Localizing prostate cancer in the presence of postbiopsy changes on MR images: role of proton MR spectroscopic imaging

What You Need to Know Before Reading Multiparametric MRI for Prostate Cancer

OBJECTIVE. Multiparametric MRI (mpMRI) has become the main imaging modality for the detection, localization, and local staging of prostate cancer over the past decade. For radiologists to achieve consistent and reproducible reporting of prostate mpMRI, a comprehensive evaluation of the gland including detailed knowledge of anatomy, pathology, and clinical data is required. This article familiarizes radiologists with common pitfalls and conditions that affect mpMRI performance during readouts. CONCLUSION. Consistent, accurate, and reproducible reporting of prostate mpMRI is vital. Additionally, radiologists should be aware of common diagnostic pitfalls that can hinder mpMRI performance.

Nuclear magnetic resonance spectroscopy of human body fluids and in vivo magnetic resonance spectroscopy: Potential role in the diagnosis and management of prostate cancer

Prostate cancer is the most common solid organ cancer in men, and the second most common cause of male cancer-related mortality. It has few effective therapies, and is difficult to diagnose accurately. Prostate-specific antigen (PSA), which is currently the most effective diagnostic tool available, cannot reliably discriminate between different pathologies, and in fact only around 30% of patients found to have elevated levels of PSA are subsequently confirmed to actually have prostate cancer. As such, there is a desperate need for more reliable diagnostic tools that will allow the early detection of prostate cancer so that the appropriate interventions can be applied. Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance spectroscopy (MRS) are 2 high throughput, noninvasive analytical procedures that have the potential to enable differentiation of prostate cancer from other pathologies using metabolomics, by focusing specifically on certain metabolites which are associated with the development of prostate cancer cells and its progression. The value that this type of approach has for the early detection, diagnosis, prognosis, and personalized treatment of prostate cancer is becoming increasingly apparent. Recent years have seen many promising developments in the fields of NMR spectroscopy and MRS, with improvements having been made to hardware as well as to techniques associated with the acquisition, processing, and analysis of related data. This review focuses firstly on proton NMR spectroscopy of blood serum, urine, and expressed prostatic secretions in vitro, and then on 1- and 2-dimensional proton MRS of the prostate in vivo. Major advances in these fields and methodological principles of data collection, acquisition, processing, and analysis are described along with some discussion of related challenges, before prospects that proton MRS has for future improvements to the clinical management of prostate cancer are considered.

Does the Time Interval from Biopsy to Radical Prostatectomy Affect the Postoperative Oncologic Outcomes in Korean Men?

BACKGROUND

Prostate cancer (PC) is the second most common type of cancer in men worldwide and the fifth most common cancer among Korean men. Although most PCs grow slowly, it is unclear whether a longer time interval from diagnosis to treatment causes worse outcomes. This study aimed to investigate whether the time interval from diagnosis to radical prostatectomy (RP) in men with clinically localized PC affects postoperative oncologic outcomes.

METHODS

We retrospectively analyzed data of 427 men who underwent RP for localized PC between January 2005 and June 2016. The patients were divided into two groups based on the cutoff median time interval (100 days) from biopsy to surgery. The associations between time interval from biopsy to surgery (< 100 vs. ≥ 100 days) and adverse pathologic outcomes such as positive surgical margin, pathologic upgrading, and upstaging were evaluated. Biochemical recurrence (BCR)-free survival rates were analyzed and compared based on the time interval from biopsy to surgery.

RESULTS

Pathologic upgrading of Gleason score in surgical specimens was more frequent in the longer time interval group and showed marginal significance (38.8% vs. 30.0%; P = 0.057). Based on multivariable analysis, an association was observed between time interval from biopsy to surgery and pathologic upgrading (odds ratio, 2.211; 95% confidence interval [CI], 1.342-3.645; P = 0.002). BCR-free survival did not differ based on time interval from biopsy to surgery, and significant association was not observed between time interval from biopsy to surgery and BCR on multivariable analysis (hazard ratio, 1.285; 95% CI, 0.795-2.077; P = 0.305).

CONCLUSION

Time interval ≥ 100 days from biopsy to RP in clinically localized PC increased the risk of pathologic upgrading but did not affect long-term BCR-free survival rates in Korean men.

Multiparametric MR imaging of peripheral zone prostate cancer: effect of postbiopsy hemorrhage on cancer detection according to Gleason score and tumour volume

OBJECTIVE

To evaluate effect of postbiopsy hemorrhage on detection of peripheral zone (PZ) prostate cancer by multiparametric MR imaging according to Gleason score and tumor volume.

METHODS

This retrospective study included 54 biopsy-proven prostate cancer patients (median age, 67.0 years) who underwent multiparametric MR imaging. Two independent readers evaluated each sextant of the PZ using the PI-RADS v2. One reader recorded the presence or absence of hemorrhage per sextant on T₁ weighted MR images. Areas under the receiver operating characteristic curves (AUCs) were used to evaluate cancer detection accuracy.

RESULTS

Postbiopsy hemorrhage was noted in 122 (37.7%) of 324 sextants of all patients. There was no significant difference in the AUC for detection of cancer with Gleason score ≥3 + 4 or volume ≥0.5 ml between sextants with and without hemorrhage (with hemorrhage, reader 1, 0.83 for Gleason score ≥3 + 4, 0.84 for tumor volume ≥0.5 ml; reader 2, 0.74 for Gleason score ≥3 + 4, 0.77 for tumor volume ≥0.5 ml; without hemorrhage, reader 1, 0.86 for Gleason score ≥3 + 4, 0.88 for tumor volume ≥0.5 ml; reader 2, 0.79 for Gleason score ≥3 + 4, 0.83 for tumor volume ≥0.5 ml; p > 0.2 for all).

CONCLUSION

Postbiopsy hemorrhage did not negatively affect the detection of clinically significant PZ prostate cancer on multiparametric MR imaging. Advances in knowledge: Under influence of postbiopsy hemorrhage, multiparametric MR can be useful for the detection of clinically significant PZ prostate cancer.

Can robot-assisted laparoscopic radical prostatectomy (RALP) be performed very soon after biopsy?

PURPOSE

To identify the perioperative and oncological impact of different intervals between biopsy and robot-assisted laparoscopic radical prostatectomy (RALP) for localized prostate cancer.

