Value of Reduced Field-of-view DWI in Quantitative Assessment of Axial Spondyloarthritis / 中山大学学报(医学科学版)

ObjectiveTo investigate the value of reduced field-of-view DWI （r-FOV DWI） in quantitative assessment of axial spondyloarthritis. MethodsA total of 112 patients with chronic back pain or suspected axial spondyloarthritis receiving full field-of-view DWI （f-FOV DWI） and reduced field-of-view DWI （r-FOV DWI） from December 2019 to December 2021 were enrolled. Next， subjective image quality assessment （anatomical detail， artifacts， distortion， overall image quality） and objective image quality assessment including （signal to noise ratio and contrast to noise ratio） were conducted by two experienced radiologists. In addition， the Apparent Diffusion Coefficient （ADC） values of three groups （active group， inactive group， and control group） on the two DWI sequences were measured by the two radiologists， respectively. Finally， the consistency of measurement between the two researchers was evaluated and the differences in ADC values was compared. Results102 patients were included and were divided into three groups， including the active group （n=32）， inactive group （n=29）， and control group （n=41） according to ASAS diagnostic criteria. All subjective and objective image quality metrics were rated in favor of r-FOV DWI images compared with f-FOV DWI images ［overall image quality： DWI 4（3~4） vs. 3（3~3） and SNR： 6.58（5.05~10.38） vs. 4.46（2.37~10.04）， CNR： 2.04（-1.14~8.29） vs. 0.97（-8.19~7.12）；P＜0.05］. Inter-rater consistency of the two researchers were 0.60~0.74. According to the AUC curve， group inactive vs. control showed r-FOV DWI was better than f-FOV DWI. In other groups （lesion vs. control， active vs. inactive）， there were no differences between both sequences（P＜0.05）. ConclusionThe subjective image quality score and signal to noise ratio of r-FOV DWI were higher than those of f-FOV DWI， which could be used for quantitative assessment of axial spondyloarthritis.

Application of cone beam computed tomography in the diagnosis of root fractures / 口腔疾病防治

@#Cone beam computed tomography (CBCT) has been widely used in various fields of dentistry. The diagnosis of root fractures, especially vertical root fractures (VRFs) with CBCT images, has been a research hotspot since then. Research on this area mainly includes the following five aspects: ① the diagnostic efficiency of CBCT images for root fractures; ② the influence of scanning parameters on the diagnostic accuracy of CBCT images in root fractures, such as scanning field of view, spatial resolution, tube current and tube voltage; ③ whether the application of image postprocessing techniques, especially metal artifact reduction (MAR), can improve the diagnostic accuracy of root fractures after root canal treatment and/or there is a post core in the root canal; ④ establishment and validation of clinical diagnosis model for vertical root fracture; and ⑤ application of artificial intelligence technology and contrast agent in root canals for the diagnosis of CBCT image in root fractures. Compared with periapical radiographs, CBCT images can improve the diagnostic accuracy of root fractures in nonendodontic treated teeth; however, for teeth that have undergone endodontic treatment, the diagnosis of VRF must be combined with clinical signs. Vertical bone resorption in the buccolingual (palatal) direction is a characteristic indicator of VRF. The width of the VRF is an important factor affecting the diagnostic accuracy, but the voxel size used in CBCT scanning is not a necessary factor affecting its diagnostic accuracy; the fracture direction does not affect the diagnostic accuracy of the VRF. Image postprocessing techniques, especially MAR, cannot improve the diagnostic accuracy of VRF and may also reduce the diagnostic efficiency, so they are not recommended for clinical application.

Objective Assessment of Visual Field Defects Caused by Optic Chiasm and Its Posterior Visual Pathway Injury / 法医学杂志

OBJECTIVES@#To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury.@*METHODS@#Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential (VEP) and multifocal visual evolved potential (mfVEP) measurements, craniocerebral CT/MRI, and retinal optical coherence tomography (OCT) were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively.@*RESULTS@#The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder (RAPD) and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway.@*CONCLUSIONS@#Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.

Optimization of parallel acquisition technique in 3D TOF MRA of head with 8-receiving channels phased-array coil in 1.5T MR system: A phantom study / 中国医学影像技术

