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314
Age, gender, and ethnicity effects on NET availability in humans using [11C]MRB [Meeting Abstract]
Objectives: Alzheimer's disease (AD) is a major health challenge in our aging society. An improved understanding of its underlying pathological mechanisms is urgently needed to enable the development of effective treatments. Postmortem findings indicate that tau pathology emerges decades before amyloid pathology, appearing first in the brainstem; in particular in the locus coeruleus (LC), a small nucleus that is the source of most of the brain's norepinephrine (NE). Although very little is known about how the NE system changes during normal aging and its potential role in progression of preclinical stages of AD, our preliminary data using (S,S)-[11C]MRB ([11C]MRB) have documented an age-related decline in NE transporters (NET) availability starting in middle age, suggesting in vivo NET availability is a sensitive biomarker for aging and for changes during the preclinical stages of AD. In addition to the age effect, this report investigated the potential gender and ethnicity effects on NET availability.
Method(s): Dynamic [11C]MRB images of healthy subjects were acquired for 120 min and individual structure MRI images were acquired for co-registration purposes. The segmentation of cortical and subcortical ROIs was automatically established via FreeSurfer (https://urldefense.proofpoint.com/v2/url?u=https-3A__surfer.nmr.mgh.harvard.edu_&d=DwIBAg&c=j5oPpO0eBH1iio48DtsedeElZfc04rx3ExJHeIIZuCs&r=CY_mkeBghQnUPnp2mckgsNSbUXISJaiBQUhM-Uz9W58&m=_uGsTvUTTD_GxqvwK245ZUiiSbzVraIboytFijFDOwU&s=HeAlDPi40HjMBca8e_BYWUls-gTNztvS9BIGKcmzNNI&e= ) based on the template MRI atlas (FS2005). Left and right olfactory (Ofac) regions were also generated using the Destrieux Atlas. With Firevoxel developed at NYU (https://urldefense.proofpoint.com/v2/url?u=https-3A__wp.nyu.edu_Firevoxel&d=DwIBAg&c=j5oPpO0eBH1iio48DtsedeElZfc04rx3ExJHeIIZuCs&r=CY_mkeBghQnUPnp2mckgsNSbUXISJaiBQUhM-Uz9W58&m=_uGsTvUTTD_GxqvwK245ZUiiSbzVraIboytFijFDOwU&s=RlC-AQtmqr84rzBwvDmgK_FCVdvbCfsFvuN-dVODTpM&e= ), PET, MRI, and the FS atlas images of each individual were coregistered using a mutual information algorithm with autofocus transformation that was tested and validated. Dynamic regional time-activity curves (TAC) were generated and MRTM2 was selected as the modeling method. Binding potential (BPND, a measure of specific binding with respect to non-displaceable uptake) values were automatically calculated, and tested by various starting time, parameter k2' and using two potential reference regions (caudate & occipital, low NET regions), for comparison and validation purposes. Annual percent change (APC) of regional BPND values was calculated based on linear regression (APC = 100 x (e - 1), m is the slope) and effects of age, gender and ethnicity on the NET-MRB binding were evaluated.
Result(s): Data presented here were based on t2* 20 min and k2' 0.021 min with occi as the reference region. For all HC (N=31), with both genders and all race included, the NET availability decline can be observed; e.g., -0.4%/yr for BS & ROfac. However, in gender-separated group analysis [M (N=19, age range: 23-55, avg=36.2+/-9.9) and F (N=12, age range 25-54, avg= 36.6+/-9.0)], while BPND values were not significantly different, there was a significant gender effect for APC (P <0.01) with decline rates faster for M (e.g., -0.8, -0.6, -0.5, & -0.4%/yr for TH, RAmyg, ROfac, & Hip, respectively), and significant decline starting from mid 30 (p<0.001). Gender effects were also observed in the group-level analyses in all white (N=16, 11M) and in all AA subgroups (N=14, 7M) with the decline rate faster for M than F, but APC difference did not reach significance (may be due to sample size and age range not completely matched). Interestingly, out of all investigated brain ROIs (16), avg BPND values of each ROI from AA (N=14, avg age 34+/-7) were consistently higher than those from white subjects (N=12, avg age 35+/-8)(P<0.000). However, the decline rate was consistently higher for AA than for white subjects (P<0.00001), e.g., the decline rate for AA-M: -3%/yr in LTH & RAmyg and over -1%/yr in BS & ROfac, and for AA-F: -2%/yr in BS & Ofac.
