Previous CT Scan Research Articles

Early invasive CNS aspergillosis

A 46-year-old woman with non-Hodgkin's lymphoma presented with a new onset of seizures. A cranial CT was interpreted as normal. Eight months later, she presented with changed mental status and leg weakness, and a repeat CT scan showed multiple ring-enhancing lesions close to the left frontal sinus, with mass effect. A review of the previous CT scan showed a very small area of sinusitis as well as a small ring-enhancing lesion contiguous to it. A short course of intravenous steroids markedly relieved her symptoms, and a stereotactic biopsy confirmed Aspergillus fumigatus to be the cause of the infection. She was successfully treated with Amphotericin B. Central nervous system (CNS) aspergillosis is a potentially fatal disease. The therapeutic success in this case was related to a high index of suspicion at her second presentation. As the early signs of infection might be subtle and easily missed, patients at high risk for opportunistic infection should be studied carefully when new onset of CNS symptoms occur. Early initiation of therapy should improve the prognosis in such cases.

Description of brain injury in the amnesic patient N.A. Based on magnetic resonance imaging

N.A. has been amnesic since 1960 when at the age of 22 years he sustained a penetrating brain injury with a miniature fencing foil. The amnesia primarily affects verbal material and occurs in the absence of other detectable cognitive deficits. Previous CT scans demonstrated a lucency in the region of the left mediodorsal thalamic nucleus, but no additional damage was revealed. Beginning in 1986 when he was 48 years old, N.A. was evaluated with a series of magnetic resonance imaging (MR) studies. Three major areas of damage were identified. In the left thalamus there is a prominent 3- to 4-mm-wide linear lesion that approximates the position and orientation of the internal medullary lamina. The defect extends for approximately 20 mm anteroposteriorly and likely involves the rostral group of intralaminar nuclei (central medial, paracentral, central lateral, rhomboid, and reuniens nuclei), the caudal group of intralaminar nuclei (centrum medianum and parafascicular nuclei), the ventral aspects of the mediodorsal nucleus, and the ventral lateral and ventral anterior nuclei. It also likely interrupts the trajectories of the mammillothalamic tract and postcommissural fornix. The posterior hypothalamus is markedly disrupted and the mammillary nuclei appear to be missing bilaterally. Finally, the right anterior temporal lobe is damaged for a distance of about 3.5 cm from the pole to midway through the amygdaloid complex. This damage probably occurred during exploratory neurosurgery done at the time of N.A.'s injury. The hippocampal formation appears intact on both sides. A comparison of these findings with those from other patients with diencephalic amnesia suggests that amnesia can result when several diencephalic structures are damaged conjointly, including the internal medullary lamina, the intralaminar nuclei, the mediodorsal nucleus, and the mammillothalamic tract. Whether amnesia as severe as N.A.'s would result from selective damage to any one of these structures remains to be determined.

Occult Plastic Intraocular Foreign Body

A 34-year-old man was evaluated for posttraumatic endophthalmitis with hypopyon. A previous CT scan of the orbit along with B-scan ultrasonogram failed to confirm the presence of an intraocular foreign body. Nevertheless, at the time of vitrectomy, a polyvinyl chloride (PVC) plastic foreign body was encountered. The atypical posttraumatic uveitis that developed was apparently secondary to the PVC material, as the inflammation cleared rapidly following removal of the foreign body. This case illustrates the necessity for maintaining a high level of suspicion for the possibility of an intraocular foreign body in the event of ocular trauma, even in the presence of unconfirming ancillary tests.

MR imaging of schizencephaly.

MR imaging was used to evaluate six patients who had schizencephaly, a disorder of cell migration characterized by holohemispheric, gray-matter-lined clefts. Clinically, these patients presented with intractable seizures and variable developmental delay. Although three of these patients had previous CT scans, the diagnosis was made only by MR. MR was more sensitive than CT in detecting the clefts as well as the accompanying abnormalities, including areas of pachygyria, polymicrogyria, and heterotopic gray matter. The possible pathogenesis of schizencephaly is discussed. MR provides excellent demonstration of the anatomic changes in schizencephaly.

Computed tomographic scans in ECT-patients.

Although the safety and efficacy of electroconvulsive therapy (ECT) is acknowledged by most, concern has repeatedly been expressed that the treatment may have some lasting effects on the brain. To study potential morphological changes, 22 patients with a history of ECT were submitted to a detailed clinical evaluation and a brain CT scan examination. Age- and sex-matched control subjects comprised a group of comparable patients, none of whom had received ECT, and a second control group of healthy volunteers. Patients had larger ventricle/brain ratios and cortical "atrophy" scores than normal controls, but no association was found between these radiological measures and a previous history of ECT. Hence, the present data are consistent with recent reports that affective disorders may be associated with enlarged brain ventricles, although the clinical significance of such findings remains unclear. In line with previous investigations age correlated significantly with cortical "atrophy" scores and ventricle/brain ratios for all subjects. Statistical tests of correlations between duration of illness, previous psychotropic drug exposure and CT scan appearances were mainly inconclusive.

Ocular biometry using computed tomography: A study in Benin, Nigeria

AIMS AND OBJECTIVES The aim was to determine CT measured ocular biometry in Mid-Western Nigeria which may be employed on other Nigerians and Black Africans. PATIENTS AND METHODS The ocular images of 200 patients that had normal cranial CT scans without ocular abnormality or complaints were retrospectively retrieved and analysed. The CT scans were done at the University of Benin Teaching Hospital. The axial length and width were obtained at the maximum mid-axial images and analysed using SPSS version 17 for measures of central tendency and correlations between variables (level of significance set at 0.05). RESULTS The mean axial length was 21.4mm (right) and 21.6mm (left) while the width was 21.6mm (for right and left). The ocular biometry was larger in the left eye than the right, and also in males than females. The axial length and width increased with advancing age. CONCLUSION CT ocular biometry can be performed on previous cranial CT scans done for other reasons. The dimensions in this study may be used as a local normogram.