WHOLE BODY VIEWS

Normal value cutoff is 10%, which is calculated as follows:

(Total body counts including background counts–total lung counts)/total body counts including background counts * 100. (1). Graph to the left in the figure. On the right hand side images of female 53 y/o, with COPD, without right to left shunt, with activity only in the lungs. No brain nor kidney tracer is demonstrated.

SJ Gandhi et al. (2) propose an alternative calculation:

In this method, normally less than 6% of Tc-99m MAA particles bypass the lung to lodge in other organs.

Likewise, El-Shabrawi MH et al. have a different way to estimate the right to left shunt, with the formula: activity outside thorax/activity outside plus inside thorax and a cutoff value of 0.278. HPS.

1 Kimiteru Ito, Kyoko Kurihara, Akihiko Ishibashi, Miyako Morooka, Takuya Mitsumoto, Ryogo Minamimoto and Kazuo Kubota. Cut-off value for normal versus abnormal right-to-left shunt percentages using 99mTc-macroaggregated albumin.Nuclear Medicine Communications 2011, 32:936–940.

2 Sunny J Gandhi, Sanjay Babu, Padma Subramanyam, and Palaniswamy Shanmuga Sundaram. Tc-99m macro aggregated albumin scintigraphy – indications other than pulmonary embolism: A pictorial essay. Indian J Nucl Med. 2013 Jul-Sep; 28(3): 152–162.

Home       Index     Lung Imaging      99 mTc-MAA Perfusion Scintigraphy           99 mTc  Ventilation Scintigraphy     Normal Images