Conclusion(s): Compared to our previous age-related study of dopamine transporter (DAT), NET exhibited a faster decline rate than DAT. In addition to our previously determined age effect on MRB-NET binding, this report further reveals the role of gender and ethnicity effects on NET availability. A bigger sample size is warranted to investigate their effects on the NET availability
Method(s): Dynamic [11C]MRB images of healthy subjects were acquired for 120 min and individual structure MRI images were acquired for co-registration purposes. The segmentation of cortical and subcortical ROIs was automatically established via FreeSurfer (https://urldefense.proofpoint.com/v2/url?u=https-3A__surfer.nmr.mgh.harvard.edu_&d=DwIBAg&c=j5oPpO0eBH1iio48DtsedeElZfc04rx3ExJHeIIZuCs&r=CY_mkeBghQnUPnp2mckgsNSbUXISJaiBQUhM-Uz9W58&m=_uGsTvUTTD_GxqvwK245ZUiiSbzVraIboytFijFDOwU&s=HeAlDPi40HjMBca8e_BYWUls-gTNztvS9BIGKcmzNNI&e= ) based on the template MRI atlas (FS2005). Left and right olfactory (Ofac) regions were also generated using the Destrieux Atlas. With Firevoxel developed at NYU (https://urldefense.proofpoint.com/v2/url?u=https-3A__wp.nyu.edu_Firevoxel&d=DwIBAg&c=j5oPpO0eBH1iio48DtsedeElZfc04rx3ExJHeIIZuCs&r=CY_mkeBghQnUPnp2mckgsNSbUXISJaiBQUhM-Uz9W58&m=_uGsTvUTTD_GxqvwK245ZUiiSbzVraIboytFijFDOwU&s=RlC-AQtmqr84rzBwvDmgK_FCVdvbCfsFvuN-dVODTpM&e= ), PET, MRI, and the FS atlas images of each individual were coregistered using a mutual information algorithm with autofocus transformation that was tested and validated. Dynamic regional time-activity curves (TAC) were generated and MRTM2 was selected as the modeling method. Binding potential (BPND, a measure of specific binding with respect to non-displaceable uptake) values were automatically calculated, and tested by various starting time, parameter k2' and using two potential reference regions (caudate & occipital, low NET regions), for comparison and validation purposes. Annual percent change (APC) of regional BPND values was calculated based on linear regression (APC = 100 x (e - 1), m is the slope) and effects of age, gender and ethnicity on the NET-MRB binding were evaluated.
Result(s): Data presented here were based on t2* 20 min and k2' 0.021 min with occi as the reference region. For all HC (N=31), with both genders and all race included, the NET availability decline can be observed; e.g., -0.4%/yr for BS & ROfac. However, in gender-separated group analysis [M (N=19, age range: 23-55, avg=36.2+/-9.9) and F (N=12, age range 25-54, avg= 36.6+/-9.0)], while BPND values were not significantly different, there was a significant gender effect for APC (P <0.01) with decline rates faster for M (e.g., -0.8, -0.6, -0.5, & -0.4%/yr for TH, RAmyg, ROfac, & Hip, respectively), and significant decline starting from mid 30 (p<0.001). Gender effects were also observed in the group-level analyses in all white (N=16, 11M) and in all AA subgroups (N=14, 7M) with the decline rate faster for M than F, but APC difference did not reach significance (may be due to sample size and age range not completely matched). Interestingly, out of all investigated brain ROIs (16), avg BPND values of each ROI from AA (N=14, avg age 34+/-7) were consistently higher than those from white subjects (N=12, avg age 35+/-8)(P<0.000). However, the decline rate was consistently higher for AA than for white subjects (P<0.00001), e.g., the decline rate for AA-M: -3%/yr in LTH & RAmyg and over -1%/yr in BS & ROfac, and for AA-F: -2%/yr in BS & Ofac.
