scholarly journals Longitudinal tau PET using [18F]flortaucipir: Comparison of (semi)quantitative parameters

2021 ◽  
Author(s):  
Denise Visser ◽  
Hayel Tuncel ◽  
Rik Ossenkoppele ◽  
Maqsood Yaqub ◽  
Emma E Wolters ◽  
...  
Keyword(s):  
Blood Flow ◽  
Specific Binding ◽  
Region Of Interest ◽  
Accurate Estimate ◽  
Subjective Cognitive Decline ◽  
Quantitative Pet ◽  
Flow Changes ◽  
Tau Pet ◽  
Pet Scans

Purpose: Semi-quantitative PET measures can be affected by changes in blood flow, whereas quantitative measures are not. The aim of the study was to compare semi-quantitative(SUVr) and quantitative(R1, BPND) parameters of longitudinal tau PET scans with [18F]flortaucipir, with respect to changes in blood flow. Methods: Subjects with subjective cognitive decline(SCD; n=38) and Alzheimer′s disease(AD) patients(n=24) underwent baseline(BL) and 2-year follow-up(FU) dynamic [18F]flortaucipir PET scans. BPND and R1 were estimated using RPM and SUVr(80-100min) was calculated (cerebellar gray as reference). For each region-of-interest ((trans)entorhinal, limbic and neocortical) and parameter, %change was calculated. Regional SUVrs were compared to corresponding DVR (= BPND+1) using paired T-tests. Additionally, simulations were performed to model effects of flow changes on BPND and SUVr in different binding categories. Thereafter, %bias for SUVr with respect to underlying binding and flow were evaluated. Results: In SCD, there was a difference between %change in the (trans)entorhinal ROI (DVR 2.56% vs SUVr 1.85%) only. In AD, a difference was found in the limbic ROI (DVR 6.61% vs SUVr 7.52%) only. R1 changes were small(+0.7% in SCD and -1.6% in AD). Simulations illustrated with increasing flow a decreased %bias for SUVr in low binding conditions, whereas a slightly increased bias was observed in high binding conditions. Conclusion: SUVr provided an accurate estimate of specific binding for [18F]flortaucipir over a two-year follow-up. However, simulations showed that flow changes can affect [18F]flortaucipir SUVr, hence DVR/BPND should be preferred in more advanced disease stages and/or conditions that could induce significant flow changes like pharmacotherapeutic interventions.

scholarly journals Assessment of choriocapillary blood flow changes in response to half-dose photodynamic therapy in chronic central serous chorioretinopathy using optical coherence tomography angiography

2020 ◽  
Author(s):  
Juejun Liu ◽  
Changzheng Chen ◽  
Lu Li ◽  
Yishuang Xu ◽  
Zuohuizi Yi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Photodynamic Therapy ◽  
Central Serous Chorioretinopathy ◽  
Optical Coherence Tomography Angiography ◽  
Optical Coherence ◽  
Chronic Central Serous Chorioretinopathy ◽  
Half Dose ◽  
Flow Changes

Abstract Background: Optical coherence tomography angiography (OCTA) is a newly developed imaging quantitative technique for analysis of choriocapillaris (CC) flow changes, thereby exploring the pathological mechanism of chronic central serous chorioretinopathy (CCSC) and the therapeutic effects of photodynamic therapy (PDT). In this study, we sought to quantify the blood flow changes in CC of CCSC patients receiving half-dose PDT using OCTA.Methods: A total of 28 affected eyes and 24 unaffected eyes of 26 CCSC patients receiving half-dose PDT, and 40 eyes of 20 healthy gender- and age-matched subjects were retrospectively enrolled in this study. The proportion of total areas of flow signal voids (FSV, %) in CC level of OCTA was assessed in both eyes of the CCSC patients at baseline and repeated in multiple sections at 1-week, 1-month, 3-month and 6-month intervals after PDT. In addition, the CC patterns in response to PDT at early stage and the subsequent morphologic changes were qualitatively documented using OCTA.Results: For affected eyes, FSV at 6-m follow-up was significantly lower than that at 1-m follow-up (p=0.036). When compared to normal control eyes, FSV in affected eyes was significantly higher at 1-m, 3-m and 6-m follow-up (p<0.05 for all), and FSV in unaffected eyes was significantly higher at baseline, 1-w, 1-m and 3-m follow-up (p<0.05 for all). Three CC patterns of early response to PDT were identified, including signs of recovery with more even flow signals, transient appearance of worse ischemia and secondary neovascularization within CC level.Conclusion: Abnormal CC flow attenuation remains in completely resolved eyes of CCSC patients treated with half-dose PDT.

