Magnetic Resonance Diffusion W Imaging in Cerebral Fat Embolism

Abstract

Fat embolism syndrome (FES) is a collection of signs and symptoms typically occurring 12 to 36 hours after trauma or surgery and consisting of the classical triad of respiratory insufficiency, skin petechiae, and cerebral decompensation.1,2 It is often the sequelae of displaced long bone fractures of the lower extremities, and is a potentially lethal complication. 3Neurologic involvement in FES has been termed cerebral fat embolism (CFE) and has traditionally presented a diagnostic challenge. Computed tomography (CT) has demonstrated only limited sensitivity in the diagnosis of CFE. 4,5 Traditional T1, T2, and proton density magnetic resonance imaging (MRI) sequences have proven effective in the diagnosis of CFE. [6][7][8][9] Relatively new diffusion weighted imaging (DWI) techniques used in the setting of acute cerebral stroke are more sensitive than T2 weighted imaging.10 Diffusion weighted imaging may offer improved diagnostic potential in the setting of CFE. The application of DWI in two cases of CFE is discussed. PATIENT 1A 25-year-old male presented to a major trauma center following a motorcycle accident. The patient had sustained a closed, transverse, proximal left femur fracture. There was momentary loss of consciousness at the scene with a normal admission head CT scan. The injury was treated by open reduction with intramedullary rod and screw fixation on the same day. ABSTRACT:The use of diffusion weighted imaging with apparent diffusion coefficient mapping in the diagnosis of cerebral fat embolism is shown here to demonstrate infarcts secondary to fat emboli more intensely than T2 weighted sequences 24 hours after the onset of symptoms. Embolic foci are hypointense on apparent diffusion coefficient mapping consistent with cytotoxic edema associated with cell death and restricted water diffusion. This technique increases the sensitivity for detecting cerebral fat embolism and offers a potentially important tool in its diagnosis. RÉSUMÉ: Imagerie de diffusion parrésonance magnétique dans l'embolie graisseuse cérébrale. L'utilisation de l'imagerie de diffusion par résonance magnétique avec cartographie du coefficient apparent de diffusion pour diagnostiquer l'infarctus secondaire à l'embolie graisseuse visualise mieux ces infarctus que les séquences pondérées T2, 24 heures après le début des symptômes. Les foyers emboliques sont hypointenses à la cartographie par mesure du coefficient apparent de diffusion, ce qui est compatible avec un oedème cytotoxique associé à la mort cellulaire et une diffusion aqueuse réduite. Cette technique est plus sensible pour détecter l'embolie graisseuse cérébrale et pourrait s'avérer un outil précieux pour poser ce diagnostic.

Cerebral fat embolism: diffusion-weighted magnetic resonance imaging findings

“…These lesions decreased ADC values on ADC maps. These findings are in agreement with those previously reported as 'starfield' appearancemultiple punctate foci of high signal intensity within dark background (10,12). In our study, DWI was more sensitive than T2-weighted image (DWI with b50) at the acute stage.…”

“…The configuration of these lesions was characteristically changed from tiny foci initially to large confluent lesions. These serial changes were also reported in another case report (10). Therefore, it is suggested that the vasogenic edema of CFE progresses during the course of a few days.…”

“…However, there are only a few case reports about the findings of CFE on diffusion-weighted MR imaging (DWI), a sensitive diagnostic tool for cytotoxic edema (10,12).…”

Massive cerebral involvement in fat embolism syndrome and intracranial pressure management

“…We suspect the unilateral embolization may be related to the causes of the prior contralateral ischemic stroke, but we do not have any direct evidence to support this statement. 35 We are convinced by this case and the literature find ings that neurosurgeons may be an integral part of care for the most critical portion of FES patients with cere bral involvement. Despite the fact that FES was described more than 150 years ago, diagnosis and adequate treat ment of its cerebral implications still represent a signifi cant clinical challenge.…”

Serebral Yağ Embolisinde Difüzyon Ağırlıklı Manyetik Rezonans Görüntüleme

“…Typical findings are multiple punctate hyperintensities in the subcortical and deep white matter on T2 weighted and diffusion weighted images. This is called a starfield pattern (3,5,(7)(8)(9).…”