New Video on Radiant Pixels: Intracanalicular Vestibular Schwannoma & The "Monkey Face" Mnemonic

-

 


Welcome back to the blog. Following up on my previous posts, Monkey looking at cerebellum and Small  Vestibular Schwannoma, I have just published a new companion video on the Radiant Pixels YouTube channel that brings these concepts to life.

If you are looking to sharpen your diagnostic skills regarding internal acoustic canal pathology and anatomy, this case presentation is for you.

What to Expect in the New Video

In this latest upload, I walk through a classic presentation of a 75-year-old patient experiencing left-sided hearing loss. We review the imaging step-by-step, starting with the thin-slice T2 sequences that are highly sensitive for evaluating the internal acoustic canals, all the way through to the contrast-enhanced T1 coronal slices.

Key highlights of the case include:

  • Identifying a normal vascular AICA-loop at the level of the porus acusticus and understanding when to note it for the clinician.

  • Locating and measuring a small 5 mm by 3 mm dark structure plugged directly in the left internal acoustic canal.

  • Analyzing the contrast enhancement that confirms the diagnosis of an Intracanalicular Vestibular Schwannoma.

Mastering the Anatomy: The "Monkey Face" Mnemonic

One of the most challenging aspects of evaluating these scans is quickly identifying the complex nerve anatomy within the internal acoustic canal. In the video, I share one of my favorite visual mnemonics using the sagittal slice.

When you look at a transverse cut to the axis of a normal internal acoustic canal, the structures often resemble the face of a monkey:

  • The V-Shaped Mouth: The vestibular nerve.

  • The Right Eye: The cochlear nerve.

  • The Left Eye: The facial nerve.

To never mix up the "eyes," I explain how to apply the "Seven Up" (7UP) rule, reminding us that the facial nerve (cranial nerve VII) is always the upper dot.

Watch the Full Case

Seeing the slices dynamically scroll on the screen is the best way to train your eye to spot these sometimes easily missed 2–3 mm tumors.

If you find this type of radiological case presentations helpful for your studies or daily practice, please consider subscribing to Radiant Pixels so you never miss a new case. Stick around until the very end of the video for a custom ambient outro track, The June 5th Protocol, to close out the session.

Thank you for reading and watching!

Popular posts from this blog

Broca's Infarct

-
Image
Patient presented with expressive dysphasia . MRI shows acute infarct in Broca's Area in the left inferior frontal gyrus that is responsible for speech production. Note high signal on DWI, low on corresponding ADC as well as signal changes on T2 and coronal FLAIR.
Read more

Hemorrhagic Choroid Plexus Cyst

-
Image
Transversal Diffusion Weighted sequence shows high signal in the left choroid plexus with corresponding low signal on ADC (restricted diffusion). Finding represents acute Hemorrhagic Choroid Plexus Cyst . It is also known as Choroid Plexus Xanthogranuloma . Gradient Echo sequence (third image) shows low signal in the right choroid plexus representing hemosiderine deposits after previous hemorrhage. Coronal T1 shows intermediate to high signal in the plexus cyst. Note also low signal in the right plexus on T2 (old hemorrhage) and high signal on FLAIR in the left plexus (acute hemorrhage). Choroid Plexus Cysts are very common normal finding. Those often show restricted diffusion. However in our case of patient with hypertension this finding is of interest to the clinicians as a requirement to more closely monitor patient's blood pressure. There were no signs of intraventricular hemorrhage.
Read more

Huntington Disease

-
Image
10 years old boy from parents being cousins to each other presents with progressive rigidity and dystonia. Initial MR showing significant bilateral atrophy in caudate nuclei and putamina with high signal on FLAIR and T2 consistent with gliosis. Note striking symmetric atrophy of the putamina and caudate nuclei on T2 and IR. Huntington disease (HD) is also known as Huntington chorea. HD is an autosomal dominant chronic hereditary neurodegenerative disorder with complete penetrance [Osborn].  Aggregates of huntingtin protein accumulate in axonal terminals, which eventually leads to the death of medium spiny neurons. Autopsy shows generalized cerebral atrophy with an average of 30% reduction in brain weight. Both the cortex and hemispheric WM are affected. The most characteristic gross abnormality is volume loss with rarefaction of the caudate nucleus, putamen, and globus pallidus [Osborn].  Microscopically, HD features neuronal loss with huntingtin nuclear inclusi...
Read more