Amol april prostate cancer imaging

Imaging of prostate cancerDr. Amol Gulhane CARE HOSPITAL , HYD

INTRODUCTION

2nd most common malignant tumor in male.

95% are adenocarcinoma

Higher incidence in African Americans, incidence raising in India

Age : 6th to 7th decade.

Symptoms: Dysuria, hematuria, urgency+/‐ frequency of micturition, bone pain

Diagnosis: Combination of DRE & PSA. 

Confirmation of diagnosis-Transrectal biopsy under Ultrasound guidance

Zones of Prostate: Central zone (CZ)

Cone shaped region that surround the ejaculatory ducts (extends from bladder base to the veru) Likely stems from Wolffian ducts25% of glandular tissue in young adultsOnly 1-5% of prostate cancer from this region (likely because of Wolffian duct embryologic origin)

Peripheral zone (PZ)Posteriolateral prostateMesodermal in originMajority of prostatic glandular tissueOrigin of up to 70% of prostate adenocarcinoma

Transitional zone (TZ)Surrounds the prostatic urethra proximal to the veru (aka preprostatic urethra)Endodermal in originIn young men, accounts for only 5-10% of prostatic glandular tissue.Only ~20% of prostate cancer arise from TZGives rise to BPH

"Lobes" of the prostateEnlargement of periuthral tissue in the TZ results in hyperplasia of "lateral lobes“ In some men, hyperplasia of periurethral glands of the TZ at the bladder neck produces a "median lobe" -- tissue mass that can ball-valve into the outlet .

ZONAL ANATOMY OF PROSTATE

MC NEAL 1968

In the axial plane, the prostate is divided into four zones: (a)the anterior fibromuscular stroma, which contains no glandular tissue; (b) the transition zone surrounding the urethra, which contains 5% of the glandular tissue; (c)the central zone, which contains 20% of the glandular tissue; and (d)the outer peripheral zone, which contains 70%–80% of the glandular tissue.

•The prostate is supplied by branches from the inferior vesical, middle rectal and internal pedendal arteries.

•Rich plexus of vein are present to the side and base of prostate which communicates freely with internal pudendal and vertebral venous plexus, these ate valveless veins.

TRUS is widely available, well tolerated by patients, and relatively inexpensive.

It is optimally performed with high-frequency TRUS probes and the whole prostate is imaged in the transverse and sagittal plane. The prostate volume can be approximated by multiplying the height, depth, and width of the prostate with 0.52 (prolate ellipsoid formula).

With TRUS, the prostate is shown to be divided into an isoechoic peripheral zone and a more heterogeneous central gland, comprising the transition zone.

Calcifications (corpora amylacea) are common at the boundary between the peripheral zone and the central gland. The seminal vesicles can be visualized as convoluted hypoechoic cystic structures

Axial sonograms of prostate. A, Transverse image above base shows the seminal vesicles (SV) and vas deferens(V); B, bladder. B, Axial scan at midgland level. Note the normal hypoechoic muscular internal urethral sphincter (horizontal arrows) and the ejaculatory ducts (vertical arrow). C, Axial scan at lower third of prostate shows hypoechoic urethra (U). Most of the visible gland at this level is peripheral zone. Note the irregular outline at the posterolateral aspects (arrows), resulting from the entrance of the neurovascular bundles. D, Axial scan just below apex of prostate shows cross section of distal urethra (U). Pelvic sling muscles are visible (arrows).

The inner transition zone is separated from the peripheralzone by the usually hypoechoic surgical capsule

The peripheral zone has a uniform, homogeneous texture andis slightly more echogenic than the transition zone.

The margin of the prostate forms a clear interfacewith the periprostatic fat except posterolaterally,where vessels enter the prostate and make the marginindistinct, an appearance that can mimic tumor extensionthrough the capsule.

Sagittal views of prostate. A, Midsagittal view shows internal urethral sphincter (white arrows), which contains the echogenic collapsed urethra (*). The ejaculatory ducts (E) course from the vas deferens (V) to the verumontanum (oblique arrow).B, Midsagittal view at base shows the vas deferens (V) and adjacent seminal vesicles (S) as they enter the prostate. C, Parasagittalview shows the lateral prostate, which is homogeneous and isoechoic and composed almost totally of peripheral zone tissue D, Parasagittal view above the prostate shows the normal seminal vesicles (SV) and vas deferens (V) in cross section above theprostate (P).

