Predictive value of MRI and CT findings in childhood medulloblastoma studied in Thai patients.

Objective: To evaluate the prognostic value of CT and MRI findings in patients with medulloblastoma. Methods: From 1998 to 2007, the MRI and CT of fourteen patients with medulloblastoma were retrospectively reviewed. The findings of cyst or necrotic portion, composition of calcification, hemorrhage and residual tumor after surgical removal were evaluated. Histopathologic findings were classified as large cell and non-large cell type. Outcomes of the disease were indicated by evidence of leptomeningeal seeding, a recurrence event and survival time after diagnosis. Results: Only the large cell type of medulloblastoma was statistically significant in decreasing survival time. No other MRI or CT findings were statistically significant to predict outcomes of the disease. Conclusion: The histologic type of medulloblastoma is a predictive indicator of the outcome of treatment regardless of imaging findings. However, the limitation of this study due to small sample size was considered.

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.

Reliability study of white matter rating scale for the dementia and disability in Thai Elderly Project.

OBJECTIVE: To study the reliability of white matter rating scale on magnetic resonance imaging (MRI) of elderly patients in the urban community of Bangkok. MATERIAL AND METHOD: One hundred elderly with clinical diagnosis of cognitive impairment in the urban community around Siriraj Hospital underwent cranial MRI according to the Dementia and Disability in Thai Elderly Project. The axial T1wi, T2wi, and fluid attenuated inversion recovery (FLAIR) were separately assessed by two neuroradiologists. The assessment included white matter change by using Scheltens' rating scale, atrophy, and evidence of infarction. The inter-rater agreements were analyzed. RESULTS: The inter-rater agreement of periventricular hyperintensities, white matter, basal ganglion and infratentorial foci of hyperintensities were very good (ICC = 0.89-0.98). The agreement was good for central atrophy (Kw = 0.66) and moderate for cortical atrophy (Kw = 0.49). The silent infarction was found in the study population and divided into cortical (15%), subcortical (26%), brainstem (3%), and infratentorial infarction (8%). CONCLUSION: White matter hyperintensities was an important radiological criteria for diagnosis of vascular dementia. Appropriate rating scale is necessary especially in research study. The authors found that Scheltens rating scale needed some training and slightly time consuming at the beginning but was a good reliable tool.

Radiographic chest findings and clinical correlations in leptospirosis.

OBJECTIVE: To determine the clinical presentations, radiographic chest findings, and their correlation in patients with leptospirosis. DESIGN: A cross sectional study. SETTING: Between July 2001- December 2002 at 3 hospitals in North Eastern Thailand. MATERIAL AND METHOD: Two hundred and forty patients with laboratory confirmed leptospirosis. RESULTS: Two hundred and nine (87.1%) patients were males. The mean age was 37.53 years (range 13-76). The median duration of fever was 3 days (range 1-13). Overall, 154 patients (64.2%) had respiratory symptoms and 26 (10.8%) patients had hemoptysis. Jaundice was detected in 76 (31.7%) patients, hypotension in 50 (20.8%), renal dysfunction in 80 (30%), and multiorgan dysfunction in 62 (25.8%) on admission. One hundred and fifty-four (64.17%) patients had abnormal chest radiographs on admission (classified as cardiovascular, pulmonary, and mixed cardio-pulmonary involvement in 40 (25.97%), 41 (26.62%), and 73 (47.4%) patients, respectively). Jaundice was significantly associated with the likelihood of having abnormal chest radiography on admission. Air- space nodules detected on the chest radiograph were significantly more common in patients with renal dysfunction and patients who required mechanical ventilation. CONCLUSION: Pulmonary and cardiovascular involvements are common in leptospirosis. Air-space nodules detected by chest radiography may indicate severe leptospirosis.

Cranial dural arteriovenous fistula: Predisposing factors to aggressive symptoms.

