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  • 1.
    Ambarki, Khalid
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindqvist, Tomas
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Petterson, E
    Warntjes, JBM
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Evaluation of automatic measurement of the intracranial volume based on quantitative MR imaging2012In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 33, no 10, p. 1951-1956Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Brain size is commonly described in relation to ICV, whereby accurate assessment of this quantity is fundamental. Recently, an optimized MR sequence (QRAPMASTER) was developed for simultaneous quantification of T1, T2, and proton density. ICV can be measured automatically within minutes from QRAPMASTER outputs and a dedicated software, SyMRI. Automatic estimations of ICV were evaluated against the manual segmentation.

    MATERIALS AND METHODS: In 19 healthy subjects, manual segmentation of ICV was performed by 2 neuroradiologists (Obs1, Obs2) by using QBrain software and conventional T2-weighted images. The automatic segmentation from the QRAPMASTER output was performed by using SyMRI. Manual corrections of the automatic segmentation were performed (corrected-automatic) by Obs1 and Obs2, who were blinded from each other. Finally, the repeatability of the automatic method was evaluated in 6 additional healthy subjects, each having 6 repeated QRAPMASTER scans. The time required to measure ICV was recorded.

    RESULTS: No significant difference was found between reference and automatic (and corrected-automatic) ICV (P > .25). The mean difference between the reference and automatic measurement was -4.84 ± 19.57 mL (or 0.31 ± 1.35%). Mean differences between the reference and the corrected-automatic measurements were -0.47 ± 17.95 mL (-0.01 ± 1.24%) and -1.26 ± 17.68 mL (-0.06 ± 1.22%) for Obs1 and Obs2, respectively. The repeatability errors of the automatic and the corrected-automatic method were <1%. The automatic method required 1 minute 11 seconds (SD = 12 seconds) of processing. Adding manual corrections required another 1 minute 32 seconds (SD = 38 seconds).

    CONCLUSIONS: Automatic and corrected-automatic quantification of ICV showed good agreement with the reference method. SyMRI software provided a fast and reproducible measure of ICV.

  • 2.
    Ambarki, Khalid
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    MR imaging of brain volumes: evaluation of a fully automatic software2011In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 32, no 2, p. 408-412Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Automatic assessment of brain volumes is needed in researchand clinical practice. Manual tracing is still the criterionstandard but is time-consuming. It is important to validatethe automatic tools to avoid the problems of clinical studiesdrawing conclusions on the basis of brain volumes estimatedwith methodologic errors. The objective of this study was toevaluate a new commercially available fully automatic softwarefor MR imaging of brain volume assessment. Automatic and expertmanual brain volumes were compared.

    MATERIALS AND METHODS: MR imaging (3T, axial T2 and FLAIR) was performed in 41 healthyelderly volunteers (mean age, 70 ± 6 years) and 20 patientswith hydrocephalus (mean age, 73 ± 7 years). The softwareQBrain was used to manually and automatically measure the followingbrain volumes: ICV, BTV, VV, and WMHV. The manual method hasbeen previously validated and was used as the reference. Agreementbetween the manual and automatic methods was evaluated by usinglinear regression and Bland-Altman plots.

    RESULTS: There were significant differences between the automatic andmanual methods regarding all volumes. The mean differences wereICV = 49 ± 93 mL (mean ± 2SD, n = 61), BTV = 11± 70 mL, VV = –6 ± 10 mL, and WMHV = 2.4± 9 mL. The automatic calculations of brain volumes tookapproximately 2 minutes per investigation.

    CONCLUSIONS: The automatic tool is promising and provides rapid assessmentof brain volumes. However, the software needs improvement beforeit is incorporated into research or daily use. Manual segmentationremains the reference method.