Benign prostatic hyperplasia (BPH). A, Axial view shows the greatly enlarged, slightly hypoechoic transition zone (TZ), which compresses the more echogenic peripheral zone (PZ). Their interface is the surgical capsule (*). The region inside the surgical capsule (transition zone) is also called the “inner gland” and the region outside the surgical capsule, the “outer gland,” which iscomposed of peripheral zone plus central zone. (Peripheral zone is the “eggcup” holding the “egg” of the central gland.)B, Benign degenerative

cysts in the transition zone (arrows). These have no clinical significance. The transition zone can become acoustically very inhomogeneous,making cancer diagnosis difficult

C, Heterogeneous nature of hyperplasia in the transition zone; U, urethra. Both hyperechoic(black arrow) and hypoechoic (*) areas are present. This inhomogeneity makes cancer detection difficult. D, Sagittal view shows pitfall intransrectal ultrasound (TRUS) imaging of BPH. If the field of view is not deep enough (arrows), prominent median lobe enlargementmay be cut off and may escape detection.

E, Transvesical midsagittal scan shows obvious massive enlargement of the median lobe (ML)protruding into the bladder; P, prostate. Evaluation for symptoms of prostatism is better done transvesically than transrectally with TRUS.F, Axial view of typical transurethral resection of prostate (TURP) surgical defect (*).

The prostate is supplied by the prostaticovesical arteries,which arise from the internal iliac arteries on each side.These vessels then gives rise to the prostatic artery andinferior vesical artery.

With color Doppler ultrasound, particularly using thepower mode, the prostate appears mildly to moderatelyvascular.

The capsular and urethral arteries are easilyseen, and branches to the inner gland and peripheralzone may be prominent, often in a spokelike radialpattern with the periurethral vessels as the axle

A dense cluster of vessels is often seen capping thebase of the prostate, and care must be taken not tomistake these for tumor vascularity.

Normal anatomic variants. A, Axial view with benign glandular ectasia (arrows) seen as a peripheral hypoechoic area containing multiple radially oriented tubes. This hypoechoic appearance should not be mistaken for cancer. B, Parasagittal view ofbenign ectatic glands (arrows). C, Axial view shows extensive echogenic material, both calcifications and corpora amylacea (arrows), along the surgical capsule and peripheral zoneD, Doppler examination of same patient shows the extensive Doppler noise artifact caused by the calcifications. Virtually all the visible color is artifactual

Normal VariantsBenign ductal ectasia is seen in older men who developatrophy and dilation of peripheral prostatic ducts. Theseare visible as single or grouped, radially oriented, 1 to2–mm–diameter tubular structures in the peripheral zone,starting at the capsule and radiating toward the urethra.When clustered, dilated ducts can form a hypoechoic areathat could be mistaken as prostate cancer.

Prostatitis. Most men with prostatitis have a normal-appearing prostate that can be exceedingly tender if the condition is acute. A, Biopsy-proven nonacute inflammation. Multiple geographic hypoechoic areas on both sides (arrows) mimic tumor on TRUS and Doppler and are associated with PSA elevation. B, Power Doppler ultrasound demonstrates increased vascularity in areas ofinflammation (*). C, BCG noncaseating granulomatous prostatitis as a mass lesion (arrow) in a man whose bladder cancer had been treated with bacille Calmette-Guérin (BCG) instillation. This mimics tumor, but the diagnosis can be suspected from the history. D, Granulomatous prostatitis mimics cancer and here appears as a tumor extending beyond the capsule and invading the rectal wall (arrow);I, inflammatory mass.

An issue for TRUS and biopsy is that many of these men have chronicallyelevated but often fluctuating PSA, even in excessof 10 nanograms per milliliter (ng/mL) and the often multipleinflammatory areas can mimic cancer at theultrasound.

