Diffusion weighted magnetic resonance imaging (DWI) is an imaging technique which provides tissue contrast by the measurement of diffusion properties of water molecules within tissues. Diffusion is expressed in an app...Diffusion weighted magnetic resonance imaging (DWI) is an imaging technique which provides tissue contrast by the measurement of diffusion properties of water molecules within tissues. Diffusion is expressed in an apparent diffusion coefficient (ADC), which reflects the diffusion properties unique to each type of tissue. DWI has been originally used in neuroradiology. More recently, DWI has increasingly been used in addition to conventional unenhanced and enhanced magnetic resonance imaging (MRI) in other parts of the body. The reason for this delay was a number of technical problems inherent to the technique, making DWI very sensitive to artifacts, which had to be overcome. With assessment of ADC values, DWI proved to be helpful in characterization of focal liver lesions. However, DWI should always be used in conjunction to conventional MRI since there is considerable overlap between ADC values of benign and malignant lesions. DWI is useful in the detection of hepatocellular carcinoma in the cirrhotic liver and detection of liver metastases in oncological patients. In addition, DWI is a promising tool in the prediction of tumor responsiveness to chemotherapy and the follow-up of oncological patients after treatment, as DWI may be capable of detecting recurrent disease earlier than conventional imaging.This review focuses on the most common applications of DWI in the liver.展开更多
Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolle...Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolled in our study. All the patients received the whole body DWI and bone scintigraphy scan within 1 week. The magnetic resonance (MR) examination was performed on 3.0T MR scanner using embedded body coil. The images were reviewed separately by two radiologists and two nuclear medicine physicians, who were blinded to the results of the other imaging modality. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the two techniques for detecting bone metastasis were analyzed. Results A total of 181 metastatic lesions in 77 regions of 34 patients were detected by whole body DWI, and 167 metastatic lesions in 76 regions of 31 patients were identified by bone scintigraphy. The patient-based sensitivity and PPV of whole body DWI and bone scintigraphy were similar (89.5% vs. 81.6%, 97.1% vs. 91.2%), whereas, the patient-based specificity and NPV of whole body DWI were obviously higher than those of bone scintigraphy (85.7% vs. 57.1%, 60.0% vs. 36.4%). Ten regions negative in scintigraphy but positive in whole body DWI, mainly located in spine, pelvis, and femur; nine regions only detected by scintigraphy, mainly located in skull, sternum, clavicle, and scapula. The region-based sensitivity and specificity of whole body DWI were slightly higher than those of bone scintigraphy (89.5% vs. 88.4%, 95.6% vs. 87.6%). Conclusion Whole body DWI reveals excellent concordance with bone scintigraphy regarding detection of bone metastasis, and the two techniques are complementary for each other.展开更多
Objective To evaluate the values of whole body diffusion weighted imaging （DWI） in screenmg pnmary unknown tumor in patients with metastases. Methods Totally, 34 patients with metastases of primary unknown tumors w...Objective To evaluate the values of whole body diffusion weighted imaging （DWI） in screenmg pnmary unknown tumor in patients with metastases. Methods Totally, 34 patients with metastases of primary unknown tumors were scanned with whole body DWI, and conventional magnetic resonance （MR） imaging was performed if suspected lesions were detected. All the metastases including 27 cases of osseous metastases, 2 brain metastases, 2 liver metastases, 1 pulmonary multiple metastasis, 1 neck metastasis and 1 malignant ascites, were diagnosed by computed tomography, single photon emission computed tomography, or MR imaging. For the proven primary tumors diagnosed