Enhancing box sign : enhancement pattern of acute osteoprotic compression fracture.
OBJECTIVE
Although gadolinium enhancement of compression fractures is well known, the enhancement pattern of the acute stage of a fracture is not completely understood. Here, we investigated the enhancement pattern of acute vertebral compression fractures (VCFs).


METHODS
We conducted a retrospective study of patients with acute osteoporotic VCFs admitted to hospital between January 2004 and December 2005. The demographic details, stage of the fracture, management data, and results were analyzed. There were nine men and 22 women, and the mean age was 71 years (range, 53-92 years). According to the onset of pain, patients were divided into the following four groups : Group I (less than 3 days), Group II (4-7 days), Group III (8-14 days), and Group IV (14-30 days).


RESULTS
All patients had central low-signal intensity of the nonenhancing part of vertebral bodies on T1 images. Enhancing box sign (EBS) was seen 7 days of VCF development. After 7 days of onset (Groups III and IV), patch or Kummell's enhancements occurred. EBS has been statistically correlated with stage of compression fracture (Pearson's correlation = -0.774). However, EBS had no statistically significant correlation with prognosis in our study (Pearson's correlation = 0.059).


CONCLUSIONS
EBS represents a characteristic sign 7 days of VCF development.
Kim
Choong-Hyo
CH
Department of Neurosurgery, Kangwon National University College of Medicine, Chuncheon, Korea.
Park
Jae Hyo
JH
Chung
Sang Ki
SK
Kim
Ki-Jeong
KJ
Bang
Jae Seung
JS
Kim
Hyun-Jib
HJ