Advanced Imaging of Chronic Pancreatitis

Chronic pancreatitis is characterized by continuing inflammation, destruction, and irreversible morphological changes in the pancreatic parenchyma and ductal anatomy. These changes lead to chronic pain and/or loss of function. Although these definitions are simple, the clinical diagnosis of chronic pancreatitis remains difficult to make, especially for early disease. Routine imaging modalities such as transabdominal ultrasound and standard CT scans are insensitive for depicting early disease, and detect only advanced chronic pancreatitis. Advances in imaging modalities including CT, MRI with gadolinium contrast enhancement, MRI with magnetic resonance cholangiopancreatography (MRI/MRCP), MRI/MRCP with secretin-stimulation (S-MRCP), endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS) allow earlier diagnosis of chronic pancreatitis. This article reviews the recognized findings, advantages, and disadvantages of the various imaging modalities in the management of chronic pancreatitis, specifically CT, MRI with or without MRCP and/or S-MRCP, ERCP, and EUS.     

MR多参数成像评估慢性胰腺炎临床分级的价值

目的 探讨应用多种MRI技术评估慢性胰腺炎(CP)临床分级的价值.方法 纳入经病理和临床随访证实的65例CP患者,按M-annheim分级分为轻度组(14例)、中度组(37例)和进展组(14例),并以20例健康志愿者作为对照.在上腹部常规T1WI及T2WI抑脂扫描后,进行胰腺MRCP检查及胰腺动态MR检查.测量T1WI、T2WI加权扫描的胰腺实质信号及肝脏信号,获取它们的比值(rT1、rT2),根据MRCP测量主胰管最大直径(MPD),并对胰腺病变进行评估、分类;测量动态MR增强时胰腺实质信号值,并计算强化率;ROC分析MRI表现与CP临床分级的相关性.结果 正常、轻度、中度和进展组rT1分别为0.98±0.27、0.84±0.12、0.81±0.16和0.75±0.24,中度、进展组较正常组明显降低(P<0.01);rT2分别为1.28±0.30、1.46±0.44、1.46±0.55和1.76±0.72,各组间无统计学差异;MPD为(2.0±0.6)mm、(5.4±2.4)mm、(6.5±3.3)mm和(8.1±4.1)mm,各组间差异显著(P值均<0.01).轻度、中度和进展组的剑桥重度分级分别有4例(29%)、33例(90%)和13例(93%),差异显著(P<0.01);胰管结石分别有2例(14%)、11例(30%)和5例(36%),胰腺假性囊肿分别有0例、6例(16%)和3例(21%),胰腺萎缩分别有4例(29%)、22例(60%)和10例(71%),各组间均无统计学差异.正常、轻度、中度和进展组的胰腺动态增强扫描实质期与动脉期胰腺信号强化率比值(P/A)分别为0.88±0.08、1.10±0.08、1.37±0.15和1.48±0.53,各组间差异显著(P<0.05).rT1值、剑桥分级、胰管直径及P/A比值与临床分级均有相关性(r值分别为0.34、0.41、0.62、-0.43).ROC分析显示,MPD>2.5 mm、rT1<0.8、P/A>0.8诊断CP均有较好的敏感性和特异性,三者结合时诊断CP的特异性可提高到95%.结论 应用磁共振的T1WI、MRCP及动态增强检查能准确、良好地评估CP的严重程度,其中MRCP的敏感性及特异性最高,其次是动态增强检查与T1平扫.     

Guidelines for the Diagnostic Cross Sectional Imaging and Severity Scoring of Chronic Pancreatitis

The paper presents the international guidelines for imaging evaluation of chronic pancreatitis. The following consensus was obtained: Computed tomography (CT) is often the most appropriate initial imaging modality for evaluation of patients with suspected chronic pancreatitis (CP) depicting most changes in pancreatic morphology. CT is also indicated to exclude other potential intraabdominal pathologies presenting with symptoms similar to CP. However, CT cannot exclude a diagnosis of CP nor can it be used to exclusively diagnose early or mild disease. Here magnetic resonance imaging (MRI) and MR cholangiopancreatography (MRCP) is superior and is indicated especially in patients where no specific pathological changes are seen on CT. Secretin-stimulated MRCP is more accurate than standard MRCP in the depiction of subtle ductal changes. It should be performed after a negative MRCP, when there is still clinical suspicion of CP. Endoscopic ultrasound (EUS) can also be used to diagnose parenchymal and ductal changes mainly during the early stage of the disease.No validated radiological severity scoring systems for CP are available, although a modified Cambridge Classification has been used for MRCP. There is an unmet need for development of a new and validated radiological CP severity scoring system based on imaging criteria including glandular volume loss, ductal changes, parenchymal calcifications and parenchymal fibrosis based on CT and/or MRI. Secretin-stimulated MRCP in addition, can provide assessment of exocrine function and ductal compliance. An algorithm is presented, where these imaging parameters can be incorporated together with clinical findings in the classification and severity grading of CP.     

慢性胰腺炎的猫模型制作及磁共振影像表现

目的 制备猫慢性胰腺炎(CP)模型,观察其MRI与MRCP的影像学表现.方法 32只猫按数字表法随机分为对照组及制模后3、5、7周组.采用胰管不全结扎法制备CP模型,术后3、5、7周行MRI平扫及MRCP检查,观察胰腺形态,测量胰管直径及感兴趣区(ROI)的T1信号强度值(Tls),计算同层胰腺及肝脏Tls比值.结果 制模的24只猫中存活19只,其中15只形成CP,病理证实轻、中、重度CP分别为7、5、3只,制模成功率为62.5％.在MRI上,猫的正常胰腺显示清晰,T1加权像信号强度高于肝脏,T2加权像信号强度低于肝脏;在MRCP图像上,4只正常猫显示主胰管,胰管最大径(0.79±0.18)mm,并可见胰管及胆总管共同开口于十二指肠降部.正常胰腺及轻、中、重度CP感兴趣区的rTls值分别为1.03±0.06、0.95±0.08、0.90±0.10、0.80±0.11,各CP组与正常对照组间差异均有统计学意义(t=2.18,P＜0.05;t =2.89,P＜0.05;t =4.63,P＜0.01);胰管最大径分别为(0.79±0.18)、(0.95±0.24)、(1.26±0.31)、(2.67±0.71)mm,中、重度CP组与正常对照组间差异均有统计学意义(P＜0.05或＜0.01).结论 胰管不全结扎可制备猫的CP模型.猫的胰腺解剖形态、CP的MRI及MRCP表现与人类相似.     

MRCP and MRI findings in 9 patients with autoimmune pancreatitis

AIM: To evaluate magnetic resonance cholangiopancre-atography (MRCP) findings in conjunction with magnetic resonance (MR) images in autoimmune pancreatitis (AIP) patients. METHODS: Nine patients with AIP underwent MRI, MRCP, endoscopic retrograde cholangiopancreatography (ERCP), computed tomography, and ultrasonography. The MRCP and MR images taken before and after steroid therapy were reviewed and compared with other imaging modalities. The MRCP findings of the AIP cases were compared to those of 10 cases with carcinoma of the head of the pancreas. RESULTS: On MRCP, the narrowed portion of the main pancreatic duct noted on ERCP was not visualized, while the non-involved segments of the main pancreatic duct were visualized. The degree of upstream dilatation of the proximal main pancreatic duct was milder than that seen in cases of pancreatic carcinoma. Stenosis or obstruction of the lower bile duct was detected in 8 patients. MR images showed enlargement of the pancreas with decreased signal intensity on T1-weighted MR images, increased signal intensity on T2-weighted MR images, and, in 3 patients, a hypointense capsule-like rim. After steroid therapy, the previously not visualized portion of the main pancreatic duct was seen, along with improvement of the bile duct stenosis. Pancreatic enlargement decreased, and the abnormal signal intensity on both T1- and T2-weighted MR images became isointense. CONCLUSION: MRCP cannot differentiate irregular narrowing of the main pancreatic duct seen with AIP from stenosis of the main pancreatic duct seen with pancreatic carcinoma. However, MRCP findings in conjunction with MR imaging of pancreatic enlargement that shows abnormal signal intensity on T1- and T2-weighted MR images are useful in supporting a diagnosis of AIP.     

