Weston Philippa, Behr Sebastien, Garosi Laurent, Maeso Christian, Carrera Ines
Willows Veterinary Centre and Referral Service, Linnaeus Veterinary Ltd., Birmingham, United Kingdom.
Vet Oracle Teleradiology, Norfolk, United Kingdom.
Front Vet Sci. 2022 Sep 20;9:932185. doi: 10.3389/fvets.2022.932185. eCollection 2022.
Magnetic resonance imaging (MRI) signal changes associated with ischemic stroke are typically described as T2w and FLAIR hyperintense, and T1w isointense lesions. Intralesional T1w hyperintensity is generally attributed to either a hemorrhagic stroke, or an ischemic stroke with hemorrhagic transition, and has an associated signal void on gradient echo (GE) sequences. Cases of ischemic stroke with T1w hyperintense signal in absence of associated signal void on GE sequences have been sporadically demonstrated in human stroke patients, as well as in dogs with experimentally induced ischemia of the middle cerebral artery. This multicenter retrospective descriptive study investigates the presence of T1w hyperintensity in canine stroke without associated signal void on GE sequences. High field (1.5 Tesla) MRI studies of 12 dogs with clinical presentation, MRI features, and cerebrospinal fluid results suggestive of non-hemorrhagic stroke were assessed. The time between the observed onset of clinical signs and MRI assessment was recorded. All 12 patients had an intralesional T1w hyperintense signal compared to gray and white matter, and absence of signal void on T2w GE or SWI sequences. Intralesional T1w hyperintensities were either homogenously distributed throughout the entire lesion (6/12) or had a rim-like peripheral distribution (6/12). The mean time between the recorded onset of clinical signs and MRI assessment was 3 days; however, the age range of lesions with T1w hyperintense signal observed was 1-21days, suggesting that such signal intensities can be observed in acute, subacute, or chronic stages of ischemic stroke. Follow-up was recorded for 7/12 cases, all of which showed evidence of neurological improvement while in hospital, and survived to discharge. Correlation of the age and MRI appearance of lesions in this study with similar lesions observed in human and experimental studies suggests that these T1w hyperintensities are likely caused by partial tissue infarction or selective neuronal necrosis, providing an alternative differential for these T1w hyperintensities observed.
与缺血性中风相关的磁共振成像（MRI）信号变化通常被描述为T2加权像和液体衰减反转恢复序列（FLAIR）高信号，以及T1加权像等信号病变。病灶内T1加权像高信号通常归因于出血性中风或伴有出血转化的缺血性中风，并且在梯度回波（GE）序列上有相关的信号缺失。在人类中风患者以及实验性诱导大脑中动脉缺血的犬类中，偶尔会发现缺血性中风病例在GE序列上没有相关信号缺失但T1加权像呈高信号。这项多中心回顾性描述性研究调查了犬类中风中在GE序列上没有相关信号缺失的T1加权像高信号的存在情况。对12只具有临床表现、MRI特征和脑脊液结果提示非出血性中风的犬进行了高场（1.5特斯拉）MRI研究。记录了观察到临床症状发作与MRI评估之间的时间。所有12只患者的病灶与灰质和白质相比均有病灶内T1加权像高信号，并且在T2加权像GE或磁敏感加权成像（SWI）序列上没有信号缺失。病灶内T1加权像高信号要么均匀分布于整个病灶（6/12），要么呈边缘样周边分布（6/12）。记录的临床症状发作与MRI评估之间的平均时间为3天；然而，观察到的具有T1加权像高信号的病灶年龄范围为1 - 21天，这表明在缺血性中风的急性、亚急性或慢性阶段都可以观察到这种信号强度。对12例中的7例进行了随访，所有病例在住院期间均显示出神经功能改善的证据，并存活至出院。本研究中病灶的年龄与MRI表现与在人类和实验研究中观察到的类似病灶的相关性表明，这些T1加权像高信号可能是由部分组织梗死或选择性神经元坏死引起的，可以为观察到的这些T1加权像高信号提供另一种鉴别诊断。
