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Purpose To compare diffusion-weighted imaging (DWI) with thermal dosimetry as a noncontrast method to predict ablation margins in individuals with prostate cancer treated with MRI-guided focused ultrasound (MRgFUS) ablation. Materials and Methods This secondary analysis of a prospective trial (ClinicalTrials.gov no. NCT01657942) included 17 participants (mean age, 64 years ± 6 [SD]; all male) who were treated for prostate cancer using MRgFUS in whom DWI was performed immediately after treatment. Ablation contours from computed thermal dosimetry and DWI as drawn by two blinded radiologists were compared against the reference standard of ablation assessment, posttreatment contrast-enhanced nonperfused volume (NPV) contours. The ability of each method to predict the ablation zone was analyzed quantitively using Dice similarity coefficients (DSCs) and mean Hausdorff distances (mHDs). Results DWI revealed a hyperintense rim at the margin of the ablation zone. While DWI accurately helped predict treatment margins, thermal dose contours underestimated the extent of the ablation zone compared with the T1-weighted NPV imaging reference standard. Quantitatively, contour assessment between methods showed that DWI-drawn contours matched postcontrast NPV contours (mean DSC = 0.84 ± 0.05 for DWI, mHD = 0.27 mm ± 0.13) better than the thermal dose contours did (mean DSC = 0.64 ± 0.12, mHD = 1.53 mm ± 1.20) (P < .001). Conclusion This study demonstrates that DWI, which can visualize the ablation zone directly, is a promising noncontrast method that is robust to treatment-related bulk motion compared with thermal dosimetry and correlates better than thermal dosimetry with the reference standard T1-weighted NPV. Keywords: Interventional-Body, Ultrasound-High-Intensity Focused (HIFU), Genital/Reproductive, Prostate, Oncology, Imaging Sequences, MRI-guided Focused Ultrasound, MR Thermometry, Diffusionweighted Imaging, Prostate Cancer ClinicalTrials.gov Identifier no. NCT01657942 Supplemental material is available for this article. © RSNA, 2024.

BACKGROUND:  The magnetic resonance imaging-guided focused ultrasound (MRgFUS) has emerged as an innovative treatment for patients with medically refractory essential tremor (ET).
OBJECTIVE:  This retrospective observational study aims to present the results of the first five patients with medically refractory ET who underwent MRgFUS treatment at this pioneering medical unit in Portugal.
METHODS:  We conducted a retrospective chart review for the first five patients who underwent unilateral MRgFUS thalamotomy of the ventral intermediate (Vim) nucleus to treat medically refractory ET at our medical unit.
RESULTS:  The mean patient age was 65.4 (26-84) years, and 60% were male. All patients had a family history of ET. The mean duration of disease was 17.4 years (range 10-24 years), and their dominant hand was the right. According to personal preference, the thalamotomy was performed on the left side in four patients, and on the right side in one. The MRgFUS thalamotomy led to significant improvements in both the clinical rating scale for tremor (CRST) score, by 62%, and the CRST composite score for the treated hand, by 73%. All patients experienced improvements in functionality and quality of life, by 52%. No severe adverse events were observed, and those that did occur during and following the procedure were mild and transient.
CONCLUSIONS:  The initial results from Portugal\'s first MRgFUS medical unit indicate promising outcomes, with improvement in quality of life, as well as mild and temporary adverse events These findings contribute to the growing body of literature supporting the efficacy and safety of MRgFUS as a viable treatment option for patients with medication-resistant ET.
BACKGROUND:  A talomotomia por ultrassons focados - guiada por imagem de ressonância magnética (MRgFUS) surgiu recentemente como um tratamento inovador para pacientes com tremor essencial (TE) refratário ao tratamento médico.
OBJECTIVE:  Este estudo observacional retrospectivo tem como objetivo apresentar os resultados dos primeiros cinco pacientes com TE refratário à medicação submetidos ao tratamento com MRgFUS numa unidade médica pioneira em Portugal. MéTODOS:  Realizamos uma revisão retrospectiva dos dados clínicos dos cinco primeiros pacientes submetidos a talamotomia MRgFUS unilateral do núcleo ventral intermédio (Vim) para tratamento do TE medicamente refratário em nossa unidade médica.
RESULTS:  A idade média dos pacientes era de 65,4 (26–84) anos, e 60% eram do sexo masculino. Todos os pacientes tinham história familiar de TE. A duração média da doença foi de 17,4 anos, e todos eram destros. De acordo com a preferência individual, em 4 pacientes, a talamotomia foi realizada no lado esquerdo, e em um, no lado direito. A talamotomia por MRgFUS levou a melhorias significativas tanto na pontuação da escala de classificação clínica para tremor (CRST), de 62%, e na pontuação composta da CRST para a mão tratada, de 73%. Todos os pacientes apresentaram melhorias na funcionalidade e na qualidade de vida, de 52%. Não foram observados efeitos adversos graves e os que ocorreram durante e após o procedimento foram ligeiros e transitórios. CONCLUSãO:  Os resultados iniciais da primeira unidade médica MRgFUS de Portugal indicam melhorias na qualidade de vida dos pacientes, com efeitos adversos ligeiros e transitórios. Estes dados reforçam a evidência crescente sobre a eficácia e segurança da talamotomia por MRgFUS como opção viável para pacientes com TE resistente à medicação.

