Electrical stimulation therapy improves sleep respiratory parameters in obstructive sleep apnea syndrome: a meta-analysis.

Recent clinical trials have shown that electrical stimulation has beneficial effects in obstructive sleep apnea syndrome (OSAS). The purpose of this study was to evaluate the efficacy of electrical stimulation therapy for OSAS with a meta-analysis. The meta-analysis of all relative studies was performed through searching international literature, including PUBMED, CNKI, and EMBASE databases. This literature analysis compared all patients undergoing electrical stimulation therapy with respect to the respiratory disturbance index (RDI) and changes in sleep structure. Six studies were selected involving a total of 91 patients. The meta-analysis indicated that electrical stimulation therapy reduced RDI, longest apnea time, and improved the minimum SaO2. Based on the evidence found, electrical stimulation may be a potential therapy for OSAS, warranting further clinical trials.

[Diffusion weighted imaging features of normal uterine cervix and cervical carcinoma].

BACKGROUND & OBJECTIVE: Magnetic resonance imaging (MRI) is a feasible method to detect, diagnose and stage cervical cancer. This study was to analyze the diffusion weighted imaging (DWI) features of normal uterine cervix and cervical carcinoma, and assess the values of DWI in diagnosis and monitor of cervical carcinoma after radiotherapy. METHODS: Routine MRI sequence and axial diffusion weighted sequence (b=800 s/mm2) were performed in 20 patients with cervical carcinoma and in 16 healthy women as control. The apparent diffusion coefficient (ADC) values of normal uterine cervix and cervical carcinoma were compared. The ADC values of 7 cervical carcinoma patients before and after radiotherapy were compared. RESULTS: Normal uterine cervix presented 3 layers in DWI. The ADC value was significantly higher in normal uterine cervix than in cervical carcinoma [(1.71+/-0.14) x 10-3 mm2/s vs. (0.97+/-0.13) x 10(-3) mm2/s, P<0.01]. The ADC value of cervical carcinoma after radiotherapy was higher than that before radiotherapy [(1.49+/-1.40) x 10(-3) mm2/s vs. (1.02+/-0.06) x 10(-3) mm2/s], but was still lower than that of normal uterine cervix. CONCLUSION: DWI could be used to distinguish cervical carcinoma from normal uterine cervix, evaluate the extension of cervical carcinoma before therapy, and monitor the treatment response of cervical carcinoma after radiotherapy.

[Clinical significance of diffusion-weighted MRI with STIR-EPI in differential diagnosis of cervical lymph nodes].

OBJECTIVE: To evaluate the feasibility and efficacy of a new MRI imaging method--diffusion weighted imaging (DWI) with short TI version recovery-echo planar imaging (STIR-EPI) sequence in differentiating benign cervical lymph nodes from malignant ones. METHODS Twenty nasopharyngeal carcinoma patients and fourteen volunteers received both conventional MRI and DWI with STIR-EPI. Ability of detecting lymph nodes between conventional MRI and STIR-EPI-DWI was compared, and the difference of apparent diffusion coefficient (ADC) value between metastatic lymph node and normal lymph node was analyzed. RESULTS: DWI was more sensitive in detecting lymph node than conventional MRI. ADC value of metastatic lymph node (0. 766 +/- 0. 119) x 10 (-3) mm(2)/s was significantly lower than that of normal lymph node (0. 975 +/- 0. 179) x 10 - mm2/s (P < 0. 01). CONCLUSION: As a new MRI imaging technique in detecting cervical lymph nodes, diffusion weighted imaging ( DWI) with short TI version recovery-echo planar imaging ( STIR-EPI) sequence is more reliable and sensitive than conventional MRI imaging, providing an alternative way to differentiate benign lymph nodes from malignant ones.

[Three-dimensional reconstruction and image fusion between liver focal lesions and dynamic contrast-enhanced magnetic resonance angiography].

