Mass-forming Focal Pancreatitis Research Articles

Role of Endoscopic Ultrasonography-Guided Fine Needle Aspiration/Biopsy in the Diagnosis of Autoimmune Pancreatitis

Type 1 autoimmune pancreatitis (AIP) is histologically characterized by lymphoplasmacytic sclerosing pancreatitis (LPSP). Recently, the diagnostic yield of endoscopic ultrasonography-guided fine needle aspiration/biopsy (EUS-FNA/B) for AIP has been reported. However, its role in the diagnostic flow of AIP is not fully elucidated. We retrospectively reviewed 53 consecutive patients who were suspected with AIP and underwent EUS-FNA/B. We evaluated the contribution of EUS-FNA/B to the diagnosis of AIP before considering response to steroid therapy among patients with diffuse enlargement of the pancreas and those with focal enlargement, respectively. Twenty-two patients showed diffuse pancreatic enlargement and 31 showed focal enlargement. The final diagnosis was definitive AIP in 32 patients, probable AIP in 2, possible AIP in 1, and mass-forming focal pancreatitis in 18. There was no change in diagnosis after EUS-FNA/B among patients with diffuse pancreatic enlargement, while diagnosis changed in 38.7% (12/31) among those with focal enlargement—there was a probable to definitive diagnosis in 4 patients, unspecified to definitive in 3, and unspecified to probable in 5. EUS-FNB provided a significantly higher sensitivity for typical pathological findings of LPSP than EUS-FNA, and 10 patients were diagnosed as pathologically definitive AIP by EUS-FNB, though none were by EUS-FNA (p = 0.002). EUS-FNA/B was useful in the diagnosis of focal type AIP, and steroid therapy could be introduced after the diagnosis was confirmed. Meanwhile, EUS-FNA/B provided no contribution to diagnosis of diffuse type AIP. EUS-FNB showed a higher diagnostic yield than FNA.

Differentiation of pancreatic carcinoma and mass-forming focal pancreatitis: qualitative and quantitative assessment by dynamic contrast-enhanced MRI combined with diffusion-weighted imaging.

Differentiation between pancreatic carcinoma (PC) and mass-forming focal pancreatitis (FP) is invariably difficult. For the differential diagnosis, we qualitatively and quantitatively assessed the value of dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in PC and FP in the present study. This study included 32 PC and 18 FP patients with histological confirmation who underwent DCE-MRI and DWI. The time-signal intensity curve (TIC) of PC and FP were classified into 5 types according to the time of reaching the peak, namely, type I, II, III, IV, and V, respectively, and two subtypes, namely, subtype-a (washout type) and subtype-b (plateau type) according to the part of the TIC profile after the peak. Moreover, the mean and relative apparent diffusion coefficient (ADC) value between PC and FP on DWI were compared. The type V TIC was only recognized in PC group (P < 0.01). Type IV b were more frequently observed in PC (P = 0.036), while type- IIa (P < 0.01), type- Ia (P = 0.037) in FP. We also found a significant difference in the mean and relative ADC value between PC and FP. The combined image set of DCE-MRI and DWI yielded an excellent sensitivity, specificity, and diagnostic accuracy (96.9%, 94.4%, and 96.0%). The TIC of DCE-MRI and ADC value of DWI for pancreatic mass were found to provide reliable information in differentiating PC from FP, and the combination of DCE-MRI and DWI can achieve a higher sensitivity, specificity, and diagnostic accuracy.

Quantified ADC histogram analysis: a new method for differentiating mass-forming focal pancreatitis from pancreatic cancer

As their prognosis and management are different, differentiation of mass-forming focal pancreatitis (FP) from pancreatic adenocarcinoma (PC) is important. However, the similar clinical presentations and imaging features of these conditions, along with inconclusive biopsy results can make such differentiation difficult. To determine whether apparent diffusion coefficient (ADC) histogram analysis can discriminate between a normal pancreas, FP, and PC. In a retrospective study, 25 PC patients, 14 FP patients, and 25 subjects with a normal pancreas underwent breath-hold diffusion-weighted imaging (DWI) on a 3.0 T magnetic resonance (MR) scanner. Regions of interest (ROIs) were drawn on the normal pancreases and on the entire focal lesions of both PC and FP. The ADC value was averaged from the lowest to 10th, 30th, 50th, and 100th percentile of the histogram (i.e. ADC10, ADC30, ADC50, and ADC100, respectively), and the results were analyzed statistically. There were no significant differences among the head, body, and tail of normal pancreases for any of the mean ADC values (P > 0.05). ADC10, ADC30, and ADC50 values demonstrated significant differences between lesion and non-lesion areas of both PC (P < 0.05) and FP (P < 0.05). Differences in lesion areas between PC and FP were found with ADC50 and ADC100 values (P < 0.05), and helped differentiate a normal pancreas from FP and PC, and FP from PC. Quantified ADC histogram can specifically reflect tissue heterogeneity and help differentiate a normal pancreas from FP and PC.

Can high-b-value diffusion weighted imaging differentiate between pancreatic cancer, mass forming focal pancreatitis and normal pancreas?

