Endorectal Coil Magnetic Resonance Imaging Research Articles

Use of MR Imaging to Determine Preservation of the Neurovascular Bundles at Robotic-assisted Laparoscopic Prostatectomy

To determine whether findings at preoperative endorectal coil magnetic resonance (MR) imaging influence the decision to preserve neurovascular bundles and the extent of surgical margins in robotic-assisted laparoscopic prostatectomy (RALP). This study was approved by the investigational review board and was compliant with the HIPAA; the requirement to obtain informed consent was waived. The authors prospectively evaluated 104 consecutive men with biopsy-proved prostate cancer who underwent preoperative endorectal coil MR imaging of the prostate and subsequent RALP. MR imaging was performed at 1.5 T between January 2004 and April 2008 and included T2-weighted imaging (n = 104), diffusion-weighted imaging (n = 88), dynamic contrast-enhanced imaging (n = 51), and MR spectroscopy (n = 91). One surgeon determined the planned preoperative extent of resection bilaterally on the basis of clinical information and then again after review of the final MR imaging report. The differences in the surgical plan before and after review of the MR imaging report were determined and compared with the actual surgical and pathologic results by using logistic regression analysis. Continuous and ranked variables underwent Pearson and Spearman analysis. After review of MR imaging results, the initial surgical plan was changed in 28 of the 104 patients (27%); the surgical plan was changed to a nerve-sparing technique in 17 of the 28 patients (61%) and to a non-nerve-sparing technique in 11 (39%). Seven of the 104 patients (6.7%) had positive surgical margins. In patients whose surgical plan was changed to a nerve-sparing technique, there were no positive margins on the side of the prostate with a change in treatment plan. Preoperative prostate MR imaging data changed the decision to use a nerve-sparing technique during RALP in 27% of patients in this series.

Comparison of Pelvic Phased-Array versus Endorectal Coil Magnetic Resonance Imaging at 3 Tesla for Local Staging of Prostate Cancer

PurposeSeveral studies have demonstrated the superiority of endorectal coil magnetic resonance imaging (MRI) over pelvic phased-array coil MRI at 1.5 Tesla for local staging of prostate cancer. However, few have studied which evaluation is more accurate at 3 Tesla MRI. In this study, we compared the accuracy of local staging of prostate cancer using pelvic phased-array coil or endorectal coil MRI at 3 Tesla.Materials and MethodsBetween January 2005 and May 2010, 151 patients underwent radical prostatectomy. All patients were evaluated with either pelvic phased-array coil or endorectal coil prostate MRI prior to surgery (63 endorectal coils and 88 pelvic phased-array coils). Tumor stage based on MRI was compared with pathologic stage. We calculated the specificity, sensitivity and accuracy of each group in the evaluation of extracapsular extension and seminal vesicle invasion.ResultsBoth endorectal coil and pelvic phased-array coil MRI achieved high specificity, low sensitivity and moderate accuracy for the detection of extracapsular extension and seminal vesicle invasion. There were statistically no differences in specificity, sensitivity and accuracy between the two groups.ConclusionOverall staging accuracy, sensitivity and specificity were not significantly different between endorectal coil and pelvic phased-array coil MRI.

Multiparametric 3T Prostate Magnetic Resonance Imaging to Detect Cancer: Histopathological Correlation Using Prostatectomy Specimens Processed in Customized Magnetic Resonance Imaging Based Molds

