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Advances in MR Imaging of PROSTATE CANCER Demetri Papadatos, MD, FRCPC Abdominal Imaging Radiologist Director, Abdominal Imaging Fellowship Director, Percutaneous.

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Presentation on theme: "Advances in MR Imaging of PROSTATE CANCER Demetri Papadatos, MD, FRCPC Abdominal Imaging Radiologist Director, Abdominal Imaging Fellowship Director, Percutaneous."— Presentation transcript:

1 Advances in MR Imaging of PROSTATE CANCER Demetri Papadatos, MD, FRCPC Abdominal Imaging Radiologist Director, Abdominal Imaging Fellowship Director, Percutaneous Radiofrequency Ablation The Ottawa Hospital

2 PROSTATE CANCER Most common malignancy of men in US Most common malignancy of men in US after skin cancer At autopsy, prostate cancer is found in At autopsy, prostate cancer is found in 30% of men at age 50 30% of men at age 50 almost 90% at age 90 almost 90% at age 90 About one in six men will be diagnosed with About one in six men will be diagnosed with prostate cancer during lifetime prostate cancer during lifetime However, only 1 / 34 will die of the disease However, only 1 / 34 will die of the disease

3 PROSTATE CANCER Many cancers are indolent, Many cancers are indolent, show no signs of clinical growth Despite the long latent period, Despite the long latent period, second commonest cause of cancer death in American men over age 55

4 ETIOLOGY - RISK FACTORS All men are at a risk of developing prostate cancer. All men are at a risk of developing prostate cancer. Age : Greatest risk factor Age : Greatest risk factor risk increasing significantly after 50 yrs risk increasing significantly after 50 yrs Family history: Men with affected father or brother at increased risk Family history: Men with affected father or brother at increased risk ACA Recommendation to start screening 10 yrs earlier ACA Recommendation to start screening 10 yrs earlier compare to general population compare to general population Genetic Factors – abnormal genes in 10 % Genetic Factors – abnormal genes in 10 % but genetic testing is not available yet but genetic testing is not available yet Race: Race: more frequent and aggressive in African American men more frequent and aggressive in African American men Environmental and dietary factors Environmental and dietary factors

5 HISTOPATHOLOGICAL TYPES More than 95% of prostatic malignancies are adenocarcinomas More than 95% of prostatic malignancies are adenocarcinomas Rarely, a squamous or transitional cell neoplasm Rarely, a squamous or transitional cell neoplasm Very rarely sarcoma Very rarely sarcoma

6 SCREENING Routine Screening is offered Routine Screening is offered Men > 50 yrs Men > 50 yrs With a life expectancy of at least 10 yrs With a life expectancy of at least 10 yrs Screening consists of : Screening consists of : Digital rectal examination Digital rectal examination Serum PSA levels Serum PSA levels

7 PSA (Prostatic Specific Antigen) Secreted into blood stream by the prostate gland Secreted into blood stream by the prostate gland It’s routine use for screening has lead an exponential rise in prostate cancers, which are being detected much earlier It’s routine use for screening has lead an exponential rise in prostate cancers, which are being detected much earlier Elevated PSA = non specific Elevated PSA = non specific Also seen in benign prostatic hypertrophy (BPH) Also seen in benign prostatic hypertrophy (BPH) and prostatitis (benign conditions) and prostatitis (benign conditions)

8 If PSA elevated Repeat PSA level a few weeks later Repeat PSA level a few weeks later when probable occult prostatitis has resolved Calculate PSA Density (PSA/gland volume) Calculate PSA Density (PSA/gland volume) increases PSA specificity transrectal ultrasound (TRUS) = gland volume + ? Nodules Free PSA increases PSA specificity Free PSA increases PSA specificity Low in CA Low in CA Elevated in benign prostatic hypertrophy (BPH) Elevated in benign prostatic hypertrophy (BPH) If < 25 % of PSA is free – worrisome for cancer If < 25 % of PSA is free – worrisome for cancer

9 DIAGNOSIS Diagnosis of prostate carcinoma is usually made Diagnosis of prostate carcinoma is usually made by TRUS-guided core biopsy. However, can have +ve/rising PSA but –ve biopsies However, can have +ve/rising PSA but –ve biopsies Dilemma Dilemma Do these patients have prostate cancer ??? Do these patients have prostate cancer ??? If so, why are the biopsies negative ??? If so, why are the biopsies negative ???