METHODS

All consecutive patients with localized prostate cancer who underwent RALP with primary curative intent in January 2008-July 2014 in a large tertiary hospital were enrolled in this retrospective cohort study. The patients were divided into groups according to whether the biopsy-RALP interval was ≤2, ≤4, ≤6, or >6 weeks. Estimated blood loss and operating room time were surrogates for surgical difficulty. Surgical margin status and continence at the 1 year were surrogates for surgical efficacy. Biochemical recurrence (BCR) was defined as two consecutive postoperative prostate serum antigen values of ≥0.2 ng/ml.

RESULTS

Of the 1446 enrolled patients, the biopsy-RALP interval was ≤2, ≤4, ≤6, and >6 weeks in 145 (10 %), 728 (50.3 %), 1124 (77.7 %), and 322 (22.3 %) patients, respectively. The >6 week group had a significantly longer mean operation time than the ≤2, ≤4, and ≤6 week groups. The groups did not differ significantly in terms of estimated blood loss or surgical margin status. Kaplan-Meier analysis showed that interval did not significantly affect postoperative BCR-free survival. Multivariable Cox proportional hazards model analysis showed that interval duration was not an independent predictor of BCR (≤2 vs. >2 weeks, HR = 0.859, p = 0.474; ≤4 vs. >4 weeks, HR = 1.029, p = 0.842; ≤6 vs. >6 weeks, HR = 0.84, p = 0.368).

CONCLUSION

Performing RALP within 2, 4, or 6 weeks of biopsy does not appear to adversely influence surgical difficulty or efficacy or oncological outcomes.

Practical aspects of prostate MRI: hardware and software considerations, protocols, and patient preparation

The use of multiparametric MRI scans for the evaluation of men with prostate cancer has increased dramatically and is likely to continue expanding as new developments come to practice. However, it has not yet gained the same level of acceptance of other imaging tests. Partly, this is because of the use of suboptimal protocols, lack of standardization, and inadequate patient preparation. In this manuscript, we describe several practical aspects of prostate MRI that may facilitate the implementation of new prostate imaging programs or the expansion of existing ones.

Prostatic Bleeding after Prostatic Biopsy Effects Oncological Outcomes with Laparoscopic Radical Prostatectomy

BACKGROUND

We vigorously reviewed patients' operation record who had adhesion of the Denonvilliers' fascia and found out most of these patients had prostatic bleeding after prostatic gland biopsies. We examined the magnitude of prostatic bleeding and frequency after biopsies and the relationship with oncological outcomes.

MATERIALS AND METHODS

A total of 285 patients were selected for the final analyses. Inclusion criteria were as follows: receiving MRI three weeks after biopsiesand laparoscopic radical prostatectomy within 300 days after biopsy. We divided the patients into two groups with (group A) or without (group B) prostatic bleeding. We examined the magnitude of prostatic bleeding after biopsies and the relationship with operation time (OT), positive surgical margin (PSM), biochemical recurrence (BCR) and other factors. Furthermore, we created a logistic-regression model to derive a propensity score for prostatic bleeding after biopsies, which included all patient and hospital characteristics as well as selected interaction terms, and we examined the relationship with PSM and BCR.

RESULTS

In all patients, the OT in the group B was shorter than the group A (p < 0.001). Prostatic bleeding was associated with PSM (p=0.000) and BCR (p=0.036). In this propensity-matched cohort, 11 of 116 patients in the group B had PSM as compared with 36 of 116 patients from group A (match-adjusted odds ratio, 4.30; 95%CI confidence interval, 2.06 to 8.96; P=0.000). In addition, eight of 116 patients in group B encountered BCR, as compared with 18 of 116 patients in group A (match-adjusted odds ratio, 2.48; 95%CI, 1.03 to 5.96; P=0.042). Kaplan-Meier analysis in the propensity matching cohort showed a significant biochemical recurrence-free survival advantage for being free of prostate bleeding after biopsies.

CONCLUSIONS

Our findings in the present cohort should help equip surgeons to pay attention to careful excision especially for those who experienced deferred prostatic bleeding.

Value of preoperative 3T multiparametric MRI for surgical margin status in patients with prostate cancer

PURPOSE

To examine the value of preoperative multiparametric magnetic resonance imaging (MRI) as a predictor of surgical margin (SM) status in patients with prostate cancer (PC).

MATERIALS AND METHODS

The Institutional Review Board approved this retrospective study; the requirement for informed consent was waived. Fifty-six male patients with histologically proven PC underwent preoperative 3T multiparametric MRI including high b value (0, 2000 s/mm(2) ) diffusion-weighted imaging. In each patient, clinical data, such as biopsy Gleason score and D'Amico clinical risk score, and multiparametric MRI findings, such as tumor location, tumor size, tumor extension in the apical or proximal region, tumor apparent diffusion coefficient (ADC), and the presence or absence of MRI findings of extracapsular extension (ECE) were evaluated. Statistical evaluations included the Fisher's exact test, χ(2) test, Mann-Whitney U-test, and logistic regression analysis.

RESULTS

On histopathological evaluation, 15 patients (27%) were SM-positive (SMP group), and 41 (73%) were SM-negative (SMN group). The tumor ADC was significantly lower in the SMP group than in the SMN group (P = 0.001). The frequency of tumor extension in the apex or base and suspected ECE on MRI were significantly higher in the SMP group than in the SMN group (P = 0.037 and 0.011, respectively). On multivariate analysis, tumor ADC was the only predictor of SM status in PC (P = 0.003).

CONCLUSION

PC with positive SM was characterized by tumor extension in the apical and proximal regions, lower tumor ADC, and tumors with positive MRI findings of ECE, compared to tumors with negative SM. J. Magn. Reson. Imaging 2016;44:584-593.

T2* relaxation time in the detection and assessment of aggressiveness of peripheral zone cancer in comparison with diffusion-weighted imaging

AIM

To investigate the feasibility of T2* relaxation time for distinguishing benign from malignant regions, as well as tumour aggressiveness, within the peripheral zone (PZ) of the prostate in comparison with diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

Fifty-eight patients with prostate cancer underwent 3 T magnetic resonance imaging using multi-echo T2* and DWI (maximum b-value, 2000 s/mm(2)). Parametric maps were obtained for apparent diffusion coefficient (ADC) and T2* values. Two radiologists reviewed these maps and measured ADC and T2* values in sextants positive for cancer at biopsy. Data were analysed using mixed-model analysis of variance and receiver operating characteristic curves.

