Negative predictive value of multiparametric MRI for prostate cancer detection: Outcome of 5-year follow-up in men with negative findings on initial MRI studies

Objective

To assess the clinical negative predictive value (NPV) of multiparametric MRI (mp-MRI) for prostate cancer in a 5-year follow-up.

Materials and methods

One hundred ninety-three men suspected of harboring prostate cancer with negative MRI findings were included. Patients with positive transrectal ultrasound (TRUS)-guided biopsy findings were defined as false-negative. Patients with negative initial TRUS-guided biopsy findings were followed up and only patients with negative findings by digital rectal examination, MRI, and repeat biopsy and no increase in PSA at 5-year follow-up were defined as “clinically negative”. The clinical NPV of mp-MRI was calculated. For quantitative analysis, mean signal intensity on T2-weighted images and the mean apparent diffusion coefficient value on ADC maps of the initial MRI studies were compared between peripheral-zone (PZ) cancer and the normal PZ based on pathologic maps of patients who had undergone radical prostatectomy.

Results

The clinical NPV of mp-MRI was 89.6% for significant prostate cancer. Small cancers, prostatitis, and benign prostatic hypertrophy masking prostate cancer returned false-negative results. Quantitative analysis showed that there was no significant difference between PZ cancer and the normal PZ.

Conclusion

The mp-MRI revealed a high clinical NPV and is a useful tool to rule out clinically significant prostate cancer before biopsy.     

Local anesthesia by periprostatic block in transrectal ultrasound guided prostatic biopsy

Objective

To evaluate the efficacy of local anesthetic by peri-prostatic block in decreasing the pain and discomfort experienced by patients undergoing transrectal ultrasound (TRUS)-guided biopsy of prostate.

Patients and methods

Fifty patients were submitted for TRUS-guided prostate biopsy. Patients were randomized in two groups: group-I, with 25 patients submitted to local anesthesia by 5 ml of 1% lidocaine injected at each side at the Mount of Everest and group-II, with 25 patients who underwent TRUS biopsy by conventional method with local xylocaine cream. After biopsy, patients were questioned about pain intensity during the procedure, using a grading scale from 0 to 10. Side effects and later complications of the procedure were also evaluated.

Results

Group I patients with peri-prostatic block had a significantly lower pain score compared with group II without LA. In LA group the mean pain scores were 3.0 ± 1.8 and in group II patients with conventional method of biopsy it was 6.4 ± 2.2 (p < 0.001). There were no significant problems associated with LA infiltration.

Conclusion

TRUS-guided prostate biopsy is a traumatic and painful experience, but the peri-prostatic blockage use is clearly associated with more tolerance and patient comfort during the exam.     

Detection of prostate cancer with three-dimensional transrectal ultrasound: correlation with biopsy results

Objectives

The aim of this study was to evaluate the role of three-dimensional transrectal ultrasound in the diagnosis of prostate cancer.

Methods

A total of 112 patients with elevated serum prostate-specific antigen (PSA) or a positive digital rectal examination were evaluated using three-dimensional greyscale transrectal ultrasound (3D-GS TRUS) and three-dimensional power Doppler sonography (3D-PDS). Target biopsies were obtained together with 12 core systematic biopsies. Pathological results were correlated with the imaging data.

Results

Cancers were detected in 269 biopsy sites from 41 patients. 229 sites of cancer were depicted by 3D-GS TRUS and 213 sites were depicted by 3D-PDS. 30 sites were missed by both 3D-GS TRUS and 3D-PDS. Abnormal prostate images depicted by 3D-GS TRUS and 3D-PDS were associated with lesions with a Gleason score of 6.9 or higher.

Conclusion

The detection rates of prostate cancer were significantly improved with 3D-GS TRUS and 3D-PDS on serum PSA levels >10 ng ml^–1 or 20 ng ml^–1. 3D-GS TRUS and 3D-PDS may improve the biopsy yield by determining appropriate sites for target and systematic biopsies. The abnormalities detected by 3D ultrasound were associated with moderate- and high-grade prostate cancers. However, based on the number of false-negative TRUS results, the use of systematic prostate biopsies should not be eliminated.Prostate cancer is a common malignancy in older males. Previous autopsy studies have shown that one-third of males over 50 years old have latent cancer, yet only 10% develop clinically significant carcinomas during their lifetime [1]. The exact mechanism mediating the progression of microfocal cancers into symptomatic forms of the disease has not been elucidated. Since prostate cancers demonstrate remarkably heterogeneous behaviours ranging from slow-growing lesions to aggressive tumours that metastasise rapidly [2], the diagnosis and treatment of prostate cancers is very challenging. The current methods of screening for prostate cancer include measuring serum prostate-specific antigen (PSA) levels, digital rectal examination and transrectal ultrasound (TRUS) scanning and biopsy. However, controversy surrounds which screening method is the most clinically significant for detecting lesions.Since approximately 20–50% of prostate cancers are invisible by greyscale (GS) TRUS [3], GS TRUS has limited value for detection of prostate cancer [4,5]. In addition, 35% of lesions missed by GS TRUS are moderate- or high-grade tumours [6]. Colour Doppler ultrasound, as an important adjunct to GS TRUS, could improve detection of prostate cancer, although in one study 16% of cases with clinically significant cancer were still missed by this method [7].Three-dimensional (3D) TRUS is a relatively new imaging modality. Preliminary studies have shown improved cancer detection with 3D TRUS when compared with two-dimensional TRUS [8,9]. However, it is still unknown which malignant lesions may be detected by 3D TRUS. Furthermore, 3D TRUS has not been analysed in correlation with the site-specific biopsy pathological results.The purpose of this study was to assess the role of 3D-GS TRUS and 3D power Doppler sonography (3D-PDS) in the diagnosis of prostate carcinoma. This study correlated 3D-GS TRUS and 3D-PDS data with biopsy pathological results using a site-by-site analysis that included target and systematic biopsies.     