We determined the prostate cancer detection rate of multiparametric magnetic resonance imaging at 3T. Precise one-to-one histopathological correlation with magnetic resonance imaging was possible using prostate magnetic resonance imaging based custom printed specimen molds after radical prostatectomy. This institutional review board approved prospective study included 45 patients (mean age 60.2 years, range 49 to 75) with a mean prostate specific antigen of 6.37 ng/ml (range 2.3 to 23.7) who had biopsy proven prostate cancer (mean Gleason score of 6.7, range 6 to 9). Before prostatectomy all patients underwent prostate magnetic resonance imaging using endorectal and surface coils on a 3T scanner, which included triplane T2-weighted magnetic resonance imaging, apparent diffusion coefficient maps of diffusion weighted magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging and spectroscopy. The prostate specimen was whole mount sectioned in a customized mold, allowing geometric alignment to magnetic resonance imaging. Tumors were mapped on magnetic resonance imaging and histopathology. Sensitivity, specificity, positive predictive value and negative predictive value of magnetic resonance imaging for cancer detection were calculated. In addition, the effects of tumor size and Gleason score on the sensitivity of multiparametric magnetic resonance imaging were evaluated. The positive predictive value of multiparametric magnetic resonance imaging to detect prostate cancer was 98%, 98% and 100% in the overall prostate, peripheral zone and central gland, respectively. The sensitivity of magnetic resonance imaging sequences was higher for tumors larger than 5 mm in diameter as well as for those with higher Gleason scores (greater than 7, p <0.05). Prostate magnetic resonance imaging at 3T allows for the detection of prostate cancer. A multiparametric approach increases the predictive power of magnetic resonance imaging for diagnosis. In this study accurate correlation between multiparametric magnetic resonance imaging and histopathology was obtained by the patient specific, magnetic resonance imaging based mold technique.

Endorectal magnetic resonance imaging has limited clinical ability to preoperatively predict pT3 prostate cancer

• To assess the clinical value of preoperative knowledge of the presence of extracapsular extension (ECE) or seminal vesicle invasion (SVI) in the planning for prostatectomy. • An institutional database of 1161 robotic-assisted laparoscopic prostatectomies (RALP) performed by a single surgeon (D.B.S.) was queried for those who underwent endorectal coil magnetic resonance imaging (erMRI) before robotic-assisted laparoscopic prostatectomy. • erMRI reports were dichotomized into positive or negative and compared with the final histopathology. The erMRIs performed at academic centres were compared with those performed in non-academic settings. • A sub-group of high-risk patients was also analyzed for erMRI accuracy. • The 179 patients who underwent erMRI had significantly worse disease compared to the 982 patients without imaging. Of the 110 patients with histopathologically organ-confined disease, 81 (74%) were correctly diagnosed as such on erMRI, whereas 29 (26%) were felt to have cT3 disease and constituted false-positives. Among the 69 patients with pT3 disease, erMRI correctly predicted 30 (43%), whereas 39 (57%) were incorrectly considered organ-confined. • The overall sensitivity and specificity for diagnosing pT3 disease was 43% and 73%. • When stratified by pT3a and pT3b, the sensitivity and specificity of erMRI to accurately diagnose ECE is 33% and 81%, respectively. In evaluating SVI, erMRI has a sensitivity and specificity of 33% and 89%, respectively. The positive predictive value of erMRI to assess for ECE and SVI is 50% in both, with a negative predictive value of 61% and 63%, respectively. • erMRIs performed at academic centres compared to non-academic locations demonstrated similar rates of sensitivity at 67% vs 77% and specificity at 39% vs 54%, respectively (P = 0.33). • In the setting of the present study, which was designed to be more reflective of current practice patterns in the USA, erMRI has limited clinical value in preoperatively detecting ECE and SVI. • The accuracy of detecting T3 disease did not improve in academic centres or in high-risk patients.

The Role of Preoperative Endo-rectal Coil Magnetic Resonance Imaging in Predicting Surgical Difficulty for Robotic Prostatectomy