Conclusion(s): Compared to our previous age-related study of dopamine transporter (DAT), NET exhibited a faster decline rate than DAT. In addition to our previously determined age effect on MRB-NET binding, this report further reveals the role of gender and ethnicity effects on NET availability. A bigger sample size is warranted to investigate their effects on the NET availability
EMBASE:633250414
ISSN: 0161-5505
CID: 4657432
Standardized Brain MRI Acquisition Protocols Improve Statistical Power in Multicenter Quantitative Morphometry Studies
BACKGROUND AND PURPOSE/OBJECTIVE:In this study, we used power analysis to calculate required sample sizes to detect group-level changes in quantitative neuroanatomical estimates derived from MRI scans obtained from multiple imaging centers. Sample size estimates were derived from (i) standardized 3T image acquisition protocols and (ii) nonstandardized clinically acquired images obtained at both 1.5 and 3T as part of the multicenter Human Epilepsy Project. Sample size estimates were compared to assess the benefit of standardizing acquisition protocols. METHODS:Cortical thickness, hippocampal volume, and whole brain volume were estimated from whole brain T1-weighted MRI scans processed using Freesurfer v6.0. Sample sizes required to detect a range of effect sizes were calculated using (i) standard t-test based power analysis methods and (ii) a nonparametric bootstrap approach. RESULTS:A total of 32 participants were included in our analyses, aged 29.9 ± 12.62 years. Standard deviation estimates were lower for all quantitative neuroanatomical metrics when assessed using standardized protocols. Required sample sizes per group to detect a given effect size were markedly reduced when using standardized protocols, particularly for cortical thickness changes <.2 mm and hippocampal volume changes <10%. CONCLUSIONS:The use of standardized protocols yielded up to a five-fold reduction in required sample sizes to detect disease-related neuroanatomical changes, and is particularly beneficial for detecting subtle effects. Standardizing image acquisition protocols across scanners prior to commencing a study is a valuable approach to increase the statistical power of multicenter MRI studies.
PMID: 31664774
ISSN: 1552-6569
CID: 4163332
THE INFLUENCE OF OBSTRUCTIVE SLEEP APNEA SEVERITY AND SEX ON CEREBRAL PERFUSION [Meeting Abstract]
ISI:000554588500013
ISSN: 0161-8105
CID: 4562222
SUN-304 SMALL FIELD OF VIEW DIFFUSION TENSOR IMAGING (DTI) OF THE KIDNEYS IN PEOPLE WITH TYPE 2 DIABETES AND HEALTHY CONTROLS [Meeting Abstract]
Introduction: Traditional clinical markers of renal function are unreliable in people with early diabetic kidney disease (DKD). Diffusion tensor imaging (DTI) has potential to non-invasively measure kidney function in early kidney disease, reflecting changes in tubular microstructure. Changes in cortical fractional anisotropy (cFA), medullary fractional anisotropy (mFA) cortical mean diffusivity (cMD) and medullary mean diffusivity (mMD) have been reported in people with type 2 diabetes (T2DM), including people with normal renal function. Although promising, renal DTI is challenging due to susceptibility and motion artifacts. We test two technical innovations, small field of view (FOV) imaging and a motion correction algorithm. We assess inter-reader agreement and changes in T2DM of derived cFA, mFA, cMD, mMD.
Method(s): 4 people with T2DM (Table 1) and 9 healthy volunteers (1M, 8F, eGFR >90 ml/min/1.73m2) were recruited as part of a prospective study assessing impact of empagliflozin on functional MRI metrics in T2DM. [Figure presented] Free-breathing small FOV DTI (ZOOMit, Siemens Healthcare), blood oxygen level dependent imaging (BOLD) and conventional sequences were acquired at 3T (MAGNETOM Skyra, Siemens Healthcare), using b-values of 0, 150 and 500 s/mm2. Motion correction was performed (FireVoxel, NYUMC, NY) prior to creation of FA and MD maps (Fig 1). Two radiologists independently scored FA corticomedullary differentiation (1=poor, 4=excellent) measured cFA, mFA, cMD and mMD. [Figure presented] Inter-reader agreement was assessed using Lin's concordance correlation coefficient (LCCC). Volunteer and patient group differences and concordance with eGFR were assessed with random intercept regression analysis.
