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Objective:To investigate impacts of a deep learning image reconstruction (DLIR) algorithm on image quality of lower extremity CTA with low kVp and reverse flow direction scanning.Methods:From January 2021 to March 2021, fifty patients with suspected lower extremities diseases and received lower extremity CTA with low kVp and reverse flow direction scanning in Union Hospital affiliated to Fujian Medical University were retrospectively collected in this study. Six groups of CT images were reconstructed at the thickness of 0.625 mm using two algorithms including ASIR-V of three blending ratios (ASIR-V 20%, ASIR-V 50% and ASIR-V 80%) and DLIR of three strengths (DLIR-H, DLIR-M and DLIR-L). Regions of interest (ROIs) were placed on proximal abdominal aorta (AA), distal AA, left and right common iliac arteries, left and right femoral arteries (upper segment), left and right superficial femoral arteries (middle segment), left and right popliteal arteries. The CT value and SD value were measured for each group; the signal-noise ratio (SNR) and contrast-noise ratio (CNR) were calculated. The lower extremity CTA was divided into four segments, and the subjective evaluation was independently performed on noise and sharpness using 4 points scales by two radiologists. One-way analysis of variance was utilized to evaluate the differences in subjective scoring and objective parameters among the six groups.Results:For all arteries segments, with the increase of blending ratios for ASIR-V and reconstruction strength of DLIR, the SD values were reduced while SNR and CNR were increased (all P<0.05). Among the six groups, DLIR-H and ASIR-V80% images had lowest SD as well as highest SNR and CNR (all P<0.05). In comparison to ASIR-V20% and ASIR-V50% images, DLIR-H images showed lower SD, higher SNR and CNR values (all P<0.05). There were no statistical differences between ASIR-V80% and DLIR-H images in SD, SNR and CNR values (all P>0.05). Subjective scoring results showed that the DLIR-H images displayed the best noise performance for the entire lower extremity arteries from AA to the foot artery, and the sharpness scores of DLIR-H images were also significantly higher than ASIR-V80% (all P<0.05). Conclusion:DLIR can significantly reduce the image noise and improve the image quality in CTA for abdominal aorta to lower extremity arteries. DLIR-H showed the greatest noise reduction ability and the best effect balancing noise and sharpness, providing highest image quality.
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Objective@#To evaluate the application of laplacian-regularized mean apparent propagator (MAPL)-MRI to brain glioma-induced corticospinal tract (CST) injury. @*Materials and Methods@#This study included 20 patients with glioma adjacent to the CST pathway who had undergone structural and diffusion MRI. The entire CSTs of the affected and healthy sides were reconstructed, and the peritumoral CSTs were manually segmented. The morphological characteristics of the CST (track number, average length, volume, displacement of the affected CST) were examined and the diffusion parameter values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), mean squared displacement (MSD), q-space inverse variance (QIV), returnto-origin probability (RTOP), return-to-axis probabilities (RTAP), and return-to-plane probabilities (RTPP) along the entire and peritumoral CSTs, were calculated. The entire and peritumoral CST characteristics of the affected and healthy sides as well as those relative CST characteristics of the patients with motor weakness and normal motor function were compared. @*Results@#The track number, volume, MD, RD, MSD, QIV, RTAP, RTOP, and RTPP of the entire and peritumoral CSTs changed significantly for the affected side, whereas the AD and FA changed significantly only in the peritumoral CST (p 0.05 for all). @*Conclusion@#MAPL-MRI is an effective approach for evaluating microstructural changes after CST injury. Its sensitivity may improve when using the peritumoral CST features.
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Objective@#To evaluate the application of laplacian-regularized mean apparent propagator (MAPL)-MRI to brain glioma-induced corticospinal tract (CST) injury. @*Materials and Methods@#This study included 20 patients with glioma adjacent to the CST pathway who had undergone structural and diffusion MRI. The entire CSTs of the affected and healthy sides were reconstructed, and the peritumoral CSTs were manually segmented. The morphological characteristics of the CST (track number, average length, volume, displacement of the affected CST) were examined and the diffusion parameter values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), mean squared displacement (MSD), q-space inverse variance (QIV), returnto-origin probability (RTOP), return-to-axis probabilities (RTAP), and return-to-plane probabilities (RTPP) along the entire and peritumoral CSTs, were calculated. The entire and peritumoral CST characteristics of the affected and healthy sides as well as those relative CST characteristics of the patients with motor weakness and normal motor function were compared. @*Results@#The track number, volume, MD, RD, MSD, QIV, RTAP, RTOP, and RTPP of the entire and peritumoral CSTs changed significantly for the affected side, whereas the AD and FA changed significantly only in the peritumoral CST (p 0.05 for all). @*Conclusion@#MAPL-MRI is an effective approach for evaluating microstructural changes after CST injury. Its sensitivity may improve when using the peritumoral CST features.
