Early Diagnosis of Cerebral Fat Embolism Syndrome by Diffusion-Weighted MRI (Starfield Pattern)

Abstract

Background — Cerebral fat embolism syndrome is a rare, but potentially lethal, complication of long bone fractures. Neurological symptoms are variable, and the clinical diagnosis is difficult. The purpose of this case study is to demonstrate the value of diffusion-weighted MRI of the brain for early diagnosis of fat embolism syndrome. Case Description — A non-head-injured 18-year-old woman suffered acute mental status changes 21 hours after an uncomplicated fracture of the left tibia. MRI of the brain was performed 48 hours after injury. T2-weighted images showed multiple nonconfluent areas of high signal intensity, which, on the diffusion-weighted scans, were revealed as bright spots on a dark background (“starfield” pattern). We suggest that this indicates areas of restricted diffusion that are due to cytotoxic edema, resulting from multiple microemboli. Conclusions — High-intensity lesions in the brain on diffusion-weighted images may serve as an early-appearing and more sensitive indicator of the diagnosis of fat embolism in the clinical context of long bone injury without head trauma.

New developments in the neuroradiological diagnosis of craniocerebral trauma

“…MRI plays an important role in diagnosing this condition by showing showed multiple non-confluent areas of high signal intensity on T2-weighted and FLAIR images. On the diffusion-weighted scans, these lesions are seen in the acute phase as bright spots on a dark background ("starfield" pattern) [40]. This indicates areas of restricted diffusion that are due to cytotoxic edema, resulting from multiple microemboli.…”

Clinical and Radiographic Improvement Following Cerebral Fat Emboli

“…Clinical diagnosis of cerebral fat embolism may be aided by Gurd's diagnostic criteria [11], and should be suspected in trauma patients with long-bone fractures and otherwise unexplained neurological deterioration [12,13]. Imaging with head CT typically does not reveal abnormalities [14][15][16][17]. In contrast, MRI often demonstrates an early pattern of multiple punctuate areas of increased T2 signal, which have been described as a ''starfield pattern'' [16].…”

Susceptibility weighted imaging in a patient with paroxysmal sympathetic storms

“…PSS is not well understood and often caused by DAI [1]. When DAI and fat embolism syndrome (FES) are both observed in trauma patients, one may have difficulty differentiating delayed presentation of DAI from FES [5]. We report the use of modern MR sequence susceptibility weighted imaging (SWI) in a case of PSS secondary to delayed presentation of DAI.…”

“…Thus, DAI and FES could both be the etiology of altered consciousness in such patients. However, most patients who suffered from DAI lost consciousness immediately and those who suffered from FES were often initially lucid [4,5]. Furthermore, pulmonary, central nervous system and cutaneous manifestations could be seen in FES.…”

“…It came into question when the presentation of DAI was delayed, which was rarely seen [4]. The diagnosis may become difficult since both DAI and FES could have normal brain CT findings and disseminated hyperintense lesions on T2-weighted MRI [4,5].…”