OBJECTIVE: To investigate the severity of blood steal and the hemodynamic profiles in patients with subclavian artery stenosis combined with vertebral artery stenosis. METHODS: A retrospective analysis was performed of transcranial Doppler (TCD) data from patients with subclavian artery stenosis (SAS) and concomitant unilateral/bilateral vertebral artery stenosis (VAS, >50%) or occlusion in our institution between February, 2014 and July, 2018.Thirty-seven patients with SAS combined with VAS (SAS+VAS) were reviewed for types of blood steal, peak systolic velocities of blood flow in affected subclavian artery and the contralateral vertebral artery, and the findings of hyperemia testing.These data were also reviewed for 39 SAS patients without VAS (control group) for comparison of blood steal and hemodynamic profiles. RESULTS: In SAS+VAS group, 5 patients showed no blood steal; blood steal in stage Ⅰ was found in 22 patients, stage Ⅱ in 7, and stage Ⅲ in 3, as compared to the numbers of 17, 12 and 10 in the control group, respectively (H=9.431, =0.002).The peak systolic velocity of the contralateral vertebral artery was 43.91±17.43 cm/s in SAS+VAS group, significantly lower than that in the control group (53.56±17.45 cm/s; = 629.5, =0.006).Hyperemia testing showed a significant difference in the negative rate between SAS+VAS group and the control group[35.1%(13/37) 7.7%(3/39);=8.603, =0.003). CONCLUSIONS SAS combined with VAS may lead to reduced compensatory blood flow in the contralateral vertebral artery to lessen the severity of subclavian steal syndrome.
Hemodynamics ; Humans ; Regional Blood Flow ; physiology ; Retrospective Studies ; Subclavian Steal Syndrome ; complications ; physiopathology ; Vertebral Artery ; physiopathology ; Vertebrobasilar Insufficiency ; complications ; physiopathology

No abstract available.
Aged ; Diagnosis, Differential ; Female ; Fluorescein Angiography ; Fundus Oculi ; Humans ; *Intraocular Pressure ; Regional Blood Flow/*physiology ; Retina/*diagnostic imaging ; Retinal Hemorrhage/*diagnosis/physiopathology ; Retinal Vein Occlusion/*diagnosis

PURPOSE: To evaluate choroidal blood flow changes in eyes with high myopia according to the pulsatile components of ocular blood flow analysis. METHODS: A total of 104 subjects (52 males and 52 females) were included in this study. One eye of each participant was randomly selected and assigned to one of four refractive groups, designated as, hyperopes (n = 20; refractive error, > or =+1.00 diopter [D]), emmetropes (n = 28; refractive error, +/-0.75 D), lower myopes (n = 33; refractive error, -1.00 to -4.75 D), and high myopes (n = 23; refractive error, < or =-5.00 D). Components of pulse amplitude (OBFa), pulse volume (OBFv), pulse rate (OBFr), and pulsatile ocular blood flow (POBF) were analyzed using a blood flow analyzer. Intraocular pressure and axial length were measured. RESULTS: Pulsatile components of OBFa, OBFv, and POBF showed positive correlations with refractive error and showed negative correlations with axial length (r = 0.729, r = 0.772, r = 0.781, respectively, all p < 0.001; r = -0.727, r = -0.762, r = -0.771, respectively, all p < 0.001). The correlations of refractive error and axial length with OBFr were irrelevant (r = -0.157, p = 0.113; r = 0.123, p = 0.213). High myopes showed significantly lower OBFa, OBFv, and POBF than the other groups (all p < 0.001). CONCLUSIONS: Axial length changes in high myopes potentially influence choroidal blood flow, assuming the changes are caused by narrowing of the choroidal vessel diameter and increasing rigidity of the choroidal vessel wall. These finding explains the influence of axial length on OBFa, OBFv, and POBF, but not on OBFr. Thus, changes in axial length and the possible influence of these changes on the physical properties of choroidal vessels is the mechanism believed to be responsible for putting high myopes at risk for ocular vascular diseases.
Adult ; *Axial Length, Eye ; Choroid/*blood supply ; Female ; Humans ; Male ; Myopia/diagnosis/*physiopathology ; Regional Blood Flow/*physiology ; Young Adult

