Is The Routine CT Head Scan Justified for Psychiatric Patients? A Prospective Study

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1 RESEARCH PAPERS Is The Routine CT Head Scan Justified for Psychiatric Patients? A Prospective Study Jambur Ananth, M.D., Reda Gamal, M.D., Milton Miller, M.D., Marcy Wohl, R.N., Steven Vandewater, Ph.D. Harbor UCLA Medical Center, Torrance, California Submitted: September 1, 1992 Accepted: January 21, 1993 Thirty-four psychiatric patients, assessed for a physical illness that was missed during diagnosis, underwent a CT scan. After investigation, the diagnosis of 14 patients changed from a functional to an organic illness. In nine patients, the CT scan was reported to be abnormal, and yet only two were diagnosed as having an organic syndrome. In seven patients, the CT scan was normal but the patients had an undisputed organic brain syndrome. These findings indicate that the use of CT scans should be restricted to cases in which the diagnosis is seriously in question. The clinical findings should dictate the use of CT scans either to clarify or to complement them. Key Words: CT scan, diagnosis of organic brain syndrome, psychosis and CT scan, neurobiology and psychiatry INTRODUCTION Often, disorders of the central nervous system (the brain and spinal cord) resulting from head trauma, hemorrhage inside the cranium, tumors, aneurysms, and seizures, etc., may initially manifest themselves with psychiatric symptoms, such as disorientation, hallucinations, altered thought process and catatonia. Hence, it is not surprising that a psychiatrist may be the first physician to evaluate patients with occult neurological disorders. The clinician evaluating a patient with a psychiatric illness invariably considers the possibility that a medical illness is responsible for the psychiatric symptomatology, and therefore some biological data, including a personal and family history of physical illness and a systems review (list of all the symptoms belonging to various organ systems such as cardiovascular or respiratory), is gathered. Even a complete neurological examination conducted during the initial assessment may not detect the clinical problem. In the absence of clear-cut neurological signs upon these examinations, computed axial tomography (CT) scan of the brain is considered to be a reliable means of detecting neurological diseases. The CT scan, a more J PsychiatrNeurosci, VoL 18, No. 2, 1993 advanced X-ray, can take cross-sectional and three-dimensional images of the brain. It also determines tissue densities to locate the focal area of structural disease. It is of special significance in psychiatry for a number of reasons. Being a non-invasive technique, it causes no pain and patients therefore do not object to the procedure. Furthermore, since there are no specific blood tests or X-rays to diagnose a mental illness, as with high blood sugar for the diagnosis ofdiabetes, this diagnostic procedure is enthusiastically supported for the evaluation of patients with a suspected organic illness. Although the use of CT scans has been advocated for various conditions, there are no guidelines for its use with psychiatric patients. For example, in psychiatry it has been recommended for various disorders, such as dementia and atypical psychosis (psychosis that does not fall under the category of schizophrenia, bipolar disorder, etc.). In fact, some psychiatrists recommend CT scans for all first admissions to hospital (Weinberger 1984). These recommended uses of CT scans can be broadly categorized into two groups: 1. to confin organic illness - inferring that definitive 69

2 70 Journal ofpsychiatry & Neuroscience VoL 18., No physical illness such as seizure disorder, stroke, alcohol and/or drug use, can mimic psychiatric disorders; and 2. as a preventive measure to screen all psychiatric patients - similar to the use of blood tests or urinalysis. To decide on the proper use of CT scans, one should evaluate both the cost/benefit ratio and its diagnostic value. If it proves to be efficient in detecting organicity in the psychiatric population, it will not only become a valuable clinical investigation tool but will also create an adequate testing ground for evaluating and improving the clinical examination of psychiatric patients with organic brain syndromes and help develop solid biological data. None of the available studies provide any evidence on the role of CT scan as a