Focal therapy with high-intensity focused ultrasound for prostate cancer: 3-year outcomes from a prospective trial.

OBJECTIVE: To assess the oncological and functional outcomes of focal high-intensity focused ultrasound (HIFU) in treating localised prostate cancer (PCa), a 3-year prospective study was undertaken using periodic post-ablation saturation biopsies. PATIENTS AND METHODS: Men with two or fewer lesions of grade group (GG) ≤3 PCa were eligible for participation. Additional criteria included a prostate-specific antigen (PSA) level of ≤15 ng/mL, clinical T1c-T2, and a life expectancy of ≥10 years. The primary endpoint was failure-free survival (FFS), defined as absence of clinically significant PCa (csPCa) in- or out-of-field on protocol-mandated saturation biopsy, no whole-gland or systemic salvage treatment, PCa metastasis, or PCa-related death. Results are reported using two distinct definitions of csPCa: (i) the presence of any GG ≥2 and (ii) any GG ≥3 or core involvement of ≥6 mm. Secondary endpoints were functional patient-reported outcome measures addressing urinary, sexual, and bowel function. RESULTS: A total of 91 patients were included: six (7%) with GG1 and 85 (93%) with GG ≥2. In all, 83 (91%) underwent at least one follow-up biopsy. Biopsy attendance at 6, 12, and 36 months was 84%, 67%, and 51%, respectively. The FFS at these time points for any GG ≥2 PCa was 79% (95% confidence interval [CI] 80-88%), 57% (95% CI 48-69%) and 44% (95% CI 34-56%), respectively. Using the second definition, FFS were 88% (95% CI 81-95%), 70% (95% CI 61-81%) and 65% (95% CI 55-77%), respectively. The 3-year cancer-specific survival was 100%, and freedom from metastasis was 99%. Magnetic resonance imaging (MRI) (negative predictive value of up to 89%, 95% CI 84-93%) and relative decrease of PSA values (P = 0.4) performed poorly in detecting residual disease. Urinary and bowel assessment returned to baseline questionnaire scores within 3 months. In all, 17 (21%) patients reported meaningful worsening in erectile function. A significant decrease of PCa related anxiety was observed. CONCLUSIONS: Focal HIFU treatment for localised PCa shows excellent functional outcomes with half of the patients remaining cancer-free after 3 years. Whole-gland treatment was avoided in 81%. Early follow-up biopsies are crucial to change or continue the treatment modality at the right time, while the use of MRI and PSA in detecting PCa recurrence is uncertain.

Dual-energy CT kidney stone characterization-can diagnostic accuracy be achieved at low radiation dose?

OBJECTIVES: To assess the accuracy of low-dose dual-energy computed tomography (DECT) to differentiate uric acid from non-uric acid kidney stones in two generations of dual-source DECT with stone composition analysis as the reference standard. METHODS: Patients who received a low-dose unenhanced DECT for the detection or follow-up of urolithiasis and stone extraction with stone composition analysis between January 2020 and January 2022 were retrospectively included. Collected stones were characterized using X-ray diffraction. Size, volume, CT attenuation, and stone characterization were assessed using DECT post-processing software. Characterization as uric acid or non-uric acid stones was compared to stone composition analysis as the reference standard. Sensitivity, specificity, and accuracy of stone classification were computed. Dose length product (DLP) and effective dose served as radiation dose estimates. RESULTS: A total of 227 stones in 203 patients were analyzed. Stone composition analysis identified 15 uric acid and 212 non-uric acid stones. Mean size and volume were 4.7 mm × 2.8 mm and 114 mm3, respectively. CT attenuation of uric acid stones was significantly lower as compared to non-uric acid stones (p < 0.001). Two hundred twenty-five of 227 kidney stones were correctly classified by DECT. Pooled sensitivity, specificity, and accuracy were 1.0 (95%CI: 0.97, 1.00), 0.93 (95%CI: 0.68, 1.00), and 0.99 (95%CI: 0.97, 1.00), respectively. Eighty-two of 84 stones with a diameter of ≤ 3 mm were correctly classified. Mean DLP was 162 ± 57 mGy*cm and effective dose was 2.43 ± 0.86 mSv. CONCLUSIONS: Low-dose dual-source DECT demonstrated high accuracy to discriminate uric acid from non-uric acid stones even at small stone sizes. KEY POINTS: • Two hundred twenty-five of 227 stones were correctly classified as uric acid vs. non-uric acid stones by low-dose dual-energy CT with stone composition analysis as the reference standard. • Pooled sensitivity, specificity, and accuracy for stone characterization were 1.0, 0.93, and 0.99, respectively. • Low-dose dual-energy CT for stone characterization was feasible in the majority of small stones < 3 mm.

Hot needles can confirm accurate lesion sampling intraoperatively using [18F]PSMA-1007 PET/CT-guided biopsy in patients with suspected prostate cancer.

