Pyriform aperture stenosis refers to narrowing of the pyriform aperture and results from early fusion and hypertrophy of the medial nasal processes.
Pyriform aperture stenosis is a rare cause of airway obstruction, and its prevalence is unknown.
- alobar and semilobar forms of holoprosencephaly
- facial hemangiomas
- pituitary dysfunction
- central megaincisor (in 75% of cases)
HRCT is the imaging modality of choice. It is performed in planes angled along the hard palate with a section thickness of 1-1.5 mm and should include the maxillary spines.
Imaging features of pyriform aperture stenosis include a shelf of tissue extending across the nostrils just inside the nares, inward bowing of the maxillary spines, and narrowing of the pyriform aperture.
No standard measurements exist for the normal pyriform aperture; consequently, the diagnosis of aperture stenosis may be difficult.
MRI / ultrasonography
Associated intracranial anomalies can be excluded in infants with MR imaging or ultrasonography.
Treatment and prognosis
Treatment of mild cases of pyriform aperture stenosis includes administration of decongestants, which allows time for normal nasal growth. Severe cases may require surgical reconstruction with stent placement, sublabial resection of the anteromedial maxilla, or reconstruction of the anterior nasal passages
Possible consideration on axial CT images include
- 1. Lowe LH, Booth TN, Joglar JM et-al. Midface anomalies in children. Radiographics. 20 (4): 907-22. Radiographics (full text) - Pubmed citation
- 2. Haaga JR, Boll D. CT and MRI of the whole body. Mosby. (2009) ISBN:0323053750. Read it at Google Books - Find it at Amazon
- 3. Thomas EM, Gibikote S, Panwar JS et-al. Congenital nasal pyriform aperture stenosis: A rare cause of nasal airway obstruction in a neonate. Indian J Radiol Imaging. 2010;20 (4): 266-8. doi:10.4103/0971-3026.73539 - Free text at pubmed - Pubmed citation
- 4. Belden CJ, Mancuso AA, Schmalfuss IM. CT features of congenital nasal piriform aperture stenosis: initial experience. Radiology. 1999;213 (2): 495-501. doi:10.1148/radiology.213.2.r99oc38495 - Pubmed citation