Pancreatic schwannoma: a rare differential diagnosis for a pancreatic mass.

Pancreatic schwannomas are rare benign tumors with low malignant potential and are often difficult to diagnose due to their non-specific presenting symptoms and overlapping radiological imaging characteristics. Cross-sectional imaging plays an important role in the initial diagnosis and in delineating the extent of the lesion. However, biopsy and histopathological examination remains the gold-standard for a definite diagnosis. The management of pancreatic schwannomas includes surgical resection often yielding excellent clinical outcomes with low recurrence rates. We present a case of a 33-year-old female patient with a history of a recurrent vague upper abdominal pain where CT of the upper abdomen showed a hypodense pancreatic mass. Robotic subtotal pancreatectomy was done with histopathology showing spindled Schwann cells indicative of a pancreatic schwannoma.

The value of 18F-FDG PET/MRI in prediction of microvascular invasion in hepatocellular carcinoma.

RATIONALE AND OBJECTIVES: Investigating the association between maximum standardized uptake value (SUVmax), peritumoral and intratumoral apparent diffusion coefficient (ADC) values and whether these parameters are useful in predicting the preoperative microvascular invasion (MVI) of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Forty-four patients [8 women and 36 men, median age of 62 (21-76)] with single HCCs (≥2 cm) who underwent preoperative 18F-FDG PET/MRI were retrospectively evaluated. The peritumoral and intratumoral ADC values were evaluated on diffusion-weighted images using Image J an open software and the intratumoral SUVmax values were measured on fusion 18F-FDG PET/MRI images. Univariate and multivariate logistic regression analyses were performed to determine the most influential factor predicting MVI. Interobserver agreement was checked using the intraclass correlation coefficient (ICC). RESULTS: Univariate analysis showed that the histologic grade, tumor size, maximum peritumoral ADC (PTband ADCmax), mean peritumoral ADC (PTband ADCmean), mean intratumoral ADC (IT ADCmean), and maximum SUV (SUVmax) correlated with MVI (p < 0.05). On multivariate analysis, the SUVmax was the only independent risk factor for the MVI of HCC [OR, 1.68; 95% CI (1.04-2.70); p = 0.032)]. An AUC value of 0.896, 95% CI, 0.786-1.0) had a sensitivity of 75% and specificity of 97% using the best cut-off SUVmax 5.85 to differentiate MVI-positive HCCs from MVI-negative. The PPV, NPV, and accuracy were 92.3%, 87%, and 89%, respectively. The ICC values were 0.95-0.99, a nearly perfect level of agreement. CONCLUSION: 18F-FDG PET/MRI is a useful noninvasive imaging tool for predicting the MVI of HCC.

Periampullary duodenal schwannoma mimicking ampullary neoplasm.

Schwannomas are neurogenic tumors that arise from Schwann cells in the neural sheath. Gastrointestinal schwannomas occur most often in the stomach, followed by the colon and the rectum. Duodenal schwannomas are rare amongst mesenchymal tumors of the gastrointestinal tract and only a few cases have been reported up to the current date with an incidence of approximately 2%-6%. Duodenal Schwannomas do not have characteristic imaging features thereby cannot be easily differentiated from other submucosal and adjacent extraluminal neoplasms. We present a case of a 76-year old male patient that presented to our hospital with abdominal pain and was diagnosed after an upper gastrointestinal endoscopy with an ampullary duodenal neoplasm that proved to be a periampullary duodenal Schwannoma on histopathology. Duodenal Schwannomas although rare should be considered in the differential diagnosis of ampullary neoplasms.

A case of peribiliary hepatic cysts in a cirrhotic liver: A mimicker of Klatskin Tumor.

Patients with end-stage liver disease may present to healthcare facilities with features of obstructive jaundice and a picture of hilar cholangiocarcinoma on radiological imaging. Careful observation and knowledge of the presence and higher prevalence of peribiliary hepatic cysts in a cirrhotic liver can aid in differentiating this benign entity from malignancy that may halt or delay the patients' eligibility for receiving a liver transplant. We present a case of a patient with liver cirrhosis initially diagnosed as Klatskin tumor on imaging then as a simple case of multiple peribiliary hepatic cysts with the patient eventually undergoing successful liver transplantation.

Intravoxel Incoherent Motion of Colon Cancer Liver Metastases for the Assessment of Response to Antiangiogenic Treatment: Results from a Pilot Study.

OBJECTIVE: This study was aimed at evaluating the intravoxel incoherent motion (IVIM) parameter alterations of liver metastases of colorectal carcinoma (CRC) during antiangiogenic bevacizumab combination therapy. METHODS: Twenty-five patients with CRC liver metastases treated with bevacizumab in combination with FOLFOX-or-FOLFIRI protocols were enrolled in the study. MRI was performed using a 1.5-tesla scanner pre-treatment (PT) and at 3, 6, and 9 months of therapy. Routine abdominal MRI sequences and an IVIM-DWI (diffusion-weighted imaging) sequence were obtained. The IVIM-DWI sequence was executed with 16 b-values varying from 0 to 1,400 s/mm2. The mean values of apparent diffusion coefficient (ADC), true diffusion (D), pseudodiffusion (D*), and perfusion fraction (f) of each metastasis were obtained for all b-values, and the time-related changes were recorded to analyze the chronologic responses to antiangiogenic therapy. The RECIST 1.1 criteria were used for the evaluation of treatment response. RESULTS: The diameters of the metastases diminished significantly at 9 months when compared with PT (p = 0.03). The D (p = 0.10) and ADC (p = 0.21) values of the metastases increased at 9 months of therapy. D* was the highest at 3 months (p =0.24); it decreased at 6 (p =0.97) and 9 months (p =0.87) of therapy. The f value had peaked at 3 months (p =0.51) and started to decrease thereafter. At 6 months, f decreased to the lowest values (p =0.12). CONCLUSION: IVIM parameters, particularly the perfusion fraction, may quantitatively reflect the response to antiangiogenic treatment. The antiangiogenic response manifests after 3 months of therapy before the RECIST-related response.

Diagnostic performances of intravoxel incoherent motion and conventional diffusion-weighted imaging in the differential diagnosis of benign and malignant portal vein thrombus.

PURPOSE: To evaluate the diagnostic accuracy of intravoxel incoherent motion (IVIM) and diffusion-weighted imaging (DWI) parameters in the differential diagnosis of portal vein thrombus (PVT). METHODOLOGY: Thirty-five patients with PVT were enrolled in this retrospective study. Precontrast axial in-phase and out-of-phase T1-weighted (W) turbo field echo (TFE), axial and coronal T2-W single-shot turbo spin echo, IVIM with b values between 0 and 1300 s/mm2 and conventional DWI with b factors of 50, 400, and 800 s/mm2 with single-shot echo-planar imaging, and postcontrast dynamic T1-W volumetric interpolated breath-hold examination images obtained with 1.5 T MR unit were evaluated. For quantitative analysis of conventional DWI, an ADC map was reconstructed from conventional DWI using all b values. For quantitative evaluation of IVIM, the SI was calculated from each b value. A specific software program was applied to calculate D (true diffusion coefficient), D* (pseudodiffusion coefficient associated with blood flow), and f (perfusion fraction). The differentiation between benign and malignant PVT was based on the criteria outlined in the study by Catalano et al. (Radiology 254:154-162, 2010). RESULTS: The ADC values of the malignant PVT were significantly lower than those of benign PVTs (p = 0.005). Malignant PVTs had a tendency to show higher f values in comparison with benign PVTs without statistical significance (p = 0.750). The best discriminative parameter was ADC values, which demonstrated a sensitivity of 80.0% and a specificity of 72.7% with cut-off value of 1.00 × 10-3 mm2/s. CONCLUSION: ADC values might be more superior tool than IVIM parameters in differentiation between malignant and benign PVT.

The efficacy and utilisation of preoperative multiparametric magnetic resonance imaging in robot-assisted radical prostatectomy: does it change the surgical dissection plan?

OBJECTIVE: We investigated the effect of the use of multiparametric prostate magnetic resonance imaging (mp-MRI) on the dissection plan of the neurovascular bundle and the oncological results of our patients who underwent robot-assisted radical prostatectomy. MATERIAL AND METHODS: We prospectively evaluated 60 consecutive patients, including 30 patients who had (Group 1), and 30 patients who had not (Group 2) mp-MRI before robot-assisted radical prostatectomy. Based on the findings of mp-MRI, the dissection plan was changed as intrafascial, interfascial, and extrafascial in the mp-MRI group. Two groups were compared in terms of age, prostate-specific antigen (PSA), Gleason sum scores and surgical margin positivity. RESULTS: There was no statistically significant difference between the two groups in terms of age, PSA, biopsy Gleason score, final pathological Gleason score and surgical margin positivity. mp-MRI changed the initial surgical plan in 18 of 30 patients (60%) in Group 1. In seventeen of these patients (56%) surgical plan was changed from non-nerve sparing to interfascial nerve sparing plan. In one patient dissection plan was changed to non-nerve sparing technique which had extraprostatic extension on final pathology. Surgical margin positivity was similar in Groups 1, and 2 (16% and 13%, respectively) although, Group 1 had higher number of high- risk patients. mp-MRI confirmed the primary tumour localisation in the final pathology in 27 of of 30 patients (90%). CONCLUSION: Preoperative mp-MRI effected the decision to perform a nerve-sparing technique in 56% of the patients in our study; moreover, changing the dissection plan from non-nerve-sparing technique to a nerve sparing technique did not increase the rate of surgical margin positivity.

Primary renal angiosarcoma with progressive clinical course despite surgical and adjuvant treatment: A case report.

Angiosarcoma is an extremely rare, high-grade malignancy, which accounts for <2% of all soft-tissue sarcomas. Cases of primary renal angiosarcoma represent 1% of these. Angiosarcomas involving the kidney usually originate from metastatic skin lesions or primary visceral lesions and most often occur in the sixth and seventh decades of life. The present study describes a case of primary renal angiosarcoma that presented as a large right-sided renal mass with symptoms of flank pain. Despite surgical removal of the tumor, recurrent disease with associated lung metastases was identified at the surgical site following adjuvant chemotherapy. The patient succumbed to the disease 13 months after the diagnosis.

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.

Review of magnetic resonance spectroscopy in the liver and the pancreas.

Proton magnetic resonance spectroscopy is a powerful tool for in vivo biochemical characterization of normal and abnormal tissues. The initial application in the abdomen was the measurement of fat concentration in the liver using chemical shift imaging. The success of chemical shift imaging in providing a semiquantitative measure of liver fat concentration led to the application of the more quantitative single-voxel volume-selective spectroscopy of the liver. This single-voxel volume-selective spectroscopic technique is able to characterize the different lipids and metabolites present in the liver and the pancreas, providing information about the ratio of unsaturated and saturated lipids. The purposes of this article were to review the spectroscopic techniques and to discuss some of the clinical applications of these techniques in the abdomen.

Magnetic resonance measurement of diffusion in the abdomen.

Diffusion-weighted (DW) magnetic resonance imaging is an emerging noninvasive technique increasing its spectrum of use in the abdomen. Diffusion-weighted imaging has been used as add-on to routine abdominal protocol because it may potentially substitute contrast-enhanced imaging in cases under risk of nephrogenic systemic fibrosis. The apparent diffusion coefficient (ADC) images calculated from DW images enable qualitative and quantitative evaluations of tissue water mobility and functional environment because of changes in intracellular, extracellular, and intravascular tissue compartments. This article presents the basic physics of the ADC measurement, the techniques for performing ADC measurements of the liver and the pancreas, and the clinical applications of DW imaging.

Magnetic resonance imaging of adenocarcinoma of the pancreas.

Magnetic resonance imaging (MRI) is a valuable tool in the assessment of the full spectrum of pancreatic disease. A standard MR protocol including noncontrast T1-weighted fat-suppressed and dynamic gadolinium-enhanced gradient-echo imagings is sensitive for the evaluation of pancreatic cancer. Optimal use of MRI in the investigation of pancreatic cancer occurs in the following circumstances: (1) detection of small non-contour-deforming tumors, (2) evaluation of local extension and vascular encasement, (3) determination of the presence of lymph node and peritoneal metastases, and (4) determination and characterization of associated liver lesions and liver metastases. The objective of this study was to describe the attribute of MRI for evaluating pancreatic cancer.

Magnetic resonance imaging in pancreatitis.

Pancreatitis can occur in acute and chronic forms. Magnetic resonance imaging (MRI) plays an important role in the early diagnosis of both conditions and complications that may arise from acute or chronic inflammation of the gland. Standard MRI techniques including T1-weighted and T2-weighted fat-suppressed imaging sequences together with contrast-enhanced imaging can both aid in the diagnosis of acute pancreatitis and demonstrate complications as pseudocysts, hemorrhage, and necrosis. Combined use of MRI and MR cholangiopancreatography can show both parenchymal findings that are associated with chronic pancreatitis including pancreatic size and signal and arterial enhancements, all of which are diminished in chronic pancreatitis. The degree of main pancreatic duct dilatation and/or the number of side branch ectasia determines the diagnosis of chronic pancreatitis and its severity. In this paper, we report the spectrum of imaging findings of acute and chronic pancreatitis on MRI and MR cholangiopancreatography.

Imaging of the pancreas with secretin enhancement.

Magnetic resonance cholangiopancreatography is a noninvasive imaging technique for evaluation of the pancreatic duct and the biliary tree. Secretin is a polypeptide hormone that has numerous physiological effects, including stimulation of the pancreatic secretion of bicarbonate-rich fluid and transient increase in the tone in the sphincter of Oddi. As a result, secretin administration usually results in distention of the pancreatic duct; therefore, visualization of the pancreatic ductal anatomy is often substantially improved. Awareness of its value by referring clinicians and radiologists will increase its use in the future.

Magnetic resonance imaging of gallbladder and biliary system.

Gallbladder and biliary system pathologic component is a spectrum of benign and malignant conditions. Standard magnetic resonance imaging techniques when used together with magnetic resonance cholangiopancreatography (MRCP) can evaluate gallbladder and biliary system pathologic conditions. Inflammatory diseases are characterized by thickening and intense mucosal contrast enhancement of the affected bile ducts and or gallbladder wall. Postinflammatory changes can be appreciated on MRCP with short or long segment strictures of the bile ducts. Serial contrast-enhanced images show reactive inflammatory changes in the liver parenchyma. Neoplastic diseases of the gallbladder and the biliary tree are evaluated on T2-weighted fat-suppressed echo train and serial contrast-enhanced images and their obstructive effect can be displayed on MRCP images. In this paper, we will review the spectrum of MRI findings of gallbladder and biliary system pathologic conditions.

Diffusion-weighted magnetic resonance imaging of the pancreas.

Diffusion-weighted imaging (DWI) assesses the random motion of the water protons. The technique is more frequently used in body imaging, and recent investigations showed its use in pancreatic imaging. Diffusion-weighted imaging can be helpful as a complementary imaging method in the differentiation between mass-forming focal pancreatitis and pancreatic adenocarcinoma. The apparent diffusion coefficient (ADC) values derived from DWI can distinguish between simple pancreatic cyst, inflammatory cysts, and cystic neoplasms of the pancreas. Presence of parenchymal fibrosis in chronic pancreatitis causes diffusion restriction and results in lower ADC values on baseline DWI. The ADC values reveal either delayed peak after secretin stimulation or lower peak values in patients with early chronic pancreatitis, which may be helpful to depict chronic pancreatitis in its earliest stage. In this paper, we reviewed the technical aspects of DWI and its use in pancreatic imaging.

Magnetic resonance imaging in pancreas transplantation.

Magnetic resonance imaging (MRI) plays an important role in the evaluation of pancreas transplantation. Standard MRI, magnetic resonance angiography, and MR cholangiopancreatography can demonstrate the changes of the anatomy after transplantation. Vascular complications are assessed by MR angiography. Magnetic resonance cholangiopancreatography reveals ductal changes resulting from acute and/or chronic rejection and determines leaks with the use of a secretin-stimulated MR cholangiopancreatography. Serial contrast-enhanced MRI may detect the diminished perfusion that is related to the graft rejection or vascular complications. In this paper, we reviewed types of pancreas transplantation procedures, complications that arise in a short and/or a long term after the transplantation, and their assessment by MRI.

MRI and MRCP findings of the pancreas in patients with diabetes mellitus: compared analysis with pancreatic exocrine function determined by fecal elastase 1.

GOALS: To review magnetic resonance imaging and magnetic resonance cholangiopancreatography (MRCP) findings in patients with diabetes mellitus (DM), with pancreatic exocrine insufficiency, and with combined pancreatic exocrine insufficiency and DM. STUDY: MRI/MRCP findings of 82 consecutive patients with DM (n=28), pancreatic exocrine insufficiency (n=25), and combination of both (n=29) were evaluated and compared with MRI/MRCP findings of 21 healthy volunteers with normal pancreatic exocrine function. Pancreatic exocrine function was determined by fecal elastase 1. MRCP images were evaluated according to the Cambridge classification. MRI of the pancreas was assessed for pancreatic size, signal intensity ratio (SIR), and arterial/venous enhancement ratio (A/V). RESULTS: On MRI, significant difference was present in terms of mean values of pancreatic size (P<0.0001), A/V (P<0.02), and SIR (P<0.005) between the control group and groups of patients with DM, pancreatic exocrine insufficiency, and combined DM and pancreatic exocrine insufficiency. No significant difference was observed between groups of patients with DM and pancreatic exocrine function alone in terms of pancreatic size, A/V, and SIR. Chronic pancreatitis MRCP findings were present with increasing frequency in groups of DM, pancreatic exocrine insufficiency, and combination of both. CONCLUSIONS: MRI/MRCP findings suggesting chronic pancreatitis may exist in patients with DM comparable to patients with pancreatic exocrine insufficiency. The frequency and severity of MRI/MRCP findings increase when the patients have combined DM and pancreatic exocrine insufficiency.