10 Transrectal Ultrasound (TRUS) and Biopsy (Bx) TRUS can assess gland volume (PSAD) TRUS can assess gland volume (PSAD) and detect nodules However, nodules may or may not represent cancer However, nodules may or may not represent cancer Therefore, perform multiple biopsies in attempt to find the suspected cancer Therefore, perform multiple biopsies in attempt to find the suspected cancer TRUS is used to guide needle placement for biopsies TRUS is used to guide needle placement for biopsies

11 TRUS Bx Systematic approach needed during biopsy session Systematic approach needed during biopsy session in order to maximize the yield Number and location of biopsies varies Number and location of biopsies varies Trend is to increase the number of biopsies obtained Trend is to increase the number of biopsies obtained Some cancers are located in nodules seen on TRUS Some cancers are located in nodules seen on TRUS However, more aggressive cancer may be located elsewhere and not visible on TRUS However, more aggressive cancer may be located elsewhere and not visible on TRUS Malignant prostatic nodules tend to look hypoechoic (dark) Malignant prostatic nodules tend to look hypoechoic (dark) and demostrate increased vascularity

12 EXTENDED BIOPSY PROTOCOLS EXTENDED BIOPSY PROTOCOLS Traditionally, a six biopsy protocol was used Traditionally, a six biopsy protocol was used Insufficient, tumours being missed and undergraded Insufficient, tumours being missed and undergraded In particular, midline and apicolateral PZ tumours were missed In particular, midline and apicolateral PZ tumours were missed 8 -10 biopsies improve diagnostic yield by 20–30% over traditional number of biopsies 8 -10 biopsies improve diagnostic yield by 20–30% over traditional number of biopsies Some centers recommend 24 biopsies (12 per side) Some centers recommend 24 biopsies (12 per side) to get +ve diagnosis to accurately grade the tumor

13 PATHOLOGY Gleason GRADE and Gleason Score Gleason Grade  1=Low …….. 5=High Gleason Grade  1=Low …….. 5=High

14 GLEASON SCORE A grade is assigned to the 2 largest foci of cancer A grade is assigned to the 2 largest foci of cancer These 2 grades are added together to yield the These 2 grades are added together to yield the Gleason score (eg. Grade 3 + Grade 4 = Score of 7) Gleason Score varies between 2 and 10 Gleason Score varies between 2 and 10 The higher the Gleason score – more aggressive tumor The higher the Gleason score – more aggressive tumor NB: Score of 7 (3+4 vs 4+3) NB: Score of 7 (3+4 vs 4+3)

15 GLEASON SCORE 2-6 = Low Risk 7 = Intermediate risk 8-10 = High risk

16 My prostate biopsy was positive, now what ? Surgery only proven curative treatment Surgery only proven curative treatment Only tumor confined to prostate is curable Only tumor confined to prostate is curable Surgery = HIGH morbidity/complications urinary incontinence + sexual impotence Surgery = HIGH morbidity/complications urinary incontinence + sexual impotence Need reliable staging tool to predict who will benefit from surgery Need reliable staging tool to predict who will benefit from surgery Before the advent of accurate staging with imaging, nomograms were developed Before the advent of accurate staging with imaging, nomograms were developed

