ww.sciencedirect.com

i n d i a n j o u r n a l o f d e n t i s t r y 4 ( 2 0 1 3 ) 1 2 9e1 3 6

Available online at w

journal homepage: www.elsevier .com/locate/ i jd

Original Article

Diagnostic significance of ultrasonography ininvestigations of swellings of head and neckregion e A clinico-imaging study

Vemanna Naveen Shankar a,*, Naveen Shankar Ashwini a, Gopa Kumar b,Subhas Babu c

aAssociate Professor, Kothiwal Dental College Research Centre and Hospital, Kanth Road, Moradabad,

Uttar Pradesh, Indiab Professor and HOD, Department of Oral Medicine & Radiology, Mahatma Gandhi Dental College and Hospital,

Sitapura, Tonk Road, Jaipur, Rajasthan, IndiacProfessor and HOD, Department of Oral Medicine & Radiology, A B Shetty Memorial Institute of Dental Sciences,

Deralakatte, Mangalore, Karnataka, India

a r t i c l e i n f o

Article history:

Received 24 September 2012

Accepted 16 May 2013

Keywords:

Ultrasonography

Swellings

Echo intensity

Posterior echoes

* Corresponding author. No# 110, 5th WaRoad, Bagepalli, Chikkaballapur 561207,Tel.: þ91 9458524247, þ91 8150 282521.

E-mail address: vnaveenshankar@gmaShankar).0975-962X/$ e see front matter ª 2013 Indiahttp://dx.doi.org/10.1016/j.ijd.2013.05.004

a b s t r a c t

Objectives: A study was conducted with an aim to evaluate the reliability, diagnostic efficacy

of ultrasonography in head and neck swelling and familiarize with the clinical application

of ultrasonography as an investigative modality for diagnosis of head and neck swellings.

Methodology: 90 randomly selected volunteering patients with obvious head and neck

swellings of both gender and any age group who reported to the Dept. of Oral Medicine and

Radiology, A.B. Shetty Memorial Institute of Dental Sciences, Deralakatte were included in

the study. After a clinical diagnosis, they were subjected to ultrasonographic investigation

and a diagnosis was arrived at. These findings were compared with final diagnosis. The

data obtained were statistically analysed using sensitivity and specificity tests.

Results: The sensitivity and specificity of ultrasonography in inflammatory swellings was

96.5%. For cystic, swellings of muscular origin, lymph node swellings and malignant

neoplasms it was 100%. In addition, for benign neoplasms it was 92.86%.

Conclusion: Ultrasonography is a valuable and accurate diagnostic tool in diagnosis of head

and neck swellings. Even though ultrasonographic pictures were consistent and are, reli-

able they should be used only as an added informative investigation tool in diagnosing

benign neoplasms, malignant neoplasms and swellings of lymph node origin.

ª 2013 Indian Journal of Dentistry. All rights reserved.

rd, National CollegeKarnataka, India.

il.com (V. Naveen

n Journal of Dentistry. Al

1. Introduction

Ultrasoundwas introduced into themedical field around 1940s,

since then it has beenwidelyused. Ithas foundmanyadherents

in thefieldsofophthalmologyandobstetricsandgynaecology. It

hasproved invaluable incardiologyandabdominal diseases.1 In

recent years, the role of ultrasonography in the head and neck

l rights reserved.

i n d i a n j o u rn a l o f d e n t i s t r y 4 ( 2 0 1 3 ) 1 2 9e1 3 6130

has expanded dramatically.2 It is used in establishing differen-

tial diagnosis of cystic neck masses, solid masses and lymph-

adenopathies.3 It not only serves for thedifferentiationbetween

benign and malignant lymphadenopathy but also between

intraglandular and extraglandular abnormalities of the salivary

glands, with 90e95% accuracy. Ultrasound can also be used for

the thyroid lesions, remaining cervical structures, particularly

space occupying lesions.4

Ultrasonography is a simple, non-invasive investigative

technique in the diagnosis of various lesions. The information

obtained from ultrasonography can be superior to that ob-

tained by plain and contrast radiography and is comparable

with that obtained by computerized tomography.5

Taking into consideration the various advantages of ul-

trasonography and its ability to evaluate the extent of infor-

mation available in various types of head and neck swellings,

the present study was undertaken.

