Degree of midline shift from CT scan predicted outcome in patients with head injuries.

OBJECTIVE: To evaluate the relationship between the degree of midline shift by Computed Tomography (CT) finding and Glasglow Coma Score (GCS) as a predictive of clinical outcome in patients after head injury. METHOD AND METHOD: The present study was performed by retrospectively reviewing 216 consecutive cases of traumatic head injury admitted to the trauma center in Siriraj Hospital from 1999 until 2004. All patients were evaluated for level of consciousness by a neurosurgeon determining by GCS and underwent CT brain for evaluation of intracranial hemorrhage and midline shift. The final clinical outcome was also divided into two groups; good outcome for the patients who recovered well with moderate disability and the poor outcome for the patients who suffered severe disability, vegetative status and death. Then, the authors compared midline shift vs. GCS and midline shift vs. clinical outcomes. RESULTS: Total of 216 cases, the three most common types of head injury were motorcycle accident, fall or assault and car accident. 96 of 216 patients had midline shifting, 53 of 96 patients had CT scan of midline shifting less than 10 mm whereas 37 of 96 patients had a CT scan of greater than 10 mm of midline shifting. 63.3% with midline shifting up to 10 mm had severe head injury and up to 81% with brain shifting greater than 10 mm had severe head injury. The clinical outcome also showed that poor clinical outcomes correlated to midline shifting greater than 10 mm. CONCLUSION: The increased degree of midline shift in patients with head injuries by CT scan was related to the severity of head injury (GCS = 3-12) and was significantly related to poor final clinical outcome.

Evaluation of image quality and lens's radiation dose of a low-dose cranial CT scan.

OBJECTIVE: To determine the lowest miliampere-second (mAs) of a cranial computed tomography (CT) scan that can maintain acceptable image quality on cranial CT scan which might help reducing the risk of cataract formation. MATERIAL AND METHOD: The present study was performed on the 148 patients in routine daily practice sent for diagnosis of intracranial conditions by a cranial CT scan. During the cranial CT scanning, each lens's radiation dose on patient's eyes was measured by a thermoluminescent dosimeter Clinical image quality, particularly in analysis of gray and white matter differentiation, was evaluated independently using a 5 point scale by two radiologists. RESULTS: During standard cranial CT scan protocol with 250 miliampere-second (mAs), the total dose of left and right lens's dose were about 50.93 miligray (mGy) and 51.66 mGy, respectively. When applying low dose cranial CT scan protocols by decreasing mAs to 200, 150 and 100 mAs, the total dose ofright and left lens were of 45.68 mGy and 46.04 mGy for 200 mAs, 34.65 mGy and 34.77 mGy for 150 mAs, 28.73 mGy and 29.25 mGy for 100 mAs respectively. CONCLUSION: A low dose cranial CT scan at 100 miliampere-second provides not only an acceptable clinical image quality, but also decreases the lens's radiation dose by 43%.