17 CLINICAL NOMOGRAMS Originally designed to help predict the STAGE Originally designed to help predict the STAGE (as determined after surgery) and best course of treatment. (as determined after surgery) and best course of treatment. "Partin tables" "Partin tables" originally developed by 2 urologists originally developed by 2 urologists (Alan W. Partin and Patrick C. Walsh) based on accumulated data from hundreds of patients based on accumulated data from hundreds of patients treated for prostate cancer Most recent version of the Partin Tables, released in 2001 Most recent version of the Partin Tables, released in 2001 based on data from 5000 patients based on data from 5000 patients underwent radical prostatectomy at Johns Hopkins underwent radical prostatectomy at Johns Hopkins Can be used to determine pre test probabability of unresectable disease and decide if surgery is worth the potential complications Can be used to determine pre test probabability of unresectable disease and decide if surgery is worth the potential complications

18 ROLE OF MRI MR can detect cancer but is not recommended as an initial screening tool (PSA, DRE, TRUS Bx) MR can detect cancer but is not recommended as an initial screening tool (PSA, DRE, TRUS Bx) However  ? +ve PSA but –ve biopsy However  ? +ve PSA but –ve biopsy Does this patient have cancer ??? Does this patient have cancer ??? MR helps target repeat biopsy to suspicious areas MR helps target repeat biopsy to suspicious areas Local Staging (to determine best treatment) Local Staging (to determine best treatment)

19 WHO NEEDS MRI STAGING Most patients with prostate CA have indolent cancer Most patients with prostate CA have indolent cancer Will unlikely need any form of treatment during their lives as cancer will never manifest clinically High (+/- intermediate) risk groups High (+/- intermediate) risk groups ( ie significant chance of tumor progression)

20 WHO NEEDS MRI STAGING Staging MR would be cost effective if performed ONLY in the subgroup of patients with Palpable tumor Palpable tumor PSA > 10 PSA > 10 At least 50 % positive cores for malignancy At least 50 % positive cores for malignancy High Gleason grade and score High Gleason grade and score

21 IMAGING THE PROSTATE GLAND Currently imaging at 1.5 Tesla scanner is recommended Currently imaging at 1.5 Tesla scanner is recommended Endorectal /Surface Coil MRI combination is best for anatomic detail Endorectal /Surface Coil MRI combination is best for anatomic detail High SNR High SNR High spatial resolution of 0.5 mm High spatial resolution of 0.5 mm 5 MR techniques will be discussed today 5 MR techniques will be discussed today T2 Weighted Imaging T2 Weighted Imaging Dynamic contrast enhanced MRI (DCE-MRI) Dynamic contrast enhanced MRI (DCE-MRI) MR Spectroscopic Imaging (MRSI) MR Spectroscopic Imaging (MRSI) Diffusion weighted Imaging (DWI) Diffusion weighted Imaging (DWI) Lymphotropic Nanoparticle-enhanced MRI (Ferumoxtran-10) Lymphotropic Nanoparticle-enhanced MRI (Ferumoxtran-10)

22 NORMAL ANATOMY

23 ANATOMY OF THE GLAND Glandular (acinar) and nonglandular elements I - Glandular prostate 1- Outer components Central zone (CZ) Peripheral zones (PZ) 2- Inner components Periuretheral glands Transitinal zone (TZ) (BPH) II - Nonglandular portions Prostatic urethra Prostatic urethra Anterior fibromuscular band Anterior fibromuscular band

24 ABNORMAL GLAND

25 DISTRIBUTION OF PROSTATE CANCER Tumor location: Tumor location: 70 % in Peripheral Zone, PZ 70 % in Peripheral Zone, PZ 20 % in Transition Zone, TZ 20 % in Transition Zone, TZ 10 % in Central Zone, CZ 10 % in Central Zone, CZ Central gland most difficult to localize cancer Central gland most difficult to localize cancer because of overlapping signal intensity because of overlapping signal intensity with normal gland / hypertrophy

