Thyroid dose and cancer risk from head and neck computed tomography at two selected centres in Nigeria.

OBJECTIVE: The objective of this study was to evaluate the thyroid glands' radiation dose and the risk of thyroid cancer induction from head or neck computed tomography (CT) examinations. METHODS: In a prospective study, we evaluated all participants of all ages and sex referred for Head or Neck CT Scan at the University College Hospital, Ibadan and Me Cure Healthcare Limited, Ibadan, Oyo State, Nigeria. Thyroid radiation dose was estimated with impact scan calculator, and real-time dose measurement with thermoluminescent badge dosimeters (TLDs). Data were analysed and P < 0.05 was considered statistically significant. RESULTS: One hundred and sixty-three participants (128 adults and 35 children) participated in the study. In most participants (74%), the tube voltage was 120 kVp. The estimated median thyroid gland dose by the imPACT scan calculator was 4.95 mGy (range = 1.20-30.0 mGy) and 4.40 mGy (range = 3.0-5.10 mGy), while the real-time dose measured by the TLD was 4.79 mGy (range = 1.73-96.7 mGy) and 2.33 mGy (range = 1.20-3.73 mGy) at Centre A and B, respectively. The estimated median thyroid cancer risk was 2.88 × 10-6 (maximum range of 52 × 10-6) at centre A and a median value of 3.20 × 10-6 with a cancer risk estimate that may reach 17.9 × 10-6 recorded at centre B, compared to a cumulative thyroid cancer risk of 0.12 × 10-5 among the general Nigerian population. CONCLUSIONS: Scanner specifications and technique may significantly contribute to variations seen in thyroid radiation doses. There may be a need to optimise centre protocols and apply dose reference levels for head and neck CT examinations to reduce thyroid cancer risk in Nigeria.

Phenotyping Stroke in Sub-Saharan Africa: Stroke Investigative Research and Education Network (SIREN) Phenomics Protocol.

BACKGROUND: As the second leading cause of death and the leading cause of adult-onset disability, stroke is a major public health concern particularly pertinent in Sub-Saharan Africa (SSA), where nearly 80% of all global stroke mortalities occur, and stroke burden is projected to increase in the coming decades. However, traditional and emerging risk factors for stroke in SSA have not been well characterized, thus limiting efforts at curbing its devastating toll. The Stroke Investigative Research and Education Network (SIREN) project is aimed at comprehensively evaluating the key environmental and genomic risk factors for stroke (and its subtypes) in SSA while simultaneously building capacities in phenomics, biobanking, genomics, biostatistics, and bioinformatics for brain research. METHODS: SIREN is a transnational, multicentre, hospital and community-based study involving 3,000 cases and 3,000 controls recruited from 8 sites in Ghana and Nigeria. Cases will be hospital-based patients with first stroke within 10 days of onset in whom neurovascular imaging will be performed. Etiological and topographical stroke subtypes will be documented for all cases. Controls will be hospital- and community-based participants, matched to cases on the basis of gender, ethnicity, and age (±5 years). Information will be collected on known and proposed emerging risk factors for stroke. STUDY SIGNIFICANCE: SIREN is the largest study of stroke in Africa to date. It is anticipated that it will shed light on the phenotypic characteristics and risk factors of stroke and ultimately provide evidence base for strategic interventions to curtail the burgeoning burden of stroke on the sub-continent.

Clinical-radiological improvement following low-tech surgical treatment of an extensive cervical-medullary idiopathic syringomyelia in a low-resource African neurosurgical practice.

Surgical intervention is not so commonly deployed for idiopathic syringomyelia, even the symptomatic ones; is only undertaken, in the current era, after thorough clinical evaluation and extensive high-resolution neuroimaging; and is more assuredly performed, high-tech, in health facilities in the developed world with cutting edge logistic supports. In the practice environment of a low-resource African developing country, a 41-year-old young man recently presented in severe clinical-neurological deficit, Nurick grade 5, with an extensive cervical-medullary idiopathic syringomyelia. In spite of severe preoperative and intraoperative resource limitations, he successfully underwent spinal surgical decompression, fenestration of syrinx, and expansile duraplasty. He improved clinically postoperatively and achieved mobility, Nurick grade 3, before hospital discharge. He sustained this improvement, Nurick grade 3 to 2, 20 months post-op. He is now independent, needing only a walking stick to aid ambulation, and an MRI at this time showed only minimal focal post-op changes but total disappearance of the syrinx.

