Magnetic Resonance Imaging Anatomy of Alar Ligament: A Review of Literature

@#Alar ligament is one of the most important craniocervical junction (CCJ) ligaments; acting as stabilizer of CCJ and limiting axial rotation. It may be involved in various pathological processes including trauma. Magnetic resonance imaging (MRI) is increasingly being used in cervical spine trauma as a supplement to conventional radiography and computed tomography (CT) to detect a wide range of severe cervical spine injuries. MR depiction of alar ligament requires special sequences despite no known established MR sequence is available. However, the role of MRI in minor or moderate trauma, including whiplash injuries, has long been debated, particularly when neurological dysfunction is absent, because no anatomical disruption other than degenerative disc disease have been reported. In this review, we provide detailed account on the current knowledge of MR visualization of normal alar ligament; outlining the variations in its signal intensity, dimension, shape and orientation.

Clinical value of 3.0T magnetic resonance magnetic sensitive weighted imaging in the diagnosis of neonatal hypoxic ischemic encephalopathy / 中国基层医药

Objective To explore the clinical value of 3.0T nuclear magnetic resonance susceptibility weighted imaging in diagnosis of neonatal hypoxic ischemic encephalopathy,thus to provide guidance for the clinical.Methods From December 10,2015 to December 10,2017,100 cases of neonatal hypoxic ischemic encephalopathy (observation group) and 100 cases of normal newborns in Lishui People's Hospital during the same period accepted health examination (control group) were selected in the research.All the cases received 3.0T magnetic resonance susceptibility weighted imaging,the diagnostic value of 3.0T MR susceptibility weighted imaging was observed.Results The ADC value of the observation group[(0.00 1 13 ± 0.000 01)mm2/s] was significantly lower than that in the control group[(0.001 98 ±0.000 02)mm2/s] (P ＜0.05).The neonatal ADC value of the mild group[(0.001 21 ± 0.000 01)mm2/s] was significantly higher than that in the moderate group[(0.001 12 ± 0.000 02)mm2/s] and the severe group[(0.001 02 ± 0.000 03)mm2/s] (P ＜ 0.05).ADC value was positively correlated with neonatal hypoxic ischemic encephalopathy,namely,the lower the ADC value,the more serious the neonatal hypoxic ischemic encephalopathy.The fractional anisotropy value and relative anisotropy value of newborn babies in the observation group were significantly higher than those in the control group (all P ＜ 0.05).Conclusion For neonatal hypoxic ischemic encephalopathy patients,3.0T nuclear magnetic resonance susceptibility weighted imaging in the diagnosis is feasible,it can help the clinician to analyze the disease,and has positive significance to carry out the treatment.

Clinical value of 3.0T MRI for hilarcholangiocarcinoma diagnosis / 医疗卫生装备

Objective To investigate the clinical value of 3.0T MRI for hilarcholangioc-arcinoma diagnosis.Methods T Totally48 hilarcholangiocarcinoma patients from October 2011 to June 2015 underwent diagnoses by 3.0T MRI and 64-slice spiral CT,and then the diagnosing results were compared with those by surgery and pathological examination to determine the value of 3.0T MRI for hilarcholangiocarcinoma diagnosis.Results 3.0T MRI had the positioning accuracy (100％) and qualitative accuracy (95.83％) significantly higher than the positioning accuracy (79.17％) and qualitative accuracy (81.25％) (P＜0.05).In case of hepatic duct dilatation,CT found 35 cases of hilar masses,14 cases of lymphoma,5 cases of hepatic duct wall invasion and 9 cases of portal vein invasion,while 3.0T MRI displayed 44 cases of hilar masses,26 cases of lymphoma,13 cases of hepatic duct wall invasion and 30 cases of portal vein invasion.Conclusion 3.0T MRI has high positioning and qualitative accuracies when used to diagnosing hilarcholangiocarcinoma,behaves well in displaying hepatic duct dilatation,high resolution of soft tissues,and thus is worthy promoting clinically.