PURPOSE: Prostate-specific membrane antigen (PSMA)-targeted PET is increasingly used for staging prostate cancer (PCa) with high accuracy to detect significant PCa (sigPCa). [68 Ga]PSMA-11 PET/MRI-guided biopsy showed promising results but also persisting limitation of sampling error, due to impaired image fusion. We aimed to assess the possibility of intraoperative quantification of [18F]PSMA-1007 PET/CT uptake in core biopsies as an instant confirmation for accurate lesion sampling. METHODS: In this IRB-approved, prospective, proof-of-concept study, we included five consecutive patients with suspected PCa. All underwent [18F]PSMA-1007 PET/CT scans followed by immediate PET/CT-guided and saturation template biopsy (3.1 ± 0.3 h after PET). The activity in biopsy cores was measured as counts per minute (cpm) in a gamma spectrometer. Pearson's test was used to correlate counts with histopathology (WHO/ISUP), tumor length, and membranous PSMA expression on immunohistochemistry (IHC). RESULTS: In 43 of 113 needles, PCa was present. The mean cpm was overall significantly higher in needles with PCa (263 ± 396 cpm) compared to needles without PCa (73 ± 44 cpm, p < 0.001). In one patient with moderate PSMA uptake (SUVmax 8.7), 13 out of 24 needles had increased counts (100-200 cpm) but only signs of inflammation and PSMA expression in benign glands on IHC. Excluding this case, ROC analysis resulted in an AUC of 0.81, with an optimal cut-off to confirm PCa at 75 cpm (sens/spec of 65.1%/87%). In all 4 patients with PCa, the first or second PSMA PET-guided needle was positive for sigPCa with high counts (156-2079 cpm). CONCLUSIONS: [18F]PSMA-1007 uptake in PCa can be used to confirm accurate lesion sampling of the dominant tumor intraoperatively. This technique could improve confidence in imaging-based biopsy guidance and reduce the need for saturation biopsy. TRIAL REGISTRATION NUMBER: NCT03187990, 15/06/2017.

Diagnostic performance of 68Ga-PSMA-11 PET/MRI-guided biopsy in patients with suspected prostate cancer: a prospective single-center study.

PURPOSE: Ultrasound-guided biopsy (US biopsy) with 10-12 cores has a suboptimal sensitivity for clinically significant prostate cancer (sigPCa). If US biopsy is negative, magnetic resonance imaging (MRI)-guided biopsy is recommended, despite a low specificity for lesions with score 3-5 on Prostate Imaging Reporting and Data System (PIRADS). Screening and biopsy guidance using an imaging modality with high accuracy could reduce the number of unnecessary biopsies, reducing side effects. The aim of this study was to assess the performance of positron emission tomography/MRI with 68Ga-labeled prostate-specific membrane antigen (PSMA-PET/MRI) to detect and localize primary sigPCa (ISUP grade group 3 and/or cancer core length ≥ 6 mm) and guide biopsy. METHODS: Prospective, open-label, single-center, non-randomized, diagnostic accuracy study including patients with suspected PCa by elevation of prostate-specific antigen (PSA) level and a suspicious lesion (PIRADS ≥3) on multiparametric MRI (mpMRI). Forty-two patients underwent PSMA-PET/MRI followed by both PSMA-PET/MRI-guided and section-based saturation template biopsy between May 2017 and February 2019. Primary outcome was the accuracy of PSMA-PET/MRI for biopsy guidance using section-based saturation template biopsy as the reference standard. RESULTS: SigPCa was found in 62% of the patients. Patient-based sensitivity, specificity, negative and positive predictive value, and accuracy for sigPCa were 96%, 81%, 93%, 89%, and 90%, respectively. One patient had PSMA-negative sigPCa. Eight of nine false-positive lesions corresponded to cancer on prostatectomy and one in six false-negative lesions was negative on prostatectomy. CONCLUSION: PSMA-PET/MRI has a high accuracy for detecting sigPCa and is a promising tool to select patients with suspicion of PCa for biopsy. TRIAL REGISTRATION: This trial was retrospectively registered under the name "Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) Guided Biopsy in Men with Elevated PSA" (NCT03187990) on 06/15/2017 ( https://clinicaltrials.gov/ct2/show/NCT03187990 ).

[PI-RADS 2.1 and structured reporting of magnetic resonance imaging of the prostate]. / PI-RADS 2.1 und strukturierte Befundung der Magnetresonanztomographie der Prostata.

CLINICAL/METHODOLOGICAL ISSUE: The detection of clinically significant prostate cancers while simultaneously avoiding over-diagnosing tumors with low malignant potential is a challenge in clinical practice. STANDARD RADIOLOGICAL METHODS: Multiparametric prostate magnetic resonance imaging (MRI) in accordance with the Prostate Imaging Reporting and Data System (PI-RADS) guidelines is accepted as standard-of-care with both urologists and radiologists. METHODOLOGICAL INNOVATIONS: The PI-RADS guidelines have been updated to version 2.1, including revised technical recommendations and changes to the scoring of lesions. PERFORMANCE: The PI-RADS guidelines have had great impact on the standardization of multiparametric prostate MRI and offer templates for structured reporting. This simplifies communication with the referring physician. ACHIEVEMENTS: The new version 2.1 of the guidelines represents an evolutionary improvement of the widely accepted version 2.0. Several aspects of reporting have been revised-however, some pre-known limitations persist, which will require further refinement in the future.

