ORIGINAL ARTICLE - VASCULAR
Signal reduction of donor artery on MRI after superficial
temporal artery to middle cerebral artery anastomosis:
a retrospective analysis
Received: 1 January 2017 /Accepted: 16 February 2017 /Published online: 9 March 2017
Springer-Verlag Wien 2017
Object Microsurgical anastomosis from the superficial tem-
poral artery (STA) to the middle cerebral artery (MCA) is a
treatment option for appropriately selected patients with cra-
nial atherosclerotic steno-occlusive disease (CASD).
However, the long-term efficacy and patency of the donor
artery remain unclear. We reviewed the signal intensity of
the donor artery on magnetic resonance angiography (MRA)
after STA-MCA anastomosis in patients with CASD and clar-
ified the incidence of and risk factors for reduction in postop-
erative signal of STA.
Methods From April 2007 to March 2015, 155 STA-MCA
anastomosis operations for CASD were performed at our in-
stitute. The postoperative imaging findings of 112 patients
with available follow-up data for more than 3 months were
Results Over a median follow-up of 24 months, the signal of the
donor artery on MRA became weaker than that on MRA per-
formed immediately after surgery in 30 (27%) patients. The rates
of signal reduction at 1 and 2 years after surgery were 18 and
25%, respectively. Multivariate analysis revealed that a high
STA bifurcation (p = 0.015; odds ratio, 7.14) and the presence
of chronic kidney disease (p = 0.011; odds ratio, 5.59) were in-
dependent risk factors for postoperative signal reduction.
Conclusions Our results suggest that the signal intensity of
the donor artery of an established STA-MCA bypass de-
creases in many cases. Both the loose entrance of the STA to
the dura and systemic atherosclerosis are related to postoper-
ative vessel remodeling.
Superficial temporal artery
Cranial atherosclerotic steno-occlusive disease (CASD) is one
of the most common vascular abnormalities in patients with
ischemic stroke .TheprognosisofCASDisworsethanthat
of other stroke etiologies, and the rates of recurrent stroke and
death are between 15 and 25% per year, despite maximal med-
ical therapy . To salvage these patients, direct cerebral revas-
cularization involving anastomosis from the superficial temporal
artery (STA) to the middle cerebral artery (MCA), if performed
under rigorous patient selection, is reported to be an effective
modality for preventing recurrent ischemic stroke [7, 8].
Although large randomized, controlled studies have failed to
show its efficacy, the inferiority of the bypass group is mainly
due to complications in the acute phase, and the long-term effect
of the surgery has yet to be validated thoroughly [15, 16].
Nevertheless, postoperative patency of the anastomosis re-
mains empirical at present . Even in patients with excel-
lent blood flow immediately after bypass surgery involving
STA-MCA anastomosis, a reduction in blood flow could oc-
cur over time. However, few studies have evaluated for late
reduction in blood flow after this procedure, especially when
the surgery is performed for patients with CASD .
In the present study, we retrospectively reviewed the signal
intensity of the donor artery on magnetic resonance angiogra-
phy (MRA) after bypass surgery involving STA-MCA anas-
tomosis for CASD. We also elucidated the incidence and risk
factors associated with postoperative signal reduction.
* Toshikazu Kimura
Department of Neurosurgery, NTT Medical Center Tokyo, 5-9-22
Higashi-Gotanda, Shinagawa-ku, Tokyo 141-8625, Japan
Department of Neurosurgery, The University of Tokyo, Tokyo, Japan
Acta Neurochir (2017) 159:1679–1685