PURPOSE: Despite technical simplicity and the low cost of brachial-ankle pulse wave velocity (BA-PWV), its use has been hampered by a lack of data supporting its usefulness and reliability. The aim of this study was to evaluate the usefulness of BA-PWV to measure aortic stiffness in comparison to using cardiovascular magnetic resonance (CMR). MATERIALS AND METHODS: A total of 124 participants without cardiovascular risk factors volunteered for this study. BA-PWV was measured using a vascular testing device. On the same day, using CMR, cross-sectional areas for distensibility and average blood flow were measured at four aortic levels: the ascending, upper thoracic descending, lower thoracic descending, and abdominal aorta. RESULTS: Compared to PWV measured by CMR, BA-PWV values were significantly higher and the differences therein were similar in all age groups (all p<0.001). There was a significant correlation between BA-PWV and PWV by CMR (r=0.697, p<0.001). Both BA-PWV and PWV by CMR were significantly and positively associated with age (r=0.652 and 0.724, p<0.001). The reciprocal of aortic distensibility also demonstrated a statistically significant positive correlation with BA-PWV (r=0.583 to 0.673, all p<0.001). CONCLUSION: BA-PWV was well correlated with central aortic PWV and distensibility, as measured by CMR, regardless of age and sex.
Adult ; Ankle Brachial Index/*methods ; Ankle Joint ; Aorta/anatomy & histology/*physiology ; *Blood Flow Velocity ; Cardiovascular Diseases ; Female ; Heart/physiopathology ; Humans ; *Magnetic Resonance Imaging, Cine ; Male ; Pulse Wave Analysis/*methods ; Regional Blood Flow ; Reproducibility of Results ; Risk Factors ; *Vascular Stiffness

Computational fluid dynamics (CFD) technology has the potential to simulate normal or pathologic aortic blood flow changes of mechanical properties and flow field, thereby helping researchers understand and reveal the occurrence, development and prognosis of aortic disease. In aortic diseases research, the initial conditions of CFD numerical simulation has experienced a developed process from idealization (forward engineering), rigid vessel wall, uniform cross-sections, laminar flow and stable blood flow towards personalization (reverse engineering), elastic vessel wall (fluid-solid coupling technique), cone-shaped diminishing cross-sections, turbulent flow, pulsatile blood flow. In this review, the research status, the technical superiority and application prospect of CFD technology were discussed with examples in following three major application areas: (1) dynamics characteristic and mechanical properties in normal thoracic aorta; (2) occurrence, advance and disruptive risk predicting in thoracic aortic aneurysm; (3) therapeutic effect and aneurysmal dilatation simulation in thoracic aortic dissection. For the future, the CFD technology may profoundly put an influence on the awareness to aortic diseases and treatment strategies.
Aorta ; pathology ; physiology ; Aortic Aneurysm, Thoracic ; physiopathology ; Computer Simulation ; Dilatation ; Hemodynamics ; Humans ; Pulsatile Flow ; Regional Blood Flow

OBJECTIVETo study the characteristics of blood flow in common hepatic tumors by 256-slice spiral CT whole-liver perfusion imaging.

METHODSSeventy-one patients with hepatic tumors were examined retrospectively by 256-slice spiral CT whole-liver perfusion. Among them, twenty-seven cases were of primary hepatic cancer, twenty-four cases of hepatic hemangioma, and twenty cases of hepatic metastases.Regions of interest (ROIs) were placed in the tumor parenchyma (Area A), peritumoral hepatic parenchyma (Area B), and normal hepatic parenchyma (Area C), respectively. The time density curves (TDC) were drawn, and perfusion parameters including hepatic arterial perfusion(HAP), portal venous perfusion(PVP), total liver perfusion(TLP) and hepatic erfusion index(HPI) were obtained. The values of ROIs were measured, and the perfusion parameters in the areas A, B, C of different hepatic tumors were statistically analyzed.