Morphological and functional recovery following acute and acute recurrent pancreatitis in children: A prospective sequential 2-point evaluation

BackgroundThe functional and morphological recovery following an episode of acute pancreatitis (AP) in children still remains ill understood as research exploring this is limited. We aimed to characterize the morphological and functional changes in pancreas following AP and ARP (acute recurrent pancreatitis) in children.MethodsChildren with AP were followed prospectively and assessed at two time points at least 3 months apart, with the first assessment at least 3 months after the AP episode. Exocrine and endocrine functions were measured using fecal elastase and fasting blood sugar/HbA1c levels respectively. Morphological assessment was done using endoscopic ultrasound (EUS) and magnetic resonance imaging and cholangiopancreatography (MRI/MRCP).ResultsSeventy-three children (boys:59%; mean age:8.4 ± 3.2years) were studied and 21 of them (29%) progressed to ARP. Altered glucose homeostasis was seen in 19 (26%) at first and 16 (22%) at second assessment and it was significantly more in ARP group than the AP group at first (42.8%vs19.2%; p = 0.03) as well as second assessment (38.1%vs15.3%; p = 0.03). Twenty-one children (28.7%) at first and 24 (32.8%) at second assessment developed biochemical exocrine pancreatic insufficiency. EUS detected indeterminate and suggestive changes of chronic pancreatitis in 21% at first (n = 38) and 27.6% at second assessment (n = 58). On MRCP, main pancreatic duct and side branch dilatation were seen in 15 (20.5%) and 2 (2.7%) children respectively.ConclusionsMore than one-quarter of children have evidence of altered glucose homeostasis and biochemical exocrine pancreatic insufficiency following an episode of AP. Similarly, morphological features of chronicity seen in some of the children suggest that a fraction of subjects may develop chronic pancreatitis on longer follow-up.     

内镜超声和经内镜逆行胰胆管造影在慢性胰腺炎诊断中的价值

目的 评价EUS和ERCP对慢性胰腺炎(CP)的诊断灵敏度和特异度,探讨在CP诊断中EUS和ERCP的价值.方法 采用多中心联合调查方法,回顾分析1994年5月至2004年5月全国22个分研究中心的确诊的CP病例,以组织学诊断为"金标准",采用接受者工作曲线(receiver operating characteristic,ROC)分析EUS和ERCP的诊断灵敏度和特异度.结果 共人选CP患者1994例,男1298例,女696例.年龄5～85(48.9 ±15.0)岁.所有CP患者中,有组织学诊断239例(11.98%);胰腺外分泌功能试验(BT-PABA)261例(13.09%),腹部平片416例(20.86%),腹部B超1424例(71.41%),CT 889例(44.58%),MRI和MRCP245例(12.29%),ERCP628例(31.49%),EUS258例(12.94%).各诊断方法的诊断灵敏度和特异度分别为EUS(88%和93%)、ERCP(87%和93%)、MRI和MRCP(66%和85%)、CT(61%和85%)、B超(69%和82%)、腹部平片(32%和80%)、BT-PABA(83%和80%).结论 在CP诊断方法中,EUS和ERCP对CP且具有较高的灵敏度和特异度,EUS较ERCP灵敏度和特异度更高.     

Recent advances and novel methods in pancreatic imaging

Traditional imaging studies for evaluating pancreatic disease including abdominal ultrasound (US) and computerized tomography (CT) are widely utilized due to their availability, non-invasiveness, and familiarity to practitioners. The addition of endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography (MRCP) has contributed significantly to the clinician's the ability to safely sample tissue, stage malignancy, evaluate the pancreatic ductal anatomy, and look for subtle parenchymal changes in the setting of chronic pancreatitis. The role of endoscopic retrograde cholangiopancreatography (ERCP) has diminished with the use of these less invasive modalities. Limitations in these conventional techniques include a lack of sensitivity and specificity in diagnosing early chronic pancreatitis, difficulties in differentiating malignancy from chronic or focal pancreatitis, and accuracy of staging pancreatic malignancy, particularly with regard to vascular involvement. Several recent advances in traditional imaging techniques have been described, which may improve our ability to accurately diagnose and stage pancreatic disease. Advances have been made in the standard modalities for imaging the pancreas such as multidetector CT, micro-bubble contrast enhanced ultrasound, and secretin stimulated MRCP. Other novel methods of pancreatic imaging have recently been described including EUS elastography, optical coherence tomography, diffusion weighted MRI, and MR spectroscopy. This article will review the recent advances in both traditional pancreatic imaging modalities as well as some of the emerging technologies for imaging evaluating diseases of the pancreas. As experience and clinical evidence accumulate, the role of these imaging techniques will continue to evolve.     

Imaging diagnosis of pancreatic cancer:A state-of-the-art review

Pancreatic cancer(PC)remains one of the deadliest cancers worldwide,and has a poor,five-year survival rate of 5%.Although complete surgical resection is the only curative therapy for pancreatic cancer,less than20%of newly-diagnosed patients undergo surgical resection with a curative intent.Due to the lack of early symptoms and the tendency of pancreatic adenocarcinoma to invade adjacent structures or to metastasize at an early stage,many patients with pancreatic cancer already have advanced disease at the time of their diagnosis and,therefore,there is a high mortality rate.To improve the patient survival rate,early detection of PC is critical.The diagnosis of PC relies on computed tomography(CT)and/or magnetic resonance imaging(MRI)with magnetic resonance cholangiopancreatography(MRCP),or biopsy or fine-needle aspiration using endoscopic ultrasound(EUS).Although multi-detector row computed tomography currently has a major role in the evaluation of PC,MRI with MRCP facilitates better detection of tumors at an early stage by allowing a comprehensive analysis of the morphological changes of the pancreas parenchyma and pancreatic duct.The diagnosis could be improved using positron emission tomography techniques in special conditions in which CT and EUS are not completely diagnostic.It is essential for clinicians to understand the advantages and disadvantages of the various pancreatic imaging modalities in order to be able to make optimal treatment and management decisions.Our study investigates the current role and innovative techniques of pancreatic imaging focused on the detection of pancreatic cancer.     

Quantification of pancreatic exocrine function of chronic pancreatitis with secretin-enhanced MRCP

AIM:To obtain reference values for pancreatic flow output rate(PFR)and peak time(PT)in healthy volunteers and chronic pancreatitis(CP);to correlate quantification of secretin enhanced magnetic resonance cholangiopancreatography(SMRCP)of pancreatic fluid output following secretin with fecal elastase-1(FE-1)tests.METHODS:The present study includes 53 subjects comprised of 17 healthy individuals and 36 patients with CP from April 2011 to January 2013.The 36 patients with CP were divided into three groups of mild CP(n=14),moderate CP(n=19)and advanced CP(n=3)by M-ANNHEIM classification for CP..Fifty-three cases underwent FE-1 test and magnetic resonance imaging using 3.0 T-device(Signa EXCITE,GE Healthcare).Coronal T2-weighted single-shot turbo spin-echo,spiratory triggered,covering the papillae,duodenum and small bowel.MRCP was performed with a heavily T2-weighted fat-suppressed long TE HASTE sequence (thick slab 2D MRCP sequence),repeated every 2 min up to 11 min after 0.1 mL/kg secretin injection(Secrelux,Sanochemia,Germany).FE-1 test used sandwich enzyme-linked immunosorbent assay(ELISA)test(ScheBo.Tech,Germany).RESULTS:A good linear correlation showed between the calculated volume and the actual volume by Phantom experiments.Fifty-three paired Quantification of secretin enhanced magnetic resonance cholangiopancreatography(MRCPQ)and FE-1 data sets were analyzed.The mean FE-1 of 53 cases was 525.41±94.44μg/g for 17 healthy volunteers,464.95±136.13μg/g for mild CP,301.55±181.55μg/g for moderate CP,229.30±146.60μg/g for advanced CP.Also,there was statistically significant difference in FE-1(P=0.0001)between health and CP.The mean values of PFR and PT were 8.18±1.11 mL/min,5.76±1.71 min for normal;7.27±2.04 mL/min,7.71±2.55 min for mild CP;4.98±2.57 mL/min,9.10±3.00 min for moderate CP;4.13±1.83 mL/min,12.33±1.55 min for advanced CP.Further,statistically significant difference in PFR(P=0.0001)and PT(P=0.0001)was observed between health and CP.Besides,there was correlation(r=0.79)and consistency(K=0.6     

慢性胰腺炎研究进展

慢性胰腺炎以胰腺慢性纤维化、钙化、胰管慢性炎症和胰管结石为主要病理改变,其发病率在国内外有逐年升高的趋势.虽然内镜治疗技术的飞速发展、胰酶替代药物的广泛应用、影像学和实验室技术的发展使慢性胰腺炎的内科诊断和治疗措施有了较大的进展。但确切的病因和发病机制尚不清楚,其诊断和治疗也尚未达成共识.因此,迫切需要开展慢性胰腺炎的流行病学、病因学、诊断学和治疗学等相关基础与,临床研究,为慢性胰腺炎的诊治提供理论和实践依据,并尽快制定出科学、客观的慢性胰腺炎诊治规范,指导其诊断和治疗.     

