Thorax 1985;40:920-924

Assessment of bronchiectasis by computedtomographyIM MOOTOOSAMY, RH REZNEK, J OSMAN, RSO REES, MALCOLM GREEN

From the Departments of Diagnostic Radiology and Chest Medicine, St Bartholomew's Hospital, London

ABSTRACT Computed tomography and bronchography were used to assess the distribution ofbronchiectasis in 15 lungs from eight patients with clinical features of the disease. Of the 36 lobesadequately displayed by bronchography, 22 were found to have bronchiectasis and 14 were foundto be normal by both techniques. Cystic disease was readily identified by computed tomography butthe cylindrical and varicose types of bronchiectasis could not be distinguished. Segmental local-isation was less accurate, with agreement between computed tomography and bronchography in 116out of 130 segments. It is concluded that with a modern high resolution scanner computed tom-ography provides a useful method of assessing lobar distribution in bronchiectasis.

The incidence of bronchiectasis in the United King-dom has decreased since the advent of antibiotic treat-ment and the decline in severe respiratory disease inchildhood. Nevertheless, it still occurs as the result ofsevere pulmonary infections and in association withimmune deficiency, cystic fibrosis, and other condi-tions.The disease is defined as irreversible abnormal di-

latation of the bronchi and has been classified byReid' into three types-cystic, varicose, andcylindri-cal. Although the plain chest film may provide a clue,particularly in the cystic type, bronchography is stillthe definitive investigation. It is indicated when it isnecessary to confirm the clinical diagnosis or, if thedisease is localised, to exclude the disease in otherparts of the lungs if lobectomy is contemplated. Bron-chography is an unpleasant, potentially dangerous,23and invasive investigation that requires considerableskill and even when expertly performed it may leaveareas of lung inadequately examined owing to tech-nical or other difficulties.Computed tomography scanners with their im-

proved resolution provide a potential means of de-tecting or excluding bronchiectasis and so avoidingbronchography. Naidich et al4 described the appear-ances of bronchiectasis on computed tomography insix patients and recently Muller et al presented re-sults obtained in 11 patients. Whereas Naidich et alwere optimistic about computed tomography re-

Address for reprint requests: Dr IM Mootoosamy, Department ofDiagnostic Radiology, St Bartholomew's Hospital, LondonECIA 7BE.

Accepted 8 July 1985

placing bronchography in a substantial number,Muller et al found correspondence in only about halfthe lungs studied.The purpose of this study is to assess the place of

modern high resolution computed tomography scan-ners in the clinical management of patients with bron-chiectasis and to investigate the accuracy with whichlobar and segmental disease and the type of diseasepresent can be predicted.

Patients and methods

Eight patients with a clinical diagnosis of bronchi-ectasis were included in the study, all of whom hadposteroanterior, lateral, and supine chest films; bron-chograms; and computed tomography scans. Bilateralbronchograms were obtained in seven of the patients(aqueous dionosil being used), three via a fibreopticbronchoscope and four by transnasal tracheal intu-bation. In one patient a right bronchogram only wasavailable as the examination had to be abandonedbefore the left side was examined owing to thepatient's distress.Computed tomography scans were performed with

a GE 9800 scanner with a two second scan time, 512matrix, and 10mm scan thickness. The patients wereexamined supine with slices at I cm intervals throughthe lungs. Scans were also obtained with the patientprone where indicated to differentiate dependent pul-monary vessels. The interval between computed tom-ography and bronchography was less than six monthsin all patients except patient I (with cystic bronchi-ectasis), who was scanned at 12 months.The chest radiographs were examined indepen-

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Assessment of bronchiectasis by computed tomography

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Fig 1 (Above) Computed tomography scan of lungsshowing bronchial wall thickening and dilatation in bothlower lobes, with "tramline" appearance in the rightanterior segment and in the left lower lobe (arrowed).

(Right) Bronchogram from the same patient: oblique viewof right lower lobe showing bronchial dilatation.

dently by one radiologist (RSOR) without knowledgeof other findings. The lobar distribution of changesconsistent with bronchiectasis was recorded from theplain films. The presence of bronchiectasis as seen on

bronchography was recorded to include its type (cys-tic, varicose, or cylindrical), lobar distribution withineach lung, and, within each lobe, disease of individualsegments. The computed tomography scans were as-

Fig 2 Computed tomography scan oflungs showing bronchial dilatation andbronchial wall thickening in the leftlower lobe and in the lingula(arrowed). A dilated, thick walledbronchus cut transversely is seen in theposterior segment of the left lowerlobe as a circular lucency (openarrow).

