Kaveh Vejdani MD, Presenter: Nothing to Disclose

Razi Muzaffar DO, Abstract Co-Author: Nothing to Disclose

Medhat M. Osman MD, Abstract Co-Author: Speaker, Koninklijke Philips NV

Hannah Sweet, Abstract Co-Author: Nothing to Disclose

Harsh C Gandhi BS,MSc, Abstract Co-Author: Nothing to Disclose

To examine the effect of CT attenuation correction on quantitation and visual semi-quantitative interpretation of DaTscan (123I-ioflupane) brain SPECT images; and to evaluate inter-rater reliability in 123I-ioflupane (DaTscan) brain SPECT image processing.

123I-ioflupane (DaTscan) brain SPECT and SPECT/CT images from 21 patients were analyzed retrospectively. Axial reconstruction was performed with and without attenuation correction (AC and NAC respectively). On each of the AC and NAC stack, axial slices passing through the striatum were summed into a representative image. Ioflupane uptake in bilateral striata was quantified using manually drawn regions of interest (ROI). The occipital lobes were used as background for specific binding ratio (SBR) calculation. SBR was defined as striatal counts minus background counts, divided by background counts. SBR values and percent SBR asymmetry were compared between AC and NAC images. Ioflupane visual uptake level (VUL) in bilateral striata was graded on a scale of 0 to 5 and was correlated with SBR on both AC and NAC images.

Striatal SBR values were significantly different (table 1) between AC and NAC images (p<0.001) but SBR asymmetry was not significantly different (p = 0.73). Visual estimation of striatal Ioflupane uptake (VUL) correlated moderately (r2 <0.7) with SBR (table 1). There was a high inter-rater reliability (r2 > 0.7) of SBR measurements (table 1).

CT AC significantly affects striatal ioflupane uptake measurement and yields higher SBR values. However, the degree of SBR asymmetry does not seem to be significantly affected by AC. Visual estimation of striatal ioflupane uptake does not correlate strongly with SBR. Quantitative SBR measurement with manual regions of interest is reproducible between two measurements.

Using attenuation correction for 123I-ioflupane brain SPECT has been recommended in the nuclear medicine community but its impact on quantitative assessment of the imaging remained unknown.

Vejdani, K, Muzaffar, R, Osman, M, Sweet, H, Gandhi, H, Impact of Attenuation Correction and Inter-rater Reliability on Quantitative 123I-ioflupane Brain SPECT.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14015077.html