OBJECTIVE: To investigate whether MRI-guided transrectal laser ablation is safe and effective for the treatment of lower urinary tract symptoms caused by BPH.
METHODS: This single-center retrospective cohort study evaluated men who underwent MRI-guided transrectal laser ablation for BPH between February 2017 and July 2021. Age, prostate-specific antigen, prostate volume, prior surgical BPH treatments if any, International Prostate Symptom Score (IPSS) and Sexual Health Inventory of Men (SHIM) were collected. The primary outcome measures assessed were change in IPSS and SHIM 6, 12 and 24 months after laser ablation and adverse events.
RESULTS: Fifty-two patients were included, having completed at least one follow-up survey. The mean patient age was 62.9 ± 5.7 years, and mean prostate volume was 80.2 ± 39.2 cc. Eighteen patients (34.6%) had received a prior BPH treatment. The IPSS scores dropped an average of 16.7 ± 7.0 (p < 0.001), 16.9 ± 7.5 (p < 0.001) and 17.1 ± 7.2 (p < 0.001) points from baseline at 6, 12 and 24 months, respectively. There was no statistically significant difference in IPSS score drop between patients who had received a prior BPH procedure and those who had not (p = 0.628). The SHIM scores showed a statistically insignificant increase at all time points. Nineteen patients (36.5%) reported a complication. There were 12 grade II complications (23%) and seven grade I complications (13.5%). There were no grade III or higher complications.
CONCLUSIONS: Transrectal MRI-guided focal laser ablation is safe and effective for the treatment of lower urinary tract symptoms caused by BPH, with a significant improvement in symptom severity after 2 years.

OBJECTIVE: To compare transperineal (TP) vs transrectal (TR) magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS) fusion-guided prostate biopsy (PBx) in a large, ethnically diverse and multiracial cohort.
METHODS: Consecutive patients who underwent multiparametric (mp) MRI followed by TP or TR TRUS-fusion guided PBx, were identified from a prospective database (IRB #HS-13-00663). All patients underwent mpMRI followed by 12-14 core systematic PBx. A minimum of two additional target-biopsy cores were taken per PIRADS≥3 lesion. The endpoint was the detection of clinically significant prostate cancer (CSPCa; Grade Group, GG≥2). Statistical significance was defined as p<0.05.
RESULTS: A total of 1491 patients met inclusion criteria, with 480 undergoing TP and 1011 TR PBx. Overall, 11% of patients were Asians, 5% African Americans, 14% Hispanic, 14% Others, and 56% White, similar between TP and TR (p=0.4). For PIRADS 3-5, the TP PBx CSPCa detection was significantly higher (61% vs 54%, p=0.03) than TR PBx, but not for PIRADS 1-2 (13% vs 13%, p=1.0). After adjusting for confounders on multivariable analysis, Black race, but not the PBx approach (TP vs TR), was an independent predictor of CSPCa detection. The median maximum cancer core length (11 vs 8mm; p<0.001) and percent (80% vs 60%; p<0.001) were greater for TP PBx even after adjusting for confounders.
CONCLUSIONS: In a large and diverse cohort, Black race, but not the biopsy approach, was an independent predictor for CSPCa detection. TP and TR PBx yielded similar CSPCa detection rates; however the TP PBx was histologically more informative.

