Organ-Confined Prostate Cancer: Effect of Prior Transrectal Biopsy on Endorectal MRI and MR Spectroscopic Imaging

Incorporating endorectal MR elastography into multi-parametric MRI for prostate cancer imaging: Initial feasibility in volunteers

PURPOSE

To investigate the tolerability and technical feasibility of performing endorectal MR elastography (eMRE) in human volunteers within the representative age group commonly affected by prostate cancer.

MATERIALS AND METHODS

Endorectal MRE was conducted on seven volunteers in a 1.5 Tesla (T) MR imager using a rigid endorectal coil. Another five volunteers were imaged on a 3T MR imager using an inflatable balloon type endorectal coil. Tolerability was accessed for vibration amplitudes of ±1-50 μm and for frequencies of 100-300 Hz.

RESULTS

All 12 volunteers tolerated the displacements necessary to successfully perform eMRE. Shear waves with frequencies up to 300 Hz could propagate across the entire prostate using both coil designs.

CONCLUSION

The results of this study motivate further investigation of eMRE in prostate cancer patients to help determine if there is an added value of integrating eMRE into existing multi-parametric prostate MRI exams.

Prostate cancer imaging: what the urologist wants to know

No consensus exists at present regarding the use of imaging for the evaluation of prostate cancer. Ultrasonography is mainly used for biopsy guidance and magnetic resonance imaging is the mainstay in evaluating the extent of local tumor. Computed tomography and radionuclide bone scanning are mainly reserved for assessment of advanced disease. Positron emission tomography is gaining acceptance in the evaluation of treatment response and recurrence. The combination of anatomic, functional, and metabolic imaging modalities has promise to improve treatment. This article reviews current imaging techniques and touches on the evolving technologies being used for detection and follow-up of prostate cancer.

Effects of post biopsy digital rectal compression on improving prostate cancer staging using magnetic resonance imaging in localized prostate cancer

PURPOSE

To evaluate the effectiveness of digital rectal-compression immediately after transrectal prostate biopsy (P-bx) for improving the accuracy of prostate cancer (PCa) staging.

MATERIALS AND METHODS

Between July 2008 and June 2010, 94 consecutive patients who had a radical prostatectomy were included in our retrospective analysis. The exclusion criteria included a history of previous P-bx and surgery, a biopsy performed in another hospital, a number of biopsy cores different from 12, or a condition interfering with bleeding assessment. The subjects were divided into two groups, compression and non-compression. All enrolled patients took magnetic resonance imaging (MRI) for PCa staging.

RESULTS

The compression and non-compression groups were comparable with respect to several baseline characteristics. However, the total hemorrhage score of intraprostatic bleeding was significantly different between the groups, even with adjustment for the time from biopsy to MRI (compression:15.4 ± 2.32, non-compression: 24.9 ± 2.43, p<0.001). The intra-prostatic cancer location matching rate was higher in the compression group (78.0%) than in the non-compression group (70.2%) (p = 0.011). Overall accuracy of staging in compression and non-compression groups was 84.7% and 77.3%, respectively.

CONCLUSION

Our results demonstrate that digital rectal compression performed immediately after prostate biopsy to reduce intraprostatic hemorrhage improves the accuracy for detection of PCa using MRI.

Comparison of body-array MRI and Partin tables for predicting extracapsular prostate cancer

Objective:

The objective of this article is to evaluate the performance of magnetic resonance imaging (MRI) and Partin tables at predicting extracapsular disease (ECD) in men with prostate cancer.

Patients and methods:

We identified all patients who had a radical prostatectomy at our institution in 2008. MRI and Partin predictions of ECD were compared with the histopathological stage. Oncological outcome at one year was assessed by biochemical recurrence (BCR) (prostate-specific antigen (PSA) ≥ 0.4 ng/dl followed by another rise).

Results:

Staging and follow-up data were available for 69 of the 80 patients (86%) who had had radical prostatectomy. Thirty-five of 69 patients had a body-array MRI scan. MRI predicted ECD (≥ rT3) with a sensitivity of 41% and specificity of 69%. Partin tables (> 50% risk ECD) had a sensitivity of 81% and specificity of 54%. Of the 35 patients who had an MRI scan, 22 (63%) had ECD and nine (26%) had BCR. Of the 34 men who were not staged with an MRI, only 10 (29%) had ECD and four (12%) had BCR.

Conclusion:

MRI performed no better than Partin tables at predicting ECD. Furthermore, patients who did not have an MRI, because of favourable prognostic clinical variables, had a low risk of ECD and BCR. We question the role of body-array MRI for staging prostate cancer and recognise an urgent need for prospective evaluation of multiparametric MRI.

Impact of delay after biopsy and post-biopsy haemorrhage on prostate cancer tumour detection using multi-parametric MRI: a multi-reader study

AIM

To assess impact of haemorrhage and delay after biopsy on prostate tumour detection using multi-parametric (MP) magnetic resonance imaging (MRI) assessment.

MATERIALS AND METHODS

Forty-four patients underwent prostate MRI at 1.5 T using a pelvic phased-array coil, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging, before prostatectomy. Three radiologists independently reviewed images during four sessions [T2WI, DWI, DCE, and all parameters combined (MP-MRI)] to assess for tumour in each sextant. In a separate session, readers reviewed T1WI to score the extent of haemorrhage per sextant. Accuracy was assessed using logistic regression for correlated data.

RESULTS

There was no significant difference in accuracy between readers for any session (p ≥ 0.166), and results were averaged across the three readers for remaining comparisons. Accuracy was significantly greater for MP-MRI than for any parameter alone (p ≤ 0.020). For T2WI alone, there was a trend toward decreased sensitivity in sextants with extensive haemorrhage (p = 0.072). However, accuracy, sensitivity, and specificity were otherwise similar for sextants with and without extensive haemorrhage for all sessions (p = 0.192-0.934). No session showed a significant improvement in accuracy, sensitivity, or specificity in cases with delay after biopsy of over 4 weeks compared with shorter delay.

