Sonography of the prostate: In vitro correlation of sonographic and anatomic findings in normal glands

The quality of images obtained with sonography of specimens in a water bath is comparable with that of images obtained transrectally because, in both cases, the beam transverses little or no intervening tissue before reaching the prostate gland. Because our specimens were obtained at autopsy in men without known prostatic disease, no in vivo sonograms were available for comparison. The anatomy of the central portion of the normal prostate deserves emphasis. This part of the gland stands out sonographically because it is hypoechoic relative to the peripheral (glandular) zone. The central portion, composed of fibromuscular stroma, is most apparent sonographically in levels below and above the seminal colliculus; the central portion should not be confused with the central zone described by McNeal and coworkers. They referred to a subset of the glandular prostate related to the ejaculatory ducts, which sonographically blends with the peripheral (glandular) zone. Recognition of the central zone histologically is facilitated by the use of the high-power objective and special stains. Sonographic/anatomic correlation by using whole-mount histologic preparations of normal prostate glands in planes of interest to the sonographer has immediate clinical applicability in performing transrectal sonography because all disease processes must be considered within the framework of normal anatomic structure.