Objective: To evaluate the clinical and angiographic data of cranial dural arteriovenous fistula in Thai patients and to determine the predisposing factors to aggressive symptoms. Methods: Retrospective review of 71 patients with cranial dural arteriovenous fistula who underwent cerebral angiography at Siriraj Hospital between July 2002 – February 2006. Their clinical manifestations were classified as benign or aggressive symptoms. The relationship between aggressive symptoms and the following factors were studied: gender, location of the fistula, classification according to venous drainage pattern, presence of cerebral sinus thrombosis, and shunt multiplicity. Linear-by-linear association and chi-square test were used to determine statistical significance. Results: Sixteen (22.5%) of 71 patients with cranial dural arteriovenous fistula had aggressive presenting symptoms. Factors that significantly correlate with aggressive symptoms were location of the fistula, retrograde leptomeningeal venous drainage, presence of cerebral sinus thrombosis, and multiplicity. Factor which was not significantly correlated with aggressive symptoms was gender. Conclusion: This study evaluated clinical data and angiographic features of cranial dural arteriovenous fistula in Thai patients. Predisposing factors to aggressive symptoms were location of the fistula, retrograde leptomeningeal venous drainage, presence of cerebral sinus thrombosis, and multiplicity.

MRI of multiple sclerosis in Thai patients.

OBJECTIVE: Evaluate the MRI findings of multiple sclerosis (MS) in Thai patients and compare these with the McDonald criteria for dissemination in space. MATERIAL AND METHOD: A retrospective study was performed by reviewing clinical and MRI records of patients attending MS clinic at Siriraj Hospital. Only patients with complete clinical and MRI data were included in the present study. RESULTS: There were 25 patients included in the study. Twenty-four patients were females and 1 was male. The mean age was 35.24 years old (range 16-50). The disease duration was 1 month to 17 years after the onset. Twenty-three patients were diagnosed as relapsing-remitting MS, one as possible MS and one as clinical isolated syndrome. Analysis for CSF oligoclonal bands was performed in 22 cases with positive results in 6 cases (27.3%). The sites of involvement were optic neuritis (16 cases), spinal cord (14 cases), and brain (9 cases). Seventeen cases had MRI study at the early presentations, and 8 cases during subsequent relapses. In the 9 cases with brain symptoms, all had positive brain MRI. Ten cases (58.8%) had infratentorial lesions mostly found at the medulla. Most T2 lesions were found at juxtacortical and periventricular regions. Five in 9 cases (55.6%) with periventricular lesions had lesions not less than 3 mm and at least 3 lesions were found. There were 6 cases (35.3%) with, at least, nine T2 lesions. Most of the T2 lesions were oval shaped. Seven cases (41.2%) had black hole lesions. Three cases (17.6%) had gadolinium enhanced lesions. Thirteen of 15 available spinal MRI were abnormal. The locations of the lesions were cervical (6), thoracic (4) and cervicothoracic (3) levels. The number of T2 lesions was one in 8 cases and more than one in 5 cases. The length of each lesion varied: less than 1 vertebral segment (5 cases) and 2 or more vertebral segments (8 cases). Swelling of the cord was found in 3 cases and atrophy in 7 cases. The lesions occupied the whole cross-sectional cord in 6 cases and center of the cord in 7 cases. The gadolinium enhancement was found in 6 cases with a patchy pattern in 5 cases and mixed ring and patchy patterns in 1 case. There were totally 6 cases (24%) that fulfilled the McDonald MRI criteria for dissemination in space. CONCLUSION: The MRI findings in Thai MS have distinct features from the Western reports. Re-evaluation of McDonald criteria for the Eastern countries is needed.

HRCT of pulmonary tuberculosis mimics malignancy: a preliminary report.