RESULTS

Ninety-three sextants exhibited a Gleason score of 6; 59 exhibited a Gleason score of 7 or 8. The T2* value was significantly lower in cancerous sextants than in the benign PZ (48.69+0.60 versus 74.14+0.56, p<0.001), as well as in cancerous sextants with higher rather than lower Gleason scores (43.18+0.89 versus 52.18+0.55, p<0.001). The T2* value showed significantly greater specificity for differentiating cancerous sextants from benign PZ than ADC (93.1% versus 89.7%, p<0.001), with equal sensitivity (82.8% versus 81%, p>0.05). The T2* value exhibited significantly greater sensitivity and specificity for differentiating sextants with low- and high-grade cancer than ADC (79.6% versus 64.5% and 81.4% versus 72.9%, respectively; p<0.05). The T2* value had a significantly greater area under the receiver operating characteristic curve for differentiating sextants with low- and high-grade cancer than ADC (0.77 versus 0.71, p<0.01).

CONCLUSION

Preliminary findings suggest that the T2* relaxation time has increased diagnostic value compared with DWI in prostate PZ cancer assessment.

Evolution of multi-parametric MRI quantitative parameters following transrectal ultrasound-guided biopsy of the prostate

BACKGROUND

To determine the evolution of prostatic multi-parametric magnetic resonance imaging (mp-MRI) signal following transrectal ultrasound (TRUS)-guided biopsy.

METHODS

Local ethical permission and informed written consent was obtained from all the participants (n=14, aged 43-69, mean 64 years). Patients with a clinical suspicion of prostate cancer (PSA range 2.2-11.7, mean 6.2) and a negative (PIRAD 1-2/5) pre-biopsy mp-MRI (pre-contrast T1, T2, diffusion-weighted and dynamic-contrast-enhanced MRI) who underwent 10-core TRUS-guided biopsy were recruited for additional mp-MRI examinations performed at 1, 2 and 6 months post biopsy. We quantified mp-MRI peripheral zone (PZ) and transition zone (TZ) normalized T2 signal intensity (nT2-SI); T1 relaxation time (T10); diffusion-weighted MRI, apparent diffusion coefficient (ADC); dynamic contrast-enhanced MRI, maximum enhancement (ME); slope of enhancement (SoE) and area-under-the-contrast-enhancement-curve at 120 s (AUC120). Significant changes in mp-MRI parameters were identified by analysis of variance with Dunnett's post testing.

RESULTS

Diffuse signal changes were observed post-biopsy throughout the PZ. No significant signal change occurred following biopsy within the TZ. Left and right PZ mean nT2-SI (left PZ: 5.73, 5.16, 4.90 and 5.12; right PZ: 5.80, 5.10, 4.84 and 5.05 at pre-biopsy, 1, 2 and 6 months post biopsy, respectively) and mean T10 (left PZ: 1.02, 0.67, 0.78, 0.85; right PZ: 1.29, 0.64, 0.78, 0.87 at pre-biopsy, 1, 2 and 6 months post biopsy, respectively) were reduced significantly (P<0.05) from pre-biopsy values for up to 6 months post biopsy. Significant changes (P<0.05) of PZ-ME and AUC120 were observed at 1 month but resolved by 2 months post biopsy. PZ ADC did not change significantly following biopsy (P=0.23-1.0). There was no significant change of any TZ mp-MRI parameter at any time point following biopsy (P=0.1-1.0).

CONCLUSIONS

Significant PZ (but not TZ) T2 signal changes persist up to 6 months post biopsy, whereas PZ and TZ ADC is not significantly altered as early as 1 month post biopsy. Caution must be exercised when interpreting T1- and T2-weighted imaging early post biopsy, whereas ADC images are more likely to maintain clinical efficacy.

Computer-Aided Detection and diagnosis for prostate cancer based on mono and multi-parametric MRI: a review

Prostate cancer is the second most diagnosed cancer of men all over the world. In the last few decades, new imaging techniques based on Magnetic Resonance Imaging (MRI) have been developed to improve diagnosis. In practise, diagnosis can be affected by multiple factors such as observer variability and visibility and complexity of the lesions. In this regard, computer-aided detection and computer-aided diagnosis systems have been designed to help radiologists in their clinical practice. Research on computer-aided systems specifically focused for prostate cancer is a young technology and has been part of a dynamic field of research for the last 10 years. This survey aims to provide a comprehensive review of the state-of-the-art in this lapse of time, focusing on the different stages composing the work-flow of a computer-aided system. We also provide a comparison between studies and a discussion about the potential avenues for future research. In addition, this paper presents a new public online dataset which is made available to the research community with the aim of providing a common evaluation framework to overcome some of the current limitations identified in this survey.

The optimal timing of post-prostate biopsy magnetic resonance imaging to guide nerve-sparing surgery

The goal of our study was to evaluate the impact of the interval between prostate biopsy and magnetic resonance imaging (MRI) on the accuracy of simple tumor localization, which is essential information that enables nerve-sparing surgery. We also sought to determine the optimal timing of a post-biopsy MRI. A total of 184 patients who had undergone MRI before radical prostatectomy at an institution without a predetermined schedule for MRI after a prostate biopsy were enrolled. The mean interval from the biopsy to the MRI was 30.8 ± 18.6 days. The accuracy of the MRI for simplified tumor location (right, left, bilateral and none) was 44.6%. In the group with discordant pathologic and MRI findings, the most common reason recorded was ‘MRI predicted a unilateral lesion, but pathology revealed bilateral lesions’ (58.3%), followed by ‘MRI predicted no lesion, but pathology revealed the presence of a lesion’ (32.0%). Multivariable analysis showed that the discordant group had a shorter interval (25.0 ± 14.3 vs 38.1 ± 20.6 days, P < 0.01) preceding the MRI and a higher rate of hemorrhage as observed by MRI (80.4% vs 54.8%, P < 0.01) in comparison with the accordant group. In receiver operating characteristics analysis, the area under the curve of the MRI interval in accurate prediction of the tumor location was 0.707 (P < 0.001). At the MRI interval's cutoff of 28.5 days, the sensitivity was 73.2% and the specificity was 63.7%. When the MRI was performed within 28 days, the accumulated accuracy was only 26.1% (23/88); however, when it was performed after 28 days, the reversely accumulated accuracy was 61.5% (59/96). These data support a waiting period of at least 4 weeks after a biopsy before performing an MRI for the purposes of surgical refinement.

