Vessel-Guided Mesohepatectomy for Liver Partition and Staged Major Parenchyma-Sparing Hepatectomies with Super-Selective Portal Vein Embolization or Enhanced ALPPS to Achieve R0 Resection for Colorectal Liver Metastases at the Hepatocaval Confluence.

Background. R0 minor parenchyma-sparing hepatectomy (PSH) is feasible for colorectal liver metastases (CRLM) in contact with hepatic veins (HV) at hepatocaval confluence since HV can be reconstructed, but in the case of contact with the first-order glissonean pedicle (GP), major hepatectomy is mandatory. To pursue an R0 parenchyma-sparing policy, we proposed vessel-guided mesohepatectomy for liver partition (MLP) and eventually combination with liver augmentation techniques for staged major PSH. Methods. We analyzed 15 consecutive vessel-guided MLPs for CRLM at the hepatocaval confluence. Patients had a median of 11 (range: 0-67) lesions with a median diameter of 3.5 cm (range: 0.0-8.0), bilateral in 73% of cases. Results. Grade IIIb or more complications occurred in 13%, median hospital stay was 14 (range: 6-62) days, 90-day mortality was 0%. After a median follow-up of 17.5 months, 1-year OS and RFS were 92% and 62%. In nine (64%) patients, MLP was combined with portal vein embolization (PVE) or ALPPS to perform staged R0 major PSH. Future liver remnant (FLR) volume increased from a median of 15% (range: 7-20%) up to 41% (range: 37-69%). Super-selective PVE was performed in three (33%) patients and enhanced ALPPS (e-ALPPS) in six (66%). In two e-ALPPS an intermediate stage of deportalized liver PSH was necessary to achieve adequate FLR volume. Conclusions. Vessel-guided MLP may transform the liver in a paired organ. In selected cases of multiple bilobar CRLM, to guarantee oncological radicality (R0), major PSH is feasible combining advanced surgical parenchyma sparing with liver augmentation techniques when FLR volume is insufficient.

Impact of baseline gadoxetic acid-enhanced liver magnetic resonance and diffusion-weighted imaging in resectable colorectal liver metastases: A prospective, monocentric study.

BACKGROUND: Liver magnetic resonance imaging (MRI) utilizing hepatocyte-specific contrast agent and diffusion-weighted imaging (DWI) is currently used to properly stage colorectal liver metastases (CRLM) in patients candidate to liver surgery. However, the added value of liver MRI in choosing the treatment strategy in resectable CRLM over computed tomography (CT)-scan is not clear. PATIENTS AND METHODS: This is a prospective monocