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Explore the anatomy and imaging manifestation of the male genital organs, particularly the prostate gland. Learn about normal appearances on various MRI sequences and the characteristics of prostate cancer on imaging studies.
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Genitourinary Imaging-----Prostate Xiaotao Cai
Applied Anatomy and Normal Imaging Manifestation • Male genital organs Various external and internal male organs concerned with reproduction.
rectum seminal vesicle urethra Male genital organs Schematic drawing
Male genital organs Urinary bladder Urinary bladder,neck Urinary bladder,trigone Urethra, prostatic Urethra, membranous Urethra, penile Urethra, male Urethra, bulbous Radiograph, contrast mediam,micturating urethrocystogram, AP projection
Normal CT Manifestation 1 prostate gland：size older 5 4 5 Cm younger 3 2 3 Cm 2seminal vesicle
Male genital organs transection bladder seminal vesicle
Male genital organsprostate prostate
MR Imaging Appearance of Normal Prostate Anatomy • On T1WI, the normal prostate gland demonstrates homogeneous intermediate-to-low signal intensity. • As with computed tomography (CT), T1WI has insufficient soft-tissue contrast resolution for visualizing the intraprostatic anatomy or abnormality. • The zonal anatomy of the prostate gland is best depicted on high-resolution T2WI
Normal Prostate Anatomy • T2WI： • Transitional Zone • Central Zone • Peripheral Zone • Anterior Fibromuscular Stroma • Prostatic Capsule
Normal Prostate T2WI T1WI T2FS T2WI coronal plane
Male genital organs seminal vesicle
Normal prostate zonal anatomy • A 60-year-old man • T2WI at the level of the seminal vesicles • at the base of the prostate • B = urinary bladder • C = central zone
Normal prostate zonal anatomy • A 60-year-old man • T2WI at the level of the mid-gland • FS = anterior fibromuscular stroma • P = peripheral zone • T = transition zone
Normal prostate zonal anatomy • A 60-year-old man • T2WI at the level of the apex • at the level of the membranous urethra • U = urethra
Normal prostate zonal anatomy Normal prostate zonal anatomy in a 60-year-old man T2WI corona, midsagittal, and parasagittal MR images The letters in g correspond to the anatomic levels used for images a-f The vertical line in g indicates the membranous urethral length. B = urinary bladder, C = central zone, P = peripheral zone, SV = seminal vesicles, U = urethra.
Male genital organs MRI, T1-weighted, axial section. (serial sections, cranial to caudal)
Male genital organs MRI, T1-weighted, axial section. (serial sections, cranial to caudal)
contrast-enhanced MR • On contrast-enhanced MR images, the peripheral zone enhances more than the transition or central zone. • The contrast resolution is similar to that seen on T2WI
prostate cancer outline Incidence: doubles with each decade after age 50; 180,400 new cases + 31,900 deaths in USA (2000); 2nd most common malignancy in males (after lung cancer); in 35% of men >45 years of age (autopsies) ; One out of 11 males will develop prostate cancer!
Racial factors:8.7% in White males, 9.4% in Black males; less common in Asians • Risk factors: advancing age, cadmium exposure, animal fat intake; first-degree relative • Histology: adenocarcinoma (common);
Staging of Prostate Cancer American Urological Association System (modified Jewitt-Whitmore Staging System)
Clinical categories: • Latent carcinoma = usually discovered at autopsy of a patient without signs or symptoms referable to the prostate ; • Incidental carcinoma = discovered in of specimens obtained during transurethral resection for clinically benign prostatic hyperplasia ; • Occult carcinoma = found at biopsy of metastatically involved bone lesion / lymph node in a patient without symptoms of prostatic disease ; • Occult carcinoma = found at biopsy of metastatically involved bone lesion / lymph node in a patient without symptoms of prostatic disease
elevated Prostate-Specific Antigen (PSA) • is measured by a monoclonal radioimmunoassay • Cancers of <1 mL usually do not • 16% of normal men have PSA >4 ng/mL • 19% of prostate cancers have normal • Benign conditions with PSA elevation: benign prostatic hypertrophy, prostatitis, prostatic intraepithelial neoplasia
MR Appearance of Prostate Cancer • low-signal abnormality within the normally high-signal glandular tissue of the peripheral zone on T2WI • tumor isointense relative to surrounding gland on T1WI • capsule optimally depicted on T1WI due to demarcation by high signal-intensity periprostatic fat • direct tumor extension beyond prostate
