Wie beeinflusst die Angulation des Halses die MR-basierte Quantifizierung des jugular venösen Blutflusses?

Zielsetzung: Die Quantifizierung des jugular venösen Flusses rückte zuletzt zunehmend in den Fokus der aktuellen Forschung, besonders seit ein fraglicher Zusammenhang zwischen chronischer cerebrovenöser Insuffizienz und der Multiplen Sklerose postuliert wurde. Unser Ziel war es, den Einfluss der Angulation des Halses in Rückenlage auf die jugular venöse Drainage zu untersuchen. Material und Methodik: 16 Probanden (7 männlich 27y ± 3,4; 9 weiblich 25y ± 2,3) wurden mittels Puls getriggerter Phasenkontrast Sequenzen auf Höhe C2 in einem 3T MRT (Magnetom Verio, Siemens Healthcare) untersucht. Der Winkel zwischen C2 und C7 wurde in T1-gewichteten Sequenzen gemessen. Die Messungen wurden zuerst in einer neutralen Kopfposition und nachfolgend in Reklination und Inklination in randomisierter Reihenfolge durchgeführt. Der Blutfluss durch die inneren Jugularvenen (IJVF) wurde mittels eines Pulsatilitäts basierten Algorithmus quantifiziert. Zur statistischen Auswertung wurden gepaarte t-Tests verwendet. Ergebnisse: Es zeigten sich hochsignifikante Unterschiede für den IJVF für Flexion (p < 0,05; Range 134–742ml/min; Mittelwert 483±200ml/min) und Reklination (p < 0,02; Range 110–672ml/min; MW 479±151ml/min) im Vergleich zur neutralen Kopfposition (Range 177–773ml/min; MW 569±167ml/min). Zwischen Flexion und Reklination zeigte sich kein signifikanter Unterschied (p=0,92). Der C2-C7 Winkel in der neutralen Stellung reichte von -2 bis 50° (MW 20°±15). Die interindividuelle Differenz zwischen Inklination und Reklination reichte von 24 bis 62° (MW 44°±9,5). Schlussfolgerungen: Der jugular venöse Blutfluss wird signifikant durch die Angulation des Halses beeinflusst. Es gibt eine hohe interindividuelle Variation der Angulation des Halses in der „neutralen“ Kopfposition. Dies sollte bei der Interpretation von Studien zum cerebralvenösen Blutfluss berücksichtigt werden, z.B. des venösen Flusses bei MS. E-Mail: [email protected]

Total cerebral blood flow during childhood and adolescence as assessed with phase-contrast imaging

Aims: To investigate the total cerebral blood flow (TCBF) non-invasively based on MRI across physiological development and to collect normative values from childhood to adolescence. Methods: 55 neurological healthy subjects between 3 and 18 years (28 male, 27 female) were investigated on a 3T MRI. Axial cine-phase contrast sequences were performed perpendicular to the neck vessels to quantify arterial inflow through the left and right carotid (LCA, RCA) and left and right vertebral artery (LVA and RVA). Data were analyzed using linear regression models. Results: Total cerebral blood flow defined as the sum of flow through the four cervical arteries (mean 1073 +/- 203ml/min) significantly decreased with increasing age (p0.05). Conclusion: Total cerebral blood flow can be non-invasively assessed with phase-contrast-imaging. TCBF is age-dependent and decreases with increasing age whereas gender does not have an impact on the TCBF in our study. These age-related changes need to be taken into consideration when pediatric patients are evaluated with phase contrast MRI

Decreased Craniocervical CSF Flow in Patients with Normal Pressure Hydrocephalus: A Pilot Study

Normal pressure hydrocephalus is characterized by systolic peaks of raised intracranial pressure, possibly due to a reduced compliance of the spinal CSF spaces. This concept of a reduced spinal CSF buffer function may be reflected by a low cervical CSF outflow from the cranium. The aim of this study was to investigate craniospinal CSF flow rates by phase-contrast MR imaging in patients with normal pressure hydrocephalus. A total of 42 participants were included in this prospective study, consisting of 3 study groups: 1) 10 patients with normal pressure hydrocephalus (mean age, 74 [SD, 6] years, with proved normal pressure hydrocephalus according to current scientific criteria); 2) eighteen age-matched healthy controls (mean age, 71 [SD, 5] years); and 3) fourteen young healthy controls (mean age, 21 [SD, 2] years, for investigation of age-related effects). Axial phase-contrast MR imaging was performed, and the maximal systolic CSF and total arterial blood flow rates were measured at the level of the upper second cervical vertebra and compared among all study groups (2-sample unpaired test). The maximal systolic CSF flow rate was significantly decreased in patients with normal pressure hydrocephalus compared with age-matched and young healthy controls (53 [SD,  40] mL/m; 329 [SD,  175] mL/m; 472 [SD, 194] mL/m; each < .01), whereas there were no significant differences with regard to maximal systolic arterial blood flow (1160 [SD, 404] mL/m; 1470 [SD,  381] mL/m; 1400 [SD, 254] mL/m; each > .05). The reduced maximal systolic craniospinal CSF flow rate in patients with normal pressure hydrocephalus may be reflective of a reduced compliance of the spinal CSF spaces and an ineffective spinal CSF buffer function. Systolic craniospinal CSF flow rates are an easily obtainable MR imaging-based measure that may support the diagnosis of normal pressure hydrocephalus