Objective: To explore the application value of array spatial sensitivity encoding technique (ASSET) in 3D TOF MRA of head with 8-receiving channels phased-array coil in 1.5T MR system and the methods to eliminate image artifact, in order to optimize the scanning protocol of 3D TOF MRA. Methods Using the standard model of head for MRI, scanning of 3D TOF MRA was performed combining with different ASSET reduce factor (R value), phase FOV (FOVp), scanning FOV (FOVs) and calibration FOV (FOVc; 30 cm×30 cm in group A, 35 cm×35 cm in group B and 40 cm×40 cm in group C). Then the shortest distance between bilateral wrapped artifacts (D) and SNR was measured, and the acquisition time (TA) of each group and resolution on phase direction (Rp) were recorded. Then the optimized parameters were estimated. Results ASSET artifact became serious as FOVc increased, the distance between wrapped artifact broadened to disappear as FOVs and FOVp increased and R value decreased. TA unchanged as R value and FOVp unchanged. When R value fixed, SNR increased as FOVs and FOVp increased. SNR decreased as R value increased when FOVs and FOVp fixed. Rp decreased as FOVs and FOVp increased. Conclusion ASSET scanning needs right R value matching with corresponding FOVc, FOVs and FOVp. The optimization parameters under the above mentioned condition for 3D TOF MRA of head are FOVc with 35 cm×35 cm, FOVs with 28 cm×28 cm, FOVp with 0.75 and R value with 1.25.

The therapeutic efficacy of hyperbaric oxygen in the treatment of non-arteritic anterior ischemic optic neuropathy / 中华物理医学与康复杂志

Objective@#To observe and explore the therapeutic efficacy of hyperbaric oxygen (HBO) in the treatment of non-arteritic anterior ischemic optic neuropathy (NAION).@*Methods@#A total of 139 NAION patients were randomly divided into a control group of 72 and a hyperbaric oxygen group of 67. Both groups were given conventional drugs including prednisolone, mecobalamin and compound anisodine, while the hyperbaric oxygen group was additionally provided with hyperbaric oxygen treatment at a pressure of 0.2MPa once a day for 30 days. Each day′s treatment lasted for 110 minutes, including 20 minutes at increasing pressure, 20 minutes decreasing and 60 minutes with the pressure stable at 0.2MPa. Before and after the 30-day treatment, the visual acuity and visual mean sensitivity (MS) of the two groups were observed and compared.@*Results@#There was no significant difference between the control group and the hyperbaric oxygen group in terms of average visual acuity or visual MS before the treatment. Afterward the average visual acuity (4.88±0.25) and visual MS (16.68±1.19) of the hyperbaric oxygen group were significantly higher than before the treatment and significantly better than those of the control group. The total effective rate of the hyperbaric oxygen group was 91%, significantly higher than that of the control group (75%).@*Conclusions@#Conventional treatment combined with hyperbaric oxygen therapy can significantly promote the visual acuity and visual MS of NAION patients.

Functional Evaluation of Transplanted Kidneys with Reduced Field-of-View Diffusion-Weighted Imaging at 3T

OBJECTIVE: To determine the feasibility of reduced field-of-view diffusion-weighted imaging (rFOV DWI) with multi-b values to detect functional variability in transplanted kidneys. MATERIALS AND METHODS: Using a 3T MRI scanner, multi-b rFOV DWI of transplanted kidney or native kidney was performed in 40 renal transplantation recipients and 18 healthy volunteers. The patients were stratified, according to an estimated glomerular filtration rate (eGFR): Group 1, eGFR ≥ 60 mL/min/1.73 m2; Group 2, eGFR ≥ 30 mL/min/1.73 m2 and < 60 mL/min/1.73 m2; Group 3, eGFR < 30 mL/min/1.73 m2. Total apparent diffusion coefficient (ADCT), perfusion-free ADC (ADCD) and perfusion fraction (FP) of kidneys were calculated and compared among the four groups. Correlations between the imaging results and eGFR were assessed. RESULTS: All volunteers had eGFR ≥ 60 mL/min/1.73 m2, while 16, 16, and 8 patients were included in Groups 1, 2, and 3, respectively. In the renal cortex, ADCT was higher in Group 1 ([1.65 ± 0.13] × 10−3 mm2/s) than Group 3 ([1.44 ± 0.11] × 10−3 mm2/s) (p < 0.05), and the inter-group differences of FP values were significant (all p < 0.05) (0.330 ± 0.024, 0.309 ± 0.019, 0.278 ± 0.033, and 0.250 ± 0.028 for control group, Groups 1, 2, and 3, respectively). Renal cortical ADCT, ADCD, FP, and renal medullary ADCT and FP correlated positively with eGFR (r = 0.596, 0.403, 0.711, 0.341, and 0.323, respectively; all p < 0.05). When using 0.278 as the cutoff value, renal cortical FP had a sensitivity of 97.1% and a specificity of 66.7% for predicting decreased renal function. CONCLUSION: Multi-b rFOV DWI presents transplanted kidneys with high resolution, which is a promising functional tool for non-invasively monitoring function of transplanted kidneys.

Diagnostic value of small field of view thin slice target scanning of pancreatic artery computed tomography enhanced angiography for pancreatic cancer / 第二军医大学学报

Objective To analyze the diagnostic value of computed tomography (CT) enhanced angiography of pancreatic artery with thin slice target scanning of field of view (FOV) for pancreatic cancer. Methods Clinical data of 36 patients with pancreatic cancer confirmed by postoperative pathology were collected. All patients received CT enhanced angiography of pancreatic artery with thin slice target scanning of FOV before operation, and the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the CT enhanced angiography of pancreatic artery with thin slice target scanning of FOV in evaluating tumor size, vascular invasion, arterial origin variation, and node metastasis were calculated with pathological results being the “gold standard”. The Kappa test was used to evaluate the diagnostic value of CT enhanced angiography of pancreatic artery with thin slice target scanning of FOV for pancreatic cancer. Results The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CT enhanced angiography of pancreatic artery with thin slice target scanning of FOV for tumor size were all 1.00; the diagnostic accuracy and sensitivity for vascular invasion and arterial origin variation were all 1.00, and the specificity was 0.97 or more; the diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for lymph node metastasis were 0.89, 0.75, 1.00, 1.00, and 0.83, respectively. The consistency of pathology and CT enhanced angiography of pancreatic artery with thin slice target scanning of FOV was good in evaluating pancreatic cancer (all Kappa0.75). Conclusion CT enhanced angiography of pancreatic artery with thin slice target scanning of FOV is a comprehensive method in evaluating pancreatic tumors, tumor margin, relationship between tumor and peripheral vessels, and peripheral lymph node metastasis, and it can improve the accuracy of surgical resectability evaluation of pancreatic cancer.

Reduced field-of-view diffusion weighted imaging in diagnosis of prostate cancer / 医学研究生学报

Objective With the improvement of technology and strategy , reduced field-of-view diffusion weighted imaging ( rFOV DWI) has provided more robust imaging .This article was intended to compare the clinical utility between rFOV DWI and con-ventional DWI in the diagnosis of prostate cancer . Methods Retrospective analysis was made on 58 prostate cancer patients under-going verification of biopsy or surgery after 3.0 T MRI rFOV DWI and regular DWI examinations in Nanjing General Hospital of Nan-jing Military Command from August 2014 to September 2015 , among whom prostate cancer and benign prostatic hyperplasia were 31 cases and 27 cases respectively .Independent grading was made by 2 radiol-ogists who were unaware of any clinical data and sequences in the as-pects of distortion on DW images , lesion conspicuity on DWI ( b=1000 ) and ADC images according to a 4-point Likert scale .rFOV and conventional DWI sequences were acquired using b =400,1000,0s/mm2.The IVIM double exponential model software was applied to generate ACD value, slow dispersive coefficient(D value) and parameterized image of volume fraction of fast dispersion (f value).Se-quence analysis was made in suspected peripheral tumor regions of prostate cancer patients and and healthy peripheral zones of patients with benign prostatic hyperplasia respectively to get ACD , D and f values .The ratio values rADC , rD and rf were attained compared with obturator internus .ROC analysis was made on the efficacy of different parameters of two sequences in prostate cancer . Results Image qualities of rFOV DWI were rated superior to conventional DWI (P<0.001,Wilcoxon Signed-Rank Test).Compared with con-ventional DWI, ADC value (0.728 ±0.094 vs 0.789 ±0.116, P<0.05)and D value(0.622 ±0.077 vs 0.651 ±0.099, P<0.05)of peripheral tumor regions in rFOV DWI were lower and the difference was statistically significant , whereas no significant difference was found in f value(P=0.932).No difference was found in area under ROC curve of f value between rFOV DWI and traditional DWI (0.853 vs 0.767, P=0.283). Conclusion The rFOV DWI sequence yielded can efficiently improve image quality , which is of important value to the clinical diagnosis of prostate cancer .

Reduced Field-of-View Diffusion-Weighted Magnetic Resonance Imaging of the Pancreas: Comparison with Conventional Single-Shot Echo-Planar Imaging

OBJECTIVE: To investigate the image quality (IQ) and apparent diffusion coefficient (ADC) of reduced field-of-view (FOV) di-ffusion-weighted imaging (DWI) of pancreas in comparison with full FOV DWI. MATERIALS AND METHODS: In this retrospective study, 2 readers independently performed qualitative analysis of full FOV DWI (FOV, 38 × 38 cm; b-value, 0 and 500 s/mm²) and reduced FOV DWI (FOV, 28 × 8.5 cm; b-value, 0 and 400 s/mm²). Both procedures were conducted with a two-dimensional spatially selective radiofrequency excitation pulse, in 102 patients with benign or malignant pancreatic diseases (mean size, 27.5 ± 14.4 mm). The study parameters included 1) anatomic structure visualization, 2) lesion conspicuity, 3) artifacts, 4) IQ score, and 5) subjective clinical utility for confirming or excluding initially considered differential diagnosis on conventional imaging. Another reader performed quantitative ADC measurements of focal pancreatic lesions and parenchyma. Wilcoxon signed-rank test was used to compare qualitative scores and ADCs between DWI sequences. Mann Whitney U-test was used to compare ADCs between the lesions and parenchyma. RESULTS: On qualitative analysis, reduced FOV DWI showed better anatomic structure visualization (2.76 ± 0.79 at b = 0 s/mm² and 2.81 ± 0.64 at b = 400 s/mm²), lesion conspicuity (3.11 ± 0.99 at b = 0 s/mm² and 3.15 ± 0.79 at b = 400 s/mm²), IQ score (8.51 ± 2.05 at b = 0 s/mm² and 8.79 ± 1.60 at b = 400 s/mm²), and higher clinical utility (3.41 ± 0.64), as compared to full FOV DWI (anatomic structure, 2.18 ± 0.59 at b = 0 s/mm² and 2.56 ± 0.47 at b = 500 s/mm²; lesion conspicuity, 2.55 ± 1.07 at b = 0 s/mm² and 2.89 ± 0.86 at b = 500 s/mm²; IQ score, 7.13 ± 1.83 at b = 0 s/mm² and 8.17 ± 1.31 at b = 500 s/mm²; clinical utility, 3.14 ± 0.70) (p 0.05). ADCs of adenocarcinomas (1.061 × 10⁻³ mm²/s ± 0.133 at reduced FOV and 1.079 × 10⁻³ mm²/s ± 0.135 at full FOV) and neuroendocrine tumors (0.983 × 10⁻³ mm²/s ± 0.152 at reduced FOV and 1.004 × 10⁻³ mm²/s ± 0.153 at full FOV) were significantly lower than those of parenchyma (1.191 × 10⁻³ mm²/s ± 0.125 at reduced FOV and 1.218 × 10⁻³ mm²/s ± 0.103 at full FOV) (p < 0.05). CONCLUSION: Reduced FOV DWI of the pancreas provides better overall IQ including better anatomic detail, lesion conspicuity and subjective clinical utility.

Volumetric and dosimetric variations in radiation treatment planning using CT images based on different reconstructed field-of-view / 中华放射医学与防护杂志

Objective To analyze the volumetric and dosimetric variations in radiation treatment planning(RTP) using CT images based on normal and extended reconstructed field-of-view(FOV). Methods Original data of CT scans from 16 cases of nasopharyngeal carcinomas were reconstructed to form 2 sets of CT images with Dermal(45 cm)and EFOV(65 cm),which were then exposed to RTP. Contouring of targets/OAR including GTV(gross tumor volume),CTV(clinical target volume,CTV),brain stem, lens, parotids and cord was made on normsl FOV CT set.A 7-field equi-angular IMRT (intensity modulated radiation Therapy)plan was generated with prescribed GTV dose of 70 Gy.Two sets 0f CT images were fused in DICOM coordinate system and targets/OARs on normal FOV CT were copied to EFOV CT.IMRT plans were then transplanted from normal FOV to EFOV CT,with the same isocenter on DICOM coordinates.Volumetric and dosimetrie variations including GTV,CTV brain stem,lens, parotids and cord were calculated on dose-volume-histogram(DVH).For dosimetric verification,IMRT plans were input into fluence maps of Mapcheck 1175 phantom based on normal FOV and EFOV, and DTA(distance to agreement)was used to analyze the passing rate of calculated/measured absolute doses at 5 cm depth.Paired-t test was used to compare the passing rate of field 1-7 of IMRT plans based on 2 CT sets.Results Volumes of targets and OARs on 2 CT sets of different FOVs were statistically different.with larger calculated volume on norlual FOV in all cases.There was no statistic difference in the maximal(Dmax) doses received by all targets and OARs except the small-volume lens, in which the dose was higher on normal CT than that on EFOV CT(t=-3.14,P<0.007).The mean doses(Dmean)to the CTV(clinical target volume)and GTV(gross tumor volume)were higher on EFOV than normal FOV CT(t=-6.45,-5.65,P<0.001).There was no statistic difference in Dmean received by OARs and the minimal dose (Dmin)by all targets and OARs(P>0.05).There was also no statistic difference in the passing rate of field 1-7 of IMRT plans based on 2 CT sets.Conclusions There were volumetric and dosimetric variations as evaluated on DVH using different reconstructed FOV during CT simulation,though the difference between the passing rates as verified in 2 dimensional fluence map was not significant.

Clinical Application of Medical Ultrasonic Technique / 医疗卫生装备

The clinic main application of medical ultrasonic techniques are introduced,including ophthalmology,neurology,angiology,cardiopathy,digestive system,urology,gynaecology and obstetrics,and surgery. Four kinds of medical ultrasonic techniques in the value on the clinic diagnosis are important,namely transcranial color -coded duplex sonography(TCCD),tissue harmonic imaging(THI),three dimensional imaging(3D),and extended field Of view(EFV).