OBJECTIVE: To evaluate potential predictors of high resolution CT (HRCT) findings of pulmonary mass caused by tuberculosis (Tbc). MATERIAL AND METHOD: A retrospective study of chest HRCT was performed in 10 patients diagnosed as pulmonary Tbc. The size, characteristics of lesions, enhancement and mediastinal lymphadenopathy were interpreted. The final diagnosis was reached by laboratory and pathological specimens or clinical improvement from treatment of the Tbc. RESULTS: Of 10 patients, 6 were males and 4 were females. The mean age was 53.5 years old. There were 13 masses analyzed. The mean size of the lesions was 2.3 cm and 53.8% had diameters more than 2 cm. The locations of lesions were right upper lobe (30.8%), right middle lobe (7.7%), right lower lobe (38.5%) and left upper lobe (23.1%). Calcification was found in two lesions. The HRCT findings were spiculated margin (76.9%), lobulated margin (23.1%), smooth margin (7.7%), ground-glass opacity (23.1%), concave border (61.5%), polygonal shape (53.8%), air bronchogram (38.5%), pseudocavity (15.4%), pleural tag (30.8%), distortion of vessels (23.1%), satellite lesions (38.5%), and peripheral subpleural lesion (46.2%). Only 7 cases of enhanced study were available and two cases showed enhancement. Of the 10 cases, mediastinal lymphadenopathy was found in 8(80%) cases. The size of the lymph nodes was less than 2 cm in 6 cases and larger than 2 cm in 2 cases. Other associated findings were pleural thickening or effusion (60%), evidence of volume loss (20%), emphysema (40%), and infiltrations (50%). CONCLUSION: Many characteristics of Tbc lesion on HRCT mimic reported malignant lesions. Re-evaluation of value of HRCT for controversial lesions is needed

The limited protocol MRI in diagnosis of lumbar disc herniation.

OBJECTIVE: To assess agreement in detection of lumbar disc herniation (LDH) between limited and full protocol MRI. MATERIAL AND METHOD: 123 patients who requested lumbar MRI for diagnosis of disc herniation were assessed The full protocol MRI composed of sagittal T1-wi, sagittal T2-wi and axial T2-wi was performed on each patient. The sagittal T2-wi was selected as the limited protocol MRI. The limited and full protocols MRI of each patient were separately interpreted by three neuroradiologists to assess disc herniation and nerve root compression. The consensus results of limited and full protocol were compared. The diagnostic performance of each protocol was analyzed using surgery as the gold standard. RESULTS: There were 62 females and 61 males enrolled into the study between the age of 21-60 years old (means = 42.91 years). The duration of pain was 1-204 months (mean = 31.20 months). The degree of severity was mild in 23.58%, moderate 45.52% and severe 30.89% of cases. Thirty-three cases were operated on. For detection of LDH, the limited protocol gave the same interpretation results as the full protocol (0 = 1.04, 95%CI = 0.94, 1.14 with accepted range of 0.95-1.05). In nerve root compression, the limited protocol was not accurate as the full protocol (0 = 0.75, 95%CI = 0.87, 0.63). The sensitivity, specificity, accuracy, PPV, NPV, and LR+ in the surgical group of limited protocol in diagnosis of LDH were 82.61%, 80%, 81.82%, 90.48%, 60.67%, 4.13 and in nerve root compression were 54.84%, 100%, 57.58%, 100%, 12.5% respectively. The same statistics of full protocol MRI in diagnosis of LDH were 82.61%, 70.80%, 78.79%, 86.36%, 63.64%, 2.75 and of nerve root compression were 80.65%, 100%, 81.82%, 100%, 25% respectively. The sensitivity and specificity in diagnosis of LDH were not different in both protocols but the sensitivity of nerve root compression was statistically significant different (p < 0.013, 95%CI = -0.33, -0.25). CONCLUSION: The authors concluded that limited protocol MRI may replace full protocol MRI in diagnosis of LDH but not in nerve root compression.

CT criteria in vascular dementia: A study in Thai population.

