I.J.M.S. July,!989
An Evaluation of Cranial CT Scanning in Clinical Psychiatry *H. Colohan, *E. O'Callaghan, *C Larkin and +J. L. WaddiIlgton. *Cluain Mhuire Family Centre, NewlOwnpark Avenue, Blackrock, Co. Dublin, and +Department of Clinical Pharmacology, Royal College of Surgeons in Ireland, St. Stephen's Green, Duglin 2.
Summary From 6,300 psychiatric admissions over a 37 month period, all 54 patient referrals for CT were identified and their charts reviewed. CT influenced diagnosis, management or prognosis in 11.7 percent of patients scanned. There was poor correlation between organicity on CT scan and findings on physical examination, laboratory testing, EEG and psychological testing. The mental state examination was the single significant correlate of CT abnormality. We suggest that the use of a formalised mental state examination such as the Mini Mental State, in addition to the usual clinical assessment of mental state, may improve the accuracy of prediction of abnormality on CT scan. The introduction of X-ray computed tomography (Cn is recognised to be one of the most important innovations in the recent history of clinical medicine. In neurology the value of a noninvasive technique for examining the intracranial contents was quickly real: ised in the areas of diagnosis, particularly in the detection of vascular accidents and tumours!. CT has also attained a significant place in psychiatry. In research studies, it has provided important information on schizophrenia2 , alcoholism 3 ,4 and chronic organic reactions s.6 • The place of CT in clinical psychiatry is less clear. As its availability has increased, such scans are being requested with increasing frequency in psychiatric patients. Cranial CT is a highly sensitive diagnostic procedure which, when used unselectively, may result in the discovery of incidental findings. Until recently, a function of the psychiatrist in relation to diagnosis was to first seek to distinguish symptoms produced by organic pathology from those produced by functional illness. However, recent research suggests that this Address for Correspondence. Dr. E. O'Callaghan, Cluan Mhuire Family Centre, Newtownpark Avenue, Blackrock. Co. Dublin, Ireland.
dichotomy is not as clear as was formerly supposed. For example, studies on patients hospitalised for psychiatric reasons have pointed to a high incidence of neurological soft signs?, cognitive impairment8 ,9. EEG abnormalities!O and alterations in brain morphology, particularly cerebral ventricular enlargementll , in those who had a primary diagnosis of functional psychotic illness. This study was prompted by the fact that, to date, there has been no evaluation of the impact of CT in relation to psychiatry in this country. In other countries, at least preliminary information is available in this regard, and because of its utility in psychiatry some investigators have tried to identify the best clinical predictors ofCT abnormality.
Method With the assistance of the computerised records of the Research and Resource Centre of the St. John of God Psychiatric Services, Dublin, we traced 54 instances of patients undergoing CT from 6,300 psychiatric admissions to St. John of God Hospital, Stillorgan, Co. Dublin, between July 1st, 1984 and July 31st, 1987. To ensure completeness, we examined ward diaries and interviewed individual doctors. All patients had been' referred for CT for clinical reasons, and scans had been requested whilst patients were still in hospital. Information from case notes was available on all 53 patients (one patient had two CT scans). Information pertaining to mental status examination, physical examination, medication and other laboratory, neuropsychological and electroencephalographic reports was reviewed in all cases. From records of each patient's mental state (recorded under the following headings: general attitud~ and behaviour, stream of talk, mood, intellectual functions, and content of thought), organic features were deemed to be present if the patient exhibited disorientation in time, place or person, memory 178
impairment which was inexplicable on the basis of attentional deficit, aphasia, apraxia or agnosia, or hallucinations other than auditory hallucinations. From a conventional neurological examination, organic features were deemed to be present if any abnormality was evident in the pyramidal, extrapyramidal, sensory or cerebellar systems, or if apparent cranial nerve dysfunction not consistent with end-organ disease was observed. Laboratory tests were designated as normal or abnormal on the basis of normative data. Psychological assessments were taken as indicative of organic brain disease on the basis of scores on the Weschler Adult Intelligence Test, the Bender Gestalt, and Memory for Designs tests. The EEG was classified as normal, containing definite, specific abnormalities or containing non-specific abnormalities according to conventional criteria applied by the relevant consultant. CT was performed and reviewed at one of three different University Radiological Centres. They were classifie;d as normal, abnormal or inconclusive on the basis of the routine reports of the relevant consultant neuroradiologist. Diagnoses reported below were made by independent consultant psychiatrists according to the International Classification of Diseases (Ninth Revision). Results were analysed using the Fisher Exact Probability Test (2 tailed), and the Mann-Whitney "U" Test (2 - tailed).