CT assessment of the nasolacrimal canal in a black African Population.

PURPOSE: Black Africans had been identified to have a lower prevalence of primary acquired nasolacrimal duct obstruction (PANDO). This has been attributed to the likely larger size of the nasolacrimal canal. However, there is paucity of studies that have quantitatively measured the dimension of the nasolacrimal canal in a homogeneous black population. The objective of this study was to determine the diameter of the bony nasolacrimal canal by CT in a normal adult Nigerian population. METHODS: The authors measured the minimum CT diameter of the bony nasolacrimal canal in 401 consecutive eligible adult patients using retrospective axial CT scans obtained between January 2006 and December 2010. The measurements were taken on axial images using a preset bone window algorithm on a standalone computer workstation with a ClearCanvas viewer (width: 2500, level: 480). The software calipers could measure up to a tenth of a millimeter. RESULTS: The CT images were made up of 378 cranial scans and 23 scans of paranasal sinuses. There were 286 male patients and 115 female patients aged 16 to 86 years with a mean age of 48.5 ± 18 years. The mean difference in nasolacrimal canal diameter of 3.52 mm in male patients and 3.36 mm in female patients was found to be statistically significant (t = 2.238, df = 400, p = 0.026). There was no significant difference in the canal diameter across age groups. In addition, there was no significant difference in the diameter between the right and left sides in the authors' study population (t = 1.551, df = 400, p = 0.122). CONCLUSIONS: The mean bony nasolacrimal canal diameter as measured by CT in Nigerians is smaller than those reported in African Americans, Asians, and Caucasians despite the reported lower prevalence of PANDO among blacks.

White matter changes on magnetic resonance imaging: a risk factor for stroke in an African population?

BACKGROUND: White matter changes are frequently observed incidental findings in elderly individuals. Many studies in Europe and the United States have assessed the association of white matter changes with stroke and other diseases. No similar study has been conducted in sub-Saharan Africa, where risk factors for stroke differ. Our objective was to explore the association between severity of white matter changes (based on visual rating scales) and stroke in a Nigerian population. METHODS: Magnetic resonance imaging (MRI) scans of 50 patients were retrospectively assessed and scored using 3 different visual rating scales (by Fazekas et al, Scheltens et al, and Manolio et al). The scores were classified as either mild or severe. Clinical indications and MRI scan results were classified into vascular (stroke) and nonvascular groups. The association between severity of white matter changes and stroke on MRI was explored using the Student t test, the Chi-square test, and multiple regression analysis at an alpha level of .05. RESULTS: White matter changes were consistently and significantly more severe in patients with stroke than in patients without stroke (.01 ≤ P < .001; odds ratios 4.58 and 13.3, respectively) using the 3 visual rating scales. This finding was independent of age and gender as confirmed by regression analysis (adjusted odds ratios 4.8 and 9.2; .015 ≤ P ≤ .003). CONCLUSIONS: Our findings suggest that severity of white matter changes in Nigerians may be a significant risk factor for stroke independent of age and gender. Prospective larger studies will be required to confirm its role in predicting stroke and stroke recurrence independent of other vascular risk factors, such as hypertension, diabetes, and cardiac diseases.

Risk Assessment Score and Chi-Square Automatic Interaction Detection Algorithm for Hypertension Among Africans: Models From the SIREN Study.

