DOI: 10.1148/rg.235025045
(Radiographics. 2003;23:1201-1213.)
© RSNA, 2003
Dynamic Maneuvers in Local Staging of Head and Neck Malignancies with Current Imaging Techniques: Principles and Clinical Applications1
Philippe Henrot, MD,
Alain Blum, MD,
Bruno Toussaint, MD,
Philippe Troufleau, MD,
Joseph Stines, MD and
Jacques Roland, MD
1 From the Department of Radiology, Centre Alexis Vautrin, Ave de Bourgogne, 54511 Vandoeuvre-lès-Nancy, France (P.H., P.T., J.S.); and the Departments of Radiology Guilloz (A.B., J.R.) and Head and Neck Surgery (B.T.), Hôpital Central University of Nancy 1, France. Presented as an education exhibit at the 2001 RSNA scientific assembly. Received March 4, 2002; revision requested April 8; final revision received February 10, 2003; accepted February 13. Address correspondence to P.H. (e-mail: p.henrot@nancy.fnclcc.fr).
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Abstract
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Imaging has been widely demonstrated to be important in local staging of head and neck malignancies as a complement to clinical examination, including endoscopy. Recent developments in multidetector row computed tomography (CT) provide better anatomic resolution within a shorter acquisition time and wider anatomic coverage. However, in many cases lesions still remain undefined. In such cases, performance of dynamic maneuvers could provide useful information about the local extent of a tumor. The usefulness of dynamic maneuvers has increased with the improvement in temporal and spatial resolution that resulted from the most recent techniques of multidetector row CT. The puffed cheek technique and the modified Valsalva maneuver allow evaluation of a lesion that was poorly demonstrated owing to apposition of mucosal surfaces. In some cases, phonation improves demonstration of small lesions of the vocal cords and allows more precise anatomic localization. The open mouth technique allows demonstration of a lesion that was previously overlooked due to dental amalgam artifacts.
© RSNA, 2003
Index Terms: Head and neck neoplasms, staging, 20.37 • Larynx, neoplasms, 271.37 • Mouth, neoplasms, 262.37 • Pharynx, neoplasms, 26.37, 272.37
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LEARNING OBJECTIVES
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After reading this article and taking the test, the reader will be able to:
- List the indications for the various dynamic maneuvers.
- Describe the techniques of the various dynamic maneuvers.
- Discuss the effects of each dynamic maneuver on the anatomy of the head and neck.
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Introduction
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Local staging of head and neck malignancies is performed both clinically including endoscopy and by using imaging techniques. Visual and endoscopic examination may depict a mass, an ulceration, or both. In certain cases, abnormal coloration of the mucosa is the sole tumoral manifestation. In other cases, lack of mucosal pliability or fixation of a hemilarynx may be observed. Manual inspection reveals only abnormalities of the oral cavity and oropharynx. Clinical examination often understages the deep spread of tumors, and the submucosal extent may be overlooked (1–4). Imaging provides additional staging information to determine more precisely the exact local extent of the tumor. Moreover, it helps determine the nodal staging in the same examination time. Anatomic accuracy of the local staging can contribute to selection of the most effective therapeutic strategy in respect to respiratory and swallowing functions. It also helps preserve the voice without increasing the risk of local recurrence.
Computed tomography (CT) is the modality of choice for head and neck malignancies. Its spatial and temporal resolution allows good delineation of small moving structures like laryngeal structures. These properties have been boosted with the introduction of multidetector row CT (5–7). The decrease of gantry rotation speed to under 1 second (currently 0.5–0.8 second per rotation) and the ability to obtain four to 16 sections per revolution have improved temporal resolution. A large coverage volume from the base of the skull to the root of the neck is acquired within 20 seconds. Motion artifacts occurring during respiration are considerably reduced, and the acquisition can currently be performed during quiet respiration. The possibility of obtaining four to 16 0.75–1.25-mm-thick sections simultaneously has increased spatial resolution. Anatomic depiction of small structures like the vocal cords becomes easier, and multiplanar reformation yields a quality of exploration similar to that of native axial sections. Three-dimensional reformation has an added didactic value for documenting the lesions. Injection of contrast media can be standardized to achieve reproducible enhancement of the lesions. A multidetector row CT protocol for work-up of patients with head and neck malignancies is suggested in the Table.
However, despite its improved capabilities, CT does not always accurately depict the tumor nor demonstrate its margins. Apposed anatomic structures are sometimes difficult to distinguish from each other, and the exact outline of the tumor may still be undefined. In the case of a small tumor, apposition could almost hide the lesion. Moreover, during apnea and quiet respiration, the true vocal cords and the laryngeal ventricles are poorly visualized; consequently, small lesions could be misdiagnosed. In addition, examination of the oral cavity and oropharynx is often inconclusive due to dental amalgam artifacts.
