One hundred computerized tomography (CT) scans from patients with rhinosinusitis were compared with 100 CT scans from patients with intraorbital disease. There were no significant bony anatomical differences between the rhinosinusitis group and the control group and there remained no difference when 17% of the control group, who were incidentally found to have mucosal changes, were excluded from the control data. None of the anatomical bony variations compared between the two groups showed any significant difference, including any associated with narrowing of the ostiomeatal complex (P = 0.41). Eight per cent of all subjects (n = 200) had Onodi cells and 7% had an asymmetrical anterior skull base. In conclusion, bony anatomical variations appear not to influence the prevalence of rhinosinusitis. Intrinsic mucosal disease is probably of much more importance than the bony anatomy.

Five angiographically confirmed cases of ectasia of the basilar artery are described. Three patients presented with the classical combination of lower cranial nerve, bulbar, cerebellar and long tract signs and dementia, one as obstructive hydrocephalus with papilloedema, and the fifth with symptoms of chiasmal compression. All were above middle age and hypertensive. CT scanning demonstrated a partially calcified, tubular, enhancing prepontine and suprasellar mass in every case. Ventricular enlargement and cerebral parenchymal abnormalities were also present. These appearances are sufficiently characteristic to make invasive radiological investigation unnecessary.

A review was performed of the computed tomograms (CTs) of 500 children which had been reported as showing widening of the supratentorial subarachnoid spaces with normal cerebral substance. On the basis of this a radiological diagnosis of cerebral atrophy had been made in all but five, who were said to have megalencephaly. From these, the children with large or abnormally enlarging heads, but normal or only slightly enlarged ventricles, were selected; there were 40 such cases (8%). The clinical condition either improved or remained stable over a period of 2 years; in the majority the scan abnormality regressed (22.5%) or remained static (67.5%). In three cases there was slight progression of the CT changes before stabilisation, but only one case developed classical communicating hydrocephalus necessitating a shunt procedure. This condition is a generally benign and mild form of communicating hydrocephalus, for which an aetiological factor was apparent in about two-thirds of the cases studied.

Computed tomography (CT) provides an excellent map for the sinus surgeon aswell as providing information about the extent of disease and the presence of bony destruction. Surgeons need to be aware of the anatomical configuration of the sinuses and the presence of any structural changes such as a dehiscent lamina papyracea, asymmetric skull base, low level of posterior skull base or an Onodi cell, which place the patient at increased risk. Described here is a six-step guide to help the sinus surgeon avoid missing any of the radiologically important features.