26 LOCAL STAGING - IMPORTANCE Accurate tumor staging is essential to determine appropriate treatment (ie is curative surgery an option ?) Accurate tumor staging is essential to determine appropriate treatment (ie is curative surgery an option ?) Extracapsular Extension (ECE) Seminal Vesicle Invasion (SVI) Bladder/Rectal Invasion Lymph Node Metastases Only carcinomas confined within the prostate gland, are potentially curable by radical prostatectomy Only carcinomas confined within the prostate gland, are potentially curable by radical prostatectomy Staging usually classified using TNM classification Staging usually classified using TNM classification

27 TNM CLASSIFICATION Primary tumor (T) TX: Primary tumor cannot be assessed T0: No evidence of primary tumor T1: Clinically inapparent tumor not palpable nor visible by imaging T1a: Tumor incidental histologic finding in <5% of tissue resected T1b: Tumor incidental histologic finding in >5% of tissue resected T1c: Tumor identified by needle biopsy (eg, because of elevated PSA) T2: Tumor confined within prostate T2a: Tumor involves < 50% of 1 lobe T2b: Tumor involves > 50% of 1 lobe T2c: Tumor involves both lobes T3: Tumor extends through the prostate capsule T3a: Extracapsular extension (unilateral or bilateral) ECE T3b: Tumor invades seminal vesicle(s) SVI T4: Tumor is fixed or invades adjacent structures other than seminal vesicles: bladder neck, external sphincter, rectum, levator muscles, and/or pelvic wall

28 TNM CLASSIFICATION Regional lymph nodes (N) Regional lymph nodes are the nodes of the true pelvis Distant lymph nodes are outside the true pelvis NX: Regional lymph nodes were not assessed NX: Regional lymph nodes were not assessed N0: No regional lymph node metastasis N0: No regional lymph node metastasis N1: Single regional lymph node (inside the pelvis) < 2 cm N1: Single regional lymph node (inside the pelvis) < 2 cm N2: One or more regional lymph nodes, largest > 2 cm but 2 cm but < 5 cm N3: One or more regional lymph nodes, largest > 5 cm N3: One or more regional lymph nodes, largest > 5 cm Distant metastasis (M) MX: Distant metastasis cannot be assessed (not evaluated by any modality) MX: Distant metastasis cannot be assessed (not evaluated by any modality) M0: No distant metastasis M0: No distant metastasis M1: Distant metastasis M1: Distant metastasis M1a: Non-Regional lymph node(s) M1a: Non-Regional lymph node(s) M1b: Bone(s) M1b: Bone(s) M1c: Other site(s) with or without bone disease M1c: Other site(s) with or without bone disease

29 STAGING OBJECTIVES To confirm organ-confined disease To confirm organ-confined disease radical surgical prostatectomy could be offered without adjuvant radiation therapy. If disease is largely organ-confined with small volume periprostatic or seminal vesicle spread, radical radiotherapy can still be offered If disease is largely organ-confined with small volume periprostatic or seminal vesicle spread, radical radiotherapy can still be offered with / without pelvic nodal irradiation or with / without pelvic nodal irradiation or with / without adjuvant hormonal therapy with / without adjuvant hormonal therapy To confirm clinically suspected apical tumor or extent of LN metastases which will affect radiotherapy margins. To confirm clinically suspected apical tumor or extent of LN metastases which will affect radiotherapy margins.

30 TIMING FOR MRI MRI should be delayed at least 4-8 weeks after biopsy MRI should be delayed at least 4-8 weeks after biopsy Post biopsy hemorrhage may hamper tumor detection in Post biopsy hemorrhage may hamper tumor detection in the gland the gland May result in under or overestimation of tumor presence May result in under or overestimation of tumor presence and local extent and local extent MR “exclusion sign”: cancers are resistant to the MR “exclusion sign”: cancers are resistant to the development of post biopsy hemorrhage development of post biopsy hemorrhage

31 LOCAL STAGING T STAGING

32 LOCAL STAGING Tumor extent Tumor extent Extra capsular extension Extra capsular extension Seminal vesicle invasion Seminal vesicle invasion Volume of tumor Volume of tumor Aggressiveness Aggressiveness