2. Methodology

Ninety cases with obvious head and neck swellings were

randomly selected for the study. Detailed case history was

taken and arrived at clinical diagnosis. Based on the clinical

diagnosis, swellings were categorised into 5 groups ie In-

flammatory swellings, Cystic swellings, Muscular swellings,

Lymph nodes and Neoplastic swellings that included both

benign and malignant lesions.

Relevant non-invasive investigations like CT, MRI were

performed wherever indicated. Ultrasonographic investiga-

tion was carried out using a GE Wipro 400 Prologic Series with

a Superficial Transducer Probe at a frequency range of

7.5e11 MHz. Five features were considered in describing the

Graph 1 e Percentage dis

ultrasonographic images of swellings of head and neck in

accordance with Mayumi Shimizu et al (1999).

Shape: oval, lobular, polygonal and irregular.

Boundary: very clear, relatively clear, partially unclear and ill-

defined.

Echo intensity: anechoic, slightly hypoechoic, hypoechoic,

and hyperechoic.

Distribution of internal echoes: homogeneous, multiple

anechoic, heterotrophic with characteristic, heterotrophic

without characteristic, and

Posterior echoes: enhanced, unchanged and attenuated.6

The obtained results were tabulated and statistically ana-

lysed by considering the final diagnosis as gold standard.

Sensitivity and specificity values were calculated to evaluate

reliability and diagnostic efficacy of ultrasonography as an

investigating tool.

3. Results

Out of 90 patients with head and neck swellings:

22 were inflammatory swellings (24 44%);

21 were benign neoplasms (23.33%);

19 were cystic swellings (21.11%);

16 were lymph node swellings (17.77%);

8 swellings were of muscle origin (8.88%); and

4 were malignant neoplasms (4.47%) (Graph 1).

Out of 90 cases, 24.44% were inflammatory swellings,

which showed signs of inflammation. They were either from

odontogenic origin 68.18%, or of non-odontogenic origin

tribution of swelling.

i n d i a n j o u r n a l o f d e n t i s t r y 4 ( 2 0 1 3 ) 1 2 9e1 3 6 131

31.82%. On ultrasonography inflammatory swellings were

irregular by shape (64%) with ill-defined borders (46%) and the

echoes intensity were slightly hypoechoic (40.9%) to hypo-

echoic (40.9%). The internal echoes was heterotrophic without

characteristic (68.8%) and posterior echoeswere unchanged in

(86.2%) (Table 1).

The sensitivity and specificity of both clinical and sono-

graphic diagnosis are given in Table 2.

Benign neoplasm’s comprised of 23.33%. Sonographically

these lesions were polygonal (33.33%) to lobular in shape

(28.57%), hypoechoic (66.7%), with relatively clear borders

(57.14%), internal density ranged from homogeneous

(38.1%) to heterotrophic without characteristic (47.62%)

and no changes were appreciated posterior to the

lesion (Table 1).

21.11% of all the cases were cystic swellings, of which cyst

of odontogenic origin formed 69% and non-odontogenic cysts

formed 21%. Ultrasonography of cystic lesions had very clear

borders (78.9%), oval in shape (78.9%), their internal echo

density was anechoic (84.2%), homogeneous internal echo

density was noted (78.9%) and all the lesions had posterior

acoustic enhancement (Table 1).

Swellings of muscle origin comprised of 8.88% all patients.

Sonographically all the swellings had relatively clear borders,

polygonal in shape, had hypoechoic heterotrophic with

characteristic internal echo density and posterior echos were

unchanged (Table 1).

Sixteen were lymph node swellings (17.77%). They

appeared as homogeneous (64.29%), hypoechoic (71.42%), oval

in shape (57.14%), with clear border (50%), and no changewere

noted in the posterior echo intensity (Table 1).

4.47% malignant lesions were studied, which sono-

graphically had relatively clear borders (75%), had polygonal

shape (75%), echo intensity was varying from slightly hypo-

echoic (50%) to hypoechoic (50%), internal density were mul-

tiple anechoic (50%) to heterotrophic without characteristic

(50%) and no change was noted posteriorly (Table 1).