CONCLUSION

Extensive haemorrhage and short delay after biopsy did not negatively impact accuracy for tumour detection using MP-MRI. Further studies using MP-MRI protocols and interpretation schemes from other institutions are required to confirm these observations.

Value of the hemorrhage exclusion sign on T1-weighted prostate MR images for the detection of prostate cancer

PURPOSE

To retrospectively determine the prevalence and positive predictive value (PPV) of the hemorrhage exclusion sign on T1-weighted magnetic resonance (MR) images in conjunction with findings on T2-weighted images in the detection of prostate cancer, with use of whole-mount step-section pathologic specimens from prostatectomy as the reference standard.

MATERIALS AND METHODS

The institutional review board approved this retrospective study, which was compliant with HIPAA, and the requirement to obtain informed consent was waived. Two hundred ninety-two patients with biopsy-proved prostate cancer underwent endorectal MR imaging followed by prostatectomy. The hemorrhage exclusion sign was defined as the presence of a well-defined area of low signal intensity surrounded by areas of high signal intensity on T1-weighted images. Two readers independently assessed the presence and extent of postbiopsy changes and the hemorrhage exclusion sign. The presence of a corresponding area of homogeneous low signal intensity on T2-weighted images was also recorded. The prevalence and PPV of the hemorrhage exclusion sign were calculated.

RESULTS

Readers 1 and 2 found postbiopsy changes in the peripheral zone in 184 (63%) and 189 (64.7%) of the 292 patients, respectively. In these patients, the hemorrhage exclusion sign was observed in 39 of 184 patients (21.2%) by reader 1 and 36 of 189 patients (19.0%) by reader 2. A corresponding area of homogeneous low signal intensity was seen on T2-weighted images in the same location as the hemorrhage exclusion sign in 23 of 39 patients (59%) by reader 1 and 19 of 36 patients (53%) by reader 2. The PPV of the hemorrhage exclusion sign alone was 56% (22 of 39 patients) for reader 1 and 50% (18 of 36 patients) for reader 2 but increased to 96% (22 of 23 patients) and 95% (18 of 19 patients) when the sign was identified in an area of homogeneous low signal intensity on T2-weighted images.

CONCLUSION

Postbiopsy change is a known pitfall in the interpretation of T2-weighted images. The authors have shown that a potential benefit of postbiopsy change is the presence of excluded hemorrhage, which, in conjunction with a corresponding area of homogeneous low signal intensity at T2-weighted imaging, is highly accurate for cancer identification.

Automatic conformal prescription of very selective saturation bands for in vivo 1H-MRSI of the prostate

An important step in the implementation of three-dimensional in vivo proton magnetic resonance spectroscopic imaging ((1)H-MRSI) of the prostate is the placement of spatial saturation pulses around the region of interest (ROI) for the removal of unwanted contaminating signals from peripheral tissue. The present study demonstrates the use of a technique called conformal voxel magnetic resonance spectroscopy (CV-MRS). This method automates the placement, orientation, timing and flip angle of very selective saturation (VSS) pulses around an irregularly-shaped, user-defined ROI. The method employs a user adjustable number of automatically positioned VSS pulses (20 used in the present study) which null the signal from periprostatic lipids while closely conforming the shape of the excitation voxel to the shape of the prostate. A standard endorectal coil in combination with a torso-phased array coil was used for all in vivo prostate studies. Three-dimensional in vivo prostate (1)H-MRSI data were obtained using the proposed semi-automated CV-MRS technique, and compared with a standard point resolved spectroscopy (PRESS) technique at TE = 130 ms using manual placement of saturation pulses. The in vivo prostate (1)H-MRSI data collected from 12 healthy subjects using the CV-MRS method showed significantly reduced lipid contamination throughout the prostate, and reduced baseline distortions. On average there was a 50 ± 17% (range 12% - 68%) reduction in lipids throughout the prostate. A voxel-by-voxel benchmark test of over 850 voxels showed that there were 63% more peaks fitted using the LCModel when using a Cramer-Rao Lower Bound (CRLB) cut-off of 40% when using the optimized conformal voxel technique in comparison to the manual placement approach. The evaluation of this CV-MRS technique has demonstrated the potential for easy automation of the graphical prescription of saturation bands for use in (1)H-MRSI.

Imaging in prostate cancer staging: present role and future perspectives

Despite recent improvements in detection and treatment, prostate cancer continues to be the most common malignancy and the second leading cause of cancer-related mortality. Thus, although survival rate continues to improve, prostate cancer remains a compelling medical health problem. The major goal of prostate cancer imaging in the next decade will be more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information in order to plan the most appropriate therapeutic strategy. No consensus exists regarding the use of imaging for evaluating primary prostate cancer. However, conventional and functional imaging are expanding their role in detection and local staging and, moreover, functional imaging is becoming of great importance in oncologic management and monitoring of therapy response. This review presents a multidisciplinary perspective on the role of conventional and functional imaging methods in prostate cancer staging.

Prospective evaluation of 3-T MRI performed before initial transrectal ultrasound-guided prostate biopsy in patients with high prostate-specific antigen and no previous biopsy

OBJECTIVE

The purpose of our study was to prospectively evaluate whether MRI before an initial transrectal ultrasound-guided biopsy contributed to detection of prostate cancer in patients with high prostate-specific antigen (PSA) level and no previous biopsy.

SUBJECTS AND METHODS

Men with an abnormal digital rectal examination or high PSA level were enrolled in this prospective randomized study. Participants were randomly allocated into two groups; the MRI group underwent 3-T MRI and then a transrectal ultrasound-guided biopsy with knowledge of the cancer location. The non-MRI group did not undergo MRI before transrectal ultrasound-guided biopsy. The cancer detection rate and positive core rate were obtained to compare the MRI and non-MRI groups.

