척추 전이암에서 확산강조 자기공명 영상을 이용한 치료반응의 평가

Evaluation of Treatment Response Using Diffusion-Weighted MAI in Metastatic Spines

본 연구는 골 전이암에 대한 치료에 통상적으로 이용되는 방사선치료 후 치료반응을 객관적으로 평가하는 데 필요한 새로운 영상진단 방법의 적용 가능성을 확인하기 위하여 시행되었다. 척추에 혈행성 전이를 일으킨 21명의 환자를 대상으로 방사선치료 전 후에 확산 강조 자기공명 영상을 시행한 10명의 환자에서 방사선치료 전 후에 골수 조직의 신호 강도의 변화가 현저하였으므로 기존의 진단방법인 단순 X-선 촬영, 방사성 동위원소 골 주사, 전산화 단층 촬영 및 스핀 에코 자기공명 영상진단을 보완할 수 있다는 가능성을 확인하였다. 그렇지만 대상 환자의 숫자가 적고 추적기간이 짧기 때문에 이 촬영기법이 척추에 혈행성 골 정기가 의심되는 환자에서 기본적인 검사방법으로 자리잡기 위해서는 더 많은 화자를 대상으로 가능한 병리조직학적 검사를 병행하여 장기간에 걸쳐 전향적인 검토가 필요하다고 생각되었다.

Background: The purpose of this study was to evaluate the usefulness of diffusion-weighted magnetic resonance imaging for monitoring the response to radiation therapy in metastatic bone marrow of the spines. Materials and Methods: Twenty-one patients with metastatic bone marrow of the spines were examined with MRI. Diffusion-weighted and spin-echo MRI were performed in 10 patients before and after radiation therapy with or without systemic chemotherapy, and performed in 11 patients after radiation therapy alone. Follow up spin-echo and diffusion-weighted MRI were obtained at 1 to 6 months after radiation therapy according to patients' condition. The diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF). Signal intensity changes of the metastatic bone marrows before and after radiation therapy on conventional spin-echo sequence MRI and diffusion-weighted MRI were evaluated. Bone marrow contrast ratios and signal-to-noise ratios before and after radiation therapy of diffusion- weighted MRI were analyzed. Results: All metastatic bone marrow of the spinal bodies were hyperintense to normal bone marrow of the spinal bodies on pretreatment diffusion-weighted MRI and positive bone marrow contrast ratios(p<0.001), and hypointense to normal spinal bodies on posttreatment diffusion-weighted MRI and negative bone marrow contrast ratios(p<0.001). The signal to noise ratios after treatment decreased comparing with those of pretreatment. Decreased signal intensity of the metastatic bone marrows on diffusion-weighted MRI began to be observed at average more than one month after the initiation of the radiation therapy. Conclusion: These results suggest that diffusion-weighted MRI would be an excellent method for monitoring the response to therapy of metastatic bone marrow of the spinal bodies, however, must be investigated in a larger series of patients with longer follow up period.