Department of Medical Imaging, Division of Neuroradiology, Toronto Western Hospital, University Health Network, 399 Bathurst, M5T 2S8, Toronto, ON, Canada.
Department of Medical Physics, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
Clin Neuroradiol. 2021 Sep;31(3):627-631. doi: 10.1007/s00062-020-00942-x. Epub 2020 Aug 17.
Both CT myelogram (CTM) and digital-subtraction myelogram (DSM) can be used to evaluate patients for possible cerebrospinal fluid (CSF) leaks. DSM is a relatively new technique. No data exists on the radiation dose associated with this procedure, and how it compares with CTM.
All patients who underwent DSM for spontaneous intracranial hypotension (SIH) refractory to blood patching from Dec 2016 - Sept 2019 were retrospectively assessed. DSM dose factors were then recorded (cumulative fluoroscopy time, total kerma area product (KAP, mGy.cm2), cumulative air kerma (mGy), as well as CTM dose factors (included CTDIvol (mGy) and dose-length product (DLP, mGy.cm). These indices were then used to calculate the effective dose for both procedures using standardized conversion factors.
61 DSMs were performed in 42 patients, 33 of which also underwent CTM. The median effective dose was 6.6 mSv per DSM study (range: 1.2 - 17.7). On a per-patient basis (i.e. those patients who underwent more than one DSM (as the initial one was negative), the median total effective dose was 13 mSv for their total DSM imaging (range: 2.6 -31.7). For the CTM, the median effective dose was 19.7 mSv (range: 3.2 - 82.4 mSv).
The radiation dose with DSM appears to be significantly lower than that of CTM (p = 0.0005), when looking at CTM doses both from our institution and in the published literature.
CT 脊髓造影（CTM）和数字减影脊髓造影（DSM）均可用于评估疑似脑脊液（CSF）漏患者。DSM 是一种相对较新的技术。目前尚无关于该程序相关辐射剂量的资料，也无法与 CTM 进行比较。
回顾性评估了 2016 年 12 月至 2019 年 9 月期间因血液贴补治疗自发性颅内低血压（SIH）无效而行 DSM 的所有患者。然后记录 DSM 剂量因素（透视时间累计、总比释动能面积乘积（KAP，mGy.cm2）、累计空气比释动能（mGy）以及 CTM 剂量因素（包括 CT 剂量指数容积（CTDIvol，mGy）和剂量长度乘积（DLP，mGy.cm）。然后使用标准化转换因子计算两种方法的有效剂量。
42 例患者共行 61 次 DSM 检查，其中 33 例患者同时行 CTM 检查。每例 DSM 检查的有效剂量中位数为 6.6 mSv（范围：1.2-17.7）。在每位患者的基础上（即那些接受了多次 DSM 检查的患者（因为首次检查为阴性），他们总共进行的 DSM 成像的总有效剂量中位数为 13 mSv（范围：2.6-31.7）。对于 CTM，有效剂量中位数为 19.7 mSv（范围：3.2-82.4 mSv）。
与 CTM 相比，DSM 的辐射剂量明显更低（p = 0.0005），无论从我们机构还是从已发表文献来看，CTM 剂量都是如此。