33 ORGAN CONFINED DISEASE Primary tumor – TNM Stage of T2 or less Primary tumor – TNM Stage of T2 or less Suitable for radical surgery Suitable for radical surgery Nerve sparing radical surgery if neurovascular bundles are clear Nerve sparing radical surgery if neurovascular bundles are clear Clinical estimation of the organ confined disease is Clinical estimation of the organ confined disease is based on clinical nomograms which takes into account based on clinical nomograms which takes into account PSA PSA DRE DRE Gleason score Gleason score MR imaging has been shown to have an incremental value additive to clinical nomograms MR imaging has been shown to have an incremental value additive to clinical nomograms

34 MRI SIGNS OF UNRESECTABLE DISEASE ( TNM Stage > T2 ) Extra capsular extension - ECE Extra capsular extension - ECE Invasion of periprostatic fat Invasion of periprostatic fat Invasion of neuromuscular bundle Invasion of neuromuscular bundle Seminal Vesicle Invasion - (SVI) Seminal Vesicle Invasion - (SVI) Invasion of adjacent organs (Bladder, Rectum) Invasion of adjacent organs (Bladder, Rectum) Metastases to pelvic lymph nodes Metastases to pelvic lymph nodes

35 EXTRACAPSULAR EXTENSION - ECE

36 ECE Most imp to diagnose Most imp to diagnose Endorectal coil imaging with T1 & T2W seq. only Endorectal coil imaging with T1 & T2W seq. only OR OR Endorectal imaging with spectroscopy Endorectal imaging with spectroscopy

37 MRI SIGNS OF ECE Assessed on AXIAL & CORONAL images Contour deformity with step off or angulated margin Contour deformity with step off or angulated margin Irregular bulge or capsule retraction Irregular bulge or capsule retraction Capsular breach & direct tumor extension Capsular breach & direct tumor extension Obliteration of rectoprostatic angle Obliteration of rectoprostatic angle Asymmetry of neurovascular bundles Asymmetry of neurovascular bundles

38 SEMINAL VESICLE INVASION

39 MRI SIGNS OF SEMINAL VESICLE INVASION (SVI) Combined AXIAL, SAGITAL & CORONAL images facilitates detection of SV invasion Contiguous low SI from base of gland in SV Contiguous low SI from base of gland in SV Extension of soft tissue along ejaculatory ducts Extension of soft tissue along ejaculatory ducts Asymmetric decrease in SI of SV Asymmetric decrease in SI of SV Decreased conspicuity of SV wall on T2WI Decreased conspicuity of SV wall on T2WI

40 BLADDER & RECTAL INVASION

41 T2WI – SENITIVITY AND SPECIFICITY Varies widely for cancer detection Varies widely for cancer detection Without endorectal coil Without endorectal coil Sensitivity : 45 % Sensitivity : 45 % Specificity : 73 % Specificity : 73 % With Endorectal coil With Endorectal coil Sensitivity : 77 - 91 % Sensitivity : 77 - 91 % Specificity : 27 - 61 % Specificity : 27 - 61 %

42 How do we increase specificity ? Keep Endorectal Coil MRI T2 imaging Keep Endorectal Coil MRI T2 imaging (high sensitivity) and add: Contrast-enhanced MRI (CE-MRI) Contrast-enhanced MRI (CE-MRI) MR Spectroscopic Imaging (MRSI) MR Spectroscopic Imaging (MRSI) Diffusion-weighted MRI (DWI) Diffusion-weighted MRI (DWI)

43 DYNAMIC CONTRAST ENHANCED MRI – DCE MRI

44 WHY TUMORS ENHANCE DIFFERENTLY THAN NORMAL TISSUES Cancers results in tumor angiogenesis Cancers results in tumor angiogenesis Increased no. of vessels Increased no. of vessels Increased permeability of vessels Increased permeability of vessels Increased interstitial tissue space Increased interstitial tissue space

45 DCE MRI Fast GRE seq. can scan entire vol. of gland in few seconds Fast GRE seq. can scan entire vol. of gland in few seconds Various perfusion parameters are electronically extracted according to time seq. Various perfusion parameters are electronically extracted according to time seq. Relative peak enhancement is most reliable perfusion parameter for cancer detection Relative peak enhancement is most reliable perfusion parameter for cancer detection Improves specificity compared to T2W scans Improves specificity compared to T2W scans Tumors can be detected with higher accuracy but it does not improve staging Tumors can be detected with higher accuracy but it does not improve staging

46 DCE MRI - IMPROVEMENT IN DETECTION RATES Peripheral zone cancers Peripheral zone cancers Sensitivity : 96 % Sensitivity : 96 % Specificity: 97 % Specificity: 97 % Compared to 75 % and 53 % respectively on T2WI Compared to 75 % and 53 % respectively on T2WI Not tested in multi institutional trials Not tested in multi institutional trials Suffers from lack of uniformly accepted analytic method Suffers from lack of uniformly accepted analytic method Still of unproven benefit as per ACR guidelines Still of unproven benefit as per ACR guidelines

47 DCE MRI – Analysis of data 3 methods of analysis 3 methods of analysis Qualitative  Easier Qualitative  Easier Look at curves Look at curves Semi-Qualitative  Average Semi-Qualitative  Average Parameters from curves Parameters from curves Quantitative  Complicated Quantitative  Complicated Mathematical Modelling Mathematical Modelling

48 MR SPECTROSCOPY - MRS

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

50 SPECTROSCOPY – SPECTRAL ANALYSIS Healthy peripheral-zone voxels typically have Healthy peripheral-zone voxels typically have diagnostic levels of Cit with (Cho + Cr)/Cit ratios diagnostic levels of Cit with (Cho + Cr)/Cit ratios less than 0.5 less than 0.5 Because of the proximity of the choline and Because of the proximity of the choline and creatine peaks at 1.5-T MR unit two peaks cannot be separated creatine peaks at 1.5-T MR unit two peaks cannot be separated

51 TUMOR VOLUME

52 There is an association between primary tumor volume and local extent of disease, progression, and survival There is an association between primary tumor volume and local extent of disease, progression, and survival A review of a large number of prostate cancers in surgical and autopsy specimens showed A review of a large number of prostate cancers in surgical and autopsy specimens showed Capsular penetration Capsular penetration Seminal vesicle invasion and Seminal vesicle invasion and Lymph node metastases Lymph node metastases usually found only with tumors larger than 1.4 cc

53 TUMOR VOLUME Another study - ECE in 18 % with vol. < 3 cc Another study - ECE in 18 % with vol. < 3 cc 79% with volume > 3 cc 79% with volume > 3 cc Tumor volume – significant predictor of ECE Tumor volume – significant predictor of ECE Bx, TRUS and T2-MRI disappointing in volume estimation Bx, TRUS and T2-MRI disappointing in volume estimation MRS provides more accurate volume estimation MRS provides more accurate volume estimation

54 ROLE OF SPECTROSCOPY IN ESTIMATING TUMOR VOLUME Relative tumor volume is determined on MRS Relative tumor volume is determined on MRS ( counting the voxels containing abnormal spectra ) ( counting the voxels containing abnormal spectra ) Improves Dx of ECE for both experienced and less experienced reader Improves Dx of ECE for both experienced and less experienced reader Decrease inter observer variability – further studies required to assure improvement in the performance of truly inexperienced reader Decrease inter observer variability – further studies required to assure improvement in the performance of truly inexperienced reader

55 MR SPECTROSCOPY - MRS MR SPECTROSCOPY - MRS Technically demanding and time consuming Technically demanding and time consuming Improvement in diagnostic accuracy and staging have been reported but not proved in multi institutional trials Improvement in diagnostic accuracy and staging have been reported but not proved in multi institutional trials ACR clinical trial is currently underway ACR clinical trial is currently underway Currently cannot be considered as routine diagnostic tool Currently cannot be considered as routine diagnostic tool

