European Journal of Radiology, 10 (1990) 130-133 Elsevier
130
EURRAD
00021
The positive bronchus sign in patients with known lung cancer G. Zacharopoulos
‘, A. Adam’
and P.W. Ind2
Departments of ‘DiagnosticRadiology and ‘Medicine. Royal PostgraduateMedical School, Hammersmith Hospital, London, U.K. (Received 29 September
Key words: Computed
1989; accepted
tomography,
13 October
chest; Bronchoscopy;
1989)
Lung cancer, CT
Abstract The positive bronchus sign is the CT finding of a bronchus leading to or contained within the primary mass. A prospective study was performed for the purpose of establishing the correlation between the above sign on CT and the visual and pathological tindings on bronchoscopy. The predictive value for the positive bronchus sign was found to be 94% and that of the negative bronchus sign 62%. CT is useful in predicting the likelihood of subsequent bronchoscopy providing positive results.
Introduction Lung cancer is a leading cause of death in men and women [2,5]. Computerized tomography (CT) and fiberoptic bronchoscopy (FOB) are extensively used in the assessment of patients with known or suspected lung cancer [ 51. Although recent studies report very good correlation between CT and both visual and pathological FOB findings [ 1,7] it is not known whether CT can increase the diagnostic yield of FOB with regard to the primary tumour. A ‘positive bronchus sign’, the CT finding of a bronchus leading to or contained within the nodule or mass, has been claimed to be very useful in the routine evaluation of pulmonary nodules prior to FOB, since the likelihood of obtaining a diagnostic cytological specimen from FOB is significantly increased if the sign is present [ lo]. The aim of this study was to establish the agreement between the ‘positive bronchus sign’ and the yield of FOB in patients with known lung cancer. Patients and Methods The records of 110 patients with documented lung cancer who had been investigated at Hammersmith Address for reprints: Dr. G. Zacharopoulos, Diagnostic Radiology, Hammersmith Hospital, London W12 OHS, U.K. 0720-048X/90/$03.50
Department of Du Cane Road,
0 1990 Elsevier Science Publishers
Hospital were evaluated retrospectively. Forty-four patients were excluded from the study, because plain chest radiography, FOB and/or percutaneous biopsy were sufficiently diagnostic and CT was therefore not performed (31 patients), because they had undergone only head CT due to brain metastatic disease and poor general health (ten patients), because radiation fibrosis made CT interpretation difficult (two patients), or because they had had a thoracoplasty causing gross distortion of the bronchial anatomy (one patient). The radiographic and bronchoscopic files of 66 patients were available for comparison and were included in the study. All the patients had had pretreatment chest CT scans performed. Contiguous 10 mm thick sections were obtained, from the puhnonary apices to the adrenal glands, before and after administration of intravenous infusion of contrast medium, on a Siemens Somatom 2 CT scanner. The primary lung masses were evaluated by location and the presence or absence of the ‘positive bronchus sign’. FOB was performed by an experienced respiratory physician. Visual findings were classified as follows: 1, normal; 2, mucosal abnormality without mass; 3, endobronchial mass; 4, extrinsic compression. In those patients in whom a tumour was seen, brushings and bronchial biopsies were taken. If no lesion was identified brushings and washings were obtained from regions of interest. The final diagnosis in each case was
B.V. (Biomedical
Division)
131
based on pathological material obtained from FOB, percutaneous needle biopsy, mediastinoscopy or sur-
NUMBER OF PATIENTS-V-LOCATION 30
gery.
Results 20
Eight patients had histologically proven large cell anaplastic carcinoma, six had small cell anaplastic carcinoma, 35 had squamous cell carcinoma and 17 had adenocarcinoma (Fig. 1). In ten cases (15%), a main bronchus was involved by the tumour. Carinal spread of tumour was diagnosed in six patients (9%). In 23 cases (35 %) the lesion lay within the inner one third of the pulmonary parenchyma. The location of the remaining lung tumours is shown in Fig. 2. In 82% of the cases (53 patients) a ‘positive bronchus sign’ was present on CT scan (Figs. 3 and 4 and Table I). The predictive value of a ‘positive bronchus sign was 94% (95% confidence interval: 84-992). One of the two patients who had negative cytology at FOB had positive findings on repeat investigation (initial failure due to excessive bleeding, the lesion was located in the left upper lobe). In the second patient the primary lesion was situated in the posterior divisions of the right upper lobe, and at visual FOB local reddening and oedema were reported; FOB cytology proved negative and tissue diagnosis was obtained after percutaneous needle biopsy. In 18 y0 of the cases (13 patients) no bronchus was identified on the CT slices adjacent to or within the primary lung lesion on CT (Table I). Of these 13 patients, five (38%) had positive, while eight (62%) had negative visual FOB findings. The predictive value of a ‘negative bronchus sign’ was 62 y0 (95 y0 confidence interval: 32-86%). All five patients without a positive
LCA
SCA
sea
10
0 RJL
RML
RLL
LUL
ffi
LLL
MB
LOCATION
Fig. 2. Histogram showing location of lung lesions in 66 patients; RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe; LUL, left upper lobe; LG, lingula; LLL, left lower lobe; MB, main bronchi.
