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

Area of Science:

• Radiology
• Medical Imaging
• Prostate Cancer Diagnostics

Background:

• Accurate measurement of prostate zonal anatomy is crucial for diagnosing prostate conditions.
• T2-weighted MRI is a key imaging modality for evaluating the prostate.
• Establishing normative data for prostate measurements is essential for identifying deviations.

Purpose of the Study:

• To precisely measure peripheral zone (PZ) thickness using T2-weighted MRI in normal-sized prostates.
• To define normal PZ thickness parameters, including mean and standard deviations.
• To establish criteria for identifying abnormally narrow or expanded PZ thickness.

Main Methods:

• 132 subjects with normal-sized prostates (≤25 cc) were selected from a larger cohort.
• T2-weighted MRI was used to measure the posterolateral PZ (PLPZ) thickness.
• Data were analyzed for precision and correlation between observers.

Main Results:

• The mean PLPZ thickness was 10 mm (95% CI 9.5-10.5 mm) with a standard deviation of 2.87 mm.
• Inter-observer agreement for PZ thickness measurement was good (Pearson correlation = 0.63).
• Measurements were consistent across different observers (p=0.75).

Conclusions:

• Normal PZ thickness in prostates ≤25 cc averages 10 mm, with an upper limit of 15.8 mm.
• These MRI-derived norms are independent of patient age or the use of an endorectal coil.
• The measurement technique demonstrated clinically useful precision for evaluating PZ thickness.