BACKGROUND & OBJECTIVES: Identifying the correlation of focal lesions to the liver vessel system is a key factor in selecting treatment patterns for focal hepatic diseases. This study was to evaluate the feasibility of 3-dimensional reconstruction and the fusion image between the 3-dimensional dynamic contrast-enhanced magnetic resonance angiography (3D DCE MRA) and the focal hepatic lesions, and further, explore the clinical application of this method. METHODS: 3D DCE-MRA and conventional magnetic resonance imaging (MRI) were performed. The angiography and focal hepatic lesions were reconstructed with maximum intensity projection (MIP) and surface shaded display (SSD), and then fused together. Of the 25 cases with evaluable images, 2 were hemangioma, 3 were focal nodular hyperplasia, 1 was hepatocellular adenoma, 2 were macroregenerative nodule, 2 were hepatobiliary cystadenocarcinoma, and 17 were hepatocellular carcinoma; 21 were confirmed by operation resection, and 4 received digital subtraction angiography (DSA). RESULTS: The anatomic relationship between the lesions and the vessels were well shown. Of the 27 cases, 5 showed normal vessel branching, 6 showed feeding arteries from the hepatic artery, 11 showed compressed and shifted trunks of the vessels, 6 showed tumor invaded vessels, and 11 showed the tumor embolism in the portal vein or the inferior vena cave; 9 also showed MRI signs of portal hypertension. MIP was prior to SSD in demonstrating small branches of the hepatic vessels. CONCLUSION: The 3-dimensional reconstruction and fusion images between 3D DCE-MRA and the focal hepatic lesions by using MIP and SSD can easily display the anatomic relationship between the focal hepatic lesions and the hepatic vessels, and thus can help the surgeons to localize lesions, minimize operating time and decide the extent of surgical resection.

[Types of liver metastases on MR imaging and characteristics of uncommon types].

BACKGROUND & OBJECTIVE: Although liver metastases are very common, some of them would be misdiagnosed because of their specific appearance on imaging. This study was to summarize the types of liver metastases according to the magnetic resonance imaging (MRI) appearance, and explore the characteristics of uncommon types to improve the accuracy of diagnosis. METHODS: A total of 174 consecutive patients with liver metastases were screened from the patients with diagnosis or suspicion of liver metastases according to plate or enhanced MRI scan. Liver metastases were confirmed through pathologic examination, medical imaging, or follow-up. Lesions were categorized as nodular, segment, and diffusion classes by shape, and categorized as common, mimicking hemangioma, and mimicking cyst patterns according to the characteristics of signal intensity. RESULTS: Common primary tumors of liver metastases were colon and rectum carcinomas (31.0%). According to the shape of lesions, the proportions of nodular, segment, and diffusion classes were 96.6%, 2.3%, and 1.1%, respectively. According to the characteristics of signal intensity, the proportions of common, mimicking hemangioma, and mimicking cyst patterns were 87.9%, 4.0%, and 8.1%, respectively. CONCLUSIONS: Most liver metastases are nodular in shape, and present as common pattern, but some uncommon types also exist. MRI scan and clinical follow-up could increase the accuracy of diagnosis.

[Significance of dynamic enhanced MRI in differential diagnosis of radiofibrosis and recurrent nasopharyngeal carcinoma at the basilar clivus].

BACKGROUND & OBJECTIVE: Basilar clivus is a common site of recurrent nasopharyngeal carcinoma (RNPC). Biopsy of the basilar clivus is seldom done because of its deep location and complex anatomic structure, therefore, early differential diagnosis of radiofibrosis (RF) and RNPC at the basilar clivus is very difficult. This study was designed to investigate the characteristics of radiofibrosis and RNPC at the basilar clivus on dynamic enhanced magnetic resonance imaging (DMRI) for differential diagnosis. METHODS: A total of 38 NPC patients, treated in Cancer Center and the Second Affiliated Hospital of Sun Yat-sen University with follow-up of 1-5 years, were divided into 2 groups: 22 in RF group and 16 in RNPC (RNPC at the basilar clivus) group. After conventional plain MRI scan of nasopharynx, DMRI and conventional contrast enhanced T(1)-weighted imaging (T1WI) were performed. Maximal contrast enhancement ratio (MCER), time to MCER (Tmax), and contrast enhancement ratio at the 40th second of DMRI (CER(40s)) of basilar clivus, condylar process, and nasal concha were measured. RESULTS: The MCER and CER(40s) of RF at the basilar clivus were lower, and the Tmax was longer than those of RNPC at the basilar clivus. When CER40s > or =150%, CER40s of basilar clivus > or = CER(40s) of nasal concha, and the combination of these 2 indexes were respectively set as the DMRI diagnostic criteria of RNPC at the basilar clivus, the diagnostic sensitivity of the second criterion was the highest (81.3%), and the diagnostic specificity of the third criterion was also the highest (86.4%). CONCLUSIONS: DMRI is helpful for differential diagnosis of radiofibrosis and RNPC at the basilar clivus. RNPC at the basilar clivus is highly suggested when it meet the criteria of both CER(40s) > or =150% and CER(40s) of basilar clivus > or = CER(40s) of nasal concha. When the 2 criteria are conflictive, the latter is more accurate, MCER and Tmax of the basilar clivus should be took into consideration.