MR Appearance of Prostate Cancer • decreased signal intensity in periprostatic fat adjacent to capsule near the tumor on T1WI + T2WI • capsular thickening • irregular focal bulge in contour of capsule near the tumor • flattening / obliteration of rectoprostatic angle
MR Appearance of Prostate Cancer • asymmetry of neurovascular bundle • low-signal lesion on T2WI within seminal vesicles that are normally of high-signal intensity
Biopsy-proved adenocarcinoma • A 71-year-old man with a PSA level of 5.65 ng/mL • axial T2WI and coronal T2WI show that the dominant tumor (T) within the left peripheral zone extends from the apex to the base. Obliteration of the left rectoprostatic angle is indicative of extracapsular extension. • Findings at surgery and histopathologic examination helped confirm a large tumor with extracapsular extension
Prostate cancer • T2-weighted axial MR images show an asymmetric bulge and spiculated margin • obliteration of the rectoprostatic angle
Prostate cancer • T2-weighted axial MR images show breach of the capsule with direct tumor extension and envelopment of the neurovascular bundle, and asymmetry of the neurovascular bundles
prostate cancer • sagittal plane T1WI pos-contrast
Biopsy-proved adenocarcinoma • A 58-year-old man with a PSA level of 50.0 ng/mL • T2WI axial and sagittal images reveal a large tumor (T) that invades the entire prostate gland and demonstrate gross extracapsular extension and direct invasion of the urinary bladder and seminal vesicles
Biopsy-proved adenocarcinoma • A 62-year-old man with a PSA level of 15.1 ng/mL • T2WI axial and sagittal images demonstrate diffuse tumor invasion of the prostate gland with direct tumor (T) extension to the wall of the urinary bladder and the anterior rectal wall. The multiple low-signal-intensity lesions in the pubic bones are consistent with bone metastases
Postbiopsy hemorrhage axial T1WI and T2WI and coronal T2WI demonstrate extensive bilateral postbiopsy hemorrhage in the peripheral zones. The transition zone in the left lobe demonstrates high signal intensity on the T1WI and low signal intensity on the T2WI
DDx: post-biopsy hemorrhage (low signal on T2WI + high signal on T1WI) • Prognosis :increase in tumor volume increases probability of capsular penetration, metastasis, histologic dedifferentiation • Mortality :2.6% for White males, 4.5% for Black males; 34,000 deaths/1992
Screening recommendation (American Urological Association, American Cancer Society): • PSA level measurements + digital rectal exam annually • Rx:(1) Watchful waiting (2) Radical prostatectomy for disease confined to capsule + life expectancy >15 years (3) Radiation therapy for (a) disease confined to capsule, life expectancy <15 years (b) disease outside capsule, no spread (4) Hormonal therapy (orchiectomy, diethylstilbestrol, leuprolide acetate) for widely metastatic disease (5) Cryosurgery (6) Chemotherapy
benign prostatic hyperplasia (BPH) • The prostrate is a small male gland the size of a walnut that is found at the base of the bladder which surrounds the neck of the bladder and the urinary outlet known as the urethra. • Benign prostatic hyperplasia (BPH) which is also known as benign prostatic hypertrophy is the natural enlargement of the prostrate gland which typically happens to a man after the age of 40, it is non-malignant. • One in three men over 50 years of age will experience the symptoms associated with benign prostatic hyperplasia (BPH), the condition increases with age.
benign prostatic hyperplasia (BPH) • The typical symptoms of a man who has Benign prostatic hyperplasia (BPH) are, a need to urinate more especially at night, difficulty with starting to urinate, a weak urinary stream which causes dribbling and starting and stopping whilst in mid flow and having a feeling of not emptying the bladder properly. • If the prostrate gland enlarges too much and urinations become too difficult or impossible than further complications may arise with kidney damage and urinary track infections.
benign prostatic hyperplasia (BPH) • A change in diet in general does not help with Benign prostatic hyperplasia (BPH) but a change in lifestyle does, men who are more physically active tend to have less Benign prostatic hyperplasia (BPH) symptoms, walking is especially good. The best supplements to take for benign prostatic hyperplasia (BPH) are extract of saw palmetto berries.