Fig. 3. Narrowing
of the right main bronchus branches by a hilar mass.
(arrow)
and its
AD
HISTOLOGY
Fig. 1. Histogram showing the different tumour types; LCA, large cell anaplastic; SCA, small cell anaplastic; SQ, squamous cell; AD, adenocarcinoma.
Fig. 4. Small, air filled, bronchi seen within and in the vicinity of a well-defined mass.
132 TABLE I ‘Positive bronchus sign’ vs. bronchoscopy: tion of 66 patients with lung cancer Positive bronchus sign on CT
+ Total
agreement in the evalua-
Bronchoscopy
Total
+
-
50 5 55
3 8 11
53 13 66
bronchus sign but with positive visual FOB had positive cytology on FOB. Three of the eight patients without the positive bronchus sign and negative visual FOB, had positive washings. Five patients had an absent bronchus sign, negative visual FOB and negative cytology. In these five patients tissue diagnosis was obtained by CT-guided biopsy (two patients) or fluoroscopically guided biopsy (three patients). Discussion Survival rates after attempted curative tumour resection are reported to be considerably higher than after palliative treatment [ 51. Accurate and prompt diagnosis and staging are important in determining the most appropriate form of therapy. CT is not very helpful in the early detection of lung cancer [2,3]. Peribronchial thickening has been advocated to be an important CT sign of occult bronchogenie carcinoma, but it is often difficult to be certain of the presence of this finding as it is affected by slice thickness, observer error and bronchial orientation [4]. Some studies comparing CT and visual FOB findings for bronchial abnormalities have reported a close correlation [ 1,9,13]. Hensche et al. [ 71 reported an excellent correlation between CT and visual FOB and advised that the use of CT as an initial screening test could enhance the yield by allowing appropriate selection of patients. Nevertheless, Colice et al. [l] reported considerable interobserver variation with sensitivities ranging from 63% to 85% and suggested that radiologists should not rely on CT for identification of endobronchial lesions. It is of particular interest that in the group with a ‘negative bronchus sign’ we found six patients (46%) in whom the primary mass was located within the left upper lobe. Naidich et al. [9] also reported CT to be relatively innaccurate in the evaluation of the left bronchial tree, probably because of the oblique orientation of both the left-main stem and the lingular bronchi and suggested that this difficulty may be partially resolved by the use of thin sections.
Remy-Jardin and Remy [ 111 suggested that 20 degree oblique CT is superior to conventional scanning in the evaluation of the bronchial tree. We believe that a combination of the last two suggestions would be the most appropriate approach. The fact that the ‘positive bronchus sign’ was found in 82% of our cases compared with 54% of those of Naidich et al., despite the use of state-of-the-art equipment and thin 1.5 mm sections by the above authors, probably reflects the different populations in the two studies. Naidich et al. examined both benign and malignant nodules, whereas we confined our study to confirmed cases of bronchogenic carcinoma. The high bronchoscopic yield in our study compared to that of Naidich et al. in those patients with a ‘positive bronchus sign’ (94% vs. 60%) is probably due to the inclusion of many more central lesions in our study (35% vs. 14 %). In contrast to the above discrepancy, the figures for bronchoscopic yield in patients with a ‘negative bronchus sign’ are of the same order (38% and 30%). Nevertheless, it is noteworthy that Naidich et al. reported a much lower bronchoscopic yield (14%) in this group when thin CT sections were used. Unlike the above authors, we do not often perform densitometry of pulmonary lesions and, therefore, did not have the opportunity to evaluate the impact of thin sections on the detection of the ‘positive bronchus sign’. The fact that a ‘negative bronchus sign’ when thin CT sections are used is more strongly associated with a decreased