Intra-Individual, Inter-Vendor Comparison of Diffusion-Weighted MR Imaging of Upper Abdominal Organs at 3.0 Tesla with an Emphasis on the Value of Normalization with the Spleen

OBJECTIVE: To compare the apparent diffusion coefficient (ADC) values of upper abdominal organs with 2 different 3.0 tesla MR systems and to investigate the usefulness of normalization using the spleen. MATERIALS AND METHODS: Forty-one patients were enrolled in this prospective study, of which, 35 patients (M:F, 27:8; mean age ± standard deviation, 62.3 ± 12.3 years) were finally analyzed. In addition to the routine liver MR protocol, single-shot spin-echo echo-planar diffusion-weighted imaging using b values of 0, 50, 400, and 800 s/mm2 in 2 different MR systems was performed. ADC values of the liver, spleen, pancreas, kidney and liver lesion (if present) were measured and analyzed. ADC values of the spleen were used for normalization. The Pearson correlation, Spearman correlation, paired sample t test, Wilcoxon signed rank test and Bland-Altman method were used for statistical analysis. RESULTS: For all anatomical regions and liver lesions, both non-normalized and normalized ADC values from 2 different MR systems showed significant correlations (r = 0.5196-0.8488). Non-normalized ADC values of both MR systems differed significantly in all anatomical regions and liver lesions (p < 0.001). However, the normalized ADC of all anatomical regions and liver lesions did not differ significantly (p = 0.065-0.661), with significantly lower coefficient of variance than that of non-normalized ADC (p < 0.009). CONCLUSION: Normalization of the abdominal ADC values using the spleen as a reference organ reduces differences between different MR systems, and could facilitate consistent use of ADC as an imaging biomarker for multi-center or longitudinal studies.

Influence of the 3.0T magnetic resonance on the hearing of newborn infants / 中华实用儿科临床杂志

Objective To evaluate whether or not the 3.0T magnetic resonance (MR) scanner noise has adverse influence on neonatal hearing by using brainstem auditory evoked potentials(BAEP).Methods Forty-nine inpatients who received the MR examination were enrolled in this study from Aug.to Dec.2013,admitted to the Bayi Children's Hospital Affiliated to Beijing Military General Hospital.The Ⅰ,Ⅲ,Ⅴ wave latencies and the inter-peak intervals before and after the MR scan were compared by using SPSS 16.0 software.Results The BAEP results before and after MR examination respectively:(1) The latencies were:left ear Ⅰ wave (1.96 ± 0.22) ms vs (1.95 ± 0.30) ms,right ear Ⅰ wave (1.96 ± 0.22) ms vs (1.97 ± 0.27) ms,respectively; left ear Ⅲ wave (4.79 ± 0.23) ms vs (4.85 ± 0.28) ms,right earlllwave(4.78 ±0.24) ms vs (4.77 ±0.31) ms,respectively;left ear Ⅴ wave (7.10 ±0.24) ms vs (7.12 ±0.33) ms,right ear Ⅴ wave (6.76 ±0.32) ms vs (7.04 ±0.39) ms,respectively(allP ＞0.05).(2) The inter-peak intervals were:left ear Ⅰ-Ⅲ inter-peak interval (2.83 ± 0.23) ms vs (2.86 ± 0.27) ms,right ear Ⅰ-Ⅲ inter-peak interval (2.82 ± 0.24) ms vs (2.80 ± 0.17) ms,respectively ; left ear Ⅲ-Ⅴ inter-peak interval (2.31 ±0.28) ms vs (2.31 ±0.29) ms,right ear Ⅲ-Ⅴ inter-peak interval (2.26 ±0.27) ms vs (2.26 ±0.23) ms,respectively;left ear Ⅰ-Ⅴ inter-peak interval (5.11 ±0.40) ms vs (5.13 ±0.35) ms,right ear Ⅰ-Ⅴ inter-peak interval (5.07 ± 0.39) ms vs (5.07 ± 0.36) ms,respectively(all P ＞ 0.05).Conclusion The 3.0T MR may have no adverse influence on neonatal BAEP.

