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Hannu Aronen

Publications and source records attributed to Hannu Aronen.

5 recordsLinked to original sources
PubMed2026

Lifestyle, anthropometric factors and clinically significant prostate cancer diagnosis in men with suspected prostate cancer.

OBJECTIVE: Lifestyle and anthropometric factors may influence prostate cancer (PCa) risk, yet evidence remains inconclusive. This study reports the associations between lifestyle and anthropometric factors and clinically significant PCa (csPCa; ISUP grade > 1) among men with clinical suspicion of PCa. MATERIALS AND METHODS: In this registered (NCT06116851), single-institution, prospective cohort trial, men referred for PCa diagnostics due to elevated prostate-specific antigen or abnormal digital rectal examination were included. Subjects underwent prostate diagnostics and completed detailed surveys of lifestyle, medical and family history. Physical activity was measured using a triaxial accelerometer. Anthropometric assessments included body mass index, waist circumference and magnetic resonance imaging-based body composition analyses. RESULTS: Among 298 included men, 143 (48%) were diagnosed with csPCa. In multivariate logistic regression, higher physical activity, measured by step count (odds ratio [OR]: 0.91, 95% confidence interval [CI]: 0.82-0.99) and active smoking compared to never-smokers (OR: 0.38, 95% CI: 0.14-0.96) were inversely associated with detection of csPCa. Higher prostate-specific antigen density was associated with increased risk (OR: 1.78, 95% CI: 1.39-2.35). Body composition was not associated with csPCa. Study strengths include comprehensive data collection. Primary limitation is partial reliance on self-reported data. CONCLUSIONS: Higher measured physical activity was inversely associated with detection of csPCa in men with suspicion of PCa. Active smoking also showed an inverse association. Both findings merit further investigation.

Aged↗
PubMed2006

Effect of using local arterial input functions on cerebral blood flow estimation.

PURPOSE: To investigate a previously developed method for perfusion-weighted MRI (PWI) cerebral blood flow (CBF) estimation that uses local arterial input functions (AIFs) in stroke patients, and determine its ability to correct delay and/or dispersion (D/D) errors. MATERIALS AND METHODS: Analysis was performed on dynamic susceptibility contrast data from 36 stroke patients, and CBF maps were calculated with global- and local-AIF techniques using standard SVP based methods. The ratios of these maps were calculated and the mean ratios were calculated for voxels with both normal and abnormal time to peak or width. The locations of the voxels with high locally-defined to globally-defined CBF ratios were also mapped and the average underlying concentration-time curves for these voxels were calculated. RESULTS: The ratio of CBF estimates based on local AIFs to global AIFs was on average increased for D/D voxels. The voxels in which this ratio was high were commonly concentrated in the ipsilateral hemisphere, and these voxels also displayed underlying concentration-time curves that showed delay or dispersion. Conversely, there were no such findings based on high globally-defined to locally-defined CBF ratios. CONCLUSION: The local-AIF technique results in an increase in the calculated CBF values for tissues with D/D, consistent with a reduction in the errors associated with D/D.

Adult↗
PubMed2006

Automated perfusion-weighted MRI using localized arterial input functions.

PURPOSE: To investigate the utility of an automated perfusion-weighted MRI (PWI) method for estimating cerebral blood flow (CBF) based on localized arterial input functions (AIFs) as compared to the standard method of manual global AIF selection, which is prone to deconvolution errors due to the effects of delay and dispersion of the contrast bolus. MATERIALS AND METHODS: Analysis was performed on spin- and gradient-echo EPI images from 36 stroke patients. A local AIF algorithm created an AIF for every voxel in the brain by searching out voxels with the lowest delay and dispersion, and then interpolating and spatially smoothing them for continuity. A generalized linear model (GLM) for predicting tissue outcome, and MTT lesion volumes were used to quantify the performance of the localized AIF method in comparison with global methods using ipsilateral and contralateral AIFs. RESULTS: The algorithm found local AIFs in each case without error and generated a higher area under the receiver operating characteristic (ROC) curve compared to both global-AIF methods. Similarly, the local MTT lesion volumes had the least mean squared error (MSE). CONCLUSION: Automated CBF calculation using local AIFs is feasible and appears to produce more useful CBF maps.

Adult↗
PubMed2003

MnDPDP-enhanced magnetization transfer MR imaging: implications for effective liver imaging.

The benefit of combining magnetization transfer (MT) MR imaging technique with liver-specific contrast agent manganese dipyridoxyldiphosphate (MnDPDP) was assessed in our experimental investigation. The study was accomplished by imaging a phantom containing serial concentrations of MnDPDP in cross-linked bovine serum albumin (BSA) with various protein concentrations. A 0.1T clinical MR imager with different parameters for MT and conventional MR sequences were used. The combination of an offset frequency of 8 kHz and an amplitude of 25 microT produced nearly maximal MT effect for all protein samples either without MnDPDP or with different MnDPDP concentrations. With long TRs (TR > 200 ms) MT dramatically improved CNR in conjunction with MnDPDP. With short TRs, the gain in CNR with MT was negligible. However, long TRs with increased number of images are beneficial in liver imaging. We conclude that MT like preparation pulse is useful when paramagnetic contrast agents such as MnDPDP are employed.

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