OBJECTIVE: Cardiovascular magnetic resonance (CMR) imaging excels in providing detailed three-dimensional anatomical information together with excellent soft tissue contrast and has already become a valuable tool for diagnostic evaluation, electrophysiological procedure (EP) planning, and therapeutical stratification of atrial or ventricular rhythm disorders. CMR-based identification of ablation targets may significantly impact existing concepts of interventional electrophysiology. In order to exploit the inherent advantages of CMR imaging to the fullest, CMR-guided ablation procedures (EP-CMR) are justly considered the ultimate goal.
RESULTS: Electrophysiological cardiovascular magnetic resonance (EP-CMR) interventional procedures have more recently been introduced to the CMR armamentarium: in a single-center series of 30 patients, an EP-CMR guided ablation success of 93% has been reported, which is comparable to conventional ablation outcomes for typical atrial flutter and procedure and ablation time were also reported to be comparable. However, moving on from already established workflows for the ablation of typical atrial flutter in the interventional CMR environment to treatment of more complex ventricular arrhythmias calls for technical advances regarding development of catheters, sheaths and CMR-compatible defibrillator equipment. CMR imaging has already become an important diagnostic tool in the standard clinical assessment of cardiac arrhythmias. Previous studies have demonstrated the feasibility and safety of performing electrophysiological interventional procedures within the CMR environment and fully CMR-guided ablation of typical atrial flutter can be implemented as a routine procedure in experienced centers. Building upon established workflows, the market release of new, CMR-compatible interventional devices may finally enable targeting ventricular arrhythmias.

BACKGROUND: The non-perfused volume divided by total fibroid load (NPV/TFL) is a predictive outcome parameter for MRI-guided high-intensity focused ultrasound (MR-HIFU) treatments of uterine fibroids, which is related to long-term symptom relief. In current clinical practice, the MR-HIFU outcome parameters are typically determined by visual inspection, so an automated computer-aided method could facilitate objective outcome quantification. The objective of this study was to develop and evaluate a deep learning-based segmentation algorithm for volume measurements of the uterus, uterine fibroids, and NPVs in MRI in order to automatically quantify the NPV/TFL.
METHODS: A segmentation pipeline was developed and evaluated using expert manual segmentations of MRI scans of 115 uterine fibroid patients, screened for and/or undergoing MR-HIFU treatment. The pipeline contained three separate neural networks, one per target structure. The first step in the pipeline was uterus segmentation from contrast-enhanced (CE)-T1w scans. This segmentation was subsequently used to remove non-uterus background tissue for NPV and fibroid segmentation. In the following step, NPVs were segmented from uterus-only CE-T1w scans. Finally, fibroids were segmented from uterus-only T2w scans. The segmentations were used to calculate the volume for each structure. Reliability and agreement between manual and automatic segmentations, volumes, and NPV/TFLs were assessed.
RESULTS: For treatment scans, the Dice similarity coefficients (DSC) between the manually and automatically obtained segmentations were 0.90 (uterus), 0.84 (NPV) and 0.74 (fibroid). Intraclass correlation coefficients (ICC) were 1.00 [0.99, 1.00] (uterus), 0.99 [0.98, 1.00] (NPV) and 0.98 [0.95, 0.99] (fibroid) between manually and automatically derived volumes. For manually and automatically derived NPV/TFLs, the mean difference was 5% [-41%, 51%] (ICC: 0.66 [0.32, 0.85]).
CONCLUSIONS: The algorithm presented in this study automatically calculates uterus volume, fibroid load, and NPVs, which could lead to more objective outcome quantification after MR-HIFU treatments of uterine fibroids in comparison to visual inspection. When robustness has been ascertained in a future study, this tool may eventually be employed in clinical practice to automatically measure the NPV/TFL after MR-HIFU procedures of uterine fibroids.

