Autoimmune pancreatitis in the context of IgG4-related disease: Review of imaging findings

Current understanding of autoimmune pancreatitis (AIP) recognizes a histopathological subtype of the disease to fall within the spectrum of IgG4-related disease. Along with clinical, laboratory, and histopathological data, imaging plays an important role in the diagnosis and management of AIP, and more broadly, within the spectrum of IgG4-related disease. In addition to the defined role of imaging in consensus diagnostic protocols, an array of imaging modalities can provide complementary data to address specific clinical concerns. These include contrast-enhanced computed tomography (CT) and magnetic resonance (MR) imaging for pancreatic parenchymal lesion localization and characterization, endoscopic retrograde and magnetic resonance cholangiopancreatography (ERCP and MRCP) to assess for duct involvement, and more recently, positron emission tomography (PET) imaging to assess for extra-pancreatic sites of involvement. While the imaging appearance of AIP varies widely, certain imaging features are more likely to represent AIP than alternate diagnoses, such as pancreatic cancer. While nonspecific, imaging findings which favor a diagnosis of AIP rather than pancreatic cancer include: delayed enhancement of affected pancreas, mild dilatation of the main pancreatic duct over a long segment, the “capsule” and “penetrating duct” signs, and responsiveness to corticosteroid therapy. Systemic, extra-pancreatic sites of involvement are also often seen in AIP and IgG4-related disease, and typically respond to corticosteroid therapy. Imaging by CT, MR, and PET also play a role in the diagnosis and monitoring after treatment of involved sites.     

Magnetic resonance imaging of pancreatitis: An update

Magnetic resonance (MR) imaging plays an important role in the diagnosis and staging of acute and chronic pancreatitis and may represent the best imaging technique in the setting of pancreatitis due to its unmatched soft tissue contrast resolution as well as non-ionizing nature and higher safety profile of intravascular contrast media, making it particularly valuable in radiosensitive populations such as pregnant patients, and patients with recurrent pancreatitis requiring multiple follow-up examinations. Additional advantages include the ability to detect early forms of chronic pancreatitis and to better differentiate adenocarcinoma from focal chronic pancreatitis. This review addresses new trends in clinical pancreatic MR imaging emphasizing its role in imaging all types of acute and chronic pancreatitis, pancreatitis complications and other important differential diagnoses that mimic pancreatitis.     

肺气肿的无创影像学测量进展

肺气肿为呼吸系统常见病,是一种以终末细支气管远端气腔永久性扩大,伴肺泡壁破坏及肺弹性收缩功能障碍为特点的进行性损坏性疾病。因而早期诊断对于肺气肿的治疗及预后均有着极其重要的意义,本文将从影像学角度分别以X线胸片、胸部CT及核磁共振成像三方面对比研究肺气肿的影像学表现及诊断。     

Staging of severity and prognosis of acute pancreatitis by computed tomography and magnetic resonance imaging—A comparative study

BACKGROUND: Determination of severity of acute pancreatitis is important to determine prognosis. AIMS: (1) the staging of acute pancreatitis by computed tomography and magnetic resonance imaging, (2) the correlation of computed tomography and magnetic resonance severity indices and 3) the correlation of magnetic resonance severity index with C-reactive protein, Ranson score, duration of hospitalization and clinical outcome. PATIENTS: Thirty-five patients (median age: 64 (27-89)) were studied. Twenty-two patients had biliary acute pancreatitis. METHODS: The following examinations were conducted: (1) computed tomography 48 h, 7 and 30 days after admission, (2) magnetic resonance imaging 7 and 30 days after admission, (3) C-reactive protein and 4) Ranson score. Clinical outcome was determined on a scale 0-3 (0: remission, 1: local complications, 2: systemic complications, 3: death). RESULTS: Six of 35 patients (17%) had necrotizing acute pancreatitis. Fifteen of 35 patients (43%) had severe acute pancreatitis according to Ranson criteria. A significant correlation was noted between magnetic resonance severity index and C-reactive protein (r=0.419, p<0.005), Ranson score (r=0.431, p<0.05), duration of hospitalization (r=0.497, p<0.01) and clinical outcome (r=0.420, p<0.05). Comparison of the imaging methods showed a significant correlation between magnetic resonance severity index and computed tomography severity index (r=0.887, p<0.01). CONCLUSION: Magnetic resonance imaging is of comparable diagnostic and prognostic value with computed tomography in the staging of acute pancreatitis.     