Result(s): All subjects successfully completed baseline DTI (Table 2). Lower corticomedullary differentiation scores (Mean+/-SD) were observed for people with T2DM (2.1+/-1.2) versus volunteers (3.0+/-0.8). [Figure presented] There was substantial inter-reader agreement for cFA and mFA (LCCC 0.76 and 0.74), and almost perfect agreement for cMD and mMD (LCCC 0.89 and 0.93). Mean cFA decreased by 0.021 (95% CI 0.011-0.032) and mean mFA decreased by 0.12 (95% CI 0.084-0.163) in people with T2DM (p<0.001), with no significant difference between groups for cMD and mMD. A 0.027 (95%CI 0.002 - 0.053) lower mFA was observed for every 10 ml/min/1.73m2 decrease in eGFR (p<0.001).No significant relationship between eGFR and cFA, cMD or mMD was observed.
Conclusion(s): Small FOV renal DTI is feasible with high inter-reader agreement for FA and MD. In this small pilot study, reduced corticomedullary differentiation and significantly lower medullary FA were demonstrated in people with T2DM compared to volunteers and lower medullary FA associated with lower eGFR, similar to the literature. Lower cortical FA in T2DM was an unexpected finding. Validation of these findings is planned in a larger population. Additional post-empagliflozin DTI and BOLD data will also be presented, which may offer further insight into diabetic kidney disease and management.
Copyright
Method(s): 4 people with T2DM (Table 1) and 9 healthy volunteers (1M, 8F, eGFR >90 ml/min/1.73m2) were recruited as part of a prospective study assessing impact of empagliflozin on functional MRI metrics in T2DM. [Figure presented] Free-breathing small FOV DTI (ZOOMit, Siemens Healthcare), blood oxygen level dependent imaging (BOLD) and conventional sequences were acquired at 3T (MAGNETOM Skyra, Siemens Healthcare), using b-values of 0, 150 and 500 s/mm2. Motion correction was performed (FireVoxel, NYUMC, NY) prior to creation of FA and MD maps (Fig 1). Two radiologists independently scored FA corticomedullary differentiation (1=poor, 4=excellent) measured cFA, mFA, cMD and mMD. [Figure presented] Inter-reader agreement was assessed using Lin's concordance correlation coefficient (LCCC). Volunteer and patient group differences and concordance with eGFR were assessed with random intercept regression analysis.
Result(s): All subjects successfully completed baseline DTI (Table 2). Lower corticomedullary differentiation scores (Mean+/-SD) were observed for people with T2DM (2.1+/-1.2) versus volunteers (3.0+/-0.8). [Figure presented] There was substantial inter-reader agreement for cFA and mFA (LCCC 0.76 and 0.74), and almost perfect agreement for cMD and mMD (LCCC 0.89 and 0.93). Mean cFA decreased by 0.021 (95% CI 0.011-0.032) and mean mFA decreased by 0.12 (95% CI 0.084-0.163) in people with T2DM (p<0.001), with no significant difference between groups for cMD and mMD. A 0.027 (95%CI 0.002 - 0.053) lower mFA was observed for every 10 ml/min/1.73m2 decrease in eGFR (p<0.001).No significant relationship between eGFR and cFA, cMD or mMD was observed.
Conclusion(s): Small FOV renal DTI is feasible with high inter-reader agreement for FA and MD. In this small pilot study, reduced corticomedullary differentiation and significantly lower medullary FA were demonstrated in people with T2DM compared to volunteers and lower medullary FA associated with lower eGFR, similar to the literature. Lower cortical FA in T2DM was an unexpected finding. Validation of these findings is planned in a larger population. Additional post-empagliflozin DTI and BOLD data will also be presented, which may offer further insight into diabetic kidney disease and management.