RESULTSThe values of HAP, PVP, HPI in the tumor parenchyma of primary hepatic carcinoma were (20.00 ± 11.41)ml · min(-1) · 100 ml(-1,) (32.31 ± 21.06)ml · min(-1) · 100 ml(-1,) (52.31 ± 30.55)ml · min(-1) · 100 ml(-1,) and (39.67 ± 11.19)%, showing significant difference as compared with those in peritumoral hepatic parenchyma and in normal hepatic parenchyma(P<0.05). The values of HAP, TLP, and HPI in the tumor parenchyma of hepatic hemangioma were (40.39 ± 29.23)ml · min(-1) · 100 ml(-1,) (132.72 ± 132.65) ml · min(-1) · 100 ml(-1,) and (35.51 ± 15.12)%, were significantly different as compared with those in the peritumoral hepatic parenchyma and in normal hepatic parenchyma(P<0.05). The values of HAP, PVP, HPI in the tumor parenchyma of hepatic metastases were (17.43 ± 12.27)ml · min(-1) · 100 ml(-1,) (36.19 ± 34.99) ml · min(-1) · 100 ml(-1,) and (37.86 ± 14.49)%, significantly different as compared normal hepatic parenchyma (P<0.05). The HAP, PVP, and TLP of tumor tissue and the PVP and HPI of peritumoral tissue in different hepatic tumors were statistically significantly different (P<0.05).

CONCLUSIONSThe multi-slice spiral CT whole-liver perfusion has certain value in the diagnosis of common hepatic tumors. Perfusion parameters in different areas of common hepatic tumors have their own hemodynamic characteristics.

Carcinoma, Hepatocellular ; blood supply ; diagnostic imaging ; Hemangioma ; blood supply ; diagnostic imaging ; Hepatic Artery ; diagnostic imaging ; physiology ; Humans ; Liver ; blood supply ; Liver Neoplasms ; blood supply ; diagnostic imaging ; secondary ; Perfusion Imaging ; Portal Vein ; diagnostic imaging ; physiology ; Regional Blood Flow ; Retrospective Studies ; Tomography, Spiral Computed

Adenosine was identified as a regulator of skeletal muscle blood flow almost 50 years ago. It was first proposed that increased use of ATP during muscle contractions led to net ATP breakdown, and its breakdown product, adenosine, diffused through the interstitial space to the blood stream to be washed away. En-route to its removal, adenosine was suggested to relax the vascular smooth muscle, thereby increasing the blood flow and oxygen supply to the contracting muscle. This mechanism has been researched quite intensively over the years, yet there are still many aspects that remain unclear. It has been confirmed that adenosine does, indeed, relax vascular smooth muscle and contribute to exercise hyperaemia, but the discovery that adenosine was formed extracellularly has shifted the research focus onto its precursor, ATP. ATP is released from many tissues, and produces many effects, including both vasodilation and vasoconstriction, as well as modulation of the neural mechanisms for skeletal muscle blood flow control. This review summarizes the current state of knowledge on the contributions of adenosine and ATP to the skeletal muscle vasodilation that accompanies contractile activity.
Adenosine ; physiology ; Adenosine Triphosphate ; physiology ; Exercise ; physiology ; Hemodynamics ; Humans ; Muscle Contraction ; Muscle, Skeletal ; blood supply ; Muscle, Smooth, Vascular ; physiology ; Regional Blood Flow ; physiology ; Vasoconstriction ; Vasodilation

This pictorial review provides the principles of extracorporeal membrane oxygenation (ECMO) support and associated CT imaging features with emphasis on the hemodynamic changes and possible imaging pitfalls encountered. It is important that radiologists in ECMO centers apply well-designed imaging protocols and familiarize themselves with post-contrast CT imaging findings in patients on ECMO.
Adult ; Aorta, Thoracic/physiopathology/radiography ; Contrast Media/administration & dosage/pharmacokinetics ; Extracorporeal Membrane Oxygenation/classification/*methods ; Female ; Heart-Assist Devices ; Hemodynamics/*physiology ; Humans ; Intra-Aortic Balloon Pumping/instrumentation ; Male ; Middle Aged ; *Multidetector Computed Tomography ; Regional Blood Flow/physiology ; Retrospective Studies ; Ventricular Dysfunction, Left/physiopathology/radiography

