Endovascular simulation training: a tool to increase enthusiasm for interventional radiology among medical students.

OBJECTIVES: Interventional radiology (IR) is a growing field but is underrepresented in most medical school curricula. We tested whether endovascular simulator training improves medical students' attitudes towards IR. MATERIALS AND METHODS: We conducted this prospective study at two university medical centers; overall, 305 fourth-year medical students completed a 90-min IR course. The class consisted of theoretical and practical parts involving endovascular simulators. Students completed questionnaires before the course, after the theoretical and after the practical part. On a 7-point Likert scale, they rated their interest in IR, knowledge of IR, attractiveness of IR, and the likelihood to choose IR as subspecialty. We used a crossover design to prevent position-effect bias. RESULTS: The seminar/simulator parts led to the improvement for all items compared with baseline: interest in IR (pre-course 5.2 vs. post-seminar/post-simulator 5.5/5.7), knowledge of IR (pre-course 2.7 vs. post-seminar/post-simulator 5.1/5.4), attractiveness of IR (pre-course 4.6 vs. post-seminar/post-simulator 4.8/5.0), and the likelihood of choosing IR as a subspecialty (pre-course 3.3 vs. post-seminar/post-simulator 3.8/4.1). Effect was significantly stronger for simulator training compared with that for seminar for all items (p < 0.05). For simulator training, subgroup analysis of students with pre-existing positive attitude showed considerable improvement regarding "interest in IR" (× 1.4), "knowledge of IR" (× 23), "attractiveness of IR" (× 2), and "likelihood to choose IR" (× 3.2) compared with pretest. CONCLUSION: Endovascular simulator training significantly improves students' attitude towards IR regarding all items. Implementing such courses at a very early stage in the curriculum should be the first step to expose medical students to IR and push for IR. KEY POINTS: • Dedicated IR-courses have a significant positive effect on students' attitudes towards IR. • Simulator training is superior to a theoretical seminar in positively influencing students' attitudes towards IR. • Implementing dedicated IR courses in medical school might ease recruitment problems in the field.

Optimising the number of cores for magnetic resonance imaging-guided targeted and systematic transperineal prostate biopsy.

OBJECTIVES: To assess cancer detection rates of different target-dependent transperineal magnetic resonance (MR)/ultrasonography (US) fusion-guided biopsy templates with reduced number of systematic cores. PATIENTS AND METHODS: Single-centre outcome of transperineal MR/US fusion-guided biopsies of 487 men with a single target MR imaging (MRI) lesion, prospectively collected between 2012 and 2016. All men underwent transperineal targeted biopsy (TB) with two cores, followed by 18-24 systematic sector biopsies (SB) using the Ginsburg protocol. Gleason score ≥7 prostate cancer detection rates for two-core TB, four-core extended TB (eTB), 10- to 20-core saturation TB (sTB) including cores from sectors adjacent to the target, and 14 core ipsilateral TB (iTB) were compared to combined TB+SB. RESULTS: Cancer was detected in 345 men and Gleason score 7-10 cancer in 211 men. TB alone detected 67%, eTB 76%, sTB 91% and iTB 91% of these Gleason score 7-10 cancers. In the subgroup of 33 men (7% of cohort) with an anterior >0.5 mL highly suspicious MRI lesion and a prostate volume ≤45 mL, four-core eTB detected 31 of 32 cancers (97%) and all 26 Gleason score 7-10 cancers. CONCLUSION: sTB detected Gleason score 7-10 cancer in 25% more of the men than a two-core TB approach, and in almost as many men (91%) as the 20-26-core combined TB+SB, while needing only 10-20 cores. A four-core extended TB may suffice for large, highly suspicious anterior lesions in small or slightly enlarged prostates.

Multicentre evaluation of magnetic resonance imaging supported transperineal prostate biopsy in biopsy-naïve men with suspicion of prostate cancer.

