Endobronchial Metastasis: CT Findings and Its Usefulness in Bronchoscopic Correlation

PURPOSE: To evaluate the CT findings of bronchial abnormalities in patients with endobronchial metastasis from extrapulmonary tumors, and to correlate these with the bronchoscopic findings. MATERIALS AND METHODS: The authors retrospectively reviewed the CT and bronchoscopic findings of 17 patients (M:F=9:8; mean age, 56 years) with histologically proven endobronchial metastasis from extrapulmonary primary tumors. Carcinoma of the uterine cervix (n = 5) was the most common primary site for endo-bronchial metastasis. CT findings of bronchial abnormalities with associated peribronchial and lung parenchymal lesions were analyzed and compared with the bronchoscopic findings. RESULTS: Among the 17 patients, 20 sites of bronchial abnormalities were visualized bronchoscopically. CT findings of bronchial abnormalities were smooth narrowing (n = 11), occlusion (n = 3), intraluminal mass (n= 4), and normal (n = 2). Peribronchial lesions(lymph node enlargement or parenchymal mass) were found in 12 cases. Bronchoscopy revealed bronchial narrowing due to a mucosal nodule or intraluminal polypoid mass in 16 cases, and total obstruction of the bronchus in four. With regard to the identification of bronchial abnormalities, the findings of CT and of bronchoscopy agreed in 17 cases and disagreed in three. While bronchoscopy was advantageous for detecting early mucosal abnormality, CT effectively evaluated the extent of a lesion beyond the stenosis or bronchial obstruction. CT was also useful for predicting the causes of bronchial abnormalities. CONCLUSION: CT is relatively accurate in evaluating bronchial abnormalities, and in patients with endo-bronchial metastases may be used as a complementary procedure to bronchoscopy for evaluating the extent of the lesion.

Pulmonary and Endobronchial Mucormycosis in a Diabetic Patient: A Case Report

Pulmonary mucormycosis is an opportunistic infection manifested by a fatal angioinvasive fungal pneumonia in immunocompromised patients or those suffering from uncontrolled diabetes. The radiologic findings are nonspecific, but there have been several reports of cases of pulmonary mucormycosis in which characteristic endobronchial lesions were present, with a more indolent clinical course in diabetic patients. We describe a case of pulmonary mucormycosis in a diabetic patient in whom endobronchial involvement was apparent.

Areas of Decreased Parenchymal Attenuation Associated with Bronchiectasis: Correlation between Severity and Extent of Bronchiectasis on HRCT with Pulmonary Function Test

PURPOSE: To determine the correlation between areas of decreased parenchymal attenuation seen in cases of bronchiectasis, and the severity and extent of the condition, as revealed by HRCT and the plmonary function test (PFT). MATERIALS AND METHODS: The findings of forty-five patients with bronchiectasis who had undergone PFT and HRCT were retrospectively analysed. CT scores were calculated according to the severity and extent of the condition, and areas of low attenuation, and the correlation coefficients between these were determined. Bronchiectasis was classified as either cylindrical or cystic, and using Student's t test, the statistical significance of the results of the PFT were determined. RESULT: The severity and extent of bronchiectasis correlated with the extent of areas of low attenuation (r > .45, p .44, p < .01). The functional parameters of the PFT which help differentiate between cylindrical and cystic bronchiectasis are FEV1, FVC, MMEF, DLCO (p < .01), RV, and TLC (p < .05). CONCLUSION: In patients with bronchiectasis, the extent of the condition correlated closely with the extent of low attenuation, and the latter, especially in cases of cylindrical bronchiectasis, showed significant correlation with the extent of abnormalities revealed by the pulmonary function test.