External Validation and Comparison of Prostate Cancer Risk Calculators Incorporating Multiparametric Magnetic Resonance Imaging for Prediction of Clinically Significant Prostate Cancer.

PURPOSE: We sought to externally validate recently published prostate cancer risk calculators incorporating multiparametric magnetic resonance imaging to predict clinically significant prostate cancer. We also compared the performance of these calculators to that of multiparametric magnetic resonance imaging naïve prostate cancer risk calculators. MATERIALS AND METHODS: We identified men without a previous prostate cancer diagnosis who underwent transperineal template saturation prostate biopsy with fusion guided targeted biopsy between November 2014 and March 2018 at our academic tertiary referral center. Any Gleason pattern 4 or greater was defined as clinically significant prostate cancer. Predictors, which were patient age, prostate specific antigen, digital rectal examination, prostate volume, family history, previous prostate biopsy and the highest region of interest according to the PI-RADS™ (Prostate Imaging Reporting and Data System), were retrospectively collected. Four multiparametric magnetic resonance imaging prostate cancer risk calculators and 2 multiparametric magnetic resonance imaging naïve prostate cancer risk calculators were evaluated for discrimination, calibration and the clinical net benefit using ROC analysis, calibration plots and decision curve analysis. RESULTS: Of the 468 men 193 (41%) were diagnosed with clinically significant prostate cancer. Three multiparametric magnetic resonance imaging prostate cancer risk calculators showed similar discrimination with a ROC AUC significantly higher than that of the other prostate cancer risk calculators (AUC 0.83-0.85 vs 0.69-0.74). Calibration in the large showed 2% deviation from the true amount of clinically significant prostate cancer for 2 multiparametric magnetic resonance imaging risk calculators while the other calculators showed worse calibration at 11% to 27%. A clinical net benefit was observed only for 3 multiparametric magnetic resonance imaging risk calculators at biopsy thresholds of 15% or greater. None of the 6 investigated prostate cancer risk calculators demonstrated clinical usefulness against a biopsy all strategy at thresholds less than 15%. CONCLUSIONS: The performance of multiparametric magnetic resonance imaging prostate cancer risk calculators varies but they generally outperform multiparametric magnetic resonance imaging naïve prostate cancer risk calculators in regard to discrimination, calibration and clinical usefulness. External validation in other biopsy settings is highly encouraged.

Does quantitative assessment of arterial phase hyperenhancement and washout improve LI-RADS v2018-based classification of liver lesions?

OBJECTIVES: To compare interreader agreement and diagnostic accuracy of LI-RADS v2018 categorization using quantitative versus qualitative MRI assessment of arterial phase hyperenhancement (APHE) and washout (WO) of focal liver lesions. METHODS: Sixty patients (19 female; mean age, 56 years) at risk for HCC with 71 liver lesions (28 HCCs, 43 benign) who underwent contrast-enhanced MRI were included in this retrospective study. Four blinded radiologists independently assigned a qualitative LI-RADS score per lesion. Two other radiologists placed ROIs within the lesion, adjacent liver parenchyma, and paraspinal musculature on pre- and post-contrast MR images. The percentage of arterial enhancement and the liver-to-lesion contrast ratio were calculated for quantification of APHE and WO. Using these quantitative parameters, a quantitative LI-RADS score was assigned. Interreader agreement and AUCs were calculated. RESULTS: Interreader agreement was similar for qualitative and quantitative LI-RADS (κ = 0.38 vs. 0.40-0.47) with a tendency towards improved agreement for quantitatively assessed APHE (κ = 0.65 vs. 0.81) and WO (κ = 0.53 vs. 0.78). Qualitative LI-RADS showed an AUC of 0.86, 0.94, 0.94, and 0.91 for readers 1, 2, 3, and 4, respectively. The quantitative LI-RADS score where APHE/WO/or both were replaced showed an AUC of 0.89/0.84/0.89, 0.95/0.92/0.92, 0.93/0.91/0.89, and 0.91/0.86/0.88 for readers 1, 2, 3, and 4, respectively. Sensitivity of LR-4/5 slightly increased, while specificity slightly decreased using quantitative APHE. CONCLUSION: Qualitative and quantitative LI-RADS showed similar performance. Quantitatively assessed APHE showed the potential to increase interreader agreement and sensitivity of HCC diagnosis, whereas quantitatively assessed WO had the opposite effect and needs to be redefined. KEY POINTS: • Quantitative assessment of arterial phase hyperenhancement shows the potential to increase interreader agreement and sensitivity to diagnose hepatocellular carcinoma. • Adding quantitative measurements of major LI-RADS features does not improve accuracy over qualitative assessment alone according to the LI-RADS v2018 algorithm.

Manual prostate cancer segmentation in MRI: interreader agreement and volumetric correlation with transperineal template core needle biopsy.

