Correlation of apparent diffusion coefficient measured by diffusion-weighted MRI and clinicopathologic features in pancreatic cancer patients

Background/purpose

The aim of this study was to evaluate the clinical usefulness of diffusion-weighted magnetic resonance imaging (DWI) in patients with pancreatic cancer by comparing the apparent diffusion coefficient (ADC) value with clinicopathologic features.

Methods

Twenty-two consecutive patients (12 men, 10 women; mean age 64.4 years) with pancreatic cancer underwent DWI before surgery. We retrospectively investigated the correlations between tumor ADC value and clinicopathologic features.

Results

Apparent diffusion coefficient value was significantly lower for pancreatic cancer than for noncancerous tissue (P < 0.001). Receiver operating characteristic analysis yielded an optimal ADC cutoff value of 1.21 × 10^?3 mm²/s to distinguish pancreatic cancer from noncancerous tissue. There was a significant negative correlation between ADC value and tumor size (r = ?0.59, P = 0.004) and between ADC value and number of metastatic lymph nodes (r = ?0.56, P = 0.007). Tumors with low ADC value had a significant tendency to show high portal venous system invasion (P = 0.02) and extrapancreatic nerve plexus invasion (P = 0.01).

Conclusions

Apparent diffusion coefficient value appears to be a promising parameter for detecting pancreatic cancer and evaluating the degree of malignancy of pancreatic cancer.     

Testicular tumors: discriminative value of conventional MRI and diffusion weighted imaging

To explore the feasibility of using conventional MRI features combined with apparent diffusion coefficient (ADC) values for the differential diagnosis of testicular tumors.A total of 63 patients with pathologically confirmed testicular tumors were enrolled in this study. In particular, there were 46 cases of malignant lesions and 17 cases of benign lesions. All patients underwent conventional magnetic resonance imaging (MRI) and diffusion weighted imaging. Multivariate logistic regression models and receiver operating characteristic curves were constructed to assess diagnostic accuracies.T2-homogeneity, intratumoral septa, and peritumoral infiltration were more common in the malignant group, and capsule sign was more common in the benign group (P < .05 for all). The mean ADC value of the malignant group was lower than that of the benign group (P < .05). When the ADC value ≤ 0.90 × 10⁻³ mm²/s, the diagnosis tended to be malignancy. The conventional MRI model could achieve better diagnostic accuracy than ADC values alone (P < .05). Compared with the conventional MRI model, the specificity and accuracy of the full model (ADC and conventional MRI model) increased by 9.8% and 3.2%, respectively. T2-homogeneity and T2-hypointensity were more common in seminoma and lymphoma, cystic changes were more common in nonseminomatous germ cell tumor (NSGCT), and intratumoral septa was more common in seminoma (P < .05 for all). The ADC value of NSGCT was larger than seminoma, and lymphoma was the smallest (P < .05 for all). Cystic changes, T2-hypointensity, intratumoral septa, and ADC value were independent factors for differentiating the seminoma, NSGCT, and lymphoma subgroups.A combination of conventional MRI features and ADC values can improve the diagnostic efficiency for differentiating benign and malignant testicular tumors, and can additionally distinguish different subtypes of malignant testicular tumors.     

Diagnostic value of diffusion-weighted magnetic resonance imaging compared with fluorodeoxyglucose positron emission tomography/computed tomography for pancreatic malignancy: a meta-analysis using a hierarchical regression model

