Combine contrast-enhanced 3D T2-weighted short inversion time inversion recovery MR neurography with MR angiography at 1.5 T in the assessment of brachial plexopathy.

PURPOSE: To explore the benefits of using a single injection of contrast agent at a 1.5 T system to perform both contrast-enhanced MR angiography (MRA) and 3D-T2-STIR MR neurography (MRN) to assess of brachial plexopathy. METHODS: In this prospective study, 27 patients with suspected brachial plexopathy, received an imaging procedure composed sequentially of non-enhanced 3D-T2-STIR, CE-MRA, and contrast-enhanced 3D-T2-STIR, using a 1.5 T MR scanner. Signal intensities and contrast ratios were compared with and without contrast agent. The non-enhanced and contrast-enhanced 3D-T2-STIR images were mixed for two experienced radiologists to rate image diagnostic quality in a blind manner. 3D images of MRN and MRA were merged to reveal the spatial relation between brachial plexopathy and concomitant vascular disorders. RESULTS: By comparing the non-enhanced with contrast-enhanced 3D-T2-STIR images, it revealed that the use of the contrast agent in 3D-T2-STIR MRN could significantly suppress the background signals contributed by small vein (P < 0.001), lymph node (P < 0.001), muscle (P < 0.001) and bone (P < 0.001). This improved the contrast ratios between the brachial plexus and its surrounding tissues (P < 0.001) and boosted the image's quality score (P < 0.01). Examining both CE-MRA and 3D-T2-STIR images revealed a relatively high incidence of concurrent vascular dysfunction in brachial plexopathy, with 39% of confirmed cases accompanied with subclavian and axillary vessel abnormalities. CONCLUSION: Combining contrast-enhanced 3D-T2-STIR MRN with MRA at a 1.5 T system significantly suppresses background signals, improves brachial-plexus display, and provides a direct assessment for both brachial plexus lesion and surrounding vascular injury.

A Novel Approach for Imaging of Thoracic Outlet Syndrome Using Contrast-Enhanced Magnetic Resonance Angiography (CE-MRA), Short Inversion Time Inversion Recovery Sampling Perfection with Application-Optimized Contrasts Using Different Flip Angle Evolutions (T2-STIR-SPACE), and Volumetric Interpolated Breath-Hold Examination (VIBE).

BACKGROUND The aim of this study was to introduce a novel method combining contrast-enhanced magnetic resonance angiography (CE-MRA), short inversion time inversion recovery sampling perfection with application-optimized contrasts using different flip angle evolutions (T2-STIR-SPACE) and volumetric interpolated breath-hold examination (VIBE) sequences in the assessment of thoracic outlet syndrome (TOS). MATERIAL AND METHODS CE-MRA, T2-STIR-SPACE, and VIBE techniques were employed to evaluate neurovascular bundles in 27 patients clinically suspected of TOS. Images were evaluated to determine the cause of neurovascular bundle compression. Surgical exploration was performed in patients with abnormal magnetic resonance imaging (MRI) results. RESULTS Twenty patients were found to be abnormal: 6 cases showed only neurogenic TOS and the correlates included infraclavicular hemangiomas (n=1) and transverse cervical artery (n=5). Arterial-neurogenic TOS was found in 4 cases, including subclavian lymph node metastasis from breast cancer (n=3) and schwannoma (n=1). Arterial-venous-neurogenic TOS was found in 1 subject, and the correlates included a fibrous band from the cervical rib and elongated C7 transverse process. In this case, the subclavian artery/vein was compressed dynamically. Venous-neurogenic TOS was noted in one subject. Nine patients were considered as post-traumatic TOS, including brachial plexus edema (n=3), the brachial plexus rupture (n=2), peri-brachial plexus effusion (n=3), and stenosis of the SCA (n=1). In the remaining 7 patients, MRI did not detect abnormalities. CONCLUSIONS TOS can be evaluated by CE-MRA, T2-STIR-SPACE, and VIBE during a single examination, with a reduced contrast material dose. This imaging modality performs well in showing the anatomical structure of the neurovascular bundle and the cause of the compression.

[Value of diffusion-weighted MRI in differentiation between benign and malignant polypoid gallbladder lesions].

OBJECTIVE: To evaluate the efficiency of diffusion-weighted MRI in differentiating between benign and malignant polypoid gallbladder lesions. METHODS: The study population consisted of 10 benign (5 polyps, 3 adenomyomatosis and 2 adenomas) and 13 malignant (all adenocarcinomas) polypoid gallbladder lesions treated in hospital from November 2007 to May 2014. DWI was evaluated by two observers. Qualitatively, the signal intensity of the lesions on DWI was visually evaluated and categorized as iso, high, or very high signal.Quantitatively, the ADC values of the lesions were measured from ADC maps. Statistical analysis was performed using a two-tailed Fisher's exact test and the Mann-Whitney test, respectively. The cut-off values were determined by receiver operating characteristic analysis. RESULTS: Qualitative analysis revealed a statistical difference (P=0.036). In the 10 benign lesions, three were categorized as iso, 5 as high, and 2 as very high signal.Four of the 13 malignant lesions were categorized as high, and the remaining 9 were categorized as very high signal. The mean ADC value of the malignant lesions [(1.13±0.28)×10(-3) mm2/s] was significantly lower than that of benign lesions [(2.22±0.42)×10(-3) mm2/s, P<0.01]. The cut-off value between cancer and the benign lesions was 1.5×10(-3) mm2/s, the sensitivity, specificity, and accuracy were 92%, 100% and 96%, respectively. CONCLUSION: Diffusion-weighted MRI may be useful in differentiating between benign and malignant polypoid gallbladder lesions.