Pattern of Computed Tomography Findings in Cerebrovascular

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Pattern of Computed Tomography Findings in Cerebrovascular

  1. 1. European Journal of Scientific Research ISSN 1450-216X Vol.34 No.1 (2009), pp.104-109 © EuroJournals Publishing, Inc. 2009 http://www.eurojournals.com/ejsr.htm Pattern of Computed Tomography Findings in Cerebrovascular Accident Patients in South-Eastern Nigeria – A Retrospective Study of 480 Patients C.U. Eze Correspondence Authors Department of Medical Radiography and Radiological Sciences Faculty of Health Sciences and Technology, College of Medicine, University of Nigeria Enugu Campus, Enugu, Enugu State, Nigeria Tel: +2348052805214 E-mail: ezecharlesu@yahoo.com A.O. Okaro Department of Medical Radiography and Radiological Sciences Faculty of Health Sciences and Technology, College of Medicine University of Nigeria Enugu Campus, Enugu State, Nigeria C. C. Ohagwu Department of Radiography and Radiological Sciences, Faculty of Health Sciences and Technology College of Health Sciences, Nnamdi Azikiwe University, Nnewi Campus Nnewi, Anambra State, Nigeria Abstract Background: Cerebrovascular accident (CVA) accounts for a significant proportion of neurological disorders seen in tertiary hospitals in Nigeria and carries a high morbidity and mortality statistics. Aim: To evaluate the pattern of computed tomography (CT) findings in patients with clinically diagnosed CVA who underwent CT imaging. Patients and Methods: A retrospective study of 480 patients with clinically suspected CVA, who underwent CT imaging at the University of Nigeria Teaching Hospital, Enugu, Nigeria between January, 2007 and December, 2008 was conducted. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 14.0. Results: The incidence of CVA was significantly higher in males than in females (72.71%, n = 349 Vs 27.29%, n = 131; ρ < 0.05). The most frequently affected age group was the 50 – 59 years age group (32.92%, n = 158). The incidence of ischaemic CVA was significantly higher than haemorrhagic CVA in the general population (56.66%, n = 272 Vs 23.13%, n = 111; ρ < 0.05). The incidence of ischaemic CVA was significantly higher than haemorrhagic CVA in males (45.65%, n = 219 Vs 17.29%, n = 83; ρ < 0.05) and in females (1 1.04%, n = 53 Vs 5.83%, n = 28; ρ < 0.05). Various types of brain tumuors were the commonly encountered findings at CT that clinically mimicked CVA, accounting for 4.38% (n = 21) of all the cases evaluated. Haemorrhagic CVA was significantly more in patients aged between 60 and 69 years than the rest of the patients while ischaemic CVA
  2. 2. Pattern of Computed Tomography Findings in Cerebrovascular Accident Patients in South-Eastern Nigeria – A Retrospective Study of 480 Patients 105 was significantly more in patients aged between 50 and 59 years than the rest of the patients (ρ < 0.05). Conclusion: The result of the study showed that there is a male preponderance in the incidence of both haemorrhagic and ischaemic CVA. There is also a preponderance of ischaemic CVA over haemorrhagic CVA. A few intracranial pathologies that mimic CVA are misdiagnosed as CVA clinically. Keywords: Cerebrovascular accident, Computed tomography, Findings, Pattern, South- Eastern Nigeria. 