Friday, August 30, 2019

What does 'non-specific shallow cortical hyper density in left post-central gyrus' mean?


Cortical means pertaining to the outer layer or rind of the cerebrum, the cerebral cortex. This is where most of the neuron cell bodies are—the centres of thought, sensation, memory, muscle control, speech, etc. It’s the “gray matter” of the brain (most of it, anyway).
Gyrus means one of the raised folds of the cerebral cortex, the wrinkles of the brain.
Post-central refers to one of the grooves between these gyri, called sulci. I’ve marked a few gyri and sulci on the textbook photo below.
One of these is called the central sulcus. It descends from the top of the brain toward the ear and separates the frontal lobe of the brain (centre of thought, memory, judgment, emotion, etc.) from the parietal lobe.
Post central gyrus means the first gyrus behind that central sulcus. I’ve circled the labels on this textbook photo and marked that gyrus with a row of asterisks.



This gyrus is where “general” sensory signals from the body arrive (not for vision, hearing, or other “special senses”). It serves such senses as touch, pain, heat, cold, pressure, itch, tickle, stretch, etc. Sensory signals from the lowest points on the body arrive in the uppermost part of the gyrus and down in the deep groove between the right and left cerebral hemispheres. The lowest part of the gyrus receives sensory input from the face. The diagram below shows the origins of the signals that arrive at different levels of that gyrus.

Hyper density means that the image you’re referring to (a CT scan?) shows a region of brain tissue a little more dense than usual. Here is a cerebral CT scan with an arrow indicating a hyper dense region in this patient. This particular patient was a 48-year-old man experiencing atypical headaches and left-sided muscle weakness after receiving a neck injury in a hockey game.

Putting it all together, your description means that there is a hyper dense region of cerebral cortex, not far below the brain surface, in the left post central (sensory) gyrus. I’m not a physician and can’t guess at a diagnosis (even a physician couldn’t diagnose anything from this limited information), but I think the nonspecific part of this just means that the hyper density seen in that image doesn’t point to any specific diagnostic conclusion. It might not be anything to be concerned about, or it might result in some sensory effects depending on which part of that gyrus is affected.

Reference: Ken Saladin

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