Biopsy may be needed to exclude cancer. Thefree/total PSA ratio with inflammatory conditions tendsto be higher than seen with cancer

PSA level of 4 mg/mL or less(and more currently, <2.5 ng/mL) was believed to be“negative” and not needing biopsy; values over 10 ng/mL are sufficiently high to recommend biopsy in everycase and yield cancer at biopsy exceeding about 50%.

The 4 to 10–ng/mL window was problematic becauseabout 35% to 44% of men in this range have cancer.85,86The remainder have benign causes for increased PSA(e.g., BPH) and often undergo unnecessary biopsy (lowspecificity).

PSA DensityProduction of PSA by benign prostate tissue (normal andhyperplastic) is generally less than production by cancer.

If there is an excess PSA level above that predicted fromgland volume measured by TRUS, the patient has anincreased risk of cancer.

PSA density (PSAd) is definedas PSA/volume (e.g., PSA 6.0 and gland volume 75 cc;PSAd = 6.0/75 = 0.08).

Restricting biopsy in the PSA 4 to 10–ng/mL groupto those with PSAd in excess of 0.12 to 0.15 will detectabout 80% of those with cancer and avoid some biopsies.

Over time, PSA levels in men with cancer usually risemore rapidly than in men with BPH. The

The classic appearance is that of a hypoechoicnodule in the peripheral zone that cannot be attributedto benign causes typically located in the peripheral zoneand abutting the capsule

Sonographic AppearanceGray-Scale Ultrasound

Axial and sagittal images of the prostate showing extensive hypoechoic areas. This patient had a prostate-specific antigen level of 17 ng/mL and digital rectal examination findings highly suggestive of cancer. Biopsy revealed granulomatous prostatitis.

Prostate cancer: typical appearances. A, Hypoechoic nodule in peripheral zone along the capsule which cannot be attributed to benign causes (arrow). B, Giant pathology section of A shows the homogeneous solid cellular mass of tumor tissue (arrow), which reflects sound poorly compared with the adjacent prostate, which has the multiple glandular interfaces. C, Typicalhypoechoic peripheral zone cancer nodule (T). Note also the well-circumscribed hypoechoic BPH nodule in the right transition zone (arrow). D, Giant section of C for correlation shows the homogeneous tumor mass (T). There is a second small lesion on the right side(thick arrow). Also note the right and left BPH nodules correlating with the TRUS image (arrows

Prostate cancer: less common appearances. A, Small hypoechoic lesion entirely inside the peripheral zone (arrow) proved to be cancer. Digital rectal examination (DRE) was negative but PSA slightly elevated. B, Power Doppler scan of A shows increased vascularity (arrow) in region of the nodule. C, Small “tip of the iceberg” lesion visible posteriorly in the right lobe (T).Cancer is filling virtually the entire right lobe (white and black arrows). Most of this tumor is isoechoic and thus not visible on gray-scale imaging. Remember that prostate cancer is typically multifocal and larger than the lesion seen at TRUS. D, Power Doppler scan showslarge abnormal area of hypervascularity involving not only the small peripheral hypoechoic lesion, but also most of the transition zone (arrows); PSA, 265 ng/mL; Gleason score, 7/10.

Staging of extensive prostate cancer. TRUS is about as accurate as CT and MRI for determining thepresence of extracapsular extension. A, Stage T3A cancer (T) has extended outside the prostate at the neurovascular bundle (arrows). Notehow difficult it is to differentiate tumor extension from the normal irregularity caused by the neurovascular bundle. B, Stage T3C (parasagittalview) cancer (T) extending (arrows) into the seminal vesicles (SV) above the prostate.

Transrectal ultrasonographic imaging of prostate carcinoma (prostate-specific antigen level = 1.8 ng/mL). Biopsy showed a Gleason score of 3 + 3. (A) Transverse image reveals a slightly more echogenic peripheral zone (pz) and the carcinoma nodule (n) as a more hypoechoic focus. cg = central gland. (B) Sagittal image reveals a hypoechoic nodule (arrow). sv = seminal vesicle.

Sagittal image of the prostate showing a hypoechoic area (white arrow). This area was a focus of cancer on biopsy findings

Contrast-enhanced ultrasound showing an enhancing prostate cancer.

