Radionuclide cisternography: imaging and study of the cerebrospinal fluid circulation

Abstract

English: English: Radionuclide cisternography performed in 200 selected patients with neurological disease has proved to be a simple and relatively safe procedure, v,rithminimal disturbing side effects, which can provide useful information about cerebrospinal fluid (eSF) flow and dynamics. Following the subarachnoid or ventricular injection of an appropiate radiopharmaceutical, the tracer flows with the eSF and demonstrates the pathways of circulation under normal and abnormal conditions with virtually no disruption of the existing eSF physiology. The eventual distribution of the tracer is complex. The range of normal varies from rapid ascent with early absorption of the radiopharmaceutical to slower ascent and absorption, frequently with laterilization of flow to one or other side intracranially and occasionally with transient ventricular reflux. In pathological states the cisternographic picture varies ac= cation (or lack of it) of the ventricles with the subarachnoid cording to the underlying disease. It may lack the ability to establish the precise anatomical features available from air encephalography. However ventricular dilatation, the communispace, and the delay or lack of absorption are only satisfactorily demonstrated by radionuclide cisternography. Repeated examinations may be readily performed to show progression of the disease or the results of surgical treatment. The abnormal flow pattern in patients with normal pressure hydrocephalus proved to be the most important criterion in their selection for extracranial neurosurgical eSF shunting. When properly selected, these patients often respond to surgical treatment. The routine use of radionuclide cisternography in the examination of patients with suspected presenile dementia and compensated hydrocephalus results in a low yield of operable patients. When operation is contraindicated conservative management of the patient is then instituted and unnecessary surgical intervention avoided. Radionuclide cisternography gained wide acceptance in the evaluation of shunt patency. The test is fast and safe in the presence of extracranial diversionary eSF shunts. The rapid flow into the cerebral ventricles and the fast disappearance of the radioactive tracer, as well as the relative size of the ventricular system, are valuable indexes for the determination of patency and efficaccy of the shunt. Another important use of radionuclide cisternography is the investigation of eSF leaks and eSF spinal flow obstruction. It may demonstrate the existence and site of eSF leakage or block and offer valuable assistance to the neurosurgeon. Radionuclide cisternographic images are usually interpreted subjectively on the basis of abnormal regional and temporal concentrations of radiopharmaceuticals in the eSF space. The evaluation of images can be improved by the use of quantitative computerized digital scanning, increasing the sensitivity and value of the measurements. The further extension of these studies involving abnormalities of cerebrospinal fluid dynamics would seem worthwhile, and the value of the methods described in this thesis and their limitations, remain a potential and challenging field for further exploration.

Afrikaans: Radionuklied-sisternografie is by 200 geselekteerde pasiënte met neurologiese aandoenings uitgevoer. Dit is gevind om 'n eenvoudige en veilige ondersoekprosedure te wees - 'n tegniek met minimale komplikasies, wat nuttige inligting betreffende serebrospinale vloeistof (S.S.V.)-vloei en ~dinamika verskaf. Na die subaragnoiedale of ventrikulêre inspuiting van 'n geskikte radiofarmaseutiese materiaal, volg die merker die S.S.V.-vloeibaan. Sonder versteuring van S.S.V.-fisiologie kan die vloeipatroon by normale of abnormale toestande dan bestudeer word. Die uiteindelike verspreiding van die radioaktiewe merker word bepaal deur komplekse faktore sekondêr tot die patologiese en patofisiologiese aard van die besondere siektetoestand. Die normale patroon van isotoopvloei na spinale inspuiting wissel van persoon tot persoon. Daar mag vinnige styging van merker met verspreiding oor die serebrale hemisfere, en snelle absorpsie wees, of relatief vertraagde vloei en absorpsie - selfs met 'n mate van intrakraniale isotoop-lateralisering. Soms word kortstondige ventrikulêre refluksvulling selfs opgemerk. Die skerpomlynde anatomiese afbeelding van S.S.V.-ruimtes by lugenkefalografie verkry, ontbreek kwalitatief by radionukliedsisternografie. Andersynds word ventrikulêre uitsetting met refluks, S.S.V.-verbindings tussen die ventrikels en die subaragnoiedale ruimte as geheel, asook vertraagde of gebrekkige S.S.V.-absorpsie slegs met sisternografie bevredigend gedemonstreer. Herhaalde ondersoeke kan voorts uitgevoer word om die verloop van 'n siektetoestand of die gevolg van chirurgiese behandeling te beoordeel. Die abnormale S.S.V.-vloeipatroon kenmerkend van normale drukhidrokefalus, was een van die nuttigste kliniese toepassings van sisternografie - veral by die sorgvuldige selektering van pasiënte geskik vir ekstrakraniale neuro-chirurgiese aftakkingsprosedures. Hierdie terapeutiese ingreep lei dan dikwels tot omkering van die siekteproses en verbetering van simptome. Alhoewel die roetine gebruik van radionuklied-sisternografie by die ondersoek van vermoedelike preseniele demensie en gekompenseerde hidrokefalus gelei het tot 'n lae opbrengs van pasiënte geskik vir vermelde operasie, is 'n negatiewe bevinding tog nuttige bevestiging dat konserwatiewe terapie ingestel en chirurgiese ingrepe vermy moet word. Radionuklied-sisternografie is ook van groot waarde by die doeltreffendheidsbeoordeling van aftakkingsprosedures. So 'n ondersoek kan vinnig en veilig uitgevoer word deur isotoop in die ventrikel te plaas. Die opruimingsnelheid vanuit die serebrale ventrikels, asook die relatiewe grootte van die ventrikulêre sisteem is waardevolle aanduidings van die doeltreffendheid van die ekstrakraniale aftakking. Ander waardevolle gebruike van radionuklied-sisternografie sluit in die ondersoek van S.S.V.-lekkasie en obstruksie van spinale S.S.V.-vloei. Dit het unieke waarde by die presiese anatomiese lokalisering van areas van S.S.V.-lekkasie. Die nut van sisternografie, op die basis van subjektiewe beoordeling van abnormale vloeipatrone of regionale konsentrasie van radio-farmaseutiese stowwe in die S.S.V.-ruimte, kan aangevul word deur gebruik te maak van kwantitatiewe gerekenariseerde digitale flikkergrafie. Die verdere uitbreiding van hierdie studies waardeur abnormaliteite van S.S.V.-vloei atrournaties beoordeel word, bied vele toekomsmoontlikhede op die gebied van kliniese gebruik en navorsing.