Detection and localization of carcinoma within the prostate using high resolution transrectal gamma imaging (TRGI) of monoclonal antibody directed at prostate specific membrane antigen (PSMA)—Proof of concept and initial imaging results

Purpose

Molecular imaging methods may identify primary prostate cancer foci and potentially guide biopsy and optimal management approaches. In this exploratory study, safety and first human imaging experience of a novel solid state endocavity transrectal gamma-imaging (TRGI) device was evaluated.

Methods

Twelve patients received 5 ± 0.5 mCi In-111 capromab pendetide (ProstaScint^®) intravenously and the prostate of each was imaged 4 days later transrectally using an endoluminal cadmium zinc telluride (CZT)-based compact gamma camera (ProxiScan™, Hybridyne Imaging Technologies, Inc.). Immediate and 5–7-day post imaging safety assessments were performed. In those patients with a prostate cancer diagnosis (N = 10), single photon emission computed tomography (SPECT-CT) and magnetic resonance imaging (MRI) of the pelvis were also acquired. Images were reviewed and sites of suspected cancer were localized by prostate quadrant by consensus of two nuclear medicine physicians. Pathology from TRUS biopsy, or surgical pathology following prostatectomy (N = 3) when available, served as the gold standard.

Results

There were no serious adverse events associated with TRGI. No focal signal was detected in patients without a diagnosis of prostate cancer (N = 2). Of 40 quadrants evaluated in the cancer cohort (N = 10), 22 contained malignancy. In 8 of these 10 patients, the most focal site of uptake on TRGI corresponded to a prostatic quadrant with biopsy-proven malignancy. In 6 cancer-containing quadrants, TRGI was positive where SPECT-CT was negative; MRI showed a detectable abnormality in only 1 of these 6 quadrants. Qualitative image review of the planar TRGI images for prostate cancer localization was severely limited in some cases by scatter artifact within the vicinity of the prostate gland arising from physiologic urine and blood pool activity from nearby structures.

Conclusions

TRGI is a safe imaging method that can potentially detect radiopharmaceutical uptake of primary prostate cancer and facilitate prostatic quadrant – localization of cancer. Further investigation of this technology is warranted.     

Value of contrast-enhanced sonographic micro flow imaging for prostate cancer detection with t-PSA level of 4-10ng/mL

Objectives

To compare the efficiency of contrast-enhanced ultrasonographic micro flow imaging (MFI) with conventional transrectal ultrasound (TRUS) in detecting prostate cancer with serum total prostate-specific antigen (t-PSA) of 4.0–10.0 ng/mL. To evaluate the value of contrast-enhanced ultrasonographic MFI in detecting prostate cancer with t-PSA in diagnostic gray zone.

Methods

47 patients with t-PSA 4.0–10.0 ng/mL underwent gray scale, power Doppler TRUS and MFI examinations before ultrasound guided biopsies. Biopsies were performed at twelve sites in the base, the mid-gland and the apex of the prostate in each patient, when there was no abnormal ultrasound finding. When an abnormality was present at MFI, the biopsy specimen from the corresponding site was directed toward the abnormal finding. With histological results of prostate biopsy as reference standards, we assessed the cancer detection of these three methods.

Results

564 specimens were collected in this study, in which 101 were prostate cancer confirmed histologically. 152 of 564 specimens were demonstrated abnormal on MFI images, in which 71 were malignant and 81 were benign confirmed histologically. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for MFI in detecting prostate caner were 70.3%, 82.5%, 80.3%, 46.7% and 92.7%, respectively. The sensitivity and NPV for MFI were significantly better than gray scale (38.6%, 86.9%) and power Doppler (32.7%, 86.0%) (P < 0.001) TRUS.

Conclusions

Contrast-enhanced ultrasonographic MFI could significantly improve the detection rate of prostate cancer with t-PSA in diagnostic gray zone (4–10 ng/mL) than conventional ultrasound.     

