# June 2025

- Link: https://isnr.in/june-2025/
- Published: 2025-06-11T14:41:36+05:30
- Author: ISNR

## June 2025

## CASE HISTORY

20 year old male patient presented with headache for 2 days, altered sensorium and
single episode of seizure. He had a major road traffic accident one week back.

## CASE CONTRIBUTED BY

Dr. **Charu Paruthi**^(1), Dr. **Reeta Kanaujiya**^(1)
^(1)ProfessorDepartment of
Radiodiagnosis and IR, VMMC and Safdarjung Hospital, New Delhi

![](https://isnr.in/wp-content/uploads/2025/06/case-of-the-month-june-2025-1024x627.
jpg)

![](https://isnr.in/wp-content/uploads/2025/06/case-of-the-month-june-2025-1-1024x352.
jpg)

![](https://isnr.in/wp-content/uploads/2025/06/case-of-the-month-june-2025-figure-
1-1024x630.jpg)

(a-c) FLAIR images show multiple small ill-defined confluent white matter hyperintensities
involving bilateral frontal periventricular regions and bilateral centrum semiovale(
internal watershed areas), bilateral cerebellar white matter. Roght middle cerebellar
peduncle, posterior limb of internal capsule, thalami and splenium of corpus callosum.(
d-g) Small punctate areas of diffusion restriction are seen in bilateral basal ganglia.
Patchy diffusion restriction is seen in bilateral centrum semiovale.

![](https://isnr.in/wp-content/uploads/2025/06/case-of-the-month-june-2025-figure-
2-1024x352.jpg)

(h-j) SWI images (magnitude) show multile microbleeds diffusely scattered in the
involved regions (cerebellar white matter, middle cerebellar peduncles, periventricular
white matter and centrum semiovale): **WALNUT KERNEL PATTERN**. These are more in
the central white matter than at gray-white matter junction.

![](https://isnr.in/wp-content/uploads/2025/06/case-of-the-month-june-2025-figure-
3-300x277.jpg)

X-ray pelvis with both legs shows fracture of the neck of femur on the right side.

## Diagnosis: Cerebral Fat Microembolism

 * Cerebral Fat embolism usually occurs secondary to fracture of long bone and may
   be: Macroembolism (similar to large vessel stroke) or microembolism (concurrent
   with fat embolism syndrome)
 * Cerebral fat microembolism occurs in 1-3% of all fractures and should be suspected
   in patients with large fractures of long bones, especially lower limb bones, 
   presenting with altered mental status and headaches.
 * SWI and DWI are the most useful sequences
 * MRI imaging appearance in cerebral microembolism has been classified in three
   patterns depending upon the stage:

**Type 1: Scattered Cytotoxic Edema/starfield pattern**

 * Most Common
 * Reversible, nonspeciific in all embolic events
 * Seen in watershed zones, basal ganglia

**Type 2: Confluent Cytotoxic /vasogenic Edema in White Matter with petechiae ****
heamorrhages****; Walnut Kernel Pattern (SWI)**

 * Subacute stage (5-14 days after fracture)
 * Scattered foci of T2 and diffusion abnormality become more confluent
 * On SWI, multiple scattered microhaemorrhages are seen in both the the deep and
   subcortical white matter **(Walnut Kernel Pattern)**

**Type 3: Type 3: Chronic Sequelae (>14 days)**

 * Sequelae of infarction, cavitation, scar formation, gliosis, or chronic demyelination

**Differentials:**

 * **Diffuse Axonal Injury (DAI)**: In the setting of trauma, this is a close differential.
   Microhaemorrhages usually involve only the gray-white matter junction, with relative
   sparing of deep white matter
 * Disseminated Intravascular Coagulopathy
 * Septic Emboli

**References:**

 * Kuo KH, Pan YJ, Lai YJ, Cheung WK, Chang FC, Jarosz J. Dynamic MR imaging patterns
   of cerebral fat embolism: a systematic review with illustrative cases. AJNR. 
   2014 Jun;35(6):1052-7. doi: 10.3174/ajnr.A3605.
 * Giyab O, Balogh B, Bogner P, Gergely O, Tóth A. Microbleeds show a characteristic
   distribution in cerebral fat embolism. Insights Imaging. 2021 Mar 31;12(1):42.
   doi: 10.1186/s13244-021-00988-6.
 * Sethi D, Kajal S, Saxena A. Neuroimaging findings in a case of cerebral fat embolism
   syndrome with delayed recovery. Indian J Crit Care Med. 2015 Nov;19(11):674-7.
   doi: 10.4103/0972-5229.169350.