Abstract:
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Purpose: To qualitatively and quantitatively evaluate the effect of Subtraction postprocessing technique in gadolinium-enhanced spinal imaging of postoperative patients with metallic hardware.
Methods and Materials: Fifteen spinal postoperative patients(8 males, 7 females ; mean age 49.4 years, range 27 to 68) with metallic hardware underwent MR(1.5T Signa MR/i, General Electric, Milwaukee wisconsin, USA). Postprocessing images were obtained by subtraction of T1 weighted images(T1 WI) from gadolinium enhanced T1 WI. Regions of interest were drawn over the spinal postoperative fibrotic area and paraspinal muscle at the corresponding level of previous surgery on precontrast T1 WI and postcontrast T1 WI for measuring contrast to noise ration(CNR). Qualitative evaluation was performed independently by three radiologists for the detection rate of postoperative changes at the level of corresponding axial images and the effect of metallic artifact using five grade-scoring scale.The statistical analysis was performed using Paired T-Test.
Results: In quantitative study, mean CNR of subtraction images(22.94) was significantly higher than those of the gadolinium enhanced T1 WI(9.79).(p<0.05) In qualitative study, mean scores of the detection rates on subtraction images and postcontrast T1 WI were 3.98 and 2.44, respectively. Mean scores of the effects of metallic artifact were 2.67 and 2.13, respectively. Both scores were statistically significant(p<0.05).
Conclusion: By using subtraction postprocessing technique in contrast-enhanced MR imaging in postoperative patients with metallic hardware, fat suppression and reducing metallic artifact provides the possibility to increase sensitivity of postoperative complications with cost-free option.
Cha MD, J,
Subtraction Postprocessing MR Imaging in Postoperative Patients with Metallic Hardware. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3108349.html
