Alteration of cerebral perfusion in patients with idiopathic normal pressure hydrocephalus measured by 3D perfusion weighted magnetic resonance imaging.
OBJECTIVE
It is controversial whether alteration of cerebral perfusion plays an important role in the pathophysiology of patients with idiopathic normal pressure hydrocephalus (NPH) and can help to predict the outcome after shunt surgery.


METHODS
28 patients with suspected NPH were examined clinically (Homburg Hydrocephalus Scale, walking test, incontinence protocol) and by 3D dynamic susceptibility based perfusion weighted magnetic resonance imaging (PWI-MRI) before and after cerebrospinal fluid release (spinal tap test, STT). The perfusion parameters (negative integral (NI), time of arrival (T0), time to peak (TTP), mean transit time, and the difference TTP-T0 were analysed.


RESULTS
Three different groups of patients were identified preoperatively: In group 1 seven patients showed an increase in the cerebral perfusion and a clinical improvement after STT. The second group (9 patients) also revealed an increase of the cerebral perfusion, but no significant alteration of the clinical assessment could be found. In the third group neither the cerebral perfusion nor the clinical assessment changed. 14 of the 16 patients (group 1 and 2) were examined three months after shunt placement. 11 patients showed a good or excellent result, 2 patients revealed a fair assessment, and only 1 patient had transiently improved. No patient was downgraded after shunting. In the patient group 1 and 2 the NI increased significantly (effect size: 34%), whereas in group 3 no significant alteration of NI was observed.


CONCLUSIONS
PWI-MRI improves the prediction of outcome after shunt placement in patients with NPH and can offer new insights into the pathophysiology.
Walter
Christof
C
Dept. of Radiology and Neuroradiology, Krankenhaus der Barmherzigen Brüder, Nordallee 1, 54292 Trier, Germany. ch.walter@bk-trier.de
Hertel
F
F
Naumann
E
E
Mörsdorf
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001931:Brain Mapping; D002557:Cerebrospinal Fluid Shunts / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D010477:Perfusion / Q000379:methods*; D011300:Preoperative Care; D012680:Sensitivity and Specificity; D013129:Spinal Puncture / Q000379:methods; D013997:Time Factors