Quantitative Analysis of the Facial Nerve Using Contrast-Enhanced Three Dimensional FLAIR-VISTA Imaging in Pediatric Bell's Palsy

PURPOSE: To evaluate the usefulness of quantitative analysis of the facial nerve using contrast-enhanced three-dimensional (CE 3D) fluid-attenuated inversion recovery-volume isotopic turbo spin echo acquisition (FLAIR-VISTA) for the diagnosis of Bell's palsy in pediatric patients. MATERIALS AND METHODS: Twelve patients (24 nerves) with unilateral acute facial nerve palsy underwent MRI from March 2014 through March 2015. The unaffected sides were included as a control group. First, for quantitative analysis, the signal intensity (SI) and relative SI (RSI) for canalicular, labyrinthine, geniculate ganglion, tympanic, and mastoid segments of the facial nerve on CE 3D FLAIR images were measured using regions of interest (ROI). Second, CE 3D FLAIR and CE T1-SE images were analyzed to compare their diagnostic performance by visual assessment (VA). The sensitivity, specificity, and accuracy of RSI measurement and VA were compared. RESULTS: The absolute SI of canalicular and mastoid segments and the sum of the five mean SI (total SI) were higher in the palsy group than in the control group, but with no significant differences. The RSI of the canalicular segment and the total SI were significantly correlated with the symptomatic side (P = 0.028 and 0.015). In 11/12 (91.6%) patients, the RSI of total SI resulted in accurate detection of the affected side. The sensitivity, specificity, and accuracy for detecting Bell's palsy were higher with RSI measurement than with VA of CE 3D FLAIR images, while those with VA of CE T1-SE images were higher than those with VA of CE 3D FLAIR images. CONCLUSION: Quantitative analysis of the facial nerve using CE 3D FLAIR imaging can be useful for increasing the diagnostic performance in children with Bell's palsy when difficult to diagnose using VA alone. With regard to VA, the diagnostic performance of CE T1-SE imaging is superior to that of CE 3D FLAIR imaging in children. Further studies including larger populations are necessary.

Comparison of human brain metabolite levels using 1H MRS at 1. 5T and 3. 0T / Comparação dos níveis de metabólitos cerebrais utilizando espectroscopia de prótons por ressonância magnética em 1. 5T e 3. 0T

Proton magnetic resonance spectroscopy (MRS) of the human brain has proven to be a useful technique in several neurological and psychiatric disorders and benefits from higher scanners as signal intensity and spectral resolution are proportional to the magnetic strength. OBJECTIVE: To investigate the effects of the magnetic on the measurement of brain metabolites in a typical routine clinical setting. METHODS: Single voxel spectra were acquired from the posterior cingulate cortex in 26 healthy subjects. Each subject was scanned consecutively at 1.5T and 3.0T in a randomly distributed order. RESULTS: SNR and peak width improvements were observed at higher s. However, SNR improvement was lower than the theoretical two-fold improvement. Other than the values obtained for creatine (Cre) and myo-Inositol (mI), which were both higher at 3.0T, all metabolite concentrations obtained were roughly the same at both strengths. All the metabolite concentrations were estimated with a Cramer Rao lower bounds (CRLB) lower than 15% of the calculated concentrations. CONCLUSIONS: Even though the present study supports the expected benefits of higher strength for MRS, there are several factors that can lead to different quantitative results when comparing 1.5T to 3.0T MRS. Future comparative studies are necessary to refine the metabolite thresholds for early detection and quantification of distinct neurological and psychiatric disorders using 3.0T MRS.