by biopsy or pathology of surgical specimens, apparent diffusion coefficient （ADC） values of the primary and metastatic lesions were measured respectively. The sensitivity and specificity of this technique for screening primary tumors were cvaluated. Results We found 24 cases with suspected primary lesions, in which 23 lesions were proved to be primary tumors, and 1 was proved to be benign lesion. And no definite primary lesion was found in 10 cases on whole body DWI, but in which 1 case was diagnosed with primary tumor by biopsy later, and the other 9 cases remained unknown within follow-up of over halfa year. The difference was not significant in ADC values between primary and metastatic lesions （P〉0.05）. The sensitivity and specificity of whole body DWI for searching primary tumors was 95.8% and 90.0%, respectively. Conclusion Combined with conventional MR scanning, whole body DWI can help to search primary lesions of patients with metastases.展开更多
AIM:To retrospectively and prospectively compare diffusion-weighted(DW)images in the abdomen in a1.5T system and 3.0T systems with and without twochannel functionality for B1shimming.METHODS:DW images of the abdomen w...AIM:To retrospectively and prospectively compare diffusion-weighted(DW)images in the abdomen in a1.5T system and 3.0T systems with and without twochannel functionality for B1shimming.METHODS:DW images of the abdomen were obtained on 1.5T and 3.0T(with and without two-channel functionality for B1shimming)scanners on 150 patients(retrospective study population)and 10 volunteers(prospective study population).Eight regions were selected for clinical significance or artifact susceptibility(at higher field strengths).Objective grading quantified signal-to-noise ratio(SNR),and subjective evaluation qualified image quality,ghosting artifacts,anddiagnostic value.Statistical significance was calculated usingχ2tests(categorical variables)and independent two-sided t tests or Mann-Whitney U tests(continuous variables).RESULTS:The 3.0T using dual-source parallel transmit(dpTX 3.0T)provided the significantly highest SNRs in nearly all regions.In regions susceptible to artifacts at higher field strengths(left lobe of liver,head of pancreas),the SNR was better or similar to the 1.5T system.Subjectively,both dpTX 3.0T and 1.5T systems provided higher image quality,diagnostic value,and less ghosting artifact(P【0.01,most values)compared to the 3.0T system without dual-source parallel transmit(non-dpTX 3.0T).CONCLUSION:The dpTX 3.0T scanner provided the highest SNR.Its image quality,lack of ghosting,and diagnostic value were equal to or outperformed most currently used systems.展开更多
Diffusion-weighted magnetic resonance imaging(DWI) provides image contrast that is different from that obtained by conventional magnetic resonance techniques.Although previously,DWI has been used to evaluate various d...Diffusion-weighted magnetic resonance imaging(DWI) provides image contrast that is different from that obtained by conventional magnetic resonance techniques.Although previously,DWI has been used to evaluate various diseases of the central nervous system,several technical advances have expanded the clinical applications of DWI beyond the central nervous system.As a result,many reports have been published on the use of DWI in abdominal diseases.Particularly,abdominal DWI has now being focused on evaluation of patients with abdominal cancer.DWI can be used for pretreatment tumor detection,characterization including predicting tumor response to therapy,monitoring tumor response during therapy,and follow-up study after treatment to detect possible tumor recurrence.展开更多