Copyright
EMBASE:2002179544
ISSN: 2468-0249
CID: 4024142
Prostate cancer heterogeneity: texture analysis score based on multiple MRI sequences for detection, stratification and selection of lesions at time of biopsy
PURPOSE/OBJECTIVE:To undertake an early proof of concept study on a novel, semi-automated texture-based scoring system in order to enhance the association between MRI lesions and clinically significant cancer. PATIENTS AND METHODS/METHODS:With ethics approval, 536 imaging volumes were generated from 20 consecutive patients who underwent mpMRI at time of biopsy. Volumes of interest (VOIs) included zonal anatomy segmentation and suspicious MRI lesion for cancer (Likert scale score greater than 2). Entropy (E), measuring heterogeneity, was computed from VOIs and plotted as a multiparametric score defined as Entropy Score (ES) = E ADC+ E Ktrans + E Ve+ E T2WI. The reference test that was used to define the ground truth comprised systematic saturation biopsies coupled with MRI targeted sampling. This generated 422 cores in all that were individually labelled and oriented in 3D. Diagnostic accuracy for detection of clinically significant prostate cancer (SPCa), defined as Gleason score of 3+4 (or higher) or more than 3mm of any grade of cancer on a single core, was assessed using Receiver Operating Characteristics, correlation and descriptive statistics. Proportion of cancerous lesions detected by ES and Visual Scoring (VS) were statistically compared using paired McNemar test. RESULTS:Any cancer (Gleason Score 6 to 8) was found in 12 of the 20 (60%) patients with a median PSA of 8.22ng/ml. SPCa (ES=17.96 ±0.72 NAT; CI 95%) showed a significant higher ES than non-SPCa (ES=15.33 ±0.76 NAT). ES correlated with Gleason Score (rs =0.5683, p=0.033) and maximum cancer core length (Ï = 0.781; p=0.0009). The Area Under the Curve for ES (0.89) and visual scoring (VS) (0.91) were not significantly different (p=0.75) for detection of SPCa among MRI lesions. Best ES estimated numerical threshold of 16.61 NATural information unit (NAT) led to a sensitivity of 100% and negative predictive value of 100%. The proportion of MRI lesion which found to positive for SPCa using this ES threshold (54%) was significantly higher (p<0.001) than those using VS (24% of score 3,4,5) in a paired analysis using McNemar test. 53% of MRI lesion would have avoided biopsy sampling without missing significant disease. CONCLUSION/CONCLUSIONS:Capturing heterogeneity of PCa across multiple MRI sequences with ES yielded high performances for the detection and stratification of SPca. ES outperformed visual scoring in predicting positivity of lesions, holding promise in the selection of targets for biopsy and calling for further understanding of this association.
PMID: 30378238
ISSN: 1464-410x
CID: 3401062
Precisely-Measured Hydration Status Correlates with Hippocampal Volume in Healthy Older Adults [Letter]
PMID: 30879941
ISSN: 1545-7214
CID: 3734792
Comparing quantitative measures of global and regional tau binding for 18F-AV-1451 PET scans [Meeting Abstract]
Objectives: Quantitative measurement of tau binding from PET tracers (such as AV-1451) is crucial in the PET-based study of tauopathies (such as Alzheimer's). The traditional standardized uptake value ratio (SUVR) method has been challenged by the off-target binding in reference region (Figure 1). Recently, several alternative methods have been proposed for unbiased tau binding quantification, including the Parametric Estimate of Reference Signal Intensity (PERSI) method and standardized uptake value peak-alignment (SUVP) method. In this study, we compared the normal/disease group difference and classification accuracy of SUVR, PERSI and SUVP measures, for both global and regional tau binding, on AV-1451 PET scans.
Method(s): PET and MRI images of 44 subjects were retrieved from the Alzheimer's Disease Neuroimaging Initiative database (ADNI), including 22 normal control (NL) and 22 Alzheimer's disease (AD), matched with age and gender. The MRI images were acquired with standard T1 MPRAGE sequence (240x256x176 matrix; 1.0x1.0 mm pixel; 1.2mm slice thickness). Using Freesurfer (v6.0), regions of interest (ROIs) were defined on MRI images for global and regional binding: cerebral cortex for global binding; and regions affected in Braak Stages (BS) for regional binding (Supplementary Data). The PET acquisition involves an intravenous injection of 370MBq AV-1451 followed by a saline flush. A continuous 30 min brain scan (6 frames, 5 min each) was performed ~75 min after the injection, followed by a CT or transmission scan for attenuation correction. PET scans were reconstructed using a 3-D OSEM algorithm (four iterations, 12 subsets, 5 mm FWHM, 128x128 matrix, 3mm slice thickness). The 80-100 min summed images of PET scan were used to generate the standardized uptake value (SUV) maps, and then co-registered to the MRI images. The SUVR measure was computed by dividing the average SUV of ROI by the average SUV of reference region (cerebellar cortex). The PERSI measure replaced the reference region in SUVR measure by fitting a bimodal gaussian distributionto to the white matter SUV histogram, and using the center and width of the lower-intensity peak to identify the voxels to be included. The SUVP measure involves a transformation on the raw SUV maps: SUVP=(SUV-M)/S, where M and S are the mode and standard deviation of the whole brain SUV distribution. The average positive SUVP (SUVP-AVG) can then be computed by averaging all positive (i.e. >0) SUVP values of an ROI; and positive binding percentage for SUVP (SUVP-PBP) were computed by the ratio of voxel number with SUVP>1.5 over the total voxel number of the ROI. All binding measures were log-transformed, and tested for group differences with two-sample T-tests. The disease classification accuracy was estimated with the area under curve (AUC) of the Receiver Operating Characteristic (ROC) curve.
Result(s): As expected, AD subjects showed higher tau binding than NL, both globally and regionally, under all measures (Figure 2). For regional bidding, BS 3-4 regions (including temporal lobe) showed most prominent group difference and highest classification accuracy (AUC=0.85 for SUVP-AVG, SUVP-PBP and PERSI, AUC=0.79 for SUVR). This is consistent with previous reports for AV-1451 scans. For global binding and binding of BS 5-6 regions, SUVP achieved highest classification accuracy (AUC>0.88 for global, AUC>0.81 for BS 5-6 regions), seconded by PERSI (AUC=0.81 for global, AUC=0.76 for BS 5-6 regions), and then SUVR (AUC=0.76 for global, AUC=0.72 for BS 5-6 regions).
Conclusion(s): All three quantification methods detected the group difference of tau binding between AD and NL. Both PERSI and SUVP showed classification improvement over SUVR. SUVP achieved equal or higher classification accuracy than PERSI in global, BS 3-4, and BS 5-6 regional binding. These results have potential value for the quantitative measures of other tau PET scans, as well as Amyloid PET scans
Method(s): PET and MRI images of 44 subjects were retrieved from the Alzheimer's Disease Neuroimaging Initiative database (ADNI), including 22 normal control (NL) and 22 Alzheimer's disease (AD), matched with age and gender. The MRI images were acquired with standard T1 MPRAGE sequence (240x256x176 matrix; 1.0x1.0 mm pixel; 1.2mm slice thickness). Using Freesurfer (v6.0), regions of interest (ROIs) were defined on MRI images for global and regional binding: cerebral cortex for global binding; and regions affected in Braak Stages (BS) for regional binding (Supplementary Data). The PET acquisition involves an intravenous injection of 370MBq AV-1451 followed by a saline flush. A continuous 30 min brain scan (6 frames, 5 min each) was performed ~75 min after the injection, followed by a CT or transmission scan for attenuation correction. PET scans were reconstructed using a 3-D OSEM algorithm (four iterations, 12 subsets, 5 mm FWHM, 128x128 matrix, 3mm slice thickness). The 80-100 min summed images of PET scan were used to generate the standardized uptake value (SUV) maps, and then co-registered to the MRI images. The SUVR measure was computed by dividing the average SUV of ROI by the average SUV of reference region (cerebellar cortex). The PERSI measure replaced the reference region in SUVR measure by fitting a bimodal gaussian distributionto to the white matter SUV histogram, and using the center and width of the lower-intensity peak to identify the voxels to be included. The SUVP measure involves a transformation on the raw SUV maps: SUVP=(SUV-M)/S, where M and S are the mode and standard deviation of the whole brain SUV distribution. The average positive SUVP (SUVP-AVG) can then be computed by averaging all positive (i.e. >0) SUVP values of an ROI; and positive binding percentage for SUVP (SUVP-PBP) were computed by the ratio of voxel number with SUVP>1.5 over the total voxel number of the ROI. All binding measures were log-transformed, and tested for group differences with two-sample T-tests. The disease classification accuracy was estimated with the area under curve (AUC) of the Receiver Operating Characteristic (ROC) curve.
Result(s): As expected, AD subjects showed higher tau binding than NL, both globally and regionally, under all measures (Figure 2). For regional bidding, BS 3-4 regions (including temporal lobe) showed most prominent group difference and highest classification accuracy (AUC=0.85 for SUVP-AVG, SUVP-PBP and PERSI, AUC=0.79 for SUVR). This is consistent with previous reports for AV-1451 scans. For global binding and binding of BS 5-6 regions, SUVP achieved highest classification accuracy (AUC>0.88 for global, AUC>0.81 for BS 5-6 regions), seconded by PERSI (AUC=0.81 for global, AUC=0.76 for BS 5-6 regions), and then SUVR (AUC=0.76 for global, AUC=0.72 for BS 5-6 regions).
Conclusion(s): All three quantification methods detected the group difference of tau binding between AD and NL. Both PERSI and SUVP showed classification improvement over SUVR. SUVP achieved equal or higher classification accuracy than PERSI in global, BS 3-4, and BS 5-6 regional binding. These results have potential value for the quantitative measures of other tau PET scans, as well as Amyloid PET scans
EMBASE:629439852
ISSN: 1535-5667
CID: 4119182
Different Relationship Between Systolic Blood Pressure and Cerebral Perfusion in Subjects With and Without Hypertension
Although there is an increasing agreement that hypertension is associated with cerebrovascular compromise, relationships between blood pressure (BP) and cerebral blood flow are not fully understood. It is not known what BP level, and consequently what therapeutic goal, is optimal for brain perfusion. Moreover, there is limited data on how BP affects hippocampal perfusion, a structure critically involved in memory. We conducted a cross-sectional (n=445) and longitudinal (n=185) study of adults and elderly without dementia or clinically apparent stroke, who underwent clinical examination and brain perfusion assessment (age 69.2±7.5 years, 62% women, 45% hypertensive). Linear models were used to test baseline BP-blood flow relationship and to examine how changes in BP influence changes in perfusion. In the entire group, systolic BP (SBP) was negatively related to cortical (β=-0.13, P=0.005) and hippocampal blood flow (β=-0.12, P=0.01). Notably, this negative relationship was apparent already in subjects without hypertension. Hypertensive subjects showed a quadratic relationship between SBP and hippocampal blood flow (β=-1.55, P=0.03): Perfusion was the highest in subjects with mid-range SBP around 125 mm Hg. Longitudinally, in hypertensive subjects perfusion increased with increased SBP at low baseline SBP but increased with decreased SBP at high baseline SBP. Cortical and hippocampal perfusion decrease with increasing SBP across the entire BP spectrum. However, in hypertension, there seems to be a window of mid-range SBP which maximizes perfusion.
PMID: 30571554
ISSN: 1524-4563
CID: 3556742
Multimodal Hippocampal Subfield Grading For Alzheimer's Disease Classification
ISI:000487586600036
ISSN: 2045-2322
CID: 4155602
Accuracy and precision of quantitative DCE-MRI parameters: How should one estimate contrast concentration?
INTRODUCTION/BACKGROUND:-weighted DCE-MRI. MATERIALS AND METHODS/METHODS:) and arterial input function (AIF). In addition, the effect of the conversion method on the diagnostic accuracy was evaluated with 36 breast lesions (19 benign and 17 malignant). RESULTS:. CONCLUSION/CONCLUSIONS:measurement is not available and a low FA is used for DCE-MRI, the uncertainty in the contrast kinetic parameter estimation can be reduced by using the LC method with pAIF, without compromising the diagnostic accuracy.
PMCID:6102067
PMID: 29777820
ISSN: 1873-5894
CID: 3121612