bronchoscopic yield than is the same sign when thick sections are used suggests that any large prospective study setting out to evaluate the potential of CT in augmenting the diagnostic yield of FOB should include the use of thin CT sections. The potential of CT in the diagnosis and staging of lung cancer has not been fully explored. Studies comparing CT and mediastinoscopy in detecting mediastinal nodal involvement, reported considerable variation with sensitivity ranging from 66% to 90% [ 12,141. Patterson et al. [ 121 compared CT, MRI, plain chest radiography and mediastinoscopy as staging modalities in a prospective study and concluded that MRI was not superior to CT scanning for assessing malignant nodal involvement of the mediastinum. Mayr et al. [ 81 found CT to be superior to MRI in demonstrating endobronchial lesions. The potential of MRI for tissue characterisation has not yet been found to be clinically useful. Coronal MRI has been suggested to be useful in demonstrating lesions located in the lung apices and bases and in the aorto-pulmonary window [ 151. There is a need for a large prospective study investigating the frequency of the ‘positive bronchus sign’ in peripheral and central lung lesions of various defined
133
ranges of size. Such a study may result in clear guidelines concerning the relative indications for bronchoscopic or transthoracic biopsy, thus resulting in a decrease in the number of negative invasive procedures in patients being investigated for carcinoma of the lung. References 1 Colice GL, Chappel GJ, Frenchman SM, Solomon DA. Comparison of computerised tomography with fiberoptic bronchoscopy in identifying endobronchial abnormalities in patients with known or suspected lung cancer. Am Rev Respir Dis 1985; 13 1: 397-400. 2 Filderman AE, Shaw C, Matthay RA. Etiology, pathology, natural history, manifestations and diagnostic techniques in lung cancer. Part I. Invest Radio1 1986; 21: 80-90. 3 Filderman AE, Shaw C, Matthay RA. Lung cancer. Part II. Staging and therapy. Invest Radio1 1986; 21: 173-185. 4 Foster WL Jr, Roberts L Jr, McLendon RE, Hill RC. Localised peribronchial thickening: a CT sign of occult bronchogenic carcinoma. AJR 1985; 144: 906-908. 5 Frank AL. The epidemiology and etiology of lung cancer. Clin Chest Med 1982; 5: 219-228. 6 Fulkerson WJ. Current concepts: fiberoptic bronchoscopy. N Engl J Med 1984; 311: 511-516. 7 Henschke CI, Davis SD, Auh Y, Roman0 P, Westcott J, Berkmen YM, Kazam E. Detection of bronchial abnormalities: comparison of CT and bronchoscopy. J Comp Assist Tomogr 1987: 11: 432-435.
8 Mayr B, Heywang SH, Ingrisch H, Huber RM, Haussinger K, Lissner J. Comparison of CT with MR imaging of endobronchial tumors. J Comp Assist Tomogr 1987; 11: 43-48. 9 Naidich DP, Jen-Jyh Lee, Garay SM, McCauley DI, Aranda CP. Boyd AD. Comparison ofCT and fiberoptic bronchoscopy in the evaluation of bronchial disease. AJR 1987; 148: l-7. 10 Naidich DP, Sussman R, Kutcher WL, Aranda CP, Garay SM, Ettenger NA. Solitary pulmonary nodules. CT-bronchoscopic correlation. Chest 1988; 93: 595-598. 11 Remy-Jardin M, Remy J. Comparison of vertical and oblique in evaluation of bronchial tree. J Comp Assist Tomogr 1988; 12: 956-962. 12 Patterson GA, Ginsberg RJ, Poon PY, Cooper JD, Goldberg M, Jones D, Pearson FG, Todd TR, Waters P, Bull S. A prospective evaluation magnetic resonance imaging, computed tomography, and mediastinoscopy in the preoperative assessment of mediastinal node status in bronchogenic carcinoma. J Thorac Cardiovasc Surg 1987; 94: 679-684. 13 Rollandi GA, Ratto GB, Mereu C, Castagnola M, Colamartino S, Sacco A, Motta G. Evaluation ofhilar and mediastinal lymph nodes in lung cancer patients by bronchoscopy and computed tomography. Panminerva Med 1986; 28: 241-242. 14 Staples CA, Muller NL, Miller RR, Evans KG, Nelems B. Mediastinal nodes in brochogenic carcinoma: comparison between CT and mediastinoscopy. Radiology 1988; 167: 367-372. 15 Webb WR, Densen BG, Gamsu G. Sag&al MR imaging of the chest: normal and abnormal. J Comp Assist Tomogr 1985; 9: 471.