RESULTS

The MRI and non-MRI groups contained 44 and 41 patients, respectively. There was no significant difference between the two groups with respect to age, PSA, and prostate volume. The MRI group (13/44, 29.5%) had a significantly higher cancer detection rate than the non-MRI group (4/41, 9.8%) (p = 0.03). The MRI group (52/527, 9.9%) had a significantly higher positive core rate than the non-MRI group (11/432, 2.5%) (p = 0.00). Regarding cancer detection rate and positive core rate, odds ratios were 3.9 (95% CI, 1.1-13.1) and 4.2 (95% CI, 2.2-8.1), respectively.

CONCLUSION

In patients with PSA level and no previous biopsy, 3-T MRI that is performed before transrectal ultrasound-guided biopsy may contribute to the detection of prostate cancer.

Prostate cancer: multiparametric MR imaging for detection, localization, and staging

This review presents the current state of the art regarding multiparametric magnetic resonance (MR) imaging of prostate cancer. Technical requirements and clinical indications for the use of multiparametric MR imaging in detection, localization, characterization, staging, biopsy guidance, and active surveillance of prostate cancer are discussed. Although reported accuracies of the separate and combined multiparametric MR imaging techniques vary for diverse clinical prostate cancer indications, multiparametric MR imaging of the prostate has shown promising results and may be of additional value in prostate cancer localization and local staging. Consensus on which technical approaches (field strengths, sequences, use of an endorectal coil) and combination of multiparametric MR imaging techniques should be used for specific clinical indications remains a challenge. Because guidelines are currently lacking, suggestions for a general minimal protocol for multiparametric MR imaging of the prostate based on the literature and the authors' experience are presented. Computer programs that allow evaluation of the various components of a multiparametric MR imaging examination in one view should be developed. In this way, an integrated interpretation of anatomic and functional MR imaging techniques in a multiparametric MR imaging examination is possible. Education and experience of specialist radiologists are essential for correct interpretation of multiparametric prostate MR imaging findings. Supportive techniques, such as computer-aided diagnosis are needed to obtain a fast, cost-effective, easy, and more reproducible prostate cancer diagnosis out of more and more complex multiparametric MR imaging data.

Effect of Prostate Biopsy Hemorrhage on MRDW and MRS Imaging

Purpose

To retrospectively evaluate the effect of post-prostate-biopsy hemorrhage on the interpretation of magnetic resonance diffusion-weighted (MRDW) and magnetic resonance spectroscopic (MRS) imaging in the detection of prostate cancer. We also investigated the optimal timing for magnetic resonance examination after prostate biopsy.

Materials and Methods

We reviewed the records of 135 men. All patients underwent prostate magnetic resonance imaging (MRI). The prostate was divided into eight regions according to the biopsy site. Subsequently, we measured hemorrhage on apparent diffusion coefficient (ADC) values and (choline+creatinine)/citrate ([Cho+Cr]/Cit) ratios in the same regions on the MRI. We investigated the effect of hemorrhage at ADC values and (Cho+Cr)/Cit ratios on MRI and the relationship between prostate biopsy results and MRI findings.

Results

The mean patient age was 68.7 years and the mean time between biopsy and MRI was 23.5 days. The total hemorrhagic score demonstrated no significant associations with intervals from biopsy to MRI. Higher hemorrhagic scores were associated with higher ADC values, prostate cancer, and noncancer groups, respectively (p<0.001). ADC values were lower in tumors than in normal tissue (p<0.001), and ADC values were inversely correlated with tumor Gleason score in biopsy cores (p<0.001). However, (Cho+Cr)/Cit ratios did not exhibit any association with prostate biopsy results and hemorrhage.

Conclusions

Hemorrhage had no significant associations with the interval from biopsy to MRI. ADC values may help to detect prostate cancer and predict the aggressiveness of cancer; however, it is important to consider the bias effect of hemorrhage on the interpretation of MRDW imaging given that hemorrhage affects ADC values.

Advancements in MR imaging of the prostate: from diagnosis to interventions

Prostate cancer is the most frequently diagnosed cancer in males and the second leading cause of cancer-related death in men. Assessment of prostate cancer can be divided into detection, localization, and staging; accurate assessment is a prerequisite for optimal clinical management and therapy selection. Magnetic resonance (MR) imaging has been shown to be of particular help in localization and staging of prostate cancer. Traditional prostate MR imaging has been based on morphologic imaging with standard T1-weighted and T2-weighted sequences, which has limited accuracy. Recent advances include additional functional and physiologic MR imaging techniques (diffusion-weighted imaging, MR spectroscopy, and perfusion imaging), which allow extension of the obtainable information beyond anatomic assessment. Multiparametric MR imaging provides the highest accuracy in diagnosis and staging of prostate cancer. In addition, improvements in MR imaging hardware and software (3-T vs 1.5-T imaging) continue to improve spatial and temporal resolution and the signal-to-noise ratio of MR imaging examinations. Another recent advancement in the field is MR imaging guidance for targeted prostate biopsy, which is an alternative to the current standard of transrectal ultrasonography-guided systematic biopsy.

Preoperative nomograms incorporating magnetic resonance imaging and spectroscopy for prediction of insignificant prostate cancer

Study Type--Prognosis (case series). Level of Evidence 4. What's known on the subject? And what does the study add? Nomograms are available that combine clinical and biopsy findings to predict the probability of pathologically insignificant prostate cancer in patients with clinically low-risk disease. Based on data from patients with Gleason score 6, clinical stage ≤ T2a and PSA <20 ng/ml, our group developed the first nomogram models for predicting insignificant prostate cancer that incorporated clinical data, detailed biopsy data and findings from MRI or MRI/MRSI (BJU Int. 2007;99(4):786-93). When tested retrospectively, these MR models performed significantly better than standard clinical models with and without detailed biopsy data. We prospectively validated the previously published MR-based nomogram models in a population of patients with Gleason score 6, clinical stage ≤ T2a and PSA <10 ng/ml. Based on data from this same population, we also developed two new models for predicting insignificant prostate cancer that combine MR findings and clinical data without detailed biopsy data. Upon initial testing, the new MR models performed significantly better than a clinical model lacking detailed biopsy data.

OBJECTIVES

• To validate previously published nomograms for predicting insignificant prostate cancer (PCa) that incorporate clinical data, percentage of biopsy cores positive (%BC+) and magnetic resonance imaging (MRI) or MRI/MR spectroscopic imaging (MRSI) results. • We also designed new nomogram models incorporating magnetic resonance results and clinical data without detailed biopsy data. Nomograms for predicting insignificant PCa can help physicians counsel patients with clinically low-risk disease who are choosing between active surveillance and definitive therapy.

PATIENTS AND METHODS

• In total, 181 low-risk PCa patients (clinical stage T1c-T2a, prostate-specific antigen level <10 ng/mL, biopsy Gleason score of 6) had MRI/MRSI before surgery. • For MRI and MRI/MRSI, the probability of insignificant PCa was recorded prospectively and independently by two radiologists on a scale from 0 (definitely insignificant) to 3 (definitely significant PCa). • Insignificant PCa was defined on surgical pathology. • There were four models incorporating MRI or MRI/MRSI and clinical data with and without %BC+ that were compared with a base clinical model without %BC and a more comprehensive clinical model with %BC+. Prediction accuracy was assessed using areas under receiver-operator characteristic curves.

RESULTS

• At pathology, 27% of patients had insignificant PCa, and the Gleason score was upgraded in 56.4% of patients. • For both readers, all magnetic resonance models performed significantly better than the base clinical model (P ≤ 0.05 for all) and similarly to the more comprehensive clinical model.

CONCLUSIONS

• Existing models incorporating magnetic resonance data, clinical data and %BC+ for predicting the probability of insignificant PCa were validated. • All MR-inclusive models performed significantly better than the base clinical model.

Fast T2*-weighted MRI of the prostate at 3 Tesla

PURPOSE

To describe a rapid T2*-weighted (T2*W), three-dimensional (3D) echo planar imaging (EPI) sequence and its application in mapping local magnetic susceptibility variations in 3 Tesla (T) prostate MRI. To compare the sensitivity of T2*W EPI with routinely used T1-weighted turbo-spin echo sequence (T1W TSE) in detecting hemorrhage and the implications on sequences sensitive to field inhomogeneities such as MR spectroscopy (MRS).

MATERIALS AND METHODS

B(0) susceptibility weighted mapping was performed using a 3D EPI sequence featuring a 2D spatial excitation pulse with gradients of spiral k-space trajectory. A series of 11 subjects were imaged using 3T MRI and combination endorectal (ER) and six-channel phased array cardiac coils. T1W TSE and T2*W EPI sequences were analyzed quantitatively for hemorrhage contrast. Point resolved spectroscopy (PRESS MRS) was performed and data quality was analyzed.

RESULTS

Two types of susceptibility variation were identified: hemorrhagic and nonhemorrhagic T2*W-positive areas. Post-biopsy hemorrhage lesions showed on average five times greater contrast on the T2*W images than T1W TSE images. Six nonhemorrhage regions of severe susceptibility artifact were apparent on the T2*W images that were not seen on standard T1W or T2W images. All nonhemorrhagic susceptibility artifact regions demonstrated compromised spectral quality on 3D MRS.

CONCLUSION

The fast T2*W EPI sequence identifies hemorrhagic and nonhemorrhagic areas of susceptibility variation that may be helpful in prostate MRI planning at 3.0T.

The predictability of T3 disease in staging MRI following prostate biopsy decreases in patients with high initial PSA and Gleason score

To obtain improved accuracy in predicting extracapsular extension (ECE) and seminal vesicle invasion (SVI), we evaluated the variables affecting the predictability of staging magnetic resonance imaging (MRI, phased-array coil) and estimated their impact on accuracy between preoperative MRI staging and histological outcome. A total of 121 patients with localized or locally advanced prostate cancer who underwent robotic radical prostatectomy (RALP) were included. Following transrectal biopsy, all enrolled patients had undergone MRI for staging work-up. After RALP, only 43.8% (53/121) of the patients were matched with the MRI predicted stage. Compared to the matched group in the prediction of ECE, the unmatched group had significantly higher initial prostate-specific antigen (PSA, 12.8 ng ml⁻¹ versus 8.1 ng ml⁻¹, P = 0.048). In the prediction of SVI, initial PSA (8.1 ng ml⁻¹ versus 17.3 ng ml⁻¹, P = 0.009) and biopsy Gleason score (6.5 versus 7.6, P = 0.035) were significantly higher in the unmatched group. When applying clinical cutoffs of initial PSA of 10 and 20 ng ml⁻¹, the accuracy of MRI in the prediction of ECE was decreased in the group with PSA over 20 ng ml⁻¹ (75.6, 64.5 and 37.5%, P = 0.01), and this group had significantly decreased accuracy of MRI in the prediction of SVI (91.5, 77.4 and 37.5%, P<0.01). Applying the clinical cutoff of a Gleason score of 7, the accuracy of MRI in the prediction of SVI was decreased in the higher Gleason score group (93.9, 82.1 and 62.9%, P = 0.01). Thus, for these patient groups, to obtain margin negativity during radical prostatectomy, operative findings, rather than post-biopsy MRI images, may provide substantial information, implying a clinical advantage in conducting MRI before prostate biopsy.

Imaging in prostate cancer

Prostate cancer is the most common malignancy in men, in general. Most patients diagnosed with prostate cancer have localized disease confined to the prostate. A small percentage of patients with aggressive tumors will progress to develop local, extracapsular tumor extension and distant metastases. The aim of prostate cancer management is to identify and treat those patients with aggressive disease before they develop locally advanced or metastatic disease, and to avoid overtreating indolent tumors, which are unlikely to be life threatening. Imaging has been shown to be valuable in local staging of prostate cancer and as an aid to the management of clinically significant disease. In this article, we discuss the different established imaging modalities and emerging techniques for prostate cancer imaging in patients with clinically localized disease who may be suitable for radical treatment.