To determine whether pelvimetry on endo-rectal coil magnetic resonance imaging (eMRI) predicts surgical difficulty of robot-assisted laparoscopic prostatectomy (RALP). Patients' records with preoperative eMRI in our RALP database from April 2008 thru May 2009 were reviewed. Demographic, preoperative clinical data, and eMRI anatomic measurements, including calculated prostate volume (PV) and the pelvic cavity index (PCI), were recorded. PCI is the pelvic inlet multiplied by the interspinous distance and divided by the pelvic depth; PCI estimates the robotic working space. Correlative and multiple regression analyses of clinical and pelvimetric data were performed for prediction of estimated blood loss (EBL), operative time (OT), positive surgical margin (PSM), and transfusion rate as surrogates of surgical difficulty. Prostatic transverse diameter, PV, and the PV-to-PCI ratio were significantly correlated with both OT and EBL (P < .05). Body mass index also correlated with EBL (P < .05). Multiple linear regression analysis demonstrated that the PV-to-PCI ratio significantly predicts OT and EBL. No factor significantly predicted PSM status or transfusion rate on regression analysis. Analysis within the PSM group revealed that those with an apical PSM had statistically narrower and deeper pelvises. Patients with larger prostates and with narrow, deep pelvises are predicted to have a more difficult RALP. The PV-to-PCI ratio statistically predicts lengthier and bloodier procedures. However, that ratio does not predict PSM or transfusion risk on regression analysis. The eMRI predicts the level of surgical difficulty and is a valuable adjunctive study to obtain before RALP.

Diagnostic accuracy of surface coil magnetic resonance imaging at 1.5 T for local staging of elevated risk prostate cancer

Preoperative prostate cancer stage predicts prognosis and affects treatment decisions. The purpose of this study was to estimate the sensitivity and specificity of surface coil magnetic resonance imaging (MRI) for prostate cancer stage using surgical pathologic data as the reference standard. High-risk patients (>/=cT3 or PSA >/=20 ng/mL or Gleason >/=8) and selected intermediate-risk patients (clinically bulky disease on exam or biopsy, cT2b/c, or Gleason 7 with >/=3 of 5 biopsy cores positive in a lobe) routinely received a pelvic MRI at our institution. The images of identified patients were reviewed by one radiologist who was blinded to clinical information. The radiologist reported presence or absence of tumour within each lobe of the prostate. Extraprostatic extension (EPE), seminal vesicle (SV) invasion and pelvic lymph node (PLN) metastasis were also reported. Radiological findings were compared with prostatectomy pathology reports. During the study period, about 320 radical prostatectomies were performed. Of these, 32 had a preoperative surface coil pelvic MRI adequate for analysis. Pathologically, 53 of 64 (82.8%) prostate lobes contained tumour, 17 (26.6%) lobes had associated EPE, 12 (18.8%) had SV involvement and 7 (10.9%) sets of PLNs contained cancer. Magnetic resonance imaging sensitivity and specificity were, respectively, 94.3% and 81.8% for tumour location, 82.4% and 87.2% for EPE, 83.3% and 92.3% for SV invasion and 71.4% and 94.7% for PLN involvement. Surface coil MRI accurately stages many prostate cancer patients with elevated risk of extraprostatic disease. This mode of imaging may be reasonable at centres that do not have endorectal coil MRI.

Urethral Diverticula in Women: Discrepancies Between Magnetic Resonance Imaging and Surgical Findings

Some groups consider magnetic resonance imaging the gold standard to diagnose urethral diverticula with up to 100% reported sensitivity. We describe cases contradicting this paradigm and identify reasons for discrepancies. We searched a database for women who underwent urethral diverticulum surgery from 1998 to 2008 and also underwent preoperative magnetic resonance imaging. Images were reviewed by a blinded panel of urologists and a radiologist. They came to consensus on the presence or absence, site and anatomy of urethral diverticulum or cancer, and compared operative findings. Discrepancies were classified as errors in urethral diverticulum or cancer diagnosis and errors in urethral diverticulum anatomy or site. Of 76 patients who underwent diverticulectomy 41 also underwent magnetic resonance imaging, of whom 10 (24.4%) had a discrepancy between magnetic resonance imaging and surgical findings. In 6 of these cases there were diagnosis errors and diverticula were not seen on magnetic resonance imaging in 3. One urethral diverticulum each was misdiagnosed as Bartholin's cyst and as a typical post-collagen injection appearance. A sterile abscess was incorrectly diagnosed as a urethral diverticulum. In 2 patients magnetic resonance imaging did not detect cancer within the diverticulum. A major discrepancy in anatomy made intraoperative decision making difficult in 2 patients. In cases clinically suspicious for urethral diverticulum magnetic resonance imaging had a 24.4% error rate. Serious consequences are failure to detect cancer and suboptimal treatment for urethral diverticulum. The reason for the high magnetic resonance imaging accuracy rate in other series may be that in the absence of radiological confirmation some surgeons may choose not to perform surgery. Magnetic resonance imaging is useful to assess urethral diverticula but physicians should be aware of its limitations.