High b value (2,000 s/mm2) diffusion-weighted magnetic resonance imaging in prostate cancer at 3 Tesla: comparison with 1,000 s/mm2 for tumor conspicuity and discrimination of aggressiveness

Objective

The objective of our study was to investigate tumor conspicuity and the discrimination potential for tumor aggressiveness on diffusion-weighted magnetic resonance imaging (DW-MRI) with high b value at 3-T.

Materials and Methods

The institutional review board approved this study and waived the requirement for informed consent. A total of 50 patients with prostate cancer (69 cancer foci; 48 in the PZ, 20 in the TZ, and one in whole prostate) who underwent multiparametric prostate MRI including DW-MRI (b values: 0, 1000 s/mm² and 0, 2000 s/mm²) on a 3-T system were included. Lesion conspicuity score (LCS) using visual assessment (1 = invisible for surrounding normal site; 2 = slightly high intensity; 3 = moderately high; and 4 = very high) and tumor-normal signal intensity ratio (TNR) were assessed, and apparent diffusion coefficient (ADC, ×10⁻³ mm²/s) of the tumor regions and normal regions were measured.

Results

Mean LCS and TNR at 0, 2000 s/mm² was significantly higher than those at 0, 1000 s/mm² (p<0.001 for both). In addition, ADC at both 0, 1000 and 0, 2000 s/mm² was found to distinguish intermediate or high risk cancer with Gleason score ≥7 from low risk cancer with Gleason score ≤6 (p<0.001 for both). Furthermore, ADC of tumor regions correlated with Gleason score at both 0, 1000 s/mm² (ρ = −0.602; p<0.001) and 0, 2000 s/mm² (ρ = −0.645; p<0.001).

Conclusions

For tumor conspicuity and characterization of prostate cancer on DW-MRI of 3-T MRI, b = 0, 2000 s/mm² is more useful than b = 0, 1000 s/mm².

Endorectal coil MRI and MR-spectroscopic imaging in patients with elevated serum prostate specific antigen with negative trus transrectal ultrasound guided biopsy

Background:

The aim of this study was to see the efficacy of endorectal coil MRI and MR spectroscopic imaging in patients with elevated serum PSA and negative transrectal ultrasonography (TRUS)-guided biopsy.

Materials and Methods:

This study was conducted on 87 patients presented with: • Elevated prostatic specific antigen levels >5 ng/ml • Symptoms and signs of prostatic carcinoma • Patients with negative TRUS-guided biopsy • Suspicious lesion on TRU. All the patients were subjected to TRUS and followed by TRUS-guided biopsy of the lesion identified on endorectal coil MRI and MR-Spectroscopy. TRUS-guided biopsy of prostate was done with a Siemens Sonoline Adana Scanner. The scanning was performed by mechanical probe 5-7.5 MHz.

Results:

Out of 87 patients, 43 (49.4%) had hypointense lesion, 11 (12.6%) had hyperintense lesion. Out of 87 patients, MR-spectroscopy showed peak choline-creatine in 74 patients. Normal citrate peak was seen in 13 patients. Patients who had choline-creatine peak, among them 28 (37.8%) had peak in left peripheral zone, 23 (31.1%) had peak in the right peripheral zone, 2 (2.7%) had peak in the central zone, 17 had (23%) peak bilaterally. Four patients (5.4%) had peaks in right and central zones. The difference was statistically significant (P < 0.001).

Conclusion:

Prostatic biopsy directed with endorectal coil MRI and MR-spectroscopic imaging findings in patients with elevated serum PSA and prior negative biopsy, improves the early diagnosis of prostatic carcinoma and accurate localization of prostate cancer within the gland.

Advanced MRI in malignant neoplasms of the uterus

Conventional magnetic resonance imaging (MRI) such as T1-weighted and T2-weighted images of the female pelvis provide morphological information with excellent tissue contrast, which reflects the pathology of malignant diseases of the uterus. Owing to the recent improvement in hardware and software, in combination with extensive research in imaging techniques, not only MRI at higher magnetic field was facilitated, but also insight into tumor pathophysiology was provided. These methods include diffusion-weighted imaging (DWI), dynamic contrast-enhanced MRI (DCE-MRI) with pharmacokinetic analysis, and MR spectroscopy (MRS). The application of these techniques is expanding from the brain to the body because information on the tissue microenvironment and cytoarchitecture is helpful for lesion characterization, evaluation of treatment response after chemotherapy or radiation, differentiating posttherapeutic changes from residual active tumor, and for detecting recurrent cancer. These techniques may provide clues to optimize the treatment of patients with malignant diseases of the uterus. In the first half of this article we provide an overview of the technical aspects of MRI of the female pelvis, especially focusing on the state-of-the-art techniques such as 3 T MRI, DCE-MRI, DWI, etc. For the latter half we review the clinical aspects of these newly developed techniques, focusing on how these techniques are applicable, what has been revealed with respect to clinical impact, and the remaining problems.

Multiparametric magnetic resonance imaging findings in men with low-risk prostate cancer followed using active surveillance

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Up to 35% of men on active surveillance (AS) for clinically localized prostate cancer will experience biopsy reclassification during follow-up. Currently, annual prostate biopsy is recommended in AS programmes. Multiparametric MRI has shown promise in identifying men at risk for immediate reclassification at the time of entry into AS; however, the MRI characteristics of men already enrolled in AS who may be at low risk for disease reclassification have not been fully described. In the present study, we describe the MRI findings of a cohort of men enrolled within AS, with extended follow-up. Among these men, multiparametric MRI demonstrated excellent specificity (0.974) and negative predictive value (0.897) for the detection of pathological index lesions (determined on serial biopsies). These results suggest that men enrolled in AS with a non-suspicious MRI are unlikely to harbour an index cancerous lesion.

OBJECTIVE

To assess the performance of multiparametric magnetic resonance imaging (MRI) in identifying pathological-index (path-index) lesions, defined as cancer present in the same prostate sextant in two separate surveillance biopsies, in men followed within an active surveillance (AS) programme for low-risk prostate cancer (CaP) with extended follow-up.