BACKGROUND: Numerous studies have shown that magnetic resonance imaging (MRI)-targeted biopsy approaches are superior to traditional systematic transrectal ultrasound guided biopsy (TRUS-Bx). The optimal number of biopsy cores to be obtained per lesion identified on multiparametric MRI (mpMRI) images, however, remains a matter of debate. The aim of this study was to evaluate the incremental value of additional biopsy cores in an MRI-targeted \"in-bore\"-biopsy (MRI-Bx) setting.
METHODS: Two hundred and forty-five patients, who underwent MRI-Bx between June 2014 and September 2021, were included in this retrospective single-center analysis. All lesions were biopsied with at least five biopsy cores and cumulative detection rates for any cancer (PCa) as well as detection rates of clinically significant cancers (csPCa) were calculated for each sequentially labeled biopsy core. The cumulative per-core detection rates are presented as whole numbers and as proportion of the maximum detection rate reached, when all biopsy cores were considered. CsPCa was defined as Gleason Score (GS) ≥ 7 (3 + 4).
RESULTS: One hundred and thirty-two of 245 Patients (53.9%) were diagnosed with prostate cancer and csPCa was found in 64 (26.1%) patients. The first biopsy core revealed csPCa/ PCa in 76.6% (49/64)/ 81.8% (108/132) of cases. The second, third and fourth core found csPCa/ PCa not detected by previous cores in 10.9% (7/64)/ 8.3% (11/132), 7.8% (5/64)/ 5.3% (7/132) and 3.1% (2/64)/ 3% (4/132) of cases, respectively. Obtaining one or more cores beyond the fourth biopsy core resulted in an increase in detection rate of 1.6% (1/64)/ 1.5% (2/132).
CONCLUSIONS: We found that obtaining five cores per lesion maximized detection rates. If, however, future research should establish a clear link between the incidence of serious complications and the number of biopsy cores obtained, a three-core biopsy might suffice as our results suggest that about 95% of all csPCa are detected by the first three cores.

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Background Biparametric MRI (bpMRI) of the prostate is an alternative to multiparametric MRI (mpMRI), with lower cost and increased accessibility. Studies investigating the positive predictive value (PPV) of bpMRI-directed compared with mpMRI-directed targeted biopsy are lacking in the literature. Purpose To compare the PPVs of bpMRI-directed and mpMRI-directed targeted prostate biopsies. Materials and Methods This retrospective cross-sectional study evaluated men who underwent bpMRI-directed or mpMRI-directed transrectal US (TRUS)-guided targeted prostate biopsy at a single institution from January 2015 to December 2022. The PPVs for any prostate cancer (PCa) and clinically significant PCa (International Society of Urological Pathology grade ≥2) were calculated for bpMRI and mpMRI using mixed-effects logistic regression modeling. Results A total of 1538 patients (mean age, 67 years ± 8 [SD]) with 1860 lesions underwent bpMRI-directed (55%, 849 of 1538) or mpMRI-directed (45%, 689 of 1538) prostate biopsy. When adjusted for the number of lesions and Prostate Imaging Reporting and Data System (PI-RADS) score, there was no difference in PPVs for any PCa or clinically significant PCa (P = .61 and .97, respectively) with bpMRI-directed (55% [95% CI: 51, 59] and 34% [95% CI: 30, 38], respectively) or mpMRI-directed (56% [95% CI: 52, 61] and 34% [95% CI: 30, 39], respectively) TRUS-guided targeted biopsy. PPVs for any PCa and clinically significant PCa stratified according to clinical indication were as follows: biopsy-naive men, 64% (95% CI: 59, 69) and 43% (95% CI: 39, 48) for bpMRI, 67% (95% CI: 59, 75) and 51% (95% CI: 43, 59) for mpMRI (P = .65 and .26, respectively); and active surveillance, 59% (95% CI: 49, 69) and 30% (95% CI: 22, 39) for bpMRI, 73% (95% CI: 65, 89) and 38% (95% CI: 31, 47) for mpMRI (P = .04 and .23, respectively). Conclusion There was no evidence of a difference in PPV for clinically significant PCa between bpMRI- and mpMRI-directed TRUS-guided targeted biopsy. © RSNA, 2024 Supplemental material is available for this article.