Topographical Sensitivity and Specificity of Endorectal Coil Magnetic Resonance Imaging for Prostate Cancer Detection

Objectives: Endorectal coil magnetic resonance imaging (EC-MRI) is useful to evaluate prostate cancer localization. Herein, we evaluate sensitivity and specificity of EC-MRI in different regions of the prostate by comparing the acquired images to whole-mount sections of the prostate after radical prostatectomy. Methods: 69 patients with localized prostate cancer were included. After virtually dividing the prostate into 12 sectors, results of EC-MRI were compared to corresponding whole-mount sections by contingency analysis. Sensitivity and specificity were calculated for each of the 12 areas as well as for the dorsal and ventral region. Results: Sensitivity right/left was dorsal apex/mid/base 41/41, 60/67 and 73/79%; ventral 33/52, 43/42 and 47/52%. Specificity right/left was dorsal apex/mid/base 92/89, 82/75 and 88/69%; ventral 100/100, 100/92 and 88/83%. Local sensitivity and specificity regarding dorsal versus ventral was 88/100 and 65/87%. Conclusions: Local sensitivity decreased from basodorsal to apicoventral direction, whereas local specificity increased in the same direction. Therefore, prostate cancers demonstrated by MRI are more prone to be detected in the basodorsal region, whereas less false-positive results are found in the apicoventral region. These variations in topographical specificity and sensitivity need to be considered before radical prostatectomy or MRI-guided biopsy.

Phase II trial of neoadjuvant docetaxel and gefitinib followed by radical prostatectomy in patients with high‐risk, locally advanced prostate cancer

Prostate cancer trials investigating neoadjuvant hormonal therapy, followed by surgery, have demonstrated that elimination of all tumor cells from the primary site is rare. The authors report a phase 2 trial assessing the efficacy and toxicity of docetaxel and gefitinib in patients with high-risk localized prostate cancer as neoadjuvant therapy before radical prostatectomy (RP). Thirty-one patients with high-risk prostate cancer were treated with docetaxel and gefitinib for 2 months before RP. All patients met the criteria of clinical stage T2b-3 or serum prostate-specific antigen (PSA) level >20 ng/mL, or Gleason score of 8 to 10. The primary endpoint was pathologic complete response. Secondary objectives included clinical response. When available, endorectal coil magnetic resonance imaging (eMRI) was performed as part of clinical response evaluation. Immunohistochemical staining of epidermal growth factor receptor and HER-2/neu was performed on prechemotherapy and postchemotherapy prostate tissue. The median age of the patients was 60 years, the median pretreatment PSA level was 7.43 ng/mL, and the median Gleason score was 8. Clinical staging prior to treatment consisted of: T1 in 4 patients, T2 in 17 patients, and T3 in 10 patients. One patient with enlarged pelvic adenopathy and T4 disease did not undergo RP. Thirty patients received all scheduled therapies including RP. Grade 3 toxicities included asymptomatic liver function test elevation in 4 (13%) patients, diarrhea in 1 (3%) patient, and fatigue in 1 (3%) patient. One patient experienced grade 4 toxicity with elevated alanine aminotransferase. RP specimen pathology demonstrated residual carcinoma in all cases. Twenty-nine (94%) patients achieved a clinical partial response, including 35% of patients who demonstrated radiographic improvement on eMRI. No pathologic complete response was noted in 31 patients treated with docetaxel and gefitinib. This combination was well tolerated, and did not result in increased surgical morbidity.