In the aforementioned situations, additional scanning with dedicated dynamic maneuvers could improve the staging. In this article, the use of dynamic maneuvers in local staging of head and neck malignancies with current imaging techniques is presented. Specific maneuvers discussed are the puffed cheek technique, the modified Valsalva maneuver, phonation, and the open mouth technique.
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Puffed Cheek Technique
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Indications
The puffed cheek technique is indicated following a previous quiet respiration examination when the apposition of the buccal mucosal surface and the gingival mucosal surface hinders location and demonstration of the extent of a tumor of the oral cavity. It may also be useful when the mucosal surfaces of the tongue and the gingiva are apposed.
Method
This technique was recently described by Weissman and Carrau (8). Puffed cheek CT is performed by having the patient blow uniformly through pursed lips. This technique could be optimized by having the patient move the tongue away from the hard palate and the teeth.
Technical Parameters
The scanning range is programmed from the hard palate to the inferior edge of the mandible. A 1-mm section thickness provides optimal spatial resolution. The pitch and table speed are selected so as to contain the acquisition time within 10 seconds. A suggested imaging protocol is summarized in the Table.
Results
Structures that are normally apposed, like the cheeks, gingiva, lips, and buccal vestibule, are well depicted by using this technique. The buccinator muscle, pterygomandibular raphe, and retromolar trigone are well delineated. The location of a tumor on the buccal mucosa or gingival mucosa is clearly depicted (Fig 1). In the case of a tumor of the retromolar trigone, cheek involvement can be confirmed or precluded (Fig 2).
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Figure 1a. Squamous cell carcinoma of the right buccal vestibule. (a) Axial CT scan shows a tumor (arrow) but does not clearly demonstrate which wall is involved. (b) Axial CT scan obtained with the puffed cheek technique shows involvement of both the buccal mucosa (white arrow) and the gingival mucosa (black arrows). (c) Coronal reformatted image obtained with the puffed cheek technique shows involvement of the right cheek (white arrow) and the gingiva (black arrow). * = buccinator muscle.
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Figure 1b. Squamous cell carcinoma of the right buccal vestibule. (a) Axial CT scan shows a tumor (arrow) but does not clearly demonstrate which wall is involved. (b) Axial CT scan obtained with the puffed cheek technique shows involvement of both the buccal mucosa (white arrow) and the gingival mucosa (black arrows). (c) Coronal reformatted image obtained with the puffed cheek technique shows involvement of the right cheek (white arrow) and the gingiva (black arrow). * = buccinator muscle.
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Figure 1c. Squamous cell carcinoma of the right buccal vestibule. (a) Axial CT scan shows a tumor (arrow) but does not clearly demonstrate which wall is involved. (b) Axial CT scan obtained with the puffed cheek technique shows involvement of both the buccal mucosa (white arrow) and the gingival mucosa (black arrows). (c) Coronal reformatted image obtained with the puffed cheek technique shows involvement of the right cheek (white arrow) and the gingiva (black arrow). * = buccinator muscle.
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Figure 2a. Squamous cell carcinoma of the retromolar trigone. (a) Axial CT scan shows a tumor (arrow), but it is unclear whether there is buccal involvement. (b) Axial CT scan obtained with the puffed cheek technique shows tumoral thickening of the retromolar trigone (arrow). The mucosal surface of the cheek is preserved (arrowheads).
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Figure 2b. Squamous cell carcinoma of the retromolar trigone. (a) Axial CT scan shows a tumor (arrow), but it is unclear whether there is buccal involvement. (b) Axial CT scan obtained with the puffed cheek technique shows tumoral thickening of the retromolar trigone (arrow). The mucosal surface of the cheek is preserved (arrowheads).
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Having the patient move the tongue away from the palate and gingiva allows the tongue to be distinguished from the floor of the mouth and from the gingiva. The gingiva can also be distinguished from the tongue and from the lip (Fig 3). The outline of a tumor is also easier to evaluate (Figs 1–3).
