**8.2 X-ray PNS**

Water's view (Occipitomental view)/ Peer's view (Occipitomental view with open mouth) shows haziness of the involved sinus. Lateral view shows anterior bowing of posterior wall of maxillary antrum (**Holman Miller sign**).

#### **8.3 CT NOSE–PNS**

Contrast enhanced computed tomographic imaging is the investigation of choice for JNA. Infact, the diagnosis of JNA is confirmed by presence of a mass in nasopharynx and pterygopalatine fossa that enhances after contrast administration on CECT. CECT is a non-invasive procedure that forms the basis for JNA diagnosis and staging. *Lloyd's criteria for diagnosis of JNA on CECT* [32]:


*Holman Miller sign/ Antral sign:* anterior bowing of the posterior wall of maxillary antrum. This is due to the tumor mass completely filling the pterygopalatine fossa.

*Hondousa Sign:* widening of the gap between the maxillary body and ramus of mandible. This occurs when the tumor mass involves infratemporal fossa.

*Ram Haran Sign:* In JNA patients, coronal cuts of CT Nose- PNS show widening of the pterygoid wedge. It appears as a quadrilateral area rather than normal triangular area [33].

*Chopstick Sign:* CECT when used for post-operative surveillance to detect residual/ recurrent tumor, shows 'floating' medial and lateral pterygoid plates in cases where the root of pterygoid base is drilled. These pterygoid plates are visualized separately to give appearance of a pair of chopsticks.

#### **8.4 MRI**

Contrast enhanced MRI (CE-MRI) is the investigation of choice for advanced JNA tumors, particularly those with intracranial, intra-orbital, or parapharyngeal space involvement. It can accurately determine the extent of the tumor. 'Salt and pepper' appearance on contrast MRI is characteristic to any vascular tumor, resulting due to flow-void areas (T2WI and contrast enhanced T1WI) [22, 34].

*Fat Suppression MRI:* This has an immense potential in detecting bone invasion by tumor. In fat-suppression MRI sequence, a normal pterygoid wedge should be hypointense owing to fat-rich marrow. Any iso/hyper-intensity in that area indicates invasion by the tumor, therefore, requiring bone drilling to avoid recurrence.

MRI is also the preferred modality for post-operative long-term surveillance because of its superior soft tissue differentiation quality without any radiation exposure.

#### **8.5 CT-angiography**

CT angiography is useful to identify the feeder vessel(s) to the tumor. Internal maxillary artery is the most common feeder vessel for JNA. JNA may additionally acquire blood supply from ascending pharyngeal artery, contralateral external carotid artery branches, ipsilateral or contralateral internal carotid artery and its branches (ophthalmic, meningohypophyseal, vidian artery).

Knowledge about the feeding vessel and its site of entry into the tumor is absolutely critical to decide the surgical approach for JNA excision. For example, where feeder vessels are located posterior to the main tumor mass without direct access, open approach is preferred to endoscopic approach.
