Endorectal Coil Magnetic Resonance Imaging Research Articles

Endorectal MRI for risk classification of localized prostate cancer: Radiographic findings and influence on treatment decisions

PurposeTo report the results of endorectal coil magnetic resonance imaging (eMRI) in patients with localized prostate cancer, and how these images influenced radiotherapeutic management. Materials and methodsA total of 122 men with localized adenocarcinoma of the prostate referred to radiation oncology underwent 3-T eMRI between 2010 and 2014, to evaluate candidacy for active surveillance (n = 26) and brachytherapy as monotherapy (n = 47), or to further risk stratify intermediate-risk (n = 29) or high-risk (n = 20) men before external beam radiation therapy. By National Comprehensive Cancer Network classification, men had low-risk (28%), intermediate-risk (55%), or high-risk (17%) disease. Multiparametric MRI sequences included T2-weighted, diffusion-weighted imaging, and dynamic contrast-enhanced imaging. Radiographic extracapsular extension, seminal vesicle invasion (rSVI), and pelvic lymph node involvement (LNI) were graded as negative, indeterminate, or positive. A dominant nodule was defined as a nodule≥1.5cm. Changes in management were identified comparing pre-MRI and post-MRI plan of care. ResultsThe rates of radiographic extracapsular extension, radiographic seminal vesicle invasion, lymph node involvement, and dominant nodule were 39%, 7%, 12%, and 28%, respectively. The eMRI identified measurable disease in most patients with an increasing burden of disease (sextants involved, median nodule size) according to risk category (P<0.01). Changes in management after eMRI occurred in 18%, including 9%, 18%, and 33% of men with low-risk, intermediate-risk, or high-risk disease (P = 0.08), and 12%, 17%, and 22% of men who were candidates for active surveillance, brachytherapy as monotherapy, or external beam radiation therapy (P = 0.48), respectively. ConclusionThe eMRI influenced management in a risk-dependent fashion. Further study is required to determine the clinical importance of eMRI findings and to determine whether changes in management can lead to improved clinical outcome.

Comparison of prostate cancer detection at 3-T MRI with and without an endorectal coil: A prospective, paired-patient study

ObjectivesTo compare the sensitivity of 2 different non–endorectal coil strategies vs. endorectal coil (ERC) magnetic resonance imaging (MRI) for detection of prostate cancer (PCa). MethodsIn this prospective, single-center, paired-patient, paired-reader study, 49 men with a clinical indication for MRI underwent non-ERC (phased-array coil only) T2-weighted imaging and diffusion-weighted imaging followed by the same sequences using both ERC and phased-array coils (ERC Protocol). Patients were randomized into 1 of 2 arms: standard non-ERC protocol and augmented non-ERC protocol. Lesions with Likert score≥3 were defined as suspicious for cancer. Radical prostatectomy specimen or combined systematic plus targeted biopsies served as the standard of reference. Cancers were stratified into risk groups according to the National Comprehensive Cancer Network guidelines. Generalized estimating equations with Bonferroni correction were used for comparisons. The level of reader confidence was inferred by the Likert scores assigned to index lesions. ResultsThe ERC protocol provided sensitivity (78%) superior to MRI without ERC for PCa detection, both with a standard (43%) (P<0.0001) or augmented (60%) (P<0.01) protocol. The ERC MRI missed less-intermediate or high-risk index lesions (4%) than standard non-ERC (42%) (P = 0.02) and augmented non-ERC MRI (25%), although the latter did not reach significance (P = 0.09). The ERC improved radiologist confidence for the detection of PCa (average Likert score = 4.2±1.4) compared to standard (2.3±2.3) and augmented (2.9±2.1) non-ERC (P = 0.001). ConclusionsThe use of combined ERC and pelvic phased-array coil for T2-weighted imaging and diffusion-weighted imaging provides superior sensitivity for the detection of PCa compared to an examination performed without the ERC.

Comparison of Prostate Volume Measured by Endorectal Coil MRI to Prostate Specimen Volume and Mass After Radical Prostatectomy