OBJECTIVE: The purpose of this study was to differentiate true progression from pseudoprogression of glioblastomas treated with concurrent chemoradiotherapy (CCRT) with temozolomide (TMZ) by using histogram analysis of apparent diffusion coefficient (ADC) and normalized cerebral blood volume (nCBV) maps. MATERIALS AND METHODS: Twenty patients with histopathologically proven glioblastoma who had received CCRT with TMZ underwent perfusion-weighted imaging and diffusion-weighted imaging (b = 0, 1000 sec/mm2). The corresponding nCBV and ADC maps for the newly visible, entirely enhancing lesions were calculated after the completion of CCRT with TMZ. Two observers independently measured the histogram parameters of the nCBV and ADC maps. The histogram parameters between the true progression group (n = 10) and the pseudoprogression group (n = 10) were compared by use of an unpaired Student's t test and subsequent multivariable stepwise logistic regression analysis to determine the best predictors for the differential diagnosis between the two groups. Receiver operating characteristic analysis was employed to determine the best cutoff values for the histogram parameters that proved to be significant predictors for differentiating true progression from pseudoprogression. Intraclass correlation coefficient was used to determine the level of inter-observer reliability for the histogram parameters. RESULTS: The 5th percentile value (C5) of the cumulative ADC histograms was a significant predictor for the differential diagnosis between true progression and pseudoprogression (p = 0.044 for observer 1; p = 0.011 for observer 2). Optimal cutoff values of 892 x 10-6 mm2/sec for observer 1 and 907 x 10-6 mm2/sec for observer 2 could help differentiate between the two groups with a sensitivity of 90% and 80%, respectively, a specificity of 90% and 80%, respectively, and an area under the curve of 0.880 and 0.840, respectively. There was no other significant differentiating parameter on the nCBV histograms. Inter-observer reliability was excellent or good for all histogram parameters (intraclass correlation coefficient range: 0.70-0.99). CONCLUSION: The C5 of the cumulative ADC histogram can be a promising parameter for the differentiation of true progression from pseudoprogression of newly visible, entirely enhancing lesions after CCRT with TMZ for glioblastomas.
Adult ; Aged ; Brain Neoplasms/*pathology/physiopathology/therapy ; Cerebrovascular Circulation/*physiology ; Combined Modality Therapy ; Diagnosis, Differential ; Diffusion Magnetic Resonance Imaging/*methods ; Disease Progression ; Female ; Glioblastoma/*pathology/physiopathology/therapy ; Humans ; Male ; Middle Aged ; Prognosis ; ROC Curve ; *Regional Blood Flow ; Reproducibility of Results ; Retrospective Studies

PURPOSE: To evaluate orbital blood flow velocities and optic nerve diameter with Doppler and gray-scale sonography in patients with acute unilateral optic neuritis (ON). METHODS: Orbital Doppler and gray-scale sonography was performed in 46 eyes of 23 patients aged 19- to 47-years with acute unilateral ON. ON was diagnosed by an ophthalmologist on the basis of clinical presentation, presence of decreased visual acuity and assessment of visual evoked potentials. The peak systolic velocity (PSV) and end-diastolic velocity (EDV), as well as the resistance index (RI) and pulsatile index (PI) of the ophthalmic artery (OA), central retinal artery (CRA), posterior ciliary arteries (PCAs) and optic nerve diameter were measured in both eyes. We compared results from affected and unaffected eyes using the paired t-test. The area under the receiver operating characteristic (ROC) curves was used to assess the diagnosis of ON based on measured blood flow parameters of the OA, CRA and PCAs and optic nerve diameter. RESULTS: The mean (standard deviation) optic nerve diameter in eyes with ON was 4.1 (0.8) mm, which was significantly larger than the 3.0 (0.4) mm diameter measured in unaffected control eyes (p < 0.001). There were no differences in average PSV, EDV, RI, or PI of the OA and CRA between affected and unaffected eyes (p > 0.05). The mean RI in the PCAs was slightly lower in the eyes with ON than in the contralateral eyes (0.60 vs. 0.64, p < 0.05). The area under the ROC curves indicated that optic nerve diameter was the best parameter for the diagnosis of ON. CONCLUSIONS: Optic nerve diameter was related to ON, but orbital blood flow parameters were not.
Adult ; Humans ; Middle Aged ; Ophthalmic Artery/*physiology/*ultrasonography ; Optic Nerve/*blood supply/*ultrasonography ; Optic Neuritis/*physiopathology/*ultrasonography ; Orbit/blood supply/ultrasonography ; Pulsatile Flow/physiology ; Regional Blood Flow/physiology ; Ultrasonography, Doppler, Color ; Vascular Resistance/physiology ; Young Adult