4. Discussion

Ultrasonography is a safe reliable method of examination

that causes little patient discomfort, is well established

non-invasive imaging procedure for soft tissue masses such

as in thyroid upper abdominal region.5,7 In recent years the

role of ultrasound in the head and neck has expanded

dramatically. We can now image neck structures in exqui-

site detail.6

4.1. Inflammatory swellings

Among 22 inflammatory swellings, 15 (68.18%) were of odon-

togenic origin and 7 (31.82%.) were from non-odontogenic

origin.

Sigert in his study of inflammatory soft tissue swellings

classified the sonographic images into five types Edema,

Infiltrate, Preabscess, Echo-poor abscess and echo-free ab-

scess.8 In the present study 14 cases of abscess sono-

graphically appeared as ill-defined hypoechoic mass with

heterotrophic without characteristic appearance i.e. with very

few internal echoes which is in accordance with the descrip-

tion given by Siegert8 and Benjamin9 (Fig. 1).

One patient who was diagnosed as cellulitis clinically, on

ultrasonogram showed an ill-defined homogeneous hypo-

echoic mass with difficulty in delineating anatomical struc-

tures and was histopathologically diagnosed as extra nodal

lymphoma.

Non-odontogenic inflammatory swellings consisted of 4

obstructive submandibular sialadenitis cases and 3 cases

were of Parotitis on clinical diagnosis.

None of the 4 cases of submandibular sialadenitis revealed

calculi on conventional radiographs. On ultrasonogram they

typically appeared as duct dilation proximal to an obstruction.

2 cases of calculi obstruction appeared as hyperechoic foci

with distal acoustic shadowing where as 2 cases of fibrotic

obstruction appeared as hyperechoic foci without posterior

shadowing. These findings were consistent with previous

studies by Partridge et al (1986),10 Yoshimura et al (1989),11

Traxler et al (1992),12 Van den akker (1988).13

Alyas et al (2005)14 said that acute parotitis appeared as

enlarged hypoechoic gland and there was coarsening of gland

texture. Chronic parotitis appeared as coarse, reticulated

patternwithmultiple, rounded, hypoechoic foci seenwithin the

gland parenchyma. These hypoechoic areas represent areas of

non-obstructive sialectasis. In our study, out of three cases two

cases had coarsening of glandular parenchyma with multiple

anechoic areas as seen in chronic parotitis described by Alyas

et al (2005),14 Traxler et al (1992),12 Howlett (2003).15 One case

showed enlargement of gland with coarsening of glandular

texture which was seen in the initial stages of Parotitis as

described by Howlett (2003),15 and Alyas et al (2005).14

On comparison, though clinical diagnosis was not condu-

cive with final diagnosis in eight patients, where as the

sonographic diagnosis of all the cases matched with the final

diagnosis hence, both sensitivity and specificity of sono-

graphic diagnosis in our study was 100%, which is not in

accordance with the previous studies by Alyas et al (2005),14

Traxler et al (1992),12 Howlett (2003).15 This variation is prob-

ably because of the less sample size in our study.

Hence, the sensitivity and specificity of clinical diagnosis

was 47.62% and 100% respectively where as the sonographic

diagnosis had 96.5% sensitivity and specificity in diagnosing

inflammatory swellings of head and neck. This is in concur-

rence with the previous studies done by Siegert (1987),8 Yusa

et al (2002),16 Benjamin (2005),9 Vivek (2006).17

4.2. Cystic swellings

In the present study 19 cystic swellings (21.11%) were visual-

ized. Cyst on sonogramappeared as anechoicwhich are due to

the fact that, liquids are homogeneous and there are no

structures to produce internal echoes, there is little or no

attenuation of sound as it passes through, which creates

enhanced transmission of sound at the distal aspect of cystic

mass. If the cyst becomes infected then the content of the

lesion can produce some echoes producing a hypoechoic

picture as described by Ishikawa et al (1983),7 Pogrel (1982)5

and Osama and Corney (1993).18

In our study all the patients had posterior enhancement

(100%) and 16 cases were totally anechoic (84.2%) with

Table 1 e Comparison of different sonographic features in different sample groups.