Airway Reactivity to Bronchoconstrictor and Bronchodilator: Assessment Using Thin-Section and Volumetric Three-Dimensional CT

OBJECTIVE: To determine the extent to which thin-section and volumetric three-dimensional CT can depict airway reactivity to bronchostimulator, and to assess the effect of different airway sizes on the degree of reactivity. MATERIALS AND METHODS: In eight dogs, thin-section CT scans were obtained before and after the administration of methacholine and ventolin. Cross-sectional areas of bronchi at multiple levels, as shown by axial CT, proximal airway volume as revealed by three-dimensional imaging, and peak airway pressure were mea-sured. The significance of airway change induced by methacholine and ventolin, expressed by percentage changes in cross-sectional area, proximal airway volume, and peak airway pressure was statistically evaluated, as was correlation between the degree of airway reactivity and the area of airways. RESULTS: Cross-sectional areas of the bronchi decreased significantly after the administration of methacholine, and scans obtained after a delay of 5 minutes showed that normalization was insufficient. Ventolin induced a significant increase in cross-sectional areas and an increase in proximal airway volume, while the effect of methacholine on the latter was the opposite. Peak airway pres-sure increased after the administration of methacholine, and after a 5-minute delay its level was near that of the control state. Ventolin, however, induced no significant decrease. The degree of airway reactivity did not correlate with airway size. CONCLUSION: Thin-section and volumetric spiral CT with three-dimensional reconstruction can demonstrate airway reactivity to bronchostimulator. The degree of reactivity did not correlate with airway size.

Evaluation of Tracheobronchial Diseases: Comparison of Different Imaging Techniques

OBJECTIVE: To compare the clinical utility of the different imaging techniques used for the evaluation of tracheobronchial diseases. MATERIALS AND METHODS: Forty-one patients with tracheobronchial diseases [tuberculosis (n = 18), bronchogenic carcinoma (n = 10), congenital abnormality (n = 3), post-operative stenosis (n = 2), and others (n = 8)] underwent chest radi-ography and spiral CT. Two sets of scan data were obtained: one from routine thick-section axial images and the other from thin-section axial images. Multiplanar reconstruction (MPR) and shaded surface display (SSD) images were obtained from thin-section data. Applying a 5-point scale, two observers compared chest radiography, routine CT, thin-section spiral CT, MPR and SSD imaging with regard to the detection, localization, extent, and characterization of a lesion, information on its relationship with adjacent structures, and overall information. RESULTS: SSD images were the most informative with regard to the detection (3.95 +/-0.31), localization (3.95 +/-0.22) and extent of a lesion (3.85 +/-0.42), and overall information (3.83 +/-0.44), while thin-section spiral CT scans provided most information regarding its relationship with adjacent structures (3.56 +/-0.50) and characterization of the lesion (3.51 +/-0.61). CONCLUSION: SSD images and thin-section spiral CT scans can provide valuable information for the evaluation of tracheobronchial disease.

Virtual Bronchoscopy: An Experimental Study on Parameters Affecting Apparent Sizes of Simulated EndobronchialLesions

PURPOSE: To evaluate the scanning parameters affecting the apparent sizes of endoluminal lesions of thetracheobronchial tree, as seen on virtual bronchoscopy(VB), and to determine the optimal CT parameters fordemonstrating the real sizes of endobronchial lesions. MATERIALS AND METHODS: Spherical beads of 8 mm - 10 mmdiameter were randomly placed in the airways of fixed pig lung. CT scans were obtained with collimation and pitchof 3 mm/1, 3 mm/1.5, and 5mm/1, respec-tively. Volumetric data were reconstructed with 1mm-, 1.5 mm-, and2mm-collimation for each parameter. VBs were reconstructed with shaded-surface technique and soft tissuealgorithm. A 10mm-sized bead in the trachea and two 8 mm-sized beads in the left main bronchus were selected andtheir longest diameters were measured on VB at varying thresholds from -800 to -2 00HU. RESULTS: When themeasured diameters of beads on VB were recorded as the percentage of real sizes, they were 1) 78.9 %, 77.5%, and73.7% at collimations and pitches of 3 mm/1, 3mm/1.5, and 5 mm/1, respectively; 2) 77.9 %, 76.9 %, and 75.1 % at 1mm, 1.5 mm and 2 mm reconstructions, respectively; 3) 86.2 % / 83.4% / 80.4% / 77.0% / 74.8% / 70.2% / 64.5% atisosurface thresholds of -8 0 0 /-7 0 0 /-6 0 0 /-5 0 0 /-4 0 0 /-3 0 0 /-200HU, re-spectively; 4) 85.6 %, 75.0 %,69.3% at 23 mm, 17 mm and 11mm luminal diameters of lesion location, respectively. CONCLUSION: Overall, thediameters of endobronchial lesions are underestimated on VB. As the isosurface threshold values, collimations,pitches and reconstruction interuals decrease in size, the measured diameters approach to real diameter of thebeads. Beads in peripheral airways appear smaller than those in proximal airways.

