Pre-operative enhanced magnetic resonance imaging combined with clinical features predict early recurrence of hepatocellular carcinoma after radical resection

BACKGROUND Indentifying predictive factors for postoperative recurrence of hepatocellular carcinoma(HCC)has great significance for patient prognosis.AIM To explore the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(Gd-EOB-DTPA)enhanced magnetic resonance imaging(MRI)combined with clinical features in predicting early recurrence of HCC after resection.METHODS A total of 161 patients with pathologically confirmed HCC were enrolled.The patients were divided into early recurrence and non-early recurrence group based on the follow-up results.The clinical,laboratory,pathological results and Gd-EOB-DTPA enhanced MRI imaging features were analyzed.RESULTS Of 161 patients,73 had early recurrence and 88 were had non-early recurrence.Univariate analysis showed that patient age,gender,serum alpha-fetoprotein level,the Barcelona Clinic Liver Cancer stage,China liver cancer(CNLC)stage,microvascular invasion(MVI),pathological satellite focus,tumor size,tumor number,tumor boundary,tumor capsule,intratumoral necrosis,portal vein tumor thrombus,large vessel invasion,nonperipheral washout,peritumoral enhancement,hepatobiliary phase(HBP)/tumor signal intensity(SI)/peritumoral SI,HBP peritumoral low signal and peritumoral delay enhancement were significantly associated with early recurrence of HCC after operation.Multivariate logistic regression analysis showed that patient age,MVI,CNLC stage,tumor boundary and large vessel invasion were independent predictive factors.External data validation indicated that the area under the curve of the combined predictors was 0.861,suggesting that multivariate logistic regression was a reasonable predictive model for early recurrence of HCC.CONCLUSION Gd-EOB-DTPA enhanced MRI combined with clinical features would help predicting the early recurrence of HCC after operation.

Optimization of hepatobiliary phase delay time of Gd-EOB-DTPA-enhanced magnetic resonance imaging for identification of hepatocellular carcinoma in patients with cirrhosis of different degrees of severity

AIM To optimize the hepatobiliary phase delay time(HBPDT) of Gd-EOB-DTPA-enhanced magnetic resonance imaging(GED-MRI) for more efficient identification of hepatocellular carcinoma(HCC) occurring in different degrees of cirrhosis assessed by Child-Pugh(CP) score.METHODS The liver parenchyma signal intensity(LPSI), the liver parenchyma(LP)/HCC signal ratios, and the visibility of HCC at HBP-DT of 5, 10, 15, 20, and 25 min(i.e., DT-5, DT-10, DT-15, DT-20, and DT-25) after injection of GdEOB-DTPA were collected and analyzed in 73 patients with cirrhosis of different degrees of severity(including 42 patients suffering from HCC) and 18 healthy adult controls.RESULTS The LPSI increased with HBP-DT more significantly in the healthy group than in the cirrhosis group(F = 17.361, P < 0.001). The LP/HCC signal ratios had a significant difference(F = 12.453, P < 0.001) among various HBP-DT points, as well as between CP-A and CP-B/C subgroups(F = 9.761, P < 0.001). The constituent ratios of HCC foci identified as obvious hypointensity(+++), moderate hypointensity(++), and mild hypointensity or isointensity(+/-) kept stable from DT-10 to DT-25: 90.6%, 9.4%, and 0.0% in the CP-A subgroup; 50.0%, 50.0%, and 0.0% in the CP-B subgroup; and 0.0%, 0.0%, and 100.0% in the CP-C subgroup, respectively.CONCLUSION The severity of liver cirrhosis has significant negative influence on the HCC visualization by GED-MRI. DT-10 is more efficient and practical than other HBP-DT points to identify most of HCC foci emerging in CP-A cirrhosis, as well as in CP-B cirrhosis; but an HBP-DT of 15 min or longer seems more appropriate than DT-10 for visualization of HCC in patients with CP-C cirrhosis.

