颅内囊性肿块病变的质子磁共振波谱和扩散加权成像

Proton magnetic resonance spectroscopy and diffusion-weighted imaging in intracranial cystic mass lesions.

作者信息

Lai Ping-Hong, Hsu Shu-Shong, Ding Shang-Wu, Ko Cheng-Wen, Fu Jui-Hsun, Weng Mei-Jui, Yeh Lee-Ren, Wu Ming-Ting, Liang Huei-Lung, Chen Clement-Kuen, Pan Huay-Ben

机构信息

Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Republic of China.

出版信息

Surg Neurol. 2007;68 Suppl 1:S25-36. doi: 10.1016/j.surneu.2007.07.080.

DOI:10.1016/j.surneu.2007.07.080

PMID:17963918

Abstract

BACKGROUND

The differential diagnosis of various intracranial cystic lesions is sometimes difficult on the basis of CT or MRI findings. Our objective was to evaluate (1)H MRS and DWI in the differential diagnosis of these lesions and in comparison with conventional MRI.

METHODS

Fifty patients with intracranial cystic lesions (21 pyogenic abscesses, 23 tumor cysts, 3 epidermoid cysts, and 3 arachnoid cysts) were evaluated with conventional MRI, DWI, and in vivo (1)H MRS. Preoperative diagnosis of the lesions was based on the results of DWI and in vivo MRS. All DWI and (1)H MRS studies were performed with a clinical 1.5-T system. The DWI was performed using single-shot spin-echo echo-planar pulse sequence with b = 1000 s/mm(2). The ADC value was measured. Diagnostic accuracy of conventional MRI, DWI, and in vivo (1)H MRS was calculated with respect to a final diagnosis of brain abscess vs nonabscess cystic tumor.

RESULTS

Lactate and cytosolic amino acids with/without succinate, acetate, and alanine were observed in 18 of 21 cases of abscesses on MRS. In 3 cases of epidermoid cysts, lactate was observed and could be differentiated from 3 cases of arachnoid cysts, which showed only minimal lactate. Only lactate was seen in 14 of 23 patients with tumor cysts, whereas both lipid/lactate and choline were visible in 9 patients with tumor cysts. Increased signal was seen in 20 of 21 patients with abscesses and 3 patients with epidermoid cysts on DWI. Decreased signal was observed in 22 of 23 patients with tumor cysts and 3 patients with arachnoid cyst on DWI. Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of conventional MRI for the differentiation of brain abscess from nonabscess cystic tumor were 61.4%, 61.9%, 60.9%, 59.1%, and 63.6%, respectively, whereas they were 93.2%, 85.7%, 100%, 100%, and 88.5% with MRS; 95.5%, 95.2%, 95.7%, 95.2%, and 95.7% with DWI; and 97.7%, 95.2%, 100%, 100%, and 95.8% with MRS and DWI. Magnetic resonance imaging, when combined with in vivo MRS and DWI, accurately predicted the diagnosis in 47 (94%) of 50 and 48 (96%) of 50 of the cases, respectively.

CONCLUSIONS

Proton MRS and DWI are useful as additional diagnostic modalities in differentiating intracranial cystic lesions. Combination of DWI with calculated ADC values and metabolite spectrum acquired by MRS add more information to MRI in the differentiation of intracranial cystic mass lesions.

摘要

背景

基于CT或MRI表现，各种颅内囊性病变的鉴别诊断有时存在困难。我们的目的是评估（1）氢质子磁共振波谱（1H MRS）和扩散加权成像（DWI）在这些病变鉴别诊断中的价值，并与传统MRI进行比较。

方法

对50例颅内囊性病变患者（21例化脓性脓肿、23例肿瘤性囊肿、3例表皮样囊肿和3例蛛网膜囊肿）进行了传统MRI、DWI及活体1H MRS检查。根据DWI和活体MRS的结果对病变进行术前诊断。所有DWI和1H MRS检查均采用临床1.5-T系统进行。DWI采用单次激发自旋回波平面脉冲序列，b值=1000 s/mm²，测量表观扩散系数（ADC）值。根据脑脓肿与非脓肿性囊性肿瘤的最终诊断结果，计算传统MRI、DWI和活体1H MRS的诊断准确性。

结果

在21例脓肿患者中，18例在MRS上观察到乳酸及含或不含琥珀酸、乙酸和丙氨酸的胞质氨基酸。在3例表皮样囊肿中观察到乳酸，可与3例蛛网膜囊肿相鉴别，后者仅见微量乳酸。23例肿瘤性囊肿患者中，14例仅见乳酸，而9例肿瘤性囊肿患者可见脂质/乳酸和胆碱。21例脓肿患者和3例表皮样囊肿患者在DWI上表现为信号增高。23例肿瘤性囊肿患者中的22例和3例蛛网膜囊肿患者在DWI上表现为信号减低。传统MRI鉴别脑脓肿与非脓肿性囊性肿瘤的诊断准确性、敏感性、特异性、阳性预测值和阴性预测值分别为61.4%、61.9%、60.9%、59.1%和63.6%，而MRS分别为93.2%、85.7%、100%、100%和88.5%；DWI分别为95.5%、95.2%、95.7%、95.2%和95.7%；MRS和DWI联合应用分别为97.7%、95.2%、100%、100%和95.8%。磁共振成像联合活体MRS和DWI时，分别在50例中的47例（94%）和48例（96%）中准确预测了诊断。