MATERIALS AND METHODS

A total of 50 men, representing >215 person-years of follow-up in an AS programme, who were referred for prostate MRI were randomly chosen to have their images reviewed by a radiologist with expertise in prostate MRI, who was blinded to biopsy results. Index lesions on MRI were defined as a single suspicious lesion ≥10 mm or >2 lesions in a given prostate sextant. Lesions on MRI were considered suspicious if ≥2 abnormal parameters co-registered anatomically. Path-index lesions were defined as cancer present in a given prostate sextant on two separate biopsy sessions. Sensitivity and specificity were calculated to test the performance of MRI for identifying path-index lesions. Clinical and pathological features were compared between men with and without a MRI-index lesion.

RESULTS

A total of 31 path-index and 13 MRI-index lesions were detected in 22 and 10 patients, respectively. Multiparametric MRI demonstrated excellent specificity and negative predictive value (0.974 and 0.897, respectively) for the detection of path-index lesions. Sensitivity (0.19) and positive predictive value (0.46) were considerably lower. Patients with an index lesion on MRI were younger and less likely to have met the 'Epstein' criteria for very low-risk CaP. Compared with men without an MRI lesion, a significant increase in biopsy reclassification was noted for men with a MRI lesion (40 vs 12.5%, P = 0.04).

CONCLUSIONS

A non-suspicious MRI was highly correlated with a lack of path-index lesions in an AS population. Multiparametric MRI may be useful in both the selection and monitoring of patients undergoing AS.

Diffusion-weighted magnetic resonance imaging of the prostate: improved robustness with stretched exponential modeling

PURPOSE

This study aimed to compare the intraclass correlation coefficients of parameters estimated with stretched exponential and biexponential diffusion models of in vivo diffusion-weighted magnetic resonance imaging (MRI) of the prostate.

METHODS

After the institutional review board issued a waiver of informed consent for this Health Insurance Portability and Accountability Act-compliant study, 25 patients with biopsy-proven prostate cancer underwent 3T endorectal MRI and diffusion-weighted MRI of the prostate at 10 b values (0, 45, 75, 105, 150, 225, 300, 600, 900, and 1200 s/mm). The full set of b values was collected twice within a single acquisition. Intraclass correlation coefficients were calculated for intra-acquisition variability. From the biexponential model, the quantitative parameters diffusion coefficient (D), perfusion coefficient (D*), and perfusion fraction (f) were estimated. From the stretched exponential model, the quantitative parameters Kohlrausch decay constant (DK) and alpha (α) were estimated.

RESULTS

For the 25 patient data sets, the average intraclass correlation coefficients for DK and α were 95.8%, and 64.1%, respectively, whereas those for D, D*, and f were 84.4%, 25.3%, and 41.3%, respectively.

CONCLUSIONS

The stretched exponential diffusion model captures the nonlinear effects of intravoxel incoherent motion in the prostate. The parameters derived from this model are more reliable and reproducible than the parameters derived from the standard, widely used biexponential diffusion/perfusion model.

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.

Prostate cancer: multiparametric MRI for index lesion localization--a multiple-reader study

OBJECTIVE

The purpose of this study was to evaluate the utility of multiparametric MRI in localization of the index lesion of prostate cancer.

MATERIALS AND METHODS

Fifty-one patients who underwent 3-T MRI of the prostate with a pelvic phased-array coil that included T2-weighted, diffusion-weighted, and dynamic contrast-enhanced sequences before prostatectomy were included. Six radiologists assessed all images to identify the lesion most suspicious of being the index lesion, which was localized to one of 18 regions. A uropathologist using the same 18-region scheme reviewed the prostatectomy slides to localize the index lesion. MRI performance was assessed by requiring either an exact match or an approximate match (discrepancy of up to one region) between the MRI and pathologic findings in terms of assigned region.

RESULTS

The pathologist identified an index lesion in 49 of 51 patients. In exact-match analysis, the average sensitivity was 60.2% (range, 51.0-63.3%), and the average positive predictive value (PPV) was 65.3% (range, 61.2-69.4%). In approximate-match analysis, the average sensitivity was 75.9% (range, 65.3-69.6%), and the average PPV was 82.6% (range, 79.2-91.4%). The sensitivity was higher for index lesions with a Gleason score greater than 6 in exact-match (74.8% vs 15.3%, p<0.001) and approximate-match (88.7% vs 36.1%, p=<0.001) analyses and for index lesions measuring at least 1 cm in approximate-match analysis (80.3% vs 58.3%, p=0.016). In exact-match analysis, 30.0%, 44.9%, and 79.1% of abnormalities found with one, two, and three MRI parameters represented the index lesion (p<0.001).

CONCLUSION

The sensitivity and PPV of multiparametric MRI for index lesion localization were moderate, although they improved in the setting of more aggressive pathologic features and a greater number of abnormal MRI parameters, respectively.

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.

3.0 T multiparametric prostate MRI using pelvic phased-array coil: utility for tumor detection prior to biopsy

OBJECTIVE

To evaluate the role of multiparametric magnetic resonance imaging (MRI) performed in men without a biopsy-proven diagnosis of prostate cancer using follow-up biopsy as the reference standard.

MATERIALS AND METHODS

Forty-two patients without biopsy-proven cancer and who underwent MRI were included. In all patients, MRI was performed at 3T using a pelvic phased-array coil and included T2-weighted imaging, diffusion-weighted imaging, and dynamic contrast-enhanced imaging. Thirteen had undergone no previous biopsy, and 29 had undergone at least 1 previous negative biopsy. All patients underwent prostate biopsy following MRI. Two fellowship-trained radiologists in consensus reviewed all cases and categorized each lobe as positive or negative for tumor. These interpretations were correlated with findings on post-MRI biopsy.

RESULTS

Follow-up biopsy was positive in 23 lobes in 15 patients (36% of study cohort). On a per-patient basis, MRI had a sensitivity of 100%, specificity of 74%, positive predictive value (PPV) of 68%, and negative predictive value (NPV) of 100%. On a per-lobe basis, MRI had a sensitivity of 65%, specificity of 84%, PPV of 60%, and NPV of 86%. There was a nearly significant association between Gleason score and tumor detection on MRI (P = 0.072).