The role of endorectal coil MRI in preoperative staging and decision-making for the treatment of clinically localized prostate cancer

The optimal management of newly diagnosed prostate cancer requires individualization of the treatment plan based upon the most accurate clinical characterization of tumor location and extent of disease. The role of imaging in prostate cancer staging continues to evolve. In this review, we address the utility of endorectal coil magnetic resonance imaging (eMRI) in both local staging and its ability to facilitate the decision in choosing one treatment strategy over another after the initial diagnosis of localized prostate cancer. Using the PubMed database and reference lists of key articles, we identified studies addressing the use of eMRI in tumor characterization and risk stratification in patients undergoing treatment for clinically localized prostate cancer. The findings identified within 54 selected studies were incorporated into a summary discussing the current limitations in cancer staging and the role eMRI plays in both the preoperative assessment and clinical decision-making in an attempt to improve our ability to individualize management approaches and tailor treatment. eMRI allows for more accurate local staging by complementing the existing clinical variables through improvements in spatial characterization of the prostatic zonal anatomy and molecular changes. These improvements in tumor staging enhance our ability to individualize treatment selection and tailor the approach to maximize cancer control while minimizing treatment related morbidity.

3-T MRI with Phased-array Coil in Local Staging of Prostatic Cancer

To evaluate the diagnostic accuracy of a 3-T magnetic resonance imaging (MRI) system with a phased-array coil (3T MRI) in the local staging of prostatic cancer. Between July 2004 and September 2007, 59 patients (mean age 66 years) with a histologic diagnosis of prostatic cancer underwent 3-T MRI with a phased-array coil. A total of 42/59 patients underwent a radical prostatectomy within 3 weeks of the MRI examination. Two radiologists with differing experience in the interpretation of prostatic imaging used a 1-5 scale score to assess extracapsular spread, seminal vesicle and neurovascular bundle infiltration, and prostatic apex involvement. The anatomopathologic examination conducted on histologic macrosections was the reference test used to evaluate the results of 3-T MRI. Interobserver reliability was assessed using the k value. The sensitivity, specificity, and accuracy values obtained by the expert radiologist were 68%, 92%, and 83%, respectively, compared to 50%, 85%, and 71% for the identification of extracapsular spread and 81%, 62%, and 84% compared to 63%, 50%, and 55% for apex involvement. Interobserver reliability was good (k=0.71). Seminal vesicle infiltration was correctly identified in four of five cases and neurovascular bundle infiltration was identified in four of four cases. Despite presenting diagnostic accuracy values lower than those reported in literature using 1.5-T endorectal coil MRI, the use of 3-T MRI with a phased-array coil could constitute a valid alternative to MRI techniques using endorectal coils in selected patients. Direct comparative studies between the two methods on large caseloads are required to confirm this hypothesis.

Optimal Methods for Staging Rectal Cancer

At present, several modalities exist for the preoperative staging of rectal lesions, including computed tomography (CT), body coil or endorectal coil magnetic resonance imaging (MRI), endoscopic ultrasonography (EUS) done by rigid or flexible probes, and positron emission tomography (PET). Staging accuracy for CT ranges from 53% to 94% for T-stage accuracy and from 54% to 70% for N-stage accuracy. Improved CT accuracy is observed at higher disease stages. Body coil MRI has shown T- and N-stage accuracy ranging from 59% to 95% and 39% to 95%, respectively. Endorectal coil MRI has shown improved T- and N-stage accuracy, with rates of 66% to 91% and 72% to 79%, respectively. The development of phased-array MRI, combining high spatial resolution with a larger field of view, offers promise to improve on these rates. EUS, considered the current gold standard, has shown T-stage accuracy ranging from 75% to 95%, with N-stage accuracy ranging from 65% to 80%. Flexible EUS probes have the advantage of being able to access and sample iliac nodes. Recent studies also suggest that three-dimensional EUS may provide greater accuracy than conventional two-dimensional EUS. Limited studies exist on the use of PET in primary tumor staging. PET may upstage disease in 8% to 24% of patients and has also been used in posttreatment restaging and surveillance. Postradiation edema, necrosis, and fibrosis seem to decrease restaging accuracy in all modalities. This article reviews the current literature about the staging accuracy of the various modalities and suggests a staging algorithm for rectal cancer.

