Publications by authors named "Harri Merisaari"

47 Publications

Comparative analysis of 1152 African-American and European-American men with prostate cancer identifies distinct genomic and immunological differences.

Commun Biol 2021 Jun 3;4(1):670. Epub 2021 Jun 3.

Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA.

Racial disparities in prostate cancer have not been well characterized on a genomic level. Here we show the results of a multi-institutional retrospective analysis of 1,152 patients (596 African-American men (AAM) and 556 European-American men (EAM)) who underwent radical prostatectomy. Comparative analyses between the race groups were conducted at the clinical, genomic, pathway, molecular subtype, and prognostic levels. The EAM group had increased ERG (P < 0.001) and ETS (P = 0.02) expression, decreased SPINK1 expression (P < 0.001), and basal-like (P < 0.001) molecular subtypes. After adjusting for confounders, the AAM group was associated with higher expression of CRYBB2, GSTM3, and inflammation genes (IL33, IFNG, CCL4, CD3, ICOSLG), and lower expression of mismatch repair genes (MSH2, MSH6) (p < 0.001 for all). At the pathway level, the AAM group had higher expression of genes sets related to the immune response, apoptosis, hypoxia, and reactive oxygen species. EAM group was associated with higher levels of fatty acid metabolism, DNA repair, and WNT/beta-catenin signaling. Based on cell lines data, AAM were predicted to have higher potential response to DNA damage. In conclusion, biological characteristics of prostate tumor were substantially different in AAM when compared to EAM.
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http://dx.doi.org/10.1038/s42003-021-02140-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8175556PMC
June 2021

Computer extracted gland features from H&E predicts prostate cancer recurrence comparably to a genomic companion diagnostic test: a large multi-site study.

NPJ Precis Oncol 2021 May 3;5(1):35. Epub 2021 May 3.

Department of Urology, Case Western Reserve University, Cleveland, OH, USA.

Existing tools for post-radical prostatectomy (RP) prostate cancer biochemical recurrence (BCR) prognosis rely on human pathologist-derived parameters such as tumor grade, with the resulting inter-reviewer variability. Genomic companion diagnostic tests such as Decipher tend to be tissue destructive, expensive, and not routinely available in most centers. We present a tissue non-destructive method for automated BCR prognosis, termed "Histotyping", that employs computational image analysis of morphologic patterns of prostate tissue from a single, routinely acquired hematoxylin and eosin slide. Patients from two institutions (n = 214) were used to train Histotyping for identifying high-risk patients based on six features of glandular morphology extracted from RP specimens. Histotyping was validated for post-RP BCR prognosis on a separate set of n = 675 patients from five institutions and compared against Decipher on n = 167 patients. Histotyping was prognostic of BCR in the validation set (p < 0.001, univariable hazard ratio [HR] = 2.83, 95% confidence interval [CI]: 2.03-3.93, concordance index [c-index] = 0.68, median years-to-BCR: 1.7). Histotyping was also prognostic in clinically stratified subsets, such as patients with Gleason grade group 3 (HR = 4.09) and negative surgical margins (HR = 3.26). Histotyping was prognostic independent of grade group, margin status, pathological stage, and preoperative prostate-specific antigen (PSA) (multivariable p < 0.001, HR = 2.09, 95% CI: 1.40-3.10, n = 648). The combination of Histotyping, grade group, and preoperative PSA outperformed Decipher (c-index = 0.75 vs. 0.70, n = 167). These results suggest that a prognostic classifier for prostate cancer based on digital images could serve as an alternative or complement to molecular-based companion diagnostic tests.
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http://dx.doi.org/10.1038/s41698-021-00174-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8093226PMC
May 2021

Whole Brain Adiabatic T and Relaxation Along a Fictitious Field Imaging in Healthy Volunteers and Patients With Multiple Sclerosis: Initial Findings.

J Magn Reson Imaging 2021 Mar 6. Epub 2021 Mar 6.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

Background: In preclinical models of multiple sclerosis (MS), both adiabatic T (T ) and relaxation along a fictitious field (RAFF) imaging have demonstrated potential to noninvasively characterize MS.

Purpose: To evaluate the feasibility of whole brain T and RAFF imaging in healthy volunteers and patients with MS.

Study Type: Single institutional clinical trial.

Subjects: 38 healthy volunteers (24-69 years) and 21 patients (26-59 years) with MS. Five healthy volunteers underwent a second MR examination performed within 8 days. Clinical disease severity (The Expanded Disability Status Scale [EDSS] and The Multiple Sclerosis Severity Score [MSSS]) was evaluated at baseline and 1-year follow-up (FU).

Field Strength/sequence: RAFF in second rotating frame of reference (RAFF2) was performed at 3 T using 3D-fast-field echo with magnetization preparation, RF amplitude of 11.74 μT while the corresponding value for T was 13.50 μT. T -, T -, and FLAIR-weighted images were acquired with reconstruction voxel size 1.0 × 1.0 × 1.0 mm .

Assessment: The parametric maps of T and RAFF2 (T ) were calculated using a monoexponential model. Semi-automatic segmentation of MS lesions, white matter (WM), and gray matter (GM), and WM tracks was performed using T -, T -, and FLAIR-weighted images.

Statistical Tests: Regression analysis was used to evaluate correlation of T and T with age and disease severity while a Friedman test followed by Wilcoxon Signed Rank test for differences between tissue types. Short-term repeatability was evaluated on voxel level.

Results: Both T and T demonstrated good short-term repeatability with relative differences on voxel level in the range of 6.1%-11.9%. Differences in T and T between the tissue types in MS patients were significant (P < 0.05). T and T correlated (P < 0.001) with baseline EDSS/MSSM and disease progression at FU (P < 0.001).

Data Conclusion: Whole brain T and T at 3 T was feasible with significant differences in T and T values between tissues types and correlation with disease severity.

Evidence Level: 1 TECHNICAL EFFICACY: Stage 1.
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http://dx.doi.org/10.1002/jmri.27586DOI Listing
March 2021

Docetaxel chemotherapy response in PC3 prostate cancer mouse model detected by rotating frame relaxations and water diffusion.

NMR Biomed 2021 Apr 4;34(4):e4483. Epub 2021 Feb 4.

A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.

MRI is a common method of prostate cancer diagnosis. Several MRI-derived markers, including the apparent diffusion coefficient (ADC) based on diffusion-weighted imaging, have been shown to provide values for prostate cancer detection and characterization. The hypothesis of the study was that docetaxel chemotherapy response could be picked up earlier with rotating frame relaxation times T and T than with the continuous wave T , adiabatic T , adiabatic T , T , T or water ADC. Human PC3 prostate cancer cells expressing a red fluorescent protein were implanted in 21 male mice. Docetaxel chemotherapy was given once a week starting 1 week after cell implantation for 10 randomly selected mice, while the rest served as a control group (n = 11). The MRI consisted of relaxation along a fictitious field (RAFF) in the second (RAFF2) and fourth (RAFF4) rotating frames, T and T , continuous wave T , adiabatic T and adiabatic T relaxation time measurements and water ADC. MRI was conducted at 7 T, once a week up to 4 weeks from cell implantation. The tumor volume was monitored using T -weighted MRI and optical imaging. The histology was evaluated after the last imaging time point. Significantly reduced RAFFn, T T and conventional relaxation times 4 weeks after tumor implantation were observed in the treated tumors compared with the controls. The clearest short- and long-term responses were obtained with T , while no clear improvement in response to treatment was detected with novel methods compared with conventional methods or with RAFFn compared with all others. The tumor volume decreased after a two-week time point for the treated group and increased significantly in the control group, which was supported by increasing red fluorescent light emission in the control tumors. Decreased relaxation times were associated with successful chemotherapy outcomes. The results indicate altered relaxation mechanisms compared with higher dose chemotherapies previously published.
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http://dx.doi.org/10.1002/nbm.4483DOI Listing
April 2021

Association of Cumulative Paternal Early Life Stress With White Matter Maturation in Newborns.

