title: A modified method for locating parapharyngeal space neoplasms on magnetic resonance images: implications for differential diagnosis.
abstract: The parapharyngeal space (PPS) is an inverted pyramid-shaped deep space in the head and neck region, and a variety of tumors, such as salivary gland tumors, neurogenic tumors, nasopharyngeal carcinomas with parapharyngeal invasion, and lymphomas, can be found in this space. The differential diagnosis of PPS tumors remains challenging for radiologists. This study aimed to develop and test a modified method for locating PPS tumors on magnetic resonance (MR) images to improve preoperative differential diagnosis. The new protocol divided the PPS into three compartments: a prestyloid compartment, the carotid sheath, and the areas outside the carotid sheath. PPS tumors were located in these compartments according to the displacements of the tensor veli palatini muscle and the styloid process, with or without blood vessel separations and medial pterygoid invasion. This protocol, as well as a more conventional protocol that is based on displacements of the internal carotid artery (ICA), was used to assess MR images captured from a series of 58 PPS tumors. The consequent distributions of PPS tumor locations determined by both methods were compared. Of all 58 tumors, our new method determined that 57 could be assigned to precise PPS compartments. Nearly all (13/14; 93%) tumors that were located in the pre-styloid compartment were salivary gland tumors. All 15 tumors within the carotid sheath were neurogenic tumors. The vast majority (18/20; 90%) of trans-spatial lesions were malignancies. However, according to the ICA-based method, 28 tumors were located in the pre-styloid compartment, and 24 were located in the post-styloid compartment, leaving 6 tumors that were difficult to locate. Lesions located in both the pre-styloid and the post-styloid compartments comprised various types of tumors. Compared with the conventional ICA-based method, our new method can help radiologists to narrow the differential diagnosis of PPS tumors to specific compartments.
authors.affiliation: State Key Laboratory of Oncology in South China; Medical Imaging and Minimally Invasive Interventional Center, Sun Yat-sen University Cancer Center; Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P. R. China. xchuanm@sysucc.org.cn.
authors.forename: Xue-Wen
authors.initials: XW
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Geng
authors.forename: De-Ling
authors.initials: DL
authors.lastname: Wang
authors.forename: Chuan-Miao
authors.initials: CM
authors.lastname: Xie
mesh_terms: D002277:Carcinoma; D003937:Diagnosis, Differential; D006801:Humans; D008223:Lymphoma / Q000175:diagnosis / Q000000981:diagnostic imaging; D009682:Magnetic Resonance Spectroscopy; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging; D009333:Neck / Q000000981:diagnostic imaging*; D009423:Nervous System Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging; D010614:Pharynx / Q000000981:diagnostic imaging*; D011859:Radiography; D012468:Salivary Gland Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging
references.citation: Curr Opin Otolaryngol Head Neck Surg. 2011 Apr;19(2):92-8
references.pmid: 21178619
references.citation: AJR Am J Roentgenol. 2011 Jul;197(1):195-201
references.pmid: 21701030
references.citation: Int J Radiat Oncol Biol Phys. 2009 Nov 1;75(3):742-50
references.pmid: 19251378
references.citation: Head Neck. 1995 Mar-Apr;17(2):124-30
references.pmid: 7558809
references.citation: World Neurosurg. 2010 Jul;74(1):188-94
references.pmid: 21300012
references.citation: Crit Rev Diagn Imaging. 1991;31(3-4):315-56
references.pmid: 2036175
references.citation: J Laryngol Otol. 2002 Mar;116(3):170-5
references.pmid: 11893256
references.citation: Head Neck. 1996 Jan-Feb;18(1):67-77
references.pmid: 8774924
references.citation: Otolaryngol Head Neck Surg. 2005 Apr;132(4):587-91
references.pmid: 15806051
references.citation: Arch Otolaryngol Head Neck Surg. 2007 Jul;133(7):662-7
references.pmid: 17638778
references.citation: Radiology. 1984 Oct;153(1):149-56
references.pmid: 6089262
references.citation: Eur J Radiol. 2012 Jun;81(6):1146-54
references.pmid: 21864999
references.citation: J Otolaryngol. 1990 Apr;19(2):114-21
references.pmid: 2348504
references.citation: Auris Nasus Larynx. 2010 Oct;37(5):621-5
references.pmid: 20185257