Development of Multiorgan Finite Element-Based Prostate Deformation Model Enabling Registration of Endorectal Coil Magnetic Resonance Imaging for Radiotherapy Planning

Endorectal coil (ERC) magnetic resonance imaging (MRI) provides superior visualization of the prostate compared with computed tomography at the expense of deformation. This study aimed to develop a multiorgan finite element deformable method, Morfeus, to accurately co-register these images for radiotherapy planning. Patients with prostate cancer underwent fiducial marker implantation and computed tomography simulation for radiotherapy planning. A series of axial MRI scans were acquired with and without an ERC. The prostate, bladder, rectum, and pubic bones were manually segmented and assigned linear elastic material properties. Morfeus mapped the surface of the bladder and rectum between two imaged states, calculating the deformation of the prostate through biomechanical properties. The accuracy of deformation was measured as fiducial marker error and residual surface deformation between the inferred and actual prostate. The deformation map was inverted to deform from 100 cm(3) to no coil. The data from 19 patients were analyzed. Significant prostate deformation occurred with the ERC (mean intrapatient range, 0.88 +/- 0.25 cm). The mean vector error in fiducial marker position (n = 57) was 0.22 +/- 0.09 cm, and the mean vector residual surface deformation (n = 19) was 0.15 +/- 0.06 cm for deformation from no coil to 100-cm(3) ERC, with an image vector resolution of 0.22 cm. Accurately deformed MRI scans improved soft-tissue resolution of the anatomy for radiotherapy planning. This method of multiorgan deformable registration enabled accurate co-registration of ERC-MRI scans with computed tomography treatment planning images. Superior structural detail was visible on ERC-MRI, which has potential for improving target delineation.

Role of Endorectal Coil Magnetic Resonance Imaging in Treatment of Patients with Prostate Cancer and in Determining Radical Prostatectomy Surgical Margin Status: Report of a Single Surgeon’s Practice

To evaluate the role of the combination of endorectal coil and external multicoil array magnetic resonance imaging (MRI) in the management of prostate cancer and predicting the surgical margin status in a single-surgeon practice. We reviewed all patients referred by a single surgeon from January 1993 to May 2002 for staging prostate MRI before selecting treatment. All MRI examinations were performed using 1.5T (Signa, GE Medical Systems) with a combination of endorectal and pelvic multicoil array. The tumor size, stage, and total gland volume on MRI, prostate-specific antigen (PSA) level, and Gleason score were all compared with the pathologic stage and diagnosis of positive surgical margins (PSMs). A total of 232 patients were evaluated, of whom 110 underwent radical prostatectomy, all performed by one surgeon (group 1), and 122 did not (group 2). The results showed that MRI stage, PSA level, and age were all significantly different (P <0.001). In group 1, the results showed a high specificity (99%) and accuracy (91%) for MRI staging of T3 cancer. The postoperative follow-up (median 4.5 years) revealed that 90% of men had PSA levels of less than 0.1 ng/mL. The PSM rate was 16%. No significant difference was found on MRI between the PSM group and non-PSM group. A single tumor length greater than 1.8 cm was the cutpoint above which PSMs were found (P = 0.002). The results of our study have shown that the combined use of clinical data and endorectal MRI can help optimize patient treatment and selection for surgery and, in a single surgeon's practice, lead to successful outcomes.

