CT Scan and MRI study

👶 1. The "6 mm" Rule (Top-Left Panel)
👥 Demographic: Infants and children

📏 Maximum Normal Height: 6 mm

📐 Upper Surface Shape: Flat or concave upper surface (indicated by a straight white line resting over a shallow gland).

🧑 2. The "8 mm" Rule (Top-Right Panel)
👥 Demographic: Postmenopausal Female (♀) & Adult Male (♂)

📏 Maximum Normal Height: 8 mm

📐 Upper Surface Shape: Flat or concave upper surface (indicated by a slightly dipping, curved white line).

👩 3. The "10 mm" Rule (Bottom-Left Panel)
👥 Demographic: Females of "childbearing age" (♀)

📏 Maximum Normal Height: 10 mm

📐 Upper Surface Shape: Convex upper surface (indicated by an upward-curving dome line, reflecting normal hormonal hypertrophy).

🤰 4. The "12 mm" Rule (Bottom-Right Panel)
👥 Demographic: Females in late pregnancy + postpartum period (♀)

📏 Maximum Normal Height: 12 mm

📐 Upper Surface Shape: Convex upper surface (indicated by a highly elevated, asymmetric dome line, reflecting peak physiological enlargement).

🧠 1. Metastasis (Top-Left Panel)
🟡 Imaging Appearance: Shows a large, well-defined mass within the cerebellar hemisphere with peripheral ring enhancement and surrounding swelling.

📝 Key Notes: Text reads: "Adults; Can look like anything"

🩸 2. Hemangioblastoma (Top-Middle Panel)
🔵 Imaging Appearance: Shows a highly vascular, bright solid nodule sitting adjacent to a large, dark fluid-filled cyst cavity.

📝 Key Notes: Text reads: "Adults; Nodule+Cyst"

🌸 3. Pilocytic astrocytoma (Top-Right Panel)
🟢 Imaging Appearance: Similar to hemangioblastoma, it classically presents as a large, dark cystic lesion with a highly enhancing bright mural nodule along its wall.

📝 Key Notes: Text reads: "Children; Nodule+Cyst"

🐯 4. L’Hermitte-Duclos (Bottom-Left Panel)
🟤 Imaging Appearance: Shows an ill-defined thickening of the cerebellar folia with alternating bright and dark bands creating a striated look.

📝 Key Notes: Text reads: "Any age; tigroid pattern" (also known as dysplastic cerebellar gangliocytoma).

❌ 5. Medulloblastoma (Bottom-Middle Panel)
🔴 Imaging Appearance: Displayed on a Diffusion-Weighted Imaging (DWI) MRI scan as a very bright white mass, indicating highly cellular pathology.

📝 Key Notes: Text reads: "Children > adults; diffusion restriction"

📊 Summary Box: Most Frequent Cerebellar Tumor In (Bottom-Right Panel)
The guide provides a quick diagnostic rule of thumb based on patient age:

👴 (Older) adults: metastasis
🧑 (Young to middle aged) adults: hemangioblastoma
👶 Children: pilocytic astrocytoma

🧠 1. Pineal Gland (Top-Left)
🔴 Details: Shows a comparison between an initial scan (1st MRI) where the lesion is extremely tiny or unnoticeable, and a follow-up scan (FU) showing a clear, bright metastatic nodule.

🔬 Significance: Normal physiological calcification or cysts can mask early metastatic growths in this midline structure.

🧠 2. Pituitary (Top-Right)
🟡 Details: Features a sagittal MRI profile with a magnified inset box focused tightly on an enlarged, enhancing skull base region labeled Pituitary.

🔬 Significance: Tumors tracking to the pituitary gland or pituitary stalk can mimic primary adenomas or get lost in complex sellar anatomy.

🧠 3. Choroid plexus (Middle-Left)
🔵 Details: Shows an axial MRI brain scan highlighting a bright, well-defined mass tracked inside a dashed white square box within the lateral ventricle.

🔬 Significance: Because the choroid plexus normally enhances brightly with contrast, a true vascular tumor seedling can easily blend into the normal background.

🧠 4. Spinal Cord (Middle Center)
🟠 Details: Uses a sagittal head-neck view with an orange arrow tracking over to a close-up section, exposing a small, bright metastatic dot inside the upper cervical canal path.

🔬 Significance: Brain MRI protocols often cut off right at the top of the neck, completely missing lesions lurking slightly lower down the cord.

🦴 5. Clivus & Skull (Middle-Right)
🟢 Details: A sagittal view focused on the bone boundaries with two distinct green arrows pointing out the Clivus (anterior skull base) and the Skull occipital bone region.

🔬 Significance: Lesions confined purely to the marrow of the skull base or calvarium can be missed if the reviewer is focusing exclusively on the soft brain tissue.

👁️ 6. Cranial nerves & Orbits (Bottom Row)
🟢 Cranial nerves (Bottom-Left): Zoomed-in axial image pointing out fine pathways with labels for Meckel cave and n. VIII (Vestibulocochlear nerve). It shows how leptomeningeal disease can coat tiny nerve roots unnoticed.

⚪ Orbits (Bottom-Right): Displays multiple specialized axial eye tracks with white and gray arrows pointing out focal metastatic lesions resting directly inside the globes or extraocular spaces.

🧠 Lateral Temporal Gyri (Left Side)

🔴 Superior temporal gyrus: Highlighted in red at the upper outer portion of the temporal lobe.

➡️ Heschl Gyrus: An arrow points specifically to the upper-back portion of this red region, marking the primary auditory cortex.

🔵 Middle temporal gyrus: Highlighted in blue, located directly beneath the superior temporal gyrus.

🟣 Inferior temporal gyrus: Highlighted in purple at the bottom-left outer edge of the lobe.

🧠 Medial & Ventral Temporal Structures (Right Side)
🟡 Lateral temporo-occipital gyrus: Highlighted in yellow/tan along the lower surface of the brain, transitioning toward the occipital lobe.

🟢 Parahippocampal gyrus: Highlighted in green, located medially next to the lateral temporo-occipital gyrus.

🟤 Hippocampus: Highlighted in brown/orange and marked with an arrow, sitting deeply inside the medial temporal lobe directly above the parahippocampal gyrus.

🟢 1. Normal Anatomy (Top-Left Panel)🧠 Anatomy Outlined: Shows a fully formed, healthy corpus callosum and surrounding structures with specific labels:

Genu, Truncus, Isthmus, Splenium, and Rostrum (the different segments of the corpus callosum).

Anterior commissure, Septum pellucidum, Fornix, and Thalamus / Thalamic adhesion.An arrow points out a "Normal isthmal notch"

🟤 2. Complete Callosal Agenesis (Top-Right Panel)🚫 Phenomenon: The corpus callosum is completely missing.🔬 Key Features: The scan shows an empty space where the bundle of nerves should be, along with a label pointing to a "Tiny anterior commissure?".

🟠 3. Partial Callosal Agenesis (Second Row Panels)

📐 Left Scan ("Some truncus"): Shows a partially formed structure labeled with "Some truncus" and "Splenium", an "Anterior commissure", and a "Commissural plate remnant".

📐 Right Scan ("Hypertrophic"): Points out an "Anterior commissure" and a "Commissural plate remnant" leading up to a "'Hypertrophic' hippocampal commissure (≈ rudimentary splenium)".

🟢 4. Hippocampal Commissure Agenesis vs. Blunt Splenium (Third Row Panels)

📉 Hippocampal commissure agenesis (Left Scan): Features "Low hanging fornices" and notes "No hippocampal commissure $\rightarrow$ no development of splenium" within a circled area.

📉 Callosal hypoplasia, "blunt" splenium (Right Scan): Shows "Normal position fornices" and a circled area noting "Hippocampal commissure present, blunt splenium".

🟡 5. Callosal Hypoplasia & Dysplasia (Bottom Row Panels)

📉 Callosal hypoplasia (minor dysplasia) [Left Scan]: The corpus callosum is formed but thinner than usual. The text notes: "All components present, minor morphological irregularities".

📉 Callosal hypoplasia with dysplasia (Right Scan): The structure is both underdeveloped and malformed. The text notes: "Small corpus callosum, abnormal morphology".

🧠 Anatomical Structures Involved (Top Panel)

The graphic uses a vertical red shading overlay on the diagram (matching the white area of the stroke on the MRI scan) to show an injury to three specific pathways:

1. Corticospinal tract

2. Medial Lemniscus

3. Hypoglossal nucleus

♿ 1. Contralateral hemiparesis leg & arm
💪 Clinical Presentation: Weakness or paralysis affecting the leg and arm on the opposite (contralateral) side of the body.

🚫 Facial Sparing: The face is spared. This is because motor innervation to the face is handled by the corticobulbar tract and cranial nerves V and VII located higher up in the pons.

🔬 Anatomical Cause: Infarction of the corticospinal tract (labeled as 1. in the upper maroon segment).

🪵 2. Contralateral hemisensory loss
🧠 Clinical Presentation: Loss of specific sensory modalities on the opposite side of the body, explicitly involving vibration, proprioception & fine touch.

🚫 Facial Sparing: The face is spared in this sensory loss as well.

🔬 Anatomical Cause: Infarction of the Medial Lemniscus pathway (labeled as 2. in the central shaded segment).

👅 3. Ipsilateral hypoglossal palsy
👅 Clinical Presentation: Weakness or paralysis of the tongue on the same side (ipsilateral) as the stroke lesion, causing it to typically deviate toward the side of injury.

🔬 Anatomical Cause: Infarction of the Hypoglossal nucleus (labeled as 3. near the back center of the medullary cross-section).

Name of the lesion???

MRI Prostate Cancer and anatomy

🧠 Anatomical Structures Involved (Top Panel)
The graphic overlays a bright white patch on the right side of the brainstem MRI (left side of the image) to match the red lesion zone in the anatomical drawing. This lesion impacts two critical structures:

1. Corticospinal & -bulbar tract

2. Oculomotor fascicles

♿ 1. Contralateral hemiparesis
💪 Clinical Presentation: Weakness or paralysis of the contralateral (opposite side) face, arm, and leg.

🔬 Anatomical Cause: Infarction of the corticospinal & -bulbar fibers located within the cerebral peduncle (highlighted as the red area labeled 1. on the purple structure).

👁️ 2. Ipsilateral oculomotor palsy
👁️ Clinical Presentation: The affected eye turns "down & out", experiences ptosis (drooping eyelid), and has a non-reactive pupil in mydriasis (permanently dilated pupil).

🔬 Anatomical Cause: Infarction of the oculomotor fibers near the interpeduncular cistern (indicated by the brown arrow pathway labeled 2. passing directly through the lesion zone).

MRA of Cerebral artery Anatomy