Magnetic resonance imaging in chronic headache: our experiences and perspectives

Magnetic resonance imaging in chronic headache: our experiences and perspectives

Abstract

Background: Headache is a common symptomatology necessitating hospital consultations. Despite the prohibitive cost to patients in Nigeria, Magnetic resonance imaging has become an evaluating tool for headache.

Objectives: To determine the yield of cranial Magnetic resonance imaging and frequency of significant intracranial lesions among patients with chronic headache.

Methods: A three-year retrospective analysis of cranial Magnetic resonance images and records of patients referred to Medicaid Diagnostic Centre in Abuja, Nigeria on account of chronic headache was done. Data was analyzed using SAS software version nine point three.

Results: One hundred fifty patients aged nine to seventy-three years (mean equals thirty-nine point five years) with chronic headache were studied. There were fifty-four males and ninety-six females with a ratio of one to one point eight. Forty-eight percent and fifty-two percent had normal and abnormal Magnetic resonance imaging findings respectively. Although the number with abnormal Magnetic resonance imaging was higher than those with normal exams, this difference was not significant (P equals zero point six two four). The commonest neoplastic and non-neoplastic abnormalities were pituitary macroadenoma (four percent) and sinusitis (twenty-one point three percent) respectively.

Conclusion: In our study, Magnetic resonance imaging had a low diagnostic yield in patients with chronic headache. Therefore, it is expedient that physicians stratify patients with chronic headache based on red flag signs to determine the need for cranial Magnetic resonance imaging in view of financial burden.

Introduction

Headache is ranked among the ten most disabling conditions worldwide according to World Health Organization parameters. The lifespan prevalence of the various categories of headache varies from thirty-one percent to ninety-six percent.

Headache can be clinically described as acute, chronic or recurrent. Chronic daily headache (headache for greater than or equal to fifteen days per month for longer than three months) is a common and potentially disabling condition. Headache is further classified into primary and secondary with regards to an underlying organic etiology. Primary headaches do not have any underlying organic pathologic aetiology and are generally benign. It has been shown that most of the patients suffering from primary headache can be managed with primary care and do not need neuroimaging in most of the cases. They include migraine, tension headache and cluster headaches. Conversely, secondary headaches are related to an underlying organic condition. Aetiologies of secondary headaches range from extra-cranial benign conditions such as sinusitis or mastoiditis to life-threatening intracranial pathology like subarachnoid hemorrhage or brain tumors. Brain tumors however account for less than zero point one percent in the lifetime prevalence as a cause of headache. Although headache is one of the commonest presenting complaints in the general outpatient department of most hospitals, only about ten percent of patients with chronic headache have a secondary cause. And though most causes of headaches are benign, it does not obviate the concern of the physician to alleviate the fears of patients especially in cases of chronic or recurrent headaches. In patients with chronic headaches, secondary or organic causes always need to be considered, because when present they require prompt diagnosis and possible intervention.

Treatment of headache poses a diagnostic challenge to the physician because some potential aetiologies of headache may be life threatening. It has been shown that significant intracranial pathology can cause nothing more than a mild headache. Neuroimaging is therefore being used as a means of triage of headaches and assuring patients with primary headaches of the absence of potentially life-threatening underlying pathologies. Presently the cost of neuroimaging in Abuja ranges from twenty-seven dollars for two projections of a skull radiograph, to one hundred eighteen dollars for a cranial computed tomography scan and two hundred ten dollars for a cranial Magnetic resonance imaging (cost of neuroimaging in the index centre). In a resource-challenged environment like ours, the habitual use of cross-sectional neuroimaging, especially computed tomography and Magnetic resonance imaging have remained controversial because data on the effectiveness of this strategy in identifying patients with treatable lesions are conflicting or lacking in developing countries like Nigeria.

Magnetic resonance imaging is often resorted to as an imaging modality of choice because of its non-ionizing property, especially with regards to the evaluation of children and pregnant females. Magnetic resonance imaging has good spatial resolution and multipolar capabilities and demonstrates more superior soft tissue contrast than computed Tomography scans and plain films, making it the ideal examination of the brain. In addition, some Magnetic resonance imaging studies can be done without the need of administering intravenous contrast, unlike computed Tomography or conventional angiography. Magnetic resonance imaging is more sensitive than computed Tomography in detecting intracranial pathologies and advanced techniques such as diffusion-weighted imaging, Magnetic resonance spectroscopy and perfusion studies, allow for enhanced characterization of lesions.