Mark Soo

Chordoma: Review of clinicoradiological features and factors affecting survival

This study reviews the clinicoradiological features of cranial and sacrospinal chordomas and identifies factors affecting survival. Nineteen patients seen between January 1980 and December 2000 with histopathological diagnosis of chordomas were retrospectively reviewed with reference to clinical presentation, imaging features, treatment modalities and post-therapy status. Eight had tumours in the skull base while 11 patients had spinal and sacrococcygeal lesions. Surgical resection was performed in 16 patients whose subsequent natural history was used to identify clinical indicators that may influence survival. Completeness of resection, age, gender and postoperative irradiation were subjected to analysis using the Cox proportional hazard models. Kaplan-Meir survival curves illustrate the survival distributions. Diplopia and facial pain are prime clinical presentations in cranial lesions, while extremity weakness and a sacrogluteal mass are common complaints in the sacrospinal group. Lesional calcifications are present in 40% while an osteolytic soft tissue mass is detectable by CT in all cases. Heterogeneous signals and internal septations on T2-weighted MRI are predominant features. In sacrospinal tumours, complete excision with adjuvant radiotherapy achieves the best results with a disease-free survival of more than 5 years. The clinical and imaging findings in this study are in accordance with those of other series. Except for complete surgical excision followed by radiotherapy in the subset of patients with sacrospinal tumours, none of the other clinical indicators show a statistical significant influence on survival.

Spiral CT Scanning in the Detection and Evaluation of Aneurysms of the Circle of Willis

PURPOSE To assess the utility of spiral computed tomography (CT) with three-dimensional reconstruction in defining aneurysms of the Circle of Willis. METHODS Eighty-one patients with angiographic or surgical correlation were studied between 1993 and 1995, with surface rendered reconstructions of the arteries of the Circle of Willis. RESULTS Spiral CT was useful in six clinical situations: further assessment in cases with CT suspicion of an aneurysm, follow-up of known untreated aneurysms or aneurysm remnants, subarachnoid hemorrhage (SAH) with negative angiography, a past or family history of aneurysms, and improved definition of aneurysm anatomy. Ten of fifteen patients with previous surgery had no significant artifacts on the spiral study. In 66 other patients studied in search of aneurysms, the sensitivity of detection was 95% and specificity 74%. Seventeen of nineteen aneurysms 3 mm or less in size and 38 of 39 larger were detected by spiral CT. Four of thirteen patients with SAH and previous negative angiography had aneurysms identified, which were confirmed at surgery. CONCLUSIONS There is great promise in the use of spiral CT in demonstrating aneurysms of the Circle of Willis, including very small ones. Careful detailing of scan protocols and meticulous examination of multiplanar images are needed for maximum accuracy.

Ossification of the posterior longitudinal ligament of the cervical spine

Although ossification of the posterior longitudinal ligament (OPLL) of the cervical spine is an uncommon condition, its strong prevalence among the Japanese and non-Japanese Asians is well known. Genetic predisposition coupled with ageing and an imbalance in bone-seeking hormones are some actiological factors postulated in recent years. Imaging is directed at showing the calcified mass, cord compression and any attendant damage, as the latter are important prognostic factors. We describe 6 cases of OPLL of the cervical spine seen at Westmead Hospital between 1979 and 1994. Of the 4 patients presenting with disabling compressive myelopathy, 3 made significant recovery following surgical decompression. Characteristic plain film features manifesting as a dense calcified linear structure along the course of the posterior longitudinal ligament (PLL) were present in 5 patients, including 1 who was asymptomatic. Computed tomography (CT) was invaluable in demonstrating the full extent of the disease in all 5 symptomatic patients. Magnetic resonance imaging (MRI) was helpful in excluding myelomalacia in 2 patients prior to successful surgery. The myelopathy caused by cervical OPLL remains rare, affecting mainly middle aged males of Asiatic and European extraction.

Solitary intracranial plasmacytoma

Abstract Solitary intracranial plasmacytomas (SIPs) are rare tumours that may be mistaken radiologically for meningiomas. According to the literature, the predominant feature on polytomography and computed tomography (CT) is a bone-eroding, contrast-enhancing soft tissue mass, part of which might have extended extracranially before initial presentation. The lesions can be solitary and are therefore amenable to surgical excision. Although no recurrence is seen for up to 10 years after treatment, some authors believe progression to multiple myeloma is inevitable. Lesions that are extramedullary in origin are thought to have the best prognosis. We describe three cases treated surgically at Westmead Hospital in the past 6 years. All had CT features similar to those reported previously. On magnetic resonance imaging, which in this condition has not been fully documented, the lesions were slightly hyperintense with the brain on T1-weighted sequences, and were inhomogeneous and hyperintense with T2-weighted images. The two patients who received intravenous contrast showed dense and uniform enhancement. Occasional intralesional signal voids suggested increased vascularity, which was confirmed surgically. The presence of intracellular immunoglobulins may account for the hyperintensity on T2 sequence. Although no specific imaging features were identified to distinguish meningiomas from SIP, the latter should be included in the differential diagnosis of solitary bone eroding intracranial tumours.

Computed tomography and magnetic resonance imaging of the brain in hypoglycaemic encephalopathy

A diabetic man suffering from a hypoglycaemic attack presented to our hospital. Magnetic resonance imaging (MRI) findings were grossly abnormal and difficult to interpret. The computed tomographic appearance simulated multiple infarctions. The MRI appearance simulated a space occupying lesion. Literature review of the radiology and the pathophysiology of hypoglycaemic brain damage is provided. Comparison between our findings and previous reports is also given.

Cervical chordoma: case report

Chordomas of the cervical spine are rare. A case of a cervical chordoma is described. The initial radiological misinterpretation was due to the unavailability of CT myelography or MRI. Treatment of this disease is difficult, with multiple operations often required. Tumour bulk at diagnosis, completeness of surgical excision, availability of radiotherapy and biological behaviour of the chordoma are the main determinants of survival. Our case is interesting in terms of long survival which is 11 years to date. On reviewing the recent literature we have not found separate survival statistics for cervical chordoma, however, we have found 4 other cases of cervical chordoma with survival greater than 10 years.