Inflammatory swellings Cystic swellings Muscle origin Lymph nodes origin Benign neoplasms Malignant neoplasm

N % N % N % N % N % N %

Boundary Very clear 2 9.2 15 78.9 6 28.6

Relatively clear 7 31.8 4 21.1 4 100 7 50 12 57.14 3 75

Partially unclear 5 23 3 21.42 2 9.5 1 25

Ill-defined 10 46 4 28.58 4 19.05

Shape Oval 2 9.2 15 78.9 8 57.14 4 19.05

Lobular 1 4.6 1 5.3 1 7.14 6 28.57

Polygonal 5 23 3 15.8 4 100 1 7.14 7 33.33 3 75

Irregular 14 64.2 4 28.58 1 4.76 1 25

Echo

intensity

Anechoic 1 4.6 16 84.2 2 9.5

Slightly

hypoechoic

9 40.9 3 15.8 4 28.58 5 23.91 2 50

Hypoechoic 9 40.9 4 100 10 71.42 14 66.7 2 50

Hyperechoic 3 13.6

Internal

echoes

Homogeneous 6 27.3 15 78.9 9 64.29 8 38.1

Multiple anechoic 1 4.6 1 4.76 2 50

Heterotropic with

characteristic

4 100 2 9.5

Heterotropic

without

characteristic

15 68.8 4 21.1 5 35.71 10 47.62 2 50

Posterior

echoes

Enhanced 1 4.6 19 100 5 23.81

Unchanged 19 86.2 4 100 14 100 16 76.19 4 100

Attenuated 2 9.2

india

njo

urnalofdentis

try

4(2

013)129e136

132

Table

2e

Com

pariso

nofSensitivityandsp

ecificity

ofclin

icalandUSG

diagnosisin

differentsa

mple

gro

ups.

Inflamm

atory

swellings

Cystic

swellings

Musc

leorigin

Lym

phnodesorigin

Benignneoplasm

’sMalignantneoplasm

’s

Clinical

diagnosis

USG

diagnosis

Clinical

diagnosis

USG

diagnosis

Clinical

diagnosis

USG

diagnosis

Clinical

diagnosis

USG

diagnosis

Clinical

diagnosis

USG

diagnosis

Clinical

diagnosis

USG

diagnosis

Sensitivity

47.6

100

93.75

100

100

100

100

100

71.43

92.86

100

100

Specificity

100

100

100

100

100

100

66.7

100

92.86

100

100

Fig. 1 e Ill-defined hypoechoic lesion with heterotrophic

without characteristic appearance.

Fig. 2 e Well-defined, homogeneous anechoic internal

structure with posterior acoustic enhancement.

i n d i a n j o u r n a l o f d e n t i s t r y 4 ( 2 0 1 3 ) 1 2 9e1 3 6 133

homogeneous internal echoes (78.9%). These findings were

consistent with the studies by Ishikwa et al (1983),7 Pogrel

(1982)5 and Osama and Corney (1993),18 (Fig. 2).

However, 3 cases (15.8%) had hypoechoic internal echoes

which could be because of infectionwhich has produced some

internal echoes.

In our study, 3 branchial cleft cyst and one sebaceous cyst

were studied. Branchial cyst classically appeared as anechoic

homogeneous well-defined mass with posterior acoustic

enhancement. The sebaceous cyst appeared as superficial

well-defined hypoechoic mass with posterior acoustic

i n d i a n j o u rn a l o f d e n t i s t r y 4 ( 2 0 1 3 ) 1 2 9e1 3 6134

enhancement. Comparing the clinical diagnosis with final

diagnosis one patient’s clinical diagnosis did not correspond

with the final diagnosis and on comparison of final diagnosis

with sonographic diagnosis all the sonographic diagnosis did

correspond with the final diagnosis.

In the present study, since the sonographic diagnosis in all

the cases did correspond with the final diagnosis. The sensi-

tivity and specificity of sonography in diagnosing cysts of head

and neck was 100%. These results are concurrent with the

studies done by Ishikwa et al (1983),7 Pogrel (1982),5 and

Osama and Corney (1993).18

4.3. Swellings of muscle origin

8 cases (8.88%) of Massetric hypertrophy were included in our

study. Masseter on sonogram appears as homogeneous

structure lying adjacent to the echogenic band of the

mandible and themusclewidthwasmeasured both in relaxed

and contracted state by asking the patient to clench his teeth

and normal range for transverse dimension is 8.5e13.5 mm as

per Emshoff et al (2003),19 Morse et al (1989),20 and Ariji et al

(2004).21 In our study, all the volunteers had relatively clear

borders (100%), and they appeared as homogeneous with

hypoechoic band (100%) with the transverse measurement of

15 mme21 mm (Table 1).

