Carr-Purcell-Meiboom-Gill imaging of prostate cancer: quantitative T2 values for cancer discrimination

Abstract

Quantitative, apparent T2 values of suspected prostate cancer and healthy peripheral zone tissue in men with prostate cancer were measured using a Carr-Purcell-Meiboom-Gill (CPMG) imaging sequence in order to assess the cancer discrimination potential of tissue T2 values. The CPMG imaging sequence was used to image the prostates of 18 men with biopsy proven prostate cancer. Whole gland coverage with nominal voxel volumes of 0.54 × 1.1 × 4 mm3 was obtained in 10.7 minutes, resulting in data sets suitable for generating high quality images with variable T2-weighting and for evaluating quantitative T2 values on a pixel-by-pixel basis. Region-of-interest analysis of suspected healthy peripheral zone tissue and suspected cancer, identified on the basis of both T1- and T2-weighted signal intensities and available histopathology reports, yielded significantly (p < 0.0001) longer apparent T2 values in suspected healthy tissue (193 ± 49 ms) vs. suspected cancer (100 ± 26 ms), suggesting potential utility of this method as a tissue specific discrimination index for prostate cancer. We conclude that CPMG imaging of the prostate can be performed in reasonable scan times and can provide advantages over T2-weighted fast spin echo imaging alone, including quantitative T2 values for cancer discrimination as well as proton density maps without the point spread function degradation associated with short effective echo time fast spin echo (FSE) sequences.

Characterization of prostate cancer using T2 mapping at 3T: A multi-scanner study

“…First, in agreement with several other studies performed at 1.5 T [17][18][19][20] or at 3 T [10], we found the T2 value to be significantly lower in PZ cancers than in normal PZ. However, to be useful in daily practice, the T2 measurement must discriminate malignant from benign tissue in the subgroup of areas appearing suspicious on mp-MRI.…”

Three‐dimensional balanced steady state free precession imaging of the prostate: Flip angle dependency of the signal based on a two component T2‐decay model

“…Roebuck et al (18) noted a slight curvature when plotting signal versus TE in the range 28-180 ms on a semilogarithmic plot. This curvature appears to be a striking feature when the range of TE extends to 800 ms (11).…”

“…This difference disappeared when the fit of the monoexponential decay was limited to the early echoes. The previously published prostate T2 relaxation times based on monoexponential fits range from approximately 60 ms for tumor and the central gland to more than 300 ms for the peripheral zone (13)(14)(15)(16)(17)(18)(19). There is a large scatter in the estimates, presumably due to the variation in acquisition techniques.…”

New efforts to quantitative T2-mapping imaging

“…Generally, Carr-Purcell-Meiboom-Gill (CPMG) Pulse Sequence is used during collecting the multi-echo spin echo signals [11,12]. It uses a 90 degree RF pulse along the X axis followed by a train of evenly spaced 180 degree RF pulses along the Y axis of the rotating frame to acquire them.…”