CONCLUSIONS

In our sample, MRI had 100% sensitivity in predicting the presence of tumor on subsequent biopsy on a per-patient basis, suggesting a possible role for MRI in selecting patients with an elevated prostatic specific antigen (PSA) to undergo prostate biopsy. However, MRI had weaker specificity for prediction of a subsequent positive biopsy, as well as weaker sensitivity for tumor on a per-lobe basis, indicating that in patients with a positive MRI result, tissue sampling remains necessary for confirmation of the diagnosis as well as for treatment planning.

[Complications and nerve preservation in prostatectomy according to the time interval from diagnostic biopsy]

OBJECTIVES

To summarize the available evidence on complications and bilateral nerve preservation in radical prostatectomy in patients according to the time interval from diagnostic biopsy (more or less than six weeks).

MATERIAL AND METHODS

Relevant studies were identified by using structured and specific search strategies for each of the databases consulted, without limitations. The methodological quality of each of the studies included was evaluated and the data were extracted independently.

RESULTS

For open radical prostatectomy, two of the studies concluded that a time interval of less than 4 or 6 weeks between prostate biopsy and surgery had no influence on the postsurgical complications rate or on nerve preservation during surgery. For laparoscopic robotic-assisted radical prostatectomy, the study included concluded that performing this type of intervention in an interval of less than 4 or 6 weeks after diagnostic biopsy was associated with a higher risk of postsurgical complications. However, all these studies had major methodological limitations.

CONCLUSIONS

The time interval between diagnostic biopsy and open surgery has no influence on the complications rate or nerve preservations. In contrast, an interval of less than 4 weeks between diagnostic biopsy and laparoscopic surgery is associated with a higher risk of surgical complications.

MR imaging of treated prostate cancer

Many management options are available to patients with newly diagnosed prostate cancer. Magnetic resonance (MR) imaging plays an important role in initial staging of prostate cancer, but it also aids in tumor detection when there is clinical or biochemical suspicion of residual or recurrent disease after treatment. The purpose of this review is to describe the normal appearances of the prostatic region after different kinds of treatment for prostate cancer and to discuss how these appearances differ from those of recurrent and residual disease. Several MR imaging techniques used in evaluating patients with prostate cancer are described, including conventional MR imaging sequences (mainly T1- and T2-weighted sequences), MR spectroscopic imaging, diffusion-weighted imaging, and dynamic contrast agent-enhanced MR imaging. Clinical considerations, together with the different approaches for interpreting serum prostate-specific antigen values in the posttreatment setting, are also presented. All forms of treatment alter the MR imaging features of the prostatic region to a greater or lesser extent, and it is important to be able to recognize expected posttreatment appearances and distinguish them from the features of recurrent or residual cancer to aid subsequent clinical management.

Prostate cancer: utility of fusion of T2-weighted and high b-value diffusion-weighted images for peripheral zone tumor detection and localization

PURPOSE

To retrospectively assess the utility of fusion of T2-weighted images (T2WI) and high b-value diffusion-weighted images (DWI) for prostate cancer detection and localization.

MATERIALS AND METHODS

In this IRB-approved HIPAA-compliant study, 42 patients with prostate cancer underwent MRI including multiplanar T2WI and axial DWI before prostatectomy. Two independent radiologists first assessed multiplanar T2WI and axial DWI(b-1000) images and recorded whether tumor was present in each sextant. Axial T2WI was then fused with axial DWI(b-1000) images, and the radiologists re-evaluated each sextant for tumor. Accuracy was compared using generalized estimating equations based on a binary logistic regression model.

RESULTS

The accuracy, sensitivity, specificity, PPV, and NPV for tumor detection on a sextant-basis using separate and fused image sets was 65.1%, 50.8%, 78.0%, 67.8%, and 63.6% and 71.0%, 60.8%, 80.3%, 73.7%, and 69.3%, respectively, for reader 1, and 54.0%, 42.5%, 64.4%, 52.0%, and 55.2%, and 61.1%, 56.7%, 65.2%, 59.6%, and 62.3%, respectively, for reader 2. The improvements in accuracy, sensitivity, and NPV using fused images were statistically significant for both readers, as was the improvement in PPV for reader 2 (P ranging from <0.0001 to 0.041). With either separate or fused images, there was greater sensitivity for tumors of higher grade or larger size (P ranging from <0.001 to 0.099).

CONCLUSION

Fusion of T2WI and high b-value DWI resulted in significant improvements in sensitivity and accuracy for tumor detection on a sextant-basis, with similar specificity.

Prostate cancer detection in patients with total serum prostate-specific antigen levels of 4-10 ng/mL: diagnostic efficacy of diffusion-weighted imaging, dynamic contrast-enhanced MRI, and T2-weighted imaging

OBJECTIVE

The purpose of this study is to evaluate the utility of T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI) for detecting prostate cancer in patients with total serum prostate-specific antigen (PSA) levels of 4-10 ng/mL, which is referred to as the "gray zone."

MATERIALS AND METHODS

Fifty patients with gray-zone PSA levels underwent MRI before biopsy. According to the sites of biopsy, the prostate was divided into eight regions on MRI scans. These regions were evaluated individually for the following features: detectability of prostate cancer on per-region and per-patient bases, and relationship between tumor size and positive or negative MRI findings for tumor detection.

RESULTS

On a per-region basis, the sensitivity and specificity of tumor detection were 36% and 97% for T2-weighted imaging, 43% and 95% for DCE-MRI, 38% and 96% for DWI, and 53% and 93% for the combined method of MRI, respectively. The sensitivity of combined MRI to detect tumor was significantly higher than those of the individual methods (p < 0.001 to p = 0.001). Tumor size was significantly larger in regions with positive MRI findings than in regions with negative MRI findings (p = 0.004). On a per-patient basis, sensitivity and specificity of combined MRI to detect prostate cancer were 83% and 80%, respectively.

CONCLUSION

Combined T2-weighted imaging, DWI, and DCE-MRI findings appear to be potentially useful for detecting and managing prostate cancer, even when performed for patients with gray-zone PSA levels.

Locally recurrent prostate cancer after high-dose-rate brachytherapy: the value of diffusion-weighted imaging, dynamic contrast-enhanced MRI, and T2-weighted imaging in localizing tumors

OBJECTIVE

The purpose of this article is to retrospectively evaluate the utility of prostate MRI for detecting locally recurrent prostate cancer after high-dose-rate (HDR) brachytherapy.