The role of three dimensional transrectal ultrasonography (3-D TRUS) and power Doppler sonography in prostatic lesions evaluation

Aim of work

To evaluate the role of three dimensional (3D), two dimensional (2D) as well as power Doppler transrectal ultrasound (TRUS) in diagnosis of different prostatic lesions.

Patients and methods

2-D TRUS, power Doppler and Transrectal 3-D US were performed for 100 patients between April 2009 and April 2010. All patients had been examined clinically with digital rectal examination (DRE) and had serum prostatic specific antigen (PSA) level (total and free). Patient age ranges from 42 to 67 years and the mean age was 55 years. TRUS guided biopsies were done for 77 cases showing any of the followings: abnormal focal lesion with ultrasound, abnormal vascularity with power Doppler exam, abnormal DRE, elevated serum total PSA >4 ng/ml or when the percent-free PSA is 10% or less in an outpatient setting. The results were recorded and analyzed.

Results

3-D TRUS was more sensitive, specific and more accurate than 2-D TRUS in detecting prostate cancer as it showed estimated sensitivity 78.9% and specificity 94.8% with total accuracy 90.9% with respect to an estimated sensitivity 63.1%, specificity 86.2% and total accuracy 80.5% with 2-D TRUS and was more accurate than 2-D ultrasound in identifying the capsular breaks with an estimated sensitivity 80% with respect to 40% with 2-D TRUS.Power Doppler showed 84.2% sensitivity in detecting prostatic cancer and was of 100% sensitivity in detecting prostatitis. 3-D TRUS was more accurate in estimating the volume of adenoma in cases of BPH with an estimated error not more than +6% with respect to an estimated error not more than +18% for 2-D TRUS.

Conclusion

3-D transrectal ultrasound and power Doppler sonography have specific diagnostic capabilities which added significantly to the ultrasound in detecting and staging of prostatic cancer and in the planning for management .They proved highly valuable in the diagnosis of prostatitis and 3-D TRUS was more accurate than 2-D TRUS in estimating the volume of adenomas in patients with BPH.     

MR-guided biopsy of the prostate: Comparison of diagnostic specimen quality with 18G and 16G biopsy needles

Purpose

To evaluate specimen quality and diagnostic differences between magnetic resonance (MR) compatible 16G and 18G biopsy needles in MR-guided biopsy (MRGB) of the prostate.

Materials and methods

Semiautomatic MR compatible biopsy needles with a diameter of 16G (Group A) or 18G (Group B) were used to perform MRGB in 88 patients with suspected prostate cancer. After embedding and staining, length and width of all specimens (140 cores in Group A, 143 in Group B) were measured. Fragmentation, squeezing artifacts, and overall evaluability were evaluated using a quality score from 0 (no tissue) to 3 (optimal tissue quality). Groups were statistically compared; p-values <0.05 were regarded as significant.

Results

Demographic data were not significantly different between Group A and B with a mean age of 63 ± 7.3 and 67 ± 5.7 years; and a mean prostate-specific antigen of 12.6 ± 10.3 ng/ml and 13.8 ± 11.6 ng/ml, respectively (p = 0.70). Area of longitudinally sectioned histological specimens was significantly larger in Group A than in Group B with 9.38 mm² (8.74; 10.02) and 7.95 mm² (7.32; 8.59), respectively (p = 0.002). However, there were significantly more cores without prostate tissue with 18 cores (12.9%) versus 3 cores (2.1%) in Groups A and B, respectively (p = 0.004). Fragmentation, squeezing artifacts, and overall evaluability were not statistically different between the two groups. The rate of prostate cancer in the cores was also not significantly different between Groups A and B (22.1% and 24.5%; p = 0.77).

Conclusion

16G biopsy needles do not provide a relevant diagnostic advantage over 18G needles in MRGB. Therefore, use of 18G needles is not discouraged and may even be preferred as it is not expected to result in a relevant degradation of specimen quality or compromise in prostate cancer detection rate.     

Prostate cancer: 1.5 T endo-coil dynamic contrast-enhanced MRI and MR spectroscopy—correlation with prostate biopsy and prostatectomy histopathological data

Purpose

To investigate diagnostic accuracy of detection of prostate cancer by magnetic resonance: to evaluate the performance of T2WI, DCEMRI and CSI and to correlate the results with biopsy and radical prostatectomy histopathological data.

Materials and methods

43 patients, scheduled for radical prostatectomy, underwent prostate MR examination. Prostate cancer was identified by transrectal ultrasonographically (TRUS) guided sextant biopsy. MR examination was performed at 1.5T with an endorectal MR coil. Cancer localisation was performed on sextant-basis - for comparison between TRUS biopsy, MR techniques and histopathological findings on prostatectomy specimens.

Results

Prostate cancer was identified in all 43 patients by combination of the three MR techniques. The detection of prostate cancer on sextant-basis showed sensitivity and specificity: 50% and 91% for TRUS, 72% and 55% for T2WI, 49% and 69% for DCEMRI, and 46% and 78% for CSI.

