Blood Oxygen Level–Dependent Functional Magnetic Resonance Imaging in Preoperative Brain Mapping and Making Surgical Decisions

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HKF Mak, L Zhang, ST Feng, DKW Yeung, DTM Chan, XL Zhu, WS Poon

Hong Kong J Radiol 2011;14:147-54

Objective: To evaluate the efficacy of blood oxygen level–dependent functional magnetic resonance imaging in the preoperative mapping of sensorimotor cortices and language areas, and its impact on surgical decisions.

Methods: Fourteen patients with tumours or vascular malformations underwent functional magnetic resonance imaging (in the course of motor, sensory, and language tasks) and had structural magnetic resonance imaging scans in a 1.5T scanner. The functional magnetic resonance imaging findings were then correlated with their operative and clinical outcomes. Seven patients had a craniotomy with general anaesthesia, three had awake craniotomy with intraoperative mapping, two had radiosurgery, and two had no surgery.

Results: The technical success rate of functional magnetic resonance imaging signal activation in identifying eloquent cortices was 100% for all tasks except Chinese reading, for which the success rate was 83%. Functional magnetic resonance imaging mapping accuracy was determined by correlation with intraoperative cortical stimulation or somatosensory-evoked potentials phase reversal. Surgical decision making was influenced by functional magnetic resonance imaging in 75% of the patients, using a more aggressive approach in two patients and a safer approach in two others (due to lesion proximity of <2 cm from eloquent centres). More conventional craniotomies were performed in five patients due to larger margins (>2 cm) or contralateral location of the language centre. In one patient, there were conflicting results between Wada test and functional magnetic resonance imaging with respect to speech lateralisation; intraoperative cortical stimulation found that functional magnetic resonance imaging correctly predicted the side of speech dominance.

Conclusion: Blood oxygen level–dependent functional magnetic resonance imaging had a high technical success rate and was very accurate in mapping eloquent cortical areas preoperatively. Its role in preoperative surgical assessment is pivotal, and is recommended for most, if not all, resective brain surgery.



血氧水平依賴腦功能磁共振成像對於 術前研究腦功能區活動的效用及對手術方式的影響


目的:評估血氧水平依賴腦功能磁共振成像對於術前研究感應運動腦皮質區及語言區活動的效用, 以及對手術方式採用決定的影響。

方法:14名患有腫瘤或血管畸形的病人接受功能磁共振成像(通過運動、感覺及語言任務)及1.5T 的結構磁共振成像。並探討功能磁共振成像的結果與術中及臨床結果的相關性。最終共有7名病人接 受全身麻醉的顱骨切開術、3人接受喚醒麻醉的顱骨切開術及術中成像、2人接受放射外科手術、2人 未有接受手術。

結果:使用功能磁共振成像的信號強度辨認語言功能區的技術性成功率為100%,但閱讀中文方面則 只有83%。腦功能磁共振成像的準確度的驗證取决於術中皮層電刺激或皮層體感誘發電位逆轉。有 75%病人因功能磁共振成像的結果而影響其做手術方式的決定,其中2人採用更進取的方法,另2人 因病灶距離語言功能區只有不足2 cm,所以採用較安全的方法。另5人由於距離大(超過2 cm)或語 言區在對側位置,遂進行傳統的顱骨切開術。另1人的瓦達測試(Wada test)與功能磁共振成像在語 言側化方面的結果矛盾,後進行術中皮層電刺激測試確定功能磁共振成像正確預測語言區優勢的一 邊。

結論:血氧水平依賴腦功能磁共振成像有較高技術成功率,在術前辨認語言功能區方面相當準確。 此技術對於術前評估起了關鍵作用,可推薦作大部分腦腫瘤切開術用作術前評估。