OBJECTIVES: To assess interreader agreement of manual prostate cancer lesion segmentation on multiparametric MR images (mpMRI). The secondary aim was to compare tumor volume estimates between MRI segmentation and transperineal template saturation core needle biopsy (TTSB). METHODS: We retrospectively reviewed patients who had undergone mpMRI of the prostate at our institution and who had received TTSB within 190 days of the examination. Seventy-eight cancer lesions with Gleason score of at least 3 + 4 = 7 were manually segmented in T2-weighted images by 3 radiologists and 1 medical student. Twenty lesions were also segmented in apparent diffusion coefficient (ADC) and dynamic contrast enhanced (DCE) series. First, 20 volumetric similarity scores were computed to quantify interreader agreement. Second, manually segmented cancer lesion volumes were compared with TTSB-derived estimates by Bland-Altman analysis and Wilcoxon testing. RESULTS: Interreader agreement across all readers was only moderate with mean T2 Dice score of 0.57 (95%CI 0.39-0.70), volumetric similarity coefficient of 0.74 (0.48-0.89), and Hausdorff distance of 5.23 mm (3.17-9.32 mm). Discrepancy of volume estimate between MRI and TTSB was increasing with tumor size. Discrepancy was significantly different between tumors with a Gleason score 3 + 4 vs. higher grade tumors (0.66 ml vs. 0.78 ml; p = 0.007). There were no significant differences between T2, ADC, and DCE segmentations. CONCLUSIONS: We found at best moderate interreader agreement of manual prostate cancer segmentation in mpMRI. Additionally, our study suggests a systematic discrepancy between the tumor volume estimate by MRI segmentation and TTSB core length, especially for large and high-grade tumors. KEY POINTS: • Manual prostate cancer segmentation in mpMRI shows moderate interreader agreement. • There are no significant differences between T2, ADC, and DCE segmentation agreements. • There is a systematic difference between volume estimates derived from biopsy and MRI.

Dynamic contrast enhancement in prostate MRI as predictor of erectile function and recovery after radical prostatectomy.

PURPOSE: To analyze routine preoperative prostate MRI to predict erectile function (EF) before and after radical prostatectomy (RP). METHODS: Patients who underwent RP with an existing preoperative MRI including dynamic contrast-enhanced images and completed International Index of Erectile Function (IIEF-5) questionnaires at baseline and 12 months postoperative. They were divided into four erectile dysfunction (ED) groups according to preoperative IIEF-5 score. The perfusion quality was measured in the peripheral zone of the prostate by the ratio of signal increase 120 s after wash-in of contrast agent (Ratio120) in preoperative MRI and compared between the ED groups. RESULTS: Ratio120 showed differences among the preoperative ED groups (p = .020) in 97 patients. According to IIEF-5 at 12 months postoperative, 43 patients were dichotomized into "no to mild" (≥17 points) and "moderate to severe" (≤16) ED groups. Ratio120 revealed differences among the postoperative ED groups (128.84% vs. 101.95%; p = .029) and stayed an independent predictor for ED in the multivariable regression analysis (adjusted for age, nerve-sparing and preoperative IIEF-5). ROC curves demonstrated an additional diagnostic benefit. CONCLUSIONS: Preoperative MRI of the prostate may be used for the prediction of EF and postsurgical recovery after RP. This may serve as important tool in preoperative patient counseling and management of expectations.

[Diagnosis and Minimal Invasive Treatment of Benign Prostatic Hyperplasia]. / Diagnostik und interventionell-radiologische Therapie der benignen Prostatahyperplasie.

Diagnosis and Minimal Invasive Treatment of Benign Prostatic Hyperplasia Abstract. Benign prostatic hyperplasia (BPH) is a common condition in men aged 50 - 60 years with a prevalence of about 50 %. After failure of conservative treatment, the standard treatment of BPH is transurethral resection of the prostate (TURP). However, over the last years prostatic artery embolization (PAE) emerged as a minimal invasive alternative to treat lower urinary tract symptoms. After patient assessment by MRI and CT of the prostate to rule out possible contraindications of PAE, the procedure can be performed in an outpatient setting under local anesthesia by an interventional radiologist. Especially for frail patients and / or patients with special risks regarding surgery / anesthesia, PAE may be an alternative to TURP with fewer complications.

Diagnostic Accuracy of Multiparametric MRI versus 68Ga-PSMA-11 PET/MRI for Extracapsular Extension and Seminal Vesicle Invasion in Patients with Prostate Cancer.