  • 3.
    Ambarki, Khalid
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Zarrinkoob, Laleh
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Wirestam, R.
    Petr, J.
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Accuracy of Parenchymal Cerebral Blood Flow Measurements Using Pseudocontinuous Arterial Spin-Labeling in Healthy Volunteers2015In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 36, no 10, p. 1816-1821Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: The arterial spin-labeling method for CBF assessment is widely available, but its accuracy is not fully established. We investigated the accuracy of a whole-brain arterial spin-labeling technique for assessing the mean parenchymal CBF and the effect of aging in healthy volunteers. Phase-contrast MR imaging was used as the reference method. MATERIALS AND METHODS: Ninety-two healthy volunteers were included: 49 young (age range, 20-30 years) and 43 elderly (age range, 65-80 years). Arterial spin-labeling parenchymal CBF values were averaged over the whole brain to quantify the mean pCBF(ASL) value. Total. CBF was assessed with phase-contrast MR imaging as the sum of flows in the internal carotid and vertebral arteries, and subsequent division by brain volume returned the pCBF(PCMRI) value. Accuracy was considered as good as that of the reference method if the systematic difference was less than 5 mL/min/100 g of brain tissue and if the 95% confidence intervals were equal to or better than +/- 10 mL/min/100 g. RESULTS: pCBF(ASL) correlated to pCBF(PCMRI) (r = 0.73; P < .001). Significant differences were observed between the pCBF(ASL) and pCBF(PCMRI) values in the young (P = .001) and the elderly (P < .001) volunteers. The systematic differences (mean 2 standard deviations) were -4 +/- 14 mL/min/100 g in the young subjects and 6 +/- 12 mL/min/100 g in the elderly subjects. Young subjects showed higher values than the elderly subjects for pCBF(PCMRI) (young, 57 +/- 8 mL/min/100 g; elderly, 54 +/- 7 mL/min/100 g; P = .05) and pCBF(ASL) (young, 61 +/- 10 mL/min/100 g; elderly, 48 +/- 10 mL/min/100 g; P < .001). CONCLUSIONS: The limits of agreement were too wide for the arterial spin-labeling method to be considered satisfactorily accurate, whereas the systematic overestimation in the young subjects and underestimation in the elderly subjects were close to acceptable. The age-related decrease in parenchymal CBF was augmented in arterial spin-labeling compared with phase-contrast MR imaging.

  • 4.
    Johansson, Elias
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Fox, A. J.
    Carotid Near-Occlusion: A Comprehensive Review, Part 1 - Definition, Terminology, and Diagnosis2016In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 37, no 1, p. 2-10Article, review/survey (Refereed)
    Abstract [en]

    Carotid near-occlusion is distal ICA luminal collapse beyond a tight stenosis, where the distal lumen should not be used for calculating percentage stenosis. Near-occlusion with full ICA collapse is well-known, with a threadlike lumen. However, near-occlusion without collapse is often subtle and can be overlooked as a usual severe stenosis. More than 10 different terms have been used to describe near-occlusion, sometimes causing confusion. This systematic review presents what is known about carotid near-occlusion. In this first part, the foci are definition, terminology, and diagnosis.

  • 5.
    Johansson, Elias
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Fox, A. J.
    Carotid Near-Occlusion: A Comprehensive Review, Part 2 - Prognosis and Treatment, Pathophysiology, Confusions, and Areas for Improvement2016In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 37, no 2, p. 200-204Article, review/survey (Refereed)
    Abstract [en]

    Carotid near-occlusion is distal luminal collapse of the internal carotid artery beyond a tight stenosis. Part 2 of this systematic review focuses on prognosis and treatment and pathophysiology. Areas of confusion regarding terminology, diagnosis, and prognosis are also covered. SUMMARY: In Part 1 of this review, the definition, terminology, and diagnosis of carotid near-occlusion were presented. Carotid near-occlusions (all types) showed a lower risk of stroke than other severe stenoses. However, emerging evidence suggests that the near-occlusion prognosis with full collapse (higher risk) differs from that without full collapse (lower risk). This systematic review presents what is known about carotid near-occlusion. In this second part, the foci are prognosis and treatment, pathophysiology, the current confusion about near-occlusion, and areas in need of future improvement.

  • 6.
    Johansson, Elias
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Salzer, Jonatan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Interaction should guide management decisions2018In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 39, no 5, p. E57-E57Article in journal (Other academic)
  • 7. Lynoe, N.
    et al.
    Olsson, D.
    Eriksson, Anders
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Forensic Medicine.
    Is Delayed Speech Development a Long-Term Sequela of Birth-Related Subdural Hematoma?2019In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 40, no 2, p. E10-E10Article in journal (Refereed)
  • 8. Shanks, J.
    et al.
    Bloch, K. Markenroth
    Laurell, Katarina
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Cesarini, K. G.
    Fahlstroem, M.
    Larsson, E-M
    Virhammar, J.
    Aqueductal CSF Stroke Volume Is Increased in Patients with Idiopathic Normal Pressure Hydrocephalus and Decreases after Shunt Surgery2019In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 40, no 3, p. 453-459Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Increased CSF stroke volume through the cerebral aqueduct has been proposed as a possible indicator of positive surgical outcome in patients with idiopathic normal pressure hydrocephalus; however, consensus is lacking. In this prospective study, we aimed to compare CSF flow parameters in patients with idiopathic normal pressure hydrocephalus with those in healthy controls and change after shunt surgery and to investigate whether any parameter could predict surgical outcome.