To compare prostate volume measurements from 3-Tesla endorectal coil magnetic resonance imaging (ERC MRI) obtained with the prolate ellipsoid volume formula (EVF) and volumetry to pathology-based volume measurements. The institutional review board waived informed consent for this retrospective, health insurance portability and accountability act (HIPAA) compliant study, which included 195 patients who underwent 3-T ERC MRI between January 2008 and October 2011 and had pathologic prostate measurements available. Two readers in consensus measured the prostate length, height, and width on each MRI. They estimated prostate volumes using the prolate EVF (length × height × width × [π/6]) and also by performing three-dimensional volumetry. Pathologic specimen mass and dimensions were used to calculate prostate volume. Agreement was measured with Lin's concordance correlation coefficient (CCC). Volume differences were assessed using the Wilcoxon signed-rank test. Correct prostate-specific antigen (PSA) density classification rates were compared between EVF-based and volumetry-based PSA density levels using the exact McNemar test, with pathology-based PSA density as the reference standard. Concordance was high between EVF and volumetry measurements (CCC, 0.950 [95% confidence interval, 0.935-0.962]) and between both kinds of MRI measurements and pathology (both CCC > 0.80). Based on a cut-off of ≤0.15 ng/mL/cm(3), use of EVF-based volume produced correct classification of 46 of 48 PSA density levels >15 ng/mL/cm(3) and 113 of 147 PSA density levels ≤15 ng/mL/cm(3); use of volumetry-based volume produced correct classification of 47 of 48 PSA density levels >15 ng/mL/cm(3) and 121 of 147 PSA density levels ≤15 ng/mL/cm(3). Rates of underclassification (P > .95) and overclassification (P = .10) did not differ significantly between EVF and volumetry. EVF appears to be suitable for measuring prostate volume from ERC-MRI.

Multiattribute probabilistic prostate elastic registration (MAPPER): application to fusion of ultrasound and magnetic resonance imaging.

Transrectal ultrasound (TRUS)-guided needle biopsy is the current gold standard for prostate cancer diagnosis. However, up to 40% of prostate cancer lesions appears isoechoic on TRUS. Hence, TRUS-guided biopsy has a high false negative rate for prostate cancer diagnosis. Magnetic resonance imaging (MRI) is better able to distinguish prostate cancer from benign tissue. However, MRI-guided biopsy requires special equipment and training and a longer procedure time. MRI-TRUS fusion, where MRI is acquired preoperatively and then aligned to TRUS, allows for advantages of both modalities to be leveraged during biopsy. MRI-TRUS-guided biopsy increases the yield of cancer positive biopsies. In this work, the authors present multiattribute probabilistic postate elastic registration (MAPPER) to align prostate MRI and TRUS imagery. MAPPER involves (1) segmenting the prostate on MRI, (2) calculating a multiattribute probabilistic map of prostate location on TRUS, and (3) maximizing overlap between the prostate segmentation on MRI and the multiattribute probabilistic map on TRUS, thereby driving registration of MRI onto TRUS. MAPPER represents a significant advancement over the current state-of-the-art as it requires no user interaction during the biopsy procedure by leveraging texture and spatial information to determine the prostate location on TRUS. Although MAPPER requires manual interaction to segment the prostate on MRI, this step is performed prior to biopsy and will not substantially increase biopsy procedure time. MAPPER was evaluated on 13 patient studies from two independent datasets—Dataset 1 has 6 studies acquired with a side-firing TRUS probe and a 1.5 T pelvic phased-array coil MRI; Dataset 2 has 7 studies acquired with a volumetric end-firing TRUS probe and a 3.0 T endorectal coil MRI. MAPPER has a root-mean-square error (RMSE) for expert selected fiducials of 3.36 ± 1.10 mm for Dataset 1 and 3.14 ± 0.75 mm for Dataset 2. State-of-the-art MRI-TRUS fusion methods report RMSE of 3.06-2.07 mm. MAPPER aligns MRI and TRUS imagery without manual intervention ensuring efficient, reproducible registration. MAPPER has a similar RMSE to state-of-the-art methods that require manual intervention.

Performance Comparison of 1.5-T Endorectal Coil MRI with 3.0-T Nonendorectal Coil MRI in Patients with Prostate Cancer

To compare prostate morphology, image quality, and diagnostic performance of 1.5-T endorectal coil magnetic resonance (MR) imaging (MRI) and 3.0-T nonendorectal coil MRI in patients with prostate cancer. MR images obtained of 83 patients with prostate cancer using 1.5-T MRI systems with an endorectal coil were compared to images collected from 83 patients with a 3.0-T MRI system. Prostate diameters were measured, and image quality was evaluated by one American Board of Radiology (ABR)-certified radiologist (reader 1) and one ABR-certified diagnostic medical physicist (reader 2). The likelihood of the presence of peripheral zone cancer in each sextant and local extent was rated and compared to histopathologic findings. Prostate anterior-posterior diameter measured by both readers was significantly shorter with 1.5-T endorectal MRI than with 3.0-T MRI. The overall image quality score difference was significant only for reader 1. Both readers found that the two MRI systems provided a similar diagnostic accuracy in cancer localization, extraprostatic extension, and seminal vesicle involvement. Nonendorectal coil 3.0-T MRI provides prostate images that are natural in shape and that have comparable image quality to those obtained at 1.5 T with an endorectal coil, but not superior diagnostic performance. These findings suggest an opportunity exists for improving technical aspects of the 3.0-T prostate MRI.

