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Radiological characteristics of pulmonary hydatid disease in children
European Journal of Radiology 45 (2003) 123 /128 www.elsevier.com/locate/ejrad
Review
Radiological characteristics of pulmonary hydatid disease in children Less common radiological appearances C. Zuhal Erdem *, L. Oktay Erdem Department of Radiology, School of Medicine, Zonguldak Karaelmas University, 67600 Kozlu/Zonguldak, Turkey Received 3 December 2001; received in revised form 6 February 2002; accepted 8 February 2002
Abstract Objective: To evaluate the chest roentgenogram and CT characteristics of pulmonary hydatid disease (PHD). Material and methods: Forty-seven (27 male and 20 female, aged between 3 and 11 years) consecutive pediatric patients with surgically proven pulmonary hydatid cysts were enrolled for the study. Posteroanterior and lateral chest roentgenograms, CT of the chest, and laboratory findings (latex agglutination, Casoni skin test, and eosinophil count) were obtained from all of the patients. The radiological features (localization, internal architecture, number, diameter) were determined. Results: On CT examination, a total of 79 cysts were determined. On chest roentgenogram, 57 of 79 cysts were detected in all patients. Single cysts were seen in 33 patients, while multiple cysts were seen in 14. Median CT density of the cysts was 21 Hounsfield units (HU) (0 /80). There were six giant cysts ( /10 cm of cyst diameter). The crescent sign, water lily sign, and air /fluid level were seen in two, five and eight of the cysts, respectively. Apart from the classically described features of pulmonary hydatid cysts of the lung, a crescent-shaped rim of air at the lower end of the cyst (inverse crescent sign) was detected in three cysts. All of the liquid content of the cyst was expelled to the bronchial system (dry cyst sign) was observed in seven cysts. There were two infected cysts. Heavily calcified curvilinear cyst wall was present in one cyst. Pericystic reaction in the lung tissue was observed in five patients. Other features included pleural effusion (n /2), mediastinal shift (n /6) and atelectasis (n /7). Conclusions: Chest roentgenogram is helpful for diagnosis of intact cysts but, it is impossible to define entire morphology of the complicated cysts. CT imaging recognize certain details of the lesions and discover others that are not visible by conventional radiography. In conclusion, CT examination should be done to elucidate cystic nature of the lung mass and for accurate localization in the preoperative period. In addition, inverse crescent sign should be recognized as feature of pulmonary hydatid cysts on CT. # 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Hydatid disease; Lung; Radiology
1. Introduction Human hydatid disease is still endemic and an important health problem in Turkey. The incidence of the disease is said to be 2/100 000 [1,2]. The lung is the most common site affected in children, while it is the liver in adults [3,4]. The aim of this study is to present the chest roentgenogram and CT of the chest characteristics of pulmonary hydatid disease (PHD) and to
* Corresponding author. Tel.: /90-372-261-0619; fax: /90-372261-0155 E-mail address: [email protected] (C.Z. Erdem).
discuss the less common radiological presentations of this endemic disorder in Turkey.
2. Patients and methods We presented 47 pediatric cases (27 male and 20 female, aged between 3 and 11 years) who were operated on and diagnosed with PHD histopathologically. The various symptoms experienced by the patients including fever (n /21), cough (n /35), hemoptysis (n /2) chest pain (n /17), and anorexia (n /5). Anaphylactic reaction was not observed in patients with complicated cysts.
0720-048X/02/$ - see front matter # 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 7 2 0 - 0 4 8 X ( 0 2 ) 0 0 0 5 4 - 2
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C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
The latex agglutination test was positive in 29 of 47 patients (61%). Casoni skin test was also positive in 34 of 47 patients (72%). Eosinophilia was present in 16 of 47 patients (34%).
Table 1 The localization of pulmonary hydatid cysts on CT scan Localization
Number of cysts
%
Right lower lobe Right middle lobe Left lower lobe Right upper lobe Left upper lobe
28 20 15 9 7
36 25 19 11 9
Preoperative radiological studies included posteroanterior and lateral chest roentgenogram, and CT of the chest in all patients. All patients were subjected to surgery. The specimens were sent for pathological examination.
3. Results
Fig. 1. Chest roentgenogram shows multiple irregular opacities in both of the lungs.
Fig. 2. The cyst containing air /fluid level is located in the lower lobe of the left lung.
Single cyst were seen in 33 (70%) patients and multiple cysts in 14 (30%). On CT examination a total of 79 cysts were localized cysts were unilaterally in 36 patients and bilaterally in 11. There were six giant cysts (/10 cm of cyst diameter). On chest roentgenogram, 57 cysts were determined. Twelve cysts were not able to be seen because of overlapping each other or location behind the heart. The cysts appear as round, homogeneous, well defined (n /45) and irregular (n /12) opacities (Fig. 1). In five of the thirteen perforated cysts, the water-lily sign (endocyst membrane floating on top of remaining fluid consequent on collapse of endocyst and partial evacuation of fluid) were seen and air /fluid level (Fig. 2) were seen in eight of the 13 perforated cysts. Pericystic reaction in the lung tissue was demonstrable in five patients. Other features included pleural effusion (n / 2), mediastinal shift (n /6) and atelectasis (n /7). Localizations of the cysts on CT scanning were right lower lobe in 28, left lower lobe in 15, right middle lobe in 20, left upper lobe in seven, and right upper lobe in nine cysts (Table 1). The size of the cysts varied from 1 to 15 cm (mean9/S.D., 3.429/1.7). Various shapes encountered were round (n /52), irregular (n /18), oval (n /5), and pear-shaped (in /4). Seventy-five cysts were uniloculate (Fig. 3), whereas internal septa with multiple loculations were seen in four cysts. Twenty five cysts (32%) were ruptured, while 54 cysts (68%) were not. The ruptured cysts appearances included air /fluid level, dry cyst sign, water lily sign, inverse crescent sign, and crescent sign (Table 2). The crescent sign (Fig. 4), water lily sign (Fig. 5), and air /fluid level were seen in two, five, and eight of the cysts, respectively. Inverse crescent sign (a crescent-shaped rim of air at the lower end of the cyst) (Fig. 6) was seen in three cysts and dry cyst sign (all of the liquid content of the cyst is expelled
C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
125
Fig. 3. A large uniloculate cyst.
to the bronchial system) (Fig. 7) was observed in seven cysts. Median CT density of all of the cysts was 21 Hounsfield units (HU; 0 /80 HU). The median density was 47 HU in ruptured cysts (36 /80 HU), and 18 HU in unruptured ones (6 /59 HU). There were two infected cysts and the median density was found to be 77 HU (48 and 106 HU). Heavily calcified curvilinear cyst wall was present in one cyst. Pericystic reaction in the lung tissue was demonstrable in five patients (Fig. 7). Other features included pleural effusion (n /2), mediastinal shift (n /6) and atelectasis (n /7). The cyst wall was smooth in 73 cysts and irregular in six cysts. The wall thickness ranged from 1 to 17 mm.
4. Discussion and conclusion Radiological signs are clear and precise unlike the clinical presentation. On chest roentgenogram, the typical image of the simple cyst (intact, closed) is that of a homogenous opacity, round with definite edges, situated in the pulmonary field [2,3,5]. Differential diagnosis includes benign tumors, inflammatory masses, metastasis, solid or fluid-filled cysts, and carcinomas [6 / 8]. In anteroposterior projection it resembles a cannonball; in lateral projection, it is longer, similar to a rugby ball [5]. Chest roentgenogram is routinely employed for diagnosis of the disease in developing countries. Although chest roentgenogram is almost always diagnostic, hydatid lung disease may present itself in a variety of radiological forms, especially it is impossible to define entire morphology of the complicated cysts.
In this study, thirteen ruptured cysts were determined on chest roentgenogram whereas 25 ruptured cysts were determined on CT examination. This is due to the fact that; internal architecture characteristics such as; crescent sign, inverse crescent sign, and dry cyst sign can not determined on chest roentgenograms. On CT examination, in five cysts, a cresent-like rim of air was observed at the lower end of the cyst (Fig. 6), with an appearance that was morphologically opposite of the classic cresent sign. We referred the same terminology by Parvaiz et al. [9] who termed it as inverse crescent sign which results from air dissection induced separation of the membranes from the posterior aspect of the cyst without any anterior extension. The cyst may rupture into bronchus and expel a part or less commonly whole of its liquid content into the bronchial system. On CT examination, in seven of our cysts were totally air filled (Fig. 7). It is termed as dry cyst sign [10]. It is very important in differential diagnosis from cavitary lesions of the lung, such as, aspergillomas, cavitary tuberculosis, and malignant neoplasms [11]. Table 2 CT appearances of ruptured pulmonary hydatid cysts Lesion type
Number of cysts
Air-fluid level Dry cyst sign Water lily sign Inverse crescent sign Crescent sign
8 7 5 3 2
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C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
Fig. 4. Crescent sign.