    MATERIALS AND METHODS: Twenty-one patients with idiopathic normal pressure hydrocephalus and 21 age- and sex-matched healthy controls were prospectively included and examined clinically and with MR imaging of the brain. Eighteen patients were treated with shunt implantation and were re-examined clinically and with MR imaging the day before the operation and 3 months postoperatively. All MR imaging scans included a phase-contrast sequence.

    RESULTS: The median aqueductal CSF stroke volume was significantly larger in patients compared with healthy controls (103.5 μL; interquartile range, 69.8–142.8 μL) compared with 62.5 μL (interquartile range, 58.3–73.8 μL; P < .01) and was significantly reduced 3 months after shunt surgery from 94.8 μL (interquartile range, 81–241 μL) to 88 μL (interquartile range, 51.8–173.3 μL; P < .05). Net flow in the caudocranial direction (retrograde) was present in 11/21 patients and in 10/21 controls. Peak flow and net flow did not differ between patients and controls. There were no correlations between any CSF flow parameters and surgical outcomes.

    CONCLUSIONS: Aqueductal CSF stroke volume was increased in patients with idiopathic normal pressure hydrocephalus and decreased after shunt surgery, whereas retrograde aqueductal net flow did not seem to be specific for patients with idiopathic normal pressure hydrocephalus. On the basis of the results, the usefulness of CSF flow parameters to predict outcome after shunt surgery seem to be limited.

  • 9. Virhammar, J.
    et al.
    Laurell, K.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Ahlgren, A.
    Larsson, E.-M.
    Arterial spin-labeling perfusion MR imaging demonstrates regional CBF decrease in idiopathic normal pressure hydrocephalus2017In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 38, no 11, p. 2081-2088Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Regional cerebral blood flow has previously been studied in patients with idiopathic normal pressure hydrocephalus with imaging methods that require an intravenous contrast agent or expose the patient to ionizing radiation. The purpose of this study was to assess regional CBF in patients with idiopathic normal pressure hydrocephalus compared with healthy controls using the noninvasive quantitative arterial spin-labeling MR imaging technique. A secondary aim was to compare the correlation between symptom severity and CBF. MATERIALS AND METHODS: Differences in regional cerebral perfusion between patients with idiopathic normal pressure hydrocephalus and healthy controls were investigated with pseudocontinuous arterial spin-labeling perfusion MR imaging. Twenty-one consecutive patients with idiopathic normal pressure hydrocephalus and 21 age- and sex-matched randomly selected healthy controls from the population registry were prospectively included. The controls did not differ from patients with respect to selected vascular risk factors. Twelve different anatomic ROIs were manually drawn on coregistered FLAIR images. The Holm-Bonferroni correction was applied to statistical analyses. RESULTS: In patients with idiopathic normal pressure hydrocephalus, perfusion was reduced in the periventricular white matter (P < .001), lentiform nucleus (P < .001), and thalamus (P < .001) compared with controls. Cognitive function in patients correlated with CBF in the periventricular white matter (r = 0.60, P < .01), cerebellum (r = 0.63, P < .01), and pons (r = 0.71, P < .001). CONCLUSIONS: Using pseudocontinuous arterial spin-labeling, we could confirm findings of a reduced perfusion in the periventricular white matter, basal ganglia, and thalamus in patients with idiopathic normal pressure hydrocephalus previously observed with other imaging techniques.