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Figure 3a. Squamous cell carcinoma of the anterior floor of the mouth. (a) Axial CT scan shows a tumor of the right side of the anterior floor of the mouth and the mandibular gingiva (*). It is unclear whether there is involvement of the lower lip (arrowheads). (b) Sagittal reformatted image shows the lower extent of the tumor at the floor of the mouth above the geniohyoid and mylohyoid muscles (arrow), but the tongue is not clearly distinguished from the gingiva. The lower lip and the gingiva are still apposed (arrowheads). (c) Axial CT scan obtained with the puffed cheek technique shows that the anterior floor of the mouth is inflated. The medial limit of the tumor is clearly seen in the midline (arrow). It is still unclear whether there is involvement of the lower lip (arrowheads). (d) Sagittal reformatted image obtained with the puffed cheek technique shows that the tumor involves the gingiva (arrow) but does not involve the tongue. The lower lip is separated from the gingiva and appears preserved (arrowheads). * = inflated buccal vestibule.
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Figure 3b. Squamous cell carcinoma of the anterior floor of the mouth. (a) Axial CT scan shows a tumor of the right side of the anterior floor of the mouth and the mandibular gingiva (*). It is unclear whether there is involvement of the lower lip (arrowheads). (b) Sagittal reformatted image shows the lower extent of the tumor at the floor of the mouth above the geniohyoid and mylohyoid muscles (arrow), but the tongue is not clearly distinguished from the gingiva. The lower lip and the gingiva are still apposed (arrowheads). (c) Axial CT scan obtained with the puffed cheek technique shows that the anterior floor of the mouth is inflated. The medial limit of the tumor is clearly seen in the midline (arrow). It is still unclear whether there is involvement of the lower lip (arrowheads). (d) Sagittal reformatted image obtained with the puffed cheek technique shows that the tumor involves the gingiva (arrow) but does not involve the tongue. The lower lip is separated from the gingiva and appears preserved (arrowheads). * = inflated buccal vestibule.
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Figure 3c. Squamous cell carcinoma of the anterior floor of the mouth. (a) Axial CT scan shows a tumor of the right side of the anterior floor of the mouth and the mandibular gingiva (*). It is unclear whether there is involvement of the lower lip (arrowheads). (b) Sagittal reformatted image shows the lower extent of the tumor at the floor of the mouth above the geniohyoid and mylohyoid muscles (arrow), but the tongue is not clearly distinguished from the gingiva. The lower lip and the gingiva are still apposed (arrowheads). (c) Axial CT scan obtained with the puffed cheek technique shows that the anterior floor of the mouth is inflated. The medial limit of the tumor is clearly seen in the midline (arrow). It is still unclear whether there is involvement of the lower lip (arrowheads). (d) Sagittal reformatted image obtained with the puffed cheek technique shows that the tumor involves the gingiva (arrow) but does not involve the tongue. The lower lip is separated from the gingiva and appears preserved (arrowheads). * = inflated buccal vestibule.
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Figure 3d. Squamous cell carcinoma of the anterior floor of the mouth. (a) Axial CT scan shows a tumor of the right side of the anterior floor of the mouth and the mandibular gingiva (*). It is unclear whether there is involvement of the lower lip (arrowheads). (b) Sagittal reformatted image shows the lower extent of the tumor at the floor of the mouth above the geniohyoid and mylohyoid muscles (arrow), but the tongue is not clearly distinguished from the gingiva. The lower lip and the gingiva are still apposed (arrowheads). (c) Axial CT scan obtained with the puffed cheek technique shows that the anterior floor of the mouth is inflated. The medial limit of the tumor is clearly seen in the midline (arrow). It is still unclear whether there is involvement of the lower lip (arrowheads). (d) Sagittal reformatted image obtained with the puffed cheek technique shows that the tumor involves the gingiva (arrow) but does not involve the tongue. The lower lip is separated from the gingiva and appears preserved (arrowheads). * = inflated buccal vestibule.
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In selected cases, like cheek tumors, a similar result could be obtained with magnetic resonance (MR) imaging. Although the poor temporal resolution of MR imaging does not allow performance of the puffed cheek technique, correct inflation of the buccal vestibule could be achieved with a device (ie, a cannula) placed in the mouth, providing adequate separation of the apposed mucosal surfaces without the risk of undesirable movement and motion artifacts (Fig 4).
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Figure 4a. Tumor of the retromolar trigone with involvement of the buccal mucosa and buccinator muscle. (a) Axial T1-weighted MR image obtained with a cannula in the mouth shows separation of the buccal mucosal surface involved by a tumor (black arrow) and the gingival mucosal surfaces (white arrow). * = signal void of the cannula. (b) Axial T1-weighted MR image obtained with fat saturation and gadolinium contrast material shows the extent of the tumor and the buccal involvement (arrows). (c) Photograph obtained during direct examination of the oral cavity shows the involvement of the buccal mucosa.