Magnetic Resonance Cholangiopancreatography Reports in the Evaluation of Chronic Pancreatitis: A Need for Quality Improvement

Background: Numerous publications from academic centers suggest that magnetic resonance cholangiopancreatography (MRCP) can diagnose early chronic pancreatitis (CP) and assess pancreatic secretory reserve/function. However, the rigorous composite interpretation methods and quantitative secretory dynamics reported in these studies are not routinely measured in clinical practice.Therefore, the utility of routine MRCP reports in the clinical setting is unknown. Study Design: Cross-sectional study of patients referred to a tertiary center who underwent both MRCP and endoscopic pancreas function testing (ePFT) for assessment of chronic pancreatitis and abdominal pain. Aims: To compare MRCP and sMRCP reports to a reference standard pancreas function test for diagnosis of chronic pancreatitis. Methods: Source population: patients seen within a pancreas clinic at a tertiary referral center. MRCP and sMRCP reports were reviewed to record pancreas duct (dilation, side-branch changes), parenchyma enhancement (T₁, T₂ signal) and physiologic response (duodenal filling, pancreas duct response) to secretin. ePFT was categorized based on previously published data (normal peak bicarbonate >80 mEq/l). Referent values were calculated for MRCP and sMRCP using secretin ePFT as gold standard. Results: A total of 69 patients were identified (mean age 43.5 ± 12; 65.2% female). 28 (40.6%) patients had abnormal ePFT based on their peak bicarbonate level. The mean bicarbonate values in the abnormal PFT and normal PFT groups were 59 ± 13.9 and 95.3 ±12.6 mEq/l, respectively. Peak bicarbonate decreased with severity of chronic pancreatitis on MRCP (p = 0.0016). There was fair agreement of MRCP and ePFT (κ 0.335 [0.113,0.557]). The pre-stimulation pancreas duct changes reported were found to be the only predictor of abnormal pancreas function (p = 0.002). The post-stimulation findings of duodenal filling (p = 0.47), T₂ enhancement (p = 0.21) or change in pancreas duct caliber (p = 0.3) reported did not improve MRCP agreement with ePFT. Overall diagnostic accuracy, sensitivity and specificity were 70, 85 and 46%, respectively, for MRCP reports using ePFT as the gold standard. Conclusions: Pancreas ductal features described on routine MRCP reports correlate with abnormal pancreas function. Current MRCP reports should be standardized to include all radiologie information available in hopes of predicting early chronic pancreatitis.     

Pancreatic duct changes are not associated with early signs of chronic pancreatitis at magnetic resonance imaging (MRI) in patients with primary sclerosing cholangitis

Abstract

Objective. The association between chronic pancreatitis (CP) and primary sclerosing cholangitis (PSC) has been reported previously. The aims of the present study were to evaluate the presence of early pancreatic abnormalities and duct changes, using MRCP/MRI in PSC and to evaluate possible risk factors for these changes and their clinical importance. Materials and methods. One hundred and three patients with PSC were identified among all MRI liver/pancreas referrals in 2001–2005. MRCP was used to grade pancreatic duct changes in three groups: grade 0 (normal), grade 1 (mild) and grade 2 (severe). For detection of early MRI signs of CP, the pancreas-spleen signal intensity ratio (SIR), the arterial and early venous phase ratio (A/PV ratio) and the age-related size of the pancreas were evaluated. Results. Pancreatic duct changes were found in 24% of the PSC patients. The pancreatic duct changes were associated with extrahepatic biliary involvement and long duration of PSC but not associated with pancreas-spleen SIR, A/PV ratio, pancreas size, previous post-ERCP or acute pancreatitis. Severe pancreatic duct changes were significantly associated to abdominal pain. Clinically significant CP was seen in one PSC patient (1%). Conclusions. Pancreatic duct changes are associated with extrahepatic bile duct strictures and not with the early MRI signs of CP. Therefore, pancreatic duct changes seem to be part of the spectrum of PSC and should not be defined as CP. Pancreatic duct changes are of limited clinical importance but may contribute to abdominal pain in PSC.     