Focal autoimmune pancreatitis: Radiological characteristics help to distinguish from pancreatic cancer

AIM: To identify the radiological characteristics of focal autoimmune pancreatitis (f-AIP) useful for differentiation from pancreatic cancer (PC). METHODS: Magnetic resonance imaging (MRI) and triple-phase computed tomography (CT) scans of 79 patients (19 with f-AIP, 30 with PC, and 30 with a normal pancreas) were evaluated retrospectively. A radiologist measured the CT attenuation of the pancreatic parenchyma, the f-AIP and PC lesions in triple phases. The mean CT attenuation values of the f-AIP lesions were compared with those of PC, and the mean CT attenuation values of pancreatic parenchyma in the three groups were compared. The diagnostic performance of CT attenuation changes from arterial phase to hepatic phase in the differentiation between f-AIP and PC was evaluated using receiver operating characteristic (ROC) curve analysis. We also investigated the incidence of previously reported radiological findings for differentiation between f-AIP and PC. RESULTS: The mean CT attenuation values of f-AIP lesions in enhanced phases were significantly higher than those of PC (arterial phase: 60 ± 7 vs 48 ± 10, P < 0.05; pancreatic phase: 85 ± 6 vs 63 ± 15, P < 0.05; hepatic phase: 95 ± 7 vs 63 ± 13, P < 0.05). The mean CT attenuation values of f-AIP lesions were significantly lower those of uninvolved pancreas and normal pancreas in the arterial and pancreatic phase of CT (P < 0.001, P < 0.001), with no significant difference at the hepatic phase or unenhanced scanning (P = 0.4, P = 0.1). When the attenuation value increase was equal or more than 28 HU this was considered diagnostic for f-AIP, and a sensitivity of 87.5%, specificity of 100% and an area under the ROC curve of 0.974 (95%CI: 0.928-1.021) were achieved. Five findings were more frequently observed in f-AIP patients: (1) sausageshaped enlargement; (2) delayed homogeneous enhancement; (3) hypoattenuating capsule-like rim; (4) irregular narrowing of the main pancreatic duct (MPD) and/or stricture of the common bile duct (CBD); and (5) M     

Multifocal autoimmune pancreatitis: A retrospective study in a single tertiary center of 26 patients with a 20-year literature review

BACKGROUNDMultifocal-type autoimmune pancreatitis (AIP), sometimes forming multiple pancreatic masses, is frequently misdiagnosed as pancreatic malignancy in routine clinical practice. It is critical to know the imaging features of multifocal-type AIP to prevent misdiagnosis and unnecessary surgery. To the best of our knowledge, there have been no studies evaluating the value of diffusionweighted imaging (DWI), axial fat-suppressed T1 weighted image (T1WI), and dynamic contrast enhanced-computed tomography (DCE-CT) in detecting the lesions of multifocal-type AIP.AIMTo clarify the exact prevalence and radiological findings of multifocal AIP in our cohorts and compare the sensitivity of DWI, axial fat-suppressed T1WI, and DCE-CT for detecting AIP lesions. We also compared radiological features between multifocal AIP and pancreatic ductal adenocarcinoma with several key imaging landmarks.METHODSTwenty-six patients with proven multifocal AIP were retrospectively included. Two blinded independent radiologists rated their confidence level in detecting the lesions on a 5-point scale and assessed the diagnostic performance of DWI, axial fat-suppressed T1WI, and DCE-CT. CT and magnetic resonance imaging of multifocal AIP were systematically reviewed for typical imaging findings and compared with the key imaging features of pancreatic ductal adenocarcinoma.RESULTSAmong 118 patients with AIP, 26 (22.0%) had multiple lesions (56 lesions). Ulcerative colitis was associated with multifocal AIP in 7.7% (2/26) of patients, and Crohn’s disease was present in 15.3% (4/26) of patients. In multifocal AIP, multiple lesions, delayed homogeneous enhancement, multifocal strictures of the main pancreatic duct, capsule-like rim, lower apparent diffusion coefficient values, and elevated serum Ig4 level were observed significantly more frequently than pancreatic ductal adenocarcinoma, whereas the presence of capsule-like rim in multifocal-type AIP was lower in frequency than total AIP. Of these lesions of multifocal AIP, DWI detected 89.3% (50/56) and 82.1% (46/56) by the senior and junior radiologist, respectively.CONCLUSIONMultifocal AIP is not as rare as previously thought and was seen in 22.0% of our patients. The diagnostic performance of DWI for detecting multifocal AIP was best followed by axial fat-suppressed T1WI and DCE-CT.     