Endorectal ultrasonography versus phased-array magnetic resonance imaging for preoperative staging of rectal cancer

AIM: To compare the diagnostic accuracy of pelvic phased-array magnetic resonance imaging (MRI) and endorectal ultrasonography (ERUS) in the preoperative staging of rectal carcinoma. METHODS: Thirty-four patients (15 males, 19 females) with ages ranging between 29 and 75 who have biopsy proven rectal tumor underwent both MRI and ERUS examinations before surgery. All patients were evaluated to determine the diagnostic accuracy of depth of transmural tumor invasion and lymph node metastases. Imaging results were correlated with histopathological findings regarded as the gold standard and both modalities were compared in terms of predicting preoperative local staging of rectal carcinoma. RESULTS: The pathological T stage of the tumors was: pT1 in 1 patient, pT2 in 9 patients, pT3 in 21 patients and pT4 in 3 patients. The pathological N stage of the tumors was: pN0 in 19 patients, pN1 in 9 patients and pN2 in 6 patients. The accuracy of T staging for MRI was 89.70% (27 out of 34). The sensitivity was 79.41% and the specificity was 93.14%. The accuracy of T staging for ERUS was 85.29% (24 out of 34). The sensitivity was 70.59% and the specificity was 90.20%. Detection of lymph node metastases usingphased-array MRI gave an accuracy of 74.50% (21 out of 34). The sensitivity and specificity was found to be 61.76% and 80.88%, respectively. By using ERUS in the detection of lymph node metastases, an accuracy of 76.47% (18 out of 34) was obtained. The sensitivity and specificity were found to be 52.94% and 84.31%, respectively. CONCLUSION: ERUS and phased-array MRI are complementary methods in the accurate preoperative staging of rectal cancer. In conclusion, we can state that phased-array MRI was observed to be slightly superior in determining the depth of transmural invasion (T stage) and has same value in detecting lymph node metastases (N stage) as compared to ERUS.

Diagnostic value of gadobenate dimeglumine-enhanced hepatocyte-phase magnetic resonance imaging in evaluating hepatic fibrosis and hepatitis

AIM To evaluate the diagnostic value of gadobenate dimeglumine(Gd-BOPTA)-enhanced hepatocyte-phase magnetic resonance imaging(MRI) in evaluating hepatic fibrosis and hepatitis.METHODS Hepatocyte-phase images of Gd-BOPTA-enhanced MRI were retrospectively evaluated in 76 patients with chronic liver disease. These patients were classified into five groups according to either the histopathological fibrosis stage(S0-S4) or the histopathological hepatitis grade(G0-G4). The relative enhancement ratio(RE) of the liver parenchyma in the T1-vibe sequence was calculated by measuring the signal intensity before(SI pre) and 90 min after(SI post) intravenous injection of Gd-BOPTA using the following formula: RE =(SI post-SI pre)/SI pre. One-way analysis of variance was used to compare the difference between the relative RE in the hepatocyte phase(REh) and the stage of hepatic fibrosis and the grade of hepatitis. Pearson's productmoment correlation analysis was used to evaluate the relationship between the REh and the levels of serologic liver functional parameters.RESULTS According to histopathological hepatic fibrosis stage, the 76 patients were classified into five groups: 16 in S0, 15 in S1, 21 in S2, 9 in S3, and 15 in S4 group. According to histopathological hepatitis grade, the 76 patients were also classified into five groups: 0 in G0, 44 in G1, 22 in G2, 8 in G3, and 2 in G3 group. With regard to the stage of hepatic fibrosis, REh showed significant differences between the S2 and S3 groups and between the S2 and S4 groups(P < 0.05), but no significant difference was observed between the other groups. With regard to the grade of hepatitis, REh showed significant differences between the G1 and G2 groups and between the G1 and G4 groups(P < 0.05), but no significant difference was observed between the other groups. Increased REh showed correlations with decreased serum levels of TB, ALT and AST(P < 0.05). CONCLUSION To some extent, measuring the REh using Gd-BOPTAenhanced MRI might be a noninvasive technique for assessing the stage of hepatic fibrosis. This method is able to differentiate no/mild hepatitis from advanced hepatitis. TB, ALT and AST levels can predict the degree of liver enhancement in the hepatocyte phase of Gd-BOPTA-enhanced MRI.