BACKGROUND: This study aimed to develop a risk-scoring model for hypertension among Africans. METHODS: In this study, 4413 stroke-free controls were used to develop the risk-scoring model for hypertension. Logistic regression models were applied to 13 risk factors. We randomly split the dataset into training and testing data at a ratio of 80:20. Constant and standardized weights were assigned to factors significantly associated with hypertension in the regression model to develop a probability risk score on a scale of 0 to 1 using a logistic regression model. The model accuracy was assessed to estimate the cutoff score for discriminating hypertensives. RESULTS: Mean age was 59.9±13.3 years, 56.0% were hypertensives, and 8 factors, including diabetes, age ≥65 years, higher waist circumference, (BMI) ≥30 kg/m2, lack of formal education, living in urban residence, family history of cardiovascular diseases, and dyslipidemia use were associated with hypertension. Cohen κ was maximal at ≥0.28, and a total probability risk score of ≥0.60 was adopted for both statistical weighting for risk quantification of hypertension in both datasets. The probability risk score presented a good performance-receiver operating characteristic: 64% (95% CI, 61.0-68.0), a sensitivity of 55.1%, specificity of 71.5%, positive predicted value of 70.9%, and negative predicted value of 55.8%, in the test dataset. Similarly, decision tree had a predictive accuracy of 67.7% (95% CI, 66.1-69.3) for the training set and 64.6% (95% CI, 61.0-68.0) for the testing dataset. CONCLUSIONS: The novel risk-scoring model discriminated hypertensives with good accuracy and will be helpful in the early identification of community-based Africans vulnerable to hypertension for its primary prevention.

Management of symptomatic vertebral haemangioma in a resource challenged environment.

INTRODUCTION: Vertebral haemangiomas are benign lesions and often asymptomatic. They are more common in the thoracic spine where they may become symptomatic with varying presentations. CASE REPORTS: We present two teenage girls who presented with progressive, nontraumatic paraparesis with no background history of chronic cough or underlying medical illness. DISCUSSION: The radiologic investigations were suggestive of vertebral haemangiomas of the thoracic spine. They had surgery: transthoracic approach with corpectomy and fusion with iliac crest autograft. The posterior stabilisation in the first patient was with Rush nails and circlage wire and only circlage wire in the second patient. The first patient's post-operative recovery was complicated by graft extrusion necessitating re-opening thoracotomy and graft replacement. They are, however, both ambulant at discharge and have remained so 13 and 15 months post-surgery. CONCLUSION: We have presented two cases with rewarding outcomes in the face of 'adaptive' instrumentation due to limited resources.

Abdominal ultrasonography in HIV/AIDS patients in southwestern Nigeria.

BACKGROUND: Though the major target of the HIV-virus is the immune system, the frequency of abdominal disorders in HIV/AIDS patients has been reported to be second only to pulmonary disease. These abdominal manifestations may be on the increase as the use of antiretroviral therapy has increased life expectancy and improved quality of life. Ultrasonography is an easy to perform, non invasive, inexpensive and safe imaging technique that is invaluable in Africa where AIDS is most prevalent and where sophisticated diagnostic tools are not readily available. PURPOSE: To describe the findings and evaluate the clinical utility of abdominal ultrasonography in HIV/AIDS patients in Ibadan, Nigeria METHODS: A Prospective evaluation of the abdominal ultrasonography of 391 HIV-positive patients as well as 391 age and sex-matched HIV-negative patients were carried out at the University College Hospital, Ibadan. RESULTS: Of the 391 cases studied, 260 (66.5%) were females; the mean age was 38.02 years, (range 15-66 years). The disease was most prevalent in the 4th decade with an incidence of 40.4%. Compared with the HIV-negative individuals, the HIV+ group of patients had a significantly higher proportion of splenomegaly (13.5% vs. 7.7%; p < 0.01), lymphadenopathy (2.0% vs. 1.3%; p < 0.70), and renal abnormalities (8.4% vs. 3.8%; p < 0.02). There were no differences in hepatic and pancreatic abnormalities between the HIV+ and HIV- groups. There were significantly fewer gallstones in the HIV+ group (1.4% vs. 5.1%; p < 0.01). CONCLUSION: AIDS is a multi-systemic disease and its demographic and clinical pattern remains the same globally. Ultrasonography is optimally suited for its clinical management especially in Africa. Its accuracy and sensitivity may be much improved with clinico-pathologic correlation which may not be readily available in developing countries; further studies may provide this much needed diagnostic algorithms.

Intraventricular cerebrospinal fluid pulsation artifacts on low-field magnetic resonance imaging: Potential pitfall in diagnosis?

