[en] Objective: To explore the value of MRI and ³¹P MRS in differential diagnosis of bone and soft tissue tumors. Methods: MRI and ³¹P MRS were performed in 35 bone and soft tissue tumor patients and 16 healthy volunteers at 1.5 T. The areas under the peak of various metabolite in spectra were measured. The spectra were analyzed by taking peak areas relative to peak area of β-ATP and by calculating the pH from the Pi shift relative to PCr. Results: The differences of the size, signal intensity homogeneity, border and involvement of surround structure between benign and malignant lesions had no statistically significant differences (P>0.05). There was great overlap in the MR imaging characteristics of benign and malignant lesions. The mean peak area rations of PME/β-ATP, PDE/β-ATP, LEP/β-ATP, PCr/β-ATP, intracellular pH in control group were 0.33±0.21, 0.64±0.27, 1.62±0.67, 3.12±0.78, 7.08±0.16. The mean peak area rations of PME/β-ATP, PDE/β-ATP, LEP/β-ATP, PCr/β-ATP, intracellular pH in benign group were 0.55±0.31, 0.81±0.31, 2.03±0.87, 1.65±0.65, 7.18±0.23. The mean peak area rations of PME/β-ATP, PDE/β-ATP, LEP/β-ATP, PCr/β-ATP, intracellular pH in malignant group were 1.73±0.40, 1.73±0.45, 4.31±1.18, 1.44±0.54, 7.32±0.29. Compared with control group, the mean peak area rations of PME/β-ATP (P<0.01), PDE/β-ATP (P<0.01), LEP/β-ATP (P<0.01), intracellular pH(P<0.05) in malignant group increased significantly and PCr/β-ATP(P<0.01) in benign and malignant group decreased significantly. The mean peak area rations of PME/β-ATP, PDE/β-ATP, LEP/β-ATP and intracellular pH in benign group were higher than that of the normal group but did not reach statistical significance (P>0.05). The mean peak area rations of PME/β-ATP, PDE/β-ATP,LEP/β-ATP in malignant group were significantly higher than that in benign group (P<0.01). Intracellular pH in malignant group was higher than that in benign group but did not reach statistical significance (P>0.05). If we set a standard at 1.8 time of the mean of the PME/β-ATP ration in the benign group, then the sensitivity of this discrimination for diagnosing a malignancy was 88.89% and the specificity was 94.12%. Conclusion: ³¹P MRS has important value in diagnosis and differential diagnosis of bone and soft tissue tumors. It should be a simple, non-invasively, effective diagnostic method. (authors)

[en] Objective: To study the myocardial perfusion in acute myocardial infarction by using Multislice spiral CT (MSCT), and to explore the value of MSCT coronary angiography in showing the coronary artery blockage. Methods: The left anterior descending artery (LAD) was ligated in nine healthy dogs. Then MSCT perfusion scans were done in several stages (pre-ligation, 30 min,1, 2, 4, 6, and 8 h post-ligation). The perfusion peculiarity was analyzed and compared with pathological findings. MSCT coronary angiography was done before and after LAD ligation. Results: The mean normal myocardial perfusion was (69.3 ± 13.9) ml·100 g^-1·min^-1. The mean time to peak (TTP) was (12.8 ± 2.1) s. 30 min after LAD was ligated, the myocardial perfusion was (25.2 ± 3.4) ml·100 g^-·min^-1. It became significantly lower than normal, and time-density curve got flat. There was no significant difference between the density of normal myocardium (44.9 ± 22.0) HU and that of LAD ligation areas on 10 min delay scan (67.1 ± 11.4) HU (P>0.05). But significant enhancement was found after LAD ligation for 4 hours (82.1±15.2) HU. MSCT coronary angiography could show the blockage of LAD in nine dogs. Conclusion: MSCT myocardial perfusion combined with coronary angiography could estimate myocardial ischemia and infarction, and show the blockage of the coronary artery

[en] Objective: To evaluate the relationship between Multi-slices spiral (MSCT) perfusion and micro vessel density (MVD) in maxillofacial tumors. Methods: Thirty-one cases of maxillofacial tumors were studied with MSCT perfusion imaging before operation. The time-density curve, perfusion, time to peak (TTP), and Peak enhancement imaging (PEI) of tumors were calculated. MVD of the tumors was measured with immuno-histochemical method by means of detecting factor VIII in all the histologic specimens. Relativity analysis was carried between MSCT perfusion imaging parameters, perfusion curve types and MVD. Results: MVD of maxillofacial tumors were higher than normal tissue. MVD remarkably correlated with malignancy of the tumors. Perfusion and time to peak (TTP) correlated well with MVD (t=7.09, 4.10, P<0.05), but peak enhancement imaging (PEI) did not (t=0.76, P>0.05). Significant difference of MVD in three types of perfusion curve was found (F=8.09, P<0.05). The tumors in the rapid ascend style had the highest MVD. Conclusion: There are close correlations between MVD and perfusion, time to peak (TTP) and the shape of perfusion curve. MSCT perfusion imaging might evaluate MVD of maxillofacial tumors. It is a useful method in estimating the degree of angiogenesis and prognosis of maxillofacial tumors.(authors)

[en] Objective: To investigate the usefulness of 3 T MRI 3D-FIESTA in the evaluation of the intraparotid components of the facial nerve and parotid duct, and compare them with surgical findings. Methods: Twenty-two cases with parotid benign tumors were scanned with conventional and 3D-FIESTA sequences on 3 T MRI scanner. Postprocessed multiplanar images were obtained with the workstation. Parotid ducts and facial nerves and tumors were identified on these images. The relationship of the tumors to the facial nerves and Parotid ducts was confirmed at surgery. Results: Various types of parotid benign tumors had their characteristics on 3 T MR imaging. Parotid benign tumors mainly showed hypo-intensity on T₁WI in 21 cases, and hyper-intensity on T₂WI in 22 cases. But on 3D-FIESTA images, they appeared hypointensity (10 cases) or high intensity (12 cases) due to different types. Facial nerves in parotid appeared as linear structures with hypo-inteusity. The indication of the main trunks were 16 and 18 cases for T₁WI and T₂WI images, while on 3D-FIESTA images, the main trunks and cervicofacial and temporofacial divisions of the facial nerves were found in 22, 21,22 cases. Parotid ducts appeared as structures with hypo-intensity on T₁WI and hyper-intensity on multiplanar images (14, 20, 22 cases). Compared with surgical results, the main trunks of the facial nerve were correctly showed by 3D-FIESTA images in 20 cases. However, in 2 cases they were not located in the operation because of shifting. Conclusion: 3 T MR 3D-FIESTA imaging could depict the extracranial facial nerve and the parotid duct in the parotid gland, which is useful for preoperative evaluation of parotid gland tumors. (authors)

[en] Objective: To evaluate the value of intratumoral vessels and micro-hemorrhage shown in susceptibility weighted imaging (SWI) for grading brain astrocytomas and to analyze the difference between SWI and conventional imaging techniques. Methods: 22 patients with astrocytomas were diagnosed with surgical specimens, 9 of which were grades I-II, and 13 were grades III-IV. All examinations were performed on Signa DEx 3.0 T MRI scanner. Conventional imaging techniques (T1WI, T2WI, T2FLAIR, CE-T1WI) and SWI sequence were used. The parameters of SWI sequence were the following: TR = 35 ms, TE = 20 ms, FA = 15^o, slice thickness = 2 mm. The small vessels and blood products of the tumors in SW images were analyzed. The differences between the two groups in SW images were analyzed statistically. Results: The findings in SW images of brain astrocytomas were correlated strongly with pathology. SWI was more sensitive compared to conventional imaging techniques for showing small vessels and micro-hemorrhage in brain astrocytomas. Statistical comparison showed that the small vessels and micro-hemorrhage of two groups of brain astrocytomas in SW images differed significantly. Conclusion: SWI is superior to conventional imaging techniques at showing the small vessels and micro-hemorrhage in brain astrocytomas, which plays an important role in the tumor grading.