Prostate Cancer: Body-Array versus Endorectal Coil MR Imaging at 3 T—Comparison of Image Quality, Localization, and Staging Performance

To prospectively compare image quality and accuracy of prostate cancer localization and staging with body-array coil (BAC) versus endorectal coil (ERC) T2-weighted magnetic resonance (MR) imaging at 3 T, with histopathologic findings as the reference standard. After institutional review board approval and written informed consent, 46 men underwent 3-T T2-weighted MR imaging with a BAC (voxel size, 0.43 x 0.43 x 4.00 mm) and an ERC (voxel size, 0.26 x 0.26 x 2.50 mm) before radical prostatectomy. Four radiologists independently evaluated data sets obtained with the BAC and ERC separately. Ten image quality characteristics related to prostate cancer localization and staging were assigned scores. Prostate cancer presence was recorded with a five-point probability scale in each of 14 segments that included the whole prostate. Disease stage was classified as organ-confined or locally advanced with a five-point probability scale. Whole-mount-section histopathologic examination was the reference standard. Areas under the receiver operating characteristic curve (AUCs) and diagnostic performance parameters were determined. A difference with a P value of less than .05 was considered significant. Forty-six patients (mean age, 61 years) were included for analysis. Significantly more motion artifacts were present with ERC imaging (P<.001). All other image quality characteristics improved significantly (P<.001) with ERC imaging. With ERC imaging, the AUC for localization of prostate cancer was significantly increased from 0.62 to 0.68 (P<.001). ERC imaging significantly increased the AUCs for staging, and sensitivity for detection of locally advanced disease by experienced readers was increased from 7% (one of 15) to a range of 73% (11 of 15) to 80% (12 of 15) (P<.05), whereas a high specificity of 97% (30 of 31) to 100% (31 of 31) was maintained. Extracapsular extension as small as 0.5 mm at histopathologic examination could be accurately detected only with ERC imaging. Image quality and localization improved significantly with ERC imaging compared with BAC imaging. For experienced radiologists, the staging performance was significantly better with ERC imaging.

Magnetic resonance imaging‐directed transrectal ultrasonography‐guided biopsies in patients at risk of prostate cancer

To evaluate whether using endorectal-coil magnetic resonance imaging (erMRI) before transrectal ultrasonography (TRUS)-guided biopsies of the prostate increases the yield of cancer in a high-risk population, and in a subset analysis to compare the yield with high-field (3 T) vs lower field (1.5 T) MRI. Between March 2003 and November 2005, 26 consecutive patients had erMRI before their TRUS biopsy of the prostate (median age 62 years, range 32-76). The median prostate-specific antigen (PSA) level was 8.40 (2.1-85.9) ng/mL. All patients had at least one previous negative prostate biopsy (median 3, range 1-12). Twenty-three patients had at least one risk factor for prostate cancer (family history, high PSA velocity, low percentage of free PSA, prostatic intraepithelial neoplasia or atypical small acinar proliferation on previous biopsy). MRI studies consisted of T2-weighted and dynamic contrast-enhanced (DCE) imaging studies. There was a close correlation between T2-weighted and DCE images (85% agreement, P<0.001). Neither T2-weighted nor DCE imaging correlated with a higher yield for cancer on final biopsy (T2, positive predictive value, PPV, 20%, negative PV, NPV, 14%, P=0.21; DCE, PPV 21%, NPV 15%, P=0.26). Combining the two methods did not improve the cancer yield. There was no significant difference in the probability of cancer based on 1.5 T or 3 T imaging (17% vs 16%, P=0.88). Although erMRI before TRUS-guided biopsies tended to give higher cancer yields the difference was not statistically significant. Reasons for this might include suboptimal localisation of the MRI findings and the biopsy location. Better methods for fusing MRI and TRUS images are presently being developed at our institution to allow more accurate targeting.