Evaluation of pancreatic exocrine function by secretin-enhanced magnetic resonance cholangiopancreatography

AIM: To assess the feasibility and usefulness of secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) for evaluation of pancreatic exocrine function. METHODOLOGY: S-MRCP was performed in 20 patients with mild (n = 8) or severe (n = 12) chronic pancreatitis (according to the grade of exocrine pancreatic insufficiency indicated by the Lundh test) and in 10 volunteers without pancreatic disease. MRCP images were evaluated before and 10 minutes after the intravenous administration of 0.5 IU/kg secretin. The changes in pancreatic tissue T2 signal intensity and duodenal filling after the injection of secretin were determined by means of S-MRCP. The S-MRCP findings were then compared with those of the Lundh test. RESULTS: The pancreatic T2 signal intensity showed a significant elevation after secretin administration in the volunteers and in the patients with mild or severe chronic pancreatitis. This elevation was significantly lower in patients with mild and severe chronic pancreatitis than in the volunteers (66.85+/-15.77 and 24.45+/-5.85 vs. 200.0+/-45.07, respectively). After administration of secretin. the diameter of the duodenum was significantly increased in all three groups. This duodenal filling was significantly reduced in patients with mild or severe exocrine pancreatic insufficiency as compared with the volunteers (4.12+/-1.33 and 1.70+/-0.77 vs. 15.38+/-1.73, respectively). There was no significant difference in pancreatic T2 signal intensity changes or in duodenal filling in patients with mild or severe exocrine pancreatic insufficiency. There were significant correlations between the pancreatic T2 signal intensity changes and the duodenal filling and the results of the Lundh test (r = -0.616 and -0.78). CONCLUSION: These results demonstrate that the administration of secretin increases the T2 signal intensity of the pancreatic tissue and the diameter of the duodenum to different extents in normal subjects and in patients with chronic pancreatitis. This suggests that S-MRCP can provide information of value in the assessment of an exocrine pancreatic insufficiency.     

Technology insight: applications of MRI for the evaluation of benign disease of the pancreas

This article reviews the role of MRI in the evaluation of benign pancreatic disease. Although MRI and magnetic resonance cholangiopancreatography (MRCP) are most often used to evaluate the liver and bile duct, technical advances such as the use of secretin stimulation also allow for high-quality imaging of the pancreas and pancreatic ductal system. Secretin-stimulated MRCP (S-MRCP) can aid the diagnosis of acute and chronic pancreatitis, and delineate ductal pathology such as benign strictures and duct leaks. There seems to be a role for S-MRCP in the assessment of pancreatic function and (possibly) sphincter of Oddi dysfunction. When endoscopic or surgical therapy is planned, S-MRCP can help to establish a diagnosis as well as offer a 'road map' to guide therapy. S-MRCP is noninvasive and almost entirely without risk to the patient, which gives it a distinct advantage over traditional endoscopic methods of diagnosis for conditions such as pancreas divisum and other ductal pathology. The information provided by S-MRCP, obtained before endoscopic or surgical therapy is attempted, can assist the patient and physician in making a fully informed decision with regard to the risks and probable benefits of any planned intervention.     

Magnetic resonance imaging of experimental mouse colitis and association with inflammatory activity

BACKGROUND: Ulcerative colitis and Crohn's disease are the major chronic inflammatory bowel diseases affecting the gastrointestinal tract in humans. Imaging techniques such as endoscopy and computed tomography are used to monitor disease activity. Magnetic resonance imaging (MRI) is emerging as a diagnostic modality, and studies have shown that MRI can be used in the diagnostic procedure of patients with inflammatory bowel disease. The aim of the present study was to investigate the role of MRI in quantitatively reflecting inflammation in an experimental mouse colitis model. METHODS: Colonic inflammation was induced by exposing mice to dextran sulfate sodium. MRI was used to assess colon wall thickness, T2-weighted (T2w) signal, and contrast-enhanced T1-weighted (T1w) signal in inflamed and healthy animals in vivo. Haptoglobin and interleukin-1beta served as systemic and local inflammatory markers, and macroscopic ex vivo scoring of the colon was performed to assess colonic inflammation. RESULTS: Dextran sulfate sodium-exposed animals displayed increased levels of inflammatory markers and higher inflammatory score compared with healthy animals. Colon wall thickness and contrast-enhanced T1w signal were significantly increased in dextran sulfate sodium-exposed compared with healthy animals. In addition, the T2w signal was positively correlated with haptoglobin levels and colon wall thickness in the inflamed animals. CONCLUSIONS: Our results show that MRI can be used to depict healthy and inflamed mouse colon and that the T2w signal, contrast-enhanced T1w signal, and colon wall thickness may be used to characterize inflammation in experimental colitis. These potential biomarkers may be useful in the evaluation of putative drugs in longitudinal studies in both mice and humans.     