scholarly journals Assessment of choriocapillary blood flow changes in response to half-dose photodynamic therapy in chronic central serous chorioretinopathy using optical coherence tomography angiography

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Juejun Liu ◽  
Changzheng Chen ◽  
Lu Li ◽  
Yishuang Xu ◽  
Zuohuizi Yi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Photodynamic Therapy ◽  
Central Serous Chorioretinopathy ◽  
Optical Coherence Tomography Angiography ◽  
Optical Coherence ◽  
Chronic Central Serous Chorioretinopathy ◽  
Half Dose ◽  
Flow Changes

Abstract Background Optical coherence tomography angiography (OCTA) is a newly developed imaging quantitative technique for analysis of choriocapillaris (CC) flow changes, thereby exploring the pathological mechanism of chronic central serous chorioretinopathy (CCSC) and the therapeutic effects of photodynamic therapy (PDT). In this study, we sought to quantify the blood flow changes in CC of CCSC patients receiving half-dose PDT using OCTA. Methods A total of 28 affected eyes and 24 unaffected eyes of 26 CCSC patients receiving half-dose PDT, and 40 eyes of 20 healthy gender- and age-matched subjects were retrospectively enrolled in this study. The proportion of total areas of flow signal voids (FSV, %) in CC level of OCTA was assessed in both eyes of the CCSC patients at baseline and repeated in multiple sections at 1-week, 1-month, 3-month and 6-month intervals after PDT. In addition, the CC patterns in response to PDT at early stage and the subsequent morphologic changes were qualitatively documented using OCTA. Results For affected eyes, FSV at 6-m follow-up was significantly lower than that at 1-m follow-up (p = 0.036). When compared to normal control eyes, FSV in affected eyes was significantly higher at 1-m, 3-m and 6-m follow-up (p < 0.05 for all), and FSV in unaffected eyes was significantly higher at baseline, 1-w, 1-m and 3-m follow-up (p < 0.05 for all). Three CC patterns of early response to PDT were identified, including signs of recovery with more even flow signals, transient appearance of worse ischemia and secondary neovascularization within CC level. Conclusion Abnormal CC flow attenuation remains in completely resolved eyes of CCSC patients treated with half-dose PDT.

SPECT Follow-Up Study of Cerebral Blood Flow Changes During Donepezil Therapy in Patients with Alzheimer's Disease

2006 ◽  
Vol 16 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Soichiro Shimizu ◽  
Haruo Hanyu ◽  
Toshihiko Iwamoto ◽  
Kiyoshi Koizumi ◽  
Kimihiko Abe
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Follow Up Study ◽  
Flow Changes

scholarly journals Assessment of choriocapillary blood flow changes in response to half-dose PDT in chronic central serous chorioretinopathy using OCTA

2020 ◽  
Author(s):  
Juejun Liu ◽  
Changzheng Chen ◽  
Lu Li ◽  
Yishuang Xu ◽  
Zuohuizi Yi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Central Serous Chorioretinopathy ◽  
Early Stage ◽  
Early Response ◽  
Therapeutic Effects ◽  
Chronic Central Serous Chorioretinopathy ◽  
Half Dose ◽  
Flow Changes

