Prostate cancer generally refers to adenocarcinoma of the prostate, which accounts for more than 98% of all prostate cancers. Less common prostatic malignancies include neuroendocrine tumors, squamous tumors, sarcomas, and transitional cell carcinomas. The only established risk factors for prostate cancer are age, race/ethinicity, and family history of prostate cancer.
Benign tissues in the peripheral zone show hyperintense signals in T2 weighted imaging, whereas malignant changes show hypointense signals, of which the reason could be the cellular density as well as the malfunction of the gland when the malignant change had occurred
Amol april prostate cancer imaging
Dr. Amol Gulhane
CARE HOSPITAL , HYD
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 ducts
25% of glandular tissue in young adults
Only 1-5% of prostate cancer from this region (likely because of
Wolffian duct embryologic origin)
Peripheral zone (PZ)
Mesodermal in origin
Majority of prostatic glandular tissue
Origin of up to 70% of prostate adenocarcinoma
Transitional zone (TZ)
Surrounds the prostatic urethra proximal to the veru (aka preprostatic
Endodermal in origin
In young men, accounts for only 5-10% of prostatic glandular tissue.
Only ~20% of prostate cancer arise from TZ
Gives rise to BPH
"Lobes" of the prostate
Enlargement of periuthral tissue in the TZ results in hyperplasia of "lateral
ZONAL ANATOMY OF
PROSTATEMC 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
•The prostate is supplied by branches from the
inferior vesical, middle rectal and internal
•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
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
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
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
The inner transition zone is separated from the peripheral
zone by the usually hypoechoic surgical capsule
The peripheral zone has a uniform, homogeneous
is slightly more echogenic than the transition zone.
The margin of the prostate forms a clear interface
with the periprostatic fat except posterolaterally,
where vessels enter the prostate and make the margin
indistinct, an appearance that can mimic tumor
through 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
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 is
composed 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
making cancer diagnosis difficult
C, Heterogeneous nature of hyperplasia in the transition zone; U, urethra.
(black arrow) and hypoechoic (*) areas are present. This inhomogeneity makes
cancer detection difficult. D, Sagittal view shows pitfall in
transrectal ultrasound (TRUS) imaging of BPH. If the field of view is not deep
enough (arrows), prominent median lobe enlargement
may 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 and
inferior vesical artery.
With color Doppler ultrasound, particularly using the
power mode, the prostate appears mildly to moderately
The capsular and urethral arteries are easily
seen, and branches to the inner gland and peripheral
zone may be prominent, often in a spokelike radial
pattern with the periurethral vessels as the axle
A dense cluster of vessels is often seen capping the
base of the prostate, and care must be taken not to
mistake 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 of
benign ectatic glands (arrows). C, Axial view shows extensive echogenic material,
both calcifications and corpora amylacea (arrows), along the surgical capsule and
D, Doppler examination of same patient shows the extensive Doppler noise
Benign ductal ectasia is seen in older men who develop
atrophy and dilation of peripheral prostatic ducts. These
are visible as single or grouped, radially oriented, 1 to
2–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 area
that 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 of
inflammation (*). 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.
An issue for TRUS and biopsy is that many of these men
elevated but often fluctuating PSA, even in excess
of 10 nanograms per milliliter (ng/mL) and the often multiple
inflammatory areas can mimic cancer at the
Biopsy may be needed to exclude cancer. The
free/total PSA ratio with inflammatory conditions tends
to 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 every
case and yield cancer at biopsy exceeding about 50%.
The 4 to 10–ng/mL window was problematic because
about 35% to 44% of men in this range have cancer.85,86
The remainder have benign causes for increased PSA
(e.g., BPH) and often undergo unnecessary biopsy (low
Production of PSA by benign prostate tissue (normal and
hyperplastic) is generally less than production by cancer.
If there is an excess PSA level above that predicted from
gland volume measured by TRUS, the patient has an
increased risk of cancer.
PSA density (PSAd) is defined
as 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 group
to those with PSAd in excess of 0.12 to 0.15 will detect
about 80% of those with cancer and avoid some biopsies.
Over time, PSA levels in men with
cancer usually rise
more rapidly than in men with BPH.
The classic appearance is that of a hypoechoic
nodule in the peripheral zone that cannot be
to benign causes typically located in the peripheral
and abutting the capsule
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
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, Typical
hypoechoic 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
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
large abnormal area of hypervascularity involving not only the small peripheral
Staging of extensive prostate cancer. TRUS is about as accurate
as CT and MRI for determining the
presence of extracapsular extension. A, Stage T3A cancer (T) has
extended outside the prostate at the neurovascular bundle
how difficult it is to differentiate tumor extension from the normal
irregularity caused by the neurovascular bundle. B, Stage T3C
view) 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
Sagittal image of the prostate
showing a hypoechoic area (white
arrow). This area was a focus of
showing an enhancing prostate
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
A well-defined fat plane exists between the
prostate and the obturator internus and is
Denonvilliers’ fascia, which acts as a physical
barrier to the
spread 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 neurovascular
The seminal vesicles are perched posterior and superolateral
atop the prostate gland. Superior soft tissue characterization
makes fl uid-sensitive MRI sequences the modality
of choice when evaluating the seminal vesicles, which are
Imaging in Prostate
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
Normal prostate has homogenous low signal
Zonal anatomy is best demonstrated on
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
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
To stage the extent of prostate cancer once the
diagnosis is established
To identify the presence of recurrent disease
Persistent raised PSA with repeated negative
MRI is not used in the primary diagnosis of prostate
cancer. This is usually established following biopsy at
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
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
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
Most prostate cancers can be visualized as low-
signal-intensity areas within the high-signal-
intensity normal tissue background of the
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.
TIWI : Tumor is isointense relative to gland
T2WI : Tumor appears as a region of low signal
intensity within normal high signal peripheral
Detection of extra capsular extension:
1. Asymmetry into neurovascular bundle
2. Obliteration of recto-prostatic angle
3. Irregular bulging or breech of prostate
MRI FINDINGS CONTD…
Diffusion Weighted Imaging :
Restricted diffusion with reduced ADC value.
: 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
Dynamic contrast enhanced MRI :
Early, rapid, and intense enhancement with quick
washout of contrast material
: Increased tumor neovascularsation and
thus increased micro vascular density as compared to
SPECTROSCOPY – NORMAL SPECTRAL
• 3D proton MR spectroscopic metabolic mapping of the
entire gland is possible with a resolution of 0.24 ml per
• Proton MR spectroscopy displays concentrations of citrate,
creatine, and choline metabolites found in the prostate gland
• 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
NORMAL METABOLITE OF PROSTATE
Citrate : Produced by normal epithelial cells
Normal Peak at 2.6 ppm
Choline : Precursor of phospholipids cell
Normal Peak at 3.2 ppm
Creatine : Involved in cellular energy
Normal peak at 3 ppm
SPECTROSCOPYAt 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
MR SPECTROSCOPY OF
Classic spectral signature of prostate cancer
consists of increased choline and decreased citrate
Ratio of (Choline + creatine)/ Citrate is usually
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
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.
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
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
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
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
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
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
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,
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 points
to 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
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
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
Cancer prostate at the peripheral zone with
high Choline peak and a low Citrate peak are
Peripheral prostate cancer in the right middle gland,
producing a capsular bulging (arrow) with high choline
Any pelvic lymph node with a maximum short-
axis diameter exceeding 10 mm or any
obturator or internal iliac lymph node
exceeding 8 mm in diameter is considered
Secondary findings that increase the suspicion
of a metastatic lymph node are loss of a central
fatty hilum and loss of the normal oval or
The 10-mm size criterion for abnormal lymph
nodes on CT has also
been validated for MRI; in addition, 8-mm
rounded lymph nodes are thought to be
of central necrosis is a predictive feature of metastatic
An advanced technique, dynamic contrast enhanced
MRI, attempts to image contrast opacification of
lymph nodes over time.
It has been suggested that the altered internal environment
of metastatic lymph nodes changes several parameters of
contrast flow dynamics
An emerging MRI technique that has shown promise
in the evaluation of nodal metastatic disease is
Injected ferumoxtran-10, an ultrasmall
iron oxide nanoparticle coated with dextran,
is actively phagocytosed by macrophages and causes
change that results in a drop in T2 and T2*
signal. These iron-containing macrophages circulate
populate the lymphatic system.
In benign lymph nodes, these macrophages are
deposited homogeneously; therefore,
signal dropout is due to the presence of ferrous
Lymph nodes with internal metastatic
deposits prevent homogeneous distribution or
exclude migrating macrophages, which results in lack
contrast agent and the retention of either partial or
T2 or T2* signal
Lymphotropic nanoparticle MR image demonstrating a benign lymph node. A,
Precontrast axial T2*-weighted image shows a
hyperintense right external iliac lymph node (arrow). B, The lymph node (arrow)
loses signal on the postcontrast T2*-weighted image, consistent
with no malignancy. This was confi rmed on biopsy.
Lymphotropic nanoparticle MR image demonstrating a malignant lymph
node from metastatic prostate cancer. A, Precontrast axial
T2*-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
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
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
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 children
leiomyosarcoma : most common in adults
malignant fibrous histiocytoma
phyllodes tumour (also known as cystosarcoma phyllodes of
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
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