New approach for assessing vascular distribution within bone tumors using dynamic contrast-enhanced MRI.
OBJECTIVE
To differentiate benign from malignant bone tumors by analyzing the vascular distribution within bone tumors with dynamic contrast-enhanced MRI.


METHODS
We studied dynamic contrast-enhanced MRI for 49 bone tumors (22 malignant and 27 benign tumors). Seven small regions of interest (ROI) were set inside the largest portion of each tumor. Four ROI were placed evenly on the periphery and three ROI were placed evenly on the line of the longest breadth within the tumor. The slope of the curve (%Slope) was calculated on the time-intensity curves of the whole tumor and of each ROI. The variance values for the %Slope of the ROI were calculated to assess the dispersion of the intensity change at each ROI within the tumor.


RESULTS
Mean value of the %Slopes of whole tumor regions for malignant bone tumors (70.4 +/- 60.3%) was significantly higher than that for benign bone tumors (37.6 +/- 52.9%) (P = 0.015), although giant cell tumor (GCT), a locally aggressive tumor, had a relatively higher %Slope. Mean value of the variance of %Slopes for malignant bone tumors (3485.9 +/- 5942.5) was significantly higher than that for all benign tumors (470.4 +/- 583.9) (P = 0.012), indicating that the %Slope values of seven ROI within malignant bone tumors varied more widely compared with the ROI inside benign bone tumors. GCT also demonstrated a lower value.


CONCLUSIONS
Our method of analyzing the signal intensity change at seven separate regions that evaluates the vascular distribution within a tumor could be a useful tool for differentiating between benign and malignant bone tumors.
Kawakami
Yukio
Y
Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama, 700-8558, Japan.
Kunisada
Toshiyuki
T
Sugihara
Shinsuke
S
Ono
Atsushi
A
Nishida
Keiichiro
K
Abe
Nobuhiro
N
Kawai
Akira
A
Fujiwara
Kazuo
K
Morimoto
Yuki
Y
Ozaki
Toshifumi
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000098:blood supply* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology