Multidetector CT Dentascan evaluation of bone regeneration obtained with deproteinised bovine graft in residual cavity after mandibular cyst enucleation.

PURPOSE: This study compared spontaneous bone healing and regeneration obtained with deproteinised bovine graft in residual cavities after mandibular cyst enucleation using computed tomography (CT) Dentascan. MATERIALS AND METHODS: Eighty patients with a radiological diagnosis of mandibular cyst underwent surgical enucleation. Patients were divided into a control group (spontaneous healing, 40 patients) and a test group (deproteinised bovine graft, 40 patients). All patients underwent follow-up CT Dentascan 12 months after the procedure. For each residual cavity, apical-coronal and mesial-distal distance, average pixel intensity and volume were calculated and results compared between two groups using the t test. RESULTS: The control group showed mean volume, apical-coronal and mesial-distal distance of 703.2 ± 185.3 mm(3), 28.6 ± 9.4 mm and 25 ± 2.84 mm, respectively. In the test group, values were 738.2 ± 189.2 mm(3), 27.5 ± 3.6 mm and 25.3 ± 2.97 mm, respectively. There was no statistically significant difference between groups. Average pixel intensity was 1,102.8 ± 124.3 in the test group and 624.9 ± 133.3 in the control group, with a significant difference between groups (p<0.0001). CONCLUSIONS: The significantly higher average pixel intensity observed in the test group demonstrates the cavalue of treatment with biomaterials to obtain earlier bone regeneration.

Evaluation of the biliary and pancreatic system with 2D SSFSE, breathhold 3D FRFSE and respiratory-triggered 3D FRFSE sequences.

PURPOSE: The authors compared biliary and pancreatic imaging obtained through 2D single-shot fast spin-echo (SSFSE), breath-hold 3D fast recovery fast spin-echo (FRFSE) and respiratory-triggered 3D FRFSE sequences. MATERIALS AND METHODS: A total of 106 magnetic resonance cholangiopancreatography (MRCP) examinations performed between December 2007 and September 2008 were evaluated with a comparison of 2D SSFSE (thin section and thick slab), breath-hold 3D FRFSE and respiratory-triggered 3D FRFSE sequences. The biliary tract was divided into seven segments: right hepatic duct, left hepatic duct, common hepatic duct, cystic duct, common bile duct, cystic duct junction and biliary-pancreatic confluence. The main pancreatic duct was divided into three segments (head, body and tail). Visualisation of biliary variants was also compared. Two blinded radiologists evaluated segment visibility using a quantitative scale. The Student's t test for paired samples was used for statistical analysis. RESULTS: Compared with 2D SSFSE, respiratory-triggered 3D FRFSE sequences showed better visibility of the right hepatic duct (p=0.0277), the cystic duct (p=0.0081), the cystic duct junction (p=0.0010), the biliary-pancreatic confluence (p=0.0334) and biliary variants (p=0.0198). In the comparison between breath-hold 3D FRFSE and 2D SSFSE, a significant statistical difference was found in visualisation of the cystic duct (p=0.027), the cystic duct junction (p=0.020), the biliary-pancreatic confluence (p=0.0338) and biliary variants (p=0.0311). CONCLUSIONS: Three-dimensional FRFSE offers a significant benefit over conventional 2D imaging.

Magnetic resonance cholangiopancreatography and contrast-enhanced magnetic resonance cholangiopancreatography versus endoscopic ultrasonography in the diagnosis of extrahepatic biliary pathology.

