft tissue (5.4%) and artifacts (2.1%). First category included anatomical and functional changes in the urinary system (kidney location anomalies and nonobstructive uropathies). SPECT/CT was performed to differentiate calycostasis in the projection of the upper group of calyces and focal changes of the ribs. Soft tissue extrarenal findings included diffuse or focal RP hyperfixation within breasts (29 patients), thyroid glands (15), myocardium (5), scrotum (4) and abdominal cavity (4). Symmetrical increased RP accumulation in breast or thyroid lobes was accepted as normal. Pathologic soft tissue findings in 11 patients were verified by history or instrumental data: breast cancer (2), testicular cancer (1), nodular goiter (2), uterine fibroids (2), primary cancer with liver metastases (1), association of "hot kidney" phenomenon with chemotherapy (2), and "superscan" phenomenon with myelofibrosis (1). Causes of radiotracer artifacts in the liver and spleen (14) were of radiopharmaceutical factors, in axillary lymph node (7)--partially infiltrative radiopharmaceuticals administration, in the colon (1)--previous myocardial perfusion scintigraphy. CONCLUSION: Analysis and interpretation of abnormal extraosseous findings in skeletal scintigraphy is an essential component of additional diagnostic information, that can influence subsequent diagnostic and therapeutic tactics.
Subject(s)
Bone and Bones/diagnostic imaging , Radionuclide Imaging/methods , Technetium Tc 99m Pyrophosphate/pharmacology , Tomography, Emission-Computed, Single-Photon/methods , Adult , Artifacts , Breast Neoplasms/diagnostic imaging , Female , Humans , Incidental Findings , Male , Middle Aged , Outcome Assessment, Health Care , Radiopharmaceuticals/pharmacology , Soft Tissue Neoplasms/diagnostic imaging , Thyroid Diseases/diagnostic imaging , Urogenital Neoplasms/diagnostic imagingABSTRACT
A clinical observation of focal accumulation of 99(m)Tc-pyrophosphate in aortic aneurysm, simulating skeletal pathology of the lumbar vertebra in planar scintigraphy mode, is presented. Additional single-photon emission computed tomography combined with computed tomography-something view allowed to confirm that the radiotracer uptake focus was localized in the distal part of the aneurysm, in the zone of lumen subocclusion by a calcified thrombus. It is suggested that the local tracer accumulation is not only due to calcification but also due to inflammatory, a factor that plays a role in the genesis of aortic aneurysm.
