Kye Jin Park MD, Presenter: Nothing to Disclose

Ho Sung Kim, Abstract Co-Author: Nothing to Disclose

Choong Gon Choi MD, Abstract Co-Author: Nothing to Disclose

Sang Joon Kim MD, Abstract Co-Author: Nothing to Disclose

To test the predictive value of the amide proton transfer (APT) imaging for differentiating recurrent tumor from treatment-related effect in patients with newly diagnosed glioblastomas.

Twenty-seven consecutive patients who showed new or enlarged, contrast-enhancing lesions within the radiation field after concurrent chemoradiotherapy were assessed by use of conventional MR imaging and APT imaging. APT imaging was performed using a gradient-echo multishot echo-planar imaging with thirty frequency offsets from + 5.0 to -5.0 ppm in 0.357 ppm step. The imaging parameters for APT were as follows: echo time = 6.2 msec; a flip angle = 25 degree; RF irradiation power = 1.0µT; and saturation duration = 70 msec/shot. The calculated APT asymmetry map at the offset of 3.5 ppm is called the APT image. The APT signal was measured on solid (APTsolid) and necrotic (APTnecrosis) of the enlarged contrast-enhancing lesion using 'hot-spot' method. Reference standard was pathology or clinico-radiologic diagnosis. The diagnostic performance of APT parameter was determined by receiver operating characteristic curve (ROC) and leave-one-out cross validation. Interreader agreement was assessed using intraclass correlation coefficient (ICC)

Twenty-seven patients were subsequently classified as having recurrent tumor (n=19) or treatment-related effect (n=8). There was statistically significant differences of APTsolid between the two groups (median, 0.055 vs 0.024; P = .007). But APTnecrosis was not significantly different between the two groups (median, 0.004 vs 0.009; P =.339). ROC curve and leave-one-out cross validation showed the APTsolid to be the predictor of recurrent tumor, with a sensitivity of 94.7% and a specificity of 71.4%. The ICCs for APTsolid and APTnecrosis were 0.81 and 0.89.

APT signal on solid portion of enlarged contrast-enhancing lesion can be used for differentiating recurrent tumor from treatment-related effect in patients with newly diagnosed glioblastomas.

APT imaging can be a potential, noninvasive imaging biomarker for monitoring treatment response in patients with newly diagnosed glioblastomas.

Park, K, Kim, H, Choi, C, Kim, S, Utility of Amide Proton Transfer Imaging for Prediction of Recurrent Glioblastoma: Initial Experience.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14011953.html