JAMA Netw Open 2020 11 2;3(11):e2024832. Epub 2020 Nov 2.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Institute of Clinical Medicine, University of Turku, Turku, Finland.

Importance: Early life stress (ELS) has been shown to affect brain development and health outcomes. Recent animal studies have linked paternal early stress exposures with next-generation outcomes. Epigenetic inheritance through the male germline has been suggested to be one of the mechanisms.

Objectives: To test whether paternal ELS, as measured using the Trauma and Distress Scale, is associated with neonate brain development.

Design, Setting, And Participants: This cohort study included data from participants from the prospective 2-generation FinnBrain Birth Cohort, which was collected from 2011 to 2015. Pregnant women and the fathers were consecutively recruited at gestational week 12 from maternity clinics in Finland. Magnetic resonance imaging data were analyzed in 2019. Participants in this study were 72 families (infant, father, mother).

Exposure: Paternal exposure to ELS.

Main Outcomes And Measures: Fractional anisotropy (FA) values in the major white-matter tracts of the newborn brain.

Results: A total of 72 trios (infant, mother, and father) were analyzed. At the time of delivery, the mean (SD) age was 31.0 (4.4) years for fathers and 30.3 (4.5) years for mothers. Forty-one infants (57%) were boys; mean (SD) child age at inclusion was 26.9 (7.2) days from birth and 205 (8) days from estimated conception. Increasing levels of paternal ELS were associated with higher FA values in the newborn brain in the body of the corpus callosum, right superior corona radiata, and retrolenticular parts of the internal capsule. This association persisted after controlling for maternal ELS, maternal socioeconomic status (SES), maternal body mass index, maternal depressive symptoms during pregnancy, child sex, and child age from birth and gestation corrected age when imaged. In additional region-of-interest analyses, the association between FA values and paternal Trauma and Distress Scale sum scores remained statistically significant in the earliest maturing regions of the brain, eg, the genu of the corpus callosum (in the regression models, β = 0.00096; 95% CI, 0.00034-0.00158; P = .003) and the splenium (β = 0.00090; 95% CI, 0.00000-0.00180; P = .049).

Conclusions And Relevance: This cohort study found a statistically significant association between paternal ELS and offspring brain development. This finding may have far-reaching implications in pediatrics, as it suggests the possibility of a novel route of intergenerational inheritance of ELS on next-generation brain development.
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http://dx.doi.org/10.1001/jamanetworkopen.2020.24832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7686861PMC
November 2020

The impact of edema and fiber crossing on diffusion MRI metrics assessed in an ex vivo nerve phantom: Multi-tensor model vs. diffusion orientation distribution function.

NMR Biomed 2021 01 4;34(1):e4414. Epub 2020 Oct 4.

Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States.

Diffusion tensor imaging (DTI) has been employed for over 2 decades to noninvasively quantify central nervous system diseases/injuries. However, DTI is an inadequate simplification of diffusion modeling in the presence of coexisting inflammation, edema and crossing nerve fibers. We employed a tissue phantom using fixed mouse trigeminal nerves coated with various amounts of agarose gel to mimic crossing fibers in the presence of vasogenic edema. Diffusivity measures derived by DTI and diffusion basis spectrum imaging (DBSI) were compared at increasing levels of simulated edema and degrees of fiber crossing. Furthermore, we assessed the ability of DBSI, diffusion kurtosis imaging (DKI), generalized q-sampling imaging (GQI), q-ball imaging (QBI) and neurite orientation dispersion and density imaging to resolve fiber crossing, in reference to the gold standard angles measured from structural images. DTI-computed diffusivities and fractional anisotropy were significantly confounded by gel-mimicked edema and crossing fibers. Conversely, DBSI calculated accurate diffusivities of individual fibers regardless of the extent of simulated edema and degrees of fiber crossing angles. Additionally, DBSI accurately and consistently estimated crossing angles in various conditions of gel-mimicked edema when compared with the gold standard (r = 0.92, P = 1.9 × 10 , bias = 3.9°). Small crossing angles and edema significantly impact the diffusion orientation distribution function, making DKI, GQI and QBI less accurate in detecting and estimating fiber crossing angles. Lastly, we used diffusion tensor ellipsoids to demonstrate that DBSI resolves the confounds of edema and crossing fibers in the peritumoral edema region from a patient with lung cancer metastasis, while DTI failed. In summary, DBSI is able to separate two crossing fibers and accurately recover their diffusivities in a complex environment characterized by increasing crossing angles and amounts of gel-mimicked edema. DBSI also indicated better angular resolution compared with DKI, QBI and GQI.
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http://dx.doi.org/10.1002/nbm.4414DOI Listing
January 2021

Sex-specific association between infant caudate volumes and a polygenic risk score for major depressive disorder.

J Neurosci Res 2020 12 9;98(12):2529-2540. Epub 2020 Sep 9.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Turku, Finland.

Polygenic risk scores for major depressive disorder (PRS-MDD) have been identified in large genome-wide association studies, and recent findings suggest that PRS-MDD might interact with environmental risk factors to shape human limbic brain development as early as in the prenatal period. Striatal structures are crucially involved in depression; however, the association of PRS-MDD with infant striatal volumes is yet unknown. In this study, 105 Finnish mother-infant dyads (44 female, 11-54 days old) were investigated to reveal how infant PRS-MDD is associated with infant dorsal striatal volumes (caudate, putamen) and whether PRS-MDD interacts with prenatal maternal depressive symptoms (Edinburgh Postnatal Depression Scale, gestational weeks 14, 24, 34) on infant striatal volumes. A robust sex-specific main effect of PRS-MDD on bilateral infant caudate volumes was observed. PRS-MDD were more positively associated with caudate volumes in boys compared to girls. No significant interaction effects of genotype PRS-MDD with the environmental risk factor "prenatal maternal depressive symptoms" (genotype-by-environment interaction) nor significant interaction effects of genotype with prenatal maternal depressive symptoms and sex (genotype-by-environment-by-sex interaction) were found for infant dorsal striatal volumes. Our study showed that a higher PRS-MDD irrespective of prenatal exposure to maternal depressive symptoms is associated with smaller bilateral caudate volumes, an indicator of greater susceptibility to major depressive disorder, in female compared to male infants. This sex-specific polygenic effect might lay the ground for the higher prevalence of depression in women compared to men.
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http://dx.doi.org/10.1002/jnr.24722DOI Listing
December 2020

Newborn amygdalar volumes are associated with maternal prenatal psychological distress in a sex-dependent way.

Neuroimage Clin 2020 11;28:102380. Epub 2020 Aug 11.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Institute of Clinical Medicine University of Turku, Turku, Finland; Department of Psychiatry, University of Turku and Turku University Hospital, Turku, Finland; Center for Population Health Research, University of Turku and Turku University Hospital, Finland.

Maternal psychological distress during pregnancy (PPD) has been associated with changes in offspring amygdalar and hippocampal volumes. Studies on child amygdalae suggest that sex moderates the vulnerability of fetal brains to prenatal stress. However, this has not yet been observed in these structures in newborns. Newborn studies are crucial, as they minimize the confounding influence of postnatal life. We investigated the effects of maternal prenatal psychological symptoms on newborn amygdalar and hippocampal volumes and their interactions with newborn sex in 123 newborns aged 2-5 weeks (69 males, 54 females). Based on earlier studies, we anticipated small, but statistically significant effects of PPD on the volumes of these structures. Maternal psychological distress was measured at gestational weeks (GW) 14, 24 and 34 using Symptom Checklist-90 (SCL-90, anxiety scale) and Edinburgh Postnatal Depression Scale (EPDS) questionnaires. Newborn sex was found to moderate the relationship between maternal distress symptoms at GW 24 and the volumes of left and right amygdala. This relationship was negative and significant only in males. No significant main effect or sex-based moderation was found for hippocampal volumes. This newborn study provides evidence for a sex-dependent influence of maternal psychiatric symptoms on amygdalar structural development. This association may be relevant to later psychopathology.
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http://dx.doi.org/10.1016/j.nicl.2020.102380DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453059PMC
August 2020

Added value of systematic biopsy in men with a clinical suspicion of prostate cancer undergoing biparametric MRI-targeted biopsy: multi-institutional external validation study.

