Abstract
Objectives: The lesion topography of medullary infarction (MI) is heterogeneous and its correlation with stroke etiology remains elusive. We aim to clarify the lesion pattern of MI and to assess its correlation with stroke etiology.Material and Methods: Of 1129 subjects with available DWI in SMART study (a multi-center trial concerning secondary stroke prevention in China) between April 2008 and December 2010, 43 patients with DWI confirmed MI (3.8%) were retrospectively evaluated. Lesions were categorized as lateral and medial medullary infarction (LMI and MMI, 33 and 10 subjects respectively) at 3 levels rostro-caudally and correlated with the stroke etiology. Clinical profiles and long-term prognosis were analyzed.Results: Large artery atherosclerosis, small vessel occlusion, cardiogenic embolism and artery dissection accounted for 29, 11, 1, and 2 infarcts, respectively. Large artery disease was the most common cause in LMI (24 of 33, 72.7%) whereas small vessel occlusion was not uncommon in MMI (5 of 10, 50.0%). Though the difference of infarct pattern between large artery atherosclerosis and small vessel occlusion was insignificant, two distinct lesion patterns were considered to be relevant: (1) Rostral MMI with continuous medial pontine infarctions were more likely attributed to small vessel occlusion than large artery atherosclerosis. Kameda et al. (2) MMI with ventral to dorsal extension were more often caused by large artery disease than small vessel occlusion. Median NIHSS at admission was 4. During a median follow-up of 17 months, 2 patients died and 2 experienced recurrent ischemic events, 39 of 41 subjects (95.1%) were functional independent (mRS 0–2).Conclusions: This multi-center study demonstrates that MI has distinct lesion pattern depending on various stroke etiologies and mechanisms. Future investigations with larger sample size should establish the lesion pattern of MI and validate its correlation with the stroke etiology and mechanisms, which might improve stroke management.
Highlights
Medullary infarction (MI) is rare, and can be classified into lateral and medial medullary infarction (LMI and MMI) based on clinical and lesion patterns
Though emboligenic heart disease was identified in 3 participants, 1 with thrombus in left atrial or ventricle and 2 with atrial fibrillation, the stroke etiology of the latter 2 patients was considered to be Large artery atherosclerosis (LAA) concerning the presence of multiple risk factors and marked atherosclerotic changes in relevant arteries
The following patterns were considered to be relevant to small vessel occlusion (SVO) or large artery atherosclerosis (LAA): [1] Two patients with ventral MMI had continuous medial pontine infarctions and categorized as SVO based on normal angiography and absence of embolism
Summary
Medullary infarction (MI) is rare, and can be classified into lateral and medial medullary infarction (LMI and MMI) based on clinical and lesion patterns. Though the management in posterior circulation infarction remained uncharted in the past decades [10], it is important to distinguish the stroke etiology and mechanism since the treatment and prognosis may differ. The arterial supply of medulla is distinct from that of the other brainstem areas. They can be divided into four arterial groups (anteromedial, anterolateral, lateral, and posterior): [1] anteromedial and anterolateral groups arising from the vertebral and anterior spinal arteries. [2] lateral group arising from the posterior inferior cerebellar artery (PICA), the vertebral artery (VA), the basilar artery (BA), and anterior inferior cerebellar artery. [3] posterior group arising from the PICA for the rostral medulla and from the posterior spinal artery for the caudal medulla. The mechanisms of MI might be different from that of other brain infarctions
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