1. Introduction Cerebrovascular accident (CVA) or stroke occurs when the blood supply to the brain is disturbed in some ways. As a result, brain cells are starved of oxygen causing some cells to die and leaving others damaged. CVA can be defined as a focal neurological deficit of vascular origin lasting more than 24 hours and is often preceded by transient ischaemic attack in 10 – 15% of the cases.1 The symptoms of CVA are usually sufficiently severe and abrupt to force the patient to seek immediate medical aid. CVA has been reported as a cause of death and neurological disability in adults and imposes a heavy emotional and financial burden on the family of the patient and society.2 A study in America reported that stroke was the third most common cause of death in the United States, approximating 7% and trailing only heart disease and cancer.3 It carries a high mortality rate and is a leading cause of disability.3 CVA is the most prevalent neurological disorder in both mortality and morbidity and is caused by an abnormality in the blood supply to the brain.4 A variety of processes that involves the blood vessels may lead to luminal compromise and cerebral infarction.5 CVA may be due to infarction (ischaemic stroke) in 80% of the cases or haemorrhage in the remaining 20%.1 Haemorrhagic CVA is usually associated with uncontrolled and longstanding hypertension.1 Clinically, ischaemic stroke presents as a focal neurological deficit of sudden onset but there may be step-like progression with headache, complete loss of consciousness and vomiting as common symptoms unless the brainstem is involved.1 Clinical presentation of haemorrhagic stroke varies according to the site, type and location of the bleed. Headache, vomiting, focal neurological deficit and decreased level of consciousness are characteristic symptoms and there may be quick progression to coma.1 There is a potential for prominent impact for radiologic imaging on care for patient with acute 6 stroke. Stroke remains one of the most important clinical diagnoses for which patients are referred to the radiologist for emergent imaging7, as timely and accurate diagnoses would help in the management of the patient. Computed tomography (CT) is very important in diagnosis of CVA as it shows if it is haemorrhagic or ischaemic.8 CT detects haemorrhage and other lesions that may mimic stroke such as tumours, subdural/extradural haematomas and abscesses.9 Because of greater penetration of CT scanners, speed of examination and absence of magnetic resonance imaging (MRI) safety considerations, CT has become a first-line imaging evaluation of patients with symptoms of CVA.7 There is paucity of literature on CT studies of patients with CVA in this locality. This study was aimed at evaluating the pattern of common CT findings in patients with CVA in this locality to provide the needed baseline data. 2. Patients and Methods A retrospective study of 480 patients, who were referred for CT imaging of the brain for clinically suspected CVA between January, 2007 and December, 2008 was conducted. The study was carried out in the Department of Radiation Medicine, University of Nigeria Teaching Hospital (UNTH), Ituku-
  3. 3. 106 C.U. Eze, A.O. Okaro and C. C. Ohagwu Ozalla, Enugu, South-Eastern Nigeria. The teaching hospital is a major referral centre for CVA patients in the South-East geopolitical zone of Nigeria. Permission to carry out the study was obtained from the hospital management before the commencement of the study. All the patients referred for CT evaluation of clinically diagnosed CVA were scanned using a fifth generation spiral (helical) Siemens™ CT machine with the following specifications: maximum kilovoltage – 140kV, minimum kilovoltage – 40kV, maximum milliamperage – 500mA, minimum milliamperage – 50mA, and maximum tilting angle - 60º. Scanning was done in axial cuts from the base of the skull to the vertex. Slice thickness of 2mm was used from the base of the skull to the sella turcica and then 3mm for the rest of the scan. All the images were reformatted in all the cases for better analysis. The data collected were analyzed using the Statistical Package for Social Sciences (SPSS) version 14.0. Statistical tests were done with two-tailed t-test with ρ < 0.05 to indicate statistical significance. 