Assessing the role of routine chest radiography in asymptomatic students during registration at a university in an endemic area of tuberculosis


Context: Routine chest radiographs are usually obtained from asymptomatic individuals during routine medical visits probably to detect the presence of occult disease. In sub-Saharan countries tuberculosis is endemic among young individuals; primary tuberculosis might be the most probable occult disease sought for. Aims: The aim was to determine the diagnostic yield and cost-effectiveness of routine chest radiography in an asymptomatic student population in Yaounde during registration at a university. Settings and Design: A cross-sectional descriptive study carried out in a University-affiliated hospital in Yaounde, Cameroon. Materials and Methods: Postero-anterior (PA) chest radiographs were obtained from students during a routine medical visit before university admission. Radiographic results were coded as normal, minor, or major findings. The estimated cost per radiograph was that of the study setting at the time of the study. Statistical Analysis Used: Epi Info software version 3.3.2 of February 9 2005 (CDC Atlanta) was used for statistical analysis. Results: Of 758 students enrolled, there were 280 males and 478 females (sex ratio 1:2). The mean age of the study population was 21 years (age range 15-33 years). All enrolled cases were asymptomatic. There were 739 normal radiographs (97.5%), while 19 radiographs (2.5 %) showed minor abnormalities. No major abnormality was seen. The estimated direct cost of all the radiographs obtained was 3,941,600 F CFA ($ 8,760). Conclusions: Routine chest radiography has a low diagnostic yield in asymptomatic students even in a setting where tuberculosis is endemic, and is therefore not cost-effective.

Keywords: Primary Tuberculosis, Routine Chest Radiography, Routine Medical Visit, Student Registration

How to cite this article:
Boniface M, Joshua T, Walter PE, Fernande ZO, Emrick GK, Joseph GF. Assessing the role of routine chest radiography in asymptomatic students during registration at a university in an endemic area of tuberculosis. Ann Trop Med Public Health 2012;5:419-22
How to cite this URL:
Boniface M, Joshua T, Walter PE, Fernande ZO, Emrick GK, Joseph GF. Assessing the role of routine chest radiography in asymptomatic students during registration at a university in an endemic area of tuberculosis. Ann Trop Med Public Health [serial online] 2012 [cited 2020 Nov 24];5:419-22. Available from:

Chest radiography plays an important role in patient care and is usually the first imaging modality for the assessment of thoracic pathologies, partly owing to the fact that it is widely available and also fairly accessible. It also provides very useful information that can be sufficiently life saving. However, routine chest radiography has been shown to have a low diagnostic yield in asymptomatic hospitalized patients. [1],[2],[3],[4] In some health institutions routine chest radiographs are obtained as part of preoperative work-up. It is also recommended by some employees during preemployment medical check-up and by some educational institutions during registration of potential candidates. This is supposedly done in order to detect the presence of any occult disease.

Among asymptomatic University students in a setting like ours, primary tuberculosis might well be the most probable occult disease sought for, and chest radiography remains the mainstay for radiological diagnosis. [5] Estimates of the epidemiological burden of tuberculosis in Cameroon in 2007 revealed a prevalence of 195 cases per 100 000 inhabitants. [6] Primary tuberculosis is self-limiting and may be asymptomatic for a while, [5] and because it is perceived to be a childhood disease, it is not often suspected in adults. [7] In this setting then routine chest radiographs will therefore seek to depict any finding that may be suggestive of tuberculosis. Radiation exposure even though to be negligible with a modern chest radiography must be considered especially in the young population of students, as well as the cost of the procedure in developing countries.

Though routine chest radiography remains common practice in some places, like our study milieu, some studies conducted elsewhere indicated that the likelihood of detecting any treatable cardiopulmonary disease is low. [8],[9] We therefore decided to carry out this study so as to evaluate the relevance of routine radiographic screening of young asymptomatic individuals from a public health point of view. The main aim was to determine the diagnostic yield and cost-effectiveness of routine chest radiography in an asymptomatic student population.

Materials and Methods

We carried out a cross-sectional descriptive study at the Gynaeco-Obstetric and Paediatric Hospital Yaounde, a University-affiliated hospital. The study was carried out during the month of December 2010, a period during which some prospective university students were undergoing a routine medical visit (which also comprised a routine chest radiographic screening) as part of university registration requirements.