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Objective:To explore the technical advantages of MR cholangiopancreatography (MRCP) with single breath holding high parallel acquisition factor 3-D variable flip angle fast spin echo (3D-SPACE) sequence.Methods:From November 2018 to March 2019, 75 patients who underwent MRCP examination in our hospital were prospectively enrolled, with single breath holding high parallel acquisition factor 3D-SPACE sequence and free breathing navigation gated 3D-SPACE sequence. Three experienced radiologists scored the overall image quality, artifacts, CBD visibility, left and right hepatic ducts, right anterior and posterior branches, second and third branches, main pancreatic duct and gallbladder duct with four scales. Paired t test was used for statistical analysis. Results:The scanning time of single breath holding method (18 s) was significantly shorter than that of free breathing diaphragm navigation method［264（226，313）s］, and the difference between the two methods was statistically significant ( Z=-7.520， P<0.001). The SNR, CR and CNR (8.31±4.23, 0.92±0.30, 11.46±5.77) of single breath holding method were lower than those of free breathing diaphragm navigation method (11.23±5.70, 0.93±0.38, 15.06±7.37), and the differences between the two methods were also statistically significant ( t=4.378, 3.429, 4.063, P<0.05). The overall image quality, artifact, the CBD, left and right hepatic duct, right anterior and posterior branchs, the second and third branches, main pancreatic duct and cystic duct of single breath holding method were higher than those of free breathing diaphragm navigation method, and the differences between the two methods were statistically significant ( P<0.001). Conclusions:Compared with the free breathing diaphragm navigation gated 3D-SPACE MRCP imaging method, the single breath holding high parallel acquisition factor 3D-SPACE MRCP imaging method has less artifacts and examination time, but higher visibility to pancreaticobiliary tree and work efficiency, which is worthy of further promotion.
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Objective@#To investigate the differences of gemstone spectral curve and CT value of gastric cancer with different pathological types and differentiation degrees.@*Methods@#91 cases of preoperative gemstone CT images with gastric cancer were collected, including 24 cases of mucinous carcinoma, 67 cases of non-mucinous carcinoma, 16 cases of signet ring cell carcinoma, 8 cases of mucinous adenocarcinoma, 32 cases of moderately differentiated adenocarcinoma and 35 cases of poorly differentiated adenocarcinoma. Gemstone CT spectral imaging was performed preoperatively, and the spectral curve of the lesion in venous phase was obtained by using GSI Viewer software, the slope of the curve was calculated, and 11 monoenergetic CT values of 40~140 keV (10 keV interval) were measured. The gemstone spectral curves and CT values of gastric cancer with different pathological types and differentiation degrees are compared.@*Results@#The curve slopes of non-mucinous carcinoma, signet ring cell carcinoma and poorly differentiated adenocarcinoma were -1.92±0.53, -1.73±0.37 and -2.14±0.54, respectively. The absolute values were higher than those of mucinous carcinoma (-1.45±0.54), mucinous adenocarcinoma (-0.90±0.34) and moderately differentiated adenocarcinoma (-1.67±0.41), and the differences were all statistically significant (P<0.05). There were significant differences in monoenergetic CT values between mucinous and non-mucinous carcinomas at 40-140 keV (all P<0.05). The former was lower than the latter in different degrees, and the lower the energy, the greater the difference was. There were significant differences in monoenergetic CT values between signet ring cell carcinoma and mucinous adenocarcinoma at 40-100 keV (all P<0.05); monoenergetic CT values between poorly differentiated adenocarcinoma and moderately differentiated adenocarcinoma at 40-90 keV showed statistically significant differences (P<0.05).@*Conclusions@#Gastric cancer with different pathological types and differentiation degrees have their characteristic spectral curves in venous phase, and the monoenergetic CT values are significantly different at low energy. The spectral curve of gemstone CT may be helpful to evaluate the pathological type and differentiation degree of gastric cancer before operation.