The sonographic and clinical diagnoses of all cases are in

conformity with the final diagnosis so the sensitivity and

specificity of sonographic and clinical diagnosis was 100% in

our study (Fig. 3).

Our results could not be compared as we failed to find

studies on sonographic features of Massetric hypertrophy in

the literature. But the muscle measurement was significantly

greater than the normal range (8.5e13.5 mm) as described by

Morse et al (1989).20

4.4. Swellings of lymph node origin

Swellings of lymph node origin comprised of sixteen cases

(17.77%). Reactive lymph nodes tend to be oval or elongated in

shape, appear hypoechoic with or without the presence of

echogenic hilus. The ratio of the long to short axis (L/S) ratio

Fig. 3 e Clear borders with homogeneous hypoechoic band.

will be less than 0.5 as per Yuasa et al (2000),22 Takashima et al

(1997),23 Quetz et al (1991),24 and Atula et al (1996).25

Neoplastic node will have indefinite internal or hilar

echoes, measures 10 mm ormore in the short axis, and a ratio

of the long to short axis (L/S ratio) of 0.5 or more according to

Yuasa et al (2000).22 On sonogram, 50% had relatively clear

border, 28.58% ill-defined and partially unclear was seen in

21.42%. 57.14% had oval shape and 28.58% had ill-defined

shape; 71.42% were hypoechoic. 64.29% was homogeneous

(Fig. 4) (Table 1).

Six patients had neoplastic enlargement of lymph nodes

most of which had heterogeneous internal structure with loss

of hilumand their shapewasmore than 10mm.Thesefindings

are similar to that of Sumi et al (2001),26 Yuasa et al (2000),22

Takashimaet al (1997),23Quetzet al (1991),24Atulaet al (1996).25

Comparing the clinical diagnosis with final diagnosis one

patient’s clinical diagnosis did not match with the final diag-

nosis and on comparison of final diagnosis with sonographic

diagnosis all the sonographic diagnosis was in agreement

with the final diagnosis.

The sensitivity 73% and specificity 78% of sonographic

diagnosis of lymph nodes in differentiating benign and ma-

lignant enlargements increased on combining sonography

with F N A C to sensitivity of 85% and specificity of 100%

Sumi et al.26

In our study, the sensitivity and specificity of sonographic

diagnosis was 100%. which could be attributed to bias in the

sample selection, as we included only patients with the

swelling or fullness in that region, which on sonogram was

more than 10 mm, which were considered as malignant ac-

cording to the previous studies by Sumi et al (2001),26 Yuasa et

al (2000),22 Takashima et al (1997),23 Quetz et al (1991),24 Atula

et al (1996).25

4.5. Benign neoplasms

Twenty-one (23.33%) were benign neoplasms which included

Pleomorphic adenomas (11), lipomas (4) Neuroma (2),

Fig. 4 e Well-defined border, oval in shape, homogeneous

hypoechoic with hilus.

Fig. 6 e Irregular and poorly defined margins,

heterogeneous internal structures.

i n d i a n j o u r n a l o f d e n t i s t r y 4 ( 2 0 1 3 ) 1 2 9e1 3 6 135

Haemangioma (1) and one extra nodal lymphoma. Pleomor-

phic adenomas on sonogram appeared as being rounded,

circumscribed and hypoechoic, with distal acoustic

enhancement. Larger lesions may develop more atypical fea-

tures, with a heterogeneous internal architecture, cystic

changes, loss of clarity of margins and may mimic malig-

nancy. Longstanding tumours may calcify and are at risk of

malignant degeneration.10,14,15,26

In the present study, eight Pleomorphic adenomas (72%)

had clear borders their shape was lobular in 5 (45%) and

polygonal in 6 (54%). 10 (90%) patients had Heterotrophic

characteristic without and few of them had calcifications. Of

the 11 Pleomorphic adenomas, only 6 clinically diagnosed

cases were corresponding with final diagnosis, where as

sonographically three cases did not correlate with the final

diagnosis. This could be because of the ultrasonographic

features, which depends on the grade of tumour. Low-grade,

small lesions can appear well-defined and similar to Pleo-

morphic adenoma. Larger lesions develop as more overtly

malignant appearance, including irregular and poorly

defined margins and heterogeneous internal architecture14

(Fig. 5).

