Adenoid measurement accuracy: A comparison of lateral skull film, flexible endoscopy, and intraoperative rigid endoscopy (gold standard).

OBJECTIVE: To compare the accuracy of lateral skull film, flexible endoscopy, and intraoperative rigid endoscopy in assessment of adenoid size. METHODS: A cross-sectional study was conducted in 43 pediatric patients undergoing ENT surgery from July 2017 to December 2018. All patients underwent preoperative lateral skull film, flexible endoscopy, and intraoperative rigid endoscopy. RESULTS: The average adenoidal-nasopharyngeal (A/N) ratio obtained from lateral skull film, flexible endoscopy, and intraoperative rigid endoscopy was 72.9, 79.5, and 81.6, respectively. There was a moderate correlation between A/N ratio from lateral skull film and intraoperative rigid endoscopy (Pearson's correlation: 0.567, p˂0.001). Whereas, the A/N ratio from flexible endoscopy compared to intraoperative rigid endoscopy showed a stronger correlation (Pearson's correlation: 0.791, p˂0.001). From linear regression analysis, the intraoperative adenoid measurement was estimated from the results of flexible endoscopy (intraoperative rigid endoscopy: 0.72 [flexible endoscopy] +24.47) and lateral skull film (intraoperative rigid endoscopy = 0.65 [lateral skull film] + 34) CONCLUSION: Flexible endoscopy yields the most accuracy in the assessment of adenoid size and nasopharynx visualization, without radiation exposure or anesthesia. Despite less accuracy, lateral skull film is more availability in every hospital. The correlation of adenoid size measurement in this study can also be applied for the actual size of adenoid.

Computerized Tomographic Angiography for Detection of Cerebral Vasospasm after Ruptured Intracranial Aneurysm.

OBJECTIVE: Digital subtraction angiography (DSA) is the gold standard to diagnose cerebral vasospasm but it is usually not available due to lack of expertise and proper equipment. The present study aimed to compare the diagnostic accuracy of brain computerized tomographic angiography (CTA) in detecting cerebral vasospasm after intracranial aneurysmal rupture. MATERIAL AND METHOD: Between January 2011 and October 2014, 20 patients who were suspected of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) were prospectively enrolled. All patients underwent brain CTA andDSA within 24 hours after clinical onset ofvasospasm. Separate reviewers independently reviewed the CTA and DSA. RESULTS: Twenty patients were enrolled, including 7 males and 13 females. The patient characteristics did not have any relationship to the incidence of cerebral vasospasm. The CTA finding of vasospasm was well correlated to the DSA finding (Kappa 0.793). Diagnostic accuracy and false negative of the CTA were 90% and 5%, respectively. Sensitivity of the CTA was 94% and specificity was 100%. Positive predictive value ofthe CTA was 100% and negative predictive value was 66%. The vessels that showed the most correlation between the CTA and DSA findings were left A1 (Kappa 0.684) and left A2 (Kappa 0.663) segments of anterior cerebral artery, and left M1 (Kappa 0.503) segment of middle cerebral artery. Both CTA and DSA can detect mild vasospasm (< 50% luminal stenosis) located proximal to the circle of Willis. CONCLUSION: Compared to the DSA, the CTA can be used for detecting cerebral vasospasm in patients with ruptured intracranial aneurysms with high sensitivity, specificity, and diagnostic accuracy.

Metal artifact reduction and image quality evaluation of lumbar spine CT images using metal sinogram segmentation.

Metal artifacts often appear in the images of computed tomography (CT) imaging. In the case of lumbar spine CT images, artifacts disturb the images of critical organs. These artifacts can affect the diagnosis, treatment, and follow up care of the patient. One approach to metal artifact reduction is the sinogram completion method. A mixed-variable thresholding (MixVT) technique to identify the suitable metal sinogram is proposed. This technique consists of four steps: 1) identify the metal objects in the image by using k-mean clustering with the soft cluster assignment, 2) transform the image by separating it into two sinograms, one of which is the sinogram of the metal object, with the surrounding tissue shown in the second sinogram. The boundary of the metal sinogram is then found by the MixVT technique, 3) estimate the new value of the missing data in the metal sinogram by linear interpolation from the surrounding tissue sinogram, 4) reconstruct a modified sinogram by using filtered back-projection and complete the image by adding back the image of the metal object into the reconstructed image to form the complete image. The quantitative and clinical image quality evaluation of our proposed technique demonstrated a significant improvement in image clarity and detail, which enhances the effectiveness of diagnosis and treatment.

Diagnostic performance of advanced MRI in differentiating high-grade from low-grade gliomas in a setting of routine service.

OBJECTIVE: To evaluate the usefulness of advanced MRI techniques in differentiating high-grade (HGG) from low-grade gliomas (LGG). MATERIAL AND METHOD: Sixty-four patients with suspected gliomas were prospectively evaluated by conventional and advanced MRI studies including MR spectroscopy (MRS), diffusion tensor imagining (DTI), and dynamic susceptibility contrast (DSC) MRI. The parametric measurements of metabolic profile, cerebral blood volume, flow (CBV, CBF), apparent diffusion coefficient (ADC), fractional anisotropy, and their ratios by internal normalization were analyzed to differentiate LGG from HGG. Histopathologic findings were used as the gold standard. RESULTS: Forty-three cases with pathologically-proven gliomas were included The best discriminating features between HGG and LGG were CBV and CBF of the solid tumoral region (p < 0.05) whereas the minADC/corpus callosum ratio for DTI and the ratio of Cho/Cr for MRS of the solid tumoral region provided the best diagnostic performance (p < 0.05). With a predetermined threshold for each parametric measurement, the combination of all advanced MRI modalities was associated with the best accuracy whereas the combination of DSC MRI and MRS provided the highest specificity. When all parametric measurements were positive, the probability of HGG was 0.889. CONCLUSION: Comprehensive advanced MRI studies provided better diagnostic performance than using conventional MRI alone in the evaluation of gliomas.

Diagnostic performance of perfusion MRI in differentiating low-grade and high-grade gliomas: advanced MRI in glioma, A Siriraj project.

BACKGROUND: To determine the usefulness of the perfusion MRI technique at Siriraj Hospital for differentiating between high- and low-grade gliomas by using pathological results as the gold standard. MATERIAL AND METHOD: The authors prospectively investigated 64 consecutive patients who were suspected as cerebral glioma from prior conventional imaging. Cerebral perfusion study was achieved during the first pass of a bolus of gadolinium-based contrast agent. All post-processing MRI images were interpreted by two board-certified neuroradiologists (more than 10-year-experience), one radiology resident and one well-trained technician, who separately performed and blinded from the pathological results. RESULTS: Forty-four patients diagnosed as glioma were included in this study. There were 26 cases of high-grade and 18 cases of low-grade gliomas. The cerebral blood volume and flow and its ratios had a strong association with the grade of glioma. The areas under the ROC curve for CB K CBVratio (rCBV), CBF and CBF ratio (rCBF) are 0.778, 0.769, 0.769, and 0.772, respectively. On the basis of equal misclassification rates, a cutoff value of 6.15 for CBV (sensitivity, 81.5%; specificity, 64.7%), a cutoff value of 2.38 for the rCBV (sensitivity, 88.9%; specificity, 64.7%), a cutoff value of 0.66 for CBF (sensitivity 81.5%; specificity 70.6%), and a cutoff value of 2.6 for the rCBF (sensitivity, 85.2%; specificity, 70.60%) best discriminated the high and low-grade gliomas. CONCLUSION: Preoperative radiologic grading of gliomas based on conventional MR imaging is sometimes unreliable. The cerebral perfusion measurements can significantly improve the sensitivity and predictive values of radiologic glioma grading. The rCBV measurement is the best parameter for tumor grading due to the highest sensitivity.

Vertebral body compression fracture: discriminating benign from malignant causes by diffusion-weighted MR imaging and apparent diffusion coefficient value.

OBJECTIVE: To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) value in discriminating benign from malignant vertebral compression fracture. MATERIAL AND METHOD: 22 symptomatic patients with compression fracture of vertebra referred for conventional MRI spines during January 2009-March 2010 underwent additional diffusion weighted MR techniques. Evaluation of diffusion weighted MR imaging and quantified ADC value from reconstructed ADC map were performed. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of apparent diffusion coefficient (ADC) value were calculated. RESULTS: A total of 39 vertebral fractures; 7 malignant compression fractures and 32 benign compression fractures were evaluated. The difference between ADC values of malignant, benign compression fracture and normal vertebrae were statistically significant (p < 0.0001). The accuracy, sensitivity and specificity were 89.7%, 85.7% and 90.6% respectively with the ADC threshold of 0.89 to discriminate malignancy. CONCLUSION: The ADC promises to be an effective implement for characterization of vertebral body compression fracture in differentiating benign and malignant compression fractures.

Predictive value of magnetic resonance imaging in cervical spondylotic myelopathy in prognostic surgical outcome.

OBJECTIVE: Establish the predictive value of magnetic resonance imaging (MRI) for cervical spondylotic myelopathy as being a good operative outcome. MATERIAL AND METHOD: A retrospective study of the 52 consecutive patients with cervical spondylotic myelopathy underwent both magnetic resonance imaging (MRI) cervical spines examination at Siriraj Hospital between January 2005 and June 2007. Surgery was divided into two groups: "Good" operative outcome (35 patients) and "No improvement group" (17 patients). Two neuroradiologists independently identified the MR images data that showed the maximum stenosis on sagittal and axial sections and recorded predictive MRL parameters: T2-weighted signal change of the spinal cord, cross-sectional area of the spinal cord, anteroposterior (AP) diameter of the spinal canal and the spinal cord and AP-compression ratio (AP diameter/transverse diameter of the spinal cord). RESULTS: There were no statistically significant differences between both groups in all parameters. CONCLUSION: The AP-diameter of the spinal canal and spinal cord, AP-compression ratio and signal change of the spinal cord are not useful in predicting prognosis outcome in patients with cervical spondylotic myelopathy. In addition, cross-sectional area of the spinal cord cannot confidentially be used as predictive factor in CSM patients due to many influent factors of surgical outcome. A further prospective study without patient selective bias may offer more definite results to confirm these findings.

Optic-spinal inflammatory demyelinating disease: (OS-IDD) patients in Siriraj Hospital.

OBJECTIVE: To study the demographic data of optico-spinal inflammatory demyelinating disease (OS-IDD) patients at Siriraj Hospital between January 1997 and October 2006. DESIGN: Retrospective study of OS-IDD patients. RESULTS: There were 84 OS-IDD patients. Cerebrospinal fluid analysis revealed higher white blood cell count and neutrophilia in neuromyelitis optica (NMO) patients than those of multiple sclerosis (MS) patients. NMO had an average length of 4.1 segments of the cervical and 6.5 segments of thoracic cord involvement. CONCLUSION: Among Thai OS-IDD patients, on the basis of clinical features, NMO was hardly differentiated from MS.