3. Results A total of 480 patients with clinically suspected CVA who were referred for CT imaging during the period covered by the study were evaluated. The patients comprised of 349 (72.29%) males and 131 (27.29%) females as shown in table 1. Table 1: Age and gender distribution of the patients evaluated Age (Years) Male Female Total 40 - 49 86 (17.91%) 28 (5.83%) 114 (23.75%) 50 – 59 112 (23.33%) 46 (9.58%) 158 (32.92%) 60 – 69 90 (18.75%) 38 (7.92%) 128 (26.67%) 70 – 79 32 (6.67%) 17 (3.54%) 49 (10.20%) >= 80 29 (6.04%) 2 (0.42%) 31 (6.46%) Total 349 (72.70%) 131 (27.30%) 480 (100%) There were significantly more male patients being affected than females (ρ < 0.05). The patients’ ages range from 40 years to over 80 years. Table 1 also shows that patients aged between 50 and 59 years were the most affected group with a frequency of 158 patients (32.92%) while the least affected were patients who were 80 years or more with a frequency of 31 patients (6.46%). Table 2 shows the distribution of types of CVA and other findings seen at CT according to gender of the patients. It shows that ischaemic CVA was the more common CVA in both males (219 patients; 45.63%, ρ < 0.05) and females (53 patients; 11.04%, ρ < 0.05) than haemorrhagic CVA. There is a male to female ratio of 4.1: 1 for ischaemic CVA and 3: 1 for haemorrhagic CVA. Other findings that clinically mimicked CVA seen at CT were cerebral aneurysm found in only 9 patients (1.87%; all males) and various brain tumuors found in 21 patients (4.38%). Table 2: Distribution of types of CVA and other findings at CT according to the gender of the patients CT Findings Male Female Total Haemorrhagic CVA 83 (17.29%) 28 (5.83%) 111 (23.13%) Ischaemic CVA 219 (45.63%) 53 (11.04%) 272 (56.66%) Cerebral aneurysm 9 (1.88%) 0 (0%) 9 (1.87%) Brain tumours 13 (2.71%) 8 (1.67%) 21 (4.38%) Normal CT findings 47 (9.79%) 20 (4.17%) 67 (13.96%) Total 371 (77.29%) 109 (22.71%) 480 (100%) The tumuors were seen in 13 males (2.71%) and 8 females (1.67%). Normal findings at CT were encountered in 67 patients (13.96%); 47 males (9.79%) and 20 females (4.17%).
  4. 4. Pattern of Computed Tomography Findings in Cerebrovascular Accident Patients in South-Eastern Nigeria – A Retrospective Study of 480 Patients 107 Table 3 shows the distribution of CT findings according to the age of the patients. Haemorrhagic CVA was the commonest finding in patients aged between 60 and 69 years with a frequency of 60 patients (12.50%, ρ < 0.05)) while ischaemic CVA was the commonest finding in patients aged between 50 and 59 years with a frequency of 113 patients (23.54%, ρ < 0.05). Table 3: Distribution of CT findings according to patients’ ages CT Findings Age (Years) Haemorrhagic Ischaemic Cerebral Brain Normal Total CVA CVA aneurysm tumuors findings 40 - 49 2 (0.42%) 70 (14.58%) 3 (0.63%) 0 (0%) 39 (8.12%) 114 (23.75%) 50 - 59 41 (8.54%) 113 (23.54%) 1 (0.21%) 1 (0.21%) 2 (0.42%) 158 (32.92%) 60 - 69 60 (12.50%) 68 (14.17%) 0 (0%) 0 (0%) 0 (0%) 128 (26.67%) 70 - 79 5 (1.04%) 11 (2.29%) 4 (0.83%) 11 (2.29%) 18 (3.75%) 49 (10.20%) >= 80 3 (0.63%) 10 (2.08%) 1 (0.21%) 9 (1.86%) 8 (1.66%) 31 (6.64%) Total 111 (23.13%) 272 (56.66%) 9 (1.88%) 21 (4.38%) 67 (13.95%) 480 (100%) Cerebral aneurysm was commonest among the very elderly patients aged between 70 and 79 years with a frequency of 4 patients (0.83%) as shown in table 3. The highest incidence of brain tumuor (1.86%; n = 9) was also found in patients aged between 70 and 79 years as shown in table 3. Normal findings at CT was mostly encountered in patients between 40 and 49 years (8.12%; n = 39) as shown in table 3. 