Helical CT of a Tracheobronchial Phantom: Angle and Optimal Window Affecting Size Measurements of ThreeDimensional Images

PURPOSE: To determine the effect of angle variation, relative to scan plan and optimal window setting, on thesize of three dimensional spiral CT images of a tracheobronchial tree using a phantom. MATERIALS AND METHODS:Spiral CT[collimation(mm)/table speed(mm/sec): 3/3; reconstruction interval:1.5 mm] was performed on atracheobronchial phantom consisting of a box filled with saline solution containing air-filled 5cc syringesoriented at varying angles relative to the scan plan. The diameter of three dimensional images was measured ateach window(minimal threshold value; -1000 HU; maximaml threshold value: from -300 HU to -500 HU; 50 HU interval). RESULTS: The inner diamenter of syringes used for tracheobronchial phantom was 12.55 +/-3.19mm. At all windows,as the angle became more perpendicular, the diameter of three-dimensional images increased, and at all angles, asmaxinal HU increased, measured diameter also increased(p<0.0001). In particular, at a maximal value of -500HU,measured values were closest to control values at all angles. CONCLUSION: Diameter can be measured close tocontrol value from three dimensional spiral CT images at maximal HU of -500 window, regardless of angle.

Intrathoracic Major Vessels, Trachea and Main Bronchi: The Effect of Respiration on Size

PURPOSE: To evaluate the effect of respiration on the sizes of intrathoracic vasculature, and the trachea,and the main bronchus. MATERIALS AND METHODS: Seventeen volunteers (10males aged 20-39 years and 7 females aged20-39 years) underwent spiral CT, between the apex and lowest base of the lung, collimation was 10mm, pitch was 1,and images were obtained at breath hold forced end-inspiration and breath hold forced end-expiration. Crosssecional areas or diameters were measured in each respiration state at the aorta (ascending, descending, lowerthoracic) and great branches, the IVC (thoracic, abdominal), the SVC, pulmonary artery (right main, leftdescending) and the tracheobronchus (trachea, left upper bronchus). Changes in the size of vessels and airwaysbetween the respiration states were evaluated and compared between inspiration and expiration. RESULT: Duringbreath-hold forced end-inspiration CT, the ascending, descending, and lower thoracic aorta and itsbranches(brachiocephalic, left common carotid, left subclavian) as well as the thoracic IVC and SVC and the rightmain and left descending pulmonary arteries decreased in size: during breath-hold forced end-expiration CT, thesize of all these vessels increased. For the trachea, left upper lobe bronchus and abdominal IVC, the situationwas reversed. Statistically significant changes(p<0.05) were noted in the ascending aorta and descending aorta,the lower thoracic aorta, the thoracic and abdominal IVC, the SVC, the right main and left pulmonary arteries, andthe trachea. CONCLUSION: During respiration, changes in the size of the thoracic vasculature and airways isprobably due to changes in intrathoracic pressure. In the measurement and diagnosis of stenosis or dilatation inthe intrathoracic vesculature and airways, respiration states should therefore be considered.

Bronchiectasis with Decreased Attenuation Areas on HRCT: Correlation with Pulmonary Function Test