OBJECTIVES: To analyse the detection rates of primary magnetic resonance imaging (MRI)-fusion transperineal prostate biopsy using combined targeted and systematic core distribution in three tertiary referral centres. PATIENTS AND METHODS: In this multicentre, prospective outcome study, 807 consecutive biopsy-naïve patients underwent MRI-guided transperineal prostate biopsy, as the first diagnostic intervention, between 10/2012 and 05/2016. MRI was reported following the Prostate Imaging-Reporting and Data System (PI-RADS) criteria. In all, 236 patients had 18-24 systematic transperineal biopsies only, and 571 patients underwent additional targeted biopsies either by MRI-fusion or cognitive targeting if PI-RADS ≥3 lesions were present. Detection rates for any and Gleason score 7-10 cancer in targeted and overall biopsy were calculated and predictive values were calculated for different PI-RADS and PSA density (PSAD) groups. RESULTS: Cancer was detected in 68% of the patients (546/807) and Gleason score 7-10 cancer in 49% (392/807). The negative predictive value of 236 PI-RADS 1-2 MRI in combination with PSAD of <0.1 ng/mL/mL for Gleason score 7-10 was 0.91 (95% confidence interval ± 0.07, 8% of study population). In 418 patients with PI-RADS 4-5 lesions using targeted plus systematic biopsies, the cancer detection rate of Gleason score 7-10 was significantly higher at 71% vs 59% and 61% with either approach alone (P < 0.001). For 153 PI-RADS 3 lesions, the detection rate was 31% with no significant difference to systematic biopsies with 27% (P > 0.05). Limitations include variability of multiparametric MRI (mpMRI) reading and Gleason grading. CONCLUSION: MRI-based transperineal biopsy performed at high-volume tertiary care centres with a significant experience of prostate mpMRI and image-guided targeted biopsies yielded high detection rates of Gleason score 7-10 cancer. Prostate biopsies may not be needed for men with low PSAD and an unsuspicious MRI. In patients with high probability lesions, combined targeted and systematic biopsies are recommended.

Evaluating the effect of rectal distension on prostate multiparametric MRI image quality.

PURPOSE: To evaluate the effect of rectal distension on the quality of anatomical and functional prostate multiparametric (mp) MRI. MATERIALS AND METHODS: Multiparametric (mp) 3T-MRI images of 173 patients were independently evaluated by two radiologists in this retrospective study. Planimetry rectal volumes were derived and a subjective assessment of rectal distension was made using a 5-point Likert scale (1=no stool/gas, 5=large amount of stool/gas). Image quality of diffusion-weighted imaging (DWI) was evaluated using a 5-point Likert scale. DWI was further scored for distortion and artefact. T2W images were evaluated for image sharpness and the presence of motion artefact. The stability of the dynamic contrast-enhancement acquisition was assessed by recording the number of corrupt data points during the wash-out phase. RESULTS: There was a strong correlation between subjective scoring of rectal loading and objectively measured rectal volume (r=0.82), p<0.001. A significant correlation was shown between increased rectal distension and both reduced DW image quality (r=-0.628, p<0.001), and increased DW image distortion (r=0.814, p<0.001). There was also a significant trend for rectal distension to increase artefact at DWI (r=0.154, p=0.042). Increased rectal distension led to increased motion artefact on T2 (p=0.0096), but did not have a significant effect on T2-sharpness (p=0.0638). There was no relationship between rectal distension and DCE image quality (p=0.693). 63 patients underwent lesion-targeted biopsy post MRI, there was a trend to higher positive predictive values in patients with minor rectal distension (34/38, 89.5%) compared to those with moderate/marked distension (18/25, 72%), p=0.09. CONCLUSION: Rectal distension has a significant negative effect on the quality of both T2W and DW images. Consideration should therefore be given to bowel preparation prior to prostate mpMRI to optimise image quality.

The influence of prostate-specific antigen density on positive and negative predictive values of multiparametric magnetic resonance imaging to detect Gleason score 7-10 prostate cancer in a repeat biopsy setting.