Background Recent studies have reported the additive value of combined gallium 68 (68Ga)-labeled Glu-urea-Lys (Ahx)-HBED-CC ligand targeting the prostate-specific membrane antigen (PSMA) (hereafter called 68Ga-PSMA-11) PET/MRI for the detection and localization of primary prostate cancer compared with multiparametric MRI. Purpose To compare the diagnostic accuracy and interrater agreement of multiparametric MRI and 68Ga-PSMA-11 PET/MRI for the detection of extracapsular extension (ECE) and seminal vesicle infiltration (SVI) in patients with prostate cancer. Materials and Methods Retrospective analysis of 40 consecutive men who underwent multiparametric MRI and 68Ga-PSMA-11 PET/MRI within 6 months for suspected prostate cancer followed by radical prostatectomy between April 2016 and July 2018. Four readers blinded to clinical and histopathologic findings rated the probability of ECE and SVI at multiparametric MRI and PET/MRI by using a five-point Likert-type scale. The prostatectomy specimen served as the reference standard. Accuracy was assessed with a multireader multicase analysis and by calculating reader-average areas under the receiver operating characteristics curve (AUCs), sensitivity, and specificity for ordinal and dichotomized data in a region-specific and patient-specific approach. Interrater agreement was assessed with the Fleiss multirater κ. Results For multiparametric MRI versus PET/MRI in ECE detection, respectively, AUC, sensitivity, and specificity in the region-specific analysis were 0.67 and 0.75 (P = .07), 28% (21 of 76) and 47% (36 of 76) (P = .09), and 94% (529 of 564) and 90% (509 of 564) (P = .007). For the patient-specific analysis, AUC, sensitivity, and specificity were 0.66 and 0.73 (P = .19), 46% (22 of 48) and 69% (33 of 48) (P = .04), and 75% (84 of 112) and 67% (75 of 112) (P = .19), respectively. For multiparametric MRI versus PET/MRI in SVI detection, respectively, AUC, sensitivity, and specificity of the region-specific analysis were 0.66 and 0.74 (P = .21), 35% (seven of 20) and 50% (10 of 20) (P = .25), and 98% (295 of 300) and 94% (282 of 300) (P < .001). For the patient-specific analysis, AUC, sensitivity, and specificity were 0.65 and 0.79 (P = .25), 35% (seven of 20) and 55% (11 of 20) (P = .20), and 98% (137 of 140) and 94% (131 of 140) (P = .07), respectively. Interrater reliability for multiparametric MRI versus PET/MRI did not differ for ECE (κ, 0.46 vs 0.40; P = .24) and SVI (κ, 0.23 vs 0.33; P = .39). Conclusion Our results suggest that gallium 68 (68Ga)-labeled Glu-urea-Lys (Ahx)-HBED-CC ligand targeting the prostate-specific membrane antigen (PSMA) (68Ga-PSMA-11) PET/MRI and multiparametric MRI perform similarly for local staging of prostate cancer in patients with intermediate-to-high-risk prostate cancer. The increased sensitivity of 68Ga-PSMA-11 PET/MRI for the detection of extracapsular disease comes at the cost of a slightly reduced specificity. © RSNA, 2019.

Extensive Histological Sampling following Focal Therapy of Clinically Significant Prostate Cancer with High Intensity Focused Ultrasound.

PURPOSE: Clinically significant, localized prostate cancer is currently treated with whole gland therapy. This approach is effective but associated with genitourinary and rectal side effects. Focal therapy of prostate cancer has been proposed as an alternative. The aim of this study was to determine the oncologic and functional outcomes of focal high intensity focused ultrasound therapy of prostate cancer. MATERIALS AND METHODS: In this single center, prospective study 75 men were treated between April 2014 and April 2018. Multiparametric magnetic resonance imaging and transperineal template saturation prostate biopsy were performed to localize prostate cancer, followed by focal ablation with high intensity focused ultrasound. The study primary end point was the detection of clinically significant prostate cancer, defined as Gleason score 7 or greater, at 6-month followup transperineal template saturation prostate biopsy. Genitourinary side effects were of secondary interest. RESULTS: Median patient age was 67 years (IQR 60-71) and median prostate specific antigen was 5.87 ng/ml (IQR 4.65-7.44). There were 5 low risk (6.7%) and 70 intermediate risk (93.3%) cancers. Clinically significant prostate cancer was detected in 41% of the men (95% CI 30.3-53.0) who underwent biopsy at 6 months and the median number of sampled cores was 44 (IQR 36-44). Prostate specific antigen (OR 1.17, IQR 0.49-2.85, p=0.71) and multiparametric magnetic resonance imaging (14.3% sensitivity, IQR 6.7-31.5) performed poorly to predict positive biopsies. Pad-free continence and erection sufficient for penetration were preserved in 63 of 64 (98.4%) and 31 of 45 patients (68.9%), respectively. CONCLUSIONS: Focal therapy with high intensity focused ultrasound leads to a low rate of genitourinary side effects. Followup biopsy of treated and untreated prostates remains the only modality to adequately select men in need of early salvage treatment.

Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging and Fusion Guided Targeted Biopsy Evaluated by Transperineal Template Saturation Prostate Biopsy for the Detection and Characterization of Prostate Cancer.