Grayscale ultrasound showing a hypoechoic nodule in the left peripheral zone (arrow). There is interruption of the normal green band on elastography with a stiff area that corresponds to the nodule. Biopsy confirmed Gleason grade 7 prostate cancer.

A well-defined fat plane exists between theprostate and the obturator internus and is delineated byDenonvilliers’ fascia, which acts as a physical barrier to thespread of disease.

Important neurovascular structures lie within the pericapsular fat—both anterior to the apex, as the anterior periprostatic plexus, and posterolateral to it, as the neurovascularbundles.

The seminal vesicles are perched posterior and superolateralatop the prostate gland. Superior soft tissue characterizationmakes fl uid-sensitive MRI sequences the modalityof choice when evaluating the seminal vesicles, which areT2 hyperintense

Imaging in Prostate Carcinoma:

Plain radiographs of the pelvis cannot be used to demonstrate localized disease in the prostate, and they are generally only needed in the evaluation of metastatic disease.

Most skeletal metastases from prostate cancer (about 85%) are osteoblastic and are visible as an area of abnormal tracer activity on a radionuclide bone scan.

In case of doubt, targeted imaging with skeletal radiographs can help distinguish metastatic areas from degenerative disease.

CT scanning has little value in demonstrating intraprostatic pathology and in local staging.

However, it may be helpful in detecting metastatic disease, such as lymph node involvement or bone metastases.

Nodal staging is indicated in patients with a prostate-specific antigen (PSA) value of 20 ng/mL or higher, a clinical stage T2b or higher, and a Gleason score of 7 or higher.

CT or MRI scans depict lymph node enlargement and have similar accuracy for the evaluation of lymph node metastases. However, nodal staging relies on assessment of lymph node size, and neither CT scan nor MRI can demonstrate cancer within lymph nodes that are not enlarged.

NORMAL MRI APPEARANCE OF PROSTATE

Normal prostate has homogenous low signal on T1WI

Zonal anatomy is best demonstrated on T2WI

Comprise of low signal central zone and higher signal peripheral zone

TZ and CZ appears similar in SI and loosely termed the central gland

NORMAL T2 APPEARANCE OF PROSTATE

Midprostate level : Homogeneously bright peripheral zone (arrowheads) surrounding the central gland (white arrows). The central gland is composed of the transition zone and central zone, which cannot be resolved at imaging. Therefore, they are referred to jointly as the central gland. Note the neurovascular bundles at the 5-o’clock and 7-o’clock positions (black arrows).

At the base of bladder: The anterior fibromuscular stroma (arrow) consists of nonglandular tissue and appears dark. Note the symmetric homogeneous muscular stroma layer (arrowheads) in the posterior prostate base

At prostate apex : The homogeneous peripheral zone (arrowheads) surrounding the urethra (U). Note that the volume of the peripheral zone increases from the base to the apex.

MR IMAGING IN PROSTATE CAINDICATION –

To stage the extent of prostate cancer once the diagnosis is established

To identify the presence of recurrent disease following treatment

Persistent raised PSA with repeated negative TRUS biopsies.

MRI is not used in the primary diagnosis of prostate cancer. This is usually established following biopsy at TRUS

MR IMAGING PROTOCOL

MRI is usually performed on 1.5T or 3T MRI using endorectal and pelvic phase array coil.

Standard Sequences : 1. Axial T1WI of pelvis 2. Axial + Sagittal + Coronal T2WI 3. MR Spectroscopy of selected volume of

prostate Others, 4. Diffusion Weighted Imaging 5. Dynamic contrast enhanced MRI.

Morphologic MRI (T1- and T2-weighted imaging)

T1WI prostate appears homogeneous with medium signal intensity; neither the zonal anatomy nor intraprostatic pathology is displayed, but if the MRI is performed after biopsy, post biopsy hemorrhage can be identified as areas of high T1-signal intensity.

T2-weighted sequences exquisitely depict the prostatic zonal anatomy. The central gland usually consists of nodular areas of varying signal intensity, depending on the relative amount of hypointense stromal and hyperintense glandular elements.

