Diagnostic quality assessment of compressed sensing accelerated magnetic resonance neuroimaging. Issue 2 (18th January 2016) - Kayvanrad, Mohammad
Abstract : Purpose: To determine the efficacy of compressed sensing (CS) reconstructions for specific clinical magnetic resonance neuroimaging applications beyond more conventional acceleration techniques such as parallel imaging (PI) and low‐resolution acquisitions. Materials and Methods: Raw k ‐space data were acquired from five healthy volunteers on a 3T scanner using a 32‐channel head coil using T 2 ‐FLAIR, FIESTA‐C, time of flight (TOF), and spoiled gradient echo (SPGR) sequences. In a series of blinded studies, three radiologists independently evaluated CS, PI (GRAPPA), and low‐resolution images at up to 5× accelerations. Synthetic T 2 ‐FLAIR images with artificial lesions were used to assess diagnostic accuracy for CS reconstructions. Results: CS reconstructions were of diagnostically acceptable quality at up to 4× acceleration for T 2 ‐FLAIR and FIESTA‐C (average qualitative scores 3.7 and 4.3, respectively, on a 5‐point scale at 4× acceleration), and at up to 3× acceleration for TOF and SPGR (average scores 4.0 and 3.7, respectively, at 3× acceleration). The qualitative scores for CS reconstructions were significantly better than low‐resolution images for T 2 ‐FLAIR, FIESTA‐C, and TOF and significantly better than GRAPPA for TOF and SPGR (Wilcoxon signed rank test, P < 0.05) with no significant difference found otherwise. Diagnostic accuracy was acceptable for both CS and low‐resolution images at up to 3× acceleration (area under the ROC curve 0.97 and 0.96, respectively.) Conclusion: Mild to moderate accelerations are possible for those sequences by a combined CS and PI reconstruction. Nevertheless, for certain sequences/applications one might mildly reduce the acquisition time by appropriately reducing the imaging resolution rather than the more complicated CS reconstruction. J. Magn. Reson. Imaging 2016;44:433–444.