diagnostic tool in psychiatry. In a retrospective study of 123 patients who underwent a CT scan to rule out an organic illness, Larson et al (1981) found that 105 patients were identified as normal. However, the sample included 43 patients with brain atrophy which did not affect their management, 12 patients with focal neurological disease, which included three who had a brain tumor, three who had subdural hematoma, five who had had a cerebrovascular accident and one who had post-surgical changes. For six of these 12 patients, the scans resulted in a clear diagnosis and therefore better clinical management. The study also revealed that patients for which the CT scan findings were true positive for neurological disease also had focal neurological lesions. Hence, they concluded that the rule-out approach was not useful. It is also important to note that patients with a chronic illness may not have a neurological illness detectable by CT scan. Holt et al (1982) had similar findings but a different interpretation of the data. In a review of 99 general hospital psychiatric consultations, they found that CT scans played a major role in clarifying the diagnosis in 25% of the patients. In both of these studies, it is difficult to interpret the data, since they were not random samples, but rather a selected population prone to have an organic cause for their illness. Owens et al (1980) conducted a study of 136 randomly selected psychiatric patients and noted that in the case of 11 patients, the CT scan influenced the diagnosis and, in three cases, they were treatable. Evans (1982) found eight cases of discrete structural lesions of the brain among 100 patients investigated for the cause of their dementia. In another retrospective study of 135 patients with suspected organic brain disease, CT scan results revealed only three patients with focal neurological disease, indicating that CT scans are not helpful (Tsai and Tsang 1981). There are some drawbacks, however, to the use of CT scans on a large scale. The dangers of X-ray exposure and the costs involved preclude its routine use. In addition, the effectiveness of CT scan in detecting organic illnesses, its area of application and the extent of its usefulness have not been delineated clearly. These factors prompted this evaluation of the application of CT scans in the diagnosis of organic etiologies (causative factors) in psychiatric patients. Table 1 Initial and final diagnoses of the experimental population Diagnosis Initial Final Schizophrenia Bipolar disorder 5 4 Atypical psychosis 3 0 Seizure disorder 1 2 Adjustment disorder 1 0 Mixed organic syndrome 2 5 Organic delusional syndrome I I Alcoholic hallucinosis 0 1 Multiinfarct dementia 0 2 Cocaine psychosis 0 1 Alcohol dependence 0 1 Alcohol dementia 0 2 Delirium 0 2 Experimental population The experimental population consisted of 34 patients who were randomly selected from hospitalized psychiatric patients at the Metropolitan State Hospital. The exclusion criteria were as follows: patient's refusal to participate in the study, inability to comprehend, possibility of discharge before the expected date of completion of the tests, and disapproval by the ward staff based on the possibility that the patient would elope or become violent. The population consisted of 16 female patients and 18 male patients with an average age of 36.3 years (range = 24 to 58 years). Twentyone patients were diagnosed by the hospital physicians with schizophrenia, five with bipolar disorder, three with atypical psychosis, one with epilepsy with psychosis, one with organic delusional syndrome, two with mixed organic syndrome and one with adjustment disorder with depressed mood (see Table 1). These patients had been hospitalized for an average of 15 days before entering the study (range = one to 76 days). None of the patients had an initial diagnosis of recent (within the past six months) or past substance abuse. In all instances, the physicians on the ward had completed the patients' diagnostic evaluations and treatment plans. All the patients therefore had two sets of diagnoses: the initial diagnosis made by the ward physicians and the second diagnosis made by the research team. Experimental procedure After the patients were selected, six types ofdata sets were collected: historical, psychiatric, physical, biochemical, radiological and neurophysiological. Almost all of the evaluation procedures were completed on the research unit. The unit