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Figure 4b. Tumor of the retromolar trigone with involvement of the buccal mucosa and buccinator muscle. (a) Axial T1-weighted MR image obtained with a cannula in the mouth shows separation of the buccal mucosal surface involved by a tumor (black arrow) and the gingival mucosal surfaces (white arrow). * = signal void of the cannula. (b) Axial T1-weighted MR image obtained with fat saturation and gadolinium contrast material shows the extent of the tumor and the buccal involvement (arrows). (c) Photograph obtained during direct examination of the oral cavity shows the involvement of the buccal mucosa.
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Figure 4c. Tumor of the retromolar trigone with involvement of the buccal mucosa and buccinator muscle. (a) Axial T1-weighted MR image obtained with a cannula in the mouth shows separation of the buccal mucosal surface involved by a tumor (black arrow) and the gingival mucosal surfaces (white arrow). * = signal void of the cannula. (b) Axial T1-weighted MR image obtained with fat saturation and gadolinium contrast material shows the extent of the tumor and the buccal involvement (arrows). (c) Photograph obtained during direct examination of the oral cavity shows the involvement of the buccal mucosa.
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Modified Valsalva Maneuver
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Indications
The modified Valsalva maneuver is basically indicated when a previous quiet respiration examination does not correctly evaluate the location and extent of a hypopharyngeal tumor due to apposition of mucosal surfaces. It may also be useful in examination of the nasopharynx when the pharyngeal recesses are collapsed.
Method
The Valsalva maneuver must be distinguished from the modified Valsalva maneuver. The Valsalva maneuver consists of an expiration against the resistance of the closed glottis. The trachea and subglottis are filled with air, and the laryngeal vestibule is collapsed.
The modified Valsalva maneuver was described by Jonsson (9) in 1934 as "a method for examination of the hypopharynx and upper way passages." Expiration is performed not against the resistance of the closed glottis but against the resistance of pursed lips or a pursed nose. The patient should be able to hold his or her breath for at least 10 seconds. Previous patient training is recommended before the examination to ensure the success of this maneuver.
Technical Parameters
The scanning range is programmed from the hyoid bone to the trachea. A 1-mm section thickness is recommended to enhance the spatial resolution, and the pitch and table speed are selected so as to contain the acquisition time within 10 seconds and avoid motion artifacts. A suggested imaging protocol is summarized in the Table.
Results
The major effects of the modified Valsalva maneuver are to open the glottis and to distend the laryngeal vestibule and piriform sinuses (10) (Fig 5). The true and false vocal cords are abducted and thus are generally poorly depicted. Good separation of the postcricoid and postarytenoid soft tissue from the posterior pharyngeal wall can also be achieved (Fig 6). Misdiagnosed small lesions of the hypopharynx and laryngeal vestibule are more easily identified (Fig 6). Tumor extension to the different walls of the piriform sinus is also more visible, and local staging is more accurate (Fig 7). Some authors have raised the possibility of using this maneuver with fast and ultrafast MR imaging pulse sequences (11–13).
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Figure 5a. Normal hypopharynx. (a) Axial CT scan obtained during quiet respiration shows that the mucosal surfaces of the piriform sinuses are apposed (arrows). (b) Axial CT scan obtained during the Valsalva maneuver shows that the piriform sinuses are inflated and their walls are well depicted (arrows).
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Figure 5b. Normal hypopharynx. (a) Axial CT scan obtained during quiet respiration shows that the mucosal surfaces of the piriform sinuses are apposed (arrows). (b) Axial CT scan obtained during the Valsalva maneuver shows that the piriform sinuses are inflated and their walls are well depicted (arrows).
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Figure 6a. Squamous cell carcinoma of the left piriform sinus. (a) Axial CT scan obtained during quiet respiration shows that the mucosal surfaces of the left piriform sinus are apposed (arrows); therefore, no evident lesion is observed. The postarytenoid soft tissue and the posterior pharyngeal wall are apposed. (b) Axial CT scan obtained during the Valsalva maneuver shows tumoral thickening of the lateral wall of the left piriform sinus (arrows). The postarytenoid soft tissue and the posterior pharyngeal wall are separated and clearly depicted. Arrowhead = level III adenopathy.
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Figure 6b. Squamous cell carcinoma of the left piriform sinus. (a) Axial CT scan obtained during quiet respiration shows that the mucosal surfaces of the left piriform sinus are apposed (arrows); therefore, no evident lesion is observed. The postarytenoid soft tissue and the posterior pharyngeal wall are apposed. (b) Axial CT scan obtained during the Valsalva maneuver shows tumoral thickening of the lateral wall of the left piriform sinus (arrows). The postarytenoid soft tissue and the posterior pharyngeal wall are separated and clearly depicted. Arrowhead = level III adenopathy.