Designing shielded radio-frequency phased-array coils for magnetic resonance imaging

In this paper, an approach to the design of shielded radio-frequency （RF） phased-array coils for magnetic resonance imaging （MRI） is proposed. The target field method is used to find current densities distributed on primary and shield coils. The stream function technique is used to discretize current densities and to obtain the winding patterns of the coils. The corresponding highly ill-conditioned integral equation is solved by the Tikhonov regularization with a penalty function related to the minimum curvature. To balance the simplicity and smoothness with the homogeneity of the magnetic field of the coll＇s winding pattern, the selection of a penalty factor is discussed in detail.

Four-dimensional flow magnetic resonance imaging incirrhosis

Since its introduction in the 1970’s,magnetic resonance imaging(MRI)has become a standard imaging modality.With its broad and standardized application,it is firmly established in the clinical routine and an essential element in cardiovascular and abdominal imaging.In addition to sonography and computer tomography,MRI is a valuable tool for diagnosing cardiovascular and abdominal diseases,for determining disease severity,and for assessing therapeutic success.MRI techniques have improved over the last few decades,revealing not just morphologic information,but functional information about perfusion,diffusion and hemodynamics as well.Four-dimensional(4D)flow MRI,a time-resolved phase contrast-MRI with three-dimensional(3D)anatomic coverage and velocity encoding along all three flow directions has been used to comprehensively assess complex cardiovascular hemodynamics in multiple regions of the body.The technique enables visualization of 3D blood flow patterns and retrospective quantification of blood flow parameters in a region of interest.Over the last few years,4D flow MRI has been increasingly performed in the abdominal region.By applying different acceleration techniques,taking 4D flow MRI measurements has dropped to a reasonable scanning time of 8 to 12 min.These new developments have encouraged a growing number of patient studies in the literature validating the technique’s potential for enhanced evaluation of blood flow parameters within the liver’s complex vascular system.The purpose of this review article is to broaden our understanding of 4D flow MRI for the assessment of liver hemodynamics by providing insights into acquisition,data analysis,visualization and quantification.Furthermore,in this article we highlight its development,focussing on the clinical application of the technique.

Application of MAGnetic resonance imaging compilation in acute ischemic stroke

BACKGROUND Synthetic magnetic resonance imaging(MRI)MAGnetic resonance imaging compilation(MAGiC)is a new MRI technology.Conventional T1,T2,T2-fluidattenuated inversion recovery(FLAIR)contrast images,quantitative images of T1 and T2 mapping,and MAGiC phase sensitive inversion recovery(PSIR)Vessel cerebrovascular images can be obtained simultaneously through post-processing at the same time after completing a scan.In recent years,studies have reported that MAGiC can be applied to patients with acute ischemic stroke.We hypothesized that the synthetic MRI vascular screening scheme can evaluate the degree of cerebral artery stenosis in patients with acute ischemic stroke.AIM To explore the application value of vascular images obtained by synthetic MRI in diagnosing acute ischemic stroke.METHODS A total of 64 patients with acute ischemic stroke were selected and examined by MRI in the current retrospective cohort study.The scanning sequences included traditional T1,T2,and T2-FLAIR,three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA),diffusion-weighted imaging(DWI),and synthetic MRI.Conventional contrast images(T1,T2,and T2-FLAIR)and intracranial vessel images(MAGiC PSIR Vessel]were automatically reconstructed using synthetic MRI raw data.The contrast-to-noise ratio(CNR)values of traditional T1,T2,and T2-FLAIR images and MAGiC reconstructed T1,T2,and T2-FLAIR images in DWI diffusion restriction areas were measured and compared.MAGiC PSIR Vessel and TOF MRA images were used to measure and calculate the stenosis degree of bilateral middle cerebral artery stenosis areas.The consistency of MAGiC PSIR Vessel and TOF MRA in displaying the degree of vascular stenosis with computed tomography angiography(CTA)was compared.RESULTS Among the 64 patients with acute ischemic stroke,79 vascular stenosis areas showed that the correlation between MAGiC PSIR Vessel and CTA(r=0.90,P<0.01)was higher than that between TOF MRA and CTA(r=0.84,P<0.01).With a degree of vascular stenosis>50%assessed by CTA as a reference,the area under the receiver operating characteristic(ROC)curve of MAGiC PSIR Vessel[area under the curve(AUC)=0.906,P<0.01]was higher than that of TOF MRA(AUC=0.790,P<0.01).Among the 64 patients with acute ischemic stroke,39 were scanned for traditional T1,T2,and T2-FLAIR images and MAGiC images simultaneously,and CNR values in DWI diffusion restriction areas were measured,which were:Traditional T2=21.2,traditional T1=-6.7,and traditional T2-FLAIR=11.9;and MAGiC T2=7.1,MAGiC T1=-3.9,and MAGiC T2-FLAIR=4.5.CONCLUSION The synthetic MRI vascular screening scheme for patients with acute ischemic stroke can accurately evaluate the degree of bilateral middle cerebral artery stenosis,which is of great significance to early thrombolytic interventional therapy and improving patients’quality of life.