Background and Aim: To obtain diagnostic performance of diffusion‐weighted magnetic resonance imaging (DWI) and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the detection of pancreatic malignancy. Methods: We performed a meta‐analysis of all available studies of the diagnostic performance of DWI and PET/CT for pancreatic malignancy. MEDLINE, EMBASE, Cochrane library and some other databases were searched for initial studies. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR?), and constructed summary receiver operating characteristic curves (SROC) using hierarchical regression models. Results: Across 16 studies with 804 patients, PET/CT sensitivity was 0.87 (95% confidence interval [CI], 0.82, 0.81) and specificity was 0.83 (95% CI, 0.71, 0.91). Overall, LR+ was 5.84 (95% CI, 4.59, 7.42) and LR? was 0.24 (95% CI, 0.17, 0.33). DWI sensitivity was 0.85 (95% CI, 0.74, 0.92) and specificity was 0.91 (95% CI, 0.71, 0.98). LR+ was 9.53 (95% CI, 2.41, 37.65) and LR? was 0.17 (95% CI, 0.09, 0.32). In subgroup analysis, the sensitivity of enhanced versus unenhanced PET/CT in the detection of pancreatic cancer was 0.91 (95% CI, 0.86, 0.96) versus 0.84 (95% CI, 0.78, 0.90) (P > 0.05), the specificity 0.88 (95% CI, 0.73, 1.00) versus 0.81 (95% CI, 0.69, 0.94) (P > 0.05). Conclusion: Positron emission tomography/computed tomography (PET/CT) was highly sensitive and DWI was a highly specific modality in diagnosing patients with pancreatic malignancy. PET/CT and DWI could play different roles in diagnosing pancreatic carcinoma. Enhanced PET/CT seems to be superior to unenhanced PET/CT. Further larger prospective studies are needed to establish its value for diagnosis in pancreatic cancer.     

磁共振弥散加权成像对胰腺癌与慢性肿块型胰腺炎的鉴别诊断价值

目的 比较磁共振弥散加权成像(diffusion-weighted imaging,DWI)对胰腺癌与慢性肿块型胰腺炎的鉴别能力.方法 对38例胰腺癌、9例肿块型CP、15例正常胰腺行DWI.在x、Y、Z轴3个方向上选择3个不同弥散系数(b=0、500、1 000 s/mm2)进行扫描,共行2次DWI.根据表观弥散系数(apparent diffusion coefficient,ADC)图像测量ADC值.结果 38例胰腺癌平均ADC值为(1.411±0.101)×10m-3mm2/s,9例肿块型CP的平均ADC值为(1.053±0.113)×10-3mm2/s,15例正常胰腺平均ADC值为(1.245±0.112)×10-3mm2/s,两两比较均有统计学意义(P＜0.05).结论 DWI可对胰腺癌与肿块型CP进行鉴别诊断,具有较大的临床意义.     

多b值弥散加权磁共振成像在老年原发性中枢神经系统淋巴瘤患者预后评估中的应用价值

目的 探讨多b值弥散加权磁共振成像(multi-b-value diffusion-weighted magnetic resonance imaging,eDWI-MRI)参数及临床特征在老年原发性中枢神经系统淋巴瘤(primary central nervous system lymphoma,PCNSL)患者预后...     

Diagnosis value preoperative localization of insulinoma by diffusion-weighted imaging: A pilot study

Insulinoma is the most common functional neuroendocrine tumor that originates from the islet of beta cells. Insulinoma is usually an isolated benign tumor and small in size (<2 cm). Due to the small size of the lesion, it often leads to difficulty in clinical preoperative localization diagnosis. However, we have unexpectedly discovered that the diffusion-weighted-imaging (DWI) adds great value in the preoperative localization diagnosis of insulinoma in non-invasive examination technique.We verified using operative pathology data and retrospectively analyzed the clinical and imageology findings of 5 cases who reported to have an insulinoma. All the 5 cases underwent DWI examination, among non-contrast enhanced magnetic resonance imaging (MRI) in 1 case, contrast-enhanced MRI in 4 cases.Five cases of DWI showed a nodular high signal <1.3 cm with pancreatic tail in 3 cases, pancreatic neck, and pancreatic head in 1 case each, respectively. Non-contrast enhanced MRI showed suspicious abnormal signals in the tail of the pancreas were detected in 1 case. MRI enhanced scans presented 2 cases with abnormal enhancement in the arterial phase and 2 cases without abnormal enhancement in arterial phase. Also, 3 cases showed mild persistence enhanced in the portal venous phase and delayed phase. However, 1 case remained normal in the portal venous phase and the delay period.DWI examination has high clinical value in the localization diagnosis of insulinoma and thus it can be used as a routine examination for preoperative localization diagnosis.     

Importance of b value in diffusion weighted imaging for the diagnosis of pancreatic cancer

AIM:To investigate the use of multi-b-value diffusionweighted imaging in diagnosing pancreatic cancer.METHODS:We retrospectively analyzed 33 cases of pancreatic cancer and 12 cases of benign pancreatic tumors at the Second Affiliated Hospital of Kunming Medical University from December 2008 to January2011.The demographic characteristics,clinical presentation,routine magnetic resonance imaging and diffusion weighted imaging(DWI)features with different b values were reviewed.Continuous data were expressed as mean±SD.Comparisons between pancreatic cancer and benign pancreatic tumors were performed using the Student’s t test.A probability of P<0.05 was considered statistically significant.RESULTS:Thirty-three patients with pancreatic cancer were identified.The mean age at diagnosis was 60±5.6 years.The male:female ratio was 21:12.Twenty cases were confirmed by surgical resection and 13 by biopsy of metastases.T1 weighted images demonstrated a pancreatic head mass in 16 patients,a pancreatic body mass in 10 cases,and a pancreatic tail mass with pancreatic atrophy in 7 cases.Eight patients had hepatic metastases,13 had invasion or envelopment of mesenteric vessels,4 had bone metastases,and 8had lymph node metastases.DWI demonstrated an irregular intense mass with unclear margins.Necrotic tissue demonstrated an uneven low signal.A b of 1100s/mm2was associated with a high intensity signal with poor anatomical delineation.A b of 700 s/mm2was associated with apparent diffusion coefficients(ADCs)that were useful in distinguishing benign and malignant pancreatic tumors(P<0.05).b values of 50,350,400,450 and 1100 s/mm2were associated with ADCs that did not differentiate the two tumors.CONCLUSION:Low b value images demonstrated superior anatomical details when compared to high b value images.Tumor tissue definition was high and contrast with the surrounding tissues was good.DWI was useful in diagnosing pancreatic cancer.     

磁共振弥散加权成像对肾癌与肾血管平滑肌脂肪瘤的诊断价值

目的探讨磁共振弥散加权成像对肾癌和肾血管平滑肌脂肪瘤的诊断价值。方法选取85例肾肿瘤患者（包括肾癌54例,肾血管平滑肌脂肪瘤31例）,术前行常规MRI平扫检查及弥散加权成像,并在取b值为800 s/mm2时直接测量肾脏肿瘤实性部分的平均表观弥散系数（ADC）值。结果 54例肾癌肿瘤实性部分在弥散加权成像上表现为高信号;31例肾血管平滑肌脂肪瘤表现为边界清楚的混杂信号,其中软组织部分呈等、稍高信号,脂肪部分呈低信号。在b值取800 s/mm2时,肾癌、血管平滑肌脂肪瘤的ADC值比较差异具有统计学意义（P〈0.05）。结论通过弥散加权成像及ADC值,可以更多了解肿瘤的内部结构,有助于肾脏良恶性肿瘤的诊断和鉴别诊断。     

磁共振成像评价常压高浓度氧对大鼠脑缺血的保护作用

目的利用磁共振弥散加权成像(DWI)评价常压高浓度氧(NBO)对大鼠脑缺血的保护作用。方法选择雄性SD大鼠16只,采用线栓法制作右侧大脑中动脉闭塞脑缺血模型,随机分为NBO组和对照组,每组8只。分别于2 h和24 h行头颅MRI扫描。冠状位DWI测量大鼠的脑梗死体积及增大率;在脑梗死最大层面的表观扩散系数(ADC)图上测量脑梗死中心区和边缘区的ADC值,并计算ADC值的降低率。取脑行HE染色,并与DWI结果进行比较。结果 NBO组与对照组大鼠右侧大脑中动脉供血区异常高信号,ADC图上为低信号。NBO组大鼠2h和24 h脑梗死体积增大率均低于对照组,但差异无统计学意义(P>0.05)。NBO组大鼠2 h和24 h梗死中心区ADC值降低率与对照组差异无统计学意义(P>0.05);而NBO组梗死边缘区ADC值降低率明显小于对照组(P<0.01)。NBO组与对照组大鼠HE染色脑梗死灶与相应DWI层面差异无统计学意义(P>0.05)。结论 DWI显示NBO对大鼠脑缺血有保护作用。     

