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

Nichtinvasive Bestimmung des intrakraniellen Drucks MR-basierte Untersuchung bei Kindern mit Hydrozephalus

Der intrakranielle Druck („intracranial pressure“ – ICP) ist ein entscheidender Parameter bei der Diagnostik, Therapie und Verlaufsbeurteilung von Patienten mit Hydrozephalus.Derzeit gibt es keine radiologische Standardmethode, um den intrakraniellen Druck quantitativ zu bestimmen. Methoden zur invasiven und nichtinvasiven Einschätzung des ICP werden diskutiert und die Anwendung eines MR-basierten Verfahrens (MR-ICP) bei Patienten mit Hydrozephalus vorgestellt.Der MR-ICP wird nichtinvasiv aus der intrakraniellen Volumenänderung, die während eines Herzzyklus entsteht, und dem kraniozervikalen Druckgradienten des Liquorflusses berechnet.Fünfzehn Patienten mit Hydrozephalus, davon 6 (2,5–14,61 Jahre alt; Mittelwert 7,4 Jahre) mit Verdacht auf erhöhten ICP, und 9 ohne klinische Zeichen eines erhöhten ICP (2,1–15,9 Jahre alt; Mittelwert 9,8 Jahre) wurden an einem 3-T-MRT mittels Phasenkontrastangiographie untersucht. Der mediane MR-ICP der Patienten mit akuter Symptomatik lag bei 24,5 mmHg (25%-Perzentile 20,4 mmHg; 75%-Perzentile 44,5 mmHg). Der mediane MR-ICP der Patienten ohne akute Symptomatik war 9,8 mmHg (25%-Perzentile 8,6 mmHg; 75%-Perzentile 11,4 mmHg). Der Gruppenunterschied war signifikant (p <0,001; Mann-Whitney-U-Test).Der MR-ICP ist eine vielversprechende, nichtinvasive Methode zur Einschätzung des ICP.Weitere Studien zur Evaluation der Anwendung bei verschiedenen klinischen Fragestellungen sind notwendig.The intracranial pressure (ICP) is a crucially important parameter for diagnostic and therapeutic decision-making in patients with hydrocephalus.So far there is no standard method to non-invasively assess the ICP. Various approaches to obtain the ICP semi-invasively or non-invasively are discussed and the clinical application of a magnetic resonance imaging (MRI)-based method to estimate ICP (MR-ICP) is demonstrated in a group of pediatric patients with hydrocephalus.Arterial inflow, venous drainage and craniospinal cerebrospinal fluid (CSF) flow were quantified using phase-contrast imaging to derive the MR-ICP.A total of 15 patients with hydrocephalus (n=9 treated with shunt placement or ventriculostomy) underwent MRI on a 3 T scanner applying retrospectively-gated cine phase contrast sequences. Of the patients six had clinical symptoms indicating increased ICP (age 2.5–14.61 years, mean 7.4 years) and nine patients had no clinical signs of elevated ICP (age 2.1–15.9 years; mean 9.8 years; all treated with shunt or ventriculostomy). Median MR-ICP in symptomatic patients was 24.5 mmHg (25th percentile 20.4 mmHg; 75th percentile 44.6 mmHg). Median MR-ICP in patients without acute signs of increased ICP was 9.8 mmHg (25th percentile 8.6 mmHg; 75th percentile 11.4 mmHg). Group differences were significant (p < 0.001; Mann-Whitney U-test).The MR-ICP technique is a promising non-invasive tool for estimating ICP.Further studies in larger patient cohorts are warranted to investigate its application in children with hydrocephalus

Secondary cerebrovenous outflow in relation to duration of disease in patients with multiple sclerosis

Aims: Previous studies show an increased secondary venous outflow in patients with MS. The aim of this study was to determine whether the degree of drainage through secondary venous channels is related to the duration of the disease. Methods: We examined 40 patients at the age of 12 to 63 years (mean 31.7 years, 1st quartile: 20.5 years, 3rd quartile: 38.5 years) with multiple sclerosis. Mean value of the duration of disease was 7.1 years (1st quartile: 2.0 years, 3rd quartile: 11.0 years). To visualize primary veins (left and right internal jugular vein – LIJV, RIJV) and secondary veins (right and left vertebral vein – VV, epidural vein – EV, deep cervical vein – DCV) a 2D time-of-flight MR-venography (MRV) of the upper cervical regions was performed. MRVs were visually analyzed and secondary venous outflow was graded: 1– no; 2– minimal; 3– mild secondary venous outflow; 4– pronounced secondary venous outflow in one of the three pathways (VV, EV or DCV); 5– secondary venous outflow in two of the three pathways and 6– secondary venous outflow in all three pathways. The statistical evaluation was implemented by means of multiple regression analysis. Results: 1 patient was classified in grade 1, 4 patients were classified in grade 2, 6 patients were classified in grade 3, 13 patients were classified in grade 4, 16 patients were classified in grade 5, no patient was classified in grade 6. The degree of secondary venous drainage is significantly and positively related to duration of disease (p-value=0.0331). Conclusion: In the examined group patients with a longer existing MS disease have more venous outflow in secondary veins than patients with a shorter duration of disease. We draw the conclusion that secondary venous drainage indicates duration of disease in patients with MS