World J Urol 2020 Aug 10. Epub 2020 Aug 10.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Purpose: We aimed to develop and externally validate a nomogram based on MRI volumetric parameters and clinical information for deciding when SBx should be performed in addition to TBx in man with suspicious prostate MRI.

Materials And Methods: Retrospective analyses of single (IMPROD, NCT01864135) and multi-institution (MULTI-IMPROD, NCT02241122) clinical trials. All men underwent a unique rapid biparametric magnetic resonance imaging (IMPROD bpMRI) consisting of T2-weighted imaging and three separate DWI acquisitions. Men with IMPROD bpMRI Likert scores of 3-5 were included. Logistic regression models were developed using IMPROD trial (n = 122) and validated using MULTI-IMPROD trial (n = 262) data. The model's performance was evaluated in the terms of PCa detection with Gleason Grade Group 1 (clinically insignificant prostate cancer, iPCa) and > 1 (clinically significant prostate cancer, csPCa). Net benefits and decision curve analyses (DCA) were compared. Combined biopsies were used for reference.

Results: The developed nomogram included age, PSA, prostate volume, MRI suspicion score (IMPROD bpMRI Likert or PIRADsv2.1 score), MRI-suspicion lesion volume percentage, and lesion location. All these variables were significant predictors of csPCa in SBx in multivariable analysis. In the validation cohort (n = 262) using different nomogram cutoffs, 19-43% of men would have avoided SBx while missing 1-4% of csPCa and avoiding detection of 9-20% of iPCa. Similar performance was found for nomograms using IMPROD bpMRI Likert score or v2.1.

Conclusions: The developed nomogram demonstrated potential to select men with a clinical suspicion of PCa who would benefit from performing SBx in addition to TBx. Public access to the nomogram is provided at: https://petiv.utu.fi/multiimprod/ .
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http://dx.doi.org/10.1007/s00345-020-03393-8DOI Listing
August 2020

Test-retest repeatability of a deep learning architecture in detecting and segmenting clinically significant prostate cancer on apparent diffusion coefficient (ADC) maps.

Eur Radiol 2021 Jan 23;31(1):379-391. Epub 2020 Jul 23.

Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.

Objectives: To evaluate short-term test-retest repeatability of a deep learning architecture (U-Net) in slice- and lesion-level detection and segmentation of clinically significant prostate cancer (csPCa: Gleason grade group > 1) using diffusion-weighted imaging fitted with monoexponential function, ADC.

Methods: One hundred twelve patients with prostate cancer (PCa) underwent 2 prostate MRI examinations on the same day. PCa areas were annotated using whole mount prostatectomy sections. Two U-Net-based convolutional neural networks were trained on three different ADC b value settings for (a) slice- and (b) lesion-level detection and (c) segmentation of csPCa. Short-term test-retest repeatability was estimated using intra-class correlation coefficient (ICC(3,1)), proportionate agreement, and dice similarity coefficient (DSC). A 3-fold cross-validation was performed on training set (N = 78 patients) and evaluated for performance and repeatability on testing data (N = 34 patients).

Results: For the three ADC b value settings, repeatability of mean ADC of csPCa lesions was ICC(3,1) = 0.86-0.98. Two CNNs with U-Net-based architecture demonstrated ICC(3,1) in the range of 0.80-0.83, agreement of 66-72%, and DSC of 0.68-0.72 for slice- and lesion-level detection and segmentation of csPCa. Bland-Altman plots suggest that there is no systematic bias in agreement between inter-scan ground truth segmentation repeatability and segmentation repeatability of the networks.

Conclusions: For the three ADC b value settings, two CNNs with U-Net-based architecture were repeatable for the problem of detection of csPCa at the slice-level. The network repeatability in segmenting csPCa lesions is affected by inter-scan variability and ground truth segmentation repeatability and may thus improve with better inter-scan reproducibility.

Key Points: • For the three ADC b value settings, two CNNs with U-Net-based architecture were repeatable for the problem of detection of csPCa at the slice-level. • The network repeatability in segmenting csPCa lesions is affected by inter-scan variability and ground truth segmentation repeatability and may thus improve with better inter-scan reproducibility.
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http://dx.doi.org/10.1007/s00330-020-07065-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821380PMC
January 2021

Newborn white matter microstructure moderates the association between maternal postpartum depressive symptoms and infant negative reactivity.

Soc Cogn Affect Neurosci 2020 07;15(6):649-660

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Turku, Finland.

Maternal postpartum depression is a prominent risk factor for aberrant child socioemotional development, but there is little understanding about the neural phenotypes that underlie infant sensitivity to maternal depression. We examined whether newborn white matter fractional anisotropy (FA), a measure of white matter maturity, moderates the association between maternal postpartum depressive symptoms and infant negative reactivity at 6 months. Participants were 80 mother-infant dyads participating in a prospective population-based cohort, and included families whose newborns underwent a magnetic resonance/diffusion tensor imaging scan at 2-5 weeks of age and whose mothers reported their own depressive symptoms at 3 and 6 months postpartum and infant negative emotional reactivity at 6 months. The whole-brain FA moderated the association between maternal depressive symptoms and mother-reported infant negative reactivity at 6 months after adjusting for the covariates. Maternal depressive symptoms were positively related to infant negative reactivity among infants with high or average FA in the whole brain and in corpus callosum and cingulum, but not among those with low FA. The link between maternal depressive symptoms and infant negative reactivity was moderated by newborn FA. The variation in white matter microstructure might play a role in child susceptibility to parental distress.
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http://dx.doi.org/10.1093/scan/nsaa081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7393309PMC
July 2020

Prediction of prostate cancer aggressiveness using F-Fluciclovine (FACBC) PET and multisequence multiparametric MRI.

Sci Rep 2020 06 10;10(1):9407. Epub 2020 Jun 10.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

The aim of this prospective single-institution clinical trial (NCT02002455) was to evaluate the potential of advanced post-processing methods for F-Fluciclovine PET and multisequence multiparametric MRI in the prediction of prostate cancer (PCa) aggressiveness, defined by Gleason Grade Group (GGG). 21 patients with PCa underwent PET/CT, PET/MRI and MRI before prostatectomy. DWI was post-processed using kurtosis (ADC, K), mono- (ADC), and biexponential functions (f, D, D) while Logan plots were used to calculate volume of distribution (V). In total, 16 unique PET (V, SUV) and MRI derived quantitative parameters were evaluated. Univariate and multivariate analysis were carried out to estimate the potential of the quantitative parameters and their combinations to predict GGG 1 vs >1, using logistic regression with a nested leave-pair out cross validation (LPOCV) scheme and recursive feature elimination technique applied for feature selection. The second order rotating frame imaging (RAFF), monoexponential and kurtosis derived parameters had LPOCV AUC in the range of 0.72 to 0.92 while the corresponding value for V was 0.85. he best performance for GGG prediction was achieved by K parameter of kurtosis function followed by quantitative parameters based on DWI, RAFF and F-FACBC PET. No major improvement was achieved using parameter combinations with or without feature selection. Addition of F-FACBC PET derived parameters (V, SUV) to DWI and RAFF derived parameters did not improve LPOCV AUC.
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http://dx.doi.org/10.1038/s41598-020-66255-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7287051PMC
June 2020

Negative Predictive Value of Biparametric Prostate Magnetic Resonance Imaging in Excluding Significant Prostate Cancer: A Pooled Data Analysis Based on Clinical Data from Four Prospective, Registered Studies.