MATERIALS AND METHODS

Sixteen men with biochemical failure after HDR brachytherapy for prostate cancer underwent prostate MRI, including T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI), using a 1.5-T MRI unit before 12-core-specimen biopsy. Two radiologists in consensus assessed the presence of tumor on each sequence within eight regions of the prostate (six from the peripheral zone [PZ] and two from the transition zone [TZ]) on the basis of biopsy.

RESULTS

Biopsy revealed locally recurrent prostate cancer in 22 (17 in PZ and five in TZ) of 128 regions (17.2%). The sensitivity, specificity, and accuracy of each MRI method in the detection of recurrent tumor were 27%, 99%, and 87%, respectively, for T2-weighted imaging; 50%, 98%, and 90%, respectively, for DCE-MRI; and 68%, 95%, and 91%, respectively, for DWI. The sensitivity of DWI in detecting recurrent tumor was significantly higher than that of T2-weighted imaging (p = 0.004). Multiparametric MRI achieved the highest sensitivity (77%) but with slightly decreased specificity (92%).

CONCLUSION

These results indicate that a multiparametric MRI protocol that includes DWI provides a sensitive method to detect local recurrence after HDR brachytherapy.

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.

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.

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.

MRI of the prostate: interobserver agreement compared with histopathologic outcome after radical prostatectomy

BACKGROUND

The purpose of this study was to evaluate interobserver agreement of prostatic MRI in assessing the performance of staging prostate carcinoma in comparison with histopathologic step section prostate specimens.

METHODS

We retrospectively evaluated 46 patients who underwent prostatic MRI examination at 1.5 T MRI and "subsequently" radical prostatectomy. All MR-images were reevaluated by two different experienced radiologists (15 and 1.5 years of experience) with special focus on T2/T3 differentiation. Both radiologists were not aware of the patient's clinical data, except that the patient had prostate cancer. These findings were compared with histopathologic whole mount step section prostate specimens, which served as the "gold standard". Fourfold tables were created to calculate sensitivity, specificity, positive and negative predictive values and efficiency for T2/T3 differentiation. Cohen's kappa was calculated to measure inter-rater agreement.

RESULTS

Twenty-eight patients were diagnosed with organ defined cancer (T2), 18 patients were staged with extracapsular extension (T3), and thereof 7 patients were staged with seminal vesicle invasion (T3b) by the pathologists. The experienced reader reached a sensitivity of 77.78% (95%-CI 52.36%; 93.59%) and specificity of 92.86% (95%-CI 76.50%; 99.12%) for T2/T3 differentiation, the less experienced reader however achieved a sensitivity of 33.33% (95%-CI 13.34%; 59.01%) and specificity of 71.43% (95%-CI 51.33%; 86.78%). The Cohen's kappa for inter-rater reliability for differentiation between T2 and T3 stage was κ=0.0129.

CONCLUSIONS

Evaluation of prostatic MR imaging requires lengthy experience for accurate interpretation and staging. While a highly experienced reader can achieve good correlation with histopathology even without utilization of functional MR imaging, a less experienced reader with theoretical knowledge falls short of expectation.

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.

Does performance of robot-assisted laparoscopic radical prostatectomy within 2 weeks of prostate biopsy affect the outcome?

OBJECTIVE

The aim of this study was to determine whether robot-assisted laparoscopic radical prostatectomy (RALP) performed within either 2 or 4 weeks of prostate biopsy is associated with surgical difficulty or immediate postoperative outcome.

METHODS

Of the 121 patients that underwent RALP at our institution, 104 patients were prospectively included. Patients were sequentially divided into three groups: first patient in group A (interval from biopsy to RALP: 2 weeks), second patient in group B (2-4 weeks), third patient in group C (more than 4 weeks), fourth patient in group A, and so on. The clinical, operative, pathological, and postoperative functional data were collected.

RESULTS

Group A consisted of 31 patients, group B of 33, and group C of 40 patients. Median patient age and median follow up were 61.1 years and 14.1 months, respectively. In group A, mean estimated blood loss was significantly higher than the other two groups, even though there was no significant difference in the mean console time. Postoperative complications did not make any difference among the groups. In the multivariable analysis, the interval from biopsy to surgery did not affect operative times or surgical margins, or the immediate postoperative outcomes (e.g. recovery of erectile function, continence, and biochemical recurrence).

CONCLUSION

A short interval for less than two weeks between the prostate biopsy and the RALP seems to be feasible and safe. Further studies with larger samples are needed to corroborate these findings.

MRS-guided HDR brachytherapy boost to the dominant intraprostatic lesion in high risk localised prostate cancer

Background

It is known that the vast majority of prostate cancers are multifocal. However radical radiotherapy historically treats the whole gland rather than individual cancer foci.

Magnetic resonance spectroscopy (MRS) can be used to non-invasively locate individual cancerous tumours in prostate. Thus an intentionally non-uniform dose distribution treating the dominant intraprostatic lesion to different dose levels than the remaining prostate can be delivered ensuring the maximum achievable tumour control probability.

The aim of this study is to evaluate, using radiobiological means, the feasibility of a MRS-guided high dose rate (HDR) brachytherapy boost to the dominant lesion.

Methods

Computed tomography and MR/MRS were performed for treatment planning of a high risk localised prostate cancer. Both were done without endorectal coil, which distorts shape of prostate during the exams.

Three treatment plans were compared:

- external beam radiation therapy (EBRT) only

- combination of EBRT and HDR brachytherapy

- combination of EBRT and HDR brachytherapy with a synchronous integrated boost to the dominant lesion

The criteria of plan comparison were: the minimum, maximum and average doses to the targets and organs at risk; dose volume histograms; biologically effective doses for organs at risk and tumour control probability for the target volumes consisting of the dominant lesion as detected by MR/MRS and the remaining prostate volume.

Results

Inclusion of MRS information on the location of dominant lesion allows a safe increase of the dose to the dominant lesion while dose to the remaining target can be even substantially decreased keeping the same, high tumour control probability. At the same time an improved urethra sparing was achieved comparing to the treatment plan using a combination of EBRT and uniform HDR brachytherapy.

Conclusions

MRS-guided HDR brachytherapy boost to dominant lesion has the potential to spare the normal tissue, especially urethra, while keeping the tumour control probability high.

