title: Evaluation of cerebral vascular reserve by single photon emission tomography in children with congenital hydrocephalus.
abstract: OBJECTIVE
  Single photon emission tomography scan (SPECT) is used to measure cerebral blood flow (CBF) and also cerebral vascular reserve (CVR) after intravenous acetazolamide (ACZ) challenge. This prospective study was designed to test the utility of CVR in congenital hydrocephalus (CHC).
  
  
  METHODS
  Patients (n = 21, mean age 6.2 m) with CHC underwent a baseline ultrasonography (US), retinal fundus examination (RF), neurological score (NS), and SPECT to evaluate CVR after intravenous ACZ. Monthly US, RF, NS, CBF, and CVR were evaluated.
  
  
  RESULTS
  Ten patients showed good CVR and also had stable NS and RF despite mild to moderate ventriculomegaly and were followed up on conservative treatment. None of these patients in a mean follow-up period of 9.8 months showed deterioration. Eleven patients, who had poor CVR initially, were also treated conservatively. Over a period of 4 months, 8 patients showed a fall in CVR to < 30 % of baseline and a fall in NS despite RF and US remaining the same and hence were operated. Five of these operated cases showed an improvement in CVR and NS over a mean follow-up period of 4 months and the remaining 3 patients failed to show improvement in CVR and NS.
  
  
  CONCLUSIONS
  In CHC, CVR measured by ACZ challenge test is a sensitive parameter as alterations in CVR occur prior to changes in other conventional parameters such as ventriculomegaly and RF. Patients with normal CVR at presentation are unlikely to deteriorate and can safely be managed conservatively. Patients who show a deterioration in CVR should be considered for prompt surgery.
authors.affiliation: The Department of Paediatric Surgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: A
authors.initials: A
authors.lastname: Pratap
authors.forename: M
authors.initials: M
authors.lastname: Srinivas
authors.forename: P
authors.initials: P
authors.lastname: Hentok
authors.forename: C S
authors.initials: CS
authors.lastname: Bal
authors.forename: V
authors.initials: V
authors.lastname: Bhatnagar
mesh_terms: D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000503:physiopathology*; D007223:Infant; D008297:Male; D009460:Neurologic Examination; D011379:Prognosis; D015899:Tomography, Emission-Computed, Single-Photon