目的 探讨非对称回波最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo asymmetrical and least-squares estimation quantitation sequence, IDEAL-IQ)来源的R2^(*)值在乳腺良恶性肿瘤鉴别诊断中...目的 探讨非对称回波最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo asymmetrical and least-squares estimation quantitation sequence, IDEAL-IQ)来源的R2^(*)值在乳腺良恶性肿瘤鉴别诊断中的价值,并与传统多回波T2^(*)梯度回波(gradient recalled echo, GRE)序列来源的R2^(*)值进行比较。材料与方法 回顾性分析2021年9月至2023年10月在中国医科大学附属第一医院连续收治的42名患者的50个良性肿瘤病灶,在本院影像归档和通信系统(picture archiving and communication systems, PACS)中使用倾向性评分匹配方法匹配肿瘤所在最大层面的最长径,按1∶3的比例纳入150名患者的150个恶性肿瘤病灶。将恶性肿瘤根据预后因子[雌激素受体(estrogen receptor, ER)、孕激素受体(progesterone receptor, PR)以及人表皮生长因子受体2(human epidermal growth factor receptor 2, HER-2)]的阳性/阴性表达情况进行分组。所有患者均接受包含IDEAL-IQ和多回波T2*GRE序列的多参数MRI,测量以下定量参数:IDEAL-IQ序列R2^(*)值(R2^(*)IDEAL)、多回波T2*GRE序列R2^(*)值(R2^(*)GRE)、表观扩散系数(apparent diffusion coefficient, ADC)及肿瘤长径。根据原始资料类型的不同,分别利用单因素分析(独立样本t检验、Mann-Whitney U检验等方法)对比分析各参数的差异。采用Spearman相关性分析R2^(*)IDEAL与R2^(*)GRE及二者与ADC的相关性。采用配对样本t检验比较R2^(*)IDEAL与R2^(*)GRE的差异。采用logistic回归分析建立联合诊断模型,并使用受试者工作特征(receiver operating characteristic, ROC)曲线及曲线下面积(area under the curve,AUC)分析单独及联合参数鉴别乳腺肿瘤良恶性的效能。结果 相关性分析显示乳腺肿瘤患者的R2^(*)IDEAL与R2^(*)GRE呈中度相关(r=0.763,P<0.001),二者与ADC值均呈负性弱相关[r=-0.300(R2^(*)IDEAL),-0.306(R2^(*)GRE),P<0.001]。良性组与恶性组中,R2^(*)IDEAL与R2^(*)GRE均呈中度相关(r=0.745、0.680,P<0.001),二者与ADC均无相关性。两种序列所得的R2^(*)值差异有统计学意义(P<0.001)。R2^(*)IDEAL在良恶性组间差异有统计学意义(P<0.001),管腔HER-2阴性型R2^(*)值最高。对于单一参数,ADC值鉴别良恶性的AUC最高(0.857);对于联合参数,R2^(*)IDEAL+ADC鉴别良性组与管腔阴性组的AUC最高(0.927);差异均有统计学意义(P<0.05)。结论 IDEAL-IQ序列生成的R2^(*)值可用于区分良恶性乳腺肿块,可能成为除ADC外辅助乳腺肿瘤良恶性鉴别的又一无需对比剂参数。展开更多
文摘Diffusion weighted magnetic resonance imaging (DWI) is an imaging technique which provides tissue contrast by the measurement of diffusion properties of water molecules within tissues. Diffusion is expressed in an apparent diffusion coefficient (ADC), which reflects the diffusion properties unique to each type of tissue. DWI has been originally used in neuroradiology. More recently, DWI has increasingly been used in addition to conventional unenhanced and enhanced magnetic resonance imaging (MRI) in other parts of the body. The reason for this delay was a number of technical problems inherent to the technique, making DWI very sensitive to artifacts, which had to be overcome. With assessment of ADC values, DWI proved to be helpful in characterization of focal liver lesions. However, DWI should always be used in conjunction to conventional MRI since there is considerable overlap between ADC values of benign and malignant lesions. DWI is useful in the detection of hepatocellular carcinoma in the cirrhotic liver and detection of liver metastases in oncological patients. In addition, DWI is a promising tool in the prediction of tumor responsiveness to chemotherapy and the follow-up of oncological patients after treatment, as DWI may be capable of detecting recurrent disease earlier than conventional imaging.This review focuses on the most common applications of DWI in the liver.
文摘Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolled in our study. All the patients received the whole body DWI and bone scintigraphy scan within 1 week. The magnetic resonance (MR) examination was performed on 3.0T MR scanner using embedded body coil. The images were reviewed separately by two radiologists and two nuclear medicine physicians, who were blinded to the results of the other imaging modality. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the two techniques for detecting bone metastasis were analyzed. Results A total of 181 metastatic lesions in 77 regions of 34 patients were detected by whole body DWI, and 167 metastatic lesions in 76 regions of 31 patients were identified by bone scintigraphy. The patient-based sensitivity and PPV of whole body DWI and bone scintigraphy were similar (89.5% vs. 81.6%, 97.1% vs. 91.2%), whereas, the patient-based specificity and NPV of whole body DWI were obviously higher than those of bone scintigraphy (85.7% vs. 57.1%, 60.0% vs. 36.4%). Ten regions negative in scintigraphy but positive in whole body DWI, mainly located in spine, pelvis, and femur; nine regions only detected by scintigraphy, mainly located in skull, sternum, clavicle, and scapula. The region-based sensitivity and specificity of whole body DWI were slightly higher than those of bone scintigraphy (89.5% vs. 88.4%, 95.6% vs. 87.6%). Conclusion Whole body DWI reveals excellent concordance with bone scintigraphy regarding detection of bone metastasis, and the two techniques are complementary for each other.