Lipomas sonographically appeared as oval or elliptical

masses with regular margins and a typical striped or

feathered internal echotexture as per Traxler et al (1992).12

Similar findings were observed in all the four cases of

our study. Haemangioma appeared as multiple hypoechoic

areas with some amount of vascularity on Doppler study, in

our study of one case haemangioma showed similar

findings as described by the Howlett (2003)15 and Alyas et al

(2005).14

In our study benign neoplasm groupwith clinical diagnosis

had sensitivity of 71.43% and specificity of 100% where as the

sonographically 92.86% sensitivity and specificity was

observed in diagnosing benign neoplasms of head and neck.

Fig. 5 e Clear borders with Heterotrophic characteristic.

4.6. Malignant neoplasms

Out of 90 cases with head and neck swellings, four were ma-

lignant neoplasms (4.47%). All the cases reported with rapidly

growing swelling, which were diagnosed clinically as malig-

nant lesions.

The ultrasound features may depend on the grade of

tumour. Low-grade malignant neoplasms were similar to

Pleomorphic adenoma. Larger lesions develop more overtly

malignant features, including irregular and poorly defined

margins, heterogeneous internal architecture.14,15

In our study all the cases had relatively clear border 75%,

Polygonal 75% Hypoechoic 50% and Heterotrophic without

characteristics in 50%. These findings were consistent

with Howlett (2003),15 Alyas et al (2005)14 (Fig. 6).

The sensitivity and specificity of sonographic and clinical

diagnosis was 100%. Extensive studies in various literature in

evaluating soft tissue and central lesions causing head and

neck swellings have been done by several researchers. The

present study depended on the methodology used by these

researchers and evaluated the use of sonogram in diagnosing

various groups of lesions individually.

Although ultrasonographic pictures of various lesionswere

consistent and did correspond with great degree of accuracy

in all the groups of the lesions, it should only be used as an

additional diagnostic tool rather than as the only investigative

method in arriving at final diagnosis.

5. Conclusion

Ultrasonography can be used as an investigative modality for

diagnosis of head and neck swellings. Patient discomfort is

i n d i a n j o u rn a l o f d e n t i s t r y 4 ( 2 0 1 3 ) 1 2 9e1 3 6136

minimal or none in Ultrasonographic examination of head

and neck swellings. Ultrasonographic pictures do vary in

different groups of head and neck swellings, but a consistent

echo pattern can be derived as a criteria in describing the

particular group of lesions. The images that were acquired by

using 7.5e11 MHz transducer in this study did reveal quality

images and may be recommended for use in centres.

Conflicts of interest

All authors have none to declare.

r e f e r e n c e s

1. Chodosh PL, Hillside NJ, Silbey R, Oen KT, Elizabeth NJ.Diagnostic use of ultrasound in diseases of the head andneck. The Laryngoscope. 1980;90:814e820.

2. Bruneton JN. Applications of Sonography in Head and NeckPathology. 1st ed. SpringereVerlag; 2002:334.

3. Toma PL, Rossi UG. Paediatric ultrasound. II. Otherapplications. Eur Radiol. 2001;11(12):2369e2398.

4. Dewes W, Gritzmann N, Hirschner A, Koischwitz D. Highresolution small parts sonography (7.5 MHz) of the head andneck region. Radiologe. 1996;36:12e21 [in German].

5. Pogrel MA. The use of ultrasonography in diagnosis of necklumps. J Oral Maxillofac Surg. 1982;40:311e322.

6. Shimizu Mayumi, Muller J, Hartwein J, Donath KA.Comparative study of sonography and histopathologicfindings of tumorous lesions in the parotid gland. Oral SurgOral Med Oral Pathol Oral Radiol Endod. 1999;88:723e737.

7. Ishikawa H, Ishii Y, Ono T, Makimoto K, Yamamoto K,Torizuka K. Evaluation of gray-scale ultrasonography in theinvestigation of oral and neck mass lesions. J Oral MaxillofacSurg. 1983;41:775e781.

8. Siegert R. ultrasonography of inflammatory soft tissueswellings of the head and neck. J Oral Maxillofac Surg.1987;45:842e846.

9. Squire Benjamin T, F John Christian, Anderson Craig.Abscess: applied bedside sonography for convenientevaluation of superficial soft tissue infections. Acad EmergMed. 2005;12(7):601e606.

10. Partridge M, Langdon JD, Borthwick-Clarke A, Rankin S.Diagnostic techniques for parotid disease. Br J Oral MaxillofacSurg. 1986;24:311e322.

11. Yoshimura Y, Inoue Y, Odabawa T. Sonographicexamination of sialolithiasis. J Oral Maxillofac Surg. 1989Sep;47(9):907e912.

12. Traxler M, Schurawitzhi H, Ulm C, Solar P, Blahout R,Piehslinger E. sonography of non neoplastic disorders ofsalivary glands. Int J Oral Maxillofac Surg. 1992;21:360e363.

13. Van den Akker HP. Diagnostic imaging in salivary glanddisease. Oral Surg Oral Med Oral Pathol. 1988 Nov;66:625e637.

14. Alyas F, Lewis K, Williams M, et al. Diseases of thesubmandibular gland as demonstrated using high resolutionultrasound. Br J Radiol. 2005;78:362e369.

15. Howlett DC. High resolution ultrasound assessment of theparotid gland. Br J Radiol. 2003;76:271e277.

16. Yusa H, Yoshida H, Ueno E, Onizawa K, Yanagawa T.Ultrasound guided surgical drainage of face and neck abscess.Int J Oral Maxillofac Surg. 2002;31:327e329.

17. Tayal VS, Hasan N, Norton HJ, Tomaszewski CA. The effect ofsoft-tissue ultrasound on the management of cellulitis in theemergency department. Acad Emerg Med. 2006;13(4):384e388.

18. el-Silimy O, Corney C. The valie of sonography in themanagement of cystic neck lesions. J Larynngology Otology.1993;107:245e251.

19. Emshoff R, Emshoff I, Rudisch A, Bertram S. Reliability andtemporal variation of masseter muscle thicknessmeasurements utilizing ultrasonography. J Oral Rehabil.2003;30:1168e1172.

20. Morse MH, Brown EF. Ultrasonic diagnosis of Massetrichypertrophy. Dentomaxillofac Radiol. 1990;19:18e20.

21. Ariji Y, Sakuma S, Izumi M, et al. Ultrasonographic features ofthe masseter muscle in female patients withtemporomandibular disorder associated with myofascialpain. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.2004;98:337e341.

22. Yuasa K, Kawazu1 T, Nagata T, Ohishi M, Shirasuna K.Computed tomography and ultrasonography of metastaticcervical lymph nodes in oral squamous cell carcinoma.Dentomaxillofac Radiol. 2000;29:238e244.

23. Takashima S, Sone S, Nomura N, Tomiyama N, Kobayashi T,Nakamura H. Nonpalpable lymph nodes of the neck:assessment with US and US-guided fine-needle aspirationbiopsy. J Clin Ultrasound. 1997;25(6):283e292.

24. Quetz JU, Rohr S, Hoffmann P, Wustrow J, Mertens J. B-imagesonography in lymph node staging of the head and neck area.A comparison with palpation, computerized and magneticresonance tomography. HNO. 1991;39(2):61e63.

25. Atula TS, Grenman R, Varpula MJ, Kurki TJ, Klemi PJ.Palpation, ultrasound, and ultrasound-guided fine-needleaspiration cytology in the assessment of cervical lymph nodestatus in head and neck cancer patients. Head Neck.1996;18(6):545e551.

26. Sumi Misa, Ohki Masafumi, Nakamura Takashi. Comparisonof sonography and CT for differentiating benign frommalignant cervical lymph nodes in patients with squamouscell carcinoma of the head and neck. AJR.2001;176:1019e1024.