MIP images improve trainee accuracy, speed and confidence in the interpretation of DaTscans

Introduction: DaTscan allows for striatal dopamine transporter visualization by using single-photon emission computed tomography (SPECT) brain imaging, attempting to qualify patients with presumed Parkinsonism disorders. DaTscans demonstrate positive findings by illustrating abnormal intensity and asymmetry of radiotracer uptake in the caudate and putamen on SPECT imaging. Challenges in DaTscan interpretation include variations in the obliquity of the scan, patient motion, patient positioning, and scanner quality. In an effort to mitigate these variations, we employ maximum intensity projection (MIP) images in the evaluation of DaTscans, in addition to the standard axial SPECT images. We hypothesize that the use of MIP images will increase trainee interpretation accuracy, speed and diagnostic certainty.

Methods: 50 deidentified DaTscan axial SPECT images and MIP images were presented to four Radiology residents of varying training levels and two Nuclear Medicine staff physician. First the entire dataset of 50 axial SPECT sequences were shown one at a time and then the 50 MIP images were shown one at a time to the interpreters. Interpreters reported the positive/negative status and confidence level (1-3) for each of the axial SPECT sequences and MIP images. We then recorded the interpreter's overall confidence and ease of use for the cohort. We judged the trainee accuracy based on the consensus interpretation of the staff physician.

Results: Trainees' accuracy improved with utilization of MIP images compared with axial SPECT sequences (86% versus 81%). The speed of interpretations for all interpreters improved significantly with the MIP images compared with the axial SPECT sequences (67.9%). The confidence of interpretations for all interpreters also improved significantly with MIP versus axial SPECT sequences (4.7%). All interpreters reported increased confidence and ease of interpretation with the MIP images compared with the axial SPECT sequences.

Conclusions: Trainee accuracy improved with MIP images compared with standard axial SPECT sequences in the interpretation of DaTscans. Confidence, speed, and ease of interpretation for trainee and staff interpreters also improved.  Incorporating MIP images with DaTscans improves the confidence, speed, and accuracy of trainee and staff radiologists' interpretations. We propose that MIP images be included with all DaTscan image sets to improve diagnosis.