The sensitivity of [11C]choline PET/CT to localize prostate cancer depends on the tumor configuration

PURPOSE

To evaluate the dependency of the sensitivity of [(11)C]choline positron emission tomography/computed tomography (PET/CT) for detecting and localizing primary prostate cancer (PCa) on tumor configuration in the histologic specimen.

EXPERIMENTAL DESIGN

Forty-three patients with biopsy-proven PCa were included. They underwent radical prostatectomy within 31 days after [(11)C]choline PET/CT. The transaxial image slices and the histologic specimens were analyzed by comparing the respective slices. Maximum standardized uptake values (SUV(max)) were calculated in each segment and correlated with histopathology. The tumor configuration in the histologic specimen was grouped as: I, unifocal; II, multifocal; III, rind-like shaped; IV, size <5 mm. Data analysis included the investigation of detection of PCa by SUV(max), the assessment of the influence of potential contributing factors on tumor prediction, and the evaluation of whether SUV could discriminate cancer tissue from benign prostate hyperplasia (BPH), prostatitis, HGPIN (high-grade prostate intraepithelial neoplasm), or normal prostate tissue. General estimation equation models were used for statistical analysis.

RESULTS

Tumor configuration in histology was classified as I in 21 patients, as II in 9, as III in 5, and as IV in 8. The prostate segment involved by cancer is identified in 79% of the patients. SUV(max) was located in the same side of the prostate in 95% of patients. Tumor configuration was the only factor significantly negatively influencing tumor prediction (P < 0.001). PCa-SUV(max) (median SUV(max) = 4.9) was not significantly different from BPH-SUV (median SUV(max) = 4.5) and prostatitis-SUV (median SUV(max) = 3.9), P = 0.102 and P = 0.054, respectively.

CONCLUSIONS

The detection and localization of PCa in the prostate with [(11)C]choline PET/CT is impaired by tumor configuration. Additionally, in our patient population, PCa tissue could not be distinguished from benign pathologies in the prostate.

Incremental value of T2-weighted and diffusion-weighted MRI for prediction of biochemical recurrence after radical prostatectomy in clinically localized prostate cancer

BACKGROUND

For men with clinically localized prostate cancer and candidates to receive radical prostatectomy (RP) a main concern is a cancer recurrence after treatment. Although previous studies have demonstrated the diagnostic utility of diffusion-weighted imaging (DWI) for prostate cancer, the prognostic value of pretreatment DWI has not been investigated yet.

PURPOSE

To investigate the incremental value of MRI-based T staging using DWI and T2-weighted imaging (T2WI) as compared with the clinical parameters in prediction of biochemical recurrence (BCR) after RP for clinically localized prostate cancer.

MATERIAL AND METHODS

Sixty MR examinations, obtained before RP between April 2002 and March 2009, were retrospectively reviewed using T2WI alone, DWI alone, or T2WI + DWI for T staging according to the 2002 American Joint Committee on Cancer guidelines. The relationship between MRI stage and BCR was evaluated using Kaplan-Meier survival estimates. Multivariate analysis and receiver operating characteristics (ROC) curve analysis were used to investigate the incremental value over the standard clinical variables in prediction of BCR.

RESULTS

As of August 2009, 12 (20%) patients had BCR. Based on T2WI + DWI, both T3a (compared to OC disease) and T2 (compared to T1c) showed significantly higher BCR rates (p=0.047 and 0.025, respectively). Multivariate analysis and area under ROC curve analysis confirmed the additional value of MRI staging to the conventional clinical variables in prediction of BCR.

CONCLUSION

The combination of T2WI and DWI on performing pretreatment MRI helped predict BCR after RP in clinically localized prostate cancer.

The effects of the period between biopsy and diffusion-weighted magnetic resonance imaging on cancer staging in localized prostate cancer

OBJECTIVES

to investigate whether there are any differences between preoperative magnetic resonance imaging (MRI) and the final pathology results, based on the time between biopsy and preoperative MRI, as there are reports recommending ≥ 3 weeks after a prostate biopsy, primarily because haemorrhaging interferes with the interpretation of MRI.

PATIENTS AND METHODS

between December 2007 and December 2008, we retrospectively analysed 69 consecutive patients who had biopsy-confirmed prostate cancer. The inclusion criteria for the study were a history of MRI investigation (combined T2-weighted and diffusion-weighted MRI) and robot-assisted laparoscopic radical prostatectomy. The exclusion criteria included an MRI investigation-to-surgery interval of ≥ 1 week, a biopsy having been taken in another hospital, or other than 12 biopsy cores. The amount of haemorrhaging, number of haemorrhaging sites, and the location of the cancer were determined. For this, the prostate was divided into 12 segments which anatomically corresponded to the sites where the 12 core biopsies were taken. Each haemorrhagic prostate segment was scored according to its diameter. Pathology results were reviewed in the same manner. Finally, we assessed any discordance between the sets of results according to the period between the biopsy and the MRI. The association between the MRI and pathology results, in relation to the period between the biopsy and MRI, was plotted and tested using Pearson's correlation coefficient.

RESULTS

five of the 69 patients were excluded because they had a biopsy at another hospital, 12 were excluded because the period between the MRI and the surgery was >7 days. Suspected prostate haemorrhage was detected in 49 of 52 (94%) patients who had MRI. There was a significantly negative correlation with the period between biopsy and MRI (coefficient - 0.285, P= 0.041). There were no significant differences in cancer localization between MRI and pathology results according to the period between the biopsy and MRI (coefficient 0.028, P= 0.874). The rate of matching between MRI results and pathology results was 74%.