Indeterminate liver lesions on gadoxetic acid-enhanced magnetic resonance imaging of the liver:Case-based radiologic-pathologic review

Different histopathological manifestations of focal liver lesions show varying common and uncommon imaging findings and some pathologies may show similar appearance despite of different histopathology.It is necessary to characterise focal liver lesions accurately as not only benign and malignant lesions are managed differently,but also certain benign lesions have differing management.These lesions are increasingly being detected due to rapid growth of use of crosssectional imaging as well as improvement in image quality and new imaging techniques.Contrast enhanced magnetic resonance imaging(MRI)is considered the gold standard technique in characterising focal liver lesions.Addition of gadoxetic acid has been shown to significantly increase diagnostic accuracy in the detection and characterization of liver abnormalities.Classic imaging characteristics of common liver lesions,including their behaviour on gadoxetic acid enhanced MRI,have been described in literature over recent years.It is important to be familiar with the typical aspects of these lesions as well as know the uncommon and overlapping imaging features to reach an accurate diagnosis.In this article,we will review the well-described characteristic imaging findings of common and rare focal liver lesions and present several challenging cases encountered in the clinical setting,namely hepatocellular adenoma,focal nodular hyperplasia,hepatic angiomyolipoma,hepatocellular carcinoma,intrahepatic cholangiocarcinoma,neuroendocrine tumours as well as a pleomorphic liposarcoma of the liver.

Clinical value of gadoxetic acid-enhanced magnetic resonance imaging in surgery for hepatocellular carcinoma- with a special emphasis on early hepatocellular carcinoma

Gadoxetic acid- or gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging(EOB-MRI) achieves excellent lesion detection and characterization for both hypervascular hepatocellular carcinoma(HCC) in arterial phase imagingand hypovascular early HCC(small well-differentiated HCC of the vaguely nodular type) in hepatobiliary phase imaging, and has become an indispensable imaging modality in the treatment of HCC. Early HCCs have been detected more frequently since the introduction of EOB-MRI into daily clinical practice. Early HCC is known to progress to conventional hypervascular HCC, and many risk factors have been identified for the hypervascularization of early HCC including the diameter of the tumor, presence of fat, and imaging findings of EOB-MRI. The rate of the development of hypervascular HCC was previously reported to be high in patients with chronic liver disease and early HCC. The presence of early HCC is regarded as a predictor for the recurrence of HCC following hepatic resection. On the other hand, although early HCC itself is currently not regarded as a target lesion for hepatic resection, early HCC at high risk of hypervascularity needs to be treated by local ablation therapy. If concomitant early HCC with progressed HCC is at high risk of hypervascularization and the functional liver reserve of a patient is sufficient, its simultaneous treatment at the time of hepatic resection for progressed HCC is recommended. Further studies on larger numbers of patients are needed before this strategy is adopted.

Optimal velocity encoding during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography

This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.

Diagnostic performance of abbreviated gadoxetic acid-enhanced magnetic resonance protocols with contrast-enhanced computed tomography for detection of colorectal liver metastases

BACKGROUND Although contrast-enhanced magnetic resonance imaging(MRI)using gadoxetic acid has been shown to have higher accuracy,sensitivity,and specificity for the detection and characterization of hepatic metastases compared with other modalities,the long examination time would limit the broad indication.Several abbreviated enhanced MRI(Ab-MRI)protocols without dynamic phases have been proposed to achieve equivalent diagnostic performance for the detection of colorectal liver metastases.However,an optimal protocol has not been established,and no studies have assessed the diagnostic performance of Ab-MRI combined with contrast-enhanced computed tomography(CE-CT),which is the preoperative imaging of colorectal cancer staging in clinical settings,to determine the best therapeutic strategy.AIM To compare the diagnostic performance of two kinds of Ab-MRI protocol with the standard MRI protocol and a combination of the Ab-MRI protocol and CE-CT for the detection of colorectal liver metastases.METHODS Study participants comprised 87 patients(51 males,36 females;mean age,67.2±10.8 years)who had undergone gadoxetic acid-enhanced MRI and CE-CT during the initial work-up for colorectal cancer from 2010 to 2021.Each exam was independently reviewed by two readers in three reading sessions:(1)Only single-shot fast spin echo(FSE)T2-weighted or fat-suppressed-FSE-T2-weighted,diffusion-weighted,and hepatobiliary-phase images(Ab-MRI protocol 1 or 2);(2)all acquired MRI sequences(standard protocol);and(3)a combination of an Ab-MRI protocol(1 or 2)and CE-CT.Diagnostic performance was then statistically analyzed.RESULTS A total of 380 Lesions were analyzed,including 195 metastases(51.4%).Results from the two Ab-MRI protocols were similar.The sensitivity,specificity,and positive and negative predictive values from Ab-MRI were non-inferior to those from standard MRI(P>0.05),while those from the combination of Ab-MRI protocol and CE-CT tended to be higher than those from Ab-MRI alone,although the difference was not significant(P>0.05),and were quite similar to those from standard MRI(P>0.05).CONCLUSION The diagnostic performances of two Ab-MRI protocols were non-inferior to that of the standard protocol.Combining Ab-MRI with CE-CT provided better diagnostic performance than Ab-MRI alone.

对比增强SWI对不同病理类型肺癌脑转移瘤的诊断价值

目的:探讨对比增强磁敏感加权成像(CE-SWI)与常规对比增强T 1WI成像(CE-T 1WI)对不同病理类型肺癌脑转移瘤的检出率差异,分析脑转移瘤内出现对比剂诱导相移(CIPS)与原发性肺癌病理类型间的关联性。方法:搜集经病理证实的79例原发性肺癌患者,其中腺癌组40例,鳞癌组18例,小细胞癌组21例,均行颅脑MR常规平扫、SWI、CE-T 1WI及CE-SWI检查,比较CE-SWI与CE-T 1WI检出的脑转移瘤数目及转移瘤内是否存在CIPS,转移灶经3个月后随访证实。结果:CE-T 1WI与CE-SWI对腺癌脑转移瘤的检出率差异有统计学意义(χ^(2)=5.05,P=0.025),对鳞癌(χ^(2)=0.00,P=1.000)与小细胞癌(χ^(2)=0.27,P=0.603)脑转移瘤的检出率差异无统计学意义。腺癌组、鳞癌组、小细胞癌组三组间CIPS阳性率差异有统计学意义(χ^(2)=11.13,P=0.004),其中鳞癌组与腺癌组(χ^(2)=11.08,P=0.001)、鳞癌组与小细胞癌组(χ^(2)=8.26,P=0.004)间差异有统计学意义,腺癌组与小细胞癌组间差异无统计学意义(χ^(2)=0.131,P=0.717)。结论:CE-SWI对肺腺癌脑转移瘤的检出较CE-T 1WI更有优势。肺腺癌、小细胞癌脑转移瘤的CIPS阳性率较鳞癌显著增高,CE-SWI可为肺癌脑转移瘤MRI检查常规序列的有利补充,为临床诊疗提供更多重要参考信息。

