Radiographic Features for Predicting Smear-Negative Pulmonary Tuberculosis.

Background: Diagnosis of smear-negative pulmonary tuberculosis (TB) in some circumstances remains a challenge to physicians especially those working in limited-resource settings. Objective: To investigate and examine radiographic characters as a predictor of true diagnosis of pulmonary tuberculosis in patients with negative sputum smears. Material and Method: This retrospective cross-sectional study was conducted in patients with smear-negative pulmonary TB at Siriraj Hospital between January 2013 and June 2014. Patients with previous TB treatment, HIV co-infection, significant pleural effusion, and corticosteroid therapy equivalent to prednisolone greater than 15 mg/day were excluded. Demographic and clinical data were collected and radiographic features were reviewed and classified as active or inactive TB by a consensus of three independent reviewers. Various diagnostic parameters for true prediction of TB, as defined by culture confirmation and/or radiographic improvement, were then examined. Results: There were 122 patients during the study period, 65 (53%) were male, 27 (22%) were asymptomatic, 20 (16%) had extrapulmonary involvement, and eight (7%) had concomitant diabetes mellitus. TB was confirmed in 92 patients (75%), 72 had positive culture and 20 had radiographic improvement. Miliary nodules and cavitary lesions had high specificity (100% and 100%, respectively) and low sensitivity (9.8% and 13%, respectively) for prediction of true TB. Focal interstitial and alveolar opacities had high positive predictive value (79.5 and 85%) and modest accuracy (62.3 and 47.5%). Conclusion: Given that specific radiographic features are uncommon and non-specific features are common in smear-negative pulmonary tuberculosis, clinicians should supplement clinical symptoms, radiological features, and radiological responses with mycobacterium TB culture to verify diagnosis of TB.

Relationship between emphysema quantification and COPD severity.

OBJECTIVE: To determine the association between emphysema extent from high-resolution computed tomography (HRCT) and the physiological derangement in patients with chronic obstructive pulmonary disease (COPD). MATERIAL AND METHOD: A cross-sectional study was undertaken to quantify the emphysema severity in 23 COPD patients by automated HRCT scoring techniques. Correlation with phenotypic characters in term of exercise capacity [Modified Medical Research Council (mMRC) dyspnea scale, and 6-minute walk distance (6MWD)], pulmonary function testing [spirometry (forced expiratory volume in 1 second, FEV1 and forced vital capacity, FVC), and diffusing capacity (DLCO)], were then assessed. RESULTS: Nineteen patients were male and four were female, the mean age was 73 ± 8 years, with the mean FEV1 % predicted of 67.8 ± 25.4. Percentage of inspiratory emphysematous lung volume (%ELVi) had significant negative correlation with %FEV/FVC (r = -0.50, p = 0.016) and DLCO (r = 0.58, p = 0.011). Percentage of expiratory emphysematous lung volumes (%ELVe) also had the same correlation with %FEV/FVC (r = -0.58, p = 0.004) and DLCO (r = 0.48, p = 0.042). In addition, %ELVe also had significant negative correlation with 6MWD (r = 0.50, p = 0.016), but had significant positive correlation with mMRC scale (r = 0.53, p = 0.01). CONCLUSION: Severity of emphysema assessed by HRCT was well correlated with pulmonary function test results and exercise capacity. It can be used as one aspect ofphenotypic characters in patients with COPD,for designing personalize management plan.

Cost effectiveness of combined CT pulmonary angiography (CTPA) and indirect CTV in patient with intermediate to high probability for pulmonary embolism.

OBJECTIVE: Evaluate the cost effectiveness of combined CTPA and indirect CTV for evaluation of patients with intermediate to high probability for pulmonary embolism using Wells criteria. MATERIAL AND METHOD: One hundred cases with moderate to high probability for pulmonary embolism according to Wells criteria were prospectively collected between December 2007 and January 2010. Combined CTPA and indirect CTV were performed. Positive findings were including the visualization of filling defect within the pulmonary artery and/or deep venous system of the lower extremities. Negative findings were including no demonstrable of filling defect within pulmonary artery and deep venous system of lower extremity plus absence of clinical manifestation of pulmonary embolism and deep vein thrombosis during 3-month follow-up. RESULTS: One hundred cases including 31 men and 69 women with age range 16 to 95 years (mean = 61.8) were collected. Four cases were excluded according to non-opacified of the lower extremities veins. The authors found that 36 cases (38%) had pulmonary embolism, while 60 cases (62%) were negative for pulmonary embolism. For the group with positive pulmonary embolism, 11 cases (31%) did not have DVT while 25 (69%) case also had DVT as well. In the negative pulmonary embolism group, 49 (82%) did not have DVT but 11 (18%) were shown to have DVT. CONCLUSION: For 96 cases with intermediate to high probability of PE, the authors needed to spend 70,909 baht more per case for the extra-investigation (combined CTPA and indirect CTV) for early detection of DVT. By comparison of two workup strategies, combined CTPA and indirect CTV of the lower extremities and CTPA with direct CTV of the lower extremities, the expense for detecting DVT in patients who also have PE will be 31,200 baht per case. Clinicians can use this value to judge between the cost effectiveness of this investigation and the expense of longer hospitalization and medical expense for late complication of DVT which was frequently found in patients with PE. In additional, indirect CTV can increase diagnosis of deep vein thrombosis in non-PE case up to 30% in the present study.