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Objective To investigate the value of wide-detector Revolution CTA with 70 kV tube voltage and prospective ECG-gated technique in diagnosis of congenital heart disease (CHD) in infants and children.Methods Forty-five infants and children with complicated CHD underwent echocardiography and wide-detector Revolution CTA.According to the sur gical findings,the diagnostic efficiency of Revolution CTA and echocardiography were calculated and compared.The radiation effective dose (ED) and iodine dose were calculated.The quality of CT images was also evaluated.Results There were 25 separate cardiovascular anomalies including 6 congenital cardiac structure anomalies and 19 congenital extracardiac vascular anomalies.For congenital extracardiac vascular anomalies,there was significant difference of diagnostic accuracy and the detectable rate between CTA (99.77％ [853/855],97.73％ [86/88]) and echocardiography (98.71％ [844/855],88.64％ [78/88];x2 =6.28,5.72,both P＜0.05).The average of ED was (0.20±0.05)mSv and the mean iodine dose was (2.06± 1.09)g.All CT images were qualified for diagnosis.Conclusion The wide-detector Revolution CTA,with the prospective ECG-gated technique and 70 kV tube voltage,can provide high accuracy for assessment of CHD in infants and children,which can keep good image quality,with the low radiation dose.
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Objective To investigate the clinical value of gemstone spectral imaging (GSI) associated with patient-based low dose of contrast medium protocol in carotid CTA. Methods One hundred and twenty patients who were suspected with stenotic carotid artery or carotid plaque were prospectively enrolled in the study. All of them were divide into two groups by random number table. Group A (routine group): 60 were scanned with 120 kVp after the administration of moderate-concentration CM(320 mg/ml) with 5 ml/s injection velocity, Group B (low dose group):60 were scanned with GSI which was reconstructed using 50%ASiR after the administration of the same CM with 3 ml/s injection velocity. The contrast dose [(test bolus peak time +2 s – 5 s) × injection velocity] was calculated. Images of the two groups were compared in terms of arterial attenuation, signal-noise-ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality (IQ) score. The value of CT dose index volume (CTDIvol), dose length product (DLP) and effective dose (ED) was recorded, respectively. Data were analyzed by using independent samples t test or Mann-Whitney U test. Results The mean attenuation, noise, SNR, CNR, subjective image quality score, contrast dose, CTDIvol, DLP and ED of routine group was (363 ± 56)HU, (13 ± 4)HU, 30 ± 10, 38±13, 3.0 score, (69 ± 13) ml, 13.61 mGy,527 mGy · cm and 3.11 mSv, respectively. The above variables of low-dose-group was (378 ± 69) HU, (9 ± 4)HU, 48 ± 19, 62 ± 24, 2.0 score,(49 ± 7)ml, 12.72 mGy, 478 mGy · cm and 2.82 mSv, respectively. The mean attenuation and subjective IQ score of carotid artery had no significant differences statistically between two groups (P>0.05), respectively. The noise, SNR, CNR, contrast dose, CTDIvol, DLP and ED had significant differences statistically between two groups (P<0.05), respectively. Conclusion Compared with 120 kVp protocol, the use of GSI associated with patient-based low dose of contrast medium protocol in carotid CTA could provide equivalent image quality and higher SNR and CNR of carotid artery with a smaller amount of iodine and a lower radiation dose.