Objective: To evaluate CT criteria for diagnosis of vascular dementia (VaD) in Thai population. Methods: Cranial CT was performed in the elderly from an urban community in the west of Bangkok. The evaluation of infarction (number, location and volume of infarction), white matter low attenuation, and atrophy were performed by neuroradiologists; and, the final diagnoses of dementia were done by neurologists. Results: Ninety-one patients were recruited into the study with their mean age of 70.16 years old (range = 53-90). Twenty-seven patients were males and 64 were females. The final diagnoses were, namely: normal cognition (10=11%), vascular dementia (30=33%), Alzheimer’s disease (AD) (41=45.1%), and mixed VaD and AD (10=11%). On CT, most patients had infarction of less than two lesions and the volume of infarction was less than 25 ml. Two (2.2%) patients who were diagnosed as AD and one who was diagnosed as normal had lesions more than one lesion; whereas 11 (12.1%) patients who were diagnosed as VaD had more than one lesion. No patients who were diagnosed with AD or those who were normal had infarction volume more than 25 ml, except two patients who were diagnosed with VaD had infarction volume more than 25 ml. Most patients who had white matter scale more than 2 were VaD (52%). No significant difference between atrophy and dementia was found. With the CT grading criteria of 0 for non-VaD and combined 1, 2 and 3 for VaD, the sensitivity, specificity and accuracy for diagnosis of VaD were 96%, 64.7%, and 76.5%, respectively. Conclusion: Modified CT criteria for VaD established by reducing volume of infarction regardless of the atrophy are helpful to identify VaD patients with improved diagnostic performance.

Spiral CT in the diagnosis of pulmonary embolism.

Objective: To evaluate the usefulness of spiral computed tomography (CT) in the diagnosis of pulmonary embolism (PE). Methods: A retrospective study was performed on 52 patients who underwent CT angiography (CTA) using spiral CT at our department from May 2000 to August 2003. A thoracic radiologist who was blinded to the database reviewed the radiological findings in all examinations from clinical data. A final diagnosis of PE was made by clinical conclusion from all other investigations, laboratory results and treatment outcome. Results: From 52 cases recruited into the study, 24 cases were suspected of PE before the examinations. Sixteen cases resulted in a final diagnosis of PE with acute PE in 7 cases and chronic PE in nine. The CTA correctly diagnosed PE in eleven cases, two cases were false-negative; CTA was proven to indentify PE that were detected through conventional angiography. Seventeen lesions of intraluminal filling defects were found, two of which were main pulmonary arteries (PA), four lobar and eleven segmental PA. The CT findings of clots consisted of six complete filling defects, two central clots and nine eccentric clots. The other findings, such as intraluminal web, calcification of clots, enlarged vessels and irregular thickening of vessel walls, were also demonstrated. Ancillary findings found in this study were atelectasis, oligemia, mosaic pattern and pleural effusion. Conclusion: Spiral CT is a useful method for the diagnosis of PE.

Vascular loop compressing facial nerve in hemifacial spasm: demonstrated by 3D-phase contrast magnetic resonance angiography in 101 patients.

BACKGROUND: Vascular compression of the facial nerve is deemed to be the common cause of hemifacial spasm producing emphatic transmission. Although facial nucleus supersensitivity is more accepted as the main cause of hemifacial spasm. PURPOSE: To determine the vascular loop compression of the facial nerve in patients with hemifacial spasm by 3D-phase contrast (PC) magnatic resonance imaging (MRI). MATERIAL AND METHOD: A retrospective study of 101 patients with hemifacial spasm who went MRI and magnetic resonance angiography (MRA) of the brain was done. The magnitude images of the 3D-PC MRA was evaluated in axial and oblique coronal reconstruction planes blindly from symptomatic information. RESULTS: Among 101 patients, 53 affected the left side, 48 patients were right sided and none had bilateral involvement. Vascular loop compressing on the symptomatic side was found in 61 (60.4%) patients. For the asymptomatic side, there were 14 (13.86%) with vascular loop contact. Five patients (4.9%) had bilateral vascular compression. The proportion of vascular contact of the symptomatic and asymptomatic side was significantly different (with p < 0.001). The offending vessels were vertebral artery (32, 52.46%), posterior inferior cerebellar artery (7, 6.93%), anterior inferior cerebellar artery (6, 5.94%) and artery of uncertain origin (16, 26.23%). CONCLUSION: The study implied the usefulness of this simple technique to demonstrate the neurovascular contact of the facial nerve.

Imaging findings and prevalence of central precocious puberty at Siriraj Hospital.

Central precocious puberty occurs as a result of premature pituitary stimulation and increased secretion of gonadotropins. The differential diagnosis of true precocious puberty includes cerebral and idiopathic categories. This differentiation, which cannot be made endocrinologically due to similarities in pituitary gonadotropin and sex steroid levels, may facilitatic by Magnetic Resonance Imaging (MRI) of the brain. Objective: To analyze MR imaging findings and incidence of each pathology in central precocious puberty, and to compare pituitary height in patients with central precocious puberty with patients in a control group. Materials and methods: A retrospective study of central precocious puberty in 22 patients was performed from March 2002 to July 2003. The control group consisted of 54 boys and 46 girls. Analyzed parameter included pituitary height, shape and posterior bright spot. The shape was assessed by a pituitary grading system which was based on the concavity of the upper pituitary surface (grade 1 = marked concavity, grade 2 = mild concavity, grade 3 = flat, grade 4 = mild convexity, grade 5 = marked convexity). Bone age, and pelvic ultrasonography were evaluated in the study group. Results: Twenty two children with central precocious puberty (4 boys and 18 girls) were divided into two subgroup according to MRI findings as follows : idiopathic 15 patients (68.18%) and noidiopathic 7 patients (3 patients had nodule at pituitary stalk, 2 had microadenoma, 1 had germ cell tumour at pinealgland, and 1 had hypothalamic harmatoma). The mean pituitary height in the study group was 5.59 mm (SD 1.7). The mean height of the control group was 5.25 mm. There was significant difference among the two groups (p < 0.005). Conclusion: The most common cause in central precocious puberty is idiopathic. However the MRI is necessary to necessary to excluding the surgical cause as tumor. Pituitary height of more than 5.25 mm may be a helpful variable for follow up the result of medical treatment in precocious children.

Multiplanar reconstruction computed tomography of lumbar spinal stenosis in correlation with surgical findings: Initial experience.

Lumbar spinal stenosis is a debilitating illness affecting middle-aged and elderly people. There are several imaging modalities available for use in affirming the diagnosis. The CT provides excellent osseous detail of osteophyte, fracture and location of bony abnormality and extension to adjacent soft tissue. New spiral CT technology allows multiplanar images to be obtained quickty and easily. Among these, multiplanar reconstruction computed tomography (MPR-CT) is the specific means to assess narrowed lumber spinal canal. This present work was done in order to evaluate the reliability of MPR-CT in diagnosing lumber spinal stenosis by correlation with operative finding. From July to December 2002, MPR-CT was done on 10 patients and evaluated by a well-known radiologist. Seven patients were approached surgically and the remaining three treated medically. Subsequently, the following variables were analyzed: central canal stenosis, lateral canal stenosis, fornminal stenosis, dise herniation, nerve root compression, ligamentum flavum hypertrophy and spondylolisthesis. The results of MPR-CT were in good correlation with finding from surgical exploration; the positive predictive values of central canal atenosis, lateral canal stenosis and foraminal stenosis were 77.7%, 75% and 50% respectively which were higher than those for disc herniation or nerve root compression. Typical claudication was found in 10% of the cases and the most common affected level was L4-L5. Therefore, MPR-CT which composed of axial, coronal and sagittal views was shown to be an application imaging modality because of its reliability.

Correlation between serum creatinine levels and underlying risk factors for renal disorders in a group of patient undergoing computed tomography using intravenous iodinated radiographic contrast medium.