Fig. 5. The cyst with water lily appearance localized peripherally and atelectasis in the pericystic lung tissue.
CT scanning may well elucidate the cystic nature of the lung mass and helps preoperative evaluation of the cysts. CT is helpful for the demonstration of the water density in the intact cysts [12]. PHD can be located elsewhere in the lung but the right lobe and lower lobe is the most frequently affected area [2,13,14]. In our study the right lung was also found to be affected in 72% of patients and the left in 28%. And also, right lower lobe was found to be affected in 36% and left lower lobe in 19% of patients.
It has been reported in the literature that, PHD is mostly seen as solitary (75 /80%) and less commonly as multiple (20 /25%) lesions [10,14]. In our study, 70% patients had solitary cyst and 30% had multiple cysts similar to the literature findings. CT imaging also can distinguish pleural from pulmonary or chest wall pathology accurately [9,12]. CT is often the best technique to evaluate complex cases that have disease in more than one of these thoracic compartments. CT also detects additional cysts
C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
that cannot be seen in chest roentgenograms [15]. In our study, 57 cysts were founded on chest roentgenogram and 79 cysts on CT examination. The most frequent complication of pulmonary hydatid cyst is perforation because of degeneration in the wall of the cyst [16]. The most common serious complication of rupture is bacterial infection [16,17]. CT best demonstrates cyst infection, cyst wall calcification and certain details of the cyst [18,19]. In this series perforated cysts were seen in 25 patients and infected cysts were in two making radiological confirmation difficult. Both rupture and infection can change the appearance of the cyst on routine roentgenograms. In
127
such circumstances CT helps to reach the final diagnosis [19]. Although there are some arguments about the necessity of CT in PHD, we believe that tomography is necessary, especially for complex cases with multiple cysts in different thoracic compartments, or with perforated or infected cysts. CT provides further information about the state of the affected lobes, the size of the hydatid cyst and its relation to the lung parenchyma. In conclusion, CT examination should be done to elucidate cystic nature of the lung mass and for accurate localization in the preoperative period. In addition,
Fig. 6. Inverse crescent sign.
Fig. 7. CT scan showing dry cyst sign and pericystic reaction.
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inverse crescent sign should be recognized as feature of pulmonary hydatid cysts on CT.
Acknowledgements There is no financial support received, except regular hospital investigations.
References [1] Dogan R, Yu¨ksel M, .C ¸ etin G, Su¨zer K, Alp M, Kaya S. Surgical treatment of hydatid cysts of the lung: Report on 1055 patients. Thorax 1989;44:192 /9. [2] Aytac¸ A, Yurdakul Y, Ikizler C, Olga R, Saylam A. Pulmonary hydatid disease: Report of 100 patients. Ann Thorac Surg 1997;23:145 /51. ¨ zmen M, Besim A. Spectrum [3] Halilog˘lu M, Saatc¸i I, Akhan O, .O of imaging findings in pediatric hydatid disease. Am J Roentgenol 1997;169:127 /31. [4] Solak H, Yeniterzi M, Yu¨ksek T. The hydatid cysts of the lung in children and results of surgical treatment. Thorac Cardiovasc Surg 1990;38:45 /7. [5] Larbaoui D. Le kyste hydatique du poumon. Rev Pneumol Clin 1989;45:49. [6] Sakouk FA, Fahl MH, Rizk GK. Computed tomography of pulmonary hydatid disease. J Comput Asist Tomogr 1986;10:226 /32. [7] Kegel RFC, Fateni A. Ruptured pulmonary hydatid cyst. Radiology 1961;76:60 /4. [8] Aggrawal S, Kumar A, Mukhopaday S. A new radiological sign of ruptured pulmonary hydatid cyst. Am J Radiol 1989;152:431 /2.
[9] Parvaiz AK, Koul AN, Wahid A, Mir FA. CT in pulmonary hydatid disease. Chest 2000;118:1645 /7. [10] Burgener AF, Karmano M. Pulmonary nodules and mass lesions. In: Burgener AF, Karmano M, editors. Differential diagnosis in conventional radiology, 2nd ed.. New York: Thieme, 1991:472. [11] Roberts JM, Citron KM, Strickland B. Intrathroracic aspergilloma: role of CT in diagnosis and treatment. Radiology 1987;165:123 /8. [12] Godwin JD. Pleural disease. In: Putman CE, Ravin CE, editors. Textbook of diagnostic imaging, 2nd ed.. Philadelphia: Saunders, 1994:450. [13] Beltran de Heredia JM. Hidatidosis pulmonar. In: Balibrea Cantero JL, editor. Tradatado de Cirurgia, vol. 1. Barcelona: Ediciones Toray S.A, 1988:1210 /25. [14] Lamy AL, Cameron BH, LeBlanc JG. Giant hydatid lung cysts in the Canadian Northwest: outcome of conservative treatment in three children. J Pediatr Surg 1993;28:1140 /3. [15] .C ¸ elik M, S¸enol C, Keles¸ M, Halezerog˘lu S¸, Urek S, Haciibrahimog˘lu G, Ersev AA, Arman B. Surgical treatment of pulmonary hydatid disease in children: Report of 122 cases. J Pediatr Surg 2000;35:1710 /3. [16] Bonakdarpour A. Echinococcus disease. Report of 112 cases from Iran and a review of 611 cases from the United States. Am J Roentegenol 1967;99:660 /7. [17] Freixinet JL, Mestres E, Cugat E, Mateu M. Hepaticothoracic transdiafragmatic echinococosis. Ann Throrac Surg 1988;45:426 / 9. [18] Ramos L, Hernandez-Mora M, Illanas M, Llorente MT, Marcos R. Radiological characteristics of perforated pulmonary hydatid cysts. Radiology 1975;116:539 /42. [19] Tor M, Ozvaran K, Ersoy Y, .S¸enol T, Altuntas¸ N, Kilic¸og˘lu G, C ¸ elik L. Pitfalls in the diagnosis of complicated pulmonary hydatid disease. Resp Med 2001;95:237 /9.
Review
Radiological characteristics of pulmonary hydatid disease in children Less common radiological appearances C. Zuhal Erdem *, L. Oktay Erdem Department of Radiology, School of Medicine, Zonguldak Karaelmas University, 67600 Kozlu/Zonguldak, Turkey Received 3 December 2001; received in revised form 6 February 2002; accepted 8 February 2002
Abstract Objective: To evaluate the chest roentgenogram and CT characteristics of pulmonary hydatid disease (PHD). Material and methods: Forty-seven (27 male and 20 female, aged between 3 and 11 years) consecutive pediatric patients with surgically proven pulmonary hydatid cysts were enrolled for the study. Posteroanterior and lateral chest roentgenograms, CT of the chest, and laboratory findings (latex agglutination, Casoni skin test, and eosinophil count) were obtained from all of the patients. The radiological features (localization, internal architecture, number, diameter) were determined. Results: On CT examination, a total of 79 cysts were determined. On chest roentgenogram, 57 of 79 cysts were detected in all patients. Single cysts were seen in 33 patients, while multiple cysts were seen in 14. Median CT density of the cysts was 21 Hounsfield units (HU) (0 /80). There were six giant cysts ( /10 cm of cyst diameter). The crescent sign, water lily sign, and air /fluid level were seen in two, five and eight of the cysts, respectively. Apart from the classically described features of pulmonary hydatid cysts of the lung, a crescent-shaped rim of air at the lower end of the cyst (inverse crescent sign) was detected in three cysts. All of the liquid content of the cyst was expelled to the bronchial system (dry cyst sign) was observed in seven cysts. There were two infected cysts. Heavily calcified curvilinear cyst wall was present in one cyst. Pericystic reaction in the lung tissue was observed in five patients. Other features included pleural effusion (n /2), mediastinal shift (n /6) and atelectasis (n /7). Conclusions: Chest roentgenogram is helpful for diagnosis of intact cysts but, it is impossible to define entire morphology of the complicated cysts. CT imaging recognize certain details of the lesions and discover others that are not visible by conventional radiography. In conclusion, CT examination should be done to elucidate cystic nature of the lung mass and for accurate localization in the preoperative period. In addition, inverse crescent sign should be recognized as feature of pulmonary hydatid cysts on CT. # 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Hydatid disease; Lung; Radiology
1. Introduction Human hydatid disease is still endemic and an important health problem in Turkey. The incidence of the disease is said to be 2/100 000 [1,2]. The lung is the most common site affected in children, while it is the liver in adults [3,4]. The aim of this study is to present the chest roentgenogram and CT of the chest characteristics of pulmonary hydatid disease (PHD) and to
* Corresponding author. Tel.: /90-372-261-0619; fax: /90-372261-0155 E-mail address: [email protected] (C.Z. Erdem).
