Value of quantitative MRI biomarkers (Evans' index, aqueductal flow rate, and apparent diffusion coefficient) in idiopathic normal pressure hydrocephalus

2009 ◽  
Vol 30 (4) ◽  
pp. 708-715 ◽  
Author(s):  
Samuel E.S. Ng ◽  
Angela M.S. Low ◽  
Kok Kee Tang ◽  
Y.H. Chan ◽  
Robert K. Kwok
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Flow Rate ◽  
Normal Pressure Hydrocephalus ◽  
Normal Pressure ◽  
Idiopathic Normal Pressure Hydrocephalus ◽  
Quantitative Mri ◽  
Apparent Diffusion ◽  
Evans Index

Increase in callosal angle and decrease in ventricular volume after shunt surgery in patients with idiopathic normal pressure hydrocephalus

2018 ◽  
Vol 130 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Johan Virhammar ◽  
Katarina Laurell ◽  
Kristina Giuliana Cesarini ◽  
Elna-Marie Larsson
Keyword(s):  
Normal Pressure Hydrocephalus ◽  
Normal Pressure ◽  
Visual Assessment ◽  
Ventricular Volume ◽  
Relative Difference ◽  
Idiopathic Normal Pressure Hydrocephalus ◽  
Quantitative Mri ◽  
Shunt Surgery ◽  
Shunt Valve ◽  
Evans Index

OBJECTIVEPostoperative decrease in ventricle size is usually not detectable either by visual assessment or by measuring the Evans index in patients with idiopathic normal pressure hydrocephalus (iNPH). The aim of the present study was to investigate whether the angle between the lateral ventricles (the callosal angle [CA]) increases and ventricular volume decreases after shunt surgery in patients with iNPH.METHODSMagnetic resonance imaging of the brain was performed before and 3 months after shunt surgery in 18 patients with iNPH. The CA and Evans index were measured on T1-weighted 3D MR images, and ventricular volume contralateral to the shunt valve was measured with quantitative MRI.RESULTSThe CA was larger postoperatively (mean 78°, 95% CI 69°–87°) than preoperatively (mean 67°, 95% CI 60°–73°; p < 0.001). The volume of the lateral ventricle contralateral to the shunt valve decreased from 73 ml (95% CI 66–80 ml) preoperatively to 63 ml (95% CI 54–72 ml) postoperatively (p < 0.001). The Evans index was 0.365 (95% CI 0.35–0.38) preoperatively and 0.358 (95% CI 0.34–0.38) postoperatively (p < 0.05). Postoperative change of CA showed a negative correlation with change of ventricular volume (r = −0.76, p < 0.01).CONCLUSIONSIn this sample of patients with iNPH, the CA increased and ventricular volume decreased after shunt surgery. The relative difference was most pronounced for the CA, indicating that this accessible, noninvasive radiological marker should be evaluated further as an indirect method to determine shunt function in patients with iNPH.

scholarly journals Phase-contrast magnetic resonance imaging reveals net retrograde aqueductal flow in idiopathic normal pressure hydrocephalus

2016 ◽  
Vol 124 (6) ◽  
pp. 1850-1857 ◽  
Author(s):  
Geir Ringstad ◽  
Kyrre Eeg Emblem ◽  
Per Kristian Eide
Keyword(s):  
Flow Rate ◽  
Normal Pressure Hydrocephalus ◽  
Phase Contrast ◽  
Normal Pressure ◽  
Idiopathic Normal Pressure Hydrocephalus ◽  
Conservative Group ◽  
Shunt Placement ◽  
Before And After ◽  
Shunt Group ◽  
Antegrade Flow