The normal peripheral zone has high signal intensity (as it is mainly composed of numerous ductal and acinar elements with hyperintense secretions

Most prostate cancers can be visualized as low-signal-intensity areas within the high-signal-intensity normal tissue background of the peripheral zone.

Because about 70% of all prostate cancers occur within the peripheral zone,

morphologic T2-weighed imaging can thus depict the majority of all prostate cancers.

Reported sensitivities (22-85%) and specificities (50-99%) vary widely, the latter illustrating the fact that low-signal-intensity areas are by no means specific for prostate cancer, since benign conditions such as prostatitis, hemorrhage, hyperplastic nodules, or post-treatment (hormonal or irradiation) changes may equally show low signal intensity.

CONVENTIONAL MRI FINDINGSTIWI : Tumor is isointense relative to gland

T2WI : Tumor appears as a region of low signal intensity within normal high signal peripheral zone

Detection of extra capsular extension: 1. Asymmetry into neurovascular bundle 2. Obliteration of recto-prostatic angle 3. Irregular bulging or breech of prostate

capsule 4. Invasion of bladder / rectum / seminal vesicle.

MRI FINDINGS CONTD…

Diffusion Weighted Imaging :

Restricted diffusion with reduced ADC value.

Explanation: Increased cellularity of malignant lesions, with reduction of the extracellular space and restriction of the motion of a larger portion of water molecules to the intracellular space

Dynamic contrast enhanced MRI :

Early, rapid, and intense enhancement with quick washout of contrast material

Explanation: Increased tumor neovascularsation and thus increased micro vascular density as compared to normal prostate.

SPECTROSCOPY – NORMAL SPECTRAL ANALYSIS

• 3D proton MR spectroscopic metabolic mapping of the entire gland is possible with a resolution of 0.24 ml per voxel.

• Proton MR spectroscopy displays concentrations of citrate, creatine, and choline metabolites found in the prostate gland and cancer.

• Normal prostate tissue contains high levels of citrate -higher in the PZ than in the central gland.

• Prostatic cancer: higher cell membrane turnover, Higher levels of choline and increased citrate.

MR SPECTROSCOPY OF PROSTATE

NORMAL METABOLITE OF PROSTATE Citrate : Produced by normal epithelial cells of prostate

Normal Peak at 2.6 ppmCholine : Precursor of phospholipids cell membrane

Normal Peak at 3.2 ppmCreatine : Involved in cellular energy

Normal peak at 3 ppm

NORMAL MR SPECTROSCOPY At 1.5 T At 3 T

A.MR spectroscopic spectrum, obtained at 1.5 T shows a high citrate (Ci) peak (resonance at 2.6 ppm) and a low choline (Ch)peak (resonance at 3.2 ppm), characteristics of benign tissue. The choline and creatine (Cr)peaks are overlapping.

B.At 3 T : Good separation of the choline (Cho)and creatine (Cr)peaks at higher magnetic field strength. The spectrum is normal, with a high concentration of citrate (Ci)and low concentration of choline.

MR SPECTROSCOPY OF PROSTATE

Classic spectral signature of prostate cancer consists of increased choline and decreased citrate

Ratio of (Choline + creatine)/ Citrate is usually measured.

Normal range : 0.22 +/- 0.013, range upto 0.5.

Lower values for the Cho+cr /Cit ratio in the peripheral areas than in the central glands.

Choline / creatine to citrate ratios:

> 0.5 : suspicious

> 1 : very suspicious

> 2 : abnormal

Diffusion-weighted Imaging (DWI).

• Diffusion is the process of thermally induced random molecular displacement – Brownian motion

• Diffusion properties of tissues are related – Amount of tissue water – Tissue permeability

• Cancer tends to have restricted diffusion due to – High cell densities – Abundant intracellular membranes

Radionuclide bone scanning after the injection of a technetium-99m (99m Tc) tracer is the current standard for assessing potential bone metastases from prostate cancer in patients with a prostate-specific antigen (PSA) value above 20 ng/mL, a Gleason sum of 4+3 or higher, or in case of symptoms that might be attributable to potential bone metastasis.