PURPOSE: We evaluated the diagnostic accuracy of multiparametric magnetic resonance imaging and multiparametric magnetic resonance imaging/transrectal ultrasound fusion guided targeted biopsy against that of transperineal template saturation prostate biopsy to detect prostate cancer. MATERIALS AND METHODS: We retrospectively analyzed the records of 415 men who consecutively presented for prostate biopsy between November 2014 and September 2016 at our tertiary care center. Multiparametric magnetic resonance imaging was performed using a 3 Tesla device without an endorectal coil, followed by transperineal template saturation prostate biopsy with the BiopSee® fusion system. Additional fusion guided targeted biopsy was done in men with a suspicious lesion on multiparametric magnetic resonance imaging, defined as Likert score 3 to 5. Any Gleason pattern 4 or greater was defined as clinically significant prostate cancer. The detection rates of multiparametric magnetic resonance imaging and fusion guided targeted biopsy were compared with the detection rate of transperineal template saturation prostate biopsy using the McNemar test. RESULTS: We obtained a median of 40 (range 30 to 55) and 3 (range 2 to 4) transperineal template saturation prostate biopsy and fusion guided targeted biopsy cores, respectively. Of the 124 patients (29.9%) without a suspicious lesion on multiparametric magnetic resonance imaging 32 (25.8%) were found to have clinically significant prostate cancer on transperineal template saturation prostate biopsy. Of the 291 patients (70.1%) with a Likert score of 3 to 5 clinically significant prostate cancer was detected in 129 (44.3%) by multiparametric magnetic resonance imaging fusion guided targeted biopsy, in 176 (60.5%) by transperineal template saturation prostate biopsy and in 187 (64.3%) by the combined approach. Overall 58 cases (19.9%) of clinically significant prostate cancer would have been missed if fusion guided targeted biopsy had been performed exclusively. The sensitivity of multiparametric magnetic resonance imaging and fusion guided targeted biopsy for clinically significant prostate cancer was 84.6% and 56.7% with a negative likelihood ratio of 0.35 and 0.46, respectively. CONCLUSIONS: Multiparametric magnetic resonance imaging alone should not be performed as a triage test due to a substantial number of false-negative cases with clinically significant prostate cancer. Systematic biopsy outperformed fusion guided targeted biopsy. Therefore, it will remain crucial in the diagnostic pathway of prostate cancer.

Detection of Clinically Significant Prostate Cancer: Short Dual-Pulse Sequence versus Standard Multiparametric MR Imaging-A Multireader Study.

Purpose To compare the diagnostic performance of a short dual-pulse sequence magnetic resonance (MR) imaging protocol versus a standard six-pulse sequence multiparametric MR imaging protocol for detection of clinically significant prostate cancer. Materials and Methods This HIPAA-compliant study was approved by the regional ethics committee. Between July 2013 and March 2015, 63 patients from a prospectively accrued study population who underwent MR imaging of the prostate including transverse T1-weighted; transverse, coronal, and sagittal T2-weighted; diffusion-weighted; and dynamic contrast material-enhanced MR imaging with a 3-T imager at a single institution were included in this retrospective study. The short MR imaging protocol image set consisted of transverse T2-weighted and diffusion-weighted images only. The standard MR imaging protocol image set contained images from all six pulse sequences. Three expert readers from different institutions assessed the likelihood of prostate cancer on a five-point scale. Diagnostic performance on a quadrant basis was assessed by using areas under the receiver operating characteristic curves, and differences were evaluated by using 83.8% confidence intervals. Intra- and interreader agreement was assessed by using the intraclass correlation coefficient. Transperineal template saturation biopsy served as the standard of reference. Results At histopathologic evaluation, 84 of 252 (33%) quadrants were positive for cancer in 38 of 63 (60%) men. There was no significant difference in detection of tumors larger than or equal to 0.5 mL for any of the readers of the short MR imaging protocol, with areas under the curve in the range of 0.74-0.81 (83.8% confidence interval [CI]: 0.64, 0.89), and for readers of the standard MR imaging protocol, areas under the curve were 0.71-0.77 (83.8% CI: 0.62, 0.86). Ranges for sensitivity were 0.76-0.95 (95% CI: 0.53, 0.99) and 0.76-0.86 (95% CI: 0.53, 0.97) and those for specificity were 0.84-0.90 (95% CI: 0.79, 0.94) and 0.82-0.90 (95% CI: 0.77, 0.94) for the short and standard MR protocols, respectively. Ranges for interreader agreement were 0.48-0.60 (83.8% CI: 0.41, 0.66) and 0.49-0.63 (83.8% CI: 0.42, 0.68) for the short and standard MR imaging protocols. Conclusion For the detection of clinically significant prostate cancer, no difference was found in the diagnostic performance of the short MR imaging protocol consisting of only transverse T2-weighted and diffusion-weighted imaging pulse sequences compared with that of a standard multiparametric MR imaging protocol. © RSNA, 2017 Online supplemental material is available for this article.

Comparison of Intravoxel Incoherent Motion Parameters across MR Imagers and Field Strengths: Evaluation in Upper Abdominal Organs.