18F‐choline and/or 11C‐acetate positron emission tomography: detection of residual or progressive subclinical disease at very low prostate‐specific antigen values (&lt;1 ng/mL) after radical prostatectomy

To assess the value of positron emission tomography (PET)/computed tomography (CT) with either (18)F-choline and/or (11)C-acetate, of residual or recurrent tumour after radical prostatectomy (RP) in patients with a prostate-specific antigen (PSA) level of <1 ng/mL and referred for adjuvant or salvage radiotherapy. In all, 22 PET/CT studies were performed, 11 with (18)F-choline (group A) and 11 with (11)C-acetate (group B), in 20 consecutive patients (two undergoing PET/CT scans with both tracers). The median (range) PSA level before PET/CT was 0.33 (0.08-0.76) ng/mL. Endorectal-coil magnetic resonance imaging (MRI) was used in 18 patients. Nineteen patients were eligible for evaluation of biochemical response after salvage radiotherapy. There was abnormal local tracer uptake in five and six patients in group A and B, respectively. Except for a single positive obturator lymph node, there was no other site of metastasis. In the two patients evaluated with both tracers there was no pathological uptake. Endorectal MRI was locally positive in 15 of 18 patients; 12 of 19 responded with a marked decrease in PSA level (half or more from baseline) 6 months after salvage radiotherapy. Although (18)F-choline and (11)C-acetate PET/CT studies succeeded in detecting local residual or recurrent disease in about half the patients with PSA levels of <1 ng/mL after RP, these studies cannot yet be recommended as a standard diagnostic tool for early relapse or suspicion of subclinical minimally persistent disease after surgery. Endorectal MRI might be more helpful, especially in patients with a low likelihood of distant metastases. Nevertheless, further research with (18)F-choline and/or (11)C-acetate PET with optimal spatial resolution might be needed for patients with a high risk of distant relapse after RP even at low PSA values.

Preoperative and Intraoperative Risk Factors for Side-Specific Positive Surgical Margins in Laparoscopic Radical Prostatectomy for Prostate Cancer

ObjectivesIdentification of variables predicting positive surgical margins (PSMs) in patients undergoing laparoscopic radical prostatectomy (LRP) for clinically localized prostate cancer is lacking. Our objective was to determine preoperative risk factors and the association of ipsilateral degree of neurovascular bundle dissection (intraoperative factor) with side-specific PSMs in these patients. Material and methodsBetween October 2002 and April 2005, one surgeon performed LRP on 407 previously untreated patients. Of 814 evaluable prostate sides, 728 harboured prostate cancer in the specimen and composed the study population. For each prostate side, we obtained clinical stage, biopsy Gleason, maximum percentage of tumour in the biopsy, suspected extracapsular extension (ECE) on endorectal coil magnetic resonance imaging (MRI), degree of neurovascular bundle (NVB) dissection, and PSMs. PSM was defined as cancer cells at the inked margins. Logistic regression analyses with random effects were generated. ResultsOf the 728 prostate sides with cancer, 51 (7%) had at least one PSM. In multivariable analysis, higher PSA (p=0.01), Gleason score of 7 compared with ≤6 in the biopsy (p=0.04), lower prostate volume on MRI (p=0.01), and interfascial NVB dissection compared with intrafascial dissection (p=0.01) were associated with an increased risk of side-specific PSMs. Suspected ECE on MRI (p=0.9) and clinical stage (p=0.3) were not significantly associated with side-specific PSMs. A subset analysis of 321 patients with bilateral tumours did not show statistically significant differences in PSMs according to tumour side (p=0.3). ConclusionsHigh serum prostate-specific antigen, biopsy Gleason score of 7, low prostate volume, and interfascial NVB dissection were independently associated with side-specific PSMs after LRP, and should be considered during planning of the LRP surgical strategy.

184 Accurately co-registering endorectal coil magnetic resonance images (ERC-MRI) using a multi-organ finite element-based prostate deformation model

184 Accurately co-registering endorectal coil magnetic resonance images (ERC-MRI) using a multi-organ finite element-based prostate deformation model

199 Development of a prostate deformation model to enable accurate registration of endorectal coil magnetic resonance images (ERC-MRI)

199 Development of a prostate deformation model to enable accurate registration of endorectal coil magnetic resonance images (ERC-MRI)