Bone scans have a high sensitivity but low specificity for metastatic prostate cancer. In case of doubt (eg, degenerative vs metastatic disease), targeted imaging with plain films, CT scanning, or MRI may be necessary. With diffuse bone metastases, a "superscan" may be seen; this superscan demonstrates high uptake throughout the skeleton, with poor or absent renal excretion of the tracer.

Prostatic abscess - Axial T2W image (A) of the prostate shows a focus of hyperintense signal (arrow) in the left midzone of the peripheral gland. On the axial T1W image (B), the lesion is barely seen. An axial, contrast-enhanced, T1W image (C) shows that the lesion (arrow) has peripheral enhancement and central non enhancement. DWI (b value=800) (D) shows high signal in the lesion (arrow) due to restriction of diffusion. The corresponding ADC map (E) shows low signal (arrow)

Prostatic abscess - Axial T2W MRI of the prostate (A) shows high signal (arrow) in the central gland, in the left midzone. Axial T1W image (B) shows mixed signal intensity with peripheral hyperintensity (arrow). Axial, contrast-enhanced T1W image (C) shows a peripherally enhancing abscess (arrow). DWI (b=800) (D) shows restriction of diffusion (arrow) in the lesion. The corresponding ADC map (E) shows low signal (arrow).

TUMOR STAGE

T2 stage prostate cancer 2D T2W axial image on the left. 3D T2W axial image on the right. Arrows depict a focal area of low signal intensity within the normal high signal intensity peripheral zone consistent with T2 stage cancer.

T2 stage prostate cancer 2D T2W images on the left. 3D T2W images on the right. Arrows depict a focal area of low signal intensity within the normal high signal intensity peripheral zone consistent with T2 stage cancer.

T3a stage prostate cancer. upper image: 2D T2W axial image lower image: 3D T2W axial image Arrows depict extracapsular extension of a focus of low signal intensity on the left consistent with T3a prostate cancer

T3b prostate cancer Upper image: 2D T2W axial image Lower image: 3D T2W axial image Arrows depict focus of low signal intensity within the seminal vesicles consistent with T3b prostate cancer.

Imaging of the prostate with and without endorectal coil. (A) Transverse image of the prostate performed with phased-array coils without an endorectal coil reveals adequate differentiation of the central gland (cg), peripheral zone (pz), and the tumor nodule (n). However, visualization of the prostatic capsule near the tumor is poor (arrow). (B) Transverse image of the prostate with the endorectal coil shows the central gland (cg), peripheral zone (pz), and tumor nodule (n), with better visualization of the prostatic capsule near the tumor (arrow).

Typical appearance of prostate carcinoma on magnetic resonance imaging. Subsequent biopsy revealed a Gleason score of 4 + 4. (A) T1- weighted image shows homogeneous low signal of the prostate (p), with no discrimination of the central and peripheral gland. The tumor nodule is not seen because no tissue contrast is present between the tumor and peripheral zone. The neurovascular bundles (black arrows) are seen laterally. (B) T2-weighted image shows the lower-signal intensity tumor (n) compared to the curve from zone on either side. (C) Coronal image shows the tumor nodule (n) with the adjoining apical prostatic capsule shown (arrow). (D) Early-phase gadolinium chelate-enhanced sections from a fast 3-dimensional gradient echo sequence show rapid intense enhancement of the tumor nodule (n), manifested by brighter signal intensity in the rest of the prostate, with tumor extending laterally to greater extent than is apparent on the T2-weighted image.

Prostatic carcinoma on magnetic resonance imaging with diffusion-weighted imaging of a patient with a prostate-specific antigen level of 3.1 ng/mL. Subsequent biopsy revealed a Gleason score of 3 + 4 with extracapsular extension. (A) T2-weighted and rectal coil image reveals a tumor nodule (n) contrasted with a higher-signal intensity peripheral zone. The central gland (cg) is expanded by benign prostatis hyperplasia, which has a lower signal intensity. (B) Apparent diffusion coefficient (ADC) map of the prostate reveals that the tumor nodule (n) has a lower signal intensity than the peripheral zone or the central gland (cg). Low signal intensity indicates that the ADC is lower than that of water and the water diffusion within the tumor is restricted. The ADC map is calculated from a set of three images at the same level (not shown) and performed with three different magnitudes of strength of diffusion-encoding gradients. (C) Early-phase gadolinium chelate-enhanced slice from a fast 3-dimensional gradientecho sequence reveals rapid, intense enhancement of the tumor nodule (n). Portions of the central gland (cg) also reveal rapid enhancement.