Initial consultation was carried out at the Emergency Unit by General Practitioners to screen for any underlying illness and also to assess past medical history. A PA chest radiograph was then obtained at the Diagnostic Radiology Unit upon presentation of a request form the Emergency Unit that contained the following information; name, age, gender, and clinical findings. The quality of the radiographs was first checked by radiology residents and final interpretation of the radiographs was done with the aid of a view box by two consultant radiologists with more than 5 years of experience in the interpretation of chest radiographs. Radiographic results were coded as normal, minor, or major abnormalities. The minor abnormalities included findings which required no further investigation such as costo-phrenic angle blunting of pleural scarring, parenchymal scarring, alveolar opacities, isolated increased cardiac silhouette. Major abnormalities would include any finding that will require further investigations, such as the presence of a pulmonary nodule or suspicious pulmonary or mediastinal opacities. The evaluated cost was that of single-view conventional PA chest radiograph at this hospital at the time of the study. Expenditures such as consultation fee or other expenses incurred by the institution or the students regarding the screening exercise were not evaluated. The local currency, the Communauté Financière Africaine franc (F CFA) was used to determine the cost and then converted to United States dollars ($) using the exchange rate as at the time of the study.

Data were collected with the aid of a standardized questionnaire. Statistical analysis was performed using the software Epi Info version 3.3.2 of February 9 2005 (CDC Atlanta).


A total of 758 students were enrolled. There were 280 males and 478 females, giving a sex ratio of 1:2. The mean age of the study population was 20.9 years, with a minimum age of 15 years and a maximum of 33 years.

All enrolled cases were asymptomatic for chest pathology as on the day of consultation and the taking of the chest radiograph. Ten (10) cases of occasional cigarette smoking were declared (all were males).

Of the 758 radiographs obtained, 739 radiographs were normal (97.5%), while 19 radiographs (2.5 %) revealed some minor abnormalities. No major abnormality was encountered. [Table 1] and [Table 2] show the various minor abnormalities encountered. [Figure 1] and [Figure 2] show two examples with minor abnormalities encountered.

Figure 1: Close-up chest radiograph. Linear opacities of the right upper lobe

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Figure 2: Close-up chest radiograph. Blunting of the right costo-phrenic angle due to pleural scarring

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Table 1: Minor abnormalities among males

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Table 2: Minor abnormalities among females

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Six (0.8%) of the minor abnormalities were found in males while 13 (1.7%) were found in females. Two (02) radiographs were suggestive of evolving lung parenchymal processes (alveolar opacities), and all were found in females.

The cost of a single-view PA chest radiograph at the Yaounde Gynaeco-Obstetric and Paediatric Hospital at the time of the study was 5 200 F CFA ($ 11.5). The direct cost of all the 758 radiographs obtained was estimated at obtained was 3,941,600 F CFA ($ 8,760).


About two-thirds of our study population were females, probably explained by the fact that males of the same age group usually indulge in risky activities and hobbies, and also an increased rate of school attendance by females. With a study population mean age of 21 years, we think this perfectly represents most undergraduate University student populations.

No major abnormality was observed in any radiograph. Our findings were consistent with that obtained by Tigges et al.[4] who evaluated the diagnostic yield of chest radiographs in asymptomatic primary care patients, and no patient younger than 40 years had a major abnormality.

It is likely that chest radiographs were obtained from these healthy patients to detect any occult disease such as lung cancer as early as possible so that cure can be possible, even though chest radiography has been found to have a poor sensitivity for the detection of lung cancer. [10] Some studies have shown no benefit in screening even a high-risk group such as smokers for lung cancer using radiography. [11],[12] Our student population with a mean age of 21 years does not particularly seem to be at risk for lung cancer. We would also not expect to find traces of industrial dust diseases among such a young and unexposed group. Also, even if some of these students might have been exposed to the germ Mycobacterium tuberculosis, normal chest radiographs have been demonstrated in up to 15% of patients with proved tuberculosis. [13]

The two radiographs with alveolar opacities were suggestive of active treatable lung parenchymal processes. This indicates the possibility that some students might be having some mild evolving lung parenchymal processes at the time a routine medical visit is required.

