Ann Thorac Surg 2007;84:2117. doi:10.1016/j.athoracsur.2006.11.009
© 2007 The Society of Thoracic Surgeons
Images in Cardiothoracic Surgery
Demonstration of an Intrathoracic Rib With Computed Tomography and Three-Dimensional Reconstruction
Panayotis Argyriou, MDa,
Dimitrios Pousios, MDb,*,
Dimitrios Tsocanas, MDa,
Constantinos Psathakis, MDa,
Nikolaos Panagiotopoulos, MDb,
Anastasios Piyis, MDb
a Radiology Department, 401 Army General Hospital of Athens, Athens, Greece
b Thoracic Surgery Department, 401 Army General Hospital of Athens, Athens, Greece
* Address correspondence to Dr Pousios, Papanikolaou 7 Str, Patima Halandriou, Athens, 15238, Greece (Email: dpousios{at}yahoo.com).
An intrathoracic rib represents a rare congenital anomaly of the thoracic cage [1]. Usually supernumerary ribs occur unilaterally, more commonly on the right side. In most cases they are asymptomatic; however some patients may have a fibrous diaphragmatic attachment that can cause a restrictive ventilatory defect [2, 3].
A 21-year-old asymptomatic man was admitted to our hospital with a pathologic chest roentgenogram, which showed a broad linear dense band that extended inferiolaterally from the level of the third intercostal space to the level of the posterior portion of the tenth rib. A computed tomographic scan with a Lightspeed Plus Helical 4-slice CT scanner (General Electric, New York, NY) was performed and confirmed the posterior, extrapleural location of the lesion (see Fig 1,
arrows). The structure was articulated with the fourth thoracic vertebral body. A small fibrous diaphragmatic attachment was visualized suggesting the possibility of an intrathoracic rib. The bone window demonstrated the bony cortex of the lesion. A three-dimensional reconstruction in an Advantage Workstation 4.0 (General Electric) with a 5-mm slice thickness was performed, and the radiographic feature was unique (Fig 2).
Approximately 40 cases were found in a review of the literature [2], but only four were demonstrated with computed tomography [1, 2, 4]. We believe that only one report included a three-dimensional demonstration of an intrathoracic rib [2].
According to one hypothesis, the anomaly is a result of incomplete fusion between component halves of adjacent sclerotomes during embryogenesis [1]. Computed tomography has many advantages in demonstrating this specific thoracic congenital anomaly. It can depict the cortical bone, the extrapleural location, and the usual extension from rib or vertebra and also show the potential fibrous diaphragmatic attachment [1].
The three-dimensional reconstruction demonstrates with high accuracy the origin and extent of an intrathoracic rib. Therefore it seems to be the modality of choice for localization [2].
The significance of recognizing an intrathoracic rib lies in the fact that it is an innocuous thoracic anomaly and should not be mistaken for either a parenchymal or pleural lesion or even an artifact [1].
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References
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- Trigaux JP, Sibille Y, Van Beers B. Intrathoracic rib: CT features J Comput Ass Tomogr 1990;14:133-135.
- Laufer L, Schulman H, Hertzanu Y. Intrathoracic rib demonstrated by helical CT with three-dimensional reconstruction Eur Radiol 1999;9:60-61.[Medline]
- Kelleher J, O’Connel DJ, MacMahon H. Intrathoracic rib radiographic features of two cases Br J Radiol 1979;52:181-183.[Abstract/Free Full Text]
- Peterson M, Plunkett M. Demonstration of an intrathoracic rib AJR Am J Roentgenol 1993;160:895.[Medline]
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