The anatomic basis for ultrasound in the diagnosis and treatment of styloid process-related diseases

General Research Papers
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For those that suspect Eagle Syndrome and do not want the radiation from CT or do not have access to CT Scan, can easily be diagnosed with ultrasound based on this study. Size of the Styloid and its interaction with major vessels of the neck can easily be obtained from doppler ultrasound much like the CT but the bonus is, blood flow can also be assessed with Ultrasound. A good alternative for folks seeking diagnoses in remote locations where CT is not easily available.

One caveat is the technologist doing the ultrasound needs to have good grasp of the area I think as the ultrasound is highly dependent on the expertise of the technologist.

Abstract

Background

The styloid process (SP), stylohyoid ligament and lesser horn of hyoid bone together form the stylohyoid chain. Differences in the ossification degree and the connection sites of each segment of the stylohyoid chain on both sides lead to variations in the length, orientation, thickness, and straightness of SP. The incidence of elongation of the SP, known as styloid process syndrome (SPS), is around 4%, with only 4% of patients showing elongation show symptoms. Computed tomography (CT) remains the first-choice auxiliary examination for diagnosing SPS, but its performance can be affected by a variety of factors. Ultrasound can reveal the parapharyngeal space and adjacent structures, which offer high consistency with CT findings. Here, we investigated the ultrasonographic features of the SP and its adjacent structures in normal adults and assessed the clinical utility of ultrasound assessment for SP-related diseases.

Methods

With the ramus of mandible, mastoid process, SP, and salivary gland as the anatomical landmarks, ultrasonography was conducted on the parapharyngeal space in 78 healthy adults. The scans were performed along the oblique coronal section of the ramus and the cross-sectional plane between the mastoid process and ramus to visualize the SP and its adjacent structures. The SP length, the shortest distance from the SP tip to the outer edge of tonsil (SP-tonsil distance), and the distance from SP to the internal carotid artery (SP-ICA distance) were measured.

Results

SP and its adjacent structures were successfully visualized on ultrasonography in all 78 subjects. The measured SP length was 2.65±0.48 cm. The SP-tonsil distance was 1.95±0.50 cm. The SP-ICA distance was 0.509±0.231 cm. The SP length and SP-tonsil distance measured by ultrasound were not significantly different from those measured by CT (P=0.071, P=0.053). Furthermore, the SP length and SP-tonsil distance measured by ultrasound were positively correlated with CT measurements (r=0.917, P=0.071; r=0.978, P=0.053, respectively). SP-tonsil distance was negatively correlated with SP length and SP inward deflection angle.

Conclusions

Ultrasound can accurately reveal the shape and size of SP and its adjacent structures and thus will be helpful for the diagnosis of SP-related diseases.

Ultrasound can also show Styloid impingement/compression on major Veins & Arteries of the Neck

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Almost identical measurement of CT can be obtained from Ultrasound as table below from the study shows.

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Study link : Europe PMC

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It would be cool if there was a list of radiologists that knew how to do this because most I spoke to and seen are not familiar with measuring IJV flow with ultrasound.

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Anyone with doppler US training should technically know as they measure blood flow of the Carotid all the time but you are right IJV needs additional care and also the bony structure at the skull base might make it difficulty to accurate measure the sound wave reflection from the blood so angle of the probe and proper placement of it needs to be accurate as the result can wildly vary if not done with care. Sound travels at different speeds between Bone vs Body tissues so measurements could be skewed.

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