Physically active healthy young individuals involved in highly competitive sporting activities might have a physiologic enlarged cardiac silhouette.

Radiation exposure should always be taken into consideration each time ionizing radiation is to be used, with the benefits over potential risks carefully considered. If the benefits are outweighed by potential risks then the procedure might as well be given a second thought. The cost-effectiveness of any diagnostic radiology procedure also has to be carefully considered especially in a low-resource setting like ours, for the spending of resources in procedures known to have a low diagnostic yield would not be cost-effective.

Some limitations were however encountered during this study, including the fact that only single-view chest radiographs were obtained, and no previous or further investigations were available for the students whose radiographs showed some parenchymal changes which we considered of no grave pathologic consequence based on radiological presentation alone. We could not therefore rule out previous tuberculosis among those with apical opacities neither could we confirm the nontuberculous nature of the alveolar opacities.


With most of the chest radiographs being normal and no major abnormality being depicted, this study shows that routine chest radiography in an asymptomatic student population has a low diagnostic yield and consequently not cost-effective in a resource-limited setting. Perhaps these would be improved if the radiographs were obtained from persons who are symptomatic during a routine medical visit or have past history of chronic lung infections.


Our thanks to the following personnel of the Yaounde Gynaeco-Obstetric and Paediatric Hospital: the staff of the Emergency Department, especially Drs. Ndema and Nkeudjoua for the initial clinical examination of the students and their close collaboration with the investigators, the radiographers of the Radiology Department for the quality of the radiographs, the Head of Radiology Department (Pr Gonsu) for his support.

1. Aronson S, Gennis P, Kelly D, Landis R, Gallagher J. The value of routine admission chest radiographs in adult asthmatics. Ann Emerg Med 1989;18:1206-8.
2. Farnsworth PB, Steiner EK, SanFilippo JA. The value of routine preoperative chest roentgenograms in infants and children. JAMA 1980;244:582-3.
3. Hubbell FA, Greenfield S, Tyler JL, Chetty K, Wyle FA. The impact of routine admission chest radiograph films on patient care. N Engl J Med 1985;312:209-13.
4. Tigges S, Roberts DL, Vydareny KH, Schulman DA. Routine Chest radiography in a primary care setting. Radiology 2004;233:575-8.
5. Burill J, Williams CJ, Bain G, Conder G, Hine AL, Misra RR. Tuberculosis: A Radiologic Review. RadioGraphics 2007;27:1255-73.
6. Available from: TB country profile, Cameroon. Surveillance and epidemiology [Last ­accessed on 2011 Mar 26].
7. Andreu J, Caceres J, Pallisa E, Martinez-Rodriguez M. Radiological manifestations of pulmonary tuberculosis. Eur J Radiol 2004;51:139-49.
8. Geijer M, Gothlin JH. Symptoms or no symptoms: Effectiveness of chest radiography. Acad Radiol 1998;5:S333-5.
9. Taylor HG, Stein CM. Clinical effect of admission chest radiographs in Zimbabwe. Lancet 1988;2:440-2.
10. Shah PK, Astin JH, White CS, Patel P, Haramati LB, Pearson GD, et al. Missed non-small cell lung cancer: Radiographic findings of potentially resectable lesions evident only in retrospect. Radiology 2003;226:235-41.
11. Fontana RS, Sanderson DR, Woolner LB, Taylor WF, Miller WE, Muhm JR. Lung cancer screening: The Mayo program. J Occup Med 1986;28:746-50.
12. Marcus PM, Bergstralh EJ, Fagerstrom RM, Williams DE, Fontana R, Taylor WF, et al. Lung cancer mortality in the Mayo Lung Project: Impact of extended follow-up. J Natl Cancer Inst 2000;92:1308-16.
13. Woodring JH, Vandiviere HM, Fried AM, Dillon ML, Williams TD, Melvin IG. Update: The radiographic features of pulmonary tuberculosis. Am J Roentgenol 1986;146:497-506.

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1755-6783.105122


[Figure 1], [Figure 2]


[Table 1], [Table 2]

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