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Figure 7a. Squamous cell carcinoma of the right side of the hypopharynx. (a) Axial CT scan obtained during quiet respiration shows a tumor (*). Apposition of the mucosal surfaces does not allow identification of the involved wall. (b) Axial CT scan obtained during the Valsalva maneuver shows the tumor, which involves the right aryepiglottic fold (*).
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Figure 7b. Squamous cell carcinoma of the right side of the hypopharynx. (a) Axial CT scan obtained during quiet respiration shows a tumor (*). Apposition of the mucosal surfaces does not allow identification of the involved wall. (b) Axial CT scan obtained during the Valsalva maneuver shows the tumor, which involves the right aryepiglottic fold (*).
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When expiration is performed against the resistance of a pursed nose, another noticeable effect is the possibility of opening the pharyngeal recess (Rosenmüller fossa) with the ability to determine whether one or two walls are invaded by a nasopharyngeal tumor (Fig 8). Useful information for local staging according to the TNM classification (14) is also provided.
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Figure 8a. Differentiated squamous cell carcinoma of the nasopharynx. (a) Axial CT scan obtained during quiet respiration shows a tumor of the right and posterior walls of the nasopharynx (arrow). The left margin of the lesion is not clearly seen. (b) Axial CT scan obtained during the Valsalva maneuver shows that the left and posterior walls of the nasopharynx are separated. The tumor is located on the posterior wall (black arrows) and right wall (white arrows). The left wall is preserved (arrowheads).
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Figure 8b. Differentiated squamous cell carcinoma of the nasopharynx. (a) Axial CT scan obtained during quiet respiration shows a tumor of the right and posterior walls of the nasopharynx (arrow). The left margin of the lesion is not clearly seen. (b) Axial CT scan obtained during the Valsalva maneuver shows that the left and posterior walls of the nasopharynx are separated. The tumor is located on the posterior wall (black arrows) and right wall (white arrows). The left wall is preserved (arrowheads).
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Phonation
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Indications
Phonation is indicated when the true and false vocal cords are not clearly depicted and when the exact location of a laryngeal tumor remains undefined following a quiet respiration examination. The true vocal cords could be apposed and indistinguishable from one another when the acquisition is performed during apnea. On the other hand, they may be abducted and thus not visible when the acquisition is performed during quiet respiration.
Method
This maneuver is performed by having the patient say "e" uniformly for at least 10 seconds. Prior patient training is recommended to ensure the success of the maneuver and to reduce motion artifacts.
Technical Parameters
The scanning range is programmed from the hyoid bone to the trachea. A 1-mm section thickness is essential to ensure optimal spatial resolution of axial sections and coronal reformatted images. The pitch and table speed are selected so as to contain the acquisition time within 10 seconds. A suggested imaging protocol is summarized in the Table.
Results
With phonation, the true and false vocal cords are easier to depict than with quiet respiration and the laryngeal ventricles filled with air become more visible (Fig 9). The true and false vocalcords are adducted and tense; consequently, abnormal thickness of a true vocal cord is more easily recognized (Fig 10). Visualization of the laryngeal ventricles allows more accurate determination of the location of a supraglottic tumor (above the ventricles) or a glottic tumor (below the ventricles) (Fig 11).
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Figure 9a. Normal larynx. (a) Axial CT scan shows the normal appearance of the larynx during quiet respiration. The true vocal cords are abducted. (b) Volume-rendered image shows the upper airways during quiet respiration. The true and false vocal cords are poorly seen (arrows). (c) Axial CT scan obtained during phonation shows that the true vocal cords are thin and adducted. The ventricles are properly inflated (*). (d) Volume-rendered laryngogram obtained during phonation clearly shows the true (arrows) and false (*) vocal cords. The laryngeal ventricles are well demonstrated (arrowheads). The piriform sinuses are inflated.
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Figure 9b. Normal larynx. (a) Axial CT scan shows the normal appearance of the larynx during quiet respiration. The true vocal cords are abducted. (b) Volume-rendered image shows the upper airways during quiet respiration. The true and false vocal cords are poorly seen (arrows). (c) Axial CT scan obtained during phonation shows that the true vocal cords are thin and adducted. The ventricles are properly inflated (*). (d) Volume-rendered laryngogram obtained during phonation clearly shows the true (arrows) and false (*) vocal cords. The laryngeal ventricles are well demonstrated (arrowheads). The piriform sinuses are inflated.
