1,721,001 research outputs found
Biliary complications following orthotopic liver transplantation: May contrast-enhanced MR Cholangiography provide additional information?
No full textPURPOSE:
To assess whether contrast-enhanced T1-weighted MR Cholangiography may provide additional information in the evaluation of biliary complications in orthotopic liver transplant recipients.
MATERIAL AND METHODS:
Eighty liver transplant patients with suspicion of biliary adverse events underwent MR imaging at 1.5 T scanner. After acquisition of axial T1-/T2-weighted images and conventional T2-weighted MR Cholangiography (image set 1), 3D gradient-echo T1-weighted fat-suppressed LAVA (Liver Acquisition with Volume Acceleration) sequences were obtained about 30 min after intravenous infusion of mangafodipir trisodium (Mn-DPDP,Teslascan(®)) (image set 2). The diagnostic value of mangafodipir trisodium-enhanced MR Cholangiography in the detection of biliary complications was tested by separate analysis results of image set 1 alone and image set 1 and 2 together. MRI results were correlated with direct cholangiography in 46 patients, surgery in 14 and/or clinical-radiological follow-up in the remaining 20 cases.
RESULTS:
The level of confidence in the assessment of biliary adverse events was significantly increased by the administration of mangafodipir trisodium (p < 0.05). Particularly, contrast-enhanced T1-weighted LAVA sequences tended to out-perform conventional T2-weighted MR Cholangiography in the delineation of anastomotic and non-anastomotic biliary strictures and in the diagnosis of biliary leak.
CONCLUSIONS:
Contrast-enhanced T1-weighted MR Cholangiography may improve the level of diagnostic confidence provided by conventional T2-weighted MR Cholangiography in the evaluation of biliary complications after orthotopic liver transplantation
Choledocolithiasis: Diagnostic accuracy of MR cholangiopancreatography. Three-year experience
No full textThe purpose of this study was to evaluate the diagnostic accuracy of MR cholangiopancreatography (MRCP) in the detection of common bile duct stones. A series of 286 consecutive patients were referred for MRCP, that was performed with a 1.5 T MR unit, through a non-breath-hold, respiratory-triggered, fat-suppressed, two-dimensional, heavily T2-weighted fast spin-echo sequence in the coronal plane. Axial T1 and T2-weighted sequences were first obtained. Axial, coronal, and Maximum Intensity Projection images were evaluated by three independent readers, who were asked to determine whether stones were present or not inside the biliary tract. The findings of MRCP images were compared with endoscopic retrograde cholangiopancreatography, percutaneous trans-hepatic cholangiography, intra-operative cholangiography, surgical, or imaging follow-up findings. Two-hundred and seventy-eight out of 286 MRCP examinations were judged diagnostic by the three reviewers. Among the 278 patients included in our study group, biliary tract lithiasis was proved in 76 cases (27%). On the basis of reviewers' reading, MRCP had sensitivity 92-93%, specificity 97-98%, positive predictive value 91-93%, negative predictive value 97-98%, and the diagnostic accuracy ranged between 95% and 96% in the detection of calculi. Interobserver agreement was excellent (K = 0.84, kappa statistic). MRCP showed a high diagnostic accuracy and an excellent inter-observer agreement in the detection of common bile duct stones
VALUTAZIONE DELLA FUNZIONE ESOCRINA DEL PANCREAS TRAPIANTATO CON ESAME RM DOPO STIMOLO SECRETINICO
No full textMR virtual endoscopy of the urinary tract
No full textAbstract
OBJECTIVE. We investigated the feasibility of applying surface-rendered virtual endoscopy to the visualization of the upper urinary tract by processing unenhanced MR urography data sets. SUBJECTS AND METHODS. Twenty-six patients, having neoplastic lesions (n = 9), calculi (n = 8), pelviureteric junction stenoses (n = 4), postoperative fibrotic strictures (n = 3), and extrinsic compressions of the ureter (n = 2), underwent unenhanced MR urography. Virtual endoscopy of the upper urinary tract was obtained using a thresholding technique and surface-rendering MR urography data sets. RESULTS. Virtual endoscopy of the renal pelvis and calices was feasible in all cases on the side of the urinary obstruction. Virtual endoscopy of the ureter was obtained for a diameter of at least larger than 5 mm. The nondilated side could be partially explored in 11 cases (43%). The mean virtual endoscopy threshold required for the visualization of the urinary tract was 157.36-159.94. The mean time for virtual endoscopy was 13.8 min. Endoluminal masses were found in three (12%) of 26 cases on the renal pelvis (corresponding to neoplastic lesions), and occlusions, in 23 (88%) of 26 on the pelviureteric junction and ureter (neoplastic lesions and other abnormalities). CONCLUSION. Virtual endoscopy of MR urography data sets is feasible in patients with urinary tract dilatation. Virtual endoscopy displays the renal pelvis, calices, and ureter and, moreover, can show endoluminal changes caused by abnormalities
MR IMAGING (MRI) OF BREAST PROSTETHIC IMPLANTS: USEFULNESS OF FAST SE IR (FSEIR) SEQUENCE
No full textBILIARY COMPLICATIONS IN ORTHOTOPIC LIVER TRANSPLANTATION: EVALUATION WITH MR-CHOLANGIOPANCREATOGRAPHY (MRCP)
No full textMR cholangiography in orthotopic liver transplantation: sensitivity and specificity in detecting biliary complications
No full textBACKGROUND: To assess the diagnostic value of magnetic resonance cholangiography
(MRC) when evaluating biliary complications in a large series of liver
transplants.
METHODS: One hundred and twenty-nine patients prospectively underwent magnetic
resonance (MR) imaging and MR cholangiography at 1.5-T device after orthotopic
liver transplantation (OLT). After the preliminary acquisition of axial T1- and
T2-weighted images, MRC involved respiratory-triggered, thin-slab (2 mm), heavily
T2-weighted fast spin-echo and breath-hold, thick-slab (10-50 mm), single-shot
T2-weighted sequences. MR images were blindly evaluated by two experienced
readers in conference to determine the biliary anatomy and the presence of
complications, whose final diagnosis was based on endoscopic retrograde
cholangiography, percutaneous trans-hepatic cholangiography, and by integrating
clinical follow-up with ultrasound and/or MR findings.
RESULTS: Biliary complications were found in 60 patients (46.5%) and were
represented by ischemic-type biliary lesions (n=21); anastomotic strictures
(n=13); non-anastomotic strictures (n=5); anastomotic strictures associated to
lithiasis (n=6); lithiasis (n=6); papillary dysfunctions (n=9). The sensitivity,
specificity, positive predictive value, and negative predictive value of the
reviewers for the detection of all types of biliary complications in patients
with OLT were 98%, 94%, 94%, and 98%, respectively.
CONCLUSIONS: MRC is a reliable technique for detecting post-OLT biliary
complications and should be recommended before planning therapeutic
interventions
Focal nodular hyperplasia of the liver: diffusion and perfusion MRI characteristics.
Full text linkPurpose: To present diffusion and perfusion magnetic resonance imaging (MRI) characteristics of focal nodular hyperplasia (FNH) of the liver. Materials and Methods: Thirty-five patients with 52 FNHs (21 were pathologically-confirmed) underwent MRI at 1.5-T device. MR diffusion [diffusion-weighted imaging (DWI)] was performed using a free-breathing single-shot, spin-echo, echo-planar sequence with b gradient factor value of 500 s/mm2. MR perfusion [perfusion-weighted imaging (PWI)] consisted of a 3D free-breathing LAVA sequence repeated up to 5 minutes after injection of 7 mL Gd-BOPTA (MultiHance, Bracco, Italy) and 20 mL saline flush at a flow rate of 4 mL/s. Apparent diffusion coefficient (ADC) and time-signal intensity curve (TSIC) were obtained for both normal liver and each FNH by two reviewers in conference; maximum enhancement (ME) percentage, time to peak enhancement (TTP), and maximal slope (MS) were also calculated. Results: On DWI mean ADC value was 1.624×10-3 mm2/s for normal liver and 1.629×10-3 mm2/s for FNH. ADC value for each FNH and the normal liver was not statistically different (P=.936). On PWI, TSIC-Type 1 (quick and marked enhancement and quick decay followed by slowly decaying) was observed in all 52 FNHs, and TSIC-Type 2 (fast enhancement followed by slowly decaying plateau) in all normal livers. The mean ME, TTP and MS values were significantly different for FNH and normal liver (P=.005). Conclusion: FNHs of the liver showed typical diffusion and perfusion MRI characteristics in all cases. On the ADC map, we could get similar value between the FNHs and the background parenchyma. On the perfusion imaging, FNHs showed a different pattern distinguished from the background liver
ISCHEMIC-TYPE BILIARY LESIONS FOLLOWING LIVER TRANSPLANTATIONS: EVALUATION WITH MR CHOLANGIOGRAPHY
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