Eur Urol Focus 2020 May 14. Epub 2020 May 14.

Department of Urology, University of Turku and Turku University hospital, Turku, Finland.

Background: Multiparametric prostate magnetic resonance imaging (mpMRI) can be considered the gold standard in prostate magnetic resonance imaging (MRI). Biparametric prostate MRI (bpMRI) is faster and could be a feasible alternative to mpMRI.

Objective: To determine the negative predictive value (NPV) of Improved Prostate Cancer Diagnosis (IMPROD) bpMRI as a whole and in clinical subgroups in primary diagnostics of clinically significant prostate cancer (CSPCa).

Design, Setting, And Participants: This is a pooled data analysis of four prospective, registered clinical trials investigating prebiopsy IMPROD bpMRI. Men with a clinical suspicion of prostate cancer (PCa) were included.

Intervention: Prebiopsy IMPROD bpMRI was performed, and an IMPROD bpMRI Likert scoring system was used. If suspicious lesions (IMPROD bpMRI Likert score 3-5) were visible, targeted biopsies in addition to systematic biopsies were taken.

Outcome Measurements And Statistical Analysis: Performance measures of IMPROD bpMRI in CSPCa diagnostics were evaluated. NPV was also evaluated in clinical subgroups. Gleason grade ≥3 + 4 in any biopsy core taken was defined as CSPCa.

Results And Limitations: A total of 639 men were included in the analysis. The mean age was 64 yr, mean prostate-specific antigen level was 8.9 ng/ml, and CSPCa prevalence was 48%. NPVs of IMPROD bpMRI Likert scores 3-5 and 4-5 for CSPCa were 0.932 and 0.909, respectively, and the corresponding positive predictive values were 0.589 and 0.720. Only nine of 132 (7%) men with IMPROD bpMRI Likert score 1-2 had CSPCa and none with Gleason score >7. Thus, 132 of 639 (21%) study patients could have avoided biopsies without missing a single Gleason >7 cancer in the study biopsies. In the subgroup analysis, no clear outlier was present. The limitation is uncertainty of the true CSPCa prevalence.

Conclusions: IMPROD bpMRI demonstrated a high NPV to rule out CSPCa. IMPROD bpMRI Likert score 1-2 excludes Gleason >7 PCa in the study biopsies.

Patient Summary: We investigated the feasibility of prostate magnetic resonance imaging (MRI) with the Improved Prostate Cancer Diagnosis (IMPROD) biparametric MRI (bpMRI) protocol in excluding significant prostate cancer. In this study, highly aggressive prostate cancer was excluded using the publicly available IMPROD bpMRI protocol (http://petiv.utu.fi/multiimprod/).
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http://dx.doi.org/10.1016/j.euf.2020.04.007DOI Listing
May 2020

Resting-state networks of the neonate brain identified using independent component analysis.

Dev Neurobiol 2020 03 19;80(3-4):111-125. Epub 2020 Apr 19.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Institute of Clinical Medicine, University of Turku, Turku, Finland.

Resting-state functional magnetic resonance imaging (rs-fMRI) has been successfully used to probe the intrinsic functional organization of the brain and to study brain development. Here, we implemented a combination of individual and group independent component analysis (ICA) of FSL on a 6-min resting-state data set acquired from 21 naturally sleeping term-born (age 26 ± 6.7 d), healthy neonates to investigate the emerging functional resting-state networks (RSNs). In line with the previous literature, we found evidence of sensorimotor, auditory/language, visual, cerebellar, thalmic, parietal, prefrontal, anterior cingulate as well as dorsal and ventral aspects of the default-mode-network. Additionally, we identified RSNs in frontal, parietal, and temporal regions that have not been previously described in this age group and correspond to the canonical RSNs established in adults. Importantly, we found that careful ICA-based denoising of fMRI data increased the number of networks identified with group-ICA, whereas the degree of spatial smoothing did not change the number of identified networks. Our results show that the infant brain has an established set of RSNs soon after birth.
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http://dx.doi.org/10.1002/dneu.22742DOI Listing
March 2020

Prevalence and Risk Factors of Incidental Findings in Brain MRIs of Healthy Neonates-The FinnBrain Birth Cohort Study.

Front Neurol 2019 8;10:1347. Epub 2020 Jan 8.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Institute of Clinical Medicine, University of Turku, Turku, Finland.

Birth is a traumatic event with molding forces directed to the fetal skull, which may result in intracranial hemorrhages. However, the knowledge on prevalence and risk factors of incidental brain magnetic resonance imaging (MRI) findings in infants is still inconclusive. The prevalence and nature of incidental MRI findings were assessed in a birth cohort of 175 asymptomatic infants. The role of delivery method as well as other potential risk factors for intracranial hemorrhages were evaluated. The infants underwent 3T MRI at the age of 2-5 weeks, and the neurological status of the infants with an incidental finding was evaluated by a pediatric neurologist. Information on the delivery method, duration of delivery, parity, used anesthesia, oxytocin induction, and Apgar score was gathered to evaluate their association with the prevalence of hemorrhages. Incidental intracranial hemorrhages were detected in 12 infants (6.9%), all following spontaneous or assisted vaginal delivery. Vacuum-assistance was found to be a risk factor for subdural hemorrhages with an odds ratio (OR) of 4.7 (95% CI [1.18; 18.9], = 0.032). All infants were evaluated to develop normally by their clinical status. Incidental intracranial hemorrhages are relatively common among infants born by vaginal delivery. They are often of little clinical significance within the first years of life and have unlikely consequences for later neurodevelopment either. Despite their benign character, investigators should be prepared to share this information with parents competently as the findings can cause parental anxiety, and especially as the popularity of MRI as a research tool is increasing.
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http://dx.doi.org/10.3389/fneur.2019.01347DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6960102PMC
January 2020

Qualitative and Quantitative Reporting of a Unique Biparametric MRI: Towards Biparametric MRI-Based Nomograms for Prediction of Prostate Biopsy Outcome in Men With a Clinical Suspicion of Prostate Cancer (IMPROD and MULTI-IMPROD Trials).

J Magn Reson Imaging 2020 05 21;51(5):1556-1567. Epub 2019 Nov 21.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

Background: Multiparametric MRI of the prostate has been shown to improve the risk stratification of men with an elevated prostate-specific antigen (PSA). However, long acquisition time, high cost, and inter-center/reader variability of a routine prostate multiparametric MRI limit its wider adoption.

Purpose: To develop and validate nomograms based on unique rapid biparametric MRI (bpMRI) qualitative and quantitative derived variables for prediction of clinically significant cancer (SPCa).

Study Type: Retrospective analyses of single (IMPROD, NCT01864135) and multiinstitution trials (MULTI-IMPROD, NCT02241122).

Population: 161 and 338 prospectively enrolled men who completed the IMPROD and MULTI-IMPROD trials, respectively.

Field Strength/sequence: IMPROD bpMRI: 3T/1.5T, T -weighted imaging, three separate diffusion-weighted imaging (DWI) acquisitions: 1) b-values 0, 100, 200, 300, 500 s/mm ; 2) b values 0, 1500 s/mm ; 3) values 0, 2000 s/mm .

Assessment: The primary endpoint of the combined trial analysis was the diagnostic accuracy of the combination of IMPROD bpMRI and clinical variables for detection of SPCa.

Statistical Tests: Logistic regression models were developed using IMPROD trial data and validated using MULTI-IMPROD trial data. The model's performance was expressed as the area under the curve (AUC) values for the detection of SPCa, defined as ISUP Gleason Grade Group ≥2.