Conclusion

T2WI, DCEMRI and CSI in combination can identify prostate cancer. Further development of MR technologies for these MR methods is necessary to improve the detection of the prostate cancer.     

T2-weighted hypointense lesions within prostate gland: Differential diagnosis using wash-in rate parameter on the basis of dynamic contrast-enhanced magnetic resonance imaging—Hystopatology correlations

Background and aims

Dynamic contrast enhanced magnetic resonance improves prostate cancer detection. The aims of this paper are to verify whether wash-in-rate parameter (speed of contrast uptake in dynamic contrast enhanced magnetic resonance) can help to differentiate prostate cancer from non-neoplastic T2-weighted hypointense lesions within prostate gland and to assess a cut-off for prostate cancer diagnosis.

Methods

Prospective, monocentric, multi-departmental study. Thirty consecutive patients underwent T2-weighted and dynamic contrast enhanced magnetic resonance, and re-biopsy. T2-weighted hypointense lesions, >5 mm in size, were noted. Lesions were assessed as cancerous (showing mass effect, or no defined margin within transitional zone) and non cancerous (no mass effect) and were compared with histopathology by 2 × 2 tables. Wash-in-rate of each lesion was calculated and was correlated with histopathology. Student's t-test was adopted to assess significant differences. Receiver operating characteristic (ROC) analysis was employed to identify the best cut-off for wash-in-rate in detecting prostate cancer.

Results

At re-biopsy, cancer was proven in 43% of patients. On T2-weighted MRI, 111 hypointense lesions ≥5 mm in size were found. Sensitivity, specificity and accuracy of T2-weighted MRI were 80% (±12.4 CI 95%), 74.6% (±10.1 CI 95%), and 76.5% (±7.9 CI 95%), respectively. Mean WR was 5.8 ± 1.9/s for PCa zones and 2.96 ± 1.44/s for non-PCa zones (p < 0.00000001). At ROC analysis, the best area under curve (AUC) for wash-in-rate parameter was associated to 4.2/s threshold with 82.5% sensitivity (CI ± 7.07), 97.2% specificity (CI ± 4.99) and 91.2% accuracy (CI ± 5.27). Eighteen false positive lesions on T2-weighted MRI showed low wash-in-rate values suggesting non-cancer lesions, while in 5/8 false negative cases high wash-in-rate values correctly suggested prostate cancer. Nine lesions with surgically proven cancer were not included in the saturation biopsy scheme, in 2/9 cases the only site of cancer.

Conclusions

Wash-in-rate parameter allows to differentiate prostate cancer from non-neoplastic lesions, helping cancer detection in areas not included in the biopsy scheme.     

A qualitative approach to combined magnetic resonance imaging and spectroscopy in the diagnosis of prostate cancer

Purpose

To investigate the feasibility and diagnostic value of a whole prostate qualitative approach to combined magnetic resonance imaging and spectroscopy (MRI + MRS) in the detection of prostate cancer in patients with elevated PSA.

Materials and methods

Three hundred and fifty six subjects (mean serum PSA 11.47 ng/ml, range 0.40-133 ng/ml) were examined with fast-T2-weighted images (MRI) and 3D-magnetic resonance spectroscopy (MRS). Both modalities were qualitatively analyzed on a whole prostate basis by a single radiologist using a 4-point diagnostic scale. Prostate cancer was histopathologically proven in 220 patients and non-evidence of cancer was determined after at least 12 months clinical follow-up in 136 subjects.

Results

Receiver operating curve analysis revealed a significantly better diagnostic performance of MRI + MRS (A_z = 0.857) than MRI alone (A_z = 0.801) and MRS alone (A_z = 0.810). The sensitivity, specificity and accuracy of MRI + MRS for detection of prostate cancer were 72.3%, 92.6%, and 80.1%, respectively.

Conclusions

Spectral evaluation with a whole prostate qualitative approach is feasible in routine clinical practice. The combination of MRI and MRS yields superior diagnostic results than either modality alone.     

Do apparent diffusion coefficient (ADC) values obtained using high b-values with a 3-T MRI correlate better than a transrectal ultrasound (TRUS)-guided biopsy with true Gleason scores obtained from radical prostatectomy specimens for patients with prostate cancer?

Objective

To investigate the usefulness of apparent diffusion coefficient (ADC) values in predicting true Gleason scores from radical prostatectomy specimen (tGS), compared with systematic transrectal ultrasound (TRUS)-guided biopsy GS (bGS).

Materials and methods

One hundred and five patients with biopsy-proven prostate cancer underwent preoperative DWI (b-values of 0, 1000, and 2000 s/mm²) of 3-T MRI. The mean and minimum ADCs of visible tumors were calculated for either of a pair of b-values: 0 and 1000 s/mm² (ADC₁₀₀₀), or 0 and 2000 s/mm² (ADC₂₀₀₀), and relationships between the four ADC parameters and tGS evaluated for the peripheral zone (PZ) and transition zone (TZ). For multiple tumors, the dominant tumor's GS and ADCs were estimated for cancer aggressiveness assessment by computing ROC curves.

