Using PETCT Bone Scan Dynamic Data to Evaluate Tibia Remodeling When a Taylor Spatial Frame Is Used: Short and Longer Term Differences

Abstract EN

Eighteen consecutive patients, treated with a Taylor Spatial Frame for complex tibia conditions, gave their informed consent to undergo Na18F− PET/CT bone scans.

We present a Patlak-like analysis utilizing an approximated blood time-activity curve eliminating the need for blood aliquots.

Additionally, standardized uptake values (SUV) derived from dynamic acquisitions were compared to this Patlak-like approach.

Spherical volumes of interest (VOIs) were drawn to include broken bone, other (normal) bone, and muscle.

The SUV m ( t ) ( m = m a x , mean) and a series of slopes were computed as ( SUV m ( t i ) - SUV m ( t j ) ) / ( t i - t j ) , for pairs of time values t i and t j .

A Patlak-like analysis was performed for the same time values by computing ( ( VOI p ( t i ) / VOI e ( t i ) ) - ( VOI p ( t j ) / VOI e ( t j ) ) ) / ( t i - t j ) , where p = broken bone, other bone, and muscle and e = expected activity in a VOI.

Paired comparisons between Patlak-like and SUV m slopes showed good agreement by both linear regression and correlation coefficient analysis ( r = 84 % , r s = 78 % - SUV max , r = 92 % , and r s = 91 % - SUV mean ), suggesting static scans could substitute for dynamic studies.

Patlak-like slope differences of 0.1 min−1 or greater between examinations and SU V max differences of ~5 usually indicated good remodeling progress, while negative Patlak-like slope differences of −0.06 min−1 usually indicated poor remodeling progress in this cohort.