Results 54 scans were performed. 25 patients were male and 28 female (one patient was scanned twice). The mean age of patients scanned was 51.3 years± 18.2. (S.D.) (range 14 to 79 years). The length of stay of patients who were referred for CT scan varied from 5 to 1299 days. The mean length of stay was greatly affected by the presence of one patient who had been in hospital continuously for 1299 days. This patient's scan was a six-monthly "re-
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Cranial CT scanning 179 TABLE I
INmAL DIAGNOSIS I. Other organic psychotic condition 2. 3. 4. 5. 6. 7. 8. 9. 10. I I. 12. 13. 14. 15. 16. 17. 18. 19. 20. 2 I. 22. 23. 24. 25. 26. 27. 28. 29. 30. 3 I. 32. 33. 34. 35. 36. 37. 38. 39. 40. 4 I. 42. 43. 44. 45. 46. 47. 48. 49. 50. 5 I. 52. 53. 54.
Affective psychosis Dementia Pre-Senile Dementia Senile Dementia + acute confusional state Schizophrenic psychosis - paranoid type Schizophrenic psychosis - paranoid type Brain tumour Transient organic psychotic condition Non psychotic mental disorder following organic brain damage Neurotic depression Transient organic psychotic condition Arteriosclerotic dementia Alcohol dependence syndrome Head injury & alcohol dependence syndrome Neurotic depression Transient organic psychotic depression Organic psychotic condition Epilepsy and mental retardation Senile Dementia Transient organic psychotic condition. Residual schizophrenia Schizophrenia psychosis - paranoid type Schizophrenic psychosis - paranoid type Schizophrenic psychosis - hebephrenic tyupe Transient organic psychotic condition. Residual schizophrenia Affective psychosis Hysterical personality disorder Brain tumour Pre-Senile Dementia Paranoid state Arteriosclerotic dementia Other organic psychotic condition (Neurosyphillis) Schizophrenic psychosis - schizoaffective type Acute schizophrenic episode Organic psychotic condition. Suspected brain tumour Affective psychosis Neurotic depression Korsakov's psychosis Transient organic psychotic condition Affective disorder Transient organic psychotic condition Senile Dementia Anxiety state Schizophrenic psychosis - paranoid type Dementia Organic psychotic condition Schizophrenic psychosis - paranoid type. Post hypophysectomy review Pre-Senile Dementia Paranoid st? ~ Acute schizophrenic episode Anxiety state Affective disorder Schizophrenic psychosis - paranoid type Arteriosclerotic dementia. Alcohol dependence syndrome
CTREPORT Old infarction secondary to cerebral atrophy Inconclusive Basal ganglia calcification Normal Normal Inconclusive Normal Brain tumour Brain tumour Brain damage secondary to trauma normal Normal (change not due to CT) Multiple cerebral infarctions Cerebral atrophy Old cerebral infarction Normal Brain tumour Normal Cerebral atrophy Old cerebral infarction Brain tumour
FINAL DIAGNOSIS Other organic psychotic condition Affective psychosis Dementia Pre-Senile Dementia Senile Dementia + acute confusional state Schizophrenic psychosis - paranoid type Schizophrenic psychosis - paranoid type Brain tumour Brain tumour (originally thought to be encephaliIis) Non psychotic mental disorder following organic brain damage Neurotic depression Catatonic schizophrenia Arteriosclerotic dementia Alcohol dependence syndrome Head injury & alcohol dependence syndrome Neurotic depression Brain tumour Organic psychotic condition Epilepsy and mental retardation Senile Dementia Brain tumour
Normal Normal Normal Hydrocephalus and cerebral atrophy Normal Normal Brain tumour Cerebral atrophy Normal Cerebral infarction Cerebral atrophy Normal Normal Cerebral atrophy
Schizophrenic psychosis - paranoid type Schizophrenic psychosis - paranoid type Schizophrenic psychosis - hebephrenic type Senile Dementia. Residual schizophrenia
Normal Minor cortical atrophy Normal Normal Cerebral atrophy Normal Cerebral atrophy Normal Normal Normal Normal Brain tumour (post hypophysectomy Cerebral atrophy Normal Normal Normal Normal Cerebral infarction Inconclusive
Affective psychosis Neurotic depression Korsakov's psychosis Transient organic psychotic condition (Encephalitis) Affective disorder Transient organic psychotic condition Senile Dementia Anxiety state Schizophrenic psychosis - paranoid type Dementia Organic psychotic condition Schizophrenic psychosis - paranoid type and brain tumour
Affective psychosis Hysterical personality disorder Brain tumour Pre-Senile Dementia Paranoid state Arteriosclerotic dementia Other organic psychotic condition (Neurosyphillis) Schizophrenic psychosis - schizoaffective type Acute schizophrenic episode Organic psychotic condition
Pre-Senile Dementia Para~oid state Acute schizophrenic episode Anxiety state Affective disorder Schizophrenic psychosis .- paranoid type Arteriosclerotic dementia, alcohol dependence syndrome
I.J.M.S. July, 1989
180 Colohan et al.
view" following hypophysectomy. The range excluding this patient was 5 days to 298 days and the mean length of stay was 62 ± 51 (S.D.) days. The duration of time that elapsed between admission and the performance of CT varied between one day and 342 days. Five patients had their CT scans following discharge from hospital. The mean duration from admission to CT scan was 50 ± 57 (S.D.) days. Twenty-six patients (48.1 %) showed evidence of organicity (as described above) in their mental status examination which indicated the possibility of an organic basis for their symptoms. Eleven of these patients were subsequently diagnosed as suffering from chronic organic reactions. Fifteen were diagnosed as suffering either from conditions with an organic basis other than a chronic organic reaction e.g. neurosyphilis, epilepsy, meningioma, or from non-organic conditions. Neurological and physical examination was definitely abnormal in 14 patients. Routine laboratory tests e.g. FBC, ESR, and U & E were abnormal in 18 patients (33.3%). Psychological testing was carried out on 26 patients. In 14 of these (53.8%) it suggested the presence of an organic illness. Electroencephalography was performed on 31 patients. The results were reported as definitely abnormal in 17 (54.8%). Forty-two patients were referred for CT scan by a psychiatrist, 10 patients were referred by a psychiatrist to a neurologist who then ordered a CT scan, and 2 patients were referred by a psychiatrist to a general hospital where a CT scan was subsequently ordered. The clinical diagnoses before and after scanning ofthe patients are shown in table 1. 24 CT scans were reported abnormal: The commonest abnormality reported
was atrophy with no other finding (9 patients), followed by infarction (6 patients) and tumor (6 patients). (One of these patients had a post hypophysectomy review scan). The remaining 3 scans demonstrated basal ganglia calcification, hydrocephalus and evidence of trauma. The scan results significantly affected the diagnosis, management or prognosis in six patients. These could not be distinguished by age or sex distribution from those whose management was unaltered by CT, or the number of days elapsing from admission to CT, but were more likely to suffer from cerebral neoplasm and to be referred to a neurologist (Table 2). The only clinical feature showing a statistically significant association with subsequent abnormality on CT, was the mental state examination (P < 0.05). Discussion Since the introduction of CT scanning, an increasing number of scans are being requested for patients in many specialities. Our results suggest that this trend also applies to psychiatry. Nevertheless, in our study the overall ~rcentage of scans performed on all patients admitted to St. John of God Hospital was less than 1% over a three year period. A total of 24 scans (44.4%) were abnorm~l.. This is comparable to the percentage of abnormalities noted by Roberts and Lishman l2 (50%) using similar criteria. However, neither of these studies are a true reflection of the overall prevalence ofCT abnormality in psychiatric patients. The majority of studies looking at CT scanning in psychiatry have been performed on selected groups of patients. Owens 13 reported a study of non-dementedpsychotic patients of whom 7.4 %
TABLE II
Influence of cr on subsequent management. No Number Age Days from admission to CT Presence of cerebral neoplasm Referred to a neurologist
* P< 0.05
48 (23M 25F) 51.7 ± 18.7
Yes 6 (2M 4F) 48.3
± 13.5
53±62
34±22
1/48
5/6*
19/48
6/6*