Imaging of skeletal muscle

Various diagnostic imaging techniques such as sonography, computed tomography, scintigraphy, radiography, and magnetic resonance imaging (MRI) have made possible the noninvasive evaluation of skeletal muscle injury and disease. Although these different modalities have roles to play, MRI is especially sensitive in the diagnosis of muscle disorders and injury and has proved to be useful in determining the extent of disease, in directing interventions, and in monitoring the response to therapies. This article describes how magnetic resonance images are formed and how the signal intensities in T1- and T2-weighted images may be used for diagnosis of the above-mentioned conditions and injuries.     

Magnetic resonance imaging in diagnosis, staging and radiotherapy planning for prostate cancer

T2-weighted magnetic resonance imaging (MRI), preferably using an endorectal coil, is able to clearly depict the normal prostatic anatomy and to identify prostate cancer with fair diagnostic accuracy. The latter can be further increased by using functional techniques such as spectroscopy (assessment of prostatic metabolism), dynamic contrast-enhanced MRI (assessment of angiogenesis) and diffusion-weighted imaging (assessment of cellular density). T2-weighted MRI is an important tool for local staging of prostate cancer in patients clinically staged as cT1 or cT2, because of its high specificity for macroscopic capsular extension or seminal vesicle invasion. Compared to CT-imaging, MRI depicts the internal prostatic anatomy, prostatic margins and the extent of prostatic tumours much more clearly. This benefit can be exploited to improve the accuracy of target delineations in radiotherapy planning.     

Evaluating the role of imaging methods in the diagnosis of chronic pancreatitis

OBJECTIVE: To evaluate the role of imaging methods in the diagnosis of chronic pancreatitis (CP) in improving the accuracy of a clinical diagnosis of CP. METHODS: The results of the imaging methods used for 129 cases diagnosed as CP in Peking Union Medical College Hospital from 1991 to 2000 were retrospectively analyzed. The imaging methods included ultrasonography (US), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasonography (EUS). RESULTS: The sensitivity of EUS and MRCP was high and was in good agreement with ERCP in the diagnosis of CP. The sensitivity of ERCP was superior to US and CT (P < 0.05). The sensitivity of US and CT for diagnosing dilation of the pancreatic duct was 59.4% and 60%, respectively, the specificity was 93.8% and 95.7%, respectively. BT‐PABA had a better correlation with ERCP in the group with severe changes of the pancreatic duct than in the mild or moderate group. The more complications of CP that were present, the more severe the lesions of the pancreatic duct. CONCLUSION: Among the traditional imaging modalities for diagnosing CP, ERCP is the most sensitive. MRCP and EUS, the promising and novel examination techniques, have high sensitivity and good agreement with ERCP.     

Hepatocellular carcinoma--a comparative study of MR imaging and angiography

We used magnetic resonance imaging (MRI) at 0.2 T and angiography to evaluate hepatocellular carcinoma (HCC) in 43 patients who had not received therapy. Tumor detection rate by MRI was 84%, T2-weighted spin echo imaging being the best detection method, though one case could only be detected by T1-weighted imaging (Inversion Recovery method). The signal intensity of the tumor relative to the surrounding liver parenchyma was studied using MRI, and tumor staining using angiography. Where there was a high signal intensity in the T2-weighted spin echo images there was a corresponding tendency for tumor staining to be marked. MRI demonstrated the inner structure--which resembles random high-intensity threads on a lower-intensity background--of hypervascular tumors. Tumors with capsules appeared with the capsule clearly delineated irrespective of the signal intensity of the tumor itself.