4. Discussion Cerebrovascular accident is a leading cause of death and disability in the elderly. Computed tomography which produces series of cross-sectional images plays important part in definitive diagnosis of CVA. It is becoming increasingly available locally and is assuming the first-line imaging modality status in cases of CVA where they are available. The result of our study shows that there is a male preponderance over female in the incidence of both haemorrhagic and ischaemic CVA. There are male to female ratios of 4.1: 1 for ischaemic CVA and 3: 1 for haemorrhagic CVA recorded in this study. This finding is similar to the report of Ikeh et al10 who reported 5.7: 2 male to female ratio for cerebral infarction in South-East Ngeria. A similar study in South-West Nigeria reported a male to female ratio 1.3: 1.2 Also, a retrospective study of medical admissions at the University of Nigeria Teaching Hospital, Enugu reported a male gender preponderance.11 Stroke or CVA was among the cases reviewed in the study. This male preponderance in CVA suggests that men have more risk factors for CVA such as hypertension and diabetes mellitus than women. Although, we did not review the lifestyle and habits of the patients, we think that men are more involved in high-risk habits such as smoking and alcoholism, and probably work harder under stressful conditions. These factors are closely associated with hypertension and other cardiac diseases which may elicit CVA. There were more cases of ischaemic CVA than haemorrhagic CVA recorded in this study. This finding is similar to others that reported the same trend.2,1 Our study also revealed a small proportion of mimics of CVA such as cerebral aneurysms and brain tumuors which can only be definitively diagnosed at CT. These findings suggest that the recommendation that CT imaging be carried out in all cases of suspected CVA should be adhered to.2,8,9,12,13 Even though we have more male patients as victims of CVA, a previous study reported that there was no gender preference in utilization of neuroimaging facilities.14 A previous study reported that the highest incidence of CVA was found among the elderly, those beyond middle ages.15 The present study in South-Eastern Nigeria recorded the highest incidence of CVA, both ischaemic and haemorrhagic in the elderly. This may be attributed to the increase in the
  5. 5. 108 C.U. Eze, A.O. Okaro and C. C. Ohagwu risk factors for CVA notably hypertension with age. There may be a low awareness level about hypertension and its management among this elderly people in our locality. Though, not many cases of haemorrhagic CVA were recorded, it should be recalled that haemorrhgic CVA is a direct consequence of uncontrolled and longstanding hypertension.1 Computed tomography plays a very important role in definitive diagnosis of CVA paving the way for timely and accurate management of the patient. Non-contrast head CT (NCCT) is being advocated as one of the mainstays of early stroke diagnosis.16-24 CT angiography (CTA) has become established as a means of diagnosing the vascular occlusion of acute stroke because it can reliably detect filling defects within the circle of Willis or its proximal tributaries25, and parenchymal filling- perfusion defects indicative of whole-brain perfused blood volume.20 5. Conclusion In conclusion, our study revealed male gender preponderance in the incidences of haemorrahgic and ischaemic CVA. There is also a preponderance of ischaemic CVA than haemorrhagic CVA in the general population. A few cases mimicking CVA may be misdiagnosed as CVA clinically. The result of this study may be of use to neurologists in clinical decision making as to which imaging modality will provide accurate and timely diagnosis of CVA. References [1] Holmes JE, Mirsa RR. A – Z of emergency radiology. New York: Cambridge University Press. 