[Correlation of MR imaging features and histopathology of synovial sarcoma].

BACKGROUND & OBJECTIVE: Magnetic resonance imaging (MRI) is the best detective technique for soft tissue tumors, but it lacks specific imaging signs to distinguish various tumors. The synovial sarcoma is observed more frequently in soft tissue tumors. This study was to evaluate correlation of MRI features and histopathology of synovial sarcoma, and to improve the diagnostic accuracy of synovial sarcoma by MRI. METHODS: Twelve patients with synovial sarcomas were confirmed by operation and histopathology, included 9 men, and 3 women, aged from 35 to 50 years. Ten tumors located in lower limbs, 2 located in upper limbs. MRI was performed with a 0.5T magnet system. All images were obtained through T1-weighted imaging (T(1)WI), and T(2)-weighted imaging (T(2)WI), and some images were obtained by T(2)WI with stair. All patients received enhanced scan after Gd-DTPA injection. Radiological and histopathologic findings were compared. RESULTS: All tumors located in the places closed to joints, 2 invaded into joints, 3 invaded into bones. On T(1)WI, 12 tumors displayed signal intensity similar to that of skeletal muscle, and 3 showed cystic high intensity areas similar to that of subcutaneous fat. On T(2)WI, 6 tumors showed hyper-, iso-, and hypointense areas relative to fat constituting a triple signal intensity; 6 were multilocular, 3 were irregular, 3 were circular or elliptical. The septa configurations were seen in 5 tumors, fluid-fluid level sign was seen in 1 tumor. Maximum diameters of tumors ranged from 3 to 13 cm. All tumors enhanced asymmetrically after Gd-DTPA injection. On histological examination, 7 were poorly differentiated monophasic type, 3 were well differentiated monophasic type, 2 were biphasic type, 6 had old and/or fresh hemorrhage, 5 had large necrosis areas, 2 had calcification. CONCLUSION: MRI manifestation is specific in synovial sarcoma, and may be correlated with histopathology of synovial sarcoma.

[MRI performance and diagnosis of meningioma--a report of 126 cases].

BACKGROUND & OBJECTIVE: In MRI study of meningioma, it was lack of large group of patients to evaluate MRI qualitative diagnosis, and no consensus had been achieved concerning problems such as peritumoral edema in meningioma. This study was to summarize main clues for diagnosing meningioma through analyzing MRI performance of 126 patients with meningioma. METHODS: Among 126 patients with meningioma, 32 were syncytial, 35 were fibroblastic, 24 were psammomatous, 9 were angioblastic, 18 were transitional, 3 were papillary, and 5 were malignant. All patients were scanned with T1, T2-weighted imaging (T1WI, T2WI), and contrast-enhanced T1WI. RESULTS: Convexity of brain was more likely to be involved, among 126 cases of meningioma, 45 (35.7%) tumors located at convexity of brain. The size of tumor ranged from 1.4 to 9.9 cm. Eighty-one percent of tumors were round or oval in shape. Isointensity or slight hyperintensity of T2WI signals detected in 70.6% patients. The rates of tail sign, and pseudo-capsule were 62.7%, and 49.2%. Extruding sign of brain parenchyma was observed in 83.8% (57/68)of patients with tumor size of > 4 cm. Significantly even and increasing sign in contrast-enhanced T1WI were observed in 104 patients (82.5%). Peritumoral edema occurred in 57 patients (45.1%), and related to tumor size. Other rare signs included cystic changes, bleeding, calcification, osteal changes, and introtumoral vessel symptoms. The correct rate of diagnosis was 95.2%. CONCLUSIONS: MRI performances of meningioma are various. Judgment of extra-brain tumor, typical T2WI signals, tail sign, and significantly even and increasing sign are key factors for diagnosing meningioma.

[Diagnostic value of MR diffusion tensor imaging on radiation-induced early brain injury of nasopharyngeal carcinoma after radiotherapy].