OBJECTIVES: To evaluate the influence of prostate-specific antigen density (PSAD) on positive (PPV) and negative (NPV) predictive values of multiparametric magnetic resonance imaging (mpMRI) to detect Gleason score ≥7 cancer in a repeat biopsy setting. PATIENTS AND METHODS: Retrospective study of 514 men with previous prostate biopsy showing no or Gleason score 6 cancer. All had mpMRI, graded 1-5 on a Likert scale for cancer suspicion, and subsequent targeted and 24-core systematic image-fusion guided transperineal biopsy in 2013-2015. The NPVs and PPVs of mpMRIs for detecting Gleason score ≥7 cancer were calculated (±95% confidence intervals) for PSAD ≤0.1, 0.1-0.2, ≤0.2 and >0.2 ng/mL/mL, and compared by chi-square test for linear trend. RESULTS: Gleason score ≥7 cancer was detected in 31% of the men. The NPV of Likert 1-2 mpMRI was 0.91 (±0.04) with a PSAD of ≤0.2 ng/mL/mL and 0.71 (±0.16) with a PSAD of >0.2 ng/mL/mL (P = 0.003). For Likert 3 mpMRI, PPV was 0.09 (±0.06) with a PSAD of ≤0.2 ng/mL/mL and 0.44 (±0.19) with a PSAD of >0.2 ng/mL/mL (P = 0.002). PSAD also significantly affected the PPV of Likert 4-5 mpMRI lesions: the PPV was 0.47 (±0.08) with a PSAD of ≤0.2 ng/mL/mL and 0.66 (±0.10) with a PSAD of >0.2 ng/mL/mL (P < 0.001). CONCLUSION: In a repeat biopsy setting, a PSAD of ≤0.2 ng/mL/mL is associated with low detection of Gleason score ≥7 prostate cancer, not only in men with negative mpMRI, but also in men with equivocal imaging. Surveillance, rather than repeat biopsy, may be appropriate for these men. Conversely, biopsies are indicated in men with a high PSAD, even if an mpMRI shows no suspicious lesion, and in men with an mpMRI suspicious for cancer, even if the PSAD is low.

Multicentre evaluation of targeted and systematic biopsies using magnetic resonance and ultrasound image-fusion guided transperineal prostate biopsy in patients with a previous negative biopsy.

OBJECTIVES: To evaluate the detection rates of targeted and systematic biopsies in magnetic resonance imaging (MRI) and ultrasound (US) image-fusion transperineal prostate biopsy for patients with previous benign transrectal biopsies in two high-volume centres. PATIENTS AND METHODS: A two centre prospective outcome study of 487 patients with previous benign biopsies that underwent transperineal MRI/US fusion-guided targeted and systematic saturation biopsy from 2012 to 2015. Multiparametric MRI (mpMRI) was reported according to Prostate Imaging Reporting and Data System (PI-RADS) Version 1. Detection of Gleason score 7-10 prostate cancer on biopsy was the primary outcome. Positive (PPV) and negative (NPV) predictive values including 95% confidence intervals (95% CIs) were calculated. Detection rates of targeted and systematic biopsies were compared using McNemar's test. RESULTS: The median (interquartile range) PSA level was 9.0 (6.7-13.4) ng/mL. PI-RADS 3-5 mpMRI lesions were reported in 343 (70%) patients and Gleason score 7-10 prostate cancer was detected in 149 (31%). The PPV (95% CI) for detecting Gleason score 7-10 prostate cancer was 0.20 (±0.07) for PI-RADS 3, 0.32 (±0.09) for PI-RADS 4, and 0.70 (±0.08) for PI-RADS 5. The NPV (95% CI) of PI-RADS 1-2 was 0.92 (±0.04) for Gleason score 7-10 and 0.99 (±0.02) for Gleason score ≥4 + 3 cancer. Systematic biopsies alone found 125/138 (91%) Gleason score 7-10 cancers. In patients with suspicious lesions (PI-RADS 4-5) on mpMRI, systematic biopsies would not have detected 12/113 significant prostate cancers (11%), while targeted biopsies alone would have failed to diagnose 10/113 (9%). In equivocal lesions (PI-RADS 3), targeted biopsy alone would not have diagnosed 14/25 (56%) of Gleason score 7-10 cancers, whereas systematic biopsies alone would have missed 1/25 (4%). Combination with PSA density improved the area under the curve of PI-RADS from 0.822 to 0.846. CONCLUSION: In patients with high probability mpMRI lesions, the highest detection rates of Gleason score 7-10 cancer still required combined targeted and systematic MRI/US image-fusion; however, systematic biopsy alone may be sufficient in patients with equivocal lesions. Repeated prostate biopsies may not be needed at all for patients with a low PSA density and a negative mpMRI read by experienced radiologists.

