Usefulness Evaluation of Artifacts by Bone Cement of Percutaneous Vertebroplasty Performed Patients and CT Correction Method in Spine SPECT/CT Examinations

Objectives The most commonly performed percutaneous vertebroplasty(PVP) to treat compression fracture is in the increasing trend. But, the bone cement material used in the PVP influences the image quality by forming an artifact in the CT image. Therefore, the objective of the research lies on evaluating the effect the bone cement gives to SPECT/CT image.

Methods The images were acquired by inserting model cement to each cylinder, after setting the background, hot cylinder and cold cylinder to the NEMA-1994 phantom. Non-attenuation correction(NAC), attenuation correction(AC+SC-) and attenuation & scatter correction(AC+SC+) were used for the CT correction method. The mean count by each correction method and the count change ratio by the existence of the cement material were compared and the contrast recovery coefficient(CRC) was obtained. Additionally, the bone/soft tissue(B/S) ratio was obtained by 20 patients who had the PVP.

Results AC+SC- for the quantitative count and AC+SC+ for the contrast ratio were analyzed to be the highest. The rate of mean count increase of NAC, AC+SC and AC+SC+ when cement existed showed 12.4%, 6.5%, 1.5% at the hot cylinder, 75.2%, 85.4%, 102.9% at the cold cylinder about phantom and 33.1%, 41.4%, 63.5% at the fracture region, 53.1%, 61.6%, 67.7% at the normal region about clinical image.

Conclusions The use of AC+SC- in the spine SPECT/CT examination of PVP performed patients drastically increases the image count and enables a high density image of the lesion. But it also increases the noise count of the soft tissue and the scatter area as well along with the effect of the bone cement. Therefore, it is considered to be useful in a clinical diagnosis if the application of AC+SC+ that improves the contrast ratio is combined.