Why is the prostate cancer hardly visible on diffusion-weighted images (DWI) in this case?
This is due to androgen deprivation therapy (ADT).
Are there signs suggestive of seminal vesicle invasion (SVI)?
There is homogenous moderate hypointensity in T2w images along the ejaculatory ducts above the prostate and within the inferior portions of both seminal vesicles.
Findings:
Quality: no major artefacts
Prostate size: 41 x 35 x 35 mm (CC x AP x ML) ≈26 mL.
Haemorrhage: none
Peripheral zone (PZ): diffusely hypointense on T2 and ADC and hyperintense on b1400
Transition zone (TZ): diffusely hypointense, indistinct margins of the pseudocapsule, loss of zonal boundaries
Prostate margin: broad capsular contact
Neurovascular bundles: close proximity, probably involved
Seminal vesicles: diffuse hypointensity along the ejaculatory duct and inferior portions of both seminal vesicles
Lymph nodes: oval external iliac lymph nodes (up to 5 mm size, fatty hilum, smooth margins)
Pelvic bones: small lesion in the right femoral head very likely bone island, no definite signs of bony metastasis
Side note: bilateral ureteric stents with the tip in the bladder
Impression:
Shrunken prostate in a histologically proven prostate cancer with infiltration of both lobes on androgen deprivation therapy.
Signs of seminal vesicle invasion.
MRI putative stage: cT3bNxMx