Intravenous administration of iodinated radiographic contrast media has been known to have nephrotoxic side effects especially patients with renal disorders. Ideally, each patient should have serum creatinine measured before administering the contrast media. This is costly in termed of time and finance and is not practical in our situation here at Siriraj Hospital. The aim of this study is to determine whether serum creatinine levels correlate with the patient's underlying risk factors. The data were collected from 81 patients who were sent for computed tomographic examination. 63 patients (77.78%) were found to have underlying risk factors. These included hypertension 21 cases (33.33%), diabetes mellitus 18 cases (28.57%), administration of chemotoxic drugs 13 cases (20.64%), renal disease 4 cases (6.35%), high serum uric acid 4 cases (6.35%), AIDS 2 cases (3.17%), and ACEI 1 case (1.59%). Of these, only 5 cases (6.17%) were found to have abnormally high serum creatinine levels (over 2 mg/dl), all had underlying risk factors and were over 60 years old.

The accuracy of magnetic resonance venography for diagnosis of dural sinus thrombosis.

A retrospective study of 24 patients who underwent magnetic resonance venography (MRV) was performed. The MRV was using a 3D-PC technique and thick-slab multiplanar reconstruction. Four patients underwent conventional angiography. There were 4 males and 20 females with an age range of 8-71 years. The MRV was considered as positive for dural sinus thrombosis (DST) in 8 patients and negative in 16 patients. There were 2 false positive in the MRV.The sensitivity of MRV is 100%,specificity 88%,positive predictive value 75% and negative predictive value 100%.We concluded that MRV is a valuable screening method for DST. One pitfall concerning the use of MRV is that a false positive interpretation may occur due to hypoplasia of the transverse sinus which is a normal variant.

Value of computed tomography in T-stage assessment and therapy of nasopharyngeal carcinoma.

The accurate evaluation of tumor size, localization and spread of nasopharyngeal carcinoma help optimal treatment planning. The purpose of our retrospective study is to compare the T-stage of nasopharyngeal carcinoma between evaluated by physical examination and CT scan and to compare the response to treatment in the group also underwent CT (147 patients) and the group without CT staging (40 patients). The sex ratio, and the mean age of the patients in both groups was not significantly different. Radiological study showed Stage 1 the tumor confined in nasopharyngeal region. Stage II showed tumor spreading with lateral extension to the parapharyngeal region. Stage III and stage IV, the tumor spread in a superior direction to the paranasal sinus and the base of the skull. CT staging resulted in upgrading the T stage in 88/147 cases ( 59.9%). A Complete response was higher in the CT than the non CT Group at the T2 and T4 stage. CT imaging is better than clinical examination and conventional imaging in detecting the involvement of more than one wall, base of skull involvement, differentiating tumor from sinusitis, detecting intracranial invasion and neck node involvement. In Conclusion, a CT scan is require in nasopharyngeal carcinoma patients for accurate staging, modified radiation treatment and improved treatment results.

Radiopathological Conference: Differences in CT findings of mediastinal lymphadenopathy between metastasis and tuberculosis not always applicable.

A case report of male patient with a right neck mass is discussed .The initial diagnosis was tuberculosis. The plain film chest and CT chest also demonstrated mediastinal lymphadenopathy. The autopsy and pathology findings indicated adenocarcinoma of lung.

Radio-pathological conference, Siriraj Hospital wegener's granulomatosis.

A case report of male with history of headache, right eye swelling and blood-tinged nasal discharge was shown with typical findings of CT chest and MRI brain of the wegener's granulomatosis. The pathological finding was also shown and correlated.

Radiopathological conference of Siriraj Hospital pleomorphic Xanthoastrocytomas: A rare brain tumor.

A case report of female with long-standing history of seizure was shown with typical findings of CT and MRI brain of left temporal lobe pleomorphic xanthoastrocytomas. The pathological finding was also shown and correlated.

Nocardial brain abscesses.

Five cases of nocardial infection of central nervous system were reported. All patients were immunocompromised hosts due to corticosteroid and cytotoxic drugs therapy for underlying disease. Two cases showed disseminated infection. The imagings of brain abscess were presented.