56 Diffusion-weighted Imaging (DWI) Diffusion is the process of thermally induced random molecular displacement – Brownian motion Diffusion is the process of thermally induced random molecular displacement – Brownian motion Diffusion properties of tissues are related Diffusion properties of tissues are related Amount of tissue water Amount of tissue water Tissue permeability Tissue permeability Cancer tends to have restricted diffusion due to Cancer tends to have restricted diffusion due to High cell densities High cell densities Abundant intracellular membranes Abundant intracellular membranes

57 DWI ADVANTAGES ADVANTAGES Short acquisition time Short acquisition time High contrast resolution between tumor and normal tissue High contrast resolution between tumor and normal tissue No need for endorectal Coil No need for endorectal Coil DISADVANTAGES DISADVANTAGES Poor spatial resolution Poor spatial resolution Potential risk of image distortion by post biopsy Hg Potential risk of image distortion by post biopsy Hg

58 LOCAL STAGING N STAGING

59 ABNORMAL NODES Early metastases can occur in small nodes Early metastases can occur in small nodes Size and shape of nodes inaccurate for staging Size and shape of nodes inaccurate for staging ABNORMAL NODES ABNORMAL NODES Rounded configuration Rounded configuration Short axis > 10 mm if oval, > 8 mm if round Short axis > 10 mm if oval, > 8 mm if round T1 OR T2 SI – not helpful T1 OR T2 SI – not helpful Enhancement suggestive of metastatic lymph node Enhancement suggestive of metastatic lymph node

60 SHORTCOMINGS- NODAL STAGING Normal sized nodes - contain cancer as micro metastases Normal sized nodes - contain cancer as micro metastases Enlarged nodes may be reactive Enlarged nodes may be reactive

61 DETECTION OF ABNORMAL LYMPH NODES Neither CT nor MRI is accurate as laparoscopic nodal dissection Neither CT nor MRI is accurate as laparoscopic nodal dissection Initial step prior to radical prostatectomy remains nodal dissection Initial step prior to radical prostatectomy remains nodal dissection MR is at least as accurate as CT in nodal staging MR is at least as accurate as CT in nodal staging If good chance the prostate cancer has already spread If good chance the prostate cancer has already spread to the lymph nodes laparoscopic lymph node dissection to the lymph nodes laparoscopic lymph node dissection is a minimally invasive procedure to begin with is a minimally invasive procedure to begin with

62 Lymphotropic Nanoparticles ULTRASMALL SUPER PARAMAGNETIC MR contrast agents taken up by macrophages ULTRASMALL SUPER PARAMAGNETIC MR contrast agents taken up by macrophages Distributes to LNs throughout the body Distributes to LNs throughout the body Injected intravenously and imaged 24 hrs later Injected intravenously and imaged 24 hrs later +++ susceptibility effect on T2* MR images +++ susceptibility effect on T2* MR images Cannot enter tumor (no macrophages) Cannot enter tumor (no macrophages) Can differentiate normal/reactive lymph nodes from malignant ones Can differentiate normal/reactive lymph nodes from malignant ones Iron based contrast agents not approved by FDA Iron based contrast agents not approved by FDA(Ferumoxtran-10)

63 Future trends 3T MRI 3T MRI Increased SNR Increased SNR Increased spatial resolution Increased spatial resolution ? Assessment of microscopic disease ? Assessment of microscopic disease ? Need for Endorectoil Coil ? Need for Endorectoil Coil Standardized technique for CE-MRI with availability of vendor software Standardized technique for CE-MRI with availability of vendor software Approval of Approval of Lymphotropic Nanoparticles for accurate nodal staging

64 Thanks to: Arifa Sadaf Radiology, Radiographics and AJR Researchers who develop Prostate MR

65 Thank You


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