130
EURRAD
00021
The positive bronchus sign in patients with known lung cancer G. Zacharopoulos
‘, A. Adam’
and P.W. Ind2
Departments of ‘DiagnosticRadiology and ‘Medicine. Royal PostgraduateMedical School, Hammersmith Hospital, London, U.K. (Received 29 September
Key words: Computed
1989; accepted
tomography,
13 October
chest; Bronchoscopy;
1989)
Lung cancer, CT
Abstract The positive bronchus sign is the CT finding of a bronchus leading to or contained within the primary mass. A prospective study was performed for the purpose of establishing the correlation between the above sign on CT and the visual and pathological tindings on bronchoscopy. The predictive value for the positive bronchus sign was found to be 94% and that of the negative bronchus sign 62%. CT is useful in predicting the likelihood of subsequent bronchoscopy providing positive results.
Introduction Lung cancer is a leading cause of death in men and women [2,5]. Computerized tomography (CT) and fiberoptic bronchoscopy (FOB) are extensively used in the assessment of patients with known or suspected lung cancer [ 51. Although recent studies report very good correlation between CT and both visual and pathological FOB findings [ 1,7] it is not known whether CT can increase the diagnostic yield of FOB with regard to the primary tumour. A ‘positive bronchus sign’, the CT finding of a bronchus leading to or contained within the nodule or mass, has been claimed to be very useful in the routine evaluation of pulmonary nodules prior to FOB, since the likelihood of obtaining a diagnostic cytological specimen from FOB is significantly increased if the sign is present [ lo]. The aim of this study was to establish the agreement between the ‘positive bronchus sign’ and the yield of FOB in patients with known lung cancer. Patients and Methods The records of 110 patients with documented lung cancer who had been investigated at Hammersmith Address for reprints: Dr. G. Zacharopoulos, Diagnostic Radiology, Hammersmith Hospital, London W12 OHS, U.K. 0720-048X/90/$03.50
Department of Du Cane Road,
0 1990 Elsevier Science Publishers
Hospital were evaluated retrospectively. Forty-four patients were excluded from the study, because plain chest radiography, FOB and/or percutaneous biopsy were sufficiently diagnostic and CT was therefore not performed (31 patients), because they had undergone only head CT due to brain metastatic disease and poor general health (ten patients), because radiation fibrosis made CT interpretation difficult (two patients), or because they had had a thoracoplasty causing gross distortion of the bronchial anatomy (one patient). The radiographic and bronchoscopic files of 66 patients were available for comparison and were included in the study. All the patients had had pretreatment chest CT scans performed. Contiguous 10 mm thick sections were obtained, from the puhnonary apices to the adrenal glands, before and after administration of intravenous infusion of contrast medium, on a Siemens Somatom 2 CT scanner. The primary lung masses were evaluated by location and the presence or absence of the ‘positive bronchus sign’. FOB was performed by an experienced respiratory physician. Visual findings were classified as follows: 1, normal; 2, mucosal abnormality without mass; 3, endobronchial mass; 4, extrinsic compression. In those patients in whom a tumour was seen, brushings and bronchial biopsies were taken. If no lesion was identified brushings and washings were obtained from regions of interest. The final diagnosis in each case was
B.V. (Biomedical
Division)
131
based on pathological material obtained from FOB, percutaneous needle biopsy, mediastinoscopy or sur-
NUMBER OF PATIENTS-V-LOCATION 30
gery.
Results 20
Eight patients had histologically proven large cell anaplastic carcinoma, six had small cell anaplastic carcinoma, 35 had squamous cell carcinoma and 17 had adenocarcinoma (Fig. 1). In ten cases (15%), a main bronchus was involved by the tumour. Carinal spread of tumour was diagnosed in six patients (9%). In 23 cases (35 %) the lesion lay within the inner one third of the pulmonary parenchyma. The location of the remaining lung tumours is shown in Fig. 2. In 82% of the cases (53 patients) a ‘positive bronchus sign’ was present on CT scan (Figs. 3 and 4 and Table I). The predictive value of a ‘positive bronchus sign was 94% (95% confidence interval: 84-992). One of the two patients who had negative cytology at FOB had positive findings on repeat investigation (initial failure due to excessive bleeding, the lesion was located in the left upper lobe). In the second patient the primary lesion was situated in the posterior divisions of the right upper lobe, and at visual FOB local reddening and oedema were reported; FOB cytology proved negative and tissue diagnosis was obtained after percutaneous needle biopsy. In 18 y0 of the cases (13 patients) no bronchus was identified on the CT slices adjacent to or within the primary lung lesion on CT (Table I). Of these 13 patients, five (38%) had positive, while eight (62%) had negative visual FOB findings. The predictive value of a ‘negative bronchus sign’ was 62 y0 (95 y0 confidence interval: 32-86%). All five patients without a positive
LCA
SCA
sea
10
0 RJL
RML
RLL
LUL
ffi
LLL
MB
LOCATION
Fig. 2. Histogram showing location of lung lesions in 66 patients; RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe; LUL, left upper lobe; LG, lingula; LLL, left lower lobe; MB, main bronchi.
