Incidental Findings on Myocardial Perfusion SPECT Images

Abstract

Myocardial perfusion SPECT plays a crucial role in the diagnosis of coronary artery disease, providing a noninvasive tool to monitor ischemia and infarction. The findings can have a profound impact on diagnosis and management in these patients. However, incidental noncardiac findings on myocardial perfusion SPECT images can also affect management. These noncardiac subtleties are most often detected on the rotating raw SPECT images, which are often overlooked. The intent of this pictorial essay is to illustrate several subtle noncardiac abnormalities within nuclear cardiac imaging that can have an impact on patient management and follow-up.

INCIDENTAL DETECTION OF PREVIOUSLY UNKNOWN BREAST CANCER ON Tc-99m MIBI SCINTIGRAPHY

“…Tc-99m MIBI is especially used for myocardial perfusion imaging. However, incidental uptake on the areas of rotating raw SPE-CT images have also been detected (2). These findings may alert physicians to a condition that needs to be further examined, such as breast cancer.…”

“…It passively diffuses across the cell membrane and is sequestered in the mitochondria (1). Tc-99m MIBI scintigraphy is currently a commonly used diagnostic method for cardiac perfusion imaging (2). Myocardial perfusion scintigraphy is a noninvasive modality widely used in the evaluation of myocardial ischemia.…”

Incidental Non-cardiac Findings in Cardiovascular Imaging

“…Similar abnormalities may be identified on the CT performed for attenuation during SPECT or PET imaging. Some malignancies may also take up radiotracers during SPECT imaging, such as carcinoid tumours [ 20 , 21 ]. During cardiac MRI, lung abnormalities may be identified on any sequences, but in particular, axial and coronal images should be reviewed for the presence of INCF.…”

“…The identification of pulmonary fibrosis can be challenging on cardiac CT performed with contrast enhancement, and subsequent non-contrast CT imaging may be required to assess the lung parenchyma. Subtle changes of lung parenchymal abnormalities may also be identified on raw SPECT images, such as the flattening of the diaphragm in patients with COPD or reduced counts in patients with pleural effusions [ 20 ].…”

“…Malignancy including metastases or primary malignancy may also be identified. Subtle abnormalities may be identified in the liver during SPECT imaging such as reduced radiotracer uptake in patients with cirrhosis, multiple liver cysts or malignancy [ 20 ].…”