discuss the less common radiological presentations of this endemic disorder in Turkey.
2. Patients and methods We presented 47 pediatric cases (27 male and 20 female, aged between 3 and 11 years) who were operated on and diagnosed with PHD histopathologically. The various symptoms experienced by the patients including fever (n /21), cough (n /35), hemoptysis (n /2) chest pain (n /17), and anorexia (n /5). Anaphylactic reaction was not observed in patients with complicated cysts.
0720-048X/02/$ - see front matter # 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 7 2 0 - 0 4 8 X ( 0 2 ) 0 0 0 5 4 - 2
124
C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
The latex agglutination test was positive in 29 of 47 patients (61%). Casoni skin test was also positive in 34 of 47 patients (72%). Eosinophilia was present in 16 of 47 patients (34%).
Table 1 The localization of pulmonary hydatid cysts on CT scan Localization
Number of cysts
%
Right lower lobe Right middle lobe Left lower lobe Right upper lobe Left upper lobe
28 20 15 9 7
36 25 19 11 9
Preoperative radiological studies included posteroanterior and lateral chest roentgenogram, and CT of the chest in all patients. All patients were subjected to surgery. The specimens were sent for pathological examination.
3. Results
Fig. 1. Chest roentgenogram shows multiple irregular opacities in both of the lungs.
Fig. 2. The cyst containing air /fluid level is located in the lower lobe of the left lung.
Single cyst were seen in 33 (70%) patients and multiple cysts in 14 (30%). On CT examination a total of 79 cysts were localized cysts were unilaterally in 36 patients and bilaterally in 11. There were six giant cysts (/10 cm of cyst diameter). On chest roentgenogram, 57 cysts were determined. Twelve cysts were not able to be seen because of overlapping each other or location behind the heart. The cysts appear as round, homogeneous, well defined (n /45) and irregular (n /12) opacities (Fig. 1). In five of the thirteen perforated cysts, the water-lily sign (endocyst membrane floating on top of remaining fluid consequent on collapse of endocyst and partial evacuation of fluid) were seen and air /fluid level (Fig. 2) were seen in eight of the 13 perforated cysts. Pericystic reaction in the lung tissue was demonstrable in five patients. Other features included pleural effusion (n / 2), mediastinal shift (n /6) and atelectasis (n /7). Localizations of the cysts on CT scanning were right lower lobe in 28, left lower lobe in 15, right middle lobe in 20, left upper lobe in seven, and right upper lobe in nine cysts (Table 1). The size of the cysts varied from 1 to 15 cm (mean9/S.D., 3.429/1.7). Various shapes encountered were round (n /52), irregular (n /18), oval (n /5), and pear-shaped (in /4). Seventy-five cysts were uniloculate (Fig. 3), whereas internal septa with multiple loculations were seen in four cysts. Twenty five cysts (32%) were ruptured, while 54 cysts (68%) were not. The ruptured cysts appearances included air /fluid level, dry cyst sign, water lily sign, inverse crescent sign, and crescent sign (Table 2). The crescent sign (Fig. 4), water lily sign (Fig. 5), and air /fluid level were seen in two, five, and eight of the cysts, respectively. Inverse crescent sign (a crescent-shaped rim of air at the lower end of the cyst) (Fig. 6) was seen in three cysts and dry cyst sign (all of the liquid content of the cyst is expelled
C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
125
Fig. 3. A large uniloculate cyst.
to the bronchial system) (Fig. 7) was observed in seven cysts. Median CT density of all of the cysts was 21 Hounsfield units (HU; 0 /80 HU). The median density was 47 HU in ruptured cysts (36 /80 HU), and 18 HU in unruptured ones (6 /59 HU). There were two infected cysts and the median density was found to be 77 HU (48 and 106 HU). Heavily calcified curvilinear cyst wall was present in one cyst. Pericystic reaction in the lung tissue was demonstrable in five patients (Fig. 7). Other features included pleural effusion (n /2), mediastinal shift (n /6) and atelectasis (n /7). The cyst wall was smooth in 73 cysts and irregular in six cysts. The wall thickness ranged from 1 to 17 mm.