Fig. 3. Narrowing
of the right main bronchus branches by a hilar mass.
(arrow)
and its
AD
HISTOLOGY
Fig. 1. Histogram showing the different tumour types; LCA, large cell anaplastic; SCA, small cell anaplastic; SQ, squamous cell; AD, adenocarcinoma.
Fig. 4. Small, air filled, bronchi seen within and in the vicinity of a well-defined mass.
132 TABLE I ‘Positive bronchus sign’ vs. bronchoscopy: tion of 66 patients with lung cancer Positive bronchus sign on CT
+ Total
agreement in the evalua-
Bronchoscopy
Total
+
-
50 5 55
3 8 11
53 13 66
bronchus sign but with positive visual FOB had positive cytology on FOB. Three of the eight patients without the positive bronchus sign and negative visual FOB, had positive washings. Five patients had an absent bronchus sign, negative visual FOB and negative cytology. In these five patients tissue diagnosis was obtained by CT-guided biopsy (two patients) or fluoroscopically guided biopsy (three patients). Discussion Survival rates after attempted curative tumour resection are reported to be considerably higher than after palliative treatment [ 51. Accurate and prompt diagnosis and staging are important in determining the most appropriate form of therapy. CT is not very helpful in the early detection of lung cancer [2,3]. Peribronchial thickening has been advocated to be an important CT sign of occult bronchogenie carcinoma, but it is often difficult to be certain of the presence of this finding as it is affected by slice thickness, observer error and bronchial orientation [4]. Some studies comparing CT and visual FOB findings for bronchial abnormalities have reported a close correlation [ 1,9,13]. Hensche et al. [ 71 reported an excellent correlation between CT and visual FOB and advised that the use of CT as an initial screening test could enhance the yield by allowing appropriate selection of patients. Nevertheless, Colice et al. [l] reported considerable interobserver variation with sensitivities ranging from 63% to 85% and suggested that radiologists should not rely on CT for identification of endobronchial lesions. It is of particular interest that in the group with a ‘negative bronchus sign’ we found six patients (46%) in whom the primary mass was located within the left upper lobe. Naidich et al. [9] also reported CT to be relatively innaccurate in the evaluation of the left bronchial tree, probably because of the oblique orientation of both the left-main stem and the lingular bronchi and suggested that this difficulty may be partially resolved by the use of thin sections.
Remy-Jardin and Remy [ 111 suggested that 20 degree oblique CT is superior to conventional scanning in the evaluation of the bronchial tree. We believe that a combination of the last two suggestions would be the most appropriate approach. The fact that the ‘positive bronchus sign’ was found in 82% of our cases compared with 54% of those of Naidich et al., despite the use of state-of-the-art equipment and thin 1.5 mm sections by the above authors, probably reflects the different populations in the two studies. Naidich et al. examined both benign and malignant nodules, whereas we confined our study to confirmed cases of bronchogenic carcinoma. The high bronchoscopic yield in our study compared to that of Naidich et al. in those patients with a ‘positive bronchus sign’ (94% vs. 60%) is probably due to the inclusion of many more central lesions in our study (35% vs. 14 %). In contrast to the above discrepancy, the figures for bronchoscopic yield in patients with a ‘negative bronchus sign’ are of the same order (38% and 30%). Nevertheless, it is noteworthy that Naidich et al. reported a much lower bronchoscopic yield (14%) in this group when thin CT sections were used. Unlike the above authors, we do not often perform densitometry of pulmonary lesions and, therefore, did not have the opportunity to evaluate the impact of thin sections on the detection of the ‘positive bronchus sign’. The fact that a ‘negative bronchus sign’ when thin CT sections are used is more strongly associated with a decreased