不同翻转角和延迟时间对Gd-BOPTA增强肝胆期肝脏和胆道系统图像质量的影响

目的探讨不同翻转角(flip angle,FA)和延迟时间对钆贝葡胺(gadobenate dimeglumine,Gd-BOPTA)增强MRI肝胆期(hepatobiliary phase,HBP)肝脏和胆道系统图像质量的影响。材料与方法回顾性分析57例肝脏Gd-BOPTA增强3.0 T MRI扫描患者病例。所有患者在注射对比剂后延迟60 min及120 min分别行FA为10°、15°、20°、25°、30°HBP成像,FA与延迟时间任意两两组合为10组。测量各组肝脏及胆总管的信号强度(signal intensity,SI)和竖脊肌的SI及标准差(standard deviation,SD),计算信噪比(signaltonoiseratio,SNR)、对比噪声比(contrast to noise ratio,CNR)、胆道-竖脊肌比值(bile to paravertebral muscle ratio,BMR);采用5分法对胆道的可视性进行主观评价。分别使用组内相关系数(intra-class correlation coefficient,ICC)和加权Kappa检验评估两名观察者间所测数据及主观评分的一致性;采用非参数Friedman检验进行各组SNR、CNR、BMR及主观评分多组间比较,采用LSD-t检验进行各组SNR、CNR、BMR及主观评分的事后组内两两比较,对结果进行Bonferroni校正,根据统计结果选择FA与延迟时间的最优组合。结果两名观察者除120min/FA15°组的SNR肝测量值的一致性为尚可外(ICC值=0.75),余各组数据测量及主观评分的一致性均良好(ICC值均>0.75,Kappa值均>0.75)。各参数在延迟120 min组均高于延迟60 min组;120min/FA30°组的SNR_(肝脏)最高[63.91(49.44,77.15)],与60min/FA10°组和120min/FA10°组的组间差异具有统计学意义(P<0.05);120min/FA30°组的CNR_(肝脏)最高[44.21(31.58,53.64)],与60min/FA10°组、60min/FA15°组、60min/FA30°组和120min/FA10°组的组间差异具有统计学意义(P<0.05);120min/FA30°组的SNR_(胆总管)最高[305.27(193.97,377.53)],与60min/FA10°组、60min/FA15°组、60min/FA20°组、60min/FA25°组、120min/FA10°组和120min/FA15°组的组间差异具有统计学意义(P<0.05);120min/FA30°组的CNR_(胆总管)最高[278.66(180.80,357.20)],与60min/FA10°组、60min/FA15°组、60min/FA20°组、60min/FA25°组、60min/FA30°组、120min/FA10°组、120min/FA15°组的组间差异具有统计学意义(P<0.05);120min/FA30°组的BMR最高[14.75(11.55,17.87)],与60min/FA10°组、60min/FA15°组、60min/FA20°组、60min/FA25°组、120min/FA10°组、120min/FA15°组的组间差异具有统计学意义(P<0.05)。主观评分结果显示,60min/FA10°组胆道的可视性最差,显著低于60min/FA20°组、60min/FA25°组、60min/FA30°组、120min/FA15°组、120min/FA20°组、120min/FA25°组、120min/FA30°组(P<0.05)。结论通过比较不同FA与延迟时间的组合,120min/FA30°组对Gd-BOPTA增强HBP肝脏及胆道图像质量显示最佳,增大FA与延长延迟时间可以明显提高图像质量。

