Incidental cardiac uptake in bone scintigraphy: increased importance and association with cardiac amyloidosis

Abstract

Extraosseous radiotracer uptake during bone scintigraphy must be carefully assessed and it offers the potential to detect previously undiagnosed disease processes. A range of neoplastic, metabolic, traumatic, ischaemic and inflammatory disorders can cause soft tissue accumulation of bone avid radiopharmaceuticals. Accordingly, cardiac uptake in bone scintigraphy has a broad differential diagnosis and is commonly attributed to ischaemia/infarction related to coronary artery disease. However, there has been renewed focus on incidental cardiac uptake in recent years in light of significant developments in the diagnosis and management of cardiac amyloidosis.

Figure 1.

Whole body bone scan in case 1. Whole body planar images were acquired 5 min (left two images) and 3 h (right two images) after intravenous 99mTc-DPD radiotracer administration. Incidental significant cardiac uptake is seen, raising concern for cardiac ATTR amyloidosis. Otherwise, there is expected radiotracer accumulation in the skeleton and urinary tract and additional sites of focal uptake related to degenerative disease at multiple joints. Focal uptake at the injection site in the right arm is also demonstrated.

Figure 2.

Cardiac scintigraphy in case 1. Anterior (upper image) and posterior (lower image) planar thoracic images were acquired 3 h after 99mTc-DPD administration. Severe myocardial uptake (Perugini 3 – uptake greater than rib uptake), predominantly in the left ventricle, is demonstrated compatible with the diagnosis of cardiac ATTR amyloidosis in a patient with diastolic dysfunction and absence of AL amyloidosis monoclonal gammopathy.

Figure 3.

Axial CT image in case 2. Ill-defined sclerotic lesion with the T10 vertebral body (red arrow) incidentally detected on abdominal CT for an unrelated indication. Further investigation with bone scintigraphy was arranged.

Figure 4.

Whole body bone scan in case 2. There is incidental significant cardiac uptake raising concern for cardiac ATTR amyloidosis. Otherwise, there is expected radiotracer accumulation in the skeleton and urinary tract and additional sites of focal uptake related to degenerative disease at multiple joints. Focal uptake at the injection site in the right hand is also demonstrated.

Figure 5.

Cardiac scintigraphy in case 2. Anterior and posterior planar thoracic images, acquired 3 h after 99mTc-DPD administration, demonstrate severe myocardial uptake (Perugini 3 – uptake greater than rib uptake) predominantly in the left ventricle, compatible with the diagnosis of cardiac ATTR amyloidosis. Diagnosis was confirmed on endomyocardial biopsy in this case.

Figure 6.

Serial whole-body bone scans in case 3. The initial scan (a), performed 8 years prior to cardiac ATTR amyloidosis diagnosis as part of prostate cancer staging, demonstrates mild/moderate cardiac uptake (Perugini 2). Subsequent bone scintigraphy performed 4 years (b) and 3 years (c) prior to cardiac ATTR amyloidosis diagnosis shows severe cardiac uptake (Perugini 3). A significant increase in the extent of DPD uptake is seen when compared to the initial bone scan.

Figure 7.

Cardiac scintigraphy in case 3. Anterior and posterior planar thoracic images, acquired 3 h after 99mTc-DPD administration, demonstrate severe myocardial uptake (Perugini 3 – uptake greater than rib uptake) predominantly in the left ventricle, compatible with the diagnosis of cardiac ATTR amyloidosis. This study was performed 8 years after initial whole-body bone scan and 3/4 years after