Michael Albert Thomas PhD, Presenter: Nothing to Disclose

Rajakumar Nagarajan PhD, Abstract Co-Author: Nothing to Disclose

Jonathan Furuyama, Abstract Co-Author: Nothing to Disclose

Daniel Jason Aaron Margolis MD, Abstract Co-Author: Research Grant, Siemens AG

Neil Wilson BS, Abstract Co-Author: Nothing to Disclose

Brian Burns, Abstract Co-Author: Nothing to Disclose

Manoj Kumar Sarma PhD, Abstract Co-Author: Nothing to Disclose

Robert E. Reiter MD, Abstract Co-Author: Nothing to Disclose

Steven Satish Raman MD, Abstract Co-Author: Nothing to Disclose

Prostate cancer (PCa) is the 2nd most common cancer in males. Hence, early detection and a reliable, non-invasive measure of PCa aggressiveness are necessary. Compressed Sensing (CS) has revolutionized medical imaging by allowing for the reconstruction of undersampled data sets. The CS-based approaches is well-suited for MRSI such as the recently proposed four-dimensional (4D) echoplanar J-resolved spectroscopic imaging (EP-JRESI). The goal of the present study is to demonstrate the feasibility of implementing a non-uniformly undersampled (NUS) EP-JRESI sequence with CS-based reconstruction and evaluating this technique in PCa and healthy prostates.

Seven healthy human subjects and 3 PCa patients were investigated so far using the NUS EP-JRESI sequence implemented on a Siemens 3T Tim-Trio MRI/MRS scanner. The acquired 4D MRSI data had 2 spatial and 2 spectral dimensions. The acquisition parameters were: TR/TE = 1.5s/30ms, 512t2 complex points, F2/F1 bandwidth of 1190Hz/1000Hz, 1cc voxel size, 16kx using the EPI read-out train, and 64t1 increments and 16ky undersampled at 25%. Acceleration of the kx/t2 spatial/spectral dimensions was achieved by an echo-planar spectroscopic imaging (EPSI) read-out train. An external body matrix assembly was used with the three PCa patients and an endorectal coil with the seven healthy males, both driven in “receive” mode.

Multi-voxel 2D spectra recorded in seven healthy volunteers and three patients showed additional metabolite resonances compared to those reported using conventional MRSI techniques: citrate (Cit), creatine (Cr), choline (Cho), spermine (Spm), myo-inositol (mI), scyllo-inositol (Scy), taurine (Tau), glutamate (Glu) and glutamine (Gln). Pilot results so far demonstrate that altered levels of several of these resonances can be recorded successfully using the NUS EP-JRESI sequence in PCa patients in a shorter acquisition duration.

Current work demonstrates two major accomplishments: 1) Accelerating the 4D EP-JRESI sequence by a factor of 4 along the incremented spatial/spectral dimensions along with the directly acquired dimensions. 2) Acquiring multi-voxel 2D J-resolved spectra with 1cc voxels in PCa in 6-12 minutes.

A major outcome of this study is demonstrating the feasibility of implementing an accelerated multi-voxel based 2D MR Spectroscopic technique in prostate pathology with an acceptable voxel resolution.

Thomas, M, Nagarajan, R, Furuyama, J, Margolis, D, Wilson, N, Burns, B, Sarma, M, Reiter, R, Raman, S, Compressed Sensing For Echo-Planar J-Resolved Magnetic Resonance Spectroscopic Imaging: Pilot Findings in Prostate Cancer.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043888.html