摘要:目的: 探討磁共振波譜(MRS)對鑒別橋小腦角神經鞘瘤與腦膜瘤的價值。 方法 :對8例神經鞘瘤和8例腦膜瘤病例進行MRI平掃和增強掃描,并采用點分辨波譜序列(PRESS,TR/TE=2000/136ms)進行單體素波譜分析。從事磁共振診斷專業的醫師根據腫瘤的MRI及MRS表現特征進行鑒別診斷。 結果 :盡管多數神經鞘瘤(5/8)和腦膜瘤(6/8)具有典型的MRI表現特征并僅經MRI即可得到正確鑒別,但部分病例(5/16)為不典型表現者,如腦膜瘤呈長T1長T2信號并伴有囊變,以及神經鞘瘤呈等信號、均勻強化且不伴有囊變或內聽道擴大者,鑒別診斷困難。MRS顯示腦膜瘤的膽堿/肌酸比值(Cho/Cr)(2.74±1.47)略高于神經鞘瘤(2.70±1.21),但差異無統計學意義。丙氨酸(Ala)在腦膜瘤中的出現率(4/8)顯著高于神經鞘瘤(0/8)(Plt;0.05),谷氨酸鹽/谷氨酰胺(Glx)在腦膜瘤中的出現率(5/8)也高于神經鞘瘤(2/8);而肌醇(Ins)在神經鞘瘤中的出現率(4/8)高于腦膜瘤(2/8)。結合MRS表現,在MRI上尚難鑒別的病例可被明確診斷,并與最終病理結果相符。 結論 : MRI有助于多數橋小腦角神經鞘瘤與腦膜瘤的鑒別診斷,但對不典型病例有一定局限性;MRS對不典型病例的鑒別具有重要的參考價值。Abstract: Objective: To explore the value of magnetic resonance spectroscopy (MRS) in the differentiation of neurinoma and meningioma in the cerebellopontine angle. Methods : 16 cases, including 8 cases of meningiomas and 8 cases of neurinomas, underwent MRI (plan and gadoliniumenhanced scan) and singlevoxel proton MRS (PRESS series, TR/TE=2000/136ms). MRI and MRS results were reviewed and differential diagnoses were made by professional radiologists. Results : Although most cases (11/16) were typical and clearly classified on MRI, atypical cases were also observed, such as meningioma of long T1/T2 signal intensity with small cystic foci, and neurinoma of isointensity and homogenous enhancement without cystic change or enlargement of internal acoustic meatus. The choline to creatine ratio (Cho/Cr) of meningioma (2.74±1.47) was higher than that of neurinoma (2.70±1.21), however the difference was not significant (Pgt;0.05). Alanine was observed in 4/8 meningiomas but none of neurinomas (Plt;0.05), and glutamine/glutamate was more frequently visualized in meningiomas (5/8) than in neurinomas (2/8), whilemyoinositol was more frequently observed in neurinomas (4/8) than in meningiomas (2/8). With MRS, cases difficult to differentiate were clearly and correctly classified. Conclusion : Although most CPA neurinomas and meningiomas can be diagnosed by MRI, MRS is useful for the differential diagnosis of atypical cases.
ObjectiveTo investigate the effect of microsurgical therapy and the key techniques in resection of large bilateral olfactory groove meningiomas via unilateral subfrontal approach.MethodsThe clinical data and follow-up results of 181 patients with large bilateral olfactory groove meningiomas who underwent microsurgical removal between June 2007 and May 2014 were retrospectively analyzed. The initial symptom was headache or (and) dizzy in 95 cases, hyposmia or anosmia in 53, impairment of visual function or (and) visual field deficits in 26, cognitive deficits in 3, epilepsy in 2, and accidentally discovered in 2. Unilateral subfrontal approach was applied in all patients (neuroendoscopy was applied in some cases in the later period); incision of falxcerebri, and when necessary, ligation of superior sagittal sinus to resect contralateral tumor were performed. Simultaneous or staged period resection of tumors invading skull base such as ethmoid sinus and superior meatus and reconstruction of the skull base were performed.ResultsThere was no perioperative mortality. Simpson grade Ⅰ resection was obtained in 33 cases, grade Ⅱ resection was in 141, grade Ⅲ resection was in 4, and grade Ⅳ resection was in 3. Among the 229 eyes with preoperative visual impairment, postoperative visual improvement was found in 215 eyes, unimproved was in 12, and aggravation was in 2. The 59 sides which lost their function of olfactory nerve before surgery obtained no recoveries after surgery, while olfactory nerve with residual function preoperative still kept sensing after surgery in 149 lateral sides (149/303). The patients were followed up for (76.9±43.8) months, and postoperative recurrence or residual tumor growth were found in 21 cases.ConclusionsBecause of the contralateral ocular and (or) nasal compensation, early discovery is very difficult for patients with olfactory groove meningioma. The unilateral subfrontal approach can provide sufficient exposure for resection of large bilateral olfactory groove meningiomas and improve the visual acuity and visual field deficits. But it is poor at the preservation of olfactory function. The approach, better with the aid of neuroendoscopy, can improve the total cutting rate, with the advantages of minimally invasion and fewer complications. It is a worthy priority for these tumors.