Results: A model incorporating clinical variables had an AUC (95% confidence interval) of 0.83 (0.77-0.89) and 0.80 (0.75-0.85) in the development and validation cohorts, respectively. The corresponding values for a model using IMPROD bpMRI findings were 0.93 (0.89-0.97), and 0.88 (0.84-0.92), respectively. Further addition of the quantitative DWI-based score did not improve AUC values (P < 0.05).

Data Conclusion: A prediction model using qualitative IMPROD bpMRI findings demonstrated high accuracy for predicting SPCa in men with an elevated PSA. Online risk calculator: http://petiv.utu.fi/multiimprod/ Level of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1556-1567.
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http://dx.doi.org/10.1002/jmri.26975DOI Listing
May 2020

Repeatability of radiomics and machine learning for DWI: Short-term repeatability study of 112 patients with prostate cancer.

Magn Reson Med 2020 06 8;83(6):2293-2309. Epub 2019 Nov 8.

Department of Diagnostic Radiology, University of Turku, Turku, Finland.

Purpose: To evaluate repeatability of prostate DWI-derived radiomics and machine learning methods for prostate cancer (PCa) characterization.

Methods: A total of 112 patients with diagnosed PCa underwent 2 prostate MRI examinations (Scan1 and Scan2) performed on the same day. DWI was performed using 12 b-values (0-2000 s/mm ), post-processed using kurtosis function, and PCa areas were annotated using whole mount prostatectomy sections. A total of 1694 radiomic features including Sobel, Kirch, Gradient, Zernike Moments, Gabor, Haralick, CoLIAGe, Haar wavelet coefficients, 3D analogue to Laws features, 2D contours, and corner detectors were calculated. Radiomics and 4 feature pruning methods (area under the receiver operator characteristic curve, maximum relevance minimum redundancy, Spearman's ρ, Wilcoxon rank-sum) were evaluated in terms of Scan1-Scan2 repeatability using intraclass correlation coefficient (ICC)(3,1). Classification performance for clinically significant and insignificant PCa with Gleason grade groups 1 versus >1 was evaluated by area under the receiver operator characteristic curve in unseen random 30% data split.

Results: The ICC(3,1) values for conventional radiomics and feature pruning methods were in the range of 0.28-0.90. The machine learning classifications varied between Scan1 and Scan2 with % of same class labels between Scan1 and Scan2 in the range of 61-81%. Surface-to-volume ratio and corner detector-based features were among the most represented features with high repeatability, ICC(3,1) >0.75, consistently high ranking using all 4 feature pruning methods, and classification performance with area under the receiver operator characteristic curve >0.70.

Conclusion: Surface-to-volume ratio and corner detectors for prostate DWI led to good classification of unseen data and performed similarly in Scan1 and Scan2 in contrast to multiple conventional radiomic features.
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http://dx.doi.org/10.1002/mrm.28058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7047644PMC
June 2020

A Novel Approach for Manual Segmentation of the Amygdala and Hippocampus in Neonate MRI.

Front Neurosci 2019 24;13:1025. Epub 2019 Sep 24.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Institute of Clinical Medicine, University of Turku, Turku, Finland.

The gross anatomy of the infant brain at term is fairly similar to that of the adult brain, but structures are immature, and the brain undergoes rapid growth during the first 2 years of life. Neonate magnetic resonance (MR) images have different contrasts compared to adult images, and automated segmentation of brain magnetic resonance imaging (MRI) can thus be considered challenging as less software options are available. Despite this, most anatomical regions are identifiable and thus amenable to manual segmentation. In the current study, we developed a protocol for segmenting the amygdala and hippocampus in T2-weighted neonatal MR images. The participants were 31 healthy infants between 2 and 5 weeks of age. Intra-rater reliability was measured in 12 randomly selected MR images, where 6 MR images were segmented at 1-month intervals between the delineations, and another 6 MR images at 6-month intervals. The protocol was also tested by two independent raters in 20 randomly selected T2-weighted images, and finally with T1 images. Intraclass correlation coefficient (ICC) and Dice similarity coefficient (DSC) for intra-rater, inter-rater, and T1 vs. T2 comparisons were computed. Moreover, manual segmentations were compared to automated segmentations performed by iBEAT toolbox in 10 T2-weighted MR images. The intra-rater reliability was high ICC ≥ 0.91, DSC ≥ 0.89, the inter-rater reliabilities were satisfactory ICC ≥ 0.90, DSC ≥ 0.75 for hippocampus and DSC ≥ 0.52 for amygdalae. Segmentations for T1 vs. T2-weighted images showed high consistency ICC ≥ 0.90, DSC ≥ 0.74. The manual and iBEAT segmentations showed no agreement, DSC ≥ 0.39. In conclusion, there is a clear need to improve and develop the procedures for automated segmentation of infant brain MR images.
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http://dx.doi.org/10.3389/fnins.2019.01025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6768976PMC
September 2019

Prostate Cancer Risk Stratification in Men With a Clinical Suspicion of Prostate Cancer Using a Unique Biparametric MRI and Expression of 11 Genes in Apparently Benign Tissue: Evaluation Using Machine-Learning Techniques.

J Magn Reson Imaging 2020 05 6;51(5):1540-1553. Epub 2019 Oct 6.

Institute of Biomedicine, University of Turku and Department of Pathology, Turku University Hospital, Turku, Finland.

Background: Accurate risk stratification of men with a clinical suspicion of prostate cancer (cSPCa) remains challenging despite the increasing use of MRI.

Purpose: To evaluate the diagnostic accuracy of a unique biparametric MRI protocol (IMPROD bpMRI) combined with clinical and molecular markers in men with cSPCa.

Study Type: Prospective single-institutional clinical trial (NCT01864135).

Subjects: Eighty men with cSPCa.

Field Strength/sequence: 3T, surface array coils. Two T -weighted and three diffusion-weighted imaging (DWI) acquisitions: 1) b-values 0, 100, 200, 300, 500 s/mm ; 2) b-values 0,1500 s/mm ; 3) b-values 0, 2000 s/mm .

Assessment: IMPROD bpMRI examinations were qualitatively (IMPROD bpMRI Likert score) and quantitatively (DWI-based Gleason grade score) prospectively reported. Men with IMPROD bpMRI Likert 3-5 had two targeted biopsies followed by 12-core systematic biopsies (SB); those with IMPROD bpMRI Likert 1-2 had only SB. Additionally, 2-core from normal-appearing prostate areas were obtained for the mRNA expression of ACSM1, AMACR, CACNA1D, DLX1, PCA3, PLA2G7, RHOU, SPINK1, SPON2, TMPRSS2-ERG, and TDRD1 measured by quantitative reverse-transcription polymerase chain reaction.

Statistical Tests: Univariate and multivariate analysis using regularized least-squares, feature selection and tournament leave-pair-out cross-validation (TLPOCV), as well as 10 random splits of the data in training-testing sets, were used to evaluate the mRNA, clinical and IMPROD bpMRI parameters in detecting clinically significant prostate cancer (SPCa) defined as Gleason score ≥ 3 + 4. The evaluation metric was the area under the curve (AUC).

Results: IMPROD bpMRI Likert demonstrated the highest TLPOCV AUC of 0.92. The tested clinical variables had AUC 0.56-0.73, while the mRNA and additional IMPROD bpMRI parameters had AUC 0.50-0.67 and 0.65-0.89 respectively. The combination of clinical and mRNA biomarkers produced TLPOCV AUC of 0.87, the highest TLPOCV performance without including IMPROD bpMRI Likert.

Data Conclusion: The qualitative IMPROD bpMRI Likert score demonstrated the highest accuracy for SPCa detection compared with the tested clinical variables and mRNA biomarkers.

