Superiority of MRI for Evaluation of Sacral Insufficiency Fracture

Abstract

Study Design: Retrospective observational study. Background: Sacral insufficiency fractures (SIF) are relatively rare fractures and difficult to diagnose on plain radiographs. The primary objective of the present study was to evaluate the role of lumbar magnetic resonance imaging (MRI) for the diagnosis of SIF. The secondary objective was to identify the classification of SIF by computed tomography (CT). Methods: A total of 77 (Male 11, female 66, mean 80.3 years) people were included in this study. Inclusion criteria for this study were: age ≥60 years and no history of high energy trauma. Exclusion criteria were high energy trauma and a current history of malignancy. Differences in the fracture detection and description in the various radiologic procedures were evaluated. Fracture patterns were evaluated with CT. The detection rates of additional pathologies in the MRI of the pelvis and lumbar spine were also recorded. Results: The sensitivities for SIF were 28.5% in radiographs and 94.2% in CT, and all fractures were detected in MRI. MRI showed a more complex fracture pattern compared with CT in 65% of the cases. We observed 71.4% of single SIFs, 9.1% with other spinal fractures, 13.0% with other pelvic fractures, and 7.8% with other fractures. According to the SIF fracture pattern, the H/U type was 40.2%, transverse type was 33.7%, λ/T type was 24.7%, unilateral vertical type was 1.3%, and bilateral vertical type was 0%. Conclusions: an MRI of the lumbar spine including the sacrum with a coronal fat-suppressed T2-weighted image is useful for elderly patients with suddenly increasing low back pain at an early stage. This procedure improves an early SIF detection, recognition of concomitant pathologies, and adequate treatment for the patients.

救急外来でdual energy CTによる診断を行った高齢者脊椎骨折の3例(Three cases of vertebral fractures in elderly patients diagnosed by dual energy CT in the emergency department)

“…DECTは脊椎以外での四肢骨折診断に加えて，悪性腫瘍 9), 10)，肺動脈塞栓症 11)，尿酸結石による痛風や関節炎 10), 12), 13)，大動脈ステントグラフト留置後のエンドリーク 12)，COVID–19肺炎の重症度評価 14)に利用され有用性が報告されている。救急外来において，MRIが実施困難な詳細不明の体内金属を有する症例，あるいは長時間の検査が困難な高齢者，疼痛で安静が保持できない症例や循環動態の不安定な症例，通常のCT撮像から再構成できるため，熱源検索など他の目的で撮像した画像を利用できる点はDECTが有用であり，救急外来では汎用性が高いと考えられる。症例1では，典型的な新規の脊椎圧迫骨折が，症例2では体内に金属物のある状況で陳旧性圧迫骨折内の新規骨折が，症例3では見落とされやすい仙骨骨折が，それぞれDECTにより診断できており，MRIを補完する役割を果したと考えられる。症例3は当初仙骨骨折に気づかず，腰椎圧迫骨折疑いにてMRIが追加されている。仙骨骨折は皮質骨に骨折線を認める症例も見落とされることが報告されており，単純X線写真では5～35%の感度，CTでも見落とされることがあると報告されている 15)。DECTにて画像強調されることで診断精度の向上が期待される。…”