Diagnostic accuracy of multidetector computed tomography (MDCT) in evaluation for mediastinal invasion of esophageal cancer.

OBJECTIVE: Determine diagnostic accuracy of evaluation for mediastinal invasion of esophageal cancer by multidetector computed tomography (MDCT) as compared with post-operative histopathology staging. MATERIAL AND METHOD: The present study retrospectively analyzed the 64-slice MDCT of twenty-one patient's diagnosis with esophageal cancer who received surgical treatment in Siriraj Hospital. Patients were enrolled between June 1, 2004 and Dec 31, 2009. Twenty-one CT images of chest were evaluated by two radiologists without knowing each patient's history as determined by surgical and pathology findings. Image analysis was determined for evaluating tumor location, wall appearance, findings of direct mediastinal extension. Accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were evaluated for tumor staging and nodal staging. RESULTS: Concordance between the two different readers for the interpretations with a kappa coefficient to assess interobserver variation of0.2 to 0.9 suggests only slight agreement between the two readers. The overall sensitivity, specificity, PPV NPV and accuracy of CT T3 staging were 75%, 78%, 66.7%, 84.6%, and 77.3% respectively. The CT T4 staging had sensitivity 75%, specificity 85.7%, PPV 75%, NPV85.7%, and accuracy 81.8%. In N staging, NO staging from CT study had sensitivity 50%, specificity 33%, and accuracy 38%. NI staging from CT study had sensitivity 33%, specificity 50%, and accuracy 38%. CONCLUSION: 64-slice MDCT can be evaluated for mediastinal tumor invasion of esophageal cancer with high sensitivity, specificity, and accuracy. The metastatic node and reactive lymphadenopathy in esophageal cancer were equivocal to discriminating from CT findings, especially using 1 cm in diameter of short axis as cut point.

Distinguishing small primary lung cancer from pulmonary tuberculoma using 64-slices multidetector CT.

OBJECTIVE: To evaluate which CT findings help in distinguishing small primary lung cancer from tuberculoma. MATERIAL AND METHOD: Forty-two chest CT studies with pathological diagnosis of primary lung cancer (n = 27) and tuberculoma (n = 15) were retrospectively reviewed by two radiologists who were blind to the pathological results. The CT findings of number; size, shape, border and location of the nodules, the presence or absence of satellite nodule, contrast enhancement, internal air bronchogram, internal calcification, internal cavitation, bronchovascular invasion, and bony destruction were evaluated. RESULTS: About 96% of primary lung cancer had a solitary lesion compared to only 60% among tuberculoma (p < 0.05). The nodule size > 2-3 cm is more likely to be primary lung cancer compared with tuberculoma (p = 0.058). Both primary lung cancer and tuberculoma can occur in all lobes of both lungs but more frequently in the upper lobe, which has no statistically significant difference between these two groups. Tuberculoma seems to be round or polygonal shape and primary lung cancer is more likely to be lobulated shape. The smooth border nodule is found only in tuberculoma (27%) whereas 93% of primary lung cancer had spiculated border compared to 73% among tuberculoma (p < 0.05). Tuberculoma seems to have more satellite nodule than primary lung cancer (47% vs. 22%, p = 0.163). The enhancement of nodule and air bronchogram are significantly found in primary lung cancer compared with tuberculoma (p < 0.05). Tuberculoma seems to have dense central calcification and primary lung cancer seems to have punctate calcification (p < 0.05). Most of the primary lung cancer and tuberculoma do not have internal cavity. The presence of bronchovascular invasion was significantly found in primary lung cancer compared with tuberculoma (p < 0.05). No evidence of bony destruction was observed in both pulmonary tuberculoma and primary lung cancer groups. CONCLUSION: The solitary lesion size < 3 cm in diameter with spiculated border contrast enhancement, presence of air bronchogram, punctate calcification and bronchovascular invasion are useful CT findings for diagnosis of primary lung cancer However, the lesions with inconclusive findings, tissue diagnosis may be necessary.