  • 10. Virhammar, J.
    et al.
    Laurell, Katarina
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Cesarini, K. G.
    Larsson, E. -M
    Preoperative Prognostic Value of MRI Findings in 108 Patients with Idiopathic Normal Pressure Hydrocephalus2014In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 35, no 12, p. 2311-2318Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: MR imaging is used in the diagnostic evaluation of patients with idiopathic normal pressure hydrocephalus. The aim of this study was to describe the prevalence of several imaging features and their prognostic use in the selection of shunt candidates with idiopathic normal pressure hydrocephalus. MATERIALS AND METHODS: Preoperative MR imaging scans of the brain were retrospectively evaluated in 108 patients with idiopathic normal pressure hydrocephalus who had undergone a standardized, clinical evaluation before and 12 months after shunt surgery. The MR imaging features investigated were the Evans index, callosal angle, narrow sulci at the high convexity, dilation of the Sylvian fissure, diameters of the third ventricle and temporal horns, disproportionately enlarged subarachnoid space hydrocephalus, flow void through the aqueduct, focal bulging of the roof of the lateral ventricles, deep white matter hyperintensities, periventricular hyperintensities, and focal widening of sulci and aqueductal stenosis. RESULTS: In logistic regression models, with shunt outcome as a dependent variable, the ORs for the independent variables, callosal angle, disproportionately enlarged subarachnoid space hydrocephalus, and temporal horns, were significant (P < .05), both in univariate analyses and when adjusted for age, sex, and previous stroke. CONCLUSIONS: A small callosal angle, wide temporal horns, and occurrence of disproportionately enlarged subarachnoid space hydrocephalus are common in patients with idiopathic normal pressure hydrocephalus and were significant predictors of a positive shunt outcome. These noninvasive and easily assessed radiologic markers could aid in the selection of candidates for shunt surgery.

  • 11. Virhammar, J
    et al.
    Warntjes, M
    Laurell, Katarina
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Larsson, E-M
    Quantitative MRI for Rapid and User-Independent Monitoring of Intracranial CSF Volume in Hydrocephalus2016In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 37, no 5, p. 797-801Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Quantitative MR imaging allows segmentation of different tissue types and automatic calculation of intracranial volume, CSF volume, and brain parenchymal fraction. Brain parenchymal fraction is calculated as (intracranial volume - CSF volume) / intracranial volume. The purpose of this study was to evaluate whether the automatic calculation of intracranial CSF volume or brain parenchymal fraction could be used as an objective method to monitor volume changes in the ventricles.

    MATERIALS AND METHODS: A lumbar puncture with drainage of 40 mL of CSF was performed in 23 patients under evaluation for idiopathic normal pressure hydrocephalus. Quantitative MR imaging was performed twice within 1 hour before the lumbar puncture and was repeated 30 minutes, 4 hours, and 24 hours afterward. For each time point, the volume of the lateral ventricles was manually segmented and total intracranial CSF volume and brain parenchymal fraction were automatically calculated by using Synthetic MR postprocessing.

    RESULTS: At 30 minutes after the lumbar puncture, the volume of the lateral ventricles decreased by 5.6 ± 1.9 mL (P < .0001) and the total intracranial CSF volume decreased by 11.3 ± 5.6 mL (P < .001), while brain parenchymal fraction increased by 0.78% ± 0.41% (P < .001). Differences were significant for manual segmentation and brain parenchymal fraction even at 4 hours and 24 hours after the lumbar tap. There was a significant association using a linear mixed model between change in manually segmented ventricular volume and change in brain parenchymal fraction and total CSF volume, (P < .0001).

    CONCLUSIONS: Brain parenchymal fraction is provided rapidly and fully automatically with Synthetic MRI and can be used to monitor ventricular volume changes. The method may be useful for objective clinical monitoring of hydrocephalus.

  • 12.
    Vågberg, Mattias
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Lindqvist, T.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Ambarki, Khalid
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Warntjes, J. B. M.
    Sundström, Peter
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Svenningsson, Anders
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Automated Determination of Brain Parenchymal Fraction in Multiple Sclerosis2013In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 34, no 3, p. 498-504Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Brain atrophy is a manifestation of tissue damage in MS. Reduction in brain parenchymal fraction is an accepted marker of brain atrophy. In this study, the approach of synthetic tissue mapping was applied, in which brain parenchymal fraction was automatically calculated based on absolute quantification of the tissue relaxation rates R1 and R2 and the proton attenuation. MATERIALS AND METHODS: The BPF values of 99 patients with MS and 35 control subjects were determined by using SyMap and tested in relationship to clinical variables. A subset of 5 patients with MS and 5 control subjects were also analyzed with a manual segmentation technique as a reference. Reproducibility of SyMap was assessed in a separate group of 6 healthy subjects, each scanned 6 consecutive times. RESULTS: Patients with MS had significantly lower BPF (0.852 0.0041, mean +/- SE) compared with control subjects (0.890 +/- 0.0040). Significant linear relationships between BPF and age, disease duration, and Expanded Disability Status Scale scores were observed (P < .001). A strong correlation existed between SyMap and the reference method (r = 0.96; P < .001) with no significant difference in mean BPF. Coefficient of variation of repeated SyMap BPF measurements was 0.45%. Scan time was <6 minutes, and postprocessing time was <2 minutes. CONCLUSIONS: SyMap is a valid and reproducible method for determining BPF in MS within a clinically acceptable scan time and postprocessing time. Results are highly congruent with those described using other methods and show high agreement with the manual reference method.