Level Of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1540-1553.
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http://dx.doi.org/10.1002/jmri.26945DOI Listing
May 2020

Prediction of biochemical recurrence in prostate cancer patients who underwent prostatectomy using routine clinical prostate multiparametric MRI and decipher genomic score.

J Magn Reson Imaging 2020 04 30;51(4):1075-1085. Epub 2019 Sep 30.

Department of Urology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

Background: Biochemical recurrence (BCR) affects a significant proportion of patients who undergo robotic-assisted laparoscopic prostatectomy (RALP).

Purpose: To evaluate the performance of a routine clinical prostate multiparametric magnetic resonance imaging (mpMRI) and Decipher genomic classifier score for prediction of biochemical recurrence in patients who underwent RALP.

Study Type: Retrospective cohort study.

Subjects: Ninety-one patients who underwent RALP performed by a single surgeon, had mpMRI before RALP, Decipher taken from RALP samples, and prostate specific antigen (PSA) follow-up for >3 years or BCR within 3 years, defined as PSA >0.2 mg/ml. FIELD STRENGTH/SEQUENCE: mpMRI was performed at 27 different institutions using 1.5T (n = 10) or 3T scanners and included T w, diffusion-weighted imaging (DWI), or dynamic contrast-enhanced (DCE) MRI.

Assessment: All mpMRI studies were reported by one reader using Prostate Imaging Reporting and Data System v. 2.1 (PI-RADsv2.1) without knowledge of other findings. Eighteen (20%) randomly selected cases were re-reported by reader B to evaluate interreader variability.

Statistical Tests: Univariate and multivariate analysis using greedy feature selection and tournament leave-pair-out cross-validation (TLPOCV) were used to evaluate the performance of various variables for prediction of BCR, which included clinical (three), systematic biopsy (three), surgical (six: RALP Gleason Grade Group [GGG], extracapsular extension, seminal vesicle invasion, intraoperative surgical margins [PSM], final PSM, pTNM), Decipher (two: Decipher score, Decipher risk category), and mpMRI (eight: prostate volume, PSA density, PI-RADv2.1 score, MRI largest lesion size, summed MRI lesions' volume and relative volume [MRI-lesion-percentage], mpMRI ECE, mpMRI seminal vesicle invasion [SVI]) variables. The evaluation metric was the area under the curve (AUC).

Results: Forty-eight (53%) patients developed BCR. The best-performing individual features with TLPOCV AUC of 0.73 (95% confidence interval [CI] 0.64-0.82) were RALP GGG, MRI-lesion-percentage followed by biopsy GGG (0.72, 0.62-0.82), and Decipher score (0.71, 0.60-0.82). The best performance was achieved by feature selection of Decipher+Surgery and MRI + Surgery variables with TLPOCV AUC of 0.82 and 0.81, respectively DATA CONCLUSION: Relative lesion volume measured on a routine clinical mpMRI failed to outperform Decipher score in BCR prediction.

Level Of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1075-1085.
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http://dx.doi.org/10.1002/jmri.26928DOI Listing
April 2020

Prebiopsy IMPROD Biparametric Magnetic Resonance Imaging Combined with Prostate-Specific Antigen Density in the Diagnosis of Prostate Cancer: An External Validation Study.

Eur Urol Oncol 2020 10 6;3(5):648-656. Epub 2019 Sep 6.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Background: Biparametric magnetic resonance imaging (bpMRI) combined with prostate-specific antigen density (PSAd) may be an effective strategy for selecting men for prostate biopsy. It has been shown that performing biopsy only for men with bpMRI Likert scores of 4-5 or PSAd ≥0.15 ng/ml/cm is the most efficient strategy.

Objective: To externally validate previously published biopsy strategies using two prospective bpMRI trial cohorts.

Design, Setting, And Participants: After IMPROD bpMRI, 499 men had systematic transrectal prostate biopsies and men with IMPROD bpMRI Likert scores of 3-5 had an additional two to four targeted biopsies.

Outcome Measurements And Statistical Analysis: Various IMPROD bpMRI Likert score and PSAd thresholds were assessed using detection rates for significant prostate cancer (sPCa; Gleason score ≥3 + 4), predictive values, and proportion of biopsies avoided. Net benefits and decision curve analyses (DCA) were compared with the aim of finding an optimal strategy for sPCa detection. Combined biopsies were used for reference.

Results And Limitations: The negative predictive value (NPV) for sPCa in IMPROD bpMRI Likert 3-5 and 4-5 score groups was 93% and 92%, respectively, while the corresponding positive predictive value (PPV) was 57% and 72%, respectively. In DCA, the optimal combination was IMPROD bpMRI Likert score 4-5 or Likert 3 with PSAd ≥0.20 ng/ml/cm, which had NPV of 93% and PPV of 67%. Using this combination, 35% of the study patients would have avoided biopsies and 13 sPCas (6%, 13/229, of all sPCas diagnosed) would have been missed.

Conclusions: IMPROD bpMRI demonstrated a good NPV for sPCa. PSAd improved the NPV mainly among men with equivocal suspicion on IMPROD bpMRI. However, the additional value of PSAd was marginal: the NPV and PPV for IMPROD bpMRI Likert 4-5 score group were 92% and 72%, respectively, while the corresponding values for the best combination strategy were 93% and 67%.

Patient Summary: We investigated a rapid prostate magnetic resonance imaging protocol (IMPROD bpMRI) combined with prostate-specific antigen (PSA) density for detection of significant prostate cancer. Our results show that IMPROD bpMRI is a good diagnostic tool, but the additional value provided by PSA density is marginal.
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http://dx.doi.org/10.1016/j.euo.2019.08.008DOI Listing
October 2020

Radiomics and machine learning of multisequence multiparametric prostate MRI: Towards improved non-invasive prostate cancer characterization.

PLoS One 2019 8;14(7):e0217702. Epub 2019 Jul 8.

Dept. of Diagnostic Radiology, University of Turku, Turku, Finland.

Purpose: To develop and validate a classifier system for prediction of prostate cancer (PCa) Gleason score (GS) using radiomics and texture features of T2-weighted imaging (T2w), diffusion weighted imaging (DWI) acquired using high b values, and T2-mapping (T2).

Methods: T2w, DWI (12 b values, 0-2000 s/mm2), and T2 data sets of 62 patients with histologically confirmed PCa were acquired at 3T using surface array coils. The DWI data sets were post-processed using monoexponential and kurtosis models, while T2w was standardized to a common scale. Local statistics and 8 different radiomics/texture descriptors were utilized at different configurations to extract a total of 7105 unique per-tumor features. Regularized logistic regression with implicit feature selection and leave pair out cross validation was used to discriminate tumors with 3+3 vs >3+3 GS.

Results: In total, 100 PCa lesions were analysed, of those 20 and 80 had GS of 3+3 and >3+3, respectively. The best model performance was obtained by selecting the top 1% features of T2w, ADCm and K with ROC AUC of 0.88 (95% CI of 0.82-0.95). Features from T2 mapping provided little added value. The most useful texture features were based on the gray-level co-occurrence matrix, Gabor transform, and Zernike moments.

Conclusion: Texture feature analysis of DWI, post-processed using monoexponential and kurtosis models, and T2w demonstrated good classification performance for GS of PCa. In multisequence setting, the optimal radiomics based texture extraction methods and parameters differed between different image types.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217702PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6613688PMC
February 2020

Validation of IMPROD biparametric MRI in men with clinically suspected prostate cancer: A prospective multi-institutional trial.

PLoS Med 2019 06 3;16(6):e1002813. Epub 2019 Jun 3.

Department of Urology, University of Turku and Turku University Hospital, Turku, Finland.

Background: Magnetic resonance imaging (MRI) combined with targeted biopsy (TB) is increasingly used in men with clinically suspected prostate cancer (PCa), but the long acquisition times, high costs, and inter-center/reader variability of routine multiparametric prostate MRI limit its wider adoption.