Comparison of low dose and standard dose MDCT in detection of metastatic pulmonary nodules.

OBJECTIVE: Compare low dose (50 mA) and standard dose (300 mA) MDCT in detection of metastatic pulmonary nodules in extrathoracic malignant patients in Siriraj hospital. MATERIAL AND METHOD: Prospectively, 58 patients underwent chest CT examinations by 64-slice MDCT in non-enhanced phase with a reduced tube current of 50 mA (low-dose CT (LDCT)), followed by contrast-enhanced phase with a standard tube current of 300 mA (Standard-dose CT (SDCT)). Otherparameter such as tube voltage 120 kVp, spiral pitch 0.984, and section thickness 1.25 mm, were kept constant. Four hundred twenty two nodules found by SDCT and 427 nodules found by LDCT were analyzed. RESULTS: The sensitivity of LDCT was 94.7% for all nodules, 79% for nodules < or =2 mm, 94.2% for nodules 2.1-3 mm, 97% for nodules 3.1-4 mm, and 100% for nodules 4.1-5 mm. Three types of nodules were found and classified as calcific nodule, non-calcific nodule, and ground-glass nodule of which sensitivity for detection in LDCT were 100% (p = 1.000), 95.9% (p = 0.337) and 77% (p = 0.581), respectively. Most common causes of discrepancy in SDCT were unseen nodules and in LDCT were end-on vessel nodules. Majority of discrepant nodules and retrospective nodules were < or =3 mm. Effective dose ranged from 0.78 mSv.-1.6 mSv in LDCT and 4.22-9.57 mSv in SDCT. CONCLUSION: There is no statistical difference in detection of metastatic pulmonary nodules by using low-dose and standard-dose CT images. Low-dose CT images can used to follow-up the treatment responsiveness of the known patient, diagnosed to have pulmonary metastasis.

Characteristics, complications, and mortality of respiratory syncytial virus compared with influenza infections in hospitalized adult patients in Thailand.

INTRODUCTION: RSV is increasingly recognized in adults. An improved understanding of clinical manifestations and complications may facilitate diagnosis and management. METHODS: This was a retrospective study of hospitalized patients aged ≥ 18 years with RSV or influenza infection at Siriraj hospital, Thailand between January 2014 and December 2017. RESULTS: RSV and/or influenza were detected by RT-PCR in 570 (20.1%) of 2836 patients. After excluding patients coinfected with influenza A and B (n = 5), and with influenza and RSV (n = 3), 141 (5.0%) RSV and 421 (14.8%) influenza patients were analyzed. Over the study period, RSV circulated during the rainy season and peaked in September or October. Patients with RSV were older than patients with influenza and presented significantly less myalgia and fever, but more wheezing. Pneumonia was the most common complication, occurring in 110 (78.0%) of RSV cases and in 295 (70.1%) of influenza cases (p = 0.069). Cardiovascular complications were found in 30 (21.3%) RSV and 96 (22.8%) influenza (p = 0.707), and were reasons for admission in 15 (10.6%) RSV and 50 (11.9%) influenza. The in-hospital mortality rates for RSV (17; 12.1%) and influenza (60; 14.3%) were similar (p = 0.512). CONCLUSIONS: In Thailand, RSV is a less common cause of adult hospitalization than influenza, but pulmonary and cardiovascular complications, and mortality are similar. Clinical manifestations cannot reliably distinguish between RSV and influenza infection; laboratory-confirmed diagnosis is needed.

Helpful CT findings for giving specific diagnosis of anterior mediastinal tumors.

OBJECTIVE: To characterize the CT features of common anterior mediastinal tumors and evaluate CT findings that may help in suggesting specific diagnosis among these tumors. MATERIAL AND METHOD: Fifty chest CT studies with pathological diagnosis of thymoma (n=28), mediastinal germ cell tumor (n=14) and lymphoma (n=8) were retrospectively reviewed by two radiologists who were blind to the pathological results. The CT findings of fat, cyst and calcification within the lesion, contrast enhancement, associated intrathoracic findings such as mediastinal invasion and lymph node enlargement were evaluated. RESULTS: Fat density within the mass was present in 57.1% with germ cell tumor which was significantly higher than other anterior mediastinal tumors (p < 0.05). The presence of associated mediastinal lymphadenopathy was significantly found in lymphoma (75.0%) compared to other tumors (p < 0.05). The other CT findings showed no significant difference among these diseases (p > 0.05). CONCLUSION: The CT findings that help in giving specific diagnosis of anterior mediastinal tumors which are fat attenuation and associated mediastinal lymphadenopathy. The presence off at attenuation is highly suggestive of germ cell tumor and anterior mediastinal mass associated with mediastinal lymphadenopathy elsewhere is indicative of lymphoma.