Purpose To determine the reproducibility of intravoxel incoherent motion (IVIM) parameters measured in upper abdominal organs with magnetic resonance (MR) imagers from different vendors and with different field strengths. Materials and Methods This prospective study was approved by the independent ethics committees of Kanton Bern and Kanton Zurich, and signed informed consent was obtained from all participants. Abdominal diffusion-weighted images in 10 healthy men (mean age, 37 years ± 8 [standard deviation]) were acquired by using 1.5- and 3.0-T MR imagers from three different vendors. Two readers independently delineated regions of interest that were used to measure IVIM parameters (diffusion coefficient [Dt], perfusion fraction [Fp], and pseudodiffusion coefficient [Dp]) in the left and right lobes of the liver, and in the pancreas, spleen, renal cortex, and renal medulla. Measurement reproducibility between readers was assessed with intraclass correlation coefficients (ICCs). Variability across MR imagers was analyzed by using between- and within-subject coefficients of variation (CVs) and analysis of variance (ANOVA). Results Between-reader reproducibility was high for Dt (ICC, 94.6%), intermediate for Fp (ICC, 81.7%), and low for Dp (ICC, 69.5%). Between- and within-subject CVs of Dt were relatively high (>20%) in the left lobe of the liver and relatively low (<10%) in the renal cortex and renal medulla. CVs generally exceeded 15% for Fp values and 20% for Dp. ANOVA indicated significant differences (P < .05) between MR imagers. Conclusion IVIM parameters in the upper abdomen may differ substantially across MR imagers. (©) RSNA, 2015 Online supplemental material is available for this article.

Impact of the calculation algorithm on biexponential fitting of diffusion-weighted MRI in upper abdominal organs.

PURPOSE: To compare the variability, precision, and accuracy of six different algorithms (Levenberg-Marquardt, Trust-Region, Fixed-Dp , Segmented-Unconstrained, Segmented-Constrained, and Bayesian-Probability) for computing intravoxel-incoherent-motion-related parameters in upper abdominal organs. METHODS: Following the acquisition of abdominal diffusion-weighted magnetic resonance images of 10 healthy men, six distinct algorithms were employed to compute intravoxel-incoherent-motion-related parameters in the left and right liver lobe, pancreas, spleen, renal cortex, and renal medulla. Algorithms were evaluated regarding inter-reader and intersubject variability. Comparability of results was assessed by analyses of variance. The algorithms' precision and accuracy were investigated on simulated data. RESULTS: A Bayesian-Probability based approach was associated with very low inter-reader variability (average Intraclass Correlation Coefficients: 96.5-99.6%), the lowest inter-subject variability (Coefficients of Variation [CV] for the pure diffusion coefficient Dt : 3.8% in the renal medulla, 6.6% in the renal cortex, 10.4-12.1% in the left and right liver lobe, 15.3% in the spleen, 15.8% in the pancreas; for the perfusion fraction Fp : 15.5% on average; for the pseudodiffusion coefficient Dp : 25.8% on average), and the highest precision and accuracy. Results differed significantly (P < 0.05) across algorithms in all anatomical regions. CONCLUSION: The Bayesian-Probability algorithm should be preferred when computing intravoxel-incoherent-motion-related parameters in upper abdominal organs.

Systematic analysis of the intravoxel incoherent motion threshold separating perfusion and diffusion effects: Proposal of a standardized algorithm.

PURPOSE: To systematically evaluate the dependence of intravoxel-incoherent-motion (IVIM) parameters on the b-value threshold separating the perfusion and diffusion compartment, and to implement and test an algorithm for the standardized computation of this threshold. METHODS: Diffusion weighted images of the upper abdomen were acquired at 3 Tesla in eleven healthy male volunteers with 10 different b-values and in two healthy male volunteers with 16 different b-values. Region-of-interest IVIM analysis was applied to the abdominal organs and skeletal muscle with a systematic increase of the b-value threshold for computing pseudodiffusion D*, perfusion fraction Fp, diffusion coefficient D, and the sum of squared residuals to the bi-exponential IVIM-fit. RESULTS: IVIM parameters strongly depended on the choice of the b-value threshold. The proposed algorithm successfully provided optimal b-value thresholds with the smallest residuals for all evaluated organs [s/mm2]: e.g., right liver lobe 20, spleen 20, right renal cortex 150, skeletal muscle 150. Mean D* [10(-3) mm(2)/s], Fp [%], and D [10(-3) mm(2)/s] values (±standard deviation) were: right liver lobe, 88.7 ± 42.5, 22.6 ± 7.4, 0.73 ± 0.12; right renal cortex: 11.5 ± 1.8, 18.3 ± 2.9, 1.68 ± 0.05; spleen: 41.9 ± 57.9, 8.2 ± 3.4, 0.69 ± 0.07; skeletal muscle: 21.7 ± 19.0; 7.4 ± 3.0; 1.36 ± 0.04. CONCLUSION: IVIM parameters strongly depend upon the choice of the b-value threshold used for computation. The proposed algorithm may be used as a robust approach for IVIM analysis without organ-specific adaptation.

Molecular imaging of prostate cancer: translating molecular biology approaches into the clinical realm.

UNLABELLED: The epidemiology of prostate cancer has dramatically changed since the introduction of prostate-specific antigen (PSA) screening in the 1980's. Most prostate cancers today are detected at early stages of the disease and are considered 'indolent'; however, some patients' prostate cancers demonstrate a more aggressive behaviour which leads to rapid progression and death. Increasing understanding of the biology underlying the heterogeneity that characterises this disease has led to a continuously evolving role of imaging in the management of prostate cancer. Functional and metabolic imaging techniques are gaining importance as the impact on the therapeutic paradigm has shifted from structural tumour detection alone to distinguishing patients with indolent tumours that can be managed conservatively (e.g., by active surveillance) from patients with more aggressive tumours that may require definitive treatment with surgery or radiation. In this review, we discuss advanced imaging techniques that allow direct visualisation of molecular interactions relevant to prostate cancer and their potential for translation to the clinical setting in the near future. The potential use of imaging to follow molecular events during drug therapy as well as the use of imaging agents for therapeutic purposes will also be discussed. KEY POINTS: • Advanced imaging techniques allow direct visualisation of molecular interactions in prostate cancer. • MRI/PET, optical and Cerenkov imaging facilitate the translation of molecular biology. • Multiple compounds targeting PSMA expression are currently undergoing clinical translation. • Other targets (e.g., PSA, prostate-stem cell antigen, GRPR) are in development.