Abstract Background: Optical coherence tomography angiography (OCTA) is a principally new imaging technique that provide quantitative method to analyze choriocapillaris (CC) flow changes, while assessment of CC in vivo could be valuable in understanding the pathological mechanism of chronic central serous chorioretinopathy (CCSC) and the therapeutic effects of photodynamic therapy (PDT). In this study, we sought to quantify blood flow changes in CC of CCSC patients receiving half-dose PDT using OCTA.Methods: A total of 28 affected eyes and 24 unaffected eyes of 26 CCSC patients receiving half-dose PDT, and 40 eyes of 20 healthy gender- and age-matched subjects were retrospectively enrolled. The proportion of total areas of flow signal voids (FSV, %) in CC level of OCTA was assessed in both eyes of the CCSC patients at baseline and repeated in multiple sections at 1-week, 1-month, 3-month and 6-month intervals after PDT. In addition, CC patterns in response to PDT at early stage and their subsequent morphologic changes were qualitatively documented using OCTA. Results: For affected eyes, significant decrease in FSV was found at 6-m follow-up when compared with that at 1-m follow-up (p=0.036). When compared to normal control eyes, FSV in affected eyes was significantly higher at 1-m, 3-m and 6-m follow-up (p<0.05 for all), while FSV in unaffected eyes was significantly higher at baseline, 1-w, 1-m and 3-m follow-up (p<0.05 for all). Three CC patterns of early response to PDT were identified, including signs of recovery with more even flow signals, transient appearance of worse ischemia and secondary neovascularization within CC level.Conclusion: Abnormal CC flow attenuation remains in completely resolved eyes of CCSC patients treated with half-dose PDT.

scholarly journals Cerebral Blood Flow Measurement Using fMRI and PET: A Cross-Validation Study

2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
Jean J. Chen ◽  
Marguerite Wieckowska ◽  
Ernst Meyer ◽  
G. Bruce Pike
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Visual Stimulation ◽  
Region Of Interest ◽  
Experimental Conditions ◽  
Noninvasive Technique ◽  
Significant Difference ◽  
Brain Hemodynamics ◽  
Flow Changes

An important aspect of functional magnetic resonance imaging (fMRI) is the study of brain hemodynamics, and MR arterial spin labeling (ASL) perfusion imaging has gained wide acceptance as a robust and noninvasive technique. However, the cerebral blood flow (CBF) measurements obtained with ASL fMRI have not been fully validated, particularly during global CBF modulations. We present a comparison of cerebral blood flow changes (ΔCBF) measured using a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion method to those obtained usingH2O15PET, which is the current gold standard for in vivo imaging of CBF. To study regional and global CBF changes, a group of 10 healthy volunteers were imaged under identical experimental conditions during presentation of 5 levels of visual stimulation and one level of hypercapnia. The CBF changes were compared using 3 types of region-of-interest (ROI) masks. FAIR measurements of CBF changes were found to be slightly lower than those measured with PET (averageΔCBF of21.5±8.2% for FAIR versus28.2±12.8% for PET at maximum stimulation intensity). Nonetheless, there was a strong correlation between measurements of the two modalities. Finally, at-test comparison of the slopes of the linear fits of PET versus ASLΔCBF for all 3 ROI types indicated no significant difference from unity (P>.05).

scholarly journals Assessment of choriocapillary blood flow changes in response to half-dose PDT in chronic central serous chorioretinopathy using OCTA

2020 ◽  
Author(s):  
Juejun Liu ◽  
Changzheng Chen ◽  
Lu Li ◽  
Yishuang Xu ◽  
Zuohuizi Yi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Central Serous Chorioretinopathy ◽  
Early Stage ◽  
Early Response ◽  
Chronic Central Serous Chorioretinopathy ◽  
Quantify Blood Flow ◽  
Gender And Age ◽  
Half Dose ◽  
Flow Changes