MR-tomographic assessment of hemodynamic and hydrodynamic characteristics in migraine patients

Purpose: The etiology of migraine headaches remains to be elucidated. We aimed to assess hemodynamic and hydrodynamic characteristic in migraine patients compared to healthy controls. Methods and Materials: We examined 14 patients (age range 21–50 years) with clinically proven recurring migraine headaches and 12 healthy controls (age range 20–39 years) on a 3T MR with velocity-encoding phase contrast scans. Arterial inflow, venous outflow, and craniospinal CSF stroke volumes were measured and the intracranial pressure (MRICP) was derived from the ratio of the systolic intracranial volume change and pulse pressure gradient. Results: Patients with Migraine had a significantly lower intracranial pressure when compared to the controls (7.4 vs.10.0; p<0.05). In addition CSF stroke volume tended to be lower in patients with migraine (0.55 vs. 0.72; p=0.58). Hemodynamic parameters did not show significant differences between the groups. Conclusion: Intracranial pressure measured by MR was shown to be lower in migraine patients when compared to healthy controls which may be a potential parameter in explaining the disease etiology

Comparison of normalized total cerebral blood flow between adolescents and adults assessed by MR imaging

Purpose: During the course of adulthood and ageing, the total cerebral blood flow (tCBF) is known to decrease about 4% per decade. However, it is unclear whether this same rate applies to adolescents. Methods: We examined 6 adolescents (age range 14 to 16 years) and 15 young adults (age range 20 to 30 years) without neurological disorders on a 3T MR with velocity-encoding phase contrast scans. Cine-phase contrast techniques were used to measure the flow through the carotid and vertebral arteries. TCBF was obtained by summation of the mean blood flow. To account for the influence of the brain tissue volumes, values normalized the total amount of gray and white matter were computed [ml/min/100mg]. Results: Mean TCBF values and normalized CBF values were significantly higher in adolescents compared to young adults (mean TCBF 88 vs. 77ml/min, p<; mean normalized TCBF XX vs. XX ml/min/100mg, p<) Conclusion: TCBF reduces at a higher rate between adolescents and young adults than in the course of later adultshood

Automated MR-based lung volume segmentation in population-based whole-body MR imaging: Correlation with clinical characteristics, pulmonary function testing and obstructive lung disease.

ObjectivesWhole-body MR imaging is increasingly utilised; although for lung dedicated sequences are often not included, the chest is typically imaged. Our objective was to determine the clinical utility of lung volumes derived from non-dedicated MRI sequences in the population-based KORA-FF4 cohort study.Methods400 subjects (56.4 9.2 years, 57.6% males) underwent whole-body MRI including a coronal T1-DIXON-VIBE sequence in inspiration breath-hold, originally acquired for fat quantification. Based on MRI, lung volumes were derived using an automated framework and related to common predictors, pulmonary function tests (PFT; spirometry and pulmonary gas exchange, n = 214) and obstructive lung disease.ResultsMRI-based lung volume was 4.0 1.1 L, which was 64.8 14.9% of predicted total lung capacity (TLC) and 124.4 27.9% of functional residual capacity. In multivariate analysis, it was positively associated with age, male, current smoking and height. Among PFT indices, MRI-based lung volume correlated best with TLC, alveolar volume and residual volume (RV; r = 0.57 each), while it was negatively correlated to FEV1/FVC (r = 0.36) and transfer factor for carbon monoxide (r = 0.16). Combining the strongest PFT parameters, RV and FEV1/FVC remained independently and incrementally associated with MRI-based lung volume ( = 0.50, p = 0.04 and = - 0.02, p = 0.02, respectively) explaining 32% of the variability. For the identification of subjects with obstructive lung disease, height-indexed MRI-based lung volume yielded an AUC of 0.673-0.654.Conclusion Lung volume derived from non-dedicated whole-body MRI is independently associated with RV and FEV1/FVC. Furthermore, its moderate accuracy for obstructive lung disease indicates that it may be a promising tool to assess pulmonary health in whole-body imaging when PFT is not available.Key Points Although whole-body MRI often does not include dedicated lung sequences, lung volume can be automatically derived using dedicated segmentation algorithms Lung volume derived from whole-body MRI correlates with typical predictors and risk factors of respiratory function including smoking and represents about 65% of total lung capacity and 125% of the functional residual capacity Lung volume derived from whole-body MRI is independently associated with residual volume and the ratio of forced expiratory volume in 1 s to forced vital capacity and may allow detection of obstructive lung diseas