ABSTRACT
In previous studies the origin of the majority of isolated sixth nerve palsies was not clear or was ascribed to vascular disease. Our purpose was determine how frequently a causative lesion was demonstrated on MRI in patients with an acute unilateral sixth nerve palsy. We performed a prospective study of 43 patients using a standardised protocol. In 27 patients (63%) a lesion was identified on the initial MRI relevant to the sixth nerve palsy; 21 (49%) were found to have a tumour or tumour-like lesion; the frequency of presumed vasculopathy in this group was 15%. There were 16 patients (37%) with an initially normal MRI, of whom 10 (62%) had a history of vasculopathy, a significantly different proportion from the group of patients with a visible causative lesion. MRI after 3-6 months was normal in all patients with a normal initial MRI. We suggest that MRI should routinely be performed in patients presenting with an acute sixth nerve palsy, even those with evidence of a vasculopathy. If the symptoms regress spontaneously and there is a history of vasculopathy, follow-up MRI is not necessary.
Subject(s)
Abducens Nerve Diseases/diagnosis , Abducens Nerve/pathology , Magnetic Resonance Imaging , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Prospective StudiesABSTRACT
High temporal and spatial resolution has recently been achieved by rapid magnetic resonance imaging techniques. This offers the opportunity to perform dynamic magnetic resonance imaging in addition to topographic imaging and tissue analysis. Using sequences obtained by turbo-fast low-angle shot imaging we have reduced temporal resolution to 1 s per image.
Subject(s)
Magnetic Resonance Imaging/methods , Ocular Motility Disorders/diagnosis , Orbital Diseases/diagnosis , Adult , Aged , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Ocular Motility Disorders/etiology , Orbital Diseases/etiology , Sensitivity and SpecificityABSTRACT
The variability of the interpretation of visual fields by physicians has so far been thoroughly examined only with reference to light sense perimetry. Therefore, we studied the variability in assigning visual fields to topical diagnoses of the visual pathway with the ring perimeter. For this purpose we examined the proportion of correct assignments of physicians and the reproducibility of their assignments. Two experienced ophthalmologists had to assign 76 selected pairs of right and left visual fields to one of the following diagnosis without any information about further clinical findings: (1) normal (n = 5), (2) media opacity (n = 5), (3) retinal lesion (n = 5), (4) optic disc lesion (n = 6), (5) optic nerve lesion (n = 6), (6) lesion of the chiasma (n = 5) and (7) retrochiasmal lesion (n = 6). The assignment was repeated after intervals of 6 weeks and 10 months. Our statistical analysis of the number of correct assignments revealed no significant differences between the perimeters or between the physicians. The amount of correct assignments with both perimeters decreased from 75% and 66% during the first run through 60% and 70% during the second run to 58% and 60% during the third. Neither perimeter showed any major differences in the reproducibility of the assignments (Fig. 4). During the three runs only 47% (physician 1) and 58% (physician 2) of the cases were assigned three times to the same diagnoses with the octopus. The corresponding figures for the ring perimeter were 58% and 60%. This is regarded as an indicator of the unreliability in the interpretation of visual fields.
