Diagnostic accuracy of perfusion CT in differentiating brain abscess from necrotic tumor.

OBJECTIVE: To evaluate the diagnostic accuracy of perfusion computed tomography (CTP) in differentiating between brain abscess and necrotic tumor. MATERIAL AND METHOD: Prospective study was performed in patients suspected of a space taking lesion in the brain. CTP was done at the suspected levels and post-processing measurement of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and permeability surface index (PS) were evaluated at ring enhanced area, central non-enhanced area, edema and contralateral normal brain. RESULTS: Seventeen patients with 21 lesions were studied. Of the 21 lesions, 12 were abscess and nine were tumors. By comparing means, only MTT at the ring enhanced area showed statistically significant difference between brain abscess and tumor (p = 0.009, 95% CI = 1.403 to 4.900). When ratio of CBV, CBF and MTT of the ring enhanced area and contralateral normal brain were analyzed (CBVr, CBFr, MTTr respectively), there were significant differences of CBVr and CBFr between the two groups (p = 0.003, 95% CI = -4.266 to -1.051 and p = 0.006, 95% CI = -9.934 to -1.969 respectively). With the threshold of CBVr more than or equal to 1.5 and CBFr more than or equal to 1, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosis of tumor were 100%, 75%, 75%, 100%, and 85.7% respectively. CONCLUSION: The CTP was shown to be useful in differentiating brain abscess from tumor. With CBVr less than 1.5, tumor can be excluded.

Combined surgery and endovascular treatment of complicated traumatic carotid-cavernous fistulas: Results and illustrated cases.

Objective: To review Siriraj Hospital’s experiences with direct surgical treatment of complicated traumatic carotid-cavernous fistulas (CCFs) in the context of multidisciplinary approach. Methods: This study is a retrospective review of complicated direct carotid cavernous fistulas (CCFs) that had opened surgery after failure of detachable balloon embolization. Data were collected from medical records, radio-angiographic records, and follow-up results of combinations of treatment. Results: From 1993- April 2003, we have total 25 cases of combined surgery and endovascular treatment of traumatic carotid-cavernous fistulas (CCFs). Causes of unsuccessful balloon embolization are small-hole fistula, deflation of the balloon, difficult position of fistula, false aneurysm, risk of intracavernous internal carotid artery (ICA) occlusion, and tortuosity of ICA and draining veins. Various procedures were performed and all patients have good results with completed resolution of clinical triad symptoms. On follow-up cerebral angiography of 16 patients that received cavernous sinus packing, we could preserve the patency of ICA in 8 patients but 5 patients had thrombosis of ICA without ischemic events. In 3 patients, an operation to occlude the ICA was performed after failure of cavernus sinus packing. Conclusions: The standard treatment of carotid cavernous fistula is endovascular balloon embolization. When the endovascular treatment fails, surgical packing of cavernous sinus is immediately considered an alternative way to cure the CCFs and to offer additional technique to help increase the patency of ICA.

Expression of cyclooxygenase-1 and -2 in cultured human glioma cells of various stages.

Cyclooxygenase-1 (COX-1) and -2 (COX-2) are two isoforms of enzymes responsible for the biosynthesis of several forms of prostaglandins (PGs) from arachidonic acid. COX-1 is constitutively expressed in most normal tissues while COX-2 expression is regulated by certain stimuli such as cytokines and growth factors. The expression of COX-2 has been associated with many pathological conditions such as atherosclerosis, inflammation, and cancers (e.g. colon, breast, and lung cancers). COX-2 expression may be associated with the progression of cancers since PGE2, a major product of both isoforms was identified as a tumor-derived immune suppressor. Therefore, the suppression of COX-2 activity using specific COX-2 inhibitors (recently classified non-steroidal anti-inflammatory drugs) may delay the progression of tumors harboring COX-2. The search for tumors that highly express both isoforms of COX serves as a guide to target tumors that are most likely to be susceptible to treatment with specific COX-2 inhibitors. To study a homogeneous population of tumor cells, fifteen samples of primary culture cells were prepared from different human brain tissues and tumors collected from subjects operated on at Siriraj Hospital. Cells were grown to confluent in 75-cm2 tissue culture flask for about 4 weeks. After which time, cells were extracted to evaluate COX-1 and COX-2 protein expressions by immunoblot using specific antibodies. Four out of seven samples of glioblastoma multiforme cells strongly expressed COX-2, while all samples of examined cultured cells expressed COX-1. Cultured cells from astrocytomas had only faint staining for COX-2, while maintaining strong COX-1 expression. Thus COX-2 expression was limited to samples of glioblastoma multiforme, the most advanced stage of astrocytoma. Further study for the suppression of COX-2 activity in inducing tumor apoptosis and in improving cellular immunity against this advanced cancer should be elucidated.

Skull base surgery: Access to anterior and middle cranial fossa.

Although skull base lesions, which differ in comparison to other areas of pathology, are difficult to deal with, much has been published of the subject in the last two decades. Access, visualization, surgical skill, and technique are keys of surgical success. Since June 1995 – December 1996, 47 cases were performed by the basal skull group; (neurosurgeon, ENT, ophthalmic and plastic surgeons). Among these cases, 28 fronto-orbito-zygotomies were performed for anterior and middle cranial fossa lesions including tumors of the cavernous sinus, vascular aneurysms and orbital tumours, etc. Most benign lesions were totally removed and functional preservation was achieved in most cases. Only one case of morbidity from injury to the frontal nerve and two mortalities from intracerebellar haemorrage and sepsis occurred. Access is the major crucial factor which can determine the functional result, and involvement of multidisciplinary fields will provide good cosmetic results.