PURPOSE: This study compared the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasonography (EUS) in evaluating the cause of extrahepatic bile duct dilatation. MATERIALS AND METHODS: Forty-five patients (26 men, mean age 57 years) with extrahepatic biliary dilatation, as shown by transabdominal ultrasound, with or without elevated biliary and pancreatic serum indices, were prospectively studied with MRCP and EUS between September 2007 and October 2008. EUS and MRCP were performed within no more than 24 h of each other to reduce the possibility of changes due to stone migration. Image analysis was carried out in a double-blind fashion. RESULTS: MRCP had 88.9% diagnostic accuracy, 91.9% sensitivity and 75% specificity, with 94.4% positive predictive value and 66.7% negative predictive value. EUS had 93.3% diagnostic accuracy, 97.3% sensitivity and 75% specificity; the positive and negative predictive values were 94.7% and 85.7%, respectively. CONCLUSIONS: MRCP and EUS do not show significant statistical differences in diagnostic accuracy. MRCP is an accurate, noninvasive modality in the study of extrahepatic biliary pathology. EUS is especially reliable in patients with extrahepatic biliary obstruction caused by endoluminal sludge.

Diffusion MRI for rectal cancer staging: ADC measurements before and after ultrasonographic gel lumen distension.

OBJECTIVES: To compare Apparent Diffusion Coefficient (ADC) measurements in rectal neoplastic lesions before and after lumen distension obtained with sonography transmission gel. METHODS: From January 2014 to July 2016, 25 patients (average age 63.7, range 41-85, 18 males) were studied for pre-treatment rectal cancer staging using a 1.5T MRI. Diffusion MRI was obtained using echo-planar imaging with b=800 value; all patients were studied acquiring diffusion sequences with and without rectal lumen distension obtained using sonography transmission gel. In both diffusion sequences, two blinded readers calculated border ADC values and small ADC values, drawing regions of interest respectively along tumour borders and far from tumour borders. Mean ADC values among readers - for each type of ADC measurement - were compared using Wilcoxon matched pairs signed rank test. Correlation was assessed using Pearson analysis. RESULTS: Border ADC mean value for diffusion MR sequences without endorectal contrast was 1.122mm2/sec, with 95% Confidence Interval (CI)=1.02-1.22; using gel lumen distension, higher border ADC mean value of 1.269mm2/s (95% CI=1.16-1.38) was obtained. Wilcoxon matched pairs signed rank test revealed statistical difference (p<0.01); a strong Pearson correlation was reported, with r value of 0.69. Small-ADC mean value was 1.038mm2/s (95% CI=0.91-1.16) for diffusion sequences acquired without endorectal distension and 1.127mm2/s (95% CI=0.98-1.27) for diffusion sequences obtained after endorectal gel lumen distension. Wilcoxon analysis did not show statistical difference (p=0.13). A very strong positive correlation was observed, with r value of 0.81. CONCLUSIONS: ADC measurements are slightly higher using endorectal sonographic transmission gel; ROI should be traced far from tumour borders, to minimize gel filled-pixel along the interface between lumen and lesion. Further studies are needed to investigate better reliability of ADC in rectal cancer MRI using sonographic gel intraluminal distension.

Cystic pancreatic neoplasms: diagnosis and management emphasizing their imaging features.

The incidence of cystic pancreatic neoplasms increased in the past decade, due to the recent advances in multidetector computed tomography and magnetic resonance imaging; several pancreatic cysts are incidentally encountered during diagnostic exams performed for non-pancreatic diseases. Indeed, cystic pancreatic tumors are currently considered relatively rare, accounting for approximately 10% of all pancreatic neoplasms. Serous cystadenoma, mucinous cystadenoma, intraductal papillary mucinous neoplasms and solid-pseudopapillary tumor represent about 90% of all pancreatic primary cystic tumours. The non-optimal diagnostic preoperative accuracy in distinguishing benign from malignant cystic lesions ensures that up till now there are no well-defined guidelines regarding the management of cystic pancreatic neoplasms. Imaging findings often do not allow the diagnosis, because there is a considerable overlap among the cystic lesions; the best pre-operative characterization is obtained by the association of all diagnostic procedures available. For their different histology and behavior, cystic pancreatic neoplasms need to be managed according to various factors. In this review, the main elements necessary for their management are assessed--radiological features, tumour dimensions, patients' characteristics, the mode of clinical presentation and the associated oncologic markers. A multidisciplinary approach--including gastroenterologists, radiologists and surgeons--should be adopted in order to perform a differential diagnosis and a correct management.

Magnetic resonance with diffusion-weighted imaging in the evaluation of transplanted kidneys: updating results in 35 patients.

BACKGROUND: We compared values of apparent diffusion coefficient (ADC) with renal function indices among a population of kidney transplant recipients who underwent magnetic resonance with diffusion-weighted imaging (DWI) of their grafts. MATERIALS AND METHODS: Thirty-five patients with right iliac transplanted kidneys were studied using 1.5-T magnetic resonance. Diffusion echo-planar sequences with several b-values were acquired to investigate transplanted grafts. Patients were divided into 3 groups according to their creatinine clearances; Group A, clearance >60 mL/min; Group B, clearance >30 and ≤60 mL/min; and Group C, clearance ≤30 mL/min. ADC values between groups were compared using Mann-Whitney U test. Receiver operating characteristic (ROC) curves were used to predict the normal function (Group A) versus renal failure cohorts (Group C). RESULTS: Comparing mean values of ADC between Group A and Group C patients, we observed a significant difference (P = .0003) with higher ADC values among patients with a normal creatinine clearance (>60 mL/min). Comparing Groups B and C did not show a significant difference (P = .05); nor did Group A and Group B reveal a significant difference (P = .38). To predict normal clearance values, the Group A ROC curve showed an area under curve (AUC) of 0.780 with a sensitivity of 92.3% and a specificity of 68.2% at a threshold ADC value of ≥2.08 × 10(-3) mm(2)/sec. In the prediction of low clearance values, the Group C ROC curve showed an AUC of 0.846 with a sensitivity of 83.3% and a specificity of 82.6% using a threshold ADC value of ≤2.07 × 10(-3) mm(2)/sec. CONCLUSIONS: Updating our experience among 35 patients, DWI was confirmed to be a promising noninvasive tool to assess renal function; an ADC ≥2.08 × 10(-3) mm(2)/sec may be used as a threshold to predict a normal clearance. However, an overlap of ADC values between groups is a limit.

Magnetic resonance with diffusion-weighted imaging in the evaluation of transplanted kidneys: preliminary findings.

BACKGROUND: The aim of this study was to compare values of apparent diffusion coefficient (ADC) and diffusion (D) with renal function indexes, in a population of kidney transplant recipients who underwent magnetic resonance with diffusion-weighted imaging (DWI) of the transplanted graft. MATERIALS AND METHODS: We studied 21 patients using a 1.5-Tesla magnetic resonance; DWI sequences were acquired with several b-values. Patients were divided into 3 groups by their creatinine clearance values: group A, clearance >60 mL/min; group B, clearance >30 and ≤60 mL/min; and group C, clearance ≤30 mL/min. ADCs values between groups were compared using the Mann-Whitney U test. Receiver operating characteristic (ROC) curves were created for prediction of normal renal function (group A) and renal failure (group C). RESULTS: Comparing mean values of ADC between groups A and C, we observed a difference (P=0.0012), with higher values in group A. Regarding mean values of D, we observed a difference between groups A and C (P=0.022). In the comparison between contiguous groups, we observed no difference for ADC and D values. In the prediction of normal clearance values (group A), ROC curve showed an area under curve (AUC) of 0.861, with a sensitivity of 88.89% and specificity of 75% using a threshold ADC value ≥2.1 × 10(-3) mm(2)/sec. For prediction of normal clearance values (group A), ROC curve showed an AUC of 0.787, with a sensitivity of 77.8% and specificity of 83.3% using a threshold D value ≥2.3 × 10(-3) mm(2)/sec. CONCLUSION: Although studies with a larger number of patients are needed, DWI represents a promising tool for noninvasive assessment of renal function. An ADC ≥ 2.1 × 10(-3) mm(2)/sec and a D ≥ 2.3 × 10(-3) mm(2)/sec may be used as a threshold for predicting normal clearance.