CONCLUSIONS

we found no significant differences in cancer localization between MRI and final pathology according to the period between the biopsy and MRI. Because of this finding, we do not recommend deferring MRI for the purpose of more accurate cancer staging.

[Imaging diagnostics of the prostate]

Prostate cancer is the most common malignancy of men with approximately 32,000 new cases of prostate cancer in Germany and approximately 11,000 men who would die of the disease each year. For early diagnosis of prostate cancer PSA testing is used, whereas at present screening cannot be recommended due to the lack of confirmed medical and economic benefits. Regarding the imaging modalities, ultrasound of the prostate, currently performed in combination with elastography and histoscanning, magnetic resonance imaging of the prostate in combination with endorectal coils and positron emission tomography combined with computed tomography (PET-CT) are the methods of choice. Using these methods benign prostatitis can be differentiated from prostate cancer and staging of the tumor can be accomplished. On the other hand using these imaging methods it is possible to define the dominant intraprostatic lesion with different sensitivities and specificities, which is important for minimally invasive therapeutic strategies.

Diffusion-weighted magnetic resonance imaging in patients with unilateral prostate cancer on extended prostate biopsy: predictive accuracy of laterality and implications for hemi-ablative therapy

PURPOSE

We evaluated the ability of extended prostate biopsy to detect unilateral prostate cancer and assessed the incremental diagnostic benefit of diffusion-weighted magnetic resonance imaging to predict unilateral prostate cancer.

MATERIALS AND METHODS

A total of 130 patients with prostate cancer detected by extended pattern prostate biopsy underwent magnetic resonance imaging before radical prostatectomy. Tumor laterality on extended prostate biopsy was compared with the corresponding lobe on the radical prostatectomy specimen. In patients with unilateral prostate cancer on biopsy we calculated the probability of a tumor in the contralateral lobe on magnetic resonance images and calculated area under the receiver operating characteristics curve. We compared the diagnostic accuracy of combined T2-weighted and diffusion-weighted magnetic resonance images to that of T2-weighted magnetic resonance images alone.

RESULTS

Of the 130 patients 88 (67.7%) had unilateral disease on extended prostate biopsy. Radical prostatectomy pathology showed that 19% of these patients had unilateral disease but 81% had bilateral disease. Area under the receiver operating characteristics curve of combined diffusion-weighted and T2-weighted magnetic resonance imaging was greater than that of T2-weighted magnetic resonance imaging alone (0.814, 95% CI 0.716-0.889 vs 0.510, 95% CI 0.401-0.618). T2-weighted plus diffusion-weighted magnetic resonance imaging had significantly higher sensitivity (84.1% vs 61.9%, p = 0.003) and specificity (72.0% vs 36.0%, p = 0.004) to predict cancer in the contralateral lobe than T2-weighted magnetic resonance alone.

CONCLUSIONS

Extended prostate biopsy cannot accurately determine prostate cancer unilaterality. Diffusion-weighted magnetic resonance combined with T2-weighted magnetic resonance imaging has an incremental diagnostic benefit to predict unilateral prostate cancer.

[Active surveillance for prostate cancer: usefulness of endorectal MR at 1.5 Tesla with pelvic phased array coil in detecting significant tumors]

PURPOSE

To describe and assess MRI signs of significant tumor in a series of patients who all underwent radical prostatectomy and also fulfilled criteria to choose active surveillance according to French "SurAcaP" protocol.

PATIENTS AND METHODS

The clinical reports of 681 consecutive patients operated on for prostate cancer between 2002 and 2007 were reviewed retrospectively. All patients had endorectal MR (1.5 Tesla) with pelvic phased array coil. (1.5 T erMR PPA). Sixty-one patients (8.9%) fulfilled "SurAcaP" protocol criteria. Preoperative data (MR+core biopsy) were assessed by comparison to whole-mount step section pathology.

RESULTS

85.3% of the 61 patients entering SurAcaP protocol had significant tumor at pathology. (Non Organ Confined Disease (Non OCD)=8.2%, Gleason sum score>6=39.2%). A new exclusion criterion has been assessed: T3MRI±NPS>1 as a predictor tool of significant tumor. ("T3MRI±NPS>1"=Non OCD at MR±number of positive sextants involved in tumor at MR and/or Core Biopsy > to 1). Sensitivity, specificity, PPV, NPV of the criterion "T3MRI±NPS>1" in predicting significant tumor were, respectively: 77%, 33%, 86%, 20%. Adding this criterion to other criteria of the "SurAcaP" protocol could allow the exclusion of all Non OCD, and a decrease in Gleason sum Score>6 rates (20%).

CONCLUSION

Endorectal MR at 1.5 Tesla with pelvic-phased array coil should be considered when selecting patients for active surveillance in the management of prostate cancer. A criterion based upon MR and core biopsy findings, called "T3MR±NSP>1" may represent an exclusion citeria due to its ability to predict significant tumor.

Choline PET/CT for prostate cancer: main clinical applications

Several studies investigated the potential roles of imaging modalities in prostate cancer patients for the evaluation of intra-prostatic disease, stage and restage. However no precise guidelines exist about the use of imaging modalities, in particular about the role of PET/CT hybrid imaging. Considering the results of the literature and our experience, we tried to summarize the main applications of choline positron emission tomography (PET) in prostate cancer patients. The use of choline PET/CT for initial diagnosis and staging is not recommended as a first-line method. Instead the main and important application of choline PET/CT is represented by the restaging of the disease in case of biochemical relapse for the detection of lymph node and distant recurrence. In particular choline PET/CT could play a crucial role as first diagnostic procedure in prostate cancer patients who show a fast growing Prostate Specific Antigen (PSA) kinetics.

Is endorectal coil necessary for the staging of clinically localized prostate cancer? Comparison of non-endorectal versus endorectal MR imaging

PURPOSE

The goal of this study was to compare the diagnostic use and safety of endorectal coil (ERC) MRI with those of phased-array coil MRI.

METHODS

We retrospectively included 91 consecutive patients who had undergone 1.5-T MRI with ERC or with phased-array coil MRI before radical prostatectomy at our institution. We compared 47 patients' phased-array coil MRI and 44 patients' ERC-MRI with histologic findings. We also evaluated adverse events following the MRI procedure.

RESULTS

The serum PSA levels ranged from 2.85 to 33.51 ng/mL (10.72 ± 1.9), and the median Gleason score was 7 (range 4-9). The mean interval between diagnostic prostate biopsy and staging MRI was 18.4 days (range 2-37). In assessing organ-confined disease, extracapsular extension and seminal vesicle invasion by MRI, there were no significant differences between ERC-MR group and phased-array coil MR group. The AUC values were 0.671 (95% CI 0.530-0.813) for ERC-MR and 0.657 (95% CI 0.503-0.811) for phased-array coil MR. No significant differences were found between the two groups (p = 0.24). Five patients (11.4%) developed rectal complications after ERC-MRI. However, no complications were found in phased-array coil MRI group.

CONCLUSIONS

In terms of diagnostic accuracy and comfort of patients, the use of ERC-MRI did not significantly improve the staging of prostate cancer and presented several complications. Therefore, phased-array coil MRI is a better alternative considering comorbidity.

Prostate MRI and 3D MR spectroscopy: how we do it

OBJECTIVE

This review is a primer on the technical aspects of performing a high-quality MRI and MR spectroscopic imaging examination of the prostate.

CONCLUSION

MRI and MR spectroscopic imaging are useful tools in the localization, staging, and functional assessment of prostate cancer. Performing a high-quality MR spectroscopic examination requires understanding of the technical aspects and limitations of spectral acquisition, postprocessing techniques, and spectral evaluation.

Modalities for imaging of prostate cancer

Prostate cancer is the second most common cause of cancer deaths among males in the United States. Prostate screening by digital rectal examination and prostate-specific antigen has shifted the diagnosis of prostate cancer to lower grade, organ confined disease, adding to overdetection and overtreatment of prostate cancer. The new challenge is in differentiating clinically relevant tumors from ones that may otherwise never have become evident if not for screening. The rapid evolution of imaging modalities and the synthesis of anatomic, functional, and molecular data allow for improved detection and characterization of prostate cancer. However, the appropriate use of imaging is difficult to define, as many controversial studies regarding each of the modalities and their utilities can be found in the literature. Clinical practice patterns have been slow to adopt many of these advances as a result. This review discusses the more established imaging techniques, including Ultrasonography, Magnetic Resonance Imaging, MR Spectroscopy, Computed Tomography, and Positron Emission Tomography. We also review several promising techniques on the horizon, including Dynamic Contrast-Enhanced MRI, Diffuse-Weighted Imaging, Superparamagnetic Nanoparticles, and Radionuclide Scintigraphy.

Multidisciplinary functional MR imaging for prostate cancer

Various functional magnetic resonance (MR) imaging techniques are used for evaluating prostate cancer including diffusion-weighted imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy. These techniques provide unique information that is helpful to differentiate prostate cancer from non-cancerous tissue and have been proven to improve the diagnostic performance of MRI not only for cancer detection, but also for staging, post-treatment monitoring, and guiding prostate biopsies. However, each functional MR imaging technique also has inherent challenges. Therefore, in order to make accurate diagnoses, it is important to comprehensively understand their advantages and limitations, histologic background related with image findings, and their clinical relevance for evaluating prostate cancer. This article will review the basic principles and clinical significance of functional MR imaging for evaluating prostate cancer.

Peripheral zone prostate cancer. Pre-treatment evaluation with MR and 3D ¹H MR spectroscopic imaging: correlation with pathologic findings

The purpose of this study was to retrospectively characterize benign and malignant prostate peripheral zone tissue by using endorectal MRI and 3D ¹H MRS. Fifty-two men with untreated biopsy-proven prostate cancer underwent combined endorectal MRI and MRSI. Whole-mount step-section histopathologic analysis constituted the reference standard. Biopsy correctly detected 74 locations; MRI correctly detected 72 locations; MRS correctly detected 72 locations; MRI + MRS correctly detected 78 locations. Cohen's test showed that biopsy had a lower degree of agreement with histology than MRI + MRS combined. The ratio of [(Cho + Cr)]/Cit correlates with the pathologic Gleason score. The addition of 3D¹H MRSI to MRI can improve diagnosis of prostate cancer contributing indirectly to improve local staging. In addition, the correlation between metabolic 3D¹H MRSI data with pathological Gleason grade may offer a non-invasive means to better predict prostate cancer aggressiveness.

Imaging localized prostate cancer: current approaches and new developments

OBJECTIVE

Prostate cancer is the most common noncutaneous malignancy among men in the Western world. Imaging has recently become more important in the diagnosis, local staging, and treatment follow-up of prostate cancer. In this article, we review conventional and functional imaging methods as well as targeted imaging approaches with novel tracers used in the diagnosis and staging of prostate cancer.

CONCLUSION

Although prostate cancer is the second leading cause of cancer death in men, imaging of localized prostate cancer remains limited. Recent developments in imaging technologies, particularly MRI and PET, may lead to significant improvements in lesion detection and staging.

Prediction of prostate cancer recurrence using magnetic resonance imaging and molecular profiles

PURPOSE

To evaluate whether pretreatment magnetic resonance imaging (MRI)/MR spectroscopic imaging (MRSI) findings and molecular markers in surgical specimens correlate with each other and with pretreatment clinical variables (biopsy Gleason score, clinical stage, and prostate-specific antigen level) and whether they contribute incremental value in predicting prostate cancer recurrence.