PurposeTo investigate whether high-b-value diffusion weighted imaging (DWI) and the apparent diffusion coefficient (ADC) values can differentiate pancreatic cancer (PC), mass forming focal pancreatitis (MFFP), and normal pancreas. Patients and methodsDiffusion weighted MR imaging (b=0 and 800s/mm2) was performed in 21 patients with histopathologically-proven pancreatic cancer, 19 patients with mass forming focal pancreatitis proven by histopathology and/or clinical follow up, and 21 normal control subjects. The signal intensity on DWI was visually evaluated and the ADC values of the pancreatic masses, the remaining pancreas, and the normal pancreas were measured and compared. ResultsOn high-b-value (800s/mm2) DW images, PC was slightly more hyperintense, relative to the remaining pancreas, than MFFP. The mean ADC value for PC (1.22±0.101×10−3mm2/s) was significantly lower than the remaining pancreas (1.99±0.206×10−3mm2/s; P<0.001), MFFP (1.53±0.122×10−3mm2/s; P<0.001), and the pancreatic gland in the control group (1.79±0.061×10−3mm2/s; P<0.001). There was also a significant difference between the mean ADC values of MFFP and the remaining pancreas (1.53±0.122 vs 1.89±0.169×10−3mm2/s; P<0.001). ConclusionDifferences on DWI and ADC measurements help to differentiate pancreatic cancer, mass forming focal pancreatitis, and normal pancreas.

Apparent diffusion coefficient measurements of the pancreas, pancreas carcinoma, and mass-forming focal pancreatitis

Mass-forming focal pancreatitis (FP) may mimic pancreatic cancer (PC) on magnetic resonance (MR) imaging, and the preoperative differential diagnosis is often difficult. Recently, the usefulness of diffusion-weighted imaging (DWI) in the diagnosis of pancreatic cancer has been reported in several studies. To investigate if apparent diffusion coefficient (ADC) measurements based on diffusion-weighted echo-planar imaging (DW-EPI) may distinguish between normal pancreas parenchyma, mass-forming focal pancreatitis, and pancreas carcinoma. MRI was performed on 64 patients: 24 with pancreas carcinoma (PC), 20 with mass-forming focal pancreatitis (FP), three patients with other focal pancreatic disease as well as 17 controls without any known pancreatic disease. Diffusion-weighted sequence with ADC maps and T2-weighted sequence for anatomical information was performed. Apparent diffusion coefficient (ADC) maps were automatically created and analyzed using a dedicated user interface. In the group with pancreas disease the abnormal parenchyma was detected by using T1- and T2-weighted images and the region of interest (ROI) was transferred exactly to the ADC map and the coefficients were registered. In the control group the ROI was set to the head of the pancreas followed by a similar registration of the ADCs. ADC values for mass-forming FP and PC differed significantly from ADC values for normal pancreas parenchyma (P = 0.001/P = 0.002). Mean ADC values for mass-forming FP were 0.69 ± 0.18 × 10(-3) mm(2)/s. ADC values for PC were 0.78 ± 0.11 × 10(-3) mm(2)/s, compared to ADC values of 0.17 ± 0.06 × 10(-3) mm(2)/s in the control group. However there was no significant difference in ADCs between PC and mass-forming FP (P = 0.15). ADC measurements clearly differentiated between normal pancreatic tissue and abnormal pancreas parenchyma (PC and mass-forming FP). However there is an overlap in values of PC and mass-forming FP, with the consequent problem of their correct identification.

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.

Pancreatic diffusion‐weighted imaging (DWI): Comparison between mass‐forming focal pancreatitis (FP), pancreatic cancer (PC), and normal pancreas

To compare diffusion-weighted imaging (DWI) findings and the apparent diffusion coefficient (ADC) values of pancreatic cancer (PC), mass-forming focal pancreatitis (FP), and the normal pancreas. DWI (b = 0 and 600 seconds/mm(2)) findings of 14 patients with mass-forming FP proven by histopathology and or clinical follow-up, 10 patients with histopathologically-proven PC, and 14 subjects with normal pancreatic exocrine function and normal imaging findings were retrospectively evaluated. ADC values of the masses, the remaining pancreas, and the normal pancreas were measured. On b = 600 seconds/mm(2) DWI, mass-forming FP was visually indistinguishable from the remaining pancreas whereas PC was hyperintense relative to the remaining pancreas. The mean ADC value of PC (1.46 +/- 0.18 mm(2)/second) was significantly lower than the remaining pancreas (2.11 +/- 0.32 x 10(-3) mm(2)/second; P < 0.0001), mass-forming FP (2.09 +/- 0.18 x 10(-3) mm(2)/second; P < 0.0001), and pancreatic gland in the control group (1.78 +/- 0.07 x 10(-3) mm(2)/second; P < 0.0005). There was no significant difference of ADC values between the mass-forming focal pancreatitis and the remaining pancreas (2.03 +/- 0.2 x 10(-3) mm(2)/second; P > 0.05). Differences on DWI may help to differentiate PC, mass-forming FP, and normal pancreas from each other.