Autoimmune pancreatitis： Functional and morphological recovery after steroid therapy

Autoimmune pancreatitis, a recently recognized type of chronic pancreatitis, is not rare in Japan, but reports of it elsewhere are relatively uncommon. We report the first preoperatively diagnosed case of autoimmune pancreatitis in Hungary, which responded well to steroid treatment and provided radiographic and functional evidence of this improvement. A 62-year-old female presented with a 4-month history of recurrent epigastric pain and a 5-kg weight loss. The oral glucose tolerance test (OGTT) indicated diabetes mellitus and the result of the fecal elastase test was abnormal. Ultrasonography (US) and the CT scan demonstrated a diffusely enlarged pancreas, and endoscopic retrograde cholangiopancrea-tography (ERCP) an irregular main pancreatic duct with long strictures in the head and tail. Autoimmune pancreatitis was diagnosed. The patient was started on 32 mg prednisolone daily. After 4 wk, the OGTT and faecal elastase test results had normalized. The repeated US and CT scan revealed a marked improvement of the diffuse pancreatic swelling, while on repeated ERCP, the main pancreatic duct narrowing was seen to be ameliorated. It is important to be aware of this disease and its diagnosis, because AIP can clinically resemble pancreatobiliary malignancies, or chronic or acute pancreatitis. However, in contrast with chronic pancreatitis, its symptoms and morphologic and laboratory alterations are completely reversed by oral steroid therapy.     

Mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm: A case report

Mass forming chronic pancreatitis is very rare. Diagnosis could be done by the pathologic findings of focal inflammatory fibrosis without evidence of tumor in pancreas. A 34-year-old man presented with right upper abdominal pain for a few weeks and slightly elevated bilirubin level on clinical findings. Radiological findings of multidetector-row computed tomography, magnetic resonance(MR) imaging with MR cholangiopancreatography and endoscopic ultrasonography revealed focal branch pancreatic duct dilatation with surrounding delayed enhancing solid component at uncinate process and head of pancreas, suggesting branch duct type intraductal papillary mucinous neoplasm. Surgery was done and pathology revealed the focal chronic inflammation, fibrosis, and branch duct dilatation. Herein, I would like to report the first case report of mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm.     

Autoimmune pancreatitis： A review

Autoimmune pancreatitis has emerged over the last 40 years from a proposed concept to a well established and recognized entity. As an efficient mimicker of pancreatic carcinoma, its early and appropriate recognition are crucial. With mounting understanding of its pathogenesis and natural history, significant advances have been made in the diagnosis of autoimmune pancreatitis. The characteristic laboratory features and imaging seen in autoimmune pancreatitis are reviewed along with some of the proposed diagnostic criteria and treatment algorithms.     

自身免疫性胰腺炎与小胰腺癌的CT、MRCP征象分析

目的 分析自身免疫性胰腺炎(AIP)与小胰腺癌的CT、MRCP影像学征象的差异,提高对AIP的认识及诊断的准确率.方法 回顾性分析符合2008年AIP亚洲诊断标准的24例AIP及病理证实的25例小胰腺癌(≤2 cm)的影像学资料,从胰腺的形态改变、密度及强化方式、胰管及胰周、胰外表现等方面进行比较,采用×2检验或确切概率法行统计学处理.结果 在AIP和小胰腺癌组间,肿块部位、远端胰腺萎缩、肿块持续强化、胰管“截断征”、“鞘膜征”及肾脏受累征象差异具有统计学意义(x2 =9.010、10.506、15.288、8.688、6.292和4.966,P＜0.05),但是只有远端胰腺萎缩和肿块持续强化征象在局限性AIP与小胰腺癌组间差异具有统计学意义(P＜0.05).结论 弥漫性AIP的影像学改变具有特异性,与小胰腺癌容易鉴别诊断,但局灶性AIP与小胰腺癌鉴别诊断价值有限.     

Strategy to differentiate autoimmune pancreatitis from pancreas cancer

Autoimmune pancreatitis (AIP) is a newly described entity of pancreatitis in which the pathogenesis appears to involve autoimmune mechanisms. Based on histological and immunohistochemical examinations of various organs of AIP patients, AIP appears to be a pancreatic lesion reflecting a systemic "IgG4-related sclerosing disease". Clinically, AIP patients and patients with pancreatic cancer share many features, such as preponderance of elderly males, frequent initial symptom of painless jaundice, development of new-onset diabetes mellitus, and elevated levels of serum tumor markers. It is of uppermost importance not to misdiagnose AIP as pancreatic cancer. Since there is currently no diagnostic serological marker for AIP, and approach to the pancreas for histological examination is generally difficult, AIP is diagnosed using a combination of clinical, serological, morphological, and histopathological features. Findings suggesting AIP rather than pancreatic cancer include: fluctuating obstructive jaundice; elevated serum IgG4 levels; diffuse enlargement of the pancreas; delayed enhancement of the enlarged pancreas and presence of a capsule-like rim on dynamic computed tomography; low apparent diffusion coefficient values on diffusion-weighted magnetic resonance image; irregular narrowing of the main pancreatic duct on endoscopic retrograde cholangiopancreatography; less upstream dilatation of the main pancreatic duct on magnetic resonance cholangiopancreatography, presence of other organ involvement such as bilateral salivary gland swelling, retroperitoneal fibrosis and hilar or intrahepatic sclerosing cholangitis; negative work-up for malignancy including endoscopic ultrasound-guided fine needle aspiration; and steroid responsiveness. Since AIP responds dramatically to steroid therapy, accurate diagnosis of AIP can avoid unnecessary laparotomy or pancreatic resection.     

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.     

Utility of pancreatography for diagnosing autoimmune pancreatitis

AIM: To identify pancreatographic findings that facilitate differentiating between autoimmune pancreatitis (AIP) and pancreatic cancer (PC) on endoscopic retrograde cholangiopancreatography (ERCP) and magnetic resonance cholangiopancreatography (MRCP). METHODS: ERCP findings of 48 AIP and 143 PC patients were compared. Diagnostic accuracies for AIP by ERCP and MRCP were compared in 30 AIP patients. RESULTS: The following ERCP findings suggested a diagnosis of AIP rather than PC. Obstruction of the main panc...     

Study on chronic pancreatitis and pancreatic cancer using MRS and pancreatic juice samples

AIM:To investigate the markers of pancreatic diseases and provide basic data and experimental methods for the diagnosis of pancreatic diseases.METHODS:There were 15 patients in the present study,among whom 10 had pancreatic cancer and 5,chronic pancreatitis.In all patients,pancreatic cancer or chronic pancreatitis was located on the head of the p-a-ncrea-s.Pa-thology da-ta-of a-ll p-a-tients wa-s confirmed by biopsy and surgery.Among the 10 patients with pancreatic cancer,3 people had a medical history of l...     

Radiological diagnosis of duodenocaval fistula:A case report and literature review

Duodenocaval fistula(DCF) is an uncommon but lethal clinical entity.The high mortality has been attributed to the difficulty of diagnosis before attempts at definitive therapy.In this case report,we describe a patient with a series of computed tomography(CT) examinations over a 2-mo period in hospital.A low-density air bubble appeared in the inferior vena cava(IVC) on the second day in hospital and became clear on day 19,and gradually enlarged.Magnetic resonance imaging(MRI) also clearly demonstrated a high...     

Acute pancreatitis successfully diagnosed by difffusion-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.     

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.