OBJECT The objective of this study was to assess the net aqueductal stroke volume (ASV) and CSF aqueductal flow rate derived from phase-contrast MRI (PC-MRI) in patients with probable idiopathic normal pressure hydrocephalus (iNPH) before and after ventriculoperitoneal shunt surgery, and to compare observations with intracranial pressure (ICP) scores. METHODS PC-MRI at the level of the sylvian aqueduct was undertaken in patients undergoing assessment for probable iNPH. Aqueductal flow in the craniocaudal direction was defined as positive, or antegrade flow, and net ASV was calculated by subtracting retrograde from antegrade aqueductal flow. Aqueductal flow rate per minute was calculated by multiplying net ASV by heart rate. During the same hospital admission, clinical examination was performed using NPH score and overnight continuous ICP monitoring. Twelve patients were followed prospectively 12 months after shunt placement with clinical assessment and a second PC-MRI. The study also included 2 healthy controls. RESULTS Among 21 patients examined for iNPH, 17 (81%) received a shunt (shunt group), and 4 were treated conservatively (conservative group). Among the patients with shunts, a clinical improvement was observed in 16 (94%) of the 17. Net ASV was negative in 16 (76%) of 21 patients before shunt placement and in 5 (42%) of 12 patients after shunt placement, and increased from a median of −5 μl (range −175 to 27 μl) to a median of 1 μl (range −61 to 30 μl; p = 0.04). Among the 12 patients with PC-MRI after shunt placement, 11 were shunt responders, and in 9 of these 11 either a reduced magnitude of retrograde aqueductal flow, or a complete reversal from retrograde to antegrade flow, occurred. Net ASV was significantly lower in the shunt group than in the conservative group (p = 0.01). The aqueductal flow rate increased from −0.56 ml/min (range −12.78 to 0.58 ml/min) to 0.06 ml/min (range −4.51 to 1.93 ml/min; p = 0.04) after shunt placement. CONCLUSIONS In this cohort of patients with iNPH, retrograde net aqueductal flow was observed in 16 (76%) of 21 patients. It was reversed toward the antegrade direction after shunt placement either by magnitude or completely in 9 (75%) of 12 patients examined using PC-MRI both before and after shunt placement (p = 0.04); 11 of the 12 were shunt responders. The study results question previously established concepts with respect to both CSF circulation pathways and CSF formation rate.

scholarly journals Diagnostic Performance of Glymphatic System Evaluation Using Diffusion Tensor Imaging in Idiopathic Normal Pressure Hydrocephalus and Mimickers

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Hajime Yokota ◽  
Arvind Vijayasarathi ◽  
Milos Cekic ◽  
Yoko Hirata ◽  
Michael Linetsky ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Normal Pressure Hydrocephalus ◽  
Diagnostic Performance ◽  
Roc Analysis ◽  
Diffusion Tensor ◽  
Normal Pressure ◽  
Idiopathic Normal Pressure Hydrocephalus ◽  
Glymphatic System ◽  
Evans Index ◽  
Diffusion Tensor Imaging Dti

Purpose. To investigate the pathological change of the glymphatic system in idiopathic normal pressure hydrocephalus (iNPH) using diffusion tensor imaging (DTI) analysis. Materials and Methods. 24 right-handed patients were referred to our hydrocephalus clinic for assessment of ventriculomegaly and gait impairment. 12 of 24 were diagnosed as pseudo-iNPH (piNPH) based on assessment by a neurologist. Diffusivity maps in the direction of the x-axis (right-to-left) (Dx), y-axis (anterior-to-posterior) (Dy), and z-axis (inferior-to-superior) (Dz) were computed. The diffusion map was coregistered to International Consortium for Brain Mapping (ICBM) DTI-81 atlas. The analysis along the perivascular space (ALPS) index was defined as mean (Dxpro, Dypro)/mean (Dypro, Dzasc), where Dxpro and Dxasc are Dx values in the projection and association fiber areas, respectively. Evans index and callosal angle were also assessed on each case. Results. ALPS indexes of the control, piNPH, and iNPH cases were 1.18 ± 0.08, 1.08 ± 0.03, and 0.94 ± 0.06, respectively, and there were significant differences among the groups (control vs. piNPH, P = 0.003; control vs. iNPH P < 0.001; piNPH vs. iNPH, P < 0.001). Area under curve (AUC) was 0.92, 1.00, and 1.00 on control vs. piNPH, control vs. iNPH, and piNPH vs. iNPH on ROC analysis. Between piNPH and NPH, ALPS index has higher diagnostic performance than Evans index and callosal angle (AUC = 1.00 vs. 0.84, P = 0.028; AUC = 1.00 vs. 0.74, P = 0.016). Conclusion. Atlas-based ALPS index using the DTI method differentiated among iNPH, piNPH, and controls clearly.

scholarly journals Parkinsonian Symptomatology May Correlate with CT Findings before and after Shunting in Idiopathic Normal Pressure Hydrocephalus

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Mitsuaki Ishii ◽  
Toshio Kawamata ◽  
Ichiro Akiguchi ◽  
Hideo Yagi ◽  
Yuko Watanabe ◽  
...  
Keyword(s):  
Normal Pressure Hydrocephalus ◽  
Postural Stability ◽  
Rating Scale ◽  
Normal Pressure ◽  
Idiopathic Normal Pressure Hydrocephalus ◽  
Stepwise Multiple Regression ◽  
Ct Findings ◽  
Before And After ◽  
Evans Index ◽  
Disease Rating

We aimed to investigate the characteristics of Parkinsonian features assessed by the unified Parkinson's disease rating scale (UPDRS) and determine their correlations with the computed tomography (CT) findings in patients with idiopathic normal pressure hydrocephalus (iNPH). The total score and the scores for arising from chair, gait, postural stability, and body hypokinesia in the motor examination section of UPDRS were significantly improved after shunt operations. Stepwise multiple regression analysis revealed that postural stability was the determinant of the gait domain score of the iNPH grading scale. The canonical correlation analysis between the CT findings and the shunt-responsive Parkinsonian features indicated that Evans index rather than midbrain diameters had a large influence on the postural stability. Thus, the pathophysiology of postural instability as a cardinal feature of gait disturbance may be associated with impaired frontal projections close to the frontal horns of the lateral ventricles in the iNPH patients.

WP1-10 Prevalence of normal pressure hydrocephalus in falls clinic patients

2019 ◽  
Vol 90 (3) ◽  
pp. e4.2-e4 ◽  
Author(s):  
S Sennik ◽  
C Craven ◽  
L D’Antona ◽  
H Asif ◽  
W Dawes ◽  
...  
Keyword(s):  
General Hospital ◽  
Normal Pressure Hydrocephalus ◽  
Normal Population ◽  
District General Hospital ◽  
Normal Pressure ◽  
Idiopathic Normal Pressure Hydrocephalus ◽  
List Type ◽  
Ventricular Enlargement ◽  
Evans Index ◽  
One Year

ObjectivesPatients with idiopathic Normal Pressure Hydrocephalus (iNPH) present with Hakim Adams triad and radiological findings suggestive of iNPH. We compare the presence of clinical and radiological signs of iNPH present in patients presenting to falls clinic at a District General Hospital with the general population.DesignRetrospective analysis of patients referred to falls clinic (January 2017 to December 2017) and interpretation of CT or MRI head imaging with Evans index.SubjectsFalls clinic patients presenting to a District General Hospital outpatient clinic.MethodsRetrospective cohort of patients admitted to a single District General Hospital with falls and recent CT or MRI head. An Evans Index above 0.35 was used as an indicator of hydrocephalic ventricular enlargement.Results371 patients were seen in one year. 216 had previous CT or MRI head. 6.75% of all patients seen in falls clinic (11.6% who have had brain imaging) have hydrocephalic ventricular enlargement. This is compared to 4.5% in a study of patients aged 70 and over in a normal population.1ConclusionsPatients seen in Falls clinic have an increased probability of having radiological signs consistent with idiopathic normal pressure hydrocephalus.ReferenceJaraj D, Marlow T, Jensen C, Skoog I, Wikkelso C. Prevalence of idiopathic normal-pressure hydrocephalus. Neurology2014April 22;82(16):1449–1454.

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