Espectroscopia de prótons por ressonância magnética (MRS) tem se mostrado uma técnica bastante útil em diversas doenças neurológicas e psiquiátricas. A utilização de sistemas de mais alto campo magnético favorece essa técnica uma vez que a intensidade do sinal e a resolução espectral são proporcionais à intensidade do campo. OBJETIVO: Avaliar o efeito do campo magnético sobre a medida dos níveis dos metabólitos cerebrais em uma típica rotina clínica. MÉTODOS: Os dados foram obtidos em 26 indivíduos saudáveis nos sistemas de 1.5T e 3.0T. As aquisições foram feitas sequencialmente e a ordem foi distribuida randomicamente.RESULTADOS: Foram observadas melhoras na relação sinal-ruído (SNR) e na largura de linha dos picos nos dados obtidos em campo maior. No entanto, a melhoria na SNR foi menor que o esperado teoricamente que seria o dobro da obtida em 1.5T. Exceto pelos valores obtidos para creatina e mio-inositol, que foram maiores em 3.0T, todas as concentrações de metabólitos obtidas foram aproximadamente a mesmo em ambos os campos. Todas as concentrações de metabólitos foram estimadas com Cramer Rao lower bounds (CRLB) inferior a 15% das concentrações calculadas. CONCLUSÕES: Apesar de o presente estudo dar suporte aos benefícios gerados pelo aumento do campo para a técnica de MRS, existem fatores que podem levar a diferentes resultados quantitativos quando se compara espectroscopia em 1.5T e 3.0T. Estudos comparativos serão necessários para refinar os limiares dos níveis de metabólitos para melhorar a acurácia da detecção de doenças neurológicas utilizando espectroscopia em 3.0T.

Clinical application value of 3.0 T MR susceptibility weighted imaging in diagnosis of neonatal hypoxic ischemic encephalopathy / 临床儿科杂志

Objective To evaluate the clinical application value of susceptibility weighted imaging (SWI) in neonatal hy-poxic ischemic encephalopathy (HIE). Methods Thirty-six neonates with HIE were collected and scanned by GE 3.0 T supercon-ducting MR scanner. Routine axial T1WI, T2WI, FLAIR scan and axial SWI scan were conducted. SWI sequence was compared with conventional head MRI sequences in detection rate of distribution and quantity of intracranial hemorrhage. Meanwhile, the display condition of the dilated cerebral deep veins and cortical veins was observed on SWI image and the performance of HIE in different clinical classification on SWI was compared. Results A total of 97 intracranial hemorrhages were detected by SWI in 27 cases. Only 41, 27 and 51 hemorrhages were found by TIWI, T2WI and FLAIR sequences, respectively. SWI were significantly superior to T1WI, T2WI and FLAIR in displaying the size, scope and boundary definition of hemorrhage. A total of 50 dilated ce-rebral deep veins and cortical veins were detected by SWI in 22 cases which were not found by conventional head sequences. The detection rates of intracranial hemorrhage and intracranial hemorrhage in addition of dilated cerebral veins on SWI sequence were the lowest in mild HIE group, and highest in severe group. There was significant difference among the mild, medium and severe groups (P<0.05). Conclusions SWI sequence has higher sensitivity than conventional MRI sequence in detecting intracranial hemorrhage and dilated vein in HIE, and is useful for early diagnosis of HIE.

Magnetic Field Interactions of Copper-Containing Intrauterine Devices in 3.0-Tesla Magnetic Resonance Imaging: In Vivo Study

OBJECTIVE: An ex vivo study found a copper-containing intrauterine device (IUD) to be safe for women undergoing an MRI examination at a 3.0-T field. No significant artifacts caused by the metallic implant were detected. However, there are still no in vivo data about these concerns. The aim of this study was to evaluate 3.0-T magnetic field interactions of copper-containing IUDs in vivo. MATERIALS AND METHODS: Magnetic field interactions and potential adverse events were evaluated in 33 women using a questionnaire-based telephone survey. Two experienced radiologists performed artifact evaluation on MR images of the pelvis. RESULTS: Eighteen patients were eligible for the survey. One patient reported a dislocation of the IUD after the MR examination. All other patients had no signs of field interactions. No IUD-related artifacts were found. CONCLUSION: MRI at 3.0-T is possible for women with copper-containing IUDs. However, consulting a gynecologist to check the correct position of the IUD and exclude complications after an MR examination is highly recommended. High-quality clinical imaging of the female pelvis can be performed without a loss in image quality.