The value of ADC, T2 signal intensity, and a combination of both parameters to assess Gleason score and primary Gleason grades in patients with known prostate cancer.

The ability to non-invasively analyze tumor aggressiveness is an important predictor for individual treatment stratification and patient outcome in prostate cancer (PCA). To evaluate: (i) whether apparent diffusion coefficient (ADC), the T2 signal intensity (SI), and a combination of both parameters allow for an improved discrimination of Gleason Score (GS) ≥7 (intermediate and high risk) and GS <7 (low risk) in PCA; and (ii) whether ADC may distinguish between 3 + 4 and 4 + 3 PCA (primary Gleason grades [pGG]). Prostatectomy specimens of 66 patients (mean age, 63 ± 5.6 years; 104 PCA foci) with a preceding multiparametric 1.5 T endorectal coil magnetic resonance imaging (MRI) were included. ADC (b values = 0, 100, 400, 800 s/mm(2)), standardized T2 (T2s), and the ADC/T2s ratio were tested for correlation with GS applying multivariate analysis. ADC cutoff values were calculated for prediction of GS and pGG, and logarithm of the odds (LOGIT) was used to express the probability for GS and pGG. Diagnostic accuracy was assessed by ROC analysis. We found an almost linear negative relationship of ADC for GS ≥7 (P = 0.002). The effect of ADC for GS ≥7 (adjusted odds ratio = 0.995) was almost identical for peripheral and transition zone PCA (P = 0.013 and P < 0.001, respectively). ADC showed an AUC of 78.9% for discrimination between GS <7 and GS ≥7. An ADC cutoff of <1.005 × 10(-3 )mm(2)/s indicated a GS ≥7 (90.5% sensitivity, 62.5% specificity). Within the group of GS = 7 PCA, an ADC > 0.762 × 10(-3 )mm(2)/s indicated a pGG of3 (AUC = 69.6%). T2s and the ADC/T2s ratio do not provide additional information regarding prediction of GS. ADC values have a good discriminatory power to distinguish tumors with GS ≥7 from GS <7 and to predict pGG in GS = 7 PCA.

MP42-03 MRI IMAGING FEATURES DIFFERENTIATING PROSTATE CANCER FROM CHRONIC PROSTATITIS

INTRODUCTION AND OBJECTIVES: Prostate cancer and chronic prostatitis can both lead to elevated prostate specific antigen (PSA). Conventional magnetic resonance imaging (MRI) imaging features distinguishing prostate cancer from chronic prostatitis are not well established and therefore differentiation of those two entities is important to avoid over and underestimation of the extent of prostate cancer. The purpose of this study was to describe characteristics of chronic prostatitis using high spatial resolution dynamic contrastenhanced MRI (HR-CE-MRI) with correlative histopathology from prostatectomy specimens. METHODS: Following IRB approval, 54 consecutive patients with prostate cancer scheduled for prostatectomy underwent pre surgical endorectal coil MRI on a 1.5 Tesla scanner between January 2012-July 2013, obtaining high-spatial resolution T2-weighted and dynamic CEMRIs of the prostate. MRI features suggestive of chronic prostatitis were compared to prostatectomy specimens. Descriptive statistics including accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (PPV) were calculated. Agreement between presence of chronic prostatitis at HR-CE-MRI and at final diagnosis was evaluated using kappa (k) statistics. RESULTS: Imaging features most suggestive of chronic prostatitis include late-enhancing pseudoseptations with fine, linear striations in a centrifugal pattern irrespective of rapid wash-in within areas with preserved pseudoseptations on dynamic HR-CE-MRI. In contrast, cancerous areas showing rapid wash-in and wash-out, never showed late enhancing fine linear striations. Of 54 patients, 46 had chronic prostatitis by histopathologic criteria; 49 had MRI findings suggestive of chronic prostatitis with 3 false positives. These findings had a sensitivity of 100%, specificity of 62.5%, PPV of 93.8%, and NPV of 100%. The accuracy (observed agreement) was 94.4%. There was substantial agreement between presence of chronic prostatitis at CE-MRI and at final diagnosis (kappa1⁄4 0.74, standard error1⁄4 0.141). CONCLUSIONS: Key imaging features distinguishing chronic prostatitis and prostate cancer were found to have a sensitivity of 100%. These preliminary results demonstrate an accurate method for distinguishing these two entities and can lead to more accurate MRI staging of prostate cancerwhichcanaffect treatment choiceandclinical outcome.

MP42-04 MAPPING OF TRUE POSITIVE, FALSE POSITIVE AND FALSE NEGATIVE LYMPH NODES AFTER SALVAGE LYMPH NODE DISSECTION IN PROSTATE CANCER PATIENTS WITH POSITIVE NODES AT 11C CHOLINE POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY

INTRODUCTION AND OBJECTIVES: Prostate cancer and chronic prostatitis can both lead to elevated prostate specific antigen (PSA). Conventional magnetic resonance imaging (MRI) imaging features distinguishing prostate cancer from chronic prostatitis are not well established and therefore differentiation of those two entities is important to avoid over and underestimation of the extent of prostate cancer. The purpose of this study was to describe characteristics of chronic prostatitis using high spatial resolution dynamic contrastenhanced MRI (HR-CE-MRI) with correlative histopathology from prostatectomy specimens. METHODS: Following IRB approval, 54 consecutive patients with prostate cancer scheduled for prostatectomy underwent pre surgical endorectal coil MRI on a 1.5 Tesla scanner between January 2012-July 2013, obtaining high-spatial resolution T2-weighted and dynamic CEMRIs of the prostate. MRI features suggestive of chronic prostatitis were compared to prostatectomy specimens. Descriptive statistics including accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (PPV) were calculated. Agreement between presence of chronic prostatitis at HR-CE-MRI and at final diagnosis was evaluated using kappa (k) statistics. RESULTS: Imaging features most suggestive of chronic prostatitis include late-enhancing pseudoseptations with fine, linear striations in a centrifugal pattern irrespective of rapid wash-in within areas with preserved pseudoseptations on dynamic HR-CE-MRI. In contrast, cancerous areas showing rapid wash-in and wash-out, never showed late enhancing fine linear striations. Of 54 patients, 46 had chronic prostatitis by histopathologic criteria; 49 had MRI findings suggestive of chronic prostatitis with 3 false positives. These findings had a sensitivity of 100%, specificity of 62.5%, PPV of 93.8%, and NPV of 100%. The accuracy (observed agreement) was 94.4%. There was substantial agreement between presence of chronic prostatitis at CE-MRI and at final diagnosis (kappa1⁄4 0.74, standard error1⁄4 0.141). CONCLUSIONS: Key imaging features distinguishing chronic prostatitis and prostate cancer were found to have a sensitivity of 100%. These preliminary results demonstrate an accurate method for distinguishing these two entities and can lead to more accurate MRI staging of prostate cancerwhichcanaffect treatment choiceandclinical outcome.

Prostate MRI: Who, when, and how? Report from a UK consensus meeting

The current pathway for men suspected of having prostate cancer [transrectal biopsy, followed in some cases by magnetic resonance imaging (MRI) for staging] results in over-diagnosis of insignificant tumours, and systematically misses disease in the anterior prostate. Multiparametric MRI has the potential to change this pathway, and if performed before biopsy, might enable the exclusion of significant disease in some men without biopsy, targeted biopsy in others, and improvements in the performance of active surveillance. For the potential benefits to be realized, the setting of standards is vital. This article summarizes the outcome of a meeting of UK radiologists, at which a consensus was achieved on (1) the indications for MRI, (2) the conduct of the scan, (3) a method and template for reporting, and (4) minimum standards for radiologists.

Role of endorectal coil magnetic resonance imaging in local staging of rectal cancer: Experience from a single center

Purpose: In order to obtain an improvement in preoperative staging accuracy for rectal cancer, new imaging modalities are now under investigation. The purpose of our study was to evaluate the accuracy of endorectal coil magnetic resonance imaging (ECMRI) in the preoperative local staging of rectal cancer and correlation with intraoperative and histopathologic staging of retrieved specimen with respect to depth of tumor invasion and lymph node metastasis. Materials and Methods: The study was a prospective one and included 38 patients with biopsy proved rectal cancer. ECMRI studies were performed on a 1.5 Tesla MR unit using a standard endorectal coil. All patients underwent surgery and a comparative evaluation of ECMRI and surgical and pathological staging was done. Accuracy, sensitivity, specificity, and positive and negative predictive value (PPV and NPV) were assessed. Results: The diagnostic accuracy of ECMRI for T1/T2 tumors was 90%; for T3 and T4 tumors accuracy was 100% each. For perirectal lymph node metastasis, the diagnostic accuracy of ECMRI was 83.3%. Conclusion: ECMRI is a reliable radiologic tool for local (T) staging of rectal cancer and has excellent diagnostic accuracy, sensitivity, and specificity. ECMRI is also useful in detecting perirectal lymph node metastasis, but accuracy is not as good as that for T staging.