BACKGROUND: Intraventricular cerebrospinal fluid (CSF) pulsation artifact can pose a diagnostic problem in fluid-attenuated inversion recovery (FLAIR) brain magnetic resonance images (MRI) appearing as intraventricular hyperintensity. The extent of this challenge among radiologists in Africa using low-field MRI systems is relatively sparsely documented in the literature. The purpose of this study was to identify the presence and frequency of ventricular CSF pulsation artifact (VCSFA) on FLAIR axial brain images with a low-field MR system. MATERIALS AND METHODS: FLAIR axial images were obtained on a low-field 0.3T unit (6000 ms/108 ms/2 [repetition time/echo time/excitations], inversion time = 1700 ms, field of view = 28 cm, matrix = 195 × 256, and 6 mm contiguous sections). Two experienced radiologists independently rated VCSFA in the lateral, third, and fourth ventricles in 202 consecutive patients (age range 1-100 years) referred for brain MR for various indications. We reviewed the pattern of artifacts, to determine its relationship to age, gender, and third ventricular size. RESULTS: The low-field FLAIR MR brain images of 33 patients (16.3%) showed VCSFA in at least one ventricular cavity. The fourth ventricle was the most common site of VCSFA (n = 10), followed by the third ventricle (n = 8) and the lateral ventricles (n = 7). Eight patients had VCSFA in multiple locations, one of them in all ventricles. A smaller third ventricular size and, to a lesser extent, younger age was significantly associated with VCSFA. CSF Pulsation of VCSFA did not occur across the brain parenchyma in the phase encoding direction. CONCLUSION: VCSFA may mimic pathology on low-field axial FLAIR brain images and are more common in young patients with smaller ventricular size. Although these artifacts are less frequently observed at lower magnetic field strengths, their recognition on low-field MRI systems is important in avoiding a misdiagnosis.

The Clinical Epidemiology of Spontaneous ICH in a Sub-Sahara African Country in the CT Scan Era: A Neurosurgical In-Hospital Cross-Sectional Survey.

BACKGROUND: There is paucity of data-driven scientific reports from sub-Saharan Africa on the burden of spontaneous intracerebral hemorrhage (sICH). We have maintained a prospective consecutive in-hospital database of cases of sICH referred for neurosurgical intervention over a 5-year period. METHODS: This is a cross-sectional descriptive study of the clinical epidemiology and brain computed tomography (CT) characterization of sICH from the database in this region in the current era. RESULTS: There were 63 subjects, 38 (60.3%) males, aged 28-85 years, mean 55.7 (SD, 12.7), the modal age distribution being the sixth decade. Uncontrolled hypertension was the main predisposition in the study: present, premorbid, in 79%, but uncontrolled in 88% of these known cases, and exhibited malignant derangements of blood pressure in more than half. The clinical ictus to in-hospital presentation was delayed, median 72 h; was in severe clinical state in 70%, 57% was comatose; and was complicated with fever in 57% and respiratory morbidity in 55.6%. The main clinical symptomatology was hemiparesis, headache, vomiting, and aphasia. The sICH was supratentorial on brain CT in 90.5%, ganglionic in 50.8%, and thalamic in 58.3% of the latter. The bleed had CT evidence of mass effect and intraventricular extension (IVH) in more than half. Twenty-three patients (36.5%) underwent operative interventions. CONCLUSION: In this patient population, sICH is mainly ganglionic and thalamic in location with significant rate of associated IVH. In-hospital clinical presentation is delayed, and in a critical state, the bleeding is uncontrolled hypertension related in >95%.

Role of Diffusion-weighted Imaging in Acute Stroke Management using Low-field Magnetic Resonance Imaging in Resource-limited Settings.

A variety of imaging modalities exist for the diagnosis of stroke. Several studies have been carried out to ascertain their contribution to the management of acute stroke and to compare the benefits and limitations of each modality. Diffusion-weighted imaging (DWI) has been described as the optimal imaging technique for diagnosing acute ischemic stroke, yet limited evidence is available on the value of DWI in the management of ischemic stroke with low-field magnetic resonance (MR) systems. Although high-field MR imaging (MRI) is desirable for DWI, low-field scanners provide an acceptable clinical compromise which is of importance to developing countries posed with the challenge of limited availability of high-field units. The purpose of this paper was to systematically review the literature on the usefulness of DWI in acute stroke management with low-field MRI scanners and present the experience in Nigeria.