[en] Objective: To investigate the spatial relationship between intraparotid facial nerve and parotid ducts in different types of parotid neoplasms with 3D improved motion-sensitized driven-equilibrium pulse (3D-iMSDE) MR neurography, and to guide the operation plan. Methods: By means of prospective research methods, the sequences of 3D-iMSDE and 3D-T₂-fast field echo (3D-T2-FFE) were obtained in 30 healthy volunteers and 40 patients with parotid gland tumors, respectively. All patients with parotid mass were found by physical examination, by maxillofacial surgeons or by ultrasonography or other imaging examinations. Facial nerve trunk with its first branches and parotid ducts were evaluated independently on images of iMSDE and T₂-FFE sequence for volunteers. The signal intensity ratio (SIR) of both facial nerve and parotid ducts were compared respectively in two sequences The relationship between intraparotid facial nerve and parotid ducts with the lesion were analyzed on images of iMSDE and T₂-FFE sequences for 40 patients. The results were compared with intra-operative anatomy and post-operative pathological findings. Wilcoxon symbolic rank test, t test and chi-square test were used Results: The image scores of intra-parotid facial nerve and parotid ducts in iMSDE sequence were higher than that of T₂-FFE sequence in all 30 healthy volunteers. The difference was statistically significant (Z = -6.197, P < 0.05). Both the facial nerve and parotid duct on images of iMSDE sequence had higher SIR than that of T₂-FFE. The differences were statistically significant (t = 10.772, 11.586, respectively; P < 0.05). Forty patients with parotid gland tumors had a total of 41 lesions. Compared with the intraoperative anatomy, the accuracy of iMSDE and T₂-FFE sequences in showing the relationship between the facial nerve and its primary branches with the mass were 36/41 (87.8%), and 22/41 (53.7%) respectively, and the accuracy of the two sequences in showing the relationship between the dominant duct of the parotid gland and the mass were 38/41 (92.7%) and 30/41 (73.2%), respectively. The accuracy rate in showing the relationship between facial nerve and its primary branch and the mass on images of iMSDE sequence were higher than that of T₂-FFE sequence, and also in showing the relationship of parotid duct and the mass. The statistical differences were significant (x² = 9.725, 5.513; P < 0.05, respectively). In the iMSDE sequence, the relationship between the facial nerve and its first branches (temporofacial and cervicofacial division) with the tumor was correctly demonstrated in 36 cases. 38 cases of parotid ducts were satisfactorily displayed on image of iMSDE sequence. Conclusions: The 3D-iMSDE MRN sequence can correctly show the relationship between intraparotid facial nerve and parotid duct and the parotid gland neoplasms. (authors)

[en] Aim: To investigate the usefulness of three-dimensional (3D) fast imaging employing steady state precession (FIESTA) magnetic resonance imaging (MRI) at 3 T in evaluating the intraparotid components of the facial nerve and parotid ducts, and to compare the MRI images with surgical findings. Materials and methods: Thirty-one cases of benign parotid tumours were studied with conventional and 3D FIESTA MRI sequences at 3T using a head coil. The most clinically useful 3D FIESTA images were acquired at parameters of 4.9 ms repetition time (TR); 1.5 effective echo time (TEeff); a flip of 55°, a field of view of 18 to 20 cm, a matrix of 512 × 320, an axial plane, no gaps, and a section thickness of 1 mm. Post-processed multiplanar images were obtained with an Advantage Windows (AW sdc 4.3) workstation. Parotid ducts, facial nerves, and tumours were identified on these images. The relationship of the tumours to the facial nerves and parotid ducts was confirmed at surgery. Results: The facial nerves appeared as linear structures of low intensity. The main trunk of the facial nerve was identified bilaterally in 93.5% of the 3D-FIESTA sequence images. Parotid ducts appeared as structures of high intensity on multiplanar 3D-FIESTA images (100%). The relationships of the tumours with the cervicofacial and temporofacial divisions of the facial nerve were correctly diagnosed in 26 of 31 cases (83.9%) using 3D-FIESTA sequence images. Conclusion: 3D-FIESTA MRI at 3 T depicted the main trunk, cervicofacial and temporofacial divisions of the facial nerve, and the main parotid duct. It is useful for preoperative evaluation of parotid gland tumours.