Comparison of initial and tertiary centre second opinion reads of multiparametric magnetic resonance imaging of the prostate prior to repeat biopsy.

OBJECTIVES: To investigate the value of second-opinion evaluation of multiparametric prostate magnetic resonance imaging (MRI) by subspecialised uroradiologists at a tertiary centre for the detection of significant cancer in transperineal fusion prostate biopsy. METHODS: Evaluation of prospectively acquired initial and second-opinion radiology reports of 158 patients who underwent MRI at regional hospitals prior to transperineal MR/untrasound fusion biopsy at a tertiary referral centre over a 3-year period. Gleason score (GS) 7-10 cancer, positive predictive value (PPV) and negative (NPV) predictive value (±95 % confidence intervals) were calculated and compared by Fisher's exact test. RESULTS: Disagreement between initial and tertiary centre second-opinion reports was observed in 54 % of cases (86/158). MRIs had a higher NPV for GS 7-10 in tertiary centre reads compared to initial reports (0.89 ± 0.08 vs 0.72 ± 0.16; p = 0.04), and a higher PPV in the target area for all cancer (0.61 ± 0.12 vs 0.28 ± 0.10; p = 0.01) and GS 7-10 cancer (0.43 ± 0.12 vs 0.2 3 ± 0.09; p = 0.02). For equivocal suspicion, the PPV for GS 7-10 was 0.12 ± 0.11 for tertiary centre and 0.11 ± 0.09 for initial reads; p = 1.00. CONCLUSIONS: Second readings of prostate MRI by subspecialised uroradiologists at a tertiary centre significantly improved both NPV and PPV. Reporter experience may help to reduce overcalling and avoid overtargeting of lesions. KEY POINTS: • Multiparametric MRIs were more often called negative in subspecialist reads (41 % vs 20 %). • Second readings of prostate mpMRIs by subspecialist uroradiologists significantly improved NPV and PPV. • Reporter experience may reduce overcalling and avoid overtargeting of lesions. • Greater education and training of radiologists in prostate MRI interpretation is advised.

Correction: Positive Contrast MRI Techniques for Visualization of Iron-Loaded Hernia Mesh Implants in Patients.

[This corrects the article DOI: 10.1371/journal.pone.0155717.].

Positive Contrast MRI Techniques for Visualization of Iron-Loaded Hernia Mesh Implants in Patients.

OBJECT: In MRI, implants and devices can be delineated via susceptibility artefacts. To discriminate susceptibility voids from proton-free structures, different positive contrast techniques were implemented. The purpose of this study was to evaluate a pulse sequence-based positive contrast technique (PCSI) and a post-processing susceptibility gradient mapping algorithm (SGM) for visualization of iron loaded mesh implants in patients. MATERIAL AND METHODS: Five patients with iron-loaded MR-visible inguinal hernia mesh implants were examined at 1.5 Tesla. A gradient echo sequence (GRE; parameters: TR: 8.3ms; TE: 4.3ms; NSA:2; FA:20°; FOV:350mm²) and a PCSI sequence (parameters: TR: 25ms; TE: 4.6ms; NSA:4; FA:20°; FOV:350mm²) with on-resonant proton suppression were performed. SGM maps were calculated using two algorithms. Image quality and mesh delineation were independently evaluated by three radiologists. RESULTS: On GRE, the iron-loaded meshes generated distinct susceptibility-induced signal voids. PCSI exhibited susceptibility differences including the meshes as hyperintense signals. SGM exhibited susceptibility differences with positive contrast. Visually, the different algorithms presented no significant differences. Overall, the diagnostic value was rated best in GRE whereas PCSI and SGM were barely "sufficient". CONCLUSION: Both "positive contrast" techniques depicted implanted meshes with hyperintense signal. SGM comes without additional acquisition time and can therefore be utilized in every patient.

Multiparametric Prostate Magnetic Resonance Imaging and Cognitively Targeted Transperineal Biopsy in Patients With Previous Abdominoperineal Resection and Suspicion of Prostate Cancer.

OBJECTIVE: To report our experience with a combination of prostate magnetic resonance imaging (MRI) and transperineal ultrasound biopsy for evaluating the prostate in patients with elevated prostate-specific antigen (PSA) who have previously undergone abdominoperineal resection (APR). PATIENTS AND METHODS: We reviewed the records of 11 patients with a history of APR and clinical suspicion of prostate cancer due to elevated PSA levels over a 5-year period. All patients underwent multiparametric MRI at our institution prior to biopsy. MR diagnoses were validated either by transperineal ultrasound biopsy (Likert 3-5) guided by visual registration or clinical follow-up >6 months (Likert 1-2). RESULTS: All 7 cases with highly suspicious lesions (Likert 4-5) on MRI demonstrated cancer-1 case of Gleason 3 + 3 and 6 cases of Gleason ≥3 + 4 disease. Two cases with Likert 3 MR lesions revealed benign tissue upon biopsy. Two patients with no suspicious lesions on MRI were followed-up clinically, with PSA levels remaining stable over a mean period of 17.5 months (range 7-28 months). CONCLUSION: The use of prebiopsy multiparametric prostate MRI and subsequent cognitively targeted transperineal biopsy guided by visual registration can aid in the diagnostic pathway of patients with APR and a suspicion of prostate cancer.

Diagnostic accuracy of diffusion-weighted magnetic resonance imaging versus positron emission tomography/computed tomography for early response assessment of liver metastases to Y90-radioembolization.

OBJECTIVES: Patients with hepatic metastases who are candidates for Y90-radioembolization (Y90-RE) usually have advanced tumor stages with involvement of both liver lobes. Per current guidelines, these patients have usually undergone several cycles of potentially hepatotoxic systemic chemotherapy before Y90-RE is at all considered, requiring split (lobar) treatment sessions to reduce hepatic toxicity. Assessing response to Y90-RE early, that is, already after the first lobar session, would be helpful to avoid an ineffective and potentially hepatotoxic second lobar treatment. We investigated the accuracy with which diffusion- weighted magnetic resonance imaging (DWI-MRI) and positron emission tomography/computed tomography (PET/CT) can provide this information. METHODS: An institutional review board-approved prospective intraindividual comparison trial on 35 patients who underwent fluorodeoxyglucose PET/CT and DWI-MRI within 6 weeks before and 6 weeks after Y90-RE to treat secondary-progressive liver metastases from solid cancers (20 colorectal, 13 breast, 2 other) was performed. An increase of minimal apparent diffusion coefficient (ADCmin) or decrease of maximum standard uptake value (SUVmax) by at least 30% was regarded as positive response. Long-term clinical and imaging follow-up was used to distinguish true- from false-response classifications. RESULTS: On the basis of long-term follow-up, 23 (66%) of 35 patients responded to the Y90 treatment. No significant changes of metastases size or contrast enhancement were observable on pretreatment versus posttreatment CT or magnetic resonance images.However, overall SUVmax decreased from 8.0 ± 3.9 to 5.5 ± 2.2 (P < 0.0001), and ADCmin increased from 0.53 ± 0.13 × 10(-3) mm2/s to 0.77 ± 0.26 × 10(-3) mm2/s (P < 0.0001). Pretherapeutic versus posttherapeutic changes of ADCmin and SUVmax correlated moderately (r = -0.53). In 4 of the 35 patients (11%), metastases were fluorodeoxyglucose-negative such that no response assessment was possible by PET. In 25 (71%) of the 35 patients, response classification by PET and DWI-MRI was concordant; in 6 (17%) of the 35, it was discordant. In 5 of the 6 patients with discordant classifications, follow-up confirmed diagnoses made by DWI. The positive predictive value to predict response was 22 (96%) of 23 for MRI and 15 (88%) of 17 for PET. The negative predictive value to predict absence was 11 (92%) of 12 for MRI and 10 (56%) of 18 for PET. Sensitivity for detecting response was significantly higher for MRI (96%; 22/23) than for PET (65%; 15/23) (P < 0.02). CONCLUSIONS: Diffusion-weighted magnetic resonance imaging appears superior to PET/CT for early response assessment in patients with hepatic metastases of common solid tumors. It may be used in between lobar treatment sessions to guide further management of patients who undergo Y90-RE for hepatic metastases.

Assessment of BI-RADS category 4 lesions detected with screening mammography and screening US: utility of MR imaging.

PURPOSE: To investigate the utility of magnetic resonance (MR) imaging according to different types of Breast Imaging Reporting and Data System (BI-RADS) category 4 findings from screening mammography and/or screening ultrasonography (US). MATERIALS AND METHODS: This institutional review board-approved prospective study included 340 patients in whom 353 lesions were detected at screening mammography or US and were rated BI-RADS category 4 after appropriate conventional work-up. Written informed consent was obtained from all patients. Women underwent standard dynamic contrast material-enhanced MR imaging for further assessment. Women with negative or benign MR findings who did not proceed to biopsy underwent intensified follow-up for at least 18 months. Pure clustered microcalcifications were followed up for at least 24 months. RESULTS: Of the 353 study findings, 66 (18.7%) were finally shown to be true-positive (23 cases of ductal carcinoma in situ [DCIS], 43 invasive cancers) and 287 (81.3%) were false-positive. Assessment of MR imaging findings led to a correct diagnosis of no breast cancer in 264 of the 287 false-positive findings (92%) and helped confirm the presence of breast cancer in 63 of 66 malignancies. The false-negative rate for pure clustered microcalcifications was 12% (three of 25 cases) because of three nonenhancing low-grade DCIS cases; in turn, MR imaging depicted additional invasive cancers in three women with false-positive findings from mammography and US. For mammographic findings other than pure clustered microcalcifications, MR imaging increased the positive predictive value (PPV) from 17.5% (21 of 120 cases; 95% confidence interval [CI]: 10.7%, 24.3%) to 78% (21 of 27 cases; 95% CI: 62.1%, 93.5%), with a false-negative rate of 0%. For all US findings, MR imaging increased the PPV from 12.9% (20 of 155 cases; 95% CI: 7.6%, 18.2%) to 69% (20 of 29 cases; 95% CI: 52.2%, 85.8%), again with a false-negative rate of 0%. MR imaging resulted in false-positive findings that led to MR imaging-guided biopsy in five of the 340 patients (1.5%). CONCLUSION: MR imaging is useful for the noninvasive work-up of lesions classified as BI-RADS category 4 at mammography or US and can help avoid 92% of unnecessary biopsies. The false-negative rate was 0% for all US findings and for all mammographic findings except pure clustered microcalcifications. Additional invasive cancers were identified in three women with false-positive findings from mammography and US.

Does MRI breast "density" (degree of background enhancement) correlate with mammographic breast density?

PURPOSE: To investigate whether mammographic breast densities and the respective degree of MRI background enhancement would correlate. Mammographic breast density is coded to communicate how likely a cancer is obscured by parenchyma. Similarly, background enhancement in breast MRI could obscure enhancing cancer tissue. MATERIALS AND METHODS: A total of 468 women underwent standard full-field digital mammography and dynamic contrast-enhanced breast MRI in our institution. Mammographic breast density was scored according to the American College of Radiology-classification; background enhancement in MRI was scored on a 4-point scale from absent to severe. Breast "density classes" were retrospectively compared by analyzing the differences between scores for mammography and MRI. Statistical correlation was calculated using the Spearman coefficient. RESULTS: Scores matched in 19% of women (90/468) but differed in 81% (378/468). A deviation by 1 point was observed in 33% (157/468), by 2 points in 38% (179/468), by 3 in 9% (42/468). Scores for background enhancement were lower than mammographic scores in 371/468 (79.3%), equivalent in 90/468 (19.2%), and higher in 7/468 (1.5%). CONCLUSION: Mammographic breast density does not correlate with the degree of background enhancement in MRI. In the majority of women, scores for background enhancement in MRI will be lower than the respective mammographic density scores.