文摘Objective To evaluate the values of whole body diffusion weighted imaging （DWI） in screenmg pnmary unknown tumor in patients with metastases. Methods Totally, 34 patients with metastases of primary unknown tumors were scanned with whole body DWI, and conventional magnetic resonance （MR） imaging was performed if suspected lesions were detected. All the metastases including 27 cases of osseous metastases, 2 brain metastases, 2 liver metastases, 1 pulmonary multiple metastasis, 1 neck metastasis and 1 malignant ascites, were diagnosed by computed tomography, single photon emission computed tomography, or MR imaging. For the proven primary tumors diagnosed by biopsy or pathology of surgical specimens, apparent diffusion coefficient （ADC） values of the primary and metastatic lesions were measured respectively. The sensitivity and specificity of this technique for screening primary tumors were cvaluated. Results We found 24 cases with suspected primary lesions, in which 23 lesions were proved to be primary tumors, and 1 was proved to be benign lesion. And no definite primary lesion was found in 10 cases on whole body DWI, but in which 1 case was diagnosed with primary tumor by biopsy later, and the other 9 cases remained unknown within follow-up of over halfa year. The difference was not significant in ADC values between primary and metastatic lesions （P〉0.05）. The sensitivity and specificity of whole body DWI for searching primary tumors was 95.8% and 90.0%, respectively. Conclusion Combined with conventional MR scanning, whole body DWI can help to search primary lesions of patients with metastases.
文摘AIM:To retrospectively and prospectively compare diffusion-weighted(DW)images in the abdomen in a1.5T system and 3.0T systems with and without twochannel functionality for B1shimming.METHODS:DW images of the abdomen were obtained on 1.5T and 3.0T(with and without two-channel functionality for B1shimming)scanners on 150 patients(retrospective study population)and 10 volunteers(prospective study population).Eight regions were selected for clinical significance or artifact susceptibility(at higher field strengths).Objective grading quantified signal-to-noise ratio(SNR),and subjective evaluation qualified image quality,ghosting artifacts,anddiagnostic value.Statistical significance was calculated usingχ2tests(categorical variables)and independent two-sided t tests or Mann-Whitney U tests(continuous variables).RESULTS:The 3.0T using dual-source parallel transmit(dpTX 3.0T)provided the significantly highest SNRs in nearly all regions.In regions susceptible to artifacts at higher field strengths(left lobe of liver,head of pancreas),the SNR was better or similar to the 1.5T system.Subjectively,both dpTX 3.0T and 1.5T systems provided higher image quality,diagnostic value,and less ghosting artifact(P【0.01,most values)compared to the 3.0T system without dual-source parallel transmit(non-dpTX 3.0T).CONCLUSION:The dpTX 3.0T scanner provided the highest SNR.Its image quality,lack of ghosting,and diagnostic value were equal to or outperformed most currently used systems.
文摘Diffusion-weighted magnetic resonance imaging(DWI) provides image contrast that is different from that obtained by conventional magnetic resonance techniques.Although previously,DWI has been used to evaluate various diseases of the central nervous system,several technical advances have expanded the clinical applications of DWI beyond the central nervous system.As a result,many reports have been published on the use of DWI in abdominal diseases.Particularly,abdominal DWI has now being focused on evaluation of patients with abdominal cancer.DWI can be used for pretreatment tumor detection,characterization including predicting tumor response to therapy,monitoring tumor response during therapy,and follow-up study after treatment to detect possible tumor recurrence.