Combining prostrate-specific antigen and Gleason score increases the diagnostic power of endorectal coil magnetic resonance imaging in prostate cancer pathological stage

BackgroundThe proper use of endorectal coil MRI (eMRI) images provide detailed information for the real extent of locally prostate cancer invasion and involvement of pelvic lymph nodes. This study evaluated the accuracy of endorectal coil magnetic resonance imaging (eMRI) results, combining the preoperative prostate-specific antigen (PSA), and the biopsy Gleason score to improve the diagnostic accuracy of prostate cancer (PCa) with organ-confined disease (OCD) or extracapsular extension (ECE)/seminal vesicle invasion (SVI). MethodsBetween 2001 and 2007, 94 PCa patients received eMRI testing during presurgical evaluation and underwent radical prostatectomy. As a part of routine patient workup, serum PSA level and Gleason score after pathology examination were recorded. The eMRI images were used to help assess patient PCa staging status regarding OCD or ECE/SVI. These stage assessments as evaluated through the use of MRI were compared with the final specimen pathological stage after the patients underwent radical prostatectomy. ResultsOf the total 94 patients in our study, 65 had stage pT2, 12 had stage pT3a, and 17 had stage pT3b PCa. In patients with clinical stage T2 PCa, the Gleason score significantly improved the discriminative ability of eMRI to successfully predict PCa at the OCD stage. Otherwise, in cases of clinical stage T3 PCa, accurate determination of PSA levels significantly improved eMRI predictive ability to assess ECE or SVI staging. ConclusionIn clinical stage T2 PCa patients, integrating the biopsy Gleason score improved the discriminative ability to assess OCD PCa staging. Additionally, combining the preoperative PSA levels of clinical T3 prostate cancer cases with Gleason scores significantly improved the sensitivity and accuracy of eMRI diagnosis to distinguish ECE from SVI.

Multiparametric Magnetic Resonance Imaging and Ultrasound Fusion Biopsy Detect Prostate Cancer in Patients with Prior Negative Transrectal Ultrasound Biopsies

Patients with negative transrectal ultrasound biopsies and a persistent clinical suspicion are at risk for occult but significant prostate cancer. The ability of multiparametric magnetic resonance imaging/ultrasound fusion biopsy to detect these occult prostate lesions may make it an effective tool in this challenging scenario. Between March 2007 and November 2011 all men underwent prostate 3 T endorectal coil magnetic resonance imaging. All concerning lesions were targeted with magnetic resonance imaging/ultrasound fusion biopsy. In addition, all patients underwent standard 12-core transrectal ultrasound biopsy. Men with 1 or more negative systematic prostate biopsies were included in our cohort. Of the 195 men with previous negative biopsies, 73 (37%) were found to have cancer using the magnetic resonance imaging/ultrasound fusion biopsy combined with 12-core transrectal ultrasound biopsy. High grade cancer (Gleason score 8+) was discovered in 21 men (11%), all of whom had disease detected with magnetic resonance imaging/ultrasound fusion biopsy. However, standard transrectal ultrasound biopsy missed 12 of these high grade cancers (55%). Pathological upgrading occurred in 28 men (38.9%) as a result of magnetic resonance imaging/ultrasound fusion targeting vs standard transrectal ultrasound biopsy. The diagnostic yield of combined magnetic resonance imaging/ultrasound fusion platform was unrelated to the number of previous negative biopsies and persisted despite increasing the number of previous biopsy sessions. On multivariate analysis only prostate specific antigen density and magnetic resonance imaging suspicion level remained significant predictors of cancer. Multiparametric magnetic resonance imaging with a magnetic resonance imaging/ultrasound fusion biopsy platform is a novel diagnostic tool for detecting prostate cancer and may be ideally suited for patients with negative transrectal ultrasound biopsies in the face of a persistent clinical suspicion for cancer.