Typical enhancement characteristics of a tumor on dynamic contrast-enhanced images in a patient with a prostate-specific antigen level of 15 ng/mL. Biopsy showed a Gleason score of 4 + 4. (A) Transverse T2-weighted image reveals a tumor nodule (n) involving both the central gland and the peripheral zone on the right side of the prostate. The arrow pointsto the capsular involvement on the right. (B) Early-phase gadolinium chelate-enhanced slice from a fast 3-dimensional gradient-echo sequence reveals a rapid, intense enhancement of the tumor nodule (n) on the right side of the prostate. (C) Late-phase enhanced T1-weighted image reveals the tumor nodule (n) with a lower signal intensity, indicating washout of the contrast compared with the rest of the prostate. Typically, a tumor demonstrates early enhancement and early washout (as shown in this case).

Axial T2 and DCE images show a 9 x 7 x 9 mm tumor abutting the capsule. A distinct capsule can still be seen, suggesting capsular infiltration without ECE.

T2-weighted imaging (left) of a man with extensive Gleason 3+4 tumor shows low signal thoughout the peripheral zone corresponding to tumor. Very high b-valued high-resolution DWI (right) image shows restricted diffusion in the same tumor compared to normal prostate.

Axial T2W–MRI, b | apparent diffusion coefficient map of diffusion-weighted MRI, and c | raw DCE–MRI demonstrate a 1 cm right apical mid-peripheral zone lesion (asterisk). d | Magnetic resonance spectroscopy shows an elevated choline.

Axial T2W–MRI, b | apparent diffusion coefficient map of DW–MRI, and c | raw DCE–MRI demonstrate a large 5 cm lesion, which affects almost the entire prostate (asterisk). d,e | The lesion has extra capsular extension.

Cancer prostate at the peripheral zone with high Choline peak and a low Citrate peak are evident.

Peripheral prostate cancer in the right middle gland, producing a capsular bulging (arrow) with high choline peak and low citrate.

Any pelvic lymph node with a maximum short-axis diameter exceeding 10 mm or anyobturator or internal iliac lymph node exceeding 8 mm in diameter is considered pathologic.Secondary findings that increase the suspicion of a metastatic lymph node are loss of a central fatty hilum and loss of the normal oval orround shape.

The 10-mm size criterion for abnormal lymph nodes on CT has alsobeen validated for MRI; in addition, 8-mm rounded lymph nodes are thought to be abnormal.

The presenceof central necrosis is a predictive feature of metastaticlymph nodes.

An advanced technique, dynamic contrast enhancedMRI, attempts to image contrast opacification oflymph nodes over time.

It has been suggested that the altered internal environmentof metastatic lymph nodes changes several parameters ofcontrast flow dynamics

An emerging MRI technique that has shown promisein the evaluation of nodal metastatic disease is lymphotropicnanoparticle–enhanced MRI.

Injected ferumoxtran-10, an ultrasmall superparamagneticiron oxide nanoparticle coated with dextran,is actively phagocytosed by macrophages and causes a susceptibilitychange that results in a drop in T2 and T2*signal. These iron-containing macrophages circulate andpopulate the lymphatic system.

In benign lymph nodes, these macrophages are deposited homogeneously; therefore,signal dropout is due to the presence of ferrous contrastagent

Lymph nodes with internal metastaticdeposits prevent homogeneous distribution or completelyexclude migrating macrophages, which results in lack ofcontrast agent and the retention of either partial or highintensityT2 or T2* signal

Lymphotropic nanoparticle MR image demonstrating a benign lymph node. A, Precontrast axial T2*-weighted image shows ahyperintense right external iliac lymph node (arrow). B, The lymph node (arrow) loses signal on the postcontrast T2*-weighted image, consistentwith no malignancy. This was confi rmed on biopsy.

Lymphotropic nanoparticle MR image demonstrating a malignant lymph node from metastatic prostate cancer. A, Precontrast axialT2*-weighted image shows a hyperintense left internal iliac lymph node (arrow). B, The node (arrow) retains signal on the postcontrast T2*-weighted image, consistent with malignancy. This was confi rmed on biopsy.

Focal (A) and multifocal (B) distribution of prostate carcinoma within the prostate gland (arrows). Scatter plots of the segmental 11C-choline maximal standardized uptake value reveal higher 11C-choline maximal standardized uptake values in most segments with prostate carcinoma compared with segments with benign histopathological lesions. From Reske SN, Blumstein NM, Neumaier B, et al. Imaging prostate cancer with 11C-choline PET/CT.

Pt with prostatectomy 10 years previously. External beam radiation 1 year previously for a rising PSA. The PSA continued to increase up to 6.9 ng/mL. The 3 dimensional Carbon-11 Acetate PET/CT images show a small metabolic lymph node in the left pelvis (yellow arrows). This would not have been diagnosed on CT alone based on its small size. Other areas of ‘red’ seen on the images are of normal Carbon Acetate in the intestines, kidneys, liver and spleen. No other lesions were seen. The left pelvis node was treated with IMRT and the PSA then decreased to 0.9 ng/mL, confirming involvement of the identified node.

Ptwith Gleason 7 prostate cancer and external beam radiation (EBRT) to the prostate 4 years previously. PSA nadir was 0.43ng/mL. Rising PSA to 3.9 ng/mL. The 3 dimensional Carbon-11 Acetate PET/CT images show a metabolic focus in the right side of the prostate gland (yellow arrows). No other lesions were seen. The prostate recurrence was confirmed by biopsy with subsequent Brachytherapy performed. The PSA decreased to 0.6 ng/mL after treatment.

Gentleman with Gleason 6 prostate cancer. Brachytherapy and external beam radiotherapy 12 years previously. PSA nadir was 0.16 ng/mL. Rising PSA to 2.17 ng/mL. The 3 dimensional Carbon-11 Acetate PET/CT images show a single small metabolic lymph node in the left upper pelvis (yellow arrows). As in Case example #1, this would not have been diagnosed on CT alone based on its small size. Bilateral pelvic lymph node dissection was performed with 13 nodes removed. The node identified on the C11-Acetate imaging study was confirmed to be involve with prostate cancer (Gleason 4+4=8) and all other removed nodes were negative/benign, confirming the solitary finding on the imaging study. The PSA decreased to 0.19 ng/mL after the lymph node surgery.

Prostatic sarcoma is an uncommon and heterogenous group of tumour arising from mesenchymal cells in and around the prostate. In children the most common tumour type is a prostatic rhabdomyosarcoma, which accounts for approximately a third of all prostatic sarcomas .

In adults leiomyosarcomas are most common, accounting for approximately a quarter of all cases . Many other sarcomas have been reported although in general they are rare. Overall prostatic sarcomas include:rhabdomyosarcoma : most common in childrenleiomyosarcoma : most common in adults sarcomatoid carcinomamalignant fibrous histiocytomaphyllodes tumour (also known as cystosarcoma phyllodes of the prostate)undifferentiated stromal sarcoma

Sarcoma of the Prostate.

Prostate sarcoma.

Sarcoma of the Prostate.

Sarcoma of the Prostate.

Two cases of primary prostatic B cell lymphoma.

Melanoma-of-the-prostate-with-metastases-to-lung.

Metastasis of a cecal adenocarcinoma to the prostate.

extensive blastic form metastatic prostate cancer but minimal symptoms of pain. There is diffuse blastic replacement of every lumbar vertebra with uniform and symmetrical involvement of the entire pelvis bilaterally and minimal, if any, distortion of the external architecture of the vertebral bodies with no evidence of codfish deformity or collapse. Paget's disease can have a similar appearance but with blastic prostate metastases, the spine rarely collapses and it is usually asymptomatic

Whole body bone scan of a prostate cancer patient with extensive osseous metastases involving multiple levels in the thoracic spine, lumbar spine and sacrum. There are multiple metastases in the rib cage, bilateral bony pelvis and both scapulae.

Thank You.