  • 13.
    Wåhlin, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Ambarki, Khalid
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Alperin, Noam
    Department of Radiology, University of Miami, Miami, Florida.
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Assessment of craniospinal pressure-volume indices2010In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 31, no 9, p. 1645-1650Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: The PVI(CC) of the craniospinal compartment defines the shape of the pressure-volume curve and determines the damping of cyclic arterial pulsations. Despite no reports of direct measurements of the PVI(CC) among healthy elderly, it is believed that a change away from adequate accommodation of cardiac-related pulsations may be a pathophysiologic mechanism seen in neurodegenerative disorders such as Alzheimer disease and idiopathic normal pressure hydrocephalus. In this study, blood and CSF flow measurements are combined with lumbar CSF infusion measurements to assess the craniospinal PVI(CC) and its distribution of cranial and spinal compartments in healthy elderly.

    MATERIALS AND METHODS: Thirty-seven healthy elderly were included (60-82 years of age). The cyclic arterial volume change and the resulting shift of CSF to the spinal compartment were quantified by PC-MR imaging. In addition, each subject underwent a lumbar CSF infusion test in which the magnitude of cardiac-related pulsations in intracranial pressure was quantified. Finally, the PVI was calculated by using a mathematic model.

    RESULTS: After excluding 2 extreme values, the craniospinal PVI(CC) was calculated to a mean of 9.8 ± 2.7 mL and the estimated average 95% confidence interval of individual measurements was ± 9%. The average intracranial and spinal contributions to the overall compliance were 65% and 35% respectively (n = 35).

    CONCLUSIONS: Combining lumbar CSF infusion and PC-MR imaging proved feasible and robust for assessment of the craniospinal PVI(CC). This study produced normative values and showed that the major compensatory contribution was located intracranially.

  • 14.
    Wåhlin, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Ambarki, Khalid
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Wieben, O
    Johnson, KM
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Measuring pulsatile flow in cerebral arteries using 4D phase-contrast magnetic resonance imaging2013In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 34, no 9, p. 1740-1745Article in journal (Other academic)
    Abstract [en]

    BACKGROUND AND PURPOSE: 4D PCMRI can be used to quantify pulsatile hemodynamics in multiple cerebral arteries. The aim of this study was to compare 4D PCMRI and 2D PCMRI for assessments of pulsatile hemodynamics in major cerebral arteries. MATERIALS AND METHODS: We scanned the internal carotid artery, the anterior cerebral artery, the basilar artery, and the middle cerebral artery in 10 subjects with a single 4D and multiple 2D PCMRI acquisitions by use of a 3T system and a 32-channel head coil. We assessed the agreement regarding net flow and the volume of arterial pulsatility (V) for all vessels. RESULTS: 2D and 4D PCMRI produced highly correlated results, with r = 0.86 and r = 0.95 for V and net flow, respectively (n = 69 vessels). These values increased to r = 0.93 and r = 0.97, respectively, during investigation of a subset of measurements with <5% variation in heart rate between the 4D and 2D acquisition (n = 31 vessels). Significant differences were found for ICA and MCA net flow (P = .004 and P < .001, respectively) and MCA V (P = .006). However, these differences were attenuated and no longer significant when the subset with stable heart rate (n = 31 vessels) was analyzed. CONCLUSIONS: 4D PCMRI provides a powerful methodology to measure pulsatility of the larger cerebral arteries from a single acquisition. A large part of differences between measurements was attributed to physiologic variations. The results were consistent with 2D PCMRI.

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