EXPERIMENTAL DESIGN

Eighty-eight prostate cancer patients underwent MRI/MRSI before radical prostatectomy; imaging findings were scored on a scale of 1 to 7 (no tumor seen-lymph node metastasis). Ki-67, phospho-Akt, and androgen receptor expression in surgical specimens were assessed by immunohistochemistry. To examine correlations between markers and imaging scores, Spearman's correlation was used. To test whether markers and imaging scores differed by clinical stage or Gleason score, Wilcoxon's rank sum test was used. To examine time to recurrence, the methods of Kaplan-Meier were used. Cox proportional hazards models were built and their concordance indices (C-indices) were calculated to evaluate prediction of recurrence.

RESULTS

All markers correlated moderately strongly with MRI/MRSI score (all correlation coefficients >0.5). Markers and MRI/MRSI score were strongly associated with clinical stage and biopsy Gleason score (P < 0.01 for all). At last follow-up, 27 patients had recurrence. C-indices for MRI/MRSI score and all markers were associated with time to recurrence and ranged from 0.78 to 0.89. A Cox model combining all clinical predictors had a C-index of 0.89; the C-index increased to 0.95 when MRI/MRSI score was added and to 0.97 when markers were also added.

CONCLUSIONS

MRI/MRSI findings and molecular markers correlated well with each other and contributed incremental value to clinical variables in predicting prostate cancer recurrence.

New horizons in prostate cancer imaging

Prostate cancer is the most common non-cutaneous malignancy among American men. Imaging has recently become more important in detection of prostate cancer since screening techniques such as digital rectal examination (DRE), prostate specific and transrectal ultrasound guided biopsy have considerable limitations in diagnosis and localization of prostate cancer. In this manuscript, we reviewed conventional, functional and targeted imaging modalities used in diagnosis and local staging of prostate cancer with exquisite images.

Correlation of MR imaging and MR spectroscopic imaging findings with Ki-67, phospho-Akt, and androgen receptor expression in prostate cancer

PURPOSE

To retrospectively assess whether magnetic resonance (MR) imaging and MR spectroscopic imaging and selected molecular markers correlate with each other and with clinically insignificant and significant prostate cancer (PCa), as defined at surgical pathologic analysis.

MATERIALS AND METHODS

The institutional review board approved this HIPAA-compliant study and waived informed consent. Eighty-nine men (mean age, 63 years; range, 46-79 years) with biopsy-proved PCa underwent combined endorectal MR imaging and MR spectroscopic imaging before radical prostatectomy. Suspicion of clinically insignificant PCa was retrospectively and separately recorded for MR imaging and combined MR imaging and MR spectroscopic imaging by using a scale of 0-3. Clinically insignificant PCa was pathologically defined as organ-confined cancer of 0.5 cm(3) or less without poorly differentiated elements. Prostatectomy specimens underwent immunohistochemical analysis for three molecular markers: Ki-67, phospho-Akt (pAkt), and androgen receptor (AR). To examine differences in marker levels for clinically insignificant and significant cancer, a Wilcoxon rank sum test was used. To examine correlations between marker levels and MR imaging or combined MR imaging and MR spectroscopic imaging scores, the Spearman correlation was used.

RESULTS

Twenty-one (24%) patients had clinically insignificant and 68 (76%) had clinically significant PCa at surgical pathologic review. All markers were significantly correlated with MR imaging and combined MR imaging and MR spectroscopic imaging findings (all correlation coefficients >0.5). In differentiating clinically insignificant from clinically significant PCa, areas under the receiver operating characteristic curves for Ki-67, AR, pAkt, MR imaging, and combined MR imaging and MR spectroscopic imaging were 0.75, 0.78, 0.80, 0.85, and 0.91, respectively.

CONCLUSION

The use of pretreatment MR imaging or combined MR imaging and MR spectroscopic imaging and molecular marker analyses of biopsy samples could facilitate better treatment selection.

SUPPLEMENTAL MATERIAL

http://radiology.rsnajnls.org/cgi/content/full/250/3/803/DC1.

Imaging techniques for prostate cancer: implications for focal therapy

The multifocal nature of prostate cancer has necessitated whole-gland therapy in the past; however, since the widespread use of PSA screening, patients frequently present with less-advanced disease. Many men with localized disease wish to avoid the adverse effects of whole-gland therapy; therefore, focal therapy for prostate cancer is being considered as a treatment option. For focal treatment to be viable, accurate imaging is required for diagnosis, staging, and monitoring of treatment. Developments in MRI and PET have brought more attention to prostate imaging and the possibility of improving the accuracy of focal therapy. In this Review, we discuss the advantages and disadvantages of conventional methods for imaging the prostate, new developments for targeted imaging, and the possible role of image-guided biopsy and therapy for localized prostate cancer.

Espectroscopia por ressonância magnética no diagnóstico do câncer de próstata: experiência inicial

OBJETIVO: Demonstrar a experiência na implantação de um protocolo de espectroscopia por ressonância magnética do 1H tridimensional (3D 1H MRSI), disponível comercialmente, aplicando-o em pacientes com suspeita de neoplasia prostática e com diagnóstico estabelecido de tumor prostático. MATERIAIS E MÉTODOS: Estudo realizado de forma prospectiva, em 41 pacientes com idades entre 51 e 80 anos (média de 67 anos). Dois grupos foram formados: pacientes com uma ou mais biópsias negativas para câncer e antígeno prostático específico elevado (grupo A) e pacientes com câncer confirmado por biópsia (grupo B). Procurou-se, a partir dos resultados da ressonância magnética e espectroscopia por ressonância magnética, determinar a área-alvo (grupo A) ou a extensão do câncer conhecido (grupo B). RESULTADOS: No diagnóstico de câncer de próstata a espectroscopia por ressonância magnética apresentou especificidade abaixo da descrita pela literatura, cerca de 47%. Já para o estadiamento do tumor diagnosticado, houve correspondência com a literatura. CONCLUSÃO: A implantação e padronização da espectroscopia por ressonância magnética permitiram a obtenção de informações importantes para o diagnóstico presuntivo da existência de câncer de próstata, combinando as imagens por ressonância magnética com os dados metabólicos da espectroscopia por ressonância magnética.