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Figure 9c. Normal larynx. (a) Axial CT scan shows the normal appearance of the larynx during quiet respiration. The true vocal cords are abducted. (b) Volume-rendered image shows the upper airways during quiet respiration. The true and false vocal cords are poorly seen (arrows). (c) Axial CT scan obtained during phonation shows that the true vocal cords are thin and adducted. The ventricles are properly inflated (*). (d) Volume-rendered laryngogram obtained during phonation clearly shows the true (arrows) and false (*) vocal cords. The laryngeal ventricles are well demonstrated (arrowheads). The piriform sinuses are inflated.
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Figure 9d. Normal larynx. (a) Axial CT scan shows the normal appearance of the larynx during quiet respiration. The true vocal cords are abducted. (b) Volume-rendered image shows the upper airways during quiet respiration. The true and false vocal cords are poorly seen (arrows). (c) Axial CT scan obtained during phonation shows that the true vocal cords are thin and adducted. The ventricles are properly inflated (*). (d) Volume-rendered laryngogram obtained during phonation clearly shows the true (arrows) and false (*) vocal cords. The laryngeal ventricles are well demonstrated (arrowheads). The piriform sinuses are inflated.
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Figure 10a. Tumorlike nodules of the true vocal cords that manifested as hoarseness. (a) Axial CT scan obtained during quiet respiration shows apposition of the thickened true vocal cords (arrows). (b) Axial CT scan obtained during phonation shows a nodule of the right true vocal cord (arrow). The nodule is clearly visible due to tension of the true vocal cords. (c) Volume-rendered laryngogram obtained during phonation shows the thickening of the true vocal cords (black arrows). The false vocal cords (white arrows) and laryngeal ventricles (arrowheads) are clearly seen. (d) Coronal reformatted image obtained during phonation shows the thickening of the true vocal cords (arrows). The false vocal cords (*) and laryngeal ventricles (arrowheads) are also seen. (e) Image from endoscopy shows two lesions of the true vocal cords. Histopathologic evaluation revealed Reinke edema (pseudocysts).
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Figure 10b. Tumorlike nodules of the true vocal cords that manifested as hoarseness. (a) Axial CT scan obtained during quiet respiration shows apposition of the thickened true vocal cords (arrows). (b) Axial CT scan obtained during phonation shows a nodule of the right true vocal cord (arrow). The nodule is clearly visible due to tension of the true vocal cords. (c) Volume-rendered laryngogram obtained during phonation shows the thickening of the true vocal cords (black arrows). The false vocal cords (white arrows) and laryngeal ventricles (arrowheads) are clearly seen. (d) Coronal reformatted image obtained during phonation shows the thickening of the true vocal cords (arrows). The false vocal cords (*) and laryngeal ventricles (arrowheads) are also seen. (e) Image from endoscopy shows two lesions of the true vocal cords. Histopathologic evaluation revealed Reinke edema (pseudocysts).
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Figure 10c. Tumorlike nodules of the true vocal cords that manifested as hoarseness. (a) Axial CT scan obtained during quiet respiration shows apposition of the thickened true vocal cords (arrows). (b) Axial CT scan obtained during phonation shows a nodule of the right true vocal cord (arrow). The nodule is clearly visible due to tension of the true vocal cords. (c) Volume-rendered laryngogram obtained during phonation shows the thickening of the true vocal cords (black arrows). The false vocal cords (white arrows) and laryngeal ventricles (arrowheads) are clearly seen. (d) Coronal reformatted image obtained during phonation shows the thickening of the true vocal cords (arrows). The false vocal cords (*) and laryngeal ventricles (arrowheads) are also seen. (e) Image from endoscopy shows two lesions of the true vocal cords. Histopathologic evaluation revealed Reinke edema (pseudocysts).
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Figure 10d. Tumorlike nodules of the true vocal cords that manifested as hoarseness. (a) Axial CT scan obtained during quiet respiration shows apposition of the thickened true vocal cords (arrows). (b) Axial CT scan obtained during phonation shows a nodule of the right true vocal cord (arrow). The nodule is clearly visible due to tension of the true vocal cords. (c) Volume-rendered laryngogram obtained during phonation shows the thickening of the true vocal cords (black arrows). The false vocal cords (white arrows) and laryngeal ventricles (arrowheads) are clearly seen. (d) Coronal reformatted image obtained during phonation shows the thickening of the true vocal cords (arrows). The false vocal cords (*) and laryngeal ventricles (arrowheads) are also seen. (e) Image from endoscopy shows two lesions of the true vocal cords. Histopathologic evaluation revealed Reinke edema (pseudocysts).
