Strategies to Avoid Diagnostic Pitfalls in Head and Neck Imaging
Radiology interpretation of head and neck imaging is prone to error.
The interpretation of head and neck imaging is particularly prone to error. This is due to its inherently complex anatomical landmarks, certain physiological variants, and varied pathology. Nevertheless, it is important that the radiologist recognize what is a normal finding (as anatomical variants) and be aware of some pathologies that should not be missed.
Normal findings in head and neck imaging that should be known:
- Report of surgically risky anatomic variants is crucial in the planning of functional endoscopic sinus or other skull base surgery because its presence might influence the surgical approach. Look for sphenoethmoidal (Onodi) cells, infraorbital ethmoidal (Haller) cells, dehiscence of the lamina papyracea, asymmetry of the ethmoid roof, protrusion of the internal carotid artery into the sphenoid sinus, aberrant internal carotid artery in the temporal bone, dehiscence of the tympanic segment of the facial nerve, and persistent stapedial artery as risky anatomic variants.
- Retropharyngeal lymph nodes should be considered normal in children and must not be interpreted as a pathological finding (not so in adults).
- A blood-contrast level in the internal jugular vein is normal due to physiological flow during contrast-enhanced CT. It has no pathological significance and does not need further examinations.
- Recognizing the normal appearance of the cervical portion of the thoracic duct is important to differentiate it from pathologic lesions of the lower neck.
- Don’t forget that parathyroid glands exist. They might be cystic or ectopic, and might be located anywhere in their path of migration from the hyoid bone to the carina, or even inside the thyroid gland.
Pathologies in head and neck that should not be missed:
- Not all cystic masses of neck are second branchial cleft cysts! In a middle-aged or elderly patient with a new neck mass, a diagnosis of head and neck squamous cell carcinoma must be considered before dismissing the mass as a congenital lesion (due to a necrotic node metastases). Furthermore, a primary tumor in the tonsil or the base of tongue might be small. Unless the radiologist suspects the diagnosis, it can be easily overlooked.
- Nasopharyngeal cancer should be suspected in every adult who presents with an isolated otitis media with effusion.
- In patients with head and neck oncological history, look for perineural spread. Imaging plays a critical role because this condition might be asymptomatic and carries a grave prognosis. Furthermore, it is one of the most frequent missed diagnoses in head and neck imaging.
- If problems persist after corrective treatment in head and neck cancers, look for adenopathies in anatomic blind spots such as retropharyngeal and retropectoral areas.
- Papillary carcinoma should be considered in all thyroglossal duct cysts that have a mural nodule, or internal calcifications, or both.
- In all tonsillar abscesses with affectation of the retropharyngeal space, it is mandatory to include the mediastinum due to the potential possibility of infection spread from the cervical spaces to the mediastinum through the “danger space”.
- In the presence of otomastoiditis, look for its complications such as cerebellar abscess and venous thrombosis, especially in children.
- In the presence of sinusitis, look for its origin such as odontogenic or invasive fungal.
- Remember that medication-related osteonecrosis of the jaw exists and should not be confused with a neoplastic process.
- In patients with chronic neck pain, look for rare causes such as calcification of the transverse ligament of the atlas or periodontoid pseudotumor.
- Remember to evaluate head and neck principal muscle groups. Findings might be surprising. Look for discontinuities, agenesis, supernumerary muscles, hypertrophy, and denervation.
- And last but not least, look for intrathoracic goiters and possible tracheal compression. This step might be basic, but it is frequently overlooked and it really matters to the patient and surgeon.
Read the authors’ blog on 15 strategies to help minimize radiological errors in MRI, CT, and ultrasound imaging.
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Paola A. Barón Ródiz, M.D. is a Radiology Resident at Hospital Universitario Severo Ochoa in Leganés, Madrid – Spain
Concepción Ferreiro Argüelles, M.D. is a Neuroradiologist at Hospital Universitario Severo Ochoa in Leganés, Madrid – Spain