Assessment of paramedian thalamic infarcts: MR imaging, clinical features and prognosis

Abstract

Considering the highly variable vascular supply of the thalamic nuclei, MRI and clinical syndromes can be heterogeneous in ischemic diseases. We attempt to determine MRI pattern and to analyse neurological features and prognosis of paramedian infarcts. In a prospective case series within 5 years from 1999 to 2003, MRI, MRA and clinical symptoms of 38 consecutive patients were analysed. The inferomedial (posterior thalamoperforating artery) territory was affected in 89%, and lesions in the anterolateral (tuberothalamic artery) territory occurred in 42%. However, definite attribution to anterolateral or inferomedial territories was not possible in 13%. Neurological manifestations were somnolence (87%), hemisyndromes (79%), cognitive deficits (58%), oculomotor nerve palsies (53%) and vertical gaze palsies (39%). The most common aetiologies were cardiac embolism (42%), intraarterial embolism (16%), small vessel disease (13%) and large artery arteriosclerosis (13%). Pathological MRA findings were encountered in 55%, and in 18%, lesions were only visible on diffusion-weighted imaging. Correlation of MRI pattern and neurological symptoms points out anterolateral thalamic lesions as the cause of amnestic deficits. Intracranial MRA allows a non-invasive prediction of basilar tip occlusion. Our results underline the necessity of additional diffusion-weighted imaging in detecting small thalamic and midbrain lesions.

Artery of Percheron Infarction: Imaging Patterns and Clinical Spectrum

“…4,9,19,24,25 The AOP is rarely visualized with conventional angiography, and to our knowledge, only 3 other authors have successfully demonstrated this variant. 18,26,27 We were able to capture a striking image of the AOP with conventional angiography in 1 of our patients (Fig 6). Several clinical stroke patterns potentially involving the AOP have been described, including bilateral paramedian thalamic, 5,10,15 paramedian and polar thalamic, 16 and paramedian thalamic and mesencephalic.…”

“…1,2,6,[9][10][11][12][13] Many authors have demonstrated that the paramedian arteries can supply both the paramedian and the anterior thalamic territories, especially when the polar artery is absent. 1,4,6,9,10,[14][15][16][17][18][19] The variable presence of the polar artery (absent in 30%-60% of the population) 7,15,16 is not surprising because it arises from the PcomA, which itself is highly variable and can be absent or hypoplastic. One case series reported 7 of 8 bilateral paramedian thalamic infarcts extended into the anterior thalamic territory of the polar artery.…”

Differential Diagnosis of Bilateral Thalamic Lesions

“…Furthermore, the anterior choroidal artery (AchA) can also be involved in supplying the lateral thalamus; however, the question of its contribution to vascular supply is still controversial [4][5][6]. Four main vascular territories are differentiated on the basis of the most important infarct patterns: the anterolateral, the inferomedial, the inferolateral, and the posterolateral regions of supply ( Figure 3a).…”

“…The medial posterior choroidal arteries consist of one to two blood vessels originating from the distal P1 or the proximal P2 segment. The posterior lateral choroidal arteries can number up to six and originate from the distal P2 or the proximal P3 segments of the PCA [4][5][6].…”

Recent Advances in Magnetic Resonance Imaging in Posterior Circulation Stroke: Implications for Diagnosis and Prognosis

“…Even considering that spatial resolution is not optimal to detect very small ischemic lesions and possible susceptibility effects in the posterior fossa, there is still a lack of DSC studies of the posterior circulation. & Weidauer et al [16] used DSC perfusion MRI for a more detailed characterization of paramedian thalamic infarction and were able to demonstrate a hypoperfusion in the PCA territory due to occlusion or severe stenosis of the distal basilar artery and/or the P1-segments of the PCA. & In a more recent prospective study, we demonstrated the feasibility and value of DSC perfusion MRI in acute pontine stroke [17••].…”