Abstract Background: To quantify blood flow changes in choriocapillaris (CC) of chronic central serous chorioretinopathy (CCSC) patients receiving half-dose photodynamic therapy (PDT) using optical coherence tomography angiography (OCTA).Methods: A total of 28 affected eyes and 24 unaffected eyes of 26 CCSC patients receiving half-dose PDT, and 40 eyes of 20 healthy gender- and age-matched subjects were retrospectively enrolled. The proportion of total areas of flow signal voids (FSV, %) in CC level of OCTA was assessed in both eyes of the CCSC patients at baseline and repeated in multiple sections at 1-week, 1-month, 3-month and 6-month intervals after PDT. In addition, CC patterns in response to PDT at early stage and their subsequent morphologic changes were qualitatively documented using OCTA. Results: For affected eyes, significant decrease in FSV was found at 6-m follow-up when compared with that at 1-m follow-up (p=0.036). When compared to normal control eyes, FSV in affected eyes was significantly higher at 1-m, 3-m and 6-m follow-up (p<0.05 for all), while FSV in unaffected eyes was significantly higher at baseline, 1-w, 1-m and 3-m follow-up (p<0.05 for all). Three CC patterns of early response to PDT were identified, including signs of recovery with more even flow signals, transient appearance of worse ischemia and secondary neovascularization within CC level.Conclusion: Abnormal CC flow attenuation remains in completely resolved eyes of CCSC patients treated with half-dose PDT.

scholarly journals Analysis of the vascular abnormalities of the patients with ankle joint mild osteoarthritis

2020 ◽  
Vol 24 (1) ◽  
pp. 26-37
Author(s):  
A. O. Mombekov ◽  
N. I. Karpovich ◽  
O. A. Dogotar ◽  
A. V. Dergunov ◽  
N. B. Zagorodnyi
Keyword(s):  
Blood Flow ◽  
Ankle Joint ◽  
Lower Leg ◽  
Control Group ◽  
Hemodynamic Parameters ◽  
Vascular Abnormalities ◽  
Vascular Factor ◽  
Secondary Injuries ◽  
Flow Changes

The vascular factor is one of the leading pathogenesis factors in the formation of ankle joint osteoarthritis. Dystrophic and sclerotic changes in the joint tissues develop as a result of blood flow decrease. These mechanisms understanding will allow to plan treatment and rehabilitation measures, as well as predict and prevent complications. The purpose of the work is to study hemodynamic parameters in the main lower leg arteries of the in patients in follow-up period of mild ankle joint osteoarthritis. Two groups of patients were examined. The first group - 82 patients with mild ankle joint osteoarthritis in the follow-up period (10 years) and the second group - control (healthy) group of 58 people without ankle joint osteoarthritis. Duplex scan of the main lower leg arteries was performed to all the patients. The state of arteries and hemodynamic parameters were evaluated. Excell and STATISTICA 10.0 programs were used for statistical data processing. In patients with follow-up of mild ankle joint osteoarthritis, the diameter of the arteries did not differ from the control group. In patients with mild ankle joint osteoarthritis the thickness of the Intima-media complex in the lower leg arteries and walls pulsation were significantly higher than those in patients of the control group (p <0.05). Analysis of hemodynamic parameters in patients with ankle joint osteoarthritis revealed an increase in the linear velocity of blood flow with a further tendency to normalization and even decrease in the follow-up compared with the control group. Signs of perfusion difficulty that accompanied the development of high blood pressure syndrome in the lower leg arteries were observed in 122 (67.0%) patients, and the signs of perfusion difficulty were bilateral in most of the cases (86.9%). Stenosis, deformation and arteries tortuosity were noted in 22% of patients with ankle joint osteoarthritis. Thus, mild ankle joint osteoarthritis is accompanied by blood flow changes in the form of inadequate perfusion and high-pressure syndrome in the lower leg arteries, which can cause secondary injuries and requires higher attention when selecting treatment and rehabilitation actions.

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