diapositiva 1 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 PHASE CONTRAST MR AS NON- INVASIVE TOOL IN THE DIAGNOSIS OF BENIGN INTRACRANIAL HYPERTENSION L. Nocetti (1), A. Mantovani (2), S. Vallone (3), T. Costi (1), P. Carpeggiani (3), G. Pinna (2) (1) AOU Policlinico, Modena, Health Physics Unit; (2) S. Agostino Hospital, Modena, Neurosurgery Unit; (3) S. Agostino Hospital, Modena, Neuroradiology Unit.

diapositiva 2 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 The gold standard: direct measurement (invasive) Lumbar puncture During a procedure for VP- shunt insertion

diapositiva 3 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 A proposed alternative way (1) : MR protocol (non- invasive) Background Intracranial Pressure Volume relationship (1,2) [1] N Alperin et al.. Radiology, 12: , [2] HW Ryder, FF Espey, FD Kimbell, and et al. J Lab Clin Med, 41: , [3] A Marmarou et al.. J Neurosurg, 43: , Pressure and Elastance Pressure and Compliance

diapositiva 4 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 A proposed alternative way: MR protocol (non- invasive) Intracranial Volume Change Monro Killie doctrine: -Blood, CSF and cerebral tissue are assumed not to change in volume when pressure is applied; -Intracranial Volume does not change. However.... Small changes have been observed and measured during the cardiac cycle(1) [1] Ueno et al. Development of a non invasive technique for the measurement of intracranial pressure Biol Sci Space 12: , 1998 Therefore... Intracranial volume can (slightly) change during the cardiac cycle.

diapositiva 5 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 A proposed alternative way: MR protocol (non- invasive) Variation in Pressure Navier-Stokes Equation (linearized) [1] Loth F, Yardimci MA, Alperin N: Hydrodynamic modeling of cerebrospinal fluid motion within the spinal cavity. J Biomech Eng 123:71–79, 2001 Inertial term Viscous term Pressure Variation CSF density coeff CSF viscosity coeff It requires Newtonian fluid : where can we find C2 level as shown in (1)!

diapositiva 6 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 The study 55 patients (10 male, 45 female, mean age 37±18) with suspected IIH underwent MR examination. In 12 female patients direct recording of CSF pressure was also obtained ( 8 lumbar punctures and 4 VP shunts).  Hydrodynamic parameters (CSF velocity flow, CSF intensity flow,..) as well as biomechanical –functional parameters (intracranial Volume Change, Intracranial Compliance and Elastance) were measured with MR acquisition protocol.  Correlations were searched between invasive pressure measurements and the MR derived parameters

diapositiva 7 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 The MR acquisition protocol – phase contrast sequence Acquisition Parameters: Phase contrast sequence cardiac triggered, Matr: 256x256 FOV 140mm thk 6mm TR/TE: 12.7/8.4ms; Pixel BW: 127Hz; Cardiac phases: 32; VENC: 70cm/s (blood), 9cm/s (CSF) VA ICA IJV Blood sequence CSF sequence

diapositiva 8 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 Results ANALYSIS: Pressure & PearsonP value Elastance0,6532 0,021 ICC-0,5563 0,060 ICVC-0,3300 0,295 C2 max vel0,2521 0,429 C2 max flow-0,0804 0,804 C2 volume-0,2590 0,416 C3 max vel0,0724 0,823 C3 max flow-0,1732 0,590 C3 volume-0,3174 0,315

diapositiva 9 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 Conclusions (1) In this study a statistically significant relationship between Pressure measurement and Elastance MR derived has been found; Based on these findings, this MR protocol is a promising tool for a non-invasive diagnosis in patients with benign intracranial hypertension as well in other suspected CSF flow derangement pathologies (Chiari malformation, syringomyelia, hydrocephalus, …).

diapositiva 10 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 Conclusions (2) Larger case study group and further clarifications are needed : Better characterization of the venous outflow from the brain (e.g. venogram, SWI ); More complex model that takes into account individual differences (e.g. parenchimal volume brain)

diapositiva 11 XIX SYMPOSIUM NEURORADIOLOGICUM – Bologna 4-9 October 2010 THANKS!