Incidental cranial CT findings in head injury patients in a Nigerian tertiary hospital.

BACKGROUND: Incidental findings on computed tomography (CT) scans are occasionally noted in patients presenting with head injury. Since it can be assumed that head injured patients are of normal health status before the accident, these findings may be a representation of their frequency in the general population. Our aim was to determine the prevalence of such incidental findings among head injured patients in Nigeria's foremost center of clinical neurosciences. MATERIALS AND METHODS: We conducted a retrospective review of CT scan images of 591 consecutive eligible patients over a 5-year period (2006-2010) to identify incidental findings. The images were evaluated by consensus agreement of two radiologists. Associations with gender and age were explored using appropriate statistical tests with an alpha level of 0.05. RESULTS: The mean patient age was 34.6 ± 21.2 years, and male to female ratio was 3.2: 1. Incidental findings were noted in 503/591 (85.1 %) of the scans. Intracranial calcification was the commonest finding occurring in 61.8% of patients. Over 90% of the findings were benign. Compared with older ones, patients under the age of 60 were less likely, (P < 0.001), to have incidental findings. CONCLUSION: Although the majority of incidental findings in this African cohort of head injury patients are benign some clinically significant lesions were detectable. It is therefore recommended that such findings be adequately described in the radiological reports for proper counseling and follow-up.

ROLE OF TRANSCRANIAL COLOUR-CODED DUPLEX SONOGRAPHY IN STROKE MANAGEMENT - REVIEW ARTICLE.

The development of transcranial colour-coded duplex sonography (TCCS) has resurrected the hope of safe, real time bedside brain imaging beyond childhood. This review article provides an overview of the role of TCCS in the management of patients with stroke. The objective is to stimulate interest in the field of neurosonology as a potential means of improving neurological outcome for stroke patients and a area for stroke research endeavors in Africa. Literature search was done on MEDLINE, Cochrane library, and Google Scholar databases with the following keywords: transcranial colour Doppler, Transcranial duplex sonography, transcranial colour-coded Doppler sonography, stroke, infarct and haemorrhage. We also identified relevant articles from the references section of studies produced by our literature search. We discussed the roles of TCCS to discriminate ischaemic from haemorrhagic forms; unravel the mechanism of stroke; monitor temporal evolution of stroke and predictors of stroke outcome; and promote better understanding of the epidemiology of stroke. Its emerging role as a potent point-of-care imaging modality for definitive treatment in ischaemic stroke within and outside the hospital setting is also highlighted. Comparison of TCCS with alternative modalities for neuroimaging in stroke is also discussed. A root cause analysis of the untenable high cost of neuroimaging for stroke patients in Africa is presented vis-à-vis the potential economic relief which widespread adoption of TCCS may provide. We advocate capacity building for TCCS and suggest some action plans required to achieve safe, cheap, affordable and reliable ultrasound based neuroimaging for stroke patients in resource limited areas of Africa.

Comparative analysis of clinical and computed tomography features of basal skull fractures in head injury in southwestern Nigeria.

BACKGROUND: Basal skull fractures (BSF) in head injury may be missed clinically. Early detection ensures prompt treatment and prevention of complications We compared the clinical and Computed Tomography (CT) features of basal skull fractures in head injured patients in a southwestern Nigerian hospital. MATERIALS AND METHODS: Head injury patients who had cranial CT at a Southwestern Nigerian hospital were selected. CT images were acquired with a 64-slice Toshiba Aquillion CT scanner using a standard head protocol. The images were evaluated for evidence of skull fractures, and associated complications. The clinical data and CT findings were analyzed. RESULTS: One hundred and thirty patients were evaluated, including 103 (79.2%) males. Their ages ranged between 7 months and 81 years, mean 35 years (SD, 20.3). In 59 patients (45.4%, 59/130) BSF was detected on CT, while 71 (54.6%) had no evidence BSF. Forty-two (71.2%) of the 59 patients detected on CT had clinical suspicion of BSF (P < 0.001) while the remaining 17 (28.8%) were not clinically diagnosed. This equaled a sensitivity of 71.2% and, specificity of 90.1% for clinical determination of BSF in this study. There was no statistically significant difference between clinical and CT diagnosis (P > 0.05). The commonest observed clinical feature in patients with confirmed BSF was otorrhagia (45.8%) and the petrous temporal bone (45.8%) was the most commonly fractured bone. The BSF was caused most commonly by motor bike accidents in 53 (40.8%). The most common associated intracranial injuries were intracerebral haemorrhage (34.6%) and subdural (17.3%). CONCLUSION: It appears that neurosurgical evaluation is comparatively reliable in evaluating basal skull fractures in this study area even as they are consistently demonstrated by high resolution CT scanners. A clinical suspicion of BSF should warrant a closer detailed CT evaluation and reporting by radiologists.

Medial temporal lobe atrophy, white matter hyperintensities and cognitive impairment among Nigerian African stroke survivors.

BACKGROUND: Neuroimaging features associated with vascular cognitive impairment have not been examined in sub-Saharan Africans. We determined magnetic resonance imaging (MRI) features associated with cognitive impairment in a sample of Nigerian stroke survivors. METHODS: Stroke survivors underwent brain MRI with standardized assessment of brain volumes and visual rating of medial temporal lobe atrophy (MTA), and white matter hyperintensities (WMH) at 3 months post-stroke. Demographic, clinical and psychometric assessments of global cognitive function, executive function, mental speed and memory were related to changes in structural MRI. RESULTS: In our pilot sample of 58 stroke survivors (60.1 ± 10.7 years old) MTA correlated significantly with age (r = 0.525), WMH (r = 0.461), memory (r = -0.702), executive function (r = -0.369) and general cognitive performance (r = -0.378). On univariate analysis, age >60 years (p = 0.016), low educational attainment (p < 0.001 to p < 0.003), total brain volume (p < 0.024 and p < 0.025) and MTA (p < 0.003 to p < 0.007) but not total WMH (p < 0.073, p = 0.610) were associated with cognitive outcome. In a two-step multivariate regression analysis, MTA (p < 0.035 and p < 0.016) and low educational attainment (p < 0.012 and p < 0.019) were sustained as independent statistical predictors of cognitive outcome. CONCLUSIONS: Medial temporal lobe atrophy was a significant neuroimaging predictor of early post-stroke cognitive dysfunction in the Nigerian African stroke survivors. These observations have implications for a vascular basis of MTA in older stroke survivors among sub-Saharan Africans.

Testicular tuberculosis presenting with metastatic intracranial tuberculomas only: a case report.

INTRODUCTION: Intracranial tuberculomas are a rare complication of tuberculosis occurring through hematogenous spread from an extracranial source, most often of pulmonary origin. Testicular tuberculosis with only intracranial spread is an even rarer finding and to the best of our knowledge, has not been reported in the literature. Clinical suspicion or recognition and prompt diagnosis are important because early treatment can prevent patient deterioration and lead to clinical improvement. CASE PRESENTATION: We present the case of a 51-year-old African man with testicular tuberculosis and multiple intracranial tuberculomas who was initially managed for testicular cancer with intracranial metastasis. He had undergone left radical orchidectomy, but subsequently developed hemiparesis and lost consciousness. Following histopathological confirmation of the postoperative sample as chronic granulomatous infection due to tuberculosis, he sustained significant clinical improvement with antituberculous therapy, recovered fully and was discharged at two weeks post-treatment. CONCLUSION: The clinical presentation of intracranial tuberculomas from an extracranial source is protean, and delayed diagnosis could have devastating consequences. The need to have a high index of suspicion is important, since neuroimaging features may not be pathognomonic.

Internal jugular phlebectasia in an African adult.

Jugular vein phlebectasia is a rare venous anomaly commonly presenting as a unilateral neck swelling in children and adults. Its aetiology is unknown and its detection may have increased with availability of better imaging facilities. Due to its rarity, a high index of suspicion is required once other causes of neck swelling are excluded. The few reported cases are mainly in children and non-Africans adults. The authors report the case of a 54-year-old Nigerian woman presenting for the first time with a progressive, intermittent, painless right neck swelling, which was demonstrated on Doppler ultrasound and CT angiography to be an internal jugular phlebectasia. She had satisfactory surgical excision of the dilated segment for cosmetic reasons.