BACKGROUND & OBJECTIVE: MR diffusion tensor imaging (DTI), a new MRI technique, can observe water molecule diffusion non-invasively at molecular level. This study was to assess diagnostic value of DTI on post-radiotherapy brain injury by quantitatively analyzing diffuse features of water in bilateral temporal lobes alba of those nasopharyngeal carcinoma (NPC) patients with normal conventional MRI performances. METHODS: DTI was performed in 13 NPC patients with normal conventional MRI performances after radiotherapy, and 21 healthy controls. Isotropic apparent diffusion coefficient (ADCiso) and anisotropic index (AI) were measured in bilateral temporal lobes alba. RESULTS: ADCiso of patient group was (631.30+/-27.83) x 10(-6) mm2/s, while that of control group was (651.76+/-39.10) x 10(-6) mm2/s (P>0.05). Temporal lobes diffusion AI decreased significantly in patient group, mean fractional anisotropy (FA) was 0.405+/-0.042, mean relative anisotropy (RA) was 0.355+/-0.044, and mean 1 minus volume ratio (1-VR) was 0.192+/-0.042; while those in control group were 0.463+/-0.047, 0.418+/-0.052, and 0.257+/-0.055, respectively (P< 0.01). CONCLUSIONS: DTI can early detect subtle alba changes in NPC patients after radiotherapy, which conventional MRI failed to sense. AI is more sensitive than ADCiso, may better describe the diffuse features of water molecules, and evaluate the temporal lobes alba changes before and after NPC radiotherapy.

[Preliminary study of astrocytic tumors by diffusion tensor imaging].

BACKGROUND & OBJECTIVE: Diffusion tensor imaging (DTI) is an advanced quantitative form of diffusion-weighted imaging. It could be used to calculate not only the apparent diffusion coefficient (ADC) of average water diffusion for each vowel, but also the diffusion anisotropic index of diffusion. Diffusion-weighted imaging is used in most of the studies of the brain tumors abroad. We used DTI method to measure the ADC, fractional anisotropy (FA) and relative anisotropy (RA), values of different tumor tissues and to evaluate the usefulness of ADC, FA, and RA in differentiating solid tumor, necrotic region, edema region, normal brain tissue, and in grading the malignancy of cerebral astrocytomas. METHODS: Fourteen cases of astrocytomas diagnosed (10 cases of grade 1-2 astrocytomas and 4 cases of grade 3-4 astrocytomas) were studied by DTI. ADC, FA, and RA values of different tumor tissue were measured. RESULTS: When all cases were analyzed as a group, significant differences of ADC were found in enhancing solid tumor (1.14+/-0.13x10(-3) mm(2)/s), necrotic region (2.04+/-0.50x10(-3) mm(2)/s), edema region (1.55+/-0.19x10(-3) mm(2)/s) compared with normal brain tissue (0.74+/-0.08x10(-3) mm(2)/s)(P< 0.05). Significant differences of ADC were also found in solid tumor (enhancing tissue:1.14+/-0.13x10(-3) mm(2)/s, non-enhancing tissue:1.01+/-0.25x10(-3) mm(2)/s) compared with necrotic region and edema region, respectively (P< 0.05). Significant differences of FA and RA were found in solid enhancing region (FA:0.21+/-0.08; RA:0.23+/-0.07), necrotic region (FA: 0.14+/-0.06, RA: 0.16+/-0.07), edema region (FA:0.16+/-0.04, RA:0.16+/-0.02) compared with normal brain tissue (FA: 0.37+/-0.06, RA: 0.38+/-0.07) (P< 0.05). No difference of FA and RA was found in solid tumor (including enhancing and non-enhancing tissue). Significant differences of ADC (P< 0.05), not FA and RA, were found between grade 1-2 astrocytomas (1.07+/-0.04x10(-3) mm(2)/s) and grade 3-4 astrocytomas (1.32+/-0.08x10(-3) mm(2)/s). CONCLUSION: Determination of ADC can be used to differentiate normal brain tissue from enhancing solid tumor, necrotic region, and edema region. Determination of FA and RA can be used to differentiate solid enhancing tumor, necrotic region, and edema region from normal brain tissue, but can not be used to differentiate solid tumor, necrotic region, and edema region. The ADC values, not FA and RA, may predict the degree of malignancy of astrocytic tumors.