心脏延迟增强MRI不同TI值对心肌梗死诊断效能的影响

目的:通过与TI值为300 ms的常规相位敏感反转恢复(PSIR)序列进行比较,探讨调整TI值为左室血池过零时PSIR序列心脏延迟增强MRI对心肌梗死的诊断效能。方法:将2022年3月-2022年12月在本院确诊为心肌梗死的35例患者纳入本研究。所有患者在静脉注射Gd-DTPA后10 min分别采用300 ms和血液过零时的TI值行PSIR序列延迟增强(LGE)扫描,扫描平面包括两腔心、四腔心及通过病变区的短轴位。测量并比较2种TI值LGE图像上正常心肌、心肌疤痕与心腔内血液的SNR、CNR和信号强度(SI)的差异及心肌梗死范围的差异。结果:调整TI后LGE图像上心肌疤痕区域与左心室血池的CNR[24.58(16.80,48.51)vs.11.83(5.04,22.73),Z=-6.87,P<0.05]更高,并能显示更大的梗死面积[4.20(2.10,7.55)mm^(2) vs.3.45(1.40,6.15)mm^(2),Z=-6.65,P<0.05],且有更高的疤痕-血池信号强度差[366.80(258.75,432.60)vs.175.90(73.30,259.35),Z=-8.13,P<0.05],更低的正常心肌-血池信号强度差[284.70(196.05,405.20)vs.511.20(394.55,636.70),Z=-8.07,P<0.01]。结论:调整TI后的PSIR序列心脏延迟增强扫描可以有效抑制心腔内血池信号,提高心肌疤痕与血池的对比,而且心内膜下和乳头肌的强化更明显而显示更清晰,从而可提高对梗死区域内心肌活性的检测敏感度。

4D flow技术在腹部应用的研究进展

腹部动脉、静脉或门静脉系统形态及功能改变与很多腹部疾病有关,因此腹部血流动力学的综合评估对很多临床诊治至关重要,但由于解剖学、正常生理学和各种病理异常的巨大复杂性而面临挑战。四维血流核磁共振(4D flow MRI)非常有效地结合了非侵入性及侵入性检查(如超声,血管造影,CT等)的优点,是一种新型的相位对比MRI技术,能全面无创的可视化和定量的评价腹部不同血管区域和器官中的腹部血流,同时有助于了解病理生理机制,是一种非常有潜力的全面评估腹部循环的技术。本文主要对4D flow技术在腹部中的应用进展进行综述,为临床对疾病的诊断和治疗以及科研提供新的方向和思路。

四维血流磁共振成像在门静脉系统中的应用现状

磁共振成像在门静脉系统中的应用越来越受到重视,而四维血流磁共振成像作为一种新型磁共振技术,可以动态显示血管内血流动力学的变化。目前,该技术已广泛应用于全身各个血管系统检查中,其可以从形态学和血流动力学两方面对血流进行定性和定量分析,对疾病的诊断及其严重程度的判断具有重要意义。本文就四维血流磁共振成像在门静脉系统中的临床应用现状进行简要综述。

钆塞酸二钠增强MRI在结直肠癌肝转移术前评估中的价值

目的探讨钆塞酸二钠(Gd-EOB-DTPA)增强MRI对结直肠癌肝转移(CRCLM)术前评估的临床价值。资料与方法收集2019年9月—2023年3月河南中医药大学第一附属医院56例CRCLM患者,经手术病理确诊共156个CRCLM病灶,均行肝脏Gd-EOB-DTPA动态增强MRI检查。观察T2WI、扩散加权成像(DWI)、动脉期和肝胆期(HBP)的特征表现,并计算各序列的检出率,计算HBP病灶与肝实质信号强度比和表观扩散系数(ADC)。比较HBP呈反靶征、靶征的病灶与HBP呈均匀、不均匀低信号病灶的ADC值和各序列检出率的差异。结果20.51%(32/156)的病灶T2WI呈靶样外观、38.46%(60/156)呈均匀高信号,51.28%(80/156)的病灶DWI呈靶征,73.72%(115/156)动脉期呈环形强化,34.62%(54/156)HBP呈靶征。HBP呈反靶征、靶征病灶与HBP呈均匀、不均匀低信号病灶的平均ADC值比较,差异无统计学意义[(0.98±0.43)×10^(-3)mm^(2)/s比(1.01±0.47)×10^(-3)mm^(2)/s;t=-0.340,P=0.327]。依据CRCLM的病灶大小分为<1.0 cm、1.0~2.0 cm和>2.0 cm组,分别有41、55、60个病灶。与T2WI、DWI、Gd-EOB-DTPA四期动态增强比较,HBP的总检出率(96.79%)最高(P均<0.05)。当CRCLM病灶<1.0 cm时,HBP的检出率(87.80%)高于T2WI、DWI和Gd-EOB-DTPA四期动态增强的检出率(P均<0.05)。结论GdEOB-DTPA增强MRI对CRCLM术前评估具有重要临床价值,尤其是特异性的HBP靶征或反靶征,以及HBP对CRCLM微小病灶优异的检出效能。