Methods And Findings: The aim was to validate a previously developed unique MRI acquisition and reporting protocol, IMPROD biparametric MRI (bpMRI) (NCT01864135), in men with a clinical suspicion of PCa in a multi-institutional trial (NCT02241122). IMPROD bpMRI has average acquisition time of 15 minutes (no endorectal coil, no intravenous contrast use) and consists of T2-weighted imaging and 3 separate diffusion-weighed imaging acquisitions. Between February 1, 2015, and March 31, 2017, 364 men with a clinical suspicion of PCa were enrolled at 4 institutions in Finland. Men with an equivocal to high suspicion (IMPROD bpMRI Likert score 3-5) of PCa had 2 TBs of up to 2 lesions followed by a systematic biopsy (SB). Men with a low to very low suspicion (IMPROD bpMRI Likert score 1-2) had only SB. All data and protocols are freely available. The primary outcome of the trial was diagnostic accuracy-including overall accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value-of IMPROD bpMRI for clinically significant PCa (SPCa), which was defined as a Gleason score ≥ 3 + 4 (Gleason grade group 2 or higher). In total, 338 (338/364, 93%) prospectively enrolled men completed the trial. The accuracy and NPV of IMPROD bpMRI for SPCa were 70% (113/161) and 95% (71/75) (95% CI 87%-98%), respectively. Restricting the biopsy to men with equivocal to highly suspicious IMPROD bpMRI findings would have resulted in a 22% (75/338) reduction in the number of men undergoing biopsy while missing 4 (3%, 4/146) men with SPCa. The main limitation is uncertainty about the true PCa prevalence in the study cohort, since some of the men may have PCa despite having negative biopsy findings.

Conclusions: IMPROD bpMRI demonstrated a high NPV for SPCa in men with a clinical suspicion of PCa in this prospective multi-institutional clinical trial.

Trial Registration: ClinicalTrials.gov NCT02241122.
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http://dx.doi.org/10.1371/journal.pmed.1002813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6546206PMC
June 2019

Correlation between F-1-amino-3-fluorocyclobutane-1-carboxylic acid (F-fluciclovine) uptake and expression of alanine-serine-cysteine-transporter 2 (ASCT2) and L-type amino acid transporter 1 (LAT1) in primary prostate cancer.

EJNMMI Res 2019 May 31;9(1):50. Epub 2019 May 31.

Turku PET Centre, Turku, Finland.

Purpose: To evaluate the expression of alanine-serine-cysteine-transporter 2 (ASCT2) and L-type amino acid transporter1 (LAT1) in prostate cancer (PCa) and their impact on uptake of F-1-amino-3-fluorocyclobutane-1-carboxylic acid (F-fluciclovine) which is approved for the detection of recurrent PCa.

Methods: Twenty-five hormone-naïve patients with histologically confirmed PCa underwent PET/CT before prostatectomy. Dynamic imaging was performed immediately after injection of 368 ± 10 MBq of F-fluciclovine and the uptake in PCa was expressed as SUV at six sequential 4-min time frames and as tracer distribution volume (V) using Logan plots over 0-24 min. The expression of ASCT2 and LAT1 was studied with immunohistochemistry (IHC) on a tissue microarray (TMA) containing three cores per carcinoma lesion. The TMA slides were scored independently by two trained readers based on visual intensity of ASCT2/LAT1 expression on a four-tiered scale. The correlations between ASCT2/LAT1 staining intensity, SUVmax/V, and Gleason grade group (GGG) were assessed using Spearman's rank correlation coefficient (ρ).

Results: Forty tumor foci (> 0.5 mm in diameter, max. 3 per patient) were available for TMA. In visual scoring, low, moderate, and high staining intensity of ASCT2 was observed in 4 (10%), 24 (60%), and 12 (30%) tumors, respectively. No tumors showed high LAT1 staining intensity while moderate intensity was found in 10 (25%), 25 (63%) showed low, and the remaining 5 (12%) were negative for staining with LAT1. Tumors with GGG > 2 showed significantly higher uptake of F-fluciclovine and higher LAT1 staining intensity (p < 0.05). The uptake of F-fluciclovine correlated significantly with LAT1 expression (ρ = 0.39, p = 0.01, for SUV at 2 min and ρ = 0.39, p = 0.01 for V). No correlation between ASCT2 expression and F-fluciclovine uptake or GGG was found.

Conclusions: Our findings suggest that LAT1 is moderately associated with the transport of F-fluciclovine in local PCa not exposed to hormonal therapy. Both high and low Gleason grade tumors express ASCT2 while LAT1 expression is less conspicuous and may be absent in some low-grade tumors. Our observations may be of importance when using F-fluciclovine imaging in the planning of focal therapies for PCa.
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http://dx.doi.org/10.1186/s13550-019-0518-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544711PMC
May 2019

Test-retest reliability of Diffusion Tensor Imaging metrics in neonates.

Neuroimage 2019 08 25;197:598-607. Epub 2019 Apr 25.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Institute of Clinical Medicine, University of Turku, Turku, Finland; Department of Psychiatry, University of Turku and Turku University Hospital, Turku, Finland.

Diffusion tensor imaging (DTI) has been widely used in children and adults to study the microstructural features of the brain. Its use in neonate brains has been limited. Neonate brains are almost completely unmyelinated, and this together with the tendency for babies to move during a scanning session may affect the reliability of the measurements. Here we divided a 96 direction acquisition into three segments, and analysed the intra scan test-retest reliability for pairs of segments. Each segment was subjected to a rigorous quality control, and from the surviving data we chose 25 diffusion encoding directions from each segment, and assessed the pairwise reliability of the most common DTI metrics. This pairwise reliability was assessed for data from 86 infants. We used tract-based spatial statistics (TBSS), voxelwise and ROI analysis schemes, to see potential differential effects of analysis strategy and post processing on the obtained DTI metrics. We found that intra class correlation coefficient (ICC) values were generally high (ICC > 0.80). Residual motion in the data, after quality control, was not found to associate with the diffusion metrics. The results indicate that DTI metrics from neonate data can be reliable, even at relatively low angular resolution that are common for neonate scans. The results lend confidence to the use of neonate DTI data in cross sectional and longitudinal analyses in brain white matter skeleton. Future studies should assess the reliability of fiber tracking techniques in neonate data.
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http://dx.doi.org/10.1016/j.neuroimage.2019.04.067DOI Listing
August 2019

IMPROD biparametric MRI in men with a clinical suspicion of prostate cancer (IMPROD Trial): Sensitivity for prostate cancer detection in correlation with whole-mount prostatectomy sections and implications for focal therapy.

J Magn Reson Imaging 2019 11 22;50(5):1641-1650. Epub 2019 Mar 22.

Institute of Biomedicine, University of Turku and Department of Pathology, Turku University Hospital, Turku, Finland.

Background: Prostate MRI is increasingly being used in men with a clinical suspicion of prostate cancer (PCa). However, development and validation of methods for focal therapy planning are still lagging.

Purpose: To evaluate the diagnostic accuracy on lesion, region-of-interest (ROI), and voxel level of IMPROD biparametric prostate MRI (bpMRI) for PCa detection in men with a clinical suspicion of PCa who subsequently underwent radical prostatectomy.

Study Type: Prospective single-institution clinical trial (NCT01864135).

Population: Sixty-four men who underwent radical prostatectomy after IMPROD bpMRI performed in prebiopsy settings.

Field Strength/sequence: IMPROD bpMRI consisted of T -weighted imaging (T w) and three separate diffusion-weighted imaging acquisitions with an average acquisition time of 15 minutes.