Interreader and inter-test agreement in assessing treatment response following transarterial embolization for hepatocellular carcinoma.

PURPOSE: To evaluate interreader and inter-test agreement in applying size- and necrosis-based response assessment criteria after transarterial embolization (TAE) for hepatocellular carcinoma (HCC), applying two different methods of European Association for the Study of the Liver (EASL) criteria. METHODS: Seventy-four patients (median age, 67 years) from a prospectively accrued study population were included in this retrospective study. Four radiologists independently evaluated CT data at 2-3 (1st follow-up, FU) and 10-12 (2nd FU) weeks after TAE and assessed treatment response using size-based (WHO, RECIST) and necrosis-based (mRECIST, EASL) criteria. Enhancing tissue was bidimensionally measured (EASLmeas) and also visually estimated (EASLest). Interreader and inter-test agreements were assessed using intraclass correlation coefficient (ICC) and κ statistics. RESULTS: Interreader agreement for all response assessment methods ranged from moderate to substantial (κ = 0.578-0.700) at 1st FU and was substantial (κ = 0.716-0.780) at 2nd FU. Inter-test agreement was substantial between WHO and RECIST (κ = 0.610-0.799, 1st FU; κ = 0.655-0.782, 2nd FU) and excellent between EASLmeas and EASLest (κ = 0.899-0.918, 1st FU; κ = 0.843-0.877, 2nd FU). CONCLUSION: Size- and necrosis-based criteria both show moderate to excellent interreader agreement in evaluating treatment response after TAE for HCC. Inter-test agreement regarding EASLmeas and EASLest was excellent, suggesting that either may be used. KEY POINTS: • Applying EASL criteria, visual estimation and bidimensional measurements show comparable interreader agreement. • EASL meas and EASL est show substantial interreader agreement for treatment response in HCC. • Agreement was excellent for EASL meas and EASL est after TAE of HCC. • Visual estimation of enhancement is adequate to assess treatment response of HCC.

The Potential Impact of Functional Imaging on Decision Making and Outcome in Patients Undergoing Surgical Revascularization.

OBJECTIVE: Coronary angiography (CA) remains the standard for preoperative planning for surgical revascularization. However, besides anatomical imaging, current guidelines recommend additional functional imaging before a therapy decision is made. We assess the impact of functional imaging on the strategy of coronary artery bypass grafting (CABG) with particular regards on postoperative patency and myocardial perfusion. METHODS: After CA, 55 patients (47 males/8 females; age: 65.1 ± 9.5 years) underwent perfusion cardiovascular magnetic resonance (CMR) and dual-source computed tomography (DSCT) before isolated CABG (n = 31), CABG and concomitant valve surgery (valve + CABG; n = 10) and isolated valve surgery (n = 14; control). DSCT was used for analysis of significant stenosis, CMR for myocardial-perfusion to discriminate between: no ischemia (normal), ischemia, or scar. The results, unknown to the surgeons, were compared with CA and related to the location and number of distal anastomoses. Nineteen CABG patients underwent follow-up CMR and DSCT (FU: 13 ± 3 months) to compare the preop findings with the postop outcomes. RESULTS: Thirty-nine patients either received CABG alone (n = 31) or a combined procedure (n = 10) with a total of 116 distal anastomoses. DSCT was compared with CA regarding accuracy of coronary stenosis and showed 91% sensitivity, 88% specificity, and negative/positive predictive values of 89/90%. In total, 880 myocardial segments (n = 55, 16 segments/patient) were assessed by CMR. In 17% (149/880) of segments ischemia and in 8% (74/880) scar tissue was found. Interestingly, 14% (16/116) of bypass-anastomoses were placed on non-ischemic myocardium and 3% (4/116) on scar tissue. In a subgroup of 19 patients 304 segments were evaluated. Thirty-nine percent (88/304) of all segments showed ischemia preoperatively, while 94% (83/88) of these ischemic segments did not show any ischemia postoperatively. In regard to performed anastomoses, 79% of all grafts (49/62) were optimally placed, whereas 21% (13/62) were either placed into non-ischemic myocardium or scar tissue, including 10% occluded grafts (6/62). CONCLUSION: In the whole cohort analysis, 17% of grafts were placed in regions with either no ischemia or scar tissue. The subgroup analysis revealed that 94% of all ischemic segments were successfully revascularized after CABG. Thus, functional imaging could be a promising tool in preoperative planning of revascularization strategy. Avoidance of extensive and unnecessary grafting could further optimize outcomes after CABG.