Changes in prostatic thickness and the location of ejaculatory ducts in autopsy prostates

Prostatic peripheral zone thickness: what is normal on magnetic resonance imaging?

PURPOSE

To report the precision of a technique of measuring the PZ thickness on T2-weighted MRI and report normal parameters in patients with normal-sized prostates. We also wanted to establish the mean and second standard deviations (2SD) above and below the mean as criteria for abnormally narrow or expanded PZ thickness.

METHODS

Of the initial 1566 consecutive cohort referred for evaluation for carcinoma based on elevated PSA (prostate specific antibody) or DRE (digital rectal examination), 132 separate subjects with normal-sized prostates were selected for this study. Mean age was 58.2 years (15-82). Median serum PSA was 6.2 ng/mL (range 0.3-145). Most were asymptomatic for lower urinary tract symptoms (LUTS). Inclusion criteria in this study required technically adequate T2-weighted MRI and total prostatic volume (TPV) ≤ 25 cc. Exclusion criteria included post-prostatic surgical and radiation patients, patients having had medical management or minimally invasive therapy for BPH, those being treated for prostatitis. Patients with suspected tumor expanding or obscuring measurement boundaries were also not considered. Transition zone (TZ) and peripheral zone (PZ) volumes were determined using the prolate ellipsoid model. Posterolateral measurement of the PZ was obtained at the axial level of maximal transverse diameter of the prostate on a line drawn from the outer boundary of the TZ to the inner boundary of the external prostatic capsule (EPC). The data were normally distributed. Therefore, it was analyzed using the 2-sided student t-test and Pearson product correlation statistic.

RESULTS

Mean pooled (composite) measurement for the posterolateral PZ (PLPZ) was 10 mm (CI 9.5-10.5 mm) with SD of 2.87 mm. Means were statistically the same for the 2 observers (p = 0.75). Pearson correlation between the two observers was 0.63.

CONCLUSIONS

In a prostate ≤ 25 cc volume , the posterolateral PZ should be no thicker than 15.8 mm and averages 10.0 mm when measured in the maximal axial plane on MRI. These norms were independent of age or use of endorectal coil. The technique measurement demonstrated clinically useful precision.

Morphology of ejaculatory ducts: A systematic review

The morphology of human ejaculatory ducts has not been well established. The objective of this study was to describe macroscopic and microscopic anatomy of ejaculatory ducts. We conducted a systematic review using MEDLINE, Scopus, PubMed, and Cochrane databases. Search terms were: "ejaculatory ducts," "seminal colliculus," "prostatic utricle," "anatomy," "histology," "radiology," and "embryology." We only included studies assessing adult (>18 years) humans published before November 1, 2019. We excluded studies describing pathological ducts and case reports. Independent authors extracted data using predefined criteria. Fourteen studies were included in the qualitative synthesis. Usually, the ejaculatory ducts entered the prostate by piercing the central part of its base. Most studies identified an anteromedial curve of the ducts at the outset within the prostate, their subsequent course being a straight path towards the seminal colliculus, their terminal parts diverging immediately before joining the prostatic urethra. However, the morphology of the terminal part of the ducts was inconsistent. The mean length of the ducts ranged from 1.4 to 2.2 cm. In conclusion, the luminal diameter gradually decreased as the ducts traveled towards the seminal colliculus. Ejaculatory ducts angulate anteromedially at their onset within the prostate and travel straight towards the seminal colliculus. Their terminal parts diverge immediately before joining the prostatic urethra. However, the reported dimensions of the ducts differ among studies.

Transurethral balloon laser thermotherapy: effects of a directionally shielded balloon in canine prostates

BACKGROUND

Transurethral balloon laser thermotherapy (TUBAL-T) improves objective, but not subjective, symptoms of benign prostatic hyperplasia (BPH). We studied whether or not an Nd:YAG laser beam with a shielded balloon could successfully irradiate the prostate during TUBAL-T in selective manner, to improve the subjective symptoms.

METHODS

TUBAL-T was performed on canine prostates using the balloon with a laser probe, which was shielded anteriorly at 90 degrees (from the center of the balloon) and posteriorly at 90 degrees.

RESULTS

At 20 watts laser power, the relative power density in the bilateral non-shielded areas was 17.4 and 17.8, and in the shielded area it was 1.0. Observation by thermography revealed that the temperature after laser radiation in a non-shielded area of a fish cake phantom was higher than in a shielded area. Following transurethral thermotherapy using a shielded balloon in dogs, a cavity was formed bilaterally around the urethra, and the tissues at the anteroposterior sides and the urethra were preserved.

CONCLUSIONS

TUBAL-T, which has been performed in clinical cases of benign prostatic hyperplasia, might be useful in selective irradiation of adenoma if a shielded balloon is used.