2004; Pp. 15 – 17. [2] Komolafe MA, Komolafe EO, Fatoye F, Adetiloye V, Asaleye C, Famurewa O, Mosaku S, Amusa Y. Profile of stroke in Nigerians: a prospective clinical study. African Journal of Neurological Sciences 2007; 26 (1): 5 – 13. [3] Vo KD, Lin W, Lee JM. Evidence-based neuroimaging in acute ischaemic stroke. Neuroimaging Clin N Am 2003; 13: 167 – 183. [4] Kumar V, Abbas AK, Fantso N. Robbins and Cotran pathological basis of disease 7th edition. India: Thomson Press (India) Ltd. 2005; P. 1361. [5] Lie J. Classification and histopathologic spectrum of central nervous system vasculitis. Neurol Clin 1997; 15: 805. [6] Rother J. CT and MRI in diagnosis of acute stroke and their role in thrombolysis. Thromb Res 2001; 103 (Suppl 1): S 125 – 133. [7] Mullins ME. Modern emergent stroke imaging: pearls, protocols and pitfalls. Radiol Clin N Am 2006; 44: 41 – 62. [8] Allen CMC, Lueck CJ. Diseases of the central nervous system. In: Boon N, Colledge N, Walker B, Hunter J. (eds). Davidson’s principles and practice of medicine 20th edition. United Kingdom: Churchill Livingstone. 2006; P. 979. [9] Smith WS, Johnston SC, Easton JD. Cerebrovascular diseases. In: Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL. (eds). Harrison’s principles of internal medicine 16th edition. New York: McGraw-Hill Medical Publishing Division. 2005; Pp. 2372 – 2392. [10] Ikeh VO, Onwuekwe IO, Nwosu CM, Nwabueze AC. Cardiogenic embolisation and ischaemic stroke: a review of cases seen at The University of Nigeria Teaching Hospital, Enugu. Nigerian Journal of Medical Investigation and Practice 2003; 4: 4-7. [11] Ike SO. The pattern of admissions into medical wards of the University of Nigeria Teaching Hospital, Enugu. Nigerian Journal of Clinical Practice 2008;11 (3): 185 – 192. [12] Snow RB, Zimmerman RD, Gandy SE, Deck MDF. Comparison of magnetic resonance imaging and computed tomography in evaluation of intracranial diseases. Neurosurgery 1986; 18: 45 – 52.
  6. 6. Pattern of Computed Tomography Findings in Cerebrovascular Accident Patients in South-Eastern Nigeria – A Retrospective Study of 480 Patients 109 [13] Celani MG, Ceravolo MG, Duca E, Minciotti P, Caputo N, Onandeni M, Ricci S, Proveniciali L. Was it infarction or haemorrhage ? A clinical diagnostic means of the Allen Score. J Neurol 1992; 239 (7): 411 – 413. [14] Karpal MK, Fang J, Hill MD, Silver F, Richards J, Jaigobin C, Cheung AM. Sex differences in stroke care and outcome. Stroke 2005; 36 (4): 809 – 814. [15] Mabadeje BAF. Management of hypertension. Nigerian Medical Journal 1971; 4: 265 [16] Kidwell CS, Villablanca JP, Saver JL. Advances in neuroimaging of acute stroke. Curr Atheroscler Rep 2000; 2: 126 – 135. [17] Heiss WD, Forsting M, Diener HC. Imaging in cerebrovascular disease. Curr Opin Neurol 2001; 14: 67 – 75. [18] Schellinger PD, Jansen O, Fiebach JB, et. al. Feasibility and practicality of MR imaging of stroke in the management of hyperacute cerebral ischaemia. Am J Neuroradiol 2000; 21:1184 – 1189. [19] Rosenwasser RH, Armonda RA. Diagnostic imaging for stroke. Clin Neurosurg 2000; 46: 237 – 260. [20] Nakano S, Iseda T, Kawano H, et. al. Correlation of early CT signs in deep middle cerebral artery territories with angiographically confirmed site of arterial occlusion. AJNR Am J Neuroradiol 2001; 22: 654 – 659. [21] Moonis M, Fisher M. Imaging of acute stroke. Cerebrovasc Dis 2001; 11: 143 – 150. [22] Lee BI, Nam HS, Heo JH, et. al. Yonsei Stroke Registry: analysis of 1,000 patients with acute cerebral infarctions. Cerebrovasc Dis 2001; 12: 145 151. [23] Kilpatrick MM, Yonas H, Goldstein S, et. al. CT-based assessment of acute stroke: CT, CT angiography, and xenon-enhanced CT cerebral blood flow. Stroke 2001; 32: 2543 – 2549. [24] Gleason S, Furie KL, Lev MH, et. al. Potential influence of acute CT on inpatient costs in patients with ischaemic stroke. Acad Radiol 2001; 8: 955 – 964. [25] Lieberman G, Abramson R, Volkan K, et. al. Tutor versus computer: a prospective comparison of interactive tutorial and computer-assisted instruction in radiology education. Acad Radiol 2002; 9: 40 – 49.

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