Results

Significant negative correlations were observed between tGS and mean ADC₁₀₀₀, mean ADC₂₀₀₀, minimum ADC₁₀₀₀, and minimum ADC₂₀₀₀ (r = −0.41, −0.39, −0.39, and −0.37, respectively) of 100 visible PZ tumors and 66 visible TZ tumors (r = −0.40, −0.42, −0.29, and −0.21, respectively). For distinguishing high-grade from low/intermediate-grade PZ lesions, the areas under the curve (AUCs) of mean ADC₁₀₀₀ (0.751), mean ADC₂₀₀₀ (0.710), minimum ADC₁₀₀₀ (0.768), and minimum ADC₂₀₀₀ (0.752) were similar to that of the highest bGS (0.708) (p = 0.61, p = 0.98, p = 0.47, and p = 0.60, respectively). For distinguishing high-grade from low/intermediate-grade TZ lesions, AUCs of mean ADC₁₀₀₀ (0.779), and mean ADC₂₀₀₀ (0.811) were similar to that of the highest bGS (0.805) (p = 0.83 and p = 0.97).

Conclusion

Tumor ADCs obtained with high b-values could predict prostate cancer aggressiveness as effectively as systematic TRUS-guided biopsy.     

Underestimation of invasive lesions in patients with ductal carcinoma in situ of the breast diagnosed by ultrasound-guided biopsy: A comparison between patients with and without HER2/neu overexpression

Purpose

To determine the rate of underestimation of ductal carcinoma in situ (DCIS) diagnosed at imaging-guided biopsy and to analyze its association with HER2/neu oncogene, an important biomarker in assessing the tumour aggressiveness and guiding hormone therapy for breast cancer.

Methods

We retrospectively reviewed 162 patients with DCIS diagnosed by imaging-guided core needle biopsy between January 2008 and March 2013. All of these patients received surgical excision, and in 25, the diagnosis was upgraded to invasive breast cancer. In this study, we examined the ultrasound, mammographic features and histopathological results for each patient, and compared these parameters between those with and without HER2/neu overexpression.

Results

Of the 162 DCIS lesions, 110 (67.9%) overexpressed HER2/neu. Nineteen patients with HER2/neu overexpressing DCIS (n = 19/110, 17.3%) were upgraded after surgery to a diagnosis of invasive breast cancer. In this group, the upgrade rate was highest in patients with a dilated mammary duct pattern (42.1%, n = 8/19, p = 0.02) and the presence of abnormal axillary nodes (40.0%, n = 12/30, p < 0.01) at ultrasound and was significantly associated with comedo tumour type on pathology.

Conclusions

Biopsy may underestimate the invasive component in DCIS patients. Sonographic findings of dilated mammary ducts and presence of abnormal axillary lymph nodes may help predicting the invasive components and possibly driving more targeted biopsy procedures.     

Incremental diagnostic value of targeted biopsy using mpMRI-TRUS fusion <Emphasis Type="Italic">versus</Emphasis> 14-fragments prostatic biopsy: a prospective controlled study

Objectives

To compare the incremental diagnostic value of targeted biopsy using real-time multiparametric magnetic resonance imaging and transrectal ultrasound (mpMRI-TRUS) fusion to conventional 14-cores biopsy.

Patients and Methods

Uni-institutional, institutional review board (IRB) approved prospective blinded study comparing TRUS-guided random and targeted biopsy using mpMRI-TRUS fusion, in 100 consecutive men. We included men with clinical-laboratorial suspicious for prostate cancer and Likert score ≥ 3 mp-MRI. Patients previously diagnosed with prostate cancer were excluded. All patients were submitted to 14-cores TRUS-guided biopsy (mpMRI data operator-blinded), followed by targeted biopsy using mpMRI-TRUS fusion.

Results

There was an overall increase in cancer detection rate, from 56% with random technique to 62% combining targeted biopsy using mpMRI-TRUS fusion; incremental diagnosis was even more relevant for clinically significant lesions (Gleason ≥ 7), diagnosing 10% more clinically significant lesions with fusion biopsy technique. Diagnosis upgrade occurred in 5 patients that would have negative results in random biopsies and had clinically significant tumours with the combined technique, and in 5 patients who had the diagnosis of significant tumours after fusion biopsy and clinically insignificant tumours in random biopsies(p=0.0010).

Conclusions

Targeted biopsy using mpMRI-TRUS fusion has incremental diagnostic value in comparison to conventional random biopsy, better detecting clinically significant prostate cancers.

Key Points

? mpMRI-TRUS targeted biopsy increases overall cancer detection rate, but not statistically significant.? mpMRI-TRUS targeted biopsy actually improves the diagnosis of clinically significant PCa.? There was no evidence to acquire the mpMRI-TRUS fusion cores alone.