3 March 1993 Routine CT head scan 71 Patient Table 2 Relevance of the CT findings to a change in diagnosis Age Sex Initial diagnosis CT findings Final diagnosis Change related to 29 Male Schizophrenia Attenuation of post-parietal Organic mental disorder CT scan and occipital area 38 Female Atypical psychosis Mild central atrophy Alcoholic dementia History and clinical findings 54 Male Mixed organic syndrome Mild cerebral atrophy Multiinfarct dementia History 35 Female Schizophrenia Right frontal area of density; Organic delusional disorder History no clinical significance 40 Male Schizophrenia Generalized atrophy Alzheimer's disease History and clinical findings 34 Male Schizophrenia Mild bifrontal atrophy Organic mental disorder CT scan and history not otherwise specified 55 Female Atypical psychosis Prominent sulci Multiinfarct dementia History and clinial findings 42 Female Schizophrenia Slight asymmetry of Sylvian fissures, left larger than right No change 50 Female Schizophrenia Mild atrophy left frontal lobe No change was organized and furnished so that patients could be interviewed individually and laboratory procedures and physical examinations could be conducted in privacy. On the first day, a psychiatrist interviewed the patient and completed the Diagnostic Interview Schedule (DIS). During the same interview, the Brief Psychiatric Rating Scale (BPRS) and a medical history form designed specifically for the study were also completed. The medical history form consisted of a symptom checklist, a checklist of current and past medical illness, injuries and allergies, questions about current medications and a family medical history. On the second day, physical and neurological examinations were conducted independently by a board-certified internist and a neurologist. Their findings were recorded on a standard form designed for the study. On the same day, EEGs and EKGs were recorded. Finally, CT scans ofthe brain were conducted. The CT scans were read by two neuroradiologists who were blind to the patient's history and the initial diagnosis. RESULTS A comparison ofthe ward physicians' diagnoses and those ofthe research team indicated that the diagnosis of 14 patients changed to that of an organic illness. As noted in Table 1, eight of the 21 patients with schizophrenia (38%) were found to have a number of organic disorders, compared with one of the five with bipolar disorder (20%). The diagnoses of the patients with atypical psychosis and one with an adjustment disorder were changed to that of an organic brain syndrome. CT scan abnormality and organicity In the cases of nine patients (five males and four females), CT scan results showed abnormalities (see Table 2). The average age of these nine patients was 41.1 years, in contrast to the average age of the total population (36.8 years). Initially, seven were diagnosed with schizophrenia, one with atypical psychosis and one with a mixed organic syndrome. As a result of our other investigations and considering the CT scan abnormalities, the diagnoses of five patients with schizophrenia and one with atypical psychosis were changed to that of organic psychosis. One other had already been diagnosed as having an organic disorder. Two patients whose diagnosis did not change showed mild atrophy on the CT scan, although the other investigations did not indicate organic illness. We looked at the factors (psychiatric and medical history, psychological testing, physical examination and CT scan) which helped most in arriving at a diagnosis. In carefully assessing the role of these investigations, we conclude that in two of the seven patients whose diagnosis changed from a psychiatric to an organic illness, the change was related only to the CT scan results. The following are the brief descriptions of these cases. Case 1 A 29-year-old male was hospitalized for an extended period with a diagnosis of catatonic schizophrenia. On the unit, he had auditory hallucinations, episodes of excitement, increased psychomotor activity, hyperarousal and was occasionally violent with a poor response to various antipsychotic drugs. No focal signs on the neurological examination or cognitive deficits on the mental examination were noted. A CT scan abnormality provided the first clue to organicity. One of his sisters later stated that she had dropped him when he was only a few days old, and that he had required surgery and been hospitalized for a month.