[en] To use three-dimensional real inversion recovery (3D-real IR) MRI to investigate correlations between endolymphatic hydrops (EH) grades or the degree of perilymphatic enhancement (PE) and clinical features of Ménière's disease (MD), as previous findings have been inconsistent. A total of 273 consecutive patients with definite unilateral MD were retrospectively enrolled from September 2020 to October 2021. All patients underwent 3D-real IR and 3D-T2WI 6 h after intravenous gadolinium injection. MD-related symptom duration and vertigo frequency were recorded. EH grades were evaluated, the signal intensity ratio (SIR) was measured, and correlations between clinical features and EH, PE were assessed respectively. The study included 123 males and 150 females, with a mean age of 53.0 years. A longer duration of vertigo was associated with higher cochlear EH grades, whereas the opposite was true for the duration of aural fullness. A longer time since vertigo onset was associated with higher vestibular EH grades; the opposite was true for the duration of individual vertigo attacks. The multiple regression analysis revealed that age, tinnitus duration, and vestibular EH were risk factors for SIR. Furthermore, the low-frequency hearing threshold (HT) was a risk factor for cochlear and vestibular EH, and the SIR. The EH grade and SIR (an indicator for the quantitative evaluation of PE) were correlated with clinical features and HT of MD; thus, imaging can be a valuable tool in planning individualised treatment. This study revealed that the grade of endolymphatic hydrops and degree of perilymphatic enhancement positively correlates with the length of time since onset of clinical symptoms and hearing thresholds in patients with Ménière's disease, facilitating the tailored treatment.

[en] This study aimed to investigate the feasibility of segmentation-independent volume rendering (SI-VR) in visualising the root entry zone (REZ), and to explore the influence on the management of vascular compression syndromes (VCSs). Two hundred and twenty patients with VCSs were recruited in this prospective study from July 2015 to May 2019. SI-VR was reconstructed based on inverted 3D fast spin echo T2WI. They were assigned to the experimental group and control group randomly. Patients in the experimental group would accept extra evaluation based on SI-VR before microvascular decompression. Image quality and diagnostic accuracy between SI-VR and 3D fast spin echo T2WI in the experimental group were compared by Mann-Whitney U test and chi-square test, separately. Interobserver agreement was performed with intraclass correlation coefficient. Postsurgical outcomes and complications between two groups were compared by chi-square test. SI-VR had a better interobserver agreement (0.82 vs 0.68) and diagnostic accuracy (95.5% vs 83.6%, p = 0.004) than that of 3D fast spin echo T2WI. Especially, significantly improved diagnostic accuracy was reached in detecting the multi-vascular branches compression (100% vs 15.4%, p < 0.001). There were fewer complications (7.1% vs 26.8%, p = 0.004) and less operation time (20.7 min vs 14.5 min, p = 0.007) but no significant difference of pain relief (p = 0.19) in the experimental group than in the control group. The SI-VR method is feasible for the precise demonstration of the anatomy structure along the REZ, with high reliability and reproducibility. Unbiased pre-surgical visualisation could reduce redundant explorations and post-surgical complications in patients who undergo microvascular decompression.

[en] To determine whether magnetic resonance imaging (MRI) can improve diagnostic accuracy for definite and probable Ménière's disease (MD) based on perilymphatic enhancement (PE) and endolymphatic hydrops (EH). 363 patients with unilateral MD (probable MD, n = 75 and definite MD, n = 288) were recruited. A three-dimensional zoomed imaging technique with parallel transmission SPACE real inversion recovery was performed 6 h after intravenous gadolinium injection to investigate the presence of PE and to evaluate the grading and location of EH. PE and EH characteristics were analyzed and compared between the probable and definite MD groups. The cochlear and vestibular EH grading on the affected side was more severe in the definite MD group than that in the probable MD group (P < 0.001). The EH locations within the inner ear on the affected side also differed between the two groups (χ${}^2$ = 81.15, P < 0.001). The signal intensity ratio (SIR) on the affected side was significantly higher in the definite MD group than in the probable MD group (t = 2.18, P < 0.05). The assessment of the combination of PE and EH parameters within the inner ear revealed a higher area under the curve (AUC) in the definite MD group (0.82) compared with the AUCs of the parameters assessed alone. The assessment of a combination of PE and EH parameters improved the diagnostic accuracy for probable and definite MD, suggesting that MRI findings may be clinically useful in the diagnosis of MD.