Acute pancreatitis successfully diagnosed by diffusion-weighted imaging： A case report

Diffusion-weighted imaging （DWI） is an established diagnostic method of acute stroke. The latest advances in magnetic resonance imaging （MRI） technology have greatly expanded the utility of DWI in the examination of various organs. Recent studies have revealed the usefulness of DWI for imaging of the liver, kidney, ovary, and breast. We report a patient with acute pancreatitis detected by DWI and discussed the efficacy of DWI in diagnosing acute pancreatitis. A 50-year old man presented with a primary complaint of abdominal pain. We performed both DWI and computed tomography （CT） for this patient. The signal intensity in a series of DWI was measured and the apparent diffusion coefficient （ADC） values were calculated to differentiate inflammation from normal tissue. Two experienced radiologists evaluated the grade of acute pancreatitis by comparing the CT findings. Initially, the pancreas and multiple ascites around the pancreas produced a bright signal and ADC values were reduced on DWI. As the inflammation decreased, the bright signal faded to an iso-signal and the ADC values returned to their normal level. There was no difference in the abilities of DWI and CT images to detect acute pancreatitis. However, our case indicates that DWI can evaluate the manifestations of acute pancreatitis using no enhancement material and has the potential to replace CT as a primary diagnostic strategy for acute pancreatitis.     

Morphological and functional evaluation of chronic pancreatitis with magnetic resonance imaging

Magnetic resonance imaging(MRI)techniques for assessment of morphology and function of the pancreas have been improved dramatically the recent years and MRI is very often used in diagnosing and follow-up of chronic pancreatitis(CP)patients.Standard MRI including fat-suppressed T1-weighted and T2-weighted imaging techniques reveal decreased signal and glandular atrophy of the pancreas in CP.In contrast-enhanced MRI of the pancreas in CP the pancreatic signal is usually reduced and delayed due to decreased perfusion as a result of chronic inflammation and fibrosis.Thus,morphological changes of the ductal system can be assessed by magnetic resonance cholangiopancreatography(MRCP).Furthermore,secretin-stimulated MRCP is a valuable technique to evaluate side branch pathology and the exocrine function of the pancreas and diffusion weighted imaging can be used to quantify both parenchymal fibrotic changes and the exocrine function of the pancreas.These standard and advanced MRI techniques are supplementary techniques to reveal morphological and functional changes of the pancreas in CP.Recently,spectroscopy has been used for assessment of metabolite concentrations in-vivo in different tissues and may have the potential to offer better tissue characterization of the pancreas.Hence,the purpose of the present review is to provide an update on standard and advanced MRI techniques of the pancreas in CP.     

Role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of focal hepatic lesions

AIM: To evaluate the utility of diffusion-weighted imaging (DWI) in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS: Magnetic resonance imaging (MRI) examinations were performed using the Signa Excite Xl Twin Speed 1.5T system (GE Healthcare, Milwaukee, WI, USA). Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas (HCC), four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio (RCR), and apparent diffusion coefficient (ADC) were compared between benign and malignant lesions on DWI. Superparamagnetic iron oxide (SPIO) was administered to 59 patients, and RCR was compared pre- and postadministration. RESULTS: DWI showed higher contrast between malignant lesions (especially in multiple small metastatic cancers) and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs (mean ± SD × 10~(-3) mm~2/s) were significantly lower ( P < 0.05) in malignant lesions (HCC: 1.31 ± 0.28 and liver metastasis: 1.11 ± 0.22) and were significantly higher in benign lesions (hemangioma: 1.84 ± 0.37 and cyst: 2.61 ± 0.45) than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding hepatic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved. CONCLUSION: DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis.     