had conditions that were potentially remediable or whose diagnosis was influenced as a result of a CT scan. Although these patients were randomly chosen for the procedure, there was selectivity in thatall were chronic schizophrenics and showed no clinical evidence of dementia. Other factors which may influence the prevalence of abnormality on CT scanning are the inclusion ofpatients with focal neurological signs and the over-representation of elderly patients. Although we feel that our study demonstrates the influence ofthese factors, one specific aim was to identify the single best predictor of CT abnormality for the clinician and to assess the influence ofCT scanning on subsequent management. In our study, CT played a majorrole in establishing a diagnosis or influencing the management or prognosis in 6 patients. Four of these patients had brain tumours, one had encephalitis and in a further patient, a brain tumour was suspected but excluded by CT. In all 6 patients, a suspicion of organicity was aroused by the presenting complaint. In 5 of these cases, the mental status examination was not consistent with a functional psychiatric illness. It is noteworthy that only one of the five patients with serious organic conditions had an abnormal physical examination and none had abnormal laboratory test results. Our study shows that the diagnosis, management or prognosis was significantly influenced in 11.1 % of psychiatric patients scanned. This figure is generally comparable to those ofRoberts and Lishman 12,11.7%, and of Larson l 4, 4.8%. This high percentage of patients in whom CT significantly affects the outcome would appear to be at variance with Ashworth'slS assertion that scans are being requested more frequently in patients with psychiatric disorders, but in general they are of little diagnostic value. Of the 27 patients whose scans were reported abnormal or inconclusive, 9 had a clinical diagnosis of dementia. At first appearance CT scanning would seem an expensive diagnostic tool, but viewed in the context of the social and financial burden that a diagnosis of dementia implies, the value of CT in detecting the small number of reversible
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dementias is great. Although many chronic organic reactions are indistinguishable clinically, some have a chID;"acteristic appearance on CT, e.g. Pick's disease, Huntingtons Chorea, and sometimes multiinfarct dementia16. Potentially reversible chronic organic reactions may be noted on CT, e.g. chronic sub-dural haemorrhage, resectable brain neoplasm or cerebral abcess. The diagnosis of the chronic organic reaction cannot however be made solely on radiological criteria 17. As physical examination and laboratory tests were not good indicators of CT abnormality, we examined the role of EEG and psychological testing, as predictors of CT abnormality. Though not all patients underwent these examinations, neither showed any statistically significant association with abnormality onCT scan. Ofthose who hadEEG's only 16.2% were reported as being normal; 54.8% showed definite abnormality; and 29% showed non-specific abnormality. The high proportion of non-specific abnormality reduced the value ofthis investigation for predicting CT abnormality. From our study, it was apparent that the single significant correlate of CT abnormality was the mental'state examination. A standardised assessment of mental state, the Mini-Mental State Examination, which tests orientation, memory, attention, the ability to name, to follow verbal and written commands, to write a sentence spontaneously and to copy a complex polygon, was developed by Folstein, Folstein and McHugh 18 , and has been shown to identify patients with abnormal CT scans 19. Furthermore, it appears that the results of the two subtests of the Mini-Mental State Examination, the "Serial Sevens" Test and the Spell "World" Backwards Test, when combined can distinguish
patients with cerebral atrophy with or without focal lesions from patients with focal lesions only19. As patients in the former group are less likely to have clinically detectable neurological abnormalities, it is possible that the Mini-Mental State Examination incorporated into the routine mental state examination and taken in conjunction with a history and physical examination, might improve the accuracy of prediction of CT abnormality in psychiatric patients. In conclusion, it appears that CT is being judiciously used by psychiatrists and that it provides information applicable to diagnosis, managementorprognosis in a significant number of cases. The importanceofa careful mental state examination is evident and we recommend that a further study be undertaken to ascertain whether the use of a test such as the Mini-Mental StateExamination would improve the relative efficacy of utilistation of what is still an expensive and relatively scarce diagnostic resource, Acknowledgement This work was supported by the St. John of God Order.
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