Metabolic characterization of primary and metastatic ovarian cancer by 1H-MRS in vivo at 3T

(1)H-MRS was performed on 12 women (age range 45-72) with ovarian cancer of FIGO stage 3 or above using a 3T MRI system with an 8-channel cardiac receive coil. Respiratory-triggered PRESS-localized spectra (TE = 144 ms) were obtained separately from an ovarian mass and from metastatic disease. Peak areas were quantified relative to unsuppressed water using LCModel and spectra were discarded if LCModel reported signal-to-noise ratio (SNR) < 3 or if no metabolites were reported with standard deviation (SD) < 30%. The cystic fraction of each voxel was estimated by thresholding T(2)-weighted images, and this was used both to correct the reported metabolite concentrations and to calculate an expected SNR of choline using the measured SNR of water. Choline was detected in 10/12 primary tumors and 5/11 metastatic lesions (range 2.0-16.6 mM). Of the 8/23 failures, 7 had a predicted choline SNR < 2, confirming that the failure to detect choline could be explained by technical problems. Glycine was observed in one benign lesion. (1)H-MRS can be used to quantify choline in primary and metastatic masses in ovarian cancer, but the moderately high rate of failure to detect choline necessitates careful recording of data quality parameters to discriminate true from false negatives.

Biopsy related prostate status does not affect on the clinicopathological outcome of robotic assisted laparoscopic radical prostatectomy

PURPOSE

To determine whether the biopsy core number and time interval between prostate biopsy and radical prostatectomy affect the operative and oncologic outcome of robot assisted laparoscopic radical prostatectomy (RALP).

MATERIALS AND METHODS

From January 2008 to April 2009, a single surgeon performed 72 RALPs after an initial learning period of 30 cases. The relationship between time from biopsy to prostatectomy and biopsy core number with operative time and estimated blood loss (EBL) were initially evaluated with a linear regression model. These patients were classified into groups according to whether the interval from biopsy to RALP was within four weeks or not, and whether there were less than or greater than 10 core specimens removed.

RESULTS

RALP was performed in 34 patients within four weeks of biopsy, and in 38 patients more than 4 weeks after biopsy. According to the number of core specimens removed, less than 10 cores were performed in 10 patients, and more than 10 cores were performed in 62 patients. Using an interval of 4 weeks as the cutoff point, early surgery was associated with longer operating time (232.6 vs 208.8 min) and increased estimated blood loss (305.1 vs 276.9 mL). For cases with more than 10 biopsy cores, there was a slight increase in operative time (229.2 vs 210.3 min). None of these differences were statistically significant by multivariate analysis.

CONCLUSION

Our data suggests that there is no reason to delay RALP to more than 4 weeks after prostate biopsy. It also revealed that the number of biopsy cores (up to 14) did not influence operative outcome. Thus, RALP is a feasible procedure regardless of the biopsy related prostate state.

Diffusion-weighted imaging with apparent diffusion coefficient mapping and spectroscopy in prostate cancer

Prostate cancer is a major health problem, and the exploration of noninvasive imaging methods that have the potential to improve specificity while maintaining high sensitivity is still critically needed. Tissue changes induced by tumor growth can be visualized by magnetic resonance imaging (MRI) methods. Current MRI methods include conventional T2-weighted imaging, diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping and magnetic resonance spectroscopy (MRS). Techniques such as DWI/ADC provide functional information about the behavior of water molecules in tissue; MRS can provide biochemical information about the presence or absence of certain metabolites, such as choline, creatine, and citrate. Finally, vascular parameters can be investigated using dynamic contrast-enhanced MRI. Moreover, with whole-body MRI and DWI, metastatic disease can be evaluated in 1 session and may provide a way to monitor treatment. Therefore, when combining these various methods, a multiparametric data set can be built to assist in the detection, localization, assessment of prostate cancer aggressiveness, and tumor staging. Such a comprehensive approach offers more power to evaluate prostate disease than any single measure alone. In this article, we focus on the role of DWI/ADC and MRS in the detection and characterization using both in vivo and ex vivo imaging of prostate pathology.

Dynamic contrast-enhanced magnetic resonance imaging in the evaluation of the prostate

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a novel MR technique that allows to interrogate pharmacokinetic processes in the tissues at a voxel level and to generate parametric maps that can be displayed for clinical interpretation. Dynamic contrast-enhanced MRI is an important imaging technique for the imaging of angiogenesis and vasculogenesis because it probes the microvascular networks at a microscopic level by being sensitive to the compartmentalization of tissue into the vascular and extravascular-extracellular space and to the diffusion of contrast molecules across the vascular endothelium and capillary boundaries. Dynamic contrast-enhanced MRI has already shown to improve detection and localization of prostate cancer, to improve prediction of extracapsular extension, determination of tumor volume, and after treatment follow-up. In this article, we outline the fundamental principles of DCE-MRI and describe the application of DCE methods in the imaging of the prostate.

Prognostic factors in patients with acute liver failure undergoing live donor liver transplantation

Mortality from acute liver failure (ALF) is high. Live donor liver transplantation (LDLT) is the treatment of choice for ALF in Asia, because cadaveric donors are rare. We sought to review our results in ALF patients with undergoing LDLT at our center. One hundred two LDLTs were performed at our center from April 2002 to November 2007, 15 (14%) because of ALF. Mean (SEM; median, range) follow-up was 1,065 (189; 1400; 3-2046) days. Nine patients (60%) had acute exacerbation of chronic hepatitis B; and 6 (40%) had drug-induced liver injury. Age was 47 (3; 50; 27-65) years. Ten patients (67%) were men. At transplantation, laboratory values were included bilirubin, 449 (35) micromol/L; creatinine concentration, 182 (32) mmol/L. The international normalized ratio was 2.4 (0.2). The Model for End-Stage Liver Disease (MELD) score was 34 (2). Both inpatient and long-term mortality was 20% 3 of 15 patients died. The 5-year survival was 80%. Compared with survivors, patients who died had a significantly higher creatinine concentration 289 vs 155 micromol/L, international normalized ratio (3.4 vs 2.1), MELD score (47 vs 32). We conclude that despite being sick with median and mean MELD scores of 32 and 34, 80% of patients with ALF can achieve good long-term survival after LDLT.