bronchoscopic yield than is the same sign when thick sections are used suggests that any large prospective study setting out to evaluate the potential of CT in augmenting the diagnostic yield of FOB should include the use of thin CT sections. The potential of CT in the diagnosis and staging of lung cancer has not been fully explored. Studies comparing CT and mediastinoscopy in detecting mediastinal nodal involvement, reported considerable variation with sensitivity ranging from 66% to 90% [ 12,141. Patterson et al. [ 121 compared CT, MRI, plain chest radiography and mediastinoscopy as staging modalities in a prospective study and concluded that MRI was not superior to CT scanning for assessing malignant nodal involvement of the mediastinum. Mayr et al. [ 81 found CT to be superior to MRI in demonstrating endobronchial lesions. The potential of MRI for tissue characterisation has not yet been found to be clinically useful. Coronal MRI has been suggested to be useful in demonstrating lesions located in the lung apices and bases and in the aorto-pulmonary window [ 151. There is a need for a large prospective study investigating the frequency of the ‘positive bronchus sign’ in peripheral and central lung lesions of various defined
133
ranges of size. Such a study may result in clear guidelines concerning the relative indications for bronchoscopic or transthoracic biopsy, thus resulting in a decrease in the number of negative invasive procedures in patients being investigated for carcinoma of the lung. References 1 Colice GL, Chappel GJ, Frenchman SM, Solomon DA. Comparison of computerised tomography with fiberoptic bronchoscopy in identifying endobronchial abnormalities in patients with known or suspected lung cancer. Am Rev Respir Dis 1985; 13 1: 397-400. 2 Filderman AE, Shaw C, Matthay RA. Etiology, pathology, natural history, manifestations and diagnostic techniques in lung cancer. Part I. Invest Radio1 1986; 21: 80-90. 3 Filderman AE, Shaw C, Matthay RA. Lung cancer. Part II. Staging and therapy. Invest Radio1 1986; 21: 173-185. 4 Foster WL Jr, Roberts L Jr, McLendon RE, Hill RC. Localised peribronchial thickening: a CT sign of occult bronchogenic carcinoma. AJR 1985; 144: 906-908. 5 Frank AL. The epidemiology and etiology of lung cancer. Clin Chest Med 1982; 5: 219-228. 6 Fulkerson WJ. Current concepts: fiberoptic bronchoscopy. N Engl J Med 1984; 311: 511-516. 7 Henschke CI, Davis SD, Auh Y, Roman0 P, Westcott J, Berkmen YM, Kazam E. Detection of bronchial abnormalities: comparison of CT and bronchoscopy. J Comp Assist Tomogr 1987: 11: 432-435.
8 Mayr B, Heywang SH, Ingrisch H, Huber RM, Haussinger K, Lissner J. Comparison of CT with MR imaging of endobronchial tumors. J Comp Assist Tomogr 1987; 11: 43-48. 9 Naidich DP, Jen-Jyh Lee, Garay SM, McCauley DI, Aranda CP. Boyd AD. Comparison ofCT and fiberoptic bronchoscopy in the evaluation of bronchial disease. AJR 1987; 148: l-7. 10 Naidich DP, Sussman R, Kutcher WL, Aranda CP, Garay SM, Ettenger NA. Solitary pulmonary nodules. CT-bronchoscopic correlation. Chest 1988; 93: 595-598. 11 Remy-Jardin M, Remy J. Comparison of vertical and oblique in evaluation of bronchial tree. J Comp Assist Tomogr 1988; 12: 956-962. 12 Patterson GA, Ginsberg RJ, Poon PY, Cooper JD, Goldberg M, Jones D, Pearson FG, Todd TR, Waters P, Bull S. A prospective evaluation magnetic resonance imaging, computed tomography, and mediastinoscopy in the preoperative assessment of mediastinal node status in bronchogenic carcinoma. J Thorac Cardiovasc Surg 1987; 94: 679-684. 13 Rollandi GA, Ratto GB, Mereu C, Castagnola M, Colamartino S, Sacco A, Motta G. Evaluation ofhilar and mediastinal lymph nodes in lung cancer patients by bronchoscopy and computed tomography. Panminerva Med 1986; 28: 241-242. 14 Staples CA, Muller NL, Miller RR, Evans KG, Nelems B. Mediastinal nodes in brochogenic carcinoma: comparison between CT and mediastinoscopy. Radiology 1988; 167: 367-372. 15 Webb WR, Densen BG, Gamsu G. Sag&al MR imaging of the chest: normal and abnormal. J Comp Assist Tomogr 1985; 9: 471.