4 72 Journal ofpsychiatry & Neuroscience VoL 18., No. 2,1993 Patient Table 3 Change to a diagnosis of organic brain syndrome in patients with a negative CT scan Age Sex Initial diagnosis CT findings Final diagnosis Change related to 40 Female Schizophrenia Normal CT scan Delirium History and clinial findings 30 Male Schizophrenia Normal CT scan Alcohol abuse Clinial findings 28 Female Bipolar disorder Normal CT scan Cocaine abuse History 27 Male Schizophrenia Nornal CT scan Alcoholic dementia History and clinical fmdings 46 Male Atypical psychosis Normal CT scan Alcohoic hallucinosis History and clinical findings 27 Male Adjustment disorder Normal CT scan Epilepsy History and clinical findings 25 Male Schizophrenia Normal CT scan Delirium Clinical findings Case 2 A 34-year-old male was admitted to hospital, having been diagnosed with schizophrenia manifesting paranoid symptoms and a moderate to good response to neuroleptics. However, he was atypical in that he did not think properly or very concretely. The patient's history revealed a heavy use of amphetamines, PCP and alcohol during his youth and a history ofthree or four convulsions. The CT scan abnormality (frontal atrophy) and his history were useful in changing his diagnosis to organic mental disorder not otherwise specified. Organicity with negative CT scans Of the 34 patients, seven patients had an undisputed organic brain syndrome of varying etiologies (see Table 3). However, the CT scan did not reveal abnormalities in any of them. This group consisted of patients with the following initial diagnoses: three with schizophrenia, one with an affective disorder, one with atypical psychosis, one with an adjustment disorder, and one with organic delirium. The final diagnosis of organic psychosis varied in etiology: alcohol abuse - three patients; cocaine abuse - one; epilepsy - one; delirium - one; organic delusion syndrome - one. As indicated in Table 3, the patient's history and the clinical examination were the most useful in diagnosing organic brain syndrome. CONCLUSIONS Organic illness was detected in 14 of the 34 patients studied (41%). The CT scans generally did not reveal any specific or clear-cut abnormalities in our patient population. Of the nine patients who showed some changes (although not diagnostic) on the CT scans, the findings were considered useful in diagnosing organic illness only in two. On the other hand, seven patients who had normal CT scans were diagnosed as having organic brain syndromes, supported on clinical grounds. Thus, among the 14 patients whose diagnosis changed to that of an organic brain syndrome, only two were detected by a positive finding on the CT scan. As a side note, all three patients with atypical psychosis were diagnosed as having an organic brain syndrome. It may therefore be prudent to periodically review patients with a diagnosis of atypical psychosis. Why were CT scans not helpful in our diagnoses? CT scans generally are a useful diagnostic tool if there is a localized lesion in the brain, but psychiatric patients do not have an anatomic lesion as the basis of their illness. Also, the presence of an anatomical lesion does not always infer organic brain disease. For example, mild atrophy of the brain (a positive CT scan abnormality) often may not indicate psychiatric pathology. Conversely, a person with a normal scan may be suffering from a clinically clear-cut organic brain disease. Hence, the clinical findings should dictate the use of CT scans as a corroborative investigation either to clarify or to complement them when warranted but not to rule out a diagnosis. Final diagnosis should rest on clinical evidence and not on the CT scan report. In other words, it should be used in a similar manner to the way an EEG is used to diagnose neurological disorders. While the routine use of CT scans is not useful, they can be in cases where the diagnosis is seriously in question. Therefore, a careful history (both medical and psychiatric), physical examination and a psychiatric evaluation are vital to make a diagnosis and should not be overlooked because of the availability of a CT scan facility. ACKNOWLEDGEMENTS The authors wish to thank the administrative and clinical staff of the Metropolitan State Hospital for their help. The study

5 March 1993 Routine CT head scan 73 was supported by a Grant from the California State Department of Mental Health. REFERENCES Holt RE, Rawat SR, Beresford TP, Hall RCW (1982) Computed tomography of the brain and the psychiatric consultation. Psychosomatics 23: Larson EN, Mack LA, Watts B, Cromwell LD (1981) Computed tomography inpatients with psychiatric illness: advantage of rule in approach. Ann Intern Med 95: Owens DG, Johnston EC, Bydder GM(1980) Unsuspected organic disease in chronic schizophrenia demonstrated by computed tomography. J Neurol Neurosurg Psychiatry 43: Evans NJR (1982) Cranial computerized radiography in clinical psychiatry: 100 consecutive cases. Compr Psychiatry 23: Tsai L, Tsang M(1983) How can we avoid unnecessary CT scanning of psychiatric patients? J Clin Psychiatry 42: Weinberger DR (1984) Brain disease and psychiatric illness: When should a psychiatrist order a CAT scan? Am J Psychiatry 141: