CT Angiography and Its Correlation in ENT Practice

1. Principles of CTA Relevant to ENT

"In CT angiography, the continuous acquisition of images allows following the rapidly injected intravenous bolus of contrast through the arteries and veins of the areas under investigation. The reconstructed images can be rotated in the plane that best demonstrates the vessels."

• Shambaugh Surgery of the Ear

2. Neck Trauma

2a. Penetrating Neck Injuries

• Multislice helical CTA is a sensitive, noninvasive diagnostic screening test that evaluates both the vascular structures and the aerodigestive structures of the neck simultaneously.
• One study of multislice helical CTA in 91 penetrating neck injuries reported high sensitivity and specificity.
• For Zone I and Zone III injuries in stable patients, arteriography (increasingly CTA) is typically required. Zone II injuries may or may not need vascular imaging depending on clinical signs.
• Indications for vascular imaging after penetrating trauma include: persistent hemorrhage, expanding hematoma, neurologic deficits, Horner syndrome (suggesting sympathetic plexus injury/carotid sheath violation), hoarseness (recurrent laryngeal nerve), and suspected carotid or vertebral injury.

"In stable patients with nonemergent injuries, multislice helical CT angiography can be a useful diagnostic screening test to noninvasively assess cervical vascular structures."

• Cummings Otolaryngology Head and Neck Surgery

2b. Blunt Neck Trauma

• CTA with multiplanar and 3D reconstruction is particularly valuable here because clinical signs are often absent or delayed.
• Specifically, CTA assists in evaluation of carotid artery dissection, vertebral artery injury, and pseudoaneurysm in blunt trauma settings.
• Treatment decisions (surgery, anticoagulation, or observation) are guided by CTA findings including mechanism, type, and location of injury.

"CT angiography is very useful in the diagnosis of arterial injuries in the neck. Specifically, CT angiography using multiplanar and three-dimensional reconstruction capabilities has been described to assist in the evaluation of blunt neck trauma injuries."

• Cummings Otolaryngology Head and Neck Surgery

3. Temporal Bone and Otology

3a. Temporal Bone Fractures and Carotid Canal Injury

• A fracture through the carotid canal on HRCT carries an ~18% incidence of carotid artery injury (vs. ~5% when the canal is spared).
• In asymptomatic patients with carotid canal fractures, angiography yields little additional clinical utility.
• However, if transient or persistent neurologic deficits are present in basilar skull fractures, HRCT of the temporal bone plus CTA is indicated.

3b. Pulsatile Tinnitus

• For jugular bulb and sigmoid sinus anomalies, CTA/V of the temporal bone is recommended as the initial imaging study.
• For dural arteriovenous malformations (dAVM/F), CTA/V is useful but small lesions can be missed - formal four-vessel angiography may then be required.

4. Paragangliomas (Glomus Tumors) of the Temporal Bone and Neck

• CT (bone windows) remains the cornerstone - showing characteristic irregular destruction of the jugular foramen (vs. smooth enlargement in schwannomas).
• MRI provides complementary soft-tissue information (classic "salt-and-pepper" pattern, flow voids).
• Angiography (conventional or CTA) delineates the vascular pattern, which is characteristic for paragangliomas, and is a necessary step in preoperative embolization.
• Critically: CTA and MRA have NOT replaced direct intravascular angiography for glomus tumor management. Conventional angiography remains the gold standard for preoperative embolization planning.
• For skull base neoplasms requiring carotid artery manipulation: temporary balloon occlusion + xenon CT (or radioisotope imaging) is used to assess adequacy of collateral blood flow via the circle of Willis before carotid sacrifice is considered.

"Angiography is a necessary step in preoperative embolization of glomus tumors; in fact MRA, magnetic resonance angiography, and CT angiography (CTA) has not replaced direct intravascular angiography in glomus tumor management."

• Cummings Otolaryngology Head and Neck Surgery

5. Head and Neck Cancer - Preoperative Planning and Reconstruction

5a. Carotid Artery Involvement

• MRA, CTA, Doppler ultrasonography, or conventional angiography can be used preoperatively to assess:
  • Carotid artery encasement or invasion (limits resectability)
  • Adequacy of external carotid branches to support microvascular anastomosis
  • Patency of the transverse cervical artery as a recipient vessel
  • Status of jugular venous network (predicting need for sacrifice)

5b. Microvascular Free Flap Reconstruction

• Fibular free flap: The most commonly used flap for mandibular reconstruction. Preoperative CTA (or MRA/Doppler) of the lower extremities confirms three-vessel runoff and ensures the foot is not dependent on the peroneal artery alone before harvesting the fibula.
• Anterolateral thigh (ALT) flap: CTA or Doppler used to locate and map perforating vessels pre-harvest.
• Other flaps (radial forearm, scapula, iliac crest): Angiographic studies including CTA help detect anatomic vascular anomalies, confirm adequate perforator supply, and document adequacy of distal collateral perfusion.

"CT angiography, angiography, and color Doppler studies can also be utilized, based on surgeon preference" for fibular free flap preoperative planning.

• Cummings Otolaryngology Head and Neck Surgery

6. Vertebral Artery Dissection and Stroke Syndromes

• Vertebral artery dissection - especially in the setting of significant ongoing neck pain after trauma
• Carotid artery dissection - associated with Horner syndrome (ptosis, miosis, anhidrosis)
• These presentations may present to ENT/audiovestibular clinics before a neurologic diagnosis is established

7. Comparison with Other Imaging Modalities in ENT

8. Specific Clinical Indications Summary

Recent Evidence

Key Takeaways

1. CTA is the workhorse noninvasive vascular imaging tool in ENT - replacing conventional angiography for screening in most trauma and tumor settings.
2. Conventional (DSA) angiography retains superiority where therapeutic intervention (embolization) is planned, especially for paragangliomas and dAVF.
3. CTA/CTV of the temporal bone is the first-line study for jugular bulb and sigmoid sinus anomalies causing pulsatile tinnitus.
4. In free flap reconstruction, CTA confirms donor-site vascular anatomy and prevents catastrophic harvest complications.
5. Combined CT + MRI + CTA provides the most complete picture for skull base and parapharyngeal space lesions.
6. The simultaneous extravascular detail (bone, airway, soft tissue) is a unique advantage of CTA in ENT - unavailable with conventional angiography.

Otitic Hydrocephalus

Definition and Terminology

• Increased intracranial pressure (ICP)
• Normal CSF biochemistry and cell count
• No space-occupying lesion or obstruction to CSF flow
• No ventricular dilatation
• Spontaneous recovery tendency

"Otitic hydrocephalus is a rare complication of otitis media and stems from either AOM or COM... has a favorable prognosis and is very commonly associated with sigmoid sinus thrombophlebitis."

• Shambaugh Surgery of the Ear

Otologic Source

• Acute otitis media (AOM) - particularly in children
• Chronic otitis media (COM) - with or without cholesteatoma
• Rarely, otologic surgery

Pathophysiology

The Cascade:

1. Otitis media / mastoiditis → septic thrombophlebitis of the sigmoid sinus
2. Retrograde propagation to the transverse sinus, inferior petrosal sinus, cavernous sinus, and ultimately the superior sagittal sinus
3. Thrombosis of the superior sagittal sinus → blockage of arachnoid granulations (villi)
4. Impaired CSF reabsorption → raised intracranial pressure
5. No obstruction to CSF circulation → ventricles remain normal in size

Alternative Theories:

• Sahs and Joynt: Brain edema from interstitial mechanisms (brain biopsies show interstitial edema, yet EEG and neurologic function remain normal)
• Weed and Flexner: Disruption of venous circulation causes direct rise in CSF pressure (CSF pressure is directly related to intracranial venous pressure)
• Increased CSF volume theory (separate from absorption impairment)

Determinants of Symptom Development After Lateral Sinus Occlusion (Cummings):

1. Relative size of the involved lateral sinus vs. the contralateral side
2. Adequacy of the collateral venous network (cavernous sinus, opposite inferior petrosal sinus)
3. Likelihood of thrombosis propagating to additional venous outflow channels

Classification - Context Within Intracranial Complications of Otitis

• Extradural abscess

• Leptomeningitis / Meningitis
• Pachymeningitis / Subdural abscess
• Brain abscess
• Otitic hydrocephalus

• Lateral (sigmoid) sinus thrombophlebitis - most commonly associated with otitic hydrocephalus

Clinical Features

The Classic Triad:

Progression:

• In uncomplicated cases with medical management: headache ameliorates over 3-7 days
• If collateral venous drainage is inadequate: dulling of sensorium, decreased visual acuity from retinal vein occlusion
• Progression to coma and death is possible in severe untreated cases
• Optic atrophy can develop from chronic papilledema - representing a major cause of permanent morbidity

Investigations

1. CT Scan (with IV contrast)

• First investigation in practice - rules out brain abscess, subdural empyema, and other space-occupying lesions
• May show sigmoid/transverse sinus thrombosis as a filling defect ("empty delta sign" on post-contrast CT)
• Ventricles are normal or small - distinguishing it from true hydrocephalus
• CT of mastoids reveals the underlying otologic disease

2. MRI / MR Venography (MRV)

• Modality of choice for definitive assessment - superior evaluation of venous sinuses
• MRV confirms dural sinus thrombosis (sigmoid, transverse, superior sagittal sinus)
• Note: MRV confirms but is not required for the diagnosis of otitic hydrocephalus
• Important to rule out co-existing brain abscess, meningitis, subdural empyema

3. Lumbar Puncture (LP)

• Shows raised CSF opening pressure (often >25 cmH₂O)
• Normal CSF biochemistry: normal glucose, protein, and cell count
• This combination (raised pressure + normal CSF analysis) is the classic finding
• Caution: LP must be performed carefully given risk of cerebellar tonsillar herniation; a CT must be done first to confirm absence of mass lesion

Summary of Typical Findings:

Management

I. Treatment of Ear Disease

II. Reduction of Raised ICP (Medical)

III. Surgical / Procedural Options

Role of Anticoagulation

• Consider anticoagulation in cases of superior sagittal sinus thrombosis
• Role in sigmoid sinus thrombosis is debated; more recent case series support mastoidectomy + antibiotics without mandatory sinus opening

Prognosis

• Overall favorable prognosis compared to other intracranial complications of otitis
• Most cases resolve with treatment of underlying ear disease and medical ICP management
• Primary morbidity is visual loss from progressive papilledema leading to optic atrophy
• A recent 2025 retrospective study (PMID: 39562726) at a quaternary children's hospital found:
  • 93% of 15 patients developed papilledema
  • 40% had CN VI palsy
  • 73% had progressively worsening papilledema despite improving infection and clot burden
  • Systemic corticosteroids significantly improved visual outcomes and helped avoid invasive neurosurgical procedures
  • Two patients developed optic atrophy and visual loss before corticosteroids were started - both stabilized after initiation

Key Points to Remember

1. Otitic hydrocephalus = raised ICP + normal CSF + no ventricular dilatation - in the setting of ear disease.
2. Most commonly follows sigmoid sinus thrombophlebitis from AOM or COM.
3. The pathophysiology is blockage of arachnoid villi from retrograde dural sinus thrombosis, impairing CSF reabsorption.
4. Classic triad: otitis media + papilledema + VI nerve palsy.
5. MRI/MRV is the imaging modality of choice; LP confirms raised pressure with normal CSF.
6. Treatment = ear surgery (mastoidectomy) + medical ICP reduction (acetazolamide, mannitol, steroids).
7. Optic atrophy is the main long-term morbidity - serial ophthalmologic examination is mandatory.
8. Despite the name, it is not true hydrocephalus - ventricles are normal or small.
9. It is more accurately called benign intracranial hypertension (pseudotumor cerebri) secondary to otologic disease.