     

Multiparametric MRI of the prostate with three functional techniques in patients with PSA elevation before initial TRUS-guided biopsy

Objective:

Multiparametric MRI (mp-MRI) of the prostate is increasingly being used for local staging and detection of recurrence of prostate cancer (PCA). In patients with elevated prostate-specific antigen (PSA), mp-MRI could provide information on the position of the cancer, allowing adjustments to be made to the needle depth and direction before repeat transrectal ultrasound (TRUS)-guided biopsy to ensure accurate sampling of lesions. The purpose of the prospective study was to evaluate mp-MRI of the prostate in patients with PSA elevation before initial TRUS-guided biopsy.

Methods:

mp-MRI was performed in 94 patients using a 1.5-T scanner (MAGNETOM Aera^®; Siemens Healthcare, Erlangen, Germany) and 16-channel phased-array body coil (Siemens Healthcare). T₂ weighted images (T2WI), diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI and MR spectroscopy were obtained. TRUS-guided random biopsies and additional targeted biopsies of suspicious MRI areas were performed.

Results:

Additional targeted biopsies were obtained in 17 of 43 (40%) patients with PCA. 11 of 17 targeted biopsies contained PCA. 5 of 11 PCAs were diagnosed only by additional targeted biopsies. Sensitivity of mp-MRI in patients was 97.7% and specificity was 11.8%. mp-MRI was false negative in one patient. Sensitivity of mp-MRI in 207 lesions was 80.9% and specificity was 44.7%. In a logistic regression model, the apparent diffusion coefficient value was the only significant parameter to differentiate malignant and benign lesions.

Conclusion:

mp-MRI should be performed in patients with PSA elevation before initial TRUS-guided biopsy to allow additional targeted biopsies from suspicious areas of MRI. We recommend mp-MRI with T2WI, DWI, DCE MRI and MR spectroscopy. DWI as the most reliable technique should be used in every mp-MRI.

Advances in knowledge:

DWI is the most reliable technique in mp-MRI of the prostate.     

Diffusion-weighted MR imaging and ADC measurement in normal prostate,benign prostatic hyperplasia and prostate carcinoma

Purpose

Our aim was to investigate the diffusion-weighted Imaging (DWI) appearance and apparent diffusion coefficient (ADC) values of normal prostatic gland, prostate carcinoma (PCa) and benign prostate hyperplasia (BPH) and to determine the utility of DWI in their characterization.

Materials and methods

During a period of 16 months, 40 consecutive patients, with elevated PSA level and 12 healthy volunteers with no clinical symptoms or history of prostate disease were prospectively evaluated with DWI of the prostate. MRI was performed using a 1.5T MR scanner equipped with a pelvic phased array coil. For anatomical imaging, T2W FSE in the three orthogonal planes, and T1WI in axial plane were obtained. DWI with b values of 0, 300, 500 and 800 s/mm² were performed in axial plane. The results were confirmed by TRUS-guided biopsy or prostatectomy.

Results

Patients ranged in age from 45 to 85 years (mean 66.6 ± 7.9 year). Twenty patients were confirmed to have BPH, whereas 20 patients had PCa. The mean and SD of ADC values for the peripheral zone (PZ), central gland (CG), BPH nodules and PCa were 1.839 ± 0.233, 1.469 ± 0.239, 1.359 ± 0.201 and 0.87 ± 0.13 respectively. The mean ADC value of PCa was significantly lower than that of CG, PZ, and BPH nodule, with p value <0.05.

Conclusion

DW MR imaging characteristics and ADC values can differentiate PCa and BPH. DWI with ADC may be used as a complementary method to conventional MRI in diagnosis of PCa and BPH.     

Diagnostic utility of DTI in prostate cancer

Purpose

The aim of this study was to compare the diffusion tensor parameters of prostate cancer, prostatitis and normal prostate tissue.

Materials and Methods

A total of 25 patients with the suspicion of prostate cancer were included in the study. MRI was performed with 3 T system (Intera Achieva, Philips Medical Systems, The Netherlands). T2 TSE and DTI with ss-EPI were obtained in each subject. TRUS-guided prostate biopsy was performed after the MRI examination. Images were analyzed by two radiologists using a special software system. ROI's were drawn according to biopsy zones which are apex, midgland, base and central zone on each sides of the gland. FA and ADC values in areas of cancer, chronic prostatitis and normal prostate tissue were compared using Student's t-test.

Results

Histopathological analysis revealed carcinoma in 68, chronic prostatitis in 67 and was reported as normal in 65 zones. The mean FA of cancerous tissue was significantly higher (p < 0.01) than the FA of chronic prostatitis and normal gland. The mean ADC of cancerous tissue was found to be significantly lower (p < 0.01), compared with non-cancerous tissue.

Conclusion

Decreased ADC and increased FA are compatible with the hypercellular nature of prostate tumors. These differences may increase the accuracy of MRI in the detection of carcinoma and to differentiate between cancer and prostatitis.     