Correlation of Magnetic Resonance Imaging Tumor Volume with Histopathology

The biology of prostate cancer may be influenced by the index lesion. The definition of index lesion volume is important for appropriate decision making, especially for image guided focal treatment. We determined the accuracy of magnetic resonance imaging for determining index tumor volume compared with volumes derived from histopathology. We evaluated 135 patients (mean age 59.3 years) with a mean prostate specific antigen of 6.74 ng/dl who underwent multiparametric 3T endorectal coil magnetic resonance imaging of the prostate and subsequent radical prostatectomy. Index tumor volume was determined prospectively and independently by magnetic resonance imaging and histopathology. The ellipsoid formula was applied to determine histopathology tumor volume, whereas manual tumor segmentation was used to determine magnetic resonance tumor volume. Histopathology tumor volume was correlated with age and prostate specific antigen whereas magnetic resonance tumor volume involved Pearson correlation and linear regression methods. In addition, the predictive power of magnetic resonance tumor volume, prostate specific antigen and age for estimating histopathology tumor volume (greater than 0.5 cm(3)) was assessed by ROC analysis. The same analysis was also conducted for the 1.15 shrinkage factor corrected histopathology data set. There was a positive correlation between histopathology tumor volume and magnetic resonance tumor volume (Pearson coefficient 0.633, p <0.0001), but a weak correlation between prostate specific antigen and histopathology tumor volume (Pearson coefficient 0.237, p = 0.003). On linear regression analysis histopathology tumor volume and magnetic resonance tumor volume were correlated (r(2) = 0.401, p <0.00001). On ROC analysis AUC values for magnetic resonance tumor volume, prostate specific antigen and age in estimating tumors larger than 0.5 cm(3) at histopathology were 0.949 (p <0.0000001), 0.685 (p = 0.001) and 0.627 (p = 0.02), respectively. Similar results were found in the analysis with shrinkage factor corrected tumor volumes at histopathology. Magnetic resonance imaging can accurately estimate index tumor volume as determined by histology. Magnetic resonance imaging has better accuracy in predicting histopathology tumor volume in tumors larger than 0.5 cm(3) than prostate specific antigen and age. Index tumor volume as determined by magnetic resonance imaging may be helpful in planning treatment, specifically in identifying tumor margins for image guided focal therapy and possibly selecting better active surveillance candidates.

Accuracy of preoperative endo-rectal coil magnetic resonance imaging in detecting clinical under-staging of localized prostate cancer

To assess the accuracy of intra-rectal coil magnetic resonance imaging (ER-MRI) for staging early prostate cancer (EPC). ER-MRI was performed with the Magnetom Symphony 1.5 Tesla system. ER-MRI and pathology findings were statistically correlated. One hundred and fifty-four consecutive patients underwent radical prostatectomy (RRP) for EPC (cT1c-2 Nx M0). An average age was 66, mean PSA 11.04 µg/L (median 7.33 µg/L) and mean pathologic Gleason score 6. Pathology detected 97 out of 154 patients (63 %) as EPC and 57 cases (37 %) as extra-prostate extension (EPED) (pT3) with extra-capsular extension (ECE) (pT3a) in 41 (27 %) and seminal vesicle invasion (SVI) (pT3b) in 16 (10 %). ER-MRI staged 100 patients (65 %) as cT2 and 54 (35 %) as EPED with ECE in 37 cases (24 %) and SVI in 17 (11 %). ER-MRI sensitivity, specificity, positive predictive value, negative predictive value, overall accuracy resulted respectively 0.78, 0.96, 0.86, 0.92, 0.91 for ECE as well as 0.88, 0.98, 0.82, 0.99 and 0.97 for SVI. ER-MRI was effective in detecting preoperative EPC under-staging. In the next future, multi-parametric 3-Tesla ER-MRI will be the procedure for diagnosing, staging and following-up prostate cancer patients.

Magnetic resonance imaging-based treatment planning for prostate brachytherapy.

Transrectal ultrasound (TRUS) is the standard imaging modality for planning prostate brachytherapy. However, magnetic resonance imaging (MRI) provides greater anatomic detail than TRUS. We compared treatment plans generated using TRUS, endorectal coil MRI (erMRI), and standard body array coil MRI (sMRI). Treatment plans were used from patients treated with permanent, stranded-seed (125)I brachytherapy in a prospective trial. All men underwent pretreatment planning based on TRUS, and all underwent erMRI before treatment and sMRI 30 days after the implant. Treatments for 20 consecutive patients were replanned on sMRI and erMRI images by investigators blinded to TRUS-based plans. Prostate volume/dimensions, radioactivity-to-prostate-volume ratio, and dosimetric parameters were compared. Compared with TRUS, mean prostate volume measured by erMRI was smaller, medial-lateral diameter was larger, and anterior-posterior diameter was smaller, suggesting that the endorectal coil produced anatomic distortions. Craniocaudal prostate length was smaller on both types of MRI thanon TRUS, suggesting that TRUS overestimates prostate length. Activity per volume was 7.5% lower for plans based on sMRI than on TRUS (0.901 vs. 0.974mCi/cm(3), p<0.001). sMRI plans had similar coverage of the planning target volume (PTV) (dose to 90% of the prostate [D(90)] 116.6% sMRI vs. 117.5% TRUS, p=0.526) and improved dose homogeneity (percentage of PTV receiving 150% of the prescription dose [V(150)] 47.4% sMRI vs. 53.8% TRUS, p=0.001 and percentage of PTV receiving 200% of the prescription dose [V(200)] 16.6% sMRI vs. 19.2% TRUS, p<0.001). Staging erMRI should not be routinely used for treatment planning because it produces anatomic distortion. sMRI may have treatment planning advantages over TRUS because of superior soft-tissue delineation of the prostate and adjacent normal tissue structures.

Multi-detector Row Computed Tomography (MDCT) versus Endorectal Coil Magnetic Resonance Imaging (ECMRI) in Staging of Carcinoma Rectum

BACKGROUND: Rectal cancer is one of the most common tumors in industrialized countries and one of the most common malignant tumors of the gastrointestinal tract.&#x0D; OBJECTIVE: To compare the diagnostic accuracy of MDCT and ECMRI in preoperative staging of rectal cancers and correlation with intraoperative and histo-pathologic staging of resected specimen with respect to depth of tumor invasion (T-staging), lymph node metastasis (N- staging), and extra rectal spread (M-staging).&#x0D; METHODS: The study was a prospective one and consisted of 68 patients with biopsy proved rectal carcinoma. Patients were randomly selected for either of these two staging modalities (i.e., MDCT or ECMRI) using a random number table. MDCT and ECMRI findings were compared with intraoperative and histopathologic (reference standard) findings. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of each diagnostic modality were assessed.&#x0D; RESULTS: The diagnostic accuracies of MDCT and ECMRI for T1/T2 lesions were 75% and 87.5%, respectively, the difference being significant. For T3 lesions, the diagnostic accuracies of MDCT and ECMRI were 85.2% and 100%, respectively. The diagnostic accuracy of both for T4 lesions was found to be 100%. Both ECMRI and MDCT were found to be almost equally accurate and specific in detecting perirectal lymph node involvement.&#x0D; CONCLUSION: Endorectal coil MRI is superior to MDCT in local (T) staging of tumor and has overall more diagnostic accuracy, sensitivity and specificity than MDCT. ECMRI has a less tendency to under-stage the disease. However, both ECMRI and MDCT are almost equally accurate and specific in detecting perirectal lymph node involvement. JMS 2012;15(1):32-38.

Prediction of prostate cancer extracapsular extension with high spatial resolution dynamic contrast-enhanced 3-T MRI

To assess the value of dynamic contrast-enhanced (DCE) combined with T2-weighted (T2W) endorectal coil (ERC) magnetic resonance imaging (MRI) at 3T for determining extracapsular extension (ECE) of prostate cancer. In this IRB-approved study, ERC 3-T MRI of the prostate was performed in 108 patients before radical prostatectomy. T2W fast spin-echo and DCE 3D gradient echo images were acquired. The interpretations of readers with varied experience were analysed. MRI-based staging results were compared with radical prostatectomy histology. Descriptive statistics were generated for prediction of ECE and staging accuracies were determined by the area under the receiver-operating characteristic curve. The overall sensitivity, specificity, positive predictive value and negative predictive value for ECE were 75%, 92%, 79% and 91%, respectively. Diagnostic accuracy for staging was 86%, 80% and 91% for all readers, experienced and less experienced readers, respectively. ERC 3-T MRI of the prostate combining DCE and T2W imaging is an accurate pretherapeutic staging tool for assessment of ECE in clinical practice across varying levels of reader experience. • Endorectal coil (ERC) magnetic resonance imaging is widely used for imaging prostatic disease. • ERC 3-T MRI is reasonably accurate for local prostate cancer staging. • High diagnostic accuracy is achievable across different levels of reader experience. • MRI facilitates therapeutic decisions in patients with prostate cancer.

Prostate Cancer Foci Detected on Multiparametric Magnetic Resonance Imaging are Histologically Distinct From Those Not Detected

