Imaging Collateral Circulation

Lee, Christabel E. C.; Ng, H. B. Ivan; Yip, Chun Wai; Lim, C. C. Tchoyoson

doi:10.1001/archneur.62.3.492

Cited by 5 publications

(2 citation statements)

References 2 publications

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“…Such failure could be due to diminished capillary density in the affected muscles (40), which would not be detected by either ABI or angiography nor be reversed by surgery. Conversely, as suggested by numerous studies (6,24,42,52), muscle hypoperfusion due to arterial stenosis may be compensated by newly grown collateral arteries in some patients with PAD; for these patients, invasive surgical treatment should not be applied (42,64). With the proposed method, we can assess the effects of vascular disease on exercise-stimulated muscle perfusion.…”

Section: Elderly Healthy Subjectsmentioning

confidence: 99%

Exercise-induced calf muscle hyperemia: quantitative mapping with low-dose dynamic contrast enhanced magnetic resonance imaging

Zhang

Layec

Hanrahan

et al. 2019

American Journal of Physiology-Heart and Circulatory Physiology

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Peripheral artery disease (PAD) in the lower extremities often leads to intermittent claudication. In the present study, we proposed a low-dose DCE MRI protocol for quantifying calf muscle perfusion stimulated with plantar flexion and multiple new metrics for interpreting perfusion maps, including the ratio of gastrocnemius over soleus perfusion (G/S; for assessing the vascular redistribution between the two muscles) and muscle perfusion normalized by whole body perfusion (for quantifying the muscle’s active hyperemia). Twenty-eight human subjects participated in this Institutional Review Board-approved study, with 10 healthy subjects ( group A) for assessing interday reproducibility and 8 healthy subjects ( group B) for exploring the relationship between plantar-flexion load and induced muscle perfusion. In a pilot group of five elderly healthy subjects and five patients with PAD ( group C), we proposed a protocol that measured perfusion for a low-intensity exercise and for an exhaustion exercise in a single MRI session. In group A, perfusion estimates for calf muscles were highly reproducible, with correlation coefficients of 0.90–0.93. In group B, gastrocnemius perfusion increased linearly with the exercise workload ( P < 0.05). With the low-intensity exercise, patients with PAD in group C showed substantially lower gastrocnemius perfusion compared with elderly healthy subjects [43.4 (SD 23.5) vs. 106.7 (SD 73.2) ml·min−1·100 g−1]. With exhaustion exercise, G/S [1.0 (SD 0.4)] for patients with PAD was lower than both its low-intensity level [1.9 (SD 1.3)] and the level in elderly healthy subjects [2.7 (SD 2.1)]. In conclusion, the proposed MRI protocol and the new metrics are feasible for quantifying exercise-induced muscle hyperemia, a promising functional test of PAD. NEW & NOTEWORTHY To quantitatively map exercise-induced hyperemia in calf muscles, we proposed a high-resolution MRI method shown to be highly reproducible and sensitive to exercise load. With the use of low contrast, it is feasible to measure calf muscle hyperemia for both low-intensity and exhaustion exercises in a single MRI session. The newly proposed metrics for interpreting perfusion maps are promising for quantifying intermuscle vascular redistribution or a muscle’s active hyperemia.

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Section: Elderly Healthy Subjectsmentioning

confidence: 99%

Exercise-induced calf muscle hyperemia: quantitative mapping with low-dose dynamic contrast enhanced magnetic resonance imaging

Zhang

Layec

Hanrahan

et al. 2019

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

show abstract

“…This study showed that compared with the gold standard DSA grades for PC detection, semiquantitative grading based on TOF-MRAsi has good sensitivity and specificity, and demonstrated that mRS tended to be lower in patients with good PC grades based on TOF-MRAsi, although the relation between PC TOF-MRAsi grade and DWI infarct volume at admission were not significant because the time from the qualifying event to TOF-MRAsi was about 7 days in patients with ischemic stroke. Previous studies have shown that in patients with MCATO with good PC, there is higher vascular signal intensity at the distal end of the MCATO segment in fluid-attenuated inversion recovery sequences, 12 increased cortical branches in the ipsilateral posterior cerebral artery in three-dimensional MRA images, 13 greater difference in blood flow between lesions and the contralateral posterior cerebral artery in quantitative MRA, 14 and lower degree of cerebral blood flow decrease on dynamic magnetic resonance perfusion (MRP) images. 15 These studies indirectly suggest a correlation between TOF-MRAsi and PC.…”

Section: Discussionmentioning

confidence: 99%