4. Discussion and conclusion Radiological signs are clear and precise unlike the clinical presentation. On chest roentgenogram, the typical image of the simple cyst (intact, closed) is that of a homogenous opacity, round with definite edges, situated in the pulmonary field [2,3,5]. Differential diagnosis includes benign tumors, inflammatory masses, metastasis, solid or fluid-filled cysts, and carcinomas [6 / 8]. In anteroposterior projection it resembles a cannonball; in lateral projection, it is longer, similar to a rugby ball [5]. Chest roentgenogram is routinely employed for diagnosis of the disease in developing countries. Although chest roentgenogram is almost always diagnostic, hydatid lung disease may present itself in a variety of radiological forms, especially it is impossible to define entire morphology of the complicated cysts.
In this study, thirteen ruptured cysts were determined on chest roentgenogram whereas 25 ruptured cysts were determined on CT examination. This is due to the fact that; internal architecture characteristics such as; crescent sign, inverse crescent sign, and dry cyst sign can not determined on chest roentgenograms. On CT examination, in five cysts, a cresent-like rim of air was observed at the lower end of the cyst (Fig. 6), with an appearance that was morphologically opposite of the classic cresent sign. We referred the same terminology by Parvaiz et al. [9] who termed it as inverse crescent sign which results from air dissection induced separation of the membranes from the posterior aspect of the cyst without any anterior extension. The cyst may rupture into bronchus and expel a part or less commonly whole of its liquid content into the bronchial system. On CT examination, in seven of our cysts were totally air filled (Fig. 7). It is termed as dry cyst sign [10]. It is very important in differential diagnosis from cavitary lesions of the lung, such as, aspergillomas, cavitary tuberculosis, and malignant neoplasms [11]. Table 2 CT appearances of ruptured pulmonary hydatid cysts Lesion type
Number of cysts
Air-fluid level Dry cyst sign Water lily sign Inverse crescent sign Crescent sign
8 7 5 3 2
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C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
Fig. 4. Crescent sign.
Fig. 5. The cyst with water lily appearance localized peripherally and atelectasis in the pericystic lung tissue.
CT scanning may well elucidate the cystic nature of the lung mass and helps preoperative evaluation of the cysts. CT is helpful for the demonstration of the water density in the intact cysts [12]. PHD can be located elsewhere in the lung but the right lobe and lower lobe is the most frequently affected area [2,13,14]. In our study the right lung was also found to be affected in 72% of patients and the left in 28%. And also, right lower lobe was found to be affected in 36% and left lower lobe in 19% of patients.
It has been reported in the literature that, PHD is mostly seen as solitary (75 /80%) and less commonly as multiple (20 /25%) lesions [10,14]. In our study, 70% patients had solitary cyst and 30% had multiple cysts similar to the literature findings. CT imaging also can distinguish pleural from pulmonary or chest wall pathology accurately [9,12]. CT is often the best technique to evaluate complex cases that have disease in more than one of these thoracic compartments. CT also detects additional cysts
C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
that cannot be seen in chest roentgenograms [15]. In our study, 57 cysts were founded on chest roentgenogram and 79 cysts on CT examination. The most frequent complication of pulmonary hydatid cyst is perforation because of degeneration in the wall of the cyst [16]. The most common serious complication of rupture is bacterial infection [16,17]. CT best demonstrates cyst infection, cyst wall calcification and certain details of the cyst [18,19]. In this series perforated cysts were seen in 25 patients and infected cysts were in two making radiological confirmation difficult. Both rupture and infection can change the appearance of the cyst on routine roentgenograms. In
127
such circumstances CT helps to reach the final diagnosis [19]. Although there are some arguments about the necessity of CT in PHD, we believe that tomography is necessary, especially for complex cases with multiple cysts in different thoracic compartments, or with perforated or infected cysts. CT provides further information about the state of the affected lobes, the size of the hydatid cyst and its relation to the lung parenchyma. In conclusion, CT examination should be done to elucidate cystic nature of the lung mass and for accurate localization in the preoperative period. In addition,
Fig. 6. Inverse crescent sign.
Fig. 7. CT scan showing dry cyst sign and pericystic reaction.
128
C.Z. Erdem, L.O. Erdem / European Journal of Radiology 45 (2003) 123 /128
inverse crescent sign should be recognized as feature of pulmonary hydatid cysts on CT.
Acknowledgements There is no financial support received, except regular hospital investigations.
References [1] Dogan R, Yu¨ksel M, .C ¸ etin G, Su¨zer K, Alp M, Kaya S. Surgical treatment of hydatid cysts of the lung: Report on 1055 patients. Thorax 1989;44:192 /9. [2] Aytac¸ A, Yurdakul Y, Ikizler C, Olga R, Saylam A. Pulmonary hydatid disease: Report of 100 patients. Ann Thorac Surg 1997;23:145 /51. ¨ zmen M, Besim A. Spectrum [3] Halilog˘lu M, Saatc¸i I, Akhan O, .O of imaging findings in pediatric hydatid disease. Am J Roentgenol 1997;169:127 /31. [4] Solak H, Yeniterzi M, Yu¨ksek T. The hydatid cysts of the lung in children and results of surgical treatment. Thorac Cardiovasc Surg 1990;38:45 /7. [5] Larbaoui D. Le kyste hydatique du poumon. Rev Pneumol Clin 1989;45:49. [6] Sakouk FA, Fahl MH, Rizk GK. Computed tomography of pulmonary hydatid disease. J Comput Asist Tomogr 1986;10:226 /32. [7] Kegel RFC, Fateni A. Ruptured pulmonary hydatid cyst. Radiology 1961;76:60 /4. [8] Aggrawal S, Kumar A, Mukhopaday S. A new radiological sign of ruptured pulmonary hydatid cyst. Am J Radiol 1989;152:431 /2.
[9] Parvaiz AK, Koul AN, Wahid A, Mir FA. CT in pulmonary hydatid disease. Chest 2000;118:1645 /7. [10] Burgener AF, Karmano M. Pulmonary nodules and mass lesions. In: Burgener AF, Karmano M, editors. Differential diagnosis in conventional radiology, 2nd ed.. New York: Thieme, 1991:472. [11] Roberts JM, Citron KM, Strickland B. Intrathroracic aspergilloma: role of CT in diagnosis and treatment. Radiology 1987;165:123 /8. [12] Godwin JD. Pleural disease. In: Putman CE, Ravin CE, editors. Textbook of diagnostic imaging, 2nd ed.. Philadelphia: Saunders, 1994:450. [13] Beltran de Heredia JM. Hidatidosis pulmonar. In: Balibrea Cantero JL, editor. Tradatado de Cirurgia, vol. 1. Barcelona: Ediciones Toray S.A, 1988:1210 /25. [14] Lamy AL, Cameron BH, LeBlanc JG. Giant hydatid lung cysts in the Canadian Northwest: outcome of conservative treatment in three children. J Pediatr Surg 1993;28:1140 /3. [15] .C ¸ elik M, S¸enol C, Keles¸ M, Halezerog˘lu S¸, Urek S, Haciibrahimog˘lu G, Ersev AA, Arman B. Surgical treatment of pulmonary hydatid disease in children: Report of 122 cases. J Pediatr Surg 2000;35:1710 /3. [16] Bonakdarpour A. Echinococcus disease. Report of 112 cases from Iran and a review of 611 cases from the United States. Am J Roentegenol 1967;99:660 /7. [17] Freixinet JL, Mestres E, Cugat E, Mateu M. Hepaticothoracic transdiafragmatic echinococosis. Ann Throrac Surg 1988;45:426 / 9. [18] Ramos L, Hernandez-Mora M, Illanas M, Llorente MT, Marcos R. Radiological characteristics of perforated pulmonary hydatid cysts. Radiology 1975;116:539 /42. [19] Tor M, Ozvaran K, Ersoy Y, .S¸enol T, Altuntas¸ N, Kilic¸og˘lu G, C ¸ elik L. Pitfalls in the diagnosis of complicated pulmonary hydatid disease. Resp Med 2001;95:237 /9.