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Figure 10e. Tumorlike nodules of the true vocal cords that manifested as hoarseness. (a) Axial CT scan obtained during quiet respiration shows apposition of the thickened true vocal cords (arrows). (b) Axial CT scan obtained during phonation shows a nodule of the right true vocal cord (arrow). The nodule is clearly visible due to tension of the true vocal cords. (c) Volume-rendered laryngogram obtained during phonation shows the thickening of the true vocal cords (black arrows). The false vocal cords (white arrows) and laryngeal ventricles (arrowheads) are clearly seen. (d) Coronal reformatted image obtained during phonation shows the thickening of the true vocal cords (arrows). The false vocal cords (*) and laryngeal ventricles (arrowheads) are also seen. (e) Image from endoscopy shows two lesions of the true vocal cords. Histopathologic evaluation revealed Reinke edema (pseudocysts).
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Figure 11a. Squamous cell carcinoma of the right side of the glottis. (a) Axial CT scan obtained during quiet respiration shows a tumor of the anterior commissure (arrow). (b) Coronal reformatted image obtained during quiet respiration shows the tumor (*). However, the true and false vocal cords are poorly seen, so the local extent of the tumor remains undefined. (c) Volume-rendered image shows the upper airways during quiet respiration. The larynx forms a wide airway indistinguishable from the trachea below. The scalloping of the airway corresponds to the lesion (arrow). (d) Coronal reformatted image obtained during phonation shows the right laryngeal ventricle (arrow). The tumor (*) is located solely below the ventricle; therefore, involvement of the supraglottic structures is ruled out. (e) Volume-rendered laryngogram obtained during phonation shows the right laryngeal ventricle (arrowhead). The subglottic scalloping represents the lower extent of the tumor (arrows).
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Figure 11b. Squamous cell carcinoma of the right side of the glottis. (a) Axial CT scan obtained during quiet respiration shows a tumor of the anterior commissure (arrow). (b) Coronal reformatted image obtained during quiet respiration shows the tumor (*). However, the true and false vocal cords are poorly seen, so the local extent of the tumor remains undefined. (c) Volume-rendered image shows the upper airways during quiet respiration. The larynx forms a wide airway indistinguishable from the trachea below. The scalloping of the airway corresponds to the lesion (arrow). (d) Coronal reformatted image obtained during phonation shows the right laryngeal ventricle (arrow). The tumor (*) is located solely below the ventricle; therefore, involvement of the supraglottic structures is ruled out. (e) Volume-rendered laryngogram obtained during phonation shows the right laryngeal ventricle (arrowhead). The subglottic scalloping represents the lower extent of the tumor (arrows).
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Figure 11c. Squamous cell carcinoma of the right side of the glottis. (a) Axial CT scan obtained during quiet respiration shows a tumor of the anterior commissure (arrow). (b) Coronal reformatted image obtained during quiet respiration shows the tumor (*). However, the true and false vocal cords are poorly seen, so the local extent of the tumor remains undefined. (c) Volume-rendered image shows the upper airways during quiet respiration. The larynx forms a wide airway indistinguishable from the trachea below. The scalloping of the airway corresponds to the lesion (arrow). (d) Coronal reformatted image obtained during phonation shows the right laryngeal ventricle (arrow). The tumor (*) is located solely below the ventricle; therefore, involvement of the supraglottic structures is ruled out. (e) Volume-rendered laryngogram obtained during phonation shows the right laryngeal ventricle (arrowhead). The subglottic scalloping represents the lower extent of the tumor (arrows).
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Figure 11d. Squamous cell carcinoma of the right side of the glottis. (a) Axial CT scan obtained during quiet respiration shows a tumor of the anterior commissure (arrow). (b) Coronal reformatted image obtained during quiet respiration shows the tumor (*). However, the true and false vocal cords are poorly seen, so the local extent of the tumor remains undefined. (c) Volume-rendered image shows the upper airways during quiet respiration. The larynx forms a wide airway indistinguishable from the trachea below. The scalloping of the airway corresponds to the lesion (arrow). (d) Coronal reformatted image obtained during phonation shows the right laryngeal ventricle (arrow). The tumor (*) is located solely below the ventricle; therefore, involvement of the supraglottic structures is ruled out. (e) Volume-rendered laryngogram obtained during phonation shows the right laryngeal ventricle (arrowhead). The subglottic scalloping represents the lower extent of the tumor (arrows).