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Objective To evaluate spectral CT imaging in characterizing the pathological type and the differentiation of gastric cancer.Methods Ninety-one patients diagnosed of gastric cancer were retrospectively analyzed.Patients were all underwent triple-phase enhanced scan using single source dualenergy CT on gemstone spectral imaging(GSI) mode.Three types of images were reconstructed for analysis:the water concentration (WC),iodine concentration (IC),and normalized iodine concentration (NIC).The patients were divided into groups of mucinous carcinoma (MUC),including mucinous adenocarcinoma and signet ring cell carcinoma,and non-mucinous gastric carcinoma (non-MUC).Independent-samples t test was used for statistical analysis.Results There were 24 patients of MUC and 67 patients of non-MUC.The IC and NIC of the non-MUC were significantly higher than the MUC in vein phase (VP) and in parenchymal phase (PP) [(21.33 ±6.31) × 100 vs (16.94 ±6.13) × 100 μg/ml,0.55 ±0.17 vs 0.42 ±0.14 in VP,and(20.65 ±5.49) × 100 vs (18.07 ±4.51) × 100 μg/ml,0.72 ±0.20 vs 0.57 ±0.12 in PP,respectively t =-2.948,-3.362,-2.261,-4.326,P ＜0.05].The IC and NIC of the signet ring cell carcinoma were statistically higher than those of the mucinous adenocarcinoma [(19.36 ± 4.75) × 100 vs (12.10 ±5.92) ×100μg/ml,0.49 ± 0.09 vs0.28±0.11 in VP,and (19.88±3.28) ×100 vs (14.45±4.62) ×100 μg/ml,0.63 ±0.08 vs 0.47 ±0.11 in PP,respectively t =3.253,5.180,3.339,3.850,P ＜0.01].For the poorly differentiated and well /moderately differentiated adenocarcinoma,the IC and NIC of the former were higher than those of the latter in VP and PP [(23.48 ±6.49) × 100 vs (18.98 ±5.26) × 100 μg/ml,0.61±0.16vs0.48±0.15 in VP,and (22.95±5.51) ×100 vs (18.28±4.47) ×100 μg/ml,0.81 ± 0.21 vs 0.63 ± 0.15 in PP,respectively t =3.098,3.249,3.766,4.117,P ＜ 0.01].The between-group differences of WC,IC and NIC in artery phase were no significant (P ＞ 0.05).Conclusions Different pathological types could determine different IC.The spectral CT imaging may be helpful for characterizing the pathological type of gastric cancer.
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Objective To evaluate the value of MRI in qualitative and quantitative diagnosis of bone marrow involvement in patients with lymphoma. Methods 28 diagnosed lymphoma with bone marrow infiltration and 31 healthy spines as controls were included.MRI performance and the signal intensity ratio on T1WI (SIR1) of the spine bone marrow and cerebrospinal fluid were analyzed and statistical analyses were performed.Results Qualitative diagnosis among these patients,was shown than MRI results indicated that 27 cases had abnormal signal. The sensitivity of MRI was 96.4 ％. There were four main patterns of marrow infiltration in MRI,containing nodular pattern 21.4 ％ (6/28),scattered pattern 53.6 ％ (15/28),mottled pattern 14.3 ％ (4/28) and uniform pattern 7.1％ (2/28) respectively.By quantitative diagnosis the SIR1 of study group (1.251±0.253) was apparently lower than that in the control group (2.625±0.434) with statistical significance (t =15.022,P ＜ 0.001).The results of multiple comparisons showed that the SIR1 of mild degree (1.390±0.172),moderate degree (0.982±0.790) and severe degree (0.908±0.122) patients with lymphoma compared with the normal controls had significant differences (all P =0.000),and difference between mild and moderate degree had statistical significance (LSD,P =0.012),so did the difference between mild and severe degree (LSD,P =0.025).However,no significant difference could be seen between moderate and severe degree (LSD, P =0.757). Positive linear correlation was existed between the persentages of SIR1 and tumor cells in bone marrow (r =-0.765, P ＜ 0.001). Conclusion As a noninvasive and direct-viewing technique, MRI presents a global view of bone marrow with high sensitivity in detecting bone marrow involvement in lymphoma. To a certain extent, it could be possible to estimate the infiltration degree and evaluation of the tumor burden in bone marrow by quantitative measurement of MRI.