MR-perfusion (MRP) and diffusion-weighted imaging (DWI) in prostate cancer: Quantitative and model-based gadobenate dimeglumine MRP parameters in detection of prostate cancer

Background

Various MR methods, including MR-spectroscopy (MRS), dynamic, contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI) have been applied to improve test quality of standard MRI of the prostate.

Purpose

To determine if quantitative, model-based MR-perfusion (MRP) with gadobenate dimeglumine (Gd-BOPTA) discriminates between prostate cancer, benign tissue, and transitional zone (TZ) tissue.

Material and methods

27 patients (age, 65 ± 4 years; PSA 11.0 ± 6.1 ng/ml) with clinical suspicion of prostate cancer underwent standard MRI, 3D MR-spectroscopy (MRS), and MRP with Gd-BOPTA. Based on results of combined MRI/MRS and subsequent guided prostate biopsy alone (17/27), biopsy and radical prostatectomy (9/27), or sufficient negative follow-up (7/27), maps of model-free, deconvolution-based mean transit time (dMTT) were generated for 29 benign regions (bROIs), 14 cancer regions (cROIs), and 18 regions of transitional zone (tzROIs). Applying a 2-compartment exchange model, quantitative perfusion analysis was performed including as parameters: plasma flow (PF), plasma volume (PV), plasma mean transit time (PMTT), extraction flow (EFL), extraction fraction (EFR), interstitial volume (IV) and interstitial mean transit time (IMTT). Two-sided T-tests (significance level p < 0.05) discriminated bROIs vs. cROIs and cROIs vs. tzROIs, respectively.

Results

PMTT discriminated best between bROIs (11.8 ± 3.0 s) and cROIs (24.3 ± 9.6 s) (p < 0.0001), while PF, PV, PS, EFR, IV, IMTT also differed significantly (p 0.00002-0.0136). Discrimination between cROIs and tzROIs was insignificant for all parameters except PV (14.3 ± 2.5 ml vs. 17.6 ± 2.6 ml, p < 0.05).

Conclusions

Besides MRI, MRS and DWI quantitative, 2-compartment MRP with Gd-BOPTA discriminates between prostate cancer and benign tissue with several parameters. However, distinction of prostate cancer and TZ does not appear to be reliable.     

Imaging and pathology findings after an initial negative MRI-US fusion-guided and 12-core extended sextant prostate biopsy session

PURPOSE

A magnetic resonance imaging-ultrasonography (MRI-US) fusion-guided prostate biopsy increases detection rates compared to an extended sextant biopsy. The imaging characteristics and pathology outcomes of subsequent biopsies in patients with initially negative MRI-US fusion biopsies are described in this study.

MATERIALS AND METHODS

We reviewed 855 biopsy sessions of 751 patients (June 2007 to March 2013). The fusion biopsy consisted of two cores per lesion identified on multiparametric MRI (mpMRI) and a 12-core extended sextant transrectal US (TRUS) biopsy. Inclusion criteria were at least two fusion biopsy sessions, with a negative first biopsy and mpMRI before each.

RESULTS

The detection rate on the initial fusion biopsy was 55.3%; 336 patients had negative findings. Forty-one patients had follow-up fusion biopsies, but only 34 of these were preceded by a repeat mpMRI. The median interval between biopsies was 15 months. Fourteen patients (41%) were positive for cancer on the repeat MRI-US fusion biopsy. Age, prostate-specific antigen (PSA), prostate volume, PSA density, digital rectal exam findings, lesion diameter, and changes on imaging were comparable between patients with negative and positive rebiopsies. Of the patients with positive rebiopsies, 79% had a positive TRUS biopsy before referral (P = 0.004). Ten patients had Gleason 3+3 disease, three had 3+4 disease, and one had 4+4 disease.

CONCLUSION

In patients with a negative MRI-US fusion prostate biopsy and indications for repeat biopsy, the detection rate of the follow-up sessions was lower than the initial detection rate. Of the prostate cancers subsequently found, 93% were low grade (≤3+4). In this low risk group of patients, increasing the follow-up time interval should be considered in the appropriate clinical setting.Prostate cancer is the most common cancer in males, with an estimated 238 590 new diagnoses annually in the USA, and it is the second leading cause of cancer-related mortality in males (1). One in six males will develop prostate cancer in his lifetime (1). The current standard of care for diagnosing and grading prostate cancer is a 12-core extended sextant biopsy obtained with transrectal ultrasonography (TRUS) guidance (2, 3). As magnetic resonance imaging (MRI) has superior contrast resolution than ultrasonography (US), it is possible for multiparametric MRI (mpMRI) to detect prostate cancer with high reliability (4). Since clinically insignificant cancer is often invisible to magnetic resonance (MR), prostate MRI preferentially detects more aggressive cancers (5–9). MRI can be used to guide the prostate biopsy, either using a direct “in-gantry” approach or by using MRI-US fusion, which was developed as an office-based alternative (10). MRI-US targeted biopsies have about twice the per-core detection rate of sextant biopsies (11), and have been shown to be particularly useful for prostates measuring greater than 40 mL, which typically have lower rates of cancer detection than smaller prostate glands (12).Since TRUS-guided biopsies have a relatively low sensitivity, many patients with a rising prostate-specific antigen (PSA), but an initial negative biopsy, undergo additional biopsies with progressively lower yields. In a study of sequential systematic biopsies in 1051 males, the detection rate of successive biopsies was 22%, 10%, 5%, and 4%, respectively (13). The third and fourth TRUS-guided biopsy sessions detected lower grade cancers and were found to have higher morbidity than the first two biopsies. Recently, MRI-US fusion biopsy has been reported to increase cancer detection rates in the setting of a prior negative TRUS biopsy (14, 15).While MRI-US fusion biopsy is promising in the setting of previous negative random sampling, the response to a negative MRI-US fusion biopsy is less clear. Since a MRI-US fusion biopsy increases prostate cancer detection, this population should have a lower disease burden than patients with an initial negative TRUS-guided biopsy alone. Now that MRI-US fusion biopsies have been available for several years, such data are beginning to accumulate. Here, we investigate the detection rates of subsequent biopsies in patients with an initial negative MRI-US fusion prostate biopsy.     

Role of diffusion-weighted imaging as an adjunct to contrast-enhanced breast MRI in evaluating residual breast cancer following neoadjuvant chemotherapy

Objective

To investigate whether the addition of diffusion-weighted imaging (DWI) to dynamic contrast-enhanced MRI (DCE-MRI) improves diagnostic performance in predicting pathologic response and residual breast cancer size following neoadjuvant chemotherapy.

Materials and methods

A total of 78 consecutive patients who underwent preoperative breast MRI with DWI following neoadjuvant chemotherapy were enrolled. DWI was performed on a 1.5 T system with b values of 0 and 750 s/mm. or on a 3 T system with b values of 0 and 800 or 0 and 1000 s/mm. The images on DCE-MRI alone, DWI alone, and DCE-MRI plus DWI were retrospectively reviewed. We evaluated the diagnostic performances of the three MRI protocols for the detection of residual cancer. The tumor size as predicted by MRI was compared with histopathologic findings. Apparent diffusion coefficient (ADC) values were also compared between the groups with and without residual cancer.

Results

Of the 78 patients, 59 (75.6%) had residual cancer. For detection of residual cancer, DCE-MRI plus DWI had higher specificity (80.0%), accuracy (91.0%), and PPV (93.2%) than DCE-MRI or DWI alone (P = 0.004, P = 0.007, and P = 0.034, respectively). The ICC values for residual cancer size between MRI and histopathology were 0.891 for DCE-MRI plus DWI, 0.792 for DCE-MRI, and 0.773 for DWI. ADC values showed no significant differences between residual cancer and chemotherapeutic changes (P = 0.130).

Conclusions

The addition of DWI to DCE-MRI significantly improved diagnostic performance in predicting pathologic response and residual breast cancer size after neoadjuvant chemotherapy.     

Diffusion-weighted MRI of the prostate at 3.0 T: Comparison of endorectal coil (ERC) MRI and phased-array coil (PAC) MRI—The impact of SNR on ADC measurement

Purpose

To compare ADC values measured from diffusion-weighted MR (DW-MR) images of the prostate obtained with both endorectal and phased-array coils (ERC + PAC) to those from DW-MRI images obtained with an eight-channel torso phased-array coil (PAC) at 3.0 T.

Methods

The institutional review board issued a waiver of informed consent for this HIPAA-compliant study. Twenty-five patients with biopsy-proven prostate cancer underwent standard 3-T MRI using 2 different coil arrangements (ERC + PAC and PAC only) in the same session. DW-MRI at five b-values (0, 600, 1000, 1200, and 1500 s/mm²) were acquired using both coil arrangements. On b = 0 images, signal-to-noise ratios (SNRs) were measured as the ratio of the mean signal from PZ and TZ ROIs to the standard deviation from the mean signal in an artifact-free ROI in the rectum. Matching regions-of-interest (ROIs) were identified in the peripheral zone and transition zone on ERC-MRI and PAC-MRI. For each ROI, mean ADC values for all zero and non-zero b-value combinations were computed.

Results

Mean SNR with ERC-MRI at PZ (66.33 ± 27.07) and TZ (32.69 ± 12.52) was 9.27 and 5.52 times higher than with PAC-MRI ((7.32 ± 2.30) and (6.13 ± 1.56), respectively) (P < 0.0001 for both). ADCs from DW-MR images obtained with all b-values in the PZ and TZ were significantly lower with PAC-MRI than with ERC-MRI (P < 0.001 for all).

Conclusion

Lower SNR of DW-MR images of the prostate obtained with a PAC can significantly decrease ADC values at higher b-values compared to similar measurements obtained using the ERC. To address these requirements, clinical MR systems should have image processing capabilities which incorporate the noise distribution.