高场磁共振多b值弥散加权成像鉴别诊断肝血管瘤与肝细胞癌价值探讨

目的 探讨高场磁共振多b值弥散加权成像(DWI)鉴别诊断肝血管瘤(HH)与肝细胞癌(HCC)的价值。方法 2019年6月～2021年5月我院收治的85例肝脏局灶性占位性病变(FLL)患者,均接受高场MRI检查,记录不同b值下表观扩散系数(ADC)。均接受肝叶切除术,行组织病理学检查。绘制受试者工作特征(ROC)曲线,以曲线下面积(AUC)评估ADC的鉴别诊断价值。结果 在85例FLL患者中,术后组织病理学检查诊断为HH者28例(32.9%)、肝局灶性结节性增生(FNH)者18例(21.2%)和肝细胞癌(HCC)者39例(45.9%);在b值=50 s/mm²、b值=400 s/mm²和b值=1000 s/mm²时,HCC病灶ADC值分别为(2.41±0.20)×10^-3/mm²/s、(2.02±0.19)×10^-3/mm²/s和(1.73±0.15)×10^-3/mm²/s, FNH病灶分别为...     

Regional pulmonary response to a methacholine challenge using hyperpolarized 3He magnetic resonance imaging

Background and objective: Spirometry is insensitive to small airway abnormalities in asthma. Our objective was to evaluate regional lung structure and function using hyperpolarized ³He magnetic resonance imaging (MRI) before, during and after a methacholine challenge (MCh). Methods: Twenty‐five asthmatics (mean age = 34 ± 11 years) and eight healthy volunteers (HV) (mean age = 33 ± 11 years) underwent spirometry, plethysmography and hyperpolarized ³He MRI prior to a MCh. MRI was repeated following the MCh and again 25 min after salbutamol administration. ³He MRI gas distribution was quantified using semiautomated segmentation of the ventilation defect percent (VDP). Tissue microstructure was measured using the ³He apparent diffusion coefficient (ADC). Analysis of variance with repeated measures was used to evaluate changes at each time point as well as to determine interactions between regions of interest (ROI) and subject group. Pearson's correlations were performed to evaluate associations between ³He MRI measurements and established clinical measures. Results: In asthmatics, but not HV, whole‐lung ADC was increased post‐MCh (P < 0.01). In asthmatics only, ADC was increased post‐MCh in posterior ROI (P < 0.01) and all ROI in the superior‐inferior direction (P < 0.01). VDP was increased in posterior and inferior ROI (P < 0.001). There was a correlation between VDP and specific airway resistance (r = 0.74, P < 0.0001), dyspnoea score (r = 0.66, P < 0.01) and fractional exhaled nitric oxide (r = 0.45, P < 0.05). Conclusions: We evaluated the regional pulmonary response to methacholine and salbutamol using ³He MRI and showed heterogeneous VDP and ADC consistent with bronchoconstriction and gas trapping, respectively, post‐MCh. These regional alterations resolved post‐salbutamol.     

Magnetic resonance imaging in the detection of pancreatic neoplasms

Recently, with the rapid scanning time and improved image quality, outstanding advances in magnetic resonance (MR) methods have resulted in an increase in the use of MRI for patients with a variety of pancreatic neoplasms. MR multi-imaging protocol, which includes MR cross-sectional imaging, MR cholangiopancreatography and dynamic contrast-enhanced MR angiography, integrates the advantages of various special imaging techniques. The non-invasive all-in-one MR multi-imaging techniques may provide the comprehensive information needed for the preoperative diagnosis and evaluation of pancreatic neoplasms. Pancreatic neoplasms include primary tumors and pancreatic metastases. Primary tumors of the pancreas may be mainly classified as ductal adenocarcinomas, cystic tumors and islet cell tumors (ICT). Pancreatic adenocarcinomas can be diagnosed in a MRI study depending on direct evidence or both direct and indirect evidence. The combined MRI features of a focal pancreatic mass, pancreatic duct dilatation and parenchymal atrophy are highly suggestive of a ductal adenocarcinoma. Most cystic neoplasms of the pancreas are either microcystic adenomas or mucinous cystic neoplasms. Intraductal papillary mucinous tumors are the uncommon low-grade malignancy of the pancreatic duct. ICT are rare neoplasms arising from neuroendocrine cells in the pancreas or the periampullary region. ICT are classified as functioning and non-functioning. The most frequent tumors to metastasize to the pancreas are cancers of the breast, lung, kidney and melanoma. The majority of metastases present as large solitary masses with well-defined margins.