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Figure 11e. Squamous cell carcinoma of the right side of the glottis. (a) Axial CT scan obtained during quiet respiration shows a tumor of the anterior commissure (arrow). (b) Coronal reformatted image obtained during quiet respiration shows the tumor (*). However, the true and false vocal cords are poorly seen, so the local extent of the tumor remains undefined. (c) Volume-rendered image shows the upper airways during quiet respiration. The larynx forms a wide airway indistinguishable from the trachea below. The scalloping of the airway corresponds to the lesion (arrow). (d) Coronal reformatted image obtained during phonation shows the right laryngeal ventricle (arrow). The tumor (*) is located solely below the ventricle; therefore, involvement of the supraglottic structures is ruled out. (e) Volume-rendered laryngogram obtained during phonation shows the right laryngeal ventricle (arrowhead). The subglottic scalloping represents the lower extent of the tumor (arrows).
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In the past, this technique was widely used as part of a tomographic examination of the larynx (15). Examinations performed with this technique and older conventional CT were often affected by motion artifact. Presently, the spectacular decrease in CT acquisition time has reduced motion artifacts so that this technique can be routinely performed with a low failure rate.
According to Held and Breit (13), similar results may be achieved with MR imaging performed with ultrafast pulse sequences.
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Open Mouth Technique
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Indications
The open mouth technique is indicated when a tumor of the oral cavity and oropharynx is not clearly visible because of dental amalgam artifact. An x-ray beam crossing dental amalgam is submitted to an attenuation equivalent to that of lead filtration. Tilting the gantry and scanning above and below the dental amalgam are a common procedure (5). However, with this technique a substantial area still remains unexplored, whereas some areas are irradiated twice. Another solution is to obtain additional scans through the open mouth.
Method
The patient is asked to open the mouth. A device (ie, a 50-mL syringe) is then placed between the teeth to ensure correct immobilization. The acquisition is performed during quiet respiration.
Technical Parameters
The scanning range is programmed through the open mouth from the maxilla to the mandible. A 3-mm section thickness is selected, as multiplanar reformation is not required for such a small acquisition volume. A suggested imaging protocol is summarized in the Table.
Results
Some areas shadowed by dental artifacts become visible, in particular the soft palate but also the cheeks, the gingiva, and the upper part of the mobile tongue. Previously poorly depicted tumors can also be highlighted with adequate contrast; consequently, local staging is more accurate (Fig 12).
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Figure 12a. Squamous cell carcinoma of the right wall of the oropharynx. (a) Axial CT scan shows that the right part of the oropharynx (*) is poorly seen due to dental amalgam artifact, which results in blind areas and poor contrast. Arrow = adenopathy. (b) Tomogram obtained with the open mouth technique shows the levels for performing additional CT with the mouth open. (c) Axial CT scan obtained through the open mouth shows that the previously shadowed areas are visible and the contrast is improved. A tumor is evident (arrow).
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Figure 12b. Squamous cell carcinoma of the right wall of the oropharynx. (a) Axial CT scan shows that the right part of the oropharynx (*) is poorly seen due to dental amalgam artifact, which results in blind areas and poor contrast. Arrow = adenopathy. (b) Tomogram obtained with the open mouth technique shows the levels for performing additional CT with the mouth open. (c) Axial CT scan obtained through the open mouth shows that the previously shadowed areas are visible and the contrast is improved. A tumor is evident (arrow).
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Figure 12c. Squamous cell carcinoma of the right wall of the oropharynx. (a) Axial CT scan shows that the right part of the oropharynx (*) is poorly seen due to dental amalgam artifact, which results in blind areas and poor contrast. Arrow = adenopathy. (b) Tomogram obtained with the open mouth technique shows the levels for performing additional CT with the mouth open. (c) Axial CT scan obtained through the open mouth shows that the previously shadowed areas are visible and the contrast is improved. A tumor is evident (arrow).
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Conclusions
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In some cases, routine imaging examination of head and neck malignancies does not yield all of the necessary data, even with the most advanced imaging technique. Additional scans obtained with dynamic maneuvers can depict some lesions that were previously nonidentified due to apposition of anatomic structures or the presence of dental amalgam artifacts. The open mouth technique, puffed cheek technique, and modified Valsalva maneuver should be performed in these situations. In cases of laryngeal tumors, phonation can shed light on the exact anatomic location and extent of the lesion. The additional x-ray dose should be carefully weighed against the expected improvement of the diagnostic value; therefore, these dynamic maneuvers should be performed only after an examination with inconclusive results.
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References
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S. Yale
Author's Reply
Clin. Med. Res.,
May 1, 2005;
3(2):
55 - 56.
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Abstract
LEARNING OBJECTIVES