PURPOSE: To evaluate the relationship between type, extent, and associated decreased attenuation areas ofbronchiectasis, as seen on high-resolution CT (HRCT), and abnormalities on pulmonary function tests. MATERIALS AND METHODS: We retrospectively evaluated 34 patients with bronchiectasis, in whom inspiratory and expiratory HRCTscans and pulmonary function tests were performed. HRCT scans were reviewed for the type (cylindrical vs. cystic)and extent of bronchiectasis (number of segments), and the extent of decreased attenuation areas seen oninspiratory (number of segments and CT scores) and expiratory scans (CT scores). With regard to the type andextent of bronchiectasis and the extent of decreased attenuation areas, as seen on HRCT, three radiologistsreached a consensus. We evaluated the relationship between pulmonary function tests (FEV1, FVC, FEV1/FVC, MMEF)and HRCT findings using Pearson correlation coefficients and linear regression (PC-SAS). RESULTS: In all patientswith bronchiectasis there were areas of decreased attenuation, as seen on inspiratory and expiratory HRCT. Theextent of bronchiectasis showed strong positive correlation with the extent of decreased attenuation seen oninspiratory and expiratory HRCT (p < 0.001). On pulmonary function tests, the extent of bronchiectasis anddecreased attenuation correlated negatively with FEV1, FVC, FEV1/FVC and MMEF. Cystic bronchiectasis tended to bemore extensive than the cylindrical variety (12.2 vs 7.6 ; CT score:34.7 vs 15.6) and expiratory scans (CT score :38.1 vs 19.1) CONCLUSION: There is significant correlation between the extent of morphologic abnormality, as seenon HRCT, and the physiologic impairment of pulmonary function tests in patients with bronchiectasis and associateddecreased attenuation areas.

Change of Pulmonary Arterial and Bronchial Diameter During Respiration: HRCT Findings

PURPOSE: To evaluate the changes and normal ranges of the artery-bronchus ratio (ABR) during respiration MATERIALS AND METHODS: We analyzed HRCT of 10 healthy adults. The HRCT findings of ten healthy adults were analysed. CT scanning was performed with 1 mm collimation at 3 mm intervals during full inspiration and full expiration, with a range during inspiration from 2 cm to 4 cm above the carina and from 4 cm above to 2 cm below the right hemidiaphragm. The range during expiration was from 1 cm to 3 cm above the carina and from 4 cm above to 2 cm below the right hemidiaphragm. ABiR (defined as the diameter of pulmonary artery divided by the inner diameter of the bronchus), ABoR (defined as the diameter of pulmonary artery divided by the outer diameter of the bronchus) and BLR (defined as the inner diameter of the bronchus divided by the outer diameter of the bronchus) were measured on the display console. RESULTS: The mean inner diameter of the bronchi was 2.04+/-0.73 mm during inspiration and 1.68+/-0.51 mm during expiration, while the mean diameter of the arteries was 3.95+/-1.03 mm during inspiration and 4.37+/-1.09 mm during expiration. The diameters of the bronchi were thus seen to increase during inspiration, and the diameters of the pulmonary arteries, to decrease. The mean thickness of the bronchial wall was 1.07+/-0.19 mm during inspiration and 1.06+/-0.24mm during expiration; thus, no change in thickness was seen during respiration (p<0.05). Mean ABiR was 2.01+/-0.60 (range 1.15-4.58) during inspiration and 2.59+/-0.74(range 1.16-4.9) during expiration, and in all cases the inner diameter of the bronchus was less than that of the accompanying pulmonary artery. Mean ABoR was 0.91+/-0.19 during inspiration and 1.09+/-0.22 during expiration. while for BLR, the corresponding fingures were 0.46+/-0.06, and 0.44+/-0.09. CONCLUSION: HRCT is a useful tool for evaluating changes in the pulmonary arteries and bronchi during respiration.

Three Dimensional Spiral CT of the Tracheobronchial Tree: Determination of the Optimal Window Settings

PURPOSE: To determine optimal window settings for measuring the inner diameter of the trachea and both mainbronchi by spiral CT. MATERIALS AND METHODS: Chest PA radiography and spiral CT scanning were performed in ten healthy adult volunteers. Three dimensional images were reconstructed (minimal threshold value : -1000HU ; maximal threshold value : from -200 to -900HU, of 50HU intervals) to measure the inner diameter of the trachea and both main bronchi. The results of 3D spiral CT were compared with those of chest radiography. RESULTS: The inner diameters of the trachea, right main bronchus, left main bronchus-I (1cm below the tracheal carina) and left mainbronchus-II (2cm below the tracheal carina) measured by chest radiograph and 3D spiral CT were not significantly different at maximal threshold values of -400 ~ -550HU, -450 ~ -550HU, -450 ~ -600HU and -500 ~ -600HU, respectively (p>0.05). The differences in the results of the two series were statistically significant at other threshold values however (p<0.05). CONCLUSION: We determined optimal window settings for measuring the inner diameter of the trachea and both main bronchi by spiral CT. The optimal maximal threshold values were somewhat different according to measured sites of the trachea and both main bronchi.