Assessment: The diagnostic accuracy of prospectively reported manual cancer delineations and regions increased with 3D dilation were evaluated on the voxel level (volume of 1.17 mm , 1 mm , 125 mm ) as well as the 36 ROI level. Only PCa lesions with a diameter ≥ 5 mm or any Gleason Grade 4 were analyzed. All data and protocols are freely available at: http://petiv.utu.fi/improd STATISTICAL TESTS: Sensitivity, specificity, accuracy.

Results: In total, 99 PCa lesions were identified. Forty (40%, 40/99) had a Gleason score (GS) of >3 + 4. Twenty-eight PCa lesions (28%, 28/99) were missed by IMPROD bpMRI, three (7.5%, 3/40) with GS >3 + 4. 3D dilation of manual cancer delineations in all directions by ~10-12 mm (corresponding to the Hausdorff distance) was needed to achieve sensitivity approaching 100% on a voxel level.

Data Conclusion: IMPROD bpMRI had a high sensitivity on lesion level for PCa with GS >3 + 4. Increasing 3D lesion delineations by ~10-12 mm (corresponding to the Hausdorff distance) was needed to achieve high sensitivity on the voxel level. Such information may help in planning ablation therapies.

Level Of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1641-1650.
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http://dx.doi.org/10.1002/jmri.26727DOI Listing
November 2019

Prenatal exposures and infant brain: Review of magnetic resonance imaging studies and a population description analysis.

Hum Brain Mapp 2019 04 19;40(6):1987-2000. Epub 2018 Nov 19.

FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Institute of Clinical Medicine, University of Turku, Turku, Finland.

Brain development is most rapid during the fetal period and the first years of life. This process can be affected by many in utero factors, such as chemical exposures and maternal health characteristics. The goal of this review is twofold: to review the most recent findings on the effects of these prenatal factors on the developing brain and to qualitatively assess how those factors were generally reported in studies on infants up to 2 years of age. To capture the latest findings in the field, we searched articles from PubMed 2012 onward with search terms referring to magnetic resonance imaging (MRI), brain development, and infancy. We identified 19 MRI studies focusing on the effects of prenatal environment and summarized them to highlight the recent advances in the field. We assessed population descriptions in a representative sample of 67 studies and conclude that prenatal factors that have been shown to affect brain metrics are not generally reported comprehensively. Based on our findings, we propose some improvements for population descriptions to account for plausible confounders and in time enable reliable meta-analyses to be performed. This could help the pediatric neuroimaging field move toward more reliable identification of biomarkers for developmental outcomes and to better decipher the nuances of normal and abnormal brain development.
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http://dx.doi.org/10.1002/hbm.24480DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6865387PMC
April 2019

Sex difference in brain CB1 receptor availability in man.

Neuroimage 2019 01 5;184:834-842. Epub 2018 Oct 5.

Turku PET Centre, Turku University Hospital, Finland; Department of Psychiatry, University of Turku and Turku University Hospital, Finland. Electronic address:

The endocannabinoid system (ECS) has a widespread neuromodulatory function in the central nervous system and is involved in important aspects of brain function including brain development, cortical rhythms, plasticity, reward, and stress sensitivity. Many of these effects are mediated via the cannabinoid CB1 receptor (CB1R) subtype. Animal studies convincingly show an interaction between the ECS and sex hormones, as well as a sex difference of higher brain CB1R in males. Human in vivo studies of sex difference have yielded discrepant findings. Gender differences in CB1R availability were investigated in vivo in 11 male and 11 female healthy volunteers using a specific CB1R tracer [F]FMPEP-d2 and positron emission tomography (PET). Regional [F]FMPEP-d2 distribution volume was used as a proxy for CB1R availability. In addition, we explored whether CB1R availability is linked to neuropsychological functioning. Relative to females, CB1R availability was on average 41% higher in males (p = 0.002) with a regionally specific effect larger in the posterior cingulate and retrosplenial cortices (p = 0.001). Inter-subject variability in CB1R availability was similar in both groups. Voxel-based analyses revealed an inverse association between CB1R availability and visuospatial working memory task performance in both groups (p < 0.001). A CB1R sex difference with a large effect size was observed and should be considered in the design of CB1R-related studies on neuropsychiatric disorders. The behavioural correlates and clinical significance of this difference remain to be further elucidated, but our studies suggest an association between CB1R availability and working memory.
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http://dx.doi.org/10.1016/j.neuroimage.2018.10.013DOI Listing
January 2019

C-acetate PET/MRI in bladder cancer staging and treatment response evaluation to neoadjuvant chemotherapy: a prospective multicenter study (ACEBIB trial).

Cancer Imaging 2018 Aug 2;18(1):25. Epub 2018 Aug 2.

Department of Urology, University of Turku and Turku University hospital, Kiinamyllynkatu 4-8, 20520, Turku, Finland.

Background: To evaluate the accuracy of C-acetate Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) in bladder cancer (BC) staging and monitoring response to neoadjuvant chemotherapy (NAC).

Methods: Eighteen patients were prospectively enrolled. Fifteen treatment naive patients underwent C-acetate PET/MRI before transurethral resection of bladder tumor (TUR-BT) for primary tumor evaluation. Five patients with muscle invasive BC were imaged after NAC and prior to radical cystectomy (RC) with extended pelvic lymph node dissection (ePLND) for NAC treatment response evaluation. Two patients were part of both cohorts. C-acetate PET/MRI findings were correlated with histopathology. Accuracy for lymph node detection was evaluated on patient and the ePLND template (10 regions) levels.

Results: The sensitivity, specificity and accuracy of C-acetate PET/MRI for the detection of muscle invasive BC was 1.00, 0.69 and 0.73 while the area under the receiver operating characteristic curve (95% confidence interval) was 0.85 (0.55-1.0), respectively. All five NAC patients underwent chemotherapy as planned and C-acetate PET/MRI correctly staged three patients, overstaged one and understaged one patient compared with RC and ePLND findings. A total of 175 lymph node were removed, median of 35 (range, 27-43) per patient in five patients who had RC and ePLND while 12 (7%) harboured metastases. Sensitivity, specificity, accuracy and AUC for N-staging were 0.20, 0.96, 0.80 and 0.58 on the ePLND template (10 regions) level.

Conclusions: C-acetate PET/MRI is feasible for staging of BC although sensitivity for the detection of nodal metastases is low. Monitoring response to NAC shows promise and warrants evaluation in larger studies.

Trial Registration: ClinicalTrials.gov Identifier: NCT01918592 , registered August 8 2013.
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http://dx.doi.org/10.1186/s40644-018-0158-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6090957PMC
August 2018

Neural correlates of gentle skin stroking in early infancy.

Dev Cogn Neurosci 2019 02 24;35:36-41. Epub 2017 Oct 24.

Center for Social and Affective Neuroscience, Linköping University, Sweden; Institute of Neuroscience and Physiology, University of Gothenburg, Sweden. Electronic address:

Physical expressions of affection play a foundational role in early brain development, but the neural correlates of affective touch processing in infancy remain unclear. We examined brain responses to gentle skin stroking, a type of tactile stimulus associated with affectionate touch, in young infants. Thirteen term-born infants aged 11-36days, recruited through the FinnBrain Birth Cohort Study, were included in the study. Soft brush strokes, which activate brain regions linked to somatosensory as well as socio-affective processing in children and adults, were applied to the skin of the right leg during functional magnetic resonance imaging. We examined infant brain responses in two regions-of-interest (ROIs) known to process gentle skin stroking - the postcentral gyrus and posterior insular cortex - and found significant responses in both ROIs. These results suggest that the neonate brain is responsive to gentle skin stroking within the first weeks of age, and that regions linked to primary somatosensory as well as socio-affective processing are activated. Our findings support the notion that social touch may play an important role in early life sensory processing. Future research will elucidate the significance of these findings for human brain development.
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http://dx.doi.org/10.1016/j.dcn.2017.10.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6968958PMC
February 2019