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Comparison of results of computed tomography and bronchography

Patient 1 2 3 4 5 6 7 8

CT B CT B CT B CT B CT B CT B CT B CT B

Right upper lobeApical - v. . . . . . .- - -Posterior +Anterior + v. . . . . . . . . - - - -Right middle lobeMedial + + - - c + - - + + + v + *Lateral + + - - + + - -..+ v - *Right lower lobe )Apical c cMedial c c + + + + - + v - +Anterior c c - - 0 + - v + vLateral c e - + - + + +- -vPosterior c c + v + + + v + + + v + +Left upper lobeApical + - -Antenor -Superior lingula + + v - - - - + - oInferiorlingula * v - - - - + + + +Left lower lobe 0Apical - v *Posterior + v + + + * + + + + + + + + XLateral + v + + + * + - + + + + + +Anterior - v * + + + + + + Zz X

CT = computed tomography scan; B = bronchogram; + = cylindrical bronchiectasis; v = varicose bronchiectasis; c = cystic bronchiectasis;- = normal; 0 = consolidation; * = underfilling; ® = lobes where bronchiectasis changes seen on plain radiograph.

sessed independently by another radiologist (RHR),also without knowledge of other findings.Normal bronchi can be seen on computed tom-

ography only in the central portions ofthe lung paren-chyma in or adjacent to the hila."6 The peribronchialfibrosis, however, associated with bronchiectasis6with resultant bronchial wall thickening and di-latation renders bronchi visible in more peripheralparts of the lung,6 and thickening of the wall com-bined with the lack of peripheral tapering suggests thediagnosis. When cut longitudinally these abnormalbronchi appear as "tramlines" (fig la). When cuttransversely they appear as circular or oval lucencies(fig 2) and the lack of tapering can be confirmed byexamination of two or more contiguous slices. In thecylindrical type of disease the walls have a smoothoutline, whereas in the varicose type they are said tohave a "beaded" appearance.6 Cystic disease isreadily recognisable on computed tomography, thecysts being arranged in clusters or strings.The presence or absence of bronchiectasis on the

computed tomography scans was recorded accordingto these criteria, and after the lobar distribution andthe type of disease had been established an attemptwas made to predict whether particular segments wereaffected within each lobe. On computed tomography,pulmonary lobes can be recognised easily by locatingthe main fissures.78 Segmental anatomy, although notso easy, can be identified by locating the segmentalbronchi and pulmonary vessels.89

Results

The chest radiographs were thought to be normal infive patients and to show changes consistent withbronchiectasis in three. Patient I showed cysticchanges in the right lower lobe, patient 6 showedtramline shadows in the left lower lobe, and patient 7showed tramline shadows in the right middle andlower lobes (table).

Bronchography was performed in eight patients; inone patient only one side could be examined, so that15 lungs were available for comparison. Part of themiddle lobe was underfilled in one patient and part ofthe left lower lobe in another; of the 36 remaininglobes, 22 were assessed as showing evidence of bron-chiectasis and 14 were normal. Independent assess-ment of the computed tomography scans indicatedthat the same 22 lobes showed bronchiectasis, whilethe other 14 were considered to be free of disease. Thetwo lobes that were underfilled in the bronchogramalso showed evidence of disease on computed tom-ography. There was extensive cystic disease in theright lower lobe of one patient, which was obvious onbronchography (fig 3a). This correlated well with thecomputed tomography findings (fig 3b). Otherwise thedisease appeared on the bronchograms to be mostly ofthe cylindrical type, but varicose changes were notedin some parts of six lobes. The differences betweenvaricose and cylindrical bronchiectasis could not bedistinguished on computed tomography. Thus there

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Assessment of bronchiectasis by computed tomography

Fig 3 (a) Right lung bronchogram showing cysticbronchiectasis in the right lower lobe corresponding with thecomputed tomography appearances.

was concordance between the results of bron-chography and computed tomography in the assess-ment of lobar disease by two independent observerswithout knowledge of each other's findings.Agreement about segmental localisation was less

good. There was agreement on the presence or ab-sence of disease in 116 of the 130 segments: 74 werenormal, and 42 abnormal. In 14 there was disagree-ment. Bronchiectasis could not be diagnosed on com-puted tomography scans in 10 of these segments(although present elsewhere in the lobe), but wasthought to be present on the bronchograms; in two ofthese there was consolidation in which bronchiectasiscould not be diagnosed. In four segments disease wasattributed to a segment on the computed tomographyscan but not seen in that segment on the bron-chogram.

(b) Computed tomography scan of right lower lobe showingcystic bronchiectasis; there is also loss of volume.

Discussion

There appears to be no dispute that cystic bronchi-ectasis which is usually visible on the plain chest film,can be detected as readily by computed tomographyas by bronchography.45 The results of this studysuggest that cylindrical or varicose disease can also bedetected or excluded on the modern scanner, as thecorrelation between computed tomography scan andbronchogram in assessing whether lobes were affectedby bronchiectasis was excellent.

Localisation of bronchiectatic segments gave fourfalse positive and 10 false negative results from com-puted tomography of a total of 130 segments. Sub-sequent review of these differences showed that theywere due to problems in defining segmental anatomyin both techniques, distortion from fibrosis, and, per-

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haps most importantly, consolidation that concealeddilated bronchi within it. Although the bronchogramis widely accepted as the gold standard in the diagno-sis of bronchiectasis, it may fail to provide informa-tion about some of the bronchial tree. In this series theexamination was incomplete in two of the eight pa-tients. In the patient with the unilateral bronchogramextensive bronchiectasis was seen on the computedtomography scan in a lower lobe of the lung not exam-ined by bronchography (fig 2) because of the patient'sextreme discomfort. In the series of Muller et al bilat-eral bronchograms were available for comparison inonly four out of nine patients, although the reasonsfor this are not stated. Such technical failures are rarewith computed tomography.

Naidich et al4 found good correlation betweencomputed tomography and bronchography in thefour patients they examined by these two techniques;our results are similar. Muller et al5 compared com-puted tomography and bronchography in 13 lungs,and found good agreement between the assessment interms of the extent and severity of bronchiectasis inonly six. These differences could be due to the use byus of a high definition scanner and perhaps higherspecificity of interpretation.

There appear to be two clinical indications for per-forming bronchography: firstly, it may be considerednecessary to confirm a clinical diagnosis. These resultsclearly suggest that computed tomography should bethe initial method of choice and that no importantdegree of lobar disease will be missed. Secondly, pa-tients with localised disease may benefit from lobec-tomy provided that disease in other areas of the lungscan be confidently excluded. This study shows thatbronchiectasis of any one lobe was not missed bycomputed tomography and that lobar disease seen ona scan was confirmed by bronchography. Segmentallocalisation was less accurate but this degree of detail

Mootoosamy, Reznek, Osman, Rees, Green

is not usually relevant clinically.We conclude that computed tomography with a

modern high resolution scanner is an acceptable alter-native to bronchography in assessing lobar distribu-tion of bronchiectasis in patients with clinical featuresof this disease.

We are grateful to the special trustees of St Bar-tholomew's Hospital for their generosity in purchas-ing the computed tomography scanner. We wouldalso like to thank Dr I Kelsey Fry for his help andadvice, and Julie Jessop for her secretarial assistance.

References

I Reid LMcA. Reduction in bronchial subdivision in bron-chiectasis. Thorax 1950;5:233-47.

2 Ansell G. Complications in diagnostic radiology. Ist ed.Oxford: Blackwell Scientific Publications, 1976:287, 289.

3 Olsen AM, O'Neill JJ. Bronchography-a report of theCommittee of Bronchoesophagology, American Collegeof Chest Physicians. Dis Chest 1967;51:663-8.

4 Naidich DP, McCauley DI, Khouri NF, Stitik FP, Sie-gelman SS. Computed tomography of bronchiectasis. JComput Assist Tomogr 1982;6:437-44.

5 Muller NL, Bergin CJ, Ostravo DN, Nichols DM. Roleof CT in recognition of bronchiectasis. AJR1984;143:971-6.

6 Naidich DP, Zerhouni EA, Siegelman SS. Computedtomography of the thorax. 1st ed. New York: RavenPress, 1984:104-5.

7 Sagel SS, Aronberg DJ. CT body tomography. 1st ed.New York: Raven Press, 1982:64-5.

8 Osborne D, Vock P, Godwin JD, Silverman PM. CTidentification of bronchopulmonary segments: 50 normalsubjects. AJR 1984;142:47-52.

9 Naidich DP, Terry PB, Stitik FP, Siegelman SS. CT ofthe bronchi. 1. Normal anatomy. J Comput AssistTomogr 1980;4:746-53.

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