High-Resolution CT Appearance of Pulmonary Parenchymal Abnormalities Associated with Bronchiectasis: Correlation with Pulmonary Function Tests

PURPOSE: The purpose of this study was to evaluate the high-resolution CT(HRCT) appearance of abnormalities of small airways and lung parenchyma associated with bronchiectasis and to correlate HRCT appearance and the results of pulmonary function tests. MATERIALS AND METHODS: The author retrospectively reviewed medical recordsand HRCT scans of 33 patients with bronchiectasis. Abnormalities of small airways and lung parenchyma in lobeswith bronchiectasis were assessed on HRCT scan. The findings on HRCT were correlated with the results of pulmonary function tests in 20 patients. In two specimens obtained at lobectomy, histologic examinations were conducted to determine the pathologic basis for CT findings of disease of small airways. RESULTS: Patchy areas of low attenuation(n=27), centrilobular nodules or branching opacities(n=20), irregular hyper attenuation(n=16), and areasof ground-glass attenuation(n=4) were observed on HRCT scans. In the lobar evaluation, areas of low attenuation were observed in 66(76%) of the 87 lobes with bronchiectasis. Areas of low attenuation were also identified inseven(9%) of the 75 lobes without bronchiectasis. On expiratory HRCT, the lung parenchyma with areas of low attenuation did not show a normal increase in CT attenuation and remained more lucent than surrounding normallung, which suggested that air was trapped in the lung parenchyma. Of the 20 patients who underwent pulmonary function tests, six showed an obstructive pattern. These six had more lobes with bronchiectasis and with areas oflow attenuation than the other 14 patients, who did not have an obstructive pulmonary function pattern(p<.01). Intwo patients who had undergone lobectomy, pathologic examination showed bronchiolities obliterans in small airway speripheral to the dilated bronchi. CONCLUSION: In bronchiectasis, areas of low attenuation and centrilobular nodules or branching opacities are commonly observed in the lung parenchyma peripheral to the dilated bronchi on HRCT. These HRCT findings correspond pathologically to bronchiolitis obliterans and to lung parenchyma with trapped air. The number of loves with bronchiectasis and with areas of low attenuation correlate significantly with an obstructive pattern on pulmonary function tests.

Respiratory Dynamic CT: Functional Evaluation of Main Bronchial Stenosis

PURPOSE: To separately evaluate the respiratory function of both lungs separately in patients with unilateralmain bronchial stenosis or obstruction, applying respiratory dynamic CT using the spiral technique. MATERIALS AND METHODS: This study involved five normal subjects and six patients with main bronchial stenosis. Time-continuous scan data at a selected levels during forced vital capacity maneuver were obtained, and static images were retrospectively reconstructed using 0.67 sec. partial scan data per image. Time-density curves for controls and patients were plotted and compared. RESULTS: The highest values of mean attenuation were -697+/-9 H for the leftlung and -684+/-9 H for the right lung of controls, and -697+/-5HU for the healthy lung and -791+/-3H for thediseased lung of the patients. The lowest values were -837+/-2H for the left lung and -842+/-5H for the right lungof contorls, and -847+/-0H for the healthy lung and -858+/-4H for the diseased lung of patients. Mean durations ofexpiration were 1.64+/-.65 seconds for the left lung and 1.58+/-.50 seconds for the right lung of controls, and1.66+/-.60 seconds for the healthy lung and 1.96±.49 seconds for the diseased lung of patients. Time-attenuationcurves for the right and left lung of controls were not significautly different, but except for the lowest value of mean attenuation, these were signficantly different for the healthy and diseased longs of patients. CONCLUSION: Respiratory dynamic CT is an updated technique which permits imaging of the functional status of lung parenchy maduring respiration. It may be useful in the evaluation and quantification of lung function in patients with proximal airway stenosis.