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Objective To investigate the limitation of quantitative measurement of cerebral blood flow (CBF) of normal white matter by using a single subtraction with thin-slice TI1 periodic saturation (Q2TIPS Ⅱ ) pulsed arterial spin labeling (PASL)technique. Methods Thirty-one patients with brain tumors were examined at 3.0 T MRI system . A second version of quantitative imaging of perfusion using a single subtraction with additional thin-section periodic saturation after inversion and a time delay (Q2TIPS) technique of pulsed arterial spin labeling in the multisection mode and T2* dynamic susceptibility-weighted contrast-enhanced (T2* DSC)MR imaging were both implemented. Cerebral blood flow map obtained from PASL and DSC were reviewed. The regions of interest( ROI )were placed in the region of normal white matter contralateral to the lesion in the proximal and distal slices. In regions of interest, the signal intensity (SI)was measured from the maps of cerebral blood flow map obtained from PASL and DSC. Pair-t test was performed to determine if there were significant signal differences between proximal and distal slices. Pearson linear correlation analysis of signal intensity was performed for values from the same slices of PASL-CBF and DSC-CBF maps. Results In the deep white matter of distal slice, PASL-CBF map showed perfusion deficit while DSC-CBF map showed low CBF in the corresponding brain area. With the increased inversion time,the PASL-CBF map showed obviously improved perfusion signal in deep white matter (but still some perfusion deficit)and slightly decreased perfusion signal in grey matter. The mean signal of normal white matter measured from distal slices of PASL-CBF maps was( -22.1 ±55.5) ml· 100 g-1 · min-1 while it was (89.5 ±45.5) ml. 100 g-1 · min-1 in proximal slices. There was a significant difference of signal intensity from PASL-CBF maps between distal and proximal slices ( t = - 9. 512, P ＜ 0. 01 ＝, while no difference of signal intensity between distal[ (62. 8 ± 29.9) ml · 100 g-1 · min-1] and proximal slices [(57. 1 ±29.6) ml · 100 g-1 · min-1 ]was obtained from DSC-CBF maps(t= -1.607,P＞0.05). There was no significant correlation between PASL-CBF and DSC-CBF in both distal ( r = 0. 093, P ＞ 0. 05 ) and proximal slices ( r = - 0. 234, P ＞ 0. 05). ConclusionsPASL has limitation in the accurate quantification of cerebral blood flow of normal white matter. The quantification of CBF was affected by the limitations of the technique itself and the different parameters chosen..
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Objective To investigate variation in the carotid bifurcation geometry of adults of different age by MR angiography images combining image post-processing technique. Methods Images of the carotid bifurcations of 27 young adults (≤40 years old) and 30 older subjects ( >40 years old) were acquired via contrast-enhanced MR angiography. Three dimensional (3D) geometries of the bifurcations were reconstructed and geometric parameters were measured by post-processing technique. Results The geometric parameters of the young versus older groups were as follows: bifurcation angle (70.268°± 16.050° versus 58.857°±13.294°), ICA angle (36.893°±11.837° versus 30.275°± 9.533°), ICA planarity (6.453°±5.009° versus 6.263°±4.250°),CCA tortuosity (0.023°0.011 versus 0.014± 0.005), ICA tortuosity (0.070±0.042 versus 0.046±0.022), ICA/CCA diameter ratio (0.693± 0.132 versus 0.728±0.106), ECA/CCA diameter ratio (0.750±0.123 versus 0.809±0.122), ECA/ ICA diameter ratio (1.103±0.201 versus 1.127±0.195), bifurcation area ratio (1.057±0.281 versus 1.291±0.252). There was significant statistical difference between young group and older group in bifurcation angle, ICA angle, CCA tortuosity, ICA tortuosity, ECA/CCA and bifurcation area ratio (F= 17.16,11.74,23.02,13.38,6.54,22.80,respectively, P<0.05). Conclusions MR angiography images combined with image post-processing technique can reconstruct 3D carotid bifurcation geometry and measure the geometric parameters of carotid bifurcation in vivo individually. It provides a new and convenient method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes.
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Objective To investigate the visualization and quantitation of hemodynamic variables at carotid artery bifurcation in vivo by combining computational fluid dynamics(CFD)and vascular imaging. Methods A healthy volunteer underwent CT angiography of left carotid artery by SIEMENS multi-slice CT. Parameters of hemodynamics at this carotid bifurcation were calculated and visualized by combining vascular imaging post-processing and CFD.Results (1) The average range of flow velocity was 0.04～0.36 m/s. A region of high velocity was seen at medial wall of internal carotid artery (ICA) and medial wall of external carotid artery (ECA), respectively. The largest contiguous region of low velocity occurred at the carotid bulb. (2)The average range of absolute pressure, static pressure and dynamic pressure was 100 266.70～101 615.90 Pa, -1058.34～290.88 Pa, and 6.12～553.25 Pa, respectively. (3) The average range of wall shear stress (WSS) at the bifurcation was 0.59～5.35 Pa. There was a large region of low WSS at carotid bulb and posterior wall of ICA, with the lowest value of 0.25 Pa. Also there was a small region of low WSS at anterior and lateral wall of ECA.Conclusion CFD combined with vascular imaging can calculate and visualize the parameters of hemodynamics at carotid bifurcation in vivo individually. It is an interdisciplinary science of computer, radiology and hemodynamics and provides a new method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes.