Anatomical and metabolic assessment of prostate using a 3‐Tesla MR scanner with a custom‐made external transceive coil: Healthy volunteer study

Abstract

Purpose:To examine the possibility of using a 3 Tesla (T) magnetic resonance (MR) scanner with a custom-made external coil to obtain ductal details of the prostate, highquality spectra, and metabolite mapping corresponding to prostate zonal anatomy in healthy volunteers. Materials and Methods:MRI and two-dimensional (2D) chemical shift imaging (CSI) were performed in 16 healthy volunteers using a 3T scanner with a custom-made external transmit-receive (transceive) coil. Visualization of the prostatic duct-like structure was analyzed on T2-weighted (T2W) images. The resolution of the metabolite peaks and the distribution of metabolites in CSI were also assessed. Results:In the axial plane, 3-mm-thick images were better than 4-mm-thick images with the same voxel volume for assessing duct-like structures and prostatic urethra. Differentiation between inner and outer citrate (Cit) peaks was frequently observed (29 out of 30). The mean peak area ratio of choline (Cho) plus creatine (Cr) over Cit in the peripheral zone (PZ) was significantly lower than in the transition zone (TZ) (P ϭ 0.014). Conclusion:3T MR examinations of the prostate using an external coil allow information to be collected about the details of duct-like structures, the high-quality spectra of Cit, and the zone-specific distribution of metabolites.

Performance of external and internal coil configurations for prostate investigations at 7 T

“…Beyond roERC and roESA coils currently in use clinically, there are several examples where local transmit coils have been developed for prostate imaging. Transceiver external surface arrays (trESAs) have been previously presented for use at field strengths of 3 T (15, 16), 4 T (17), and 7 T (18). Other coil configurations have included a trESA in combination with a roERC at 4 T (19) and transceiver ERCs (trERC) at 7 T (20–22).…”

“…These challenges are a result of the quadratic relationship between B 0 and RF power as well as the increasingly complex B fields. With respect to performance, it was sufficient at 3 and 4 T to predetermine B shimming solutions determined from the geometric design of trESA RF coils (15–17). However, this one size fits all approach becomes far less optimal at 7 T, where the RF wavelength becomes as short as ∼12 cm in the body, so that B fields vary much more rapidly and are increasingly affected by body geometry and coil position.…”

MR spectroscopy of the human prostate using surface coil at 3 T: Metabolite ratios, age‐dependent effects, and diagnostic possibilities

“…The 3 T prostate spectra of healthy volunteers have been demonstrated in previous studies (15–18). However, the quality and quantity of the spectra did not enable the evaluation of age‐related metabolite changes or estimation, other than (Cho+PA+Cr)/Cit spectral intensity ratio.…”

“…Prostate spectroscopy using surface coils is easier, less expensive, and can be widely used in a standard clinical environment. MRSI using surface coils has been demonstrated in previous studies (8, 9, 15, 16). The drawback of using a surface coil compared to the ER coil, however, is the associated larger voxel that is needed to compensate for a lowered sensitivity.…”

“…Only a few spectroscopy examinations at 3 T have been performed on healthy volunteers (15–18). To our knowledge, only one research group evaluated normal values of (choline [Cho] + polyamines [PA] + creatine [Cr] to citrate [Cit]) spectral intensity ratio for peripheral zone and central gland tissue (8).…”