Detection of prostate cancer local recurrence following radical prostatectomy: assessment using a continuously acquired radial golden-angle compressed sensing acquisition.

PURPOSE: To compare image quality and diagnostic performance for detecting local recurrence (LR) of prostate cancer after radical prostatectomy (RP) between standard dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and a high spatiotemporal resolution, continuously acquired Golden-angle RAdial Sparse Parallel acquisition employing compressed sensing reconstruction ("GRASP").

METHODS

A search was conducted for prostate MRI examinations performed in patients with PSA ≥0.2 ng/mL after RP in whom follow-up evaluation allowed classification as positive (≥50% PSA reduction after pelvic radiation or positive biopsy) or negative (<50% PSA reduction after pelvic radiation; spontaneous PSA normalization) for LR, yielding 13 patients with standard DCE (11 LR+) and 12 with GRASP (10 LR+). Standard DCE had voxel size 3.0 × 1.9 × 1.9 mm and temporal resolution 5.5 s. GRASP had voxel size 1.0 × 1.1 × 1.1 cm and was retrospectively reconstructed at 2.3 s resolution. Two radiologists evaluated DCE sequences for image quality measures (1-5 scale) and the presence of LR.

RESULTS

GRASP achieved higher scores than standard DCE from both readers (p < 0.001-0.136) for anatomic clarity (R1: 4.4 ± 0.8 vs. 2.8 ± 0.67 R2: 4.8 ± 0.5 vs. 3.2 ± 0.6), sharpness (3.6 ± 0.9 vs. 2.5 ± 0.7; 4.6 ± 0.5 vs. 2.6 ± 0.5), confidence in interpretation (3.8 ± 0.8 vs. 3.1 ± 0.9; 3.8 ± 1.0 vs. 3.1 ± 1.2), and conspicuity of detected lesions (4.7 ± 0.5 vs. 3.8 ± 1.1; 4.5 ± 0.5 vs. 3.8 ± 1.0). For detecting LR, GRASP also achieved higher sensitivity (70% vs. 36%; 80% vs. 45%), specificity (R1 and R2: 100% vs. 50%), and accuracy (75% vs. 38%; 83% vs. 46%) for both readers.

CONCLUSION

Although requiring larger studies, high spatiotemporal resolution GRASP achieved substantially better image quality and diagnostic performance than standard DCE for detecting LR in patients with elevated PSA after prostatectomy.