We identified histological differences between prostate cancer foci that are detected and missed using multiparametric magnetic resonance imaging. A total of 49 patients who underwent multiparametric magnetic resonance imaging, including T2-weighted imaging, including diffusion weighted imaging and dynamic contrast enhanced imaging, before prostatectomy were enrolled in the study. One radiologist identified areas highly suspicious for tumor. One pathologist identified and categorized tumors in terms of size, Gleason score, solid tumor growth, intermixed benign glands, loose stroma, desmoplastic stroma and a high malignant epithelium-to-stroma ratio. Differences between detected and missed tumors were assessed using logistic regression analyses based on generalized estimating equations for correlated data. All histological features showed significant differences between detected and missed tumors on multiparametric magnetic resonance imaging (p<0.0001). Independent predictors of detection on multivariate analysis were size (OR 5.38, p=0.0077), Gleason score (OR 5.12, p=0.0094) and solid growth (OR 17.83, p<0.0001). Size, Gleason score and loose stroma were significant predictors of identification with diffusion weighted imaging on univariate analysis (p≤0.0245), while Gleason score (OR 17.05, p=0.0212) and solid growth (OR 34.90, p=0.0103) were independent predictors of identification with diffusion weighted imaging on multivariate analysis. Identification with T2-weighted imaging was associated with size and Gleason score (p≤0.01876). Identification with dynamic contrast enhanced imaging was associated with intermixed benign epithelium, loose stroma and a high malignant epithelium-to-stroma ratio (p≤0.0499). No combination of features served as independent predictors on multivariate analysis for T2-weighted imaging or dynamic contrast enhanced imaging. There are fundamental histological differences between detected and missed prostate tumors using magnetic resonance imaging. Insights into these differences may facilitate the prospective role of magnetic resonance imaging in counseling and treatment selection for patients with prostate cancer.

Pretreatment Endorectal Coil Magnetic Resonance Imaging Findings Predict Biochemical Tumor Control in Prostate Cancer Patients Treated With Combination Brachytherapy and External-Beam Radiotherapy

To investigate the utility of endorectal coil magenetic resonance imaging (eMRI) in predicting biochemical relapse in prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Between 2000 and 2008, 279 men with intermediate- or high-risk prostate cancer underwent eMRI of their prostate before receiving brachytherapy and supplemental intensity-modulated radiotherapy. Endorectal coil MRI was performed before treatment and retrospectively reviewed by two radiologists experienced in genitourinary MRI. Image-based variables, including tumor diameter, location, number of sextants involved, and the presence of extracapsular extension (ECE), were incorporated with other established clinical variables to predict biochemical control outcomes. The median follow-up was 49 months (range, 1-13 years). The 5-year biochemical relapse-free survival for the cohort was 92%. Clinical findings predicting recurrence on univariate analysis included Gleason score (hazard ratio [HR] 3.6, p = 0.001), PSA (HR 1.04, p = 0.005), and National Comprehensive Cancer Network risk group (HR 4.1, p = 0.002). Clinical T stage and the use of androgen deprivation therapy were not correlated with biochemical failure. Imaging findings on univariate analysis associated with relapse included ECE on MRI (HR 3.79, p = 0.003), tumor size (HR 2.58, p = 0.04), and T stage (HR 1.71, p = 0.004). On multivariate analysis incorporating both clinical and imaging findings, only ECE on MRI and Gleason score were independent predictors of recurrence. Pretreatment eMRI findings predict for biochemical recurrence in intermediate- and high-risk prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Gleason score and the presence of ECE on MRI were the only significant predictors of biochemical relapse in this group of patients.

Impact of Multiparametric Endorectal Coil Prostate Magnetic Resonance Imaging on Disease Reclassification Among Active Surveillance Candidates: A Prospective Cohort Study

We report magnetic resonance imaging findings among unselected men with low risk prostate cancer before active surveillance. We prospectively enrolled men with low grade, low risk, localized prostate cancer. All patients underwent multiparametric endorectal coil magnetic resonance imaging and were offered confirmatory biopsy within 1 year of imaging. The primary outcome was the impact of magnetic resonance imaging on identifying patients who were reclassified by confirmatory biopsy as no longer fulfilling active surveillance criteria. We further identified clinical parameters associated with reclassification. The cohort was stratified as patients with 1) normal magnetic resonance imaging, 2) cancer on magnetic resonance imaging concordant with initial biopsy (less than 1 cm) and 3) cancer on magnetic resonance imaging larger than 1 cm. We performed univariate analysis to assess differences in clinical parameters among the groups. Magnetic resonance imaging did not detect cancer in 23 cases (38%) while magnetic resonance imaging and initial biopsy were concordant in 24 (40%). Magnetic resonance imaging detected a 1 cm or larger lesion in 13 patients (22%). Of the cases 18 (32.14%) were reclassified. When no cancer was identified on magnetic resonance imaging, only 2 cases (3.5%) were reclassified. The positive and negative predictive values for magnetic resonance imaging predicting reclassification were 83% (95% CI 73-93) and 81% (95% CI 71-91), respectively. Prostate specific antigen density was increased in patients with lesions larger than 1 cm on magnetic resonance imaging compared to those with no cancer on imaging (median 0.15 vs 0.07 ng/ml/cc, p=0.016). Magnetic resonance imaging appears to have a high yield for predicting reclassification among men who elect active surveillance. Upon confirmation of our results magnetic resonance imaging may be used to better select and guide patients before active surveillance.