相位对比电影MRI及术中超声在Chiari畸形1型手术方式选择中的临床应用进展

枕大孔减压术是治疗Chiari畸形1型(CM1)患者的通用手术,但减压范围、临床疗效存在争议,没有单一、明确的治疗方法。脑脊液流体动力学的改善可能与临床症状的缓解有关,相位对比电影MRI(PC-MRI)联合术中超声(IOUS)可以准确评估颅颈交界区的脑脊液流体动力学改变,两者结合可以为损害程度评估提供有效信息,指导手术方式的选择,预测临床改善效果,减少再手术的发生。本文对PC-RMI联合IOUS在CM1术式选择中的临床应用进行综述。

高b值弥散加权成像在缺血性中风超急性期诊断中的价值

目的探讨高b值磁共振弥散加权成像(DWI)及表观弥散系数(ADC)值在缺血性中风(AIS)超急性期(发病时间<6 h)诊断中的应用价值,以期为临床治疗提供参考。方法选取2020年6月—2023年2月在重庆市北碚区中医院经临床确诊和治疗痊愈或好转的AIS超急性期患者34例为研究对象。34例患者均完成高b值(b值=2000 s/mm^(2))、常规b值(b值=1000 s/mm^(2))DWI扫描,将2组DWI图像分为高b值组和常规b值组,分析2组图像的DWI影像特点,并对ADC图进行定量分析。结果高、常规b值组显示病灶分别为98、74个。所研究病例T1WI均呈等或稍低信号、T2WI和T2-Flair呈等或稍高信号,无特异性;高b值组病灶DWI呈中等、明显高信号,常规b值组病灶DWI呈轻度、中等高信号,且高b值组病灶边界显示更清楚。高、常规b值组图像的ADC值比较,病变区ADC值在高b值组更低,2组差异有统计学意义(P<0.05),健侧对称区ADC值也在高b值组更低,2组差异也具有统计学意义(P<0.05);同一b值下的ADC值比较,病变区与健侧对称区ADC值差异均具有统计学意义(P<0.05)。高b值组图像敏感度为100.0%,特异度为82.4%;常规b值组,敏感度为100.0%,特异度为76.5%。高b值组图像SNR、CNR均高于常规b值组,差异均有统计学意义(P<0.05)。结论在临床工作中,采用高b值DWI扫描可以提高AIS超急性期病灶的检出率,并且能使病灶影像质量达到更佳的效果。所以,高b值DWI对超急性期AIS的诊断价值优于常规b值DWI,可能值得临床运用推广。

磁共振弥散加权成像联合磁敏感加权成像检查在急性期脑出血诊断中的效能

目的:观察磁共振弥散加权成像(DWI)联合磁敏感加权成像(SWI)检查在急性期脑出血诊断中的效能。方法:选取2021年1月至2023年1月该院收治的99例疑似急性期脑出血患者为研究对象,均进行DWI、SWI序列扫描,以手术结果为金标准,比较DWI、SWI单项及联合检查在急性期脑出血诊断中的效能及其影像学特征。结果:99例疑似急性期脑出血患者中,手术结果确诊阳性48例,阴性51例;DWI检查确诊阳性27例,阴性72例;SWI检查确诊阳性44例,阴性55例;DWI联合SWI检查确诊阳性48例,阴性51例;DWI联合SWI检查诊断急性期脑出血的灵敏度、准确度、阴性预测值均高于DWI、SWI单项检查,差异有统计学意义(P<0.05);DWI、SWI检查急性期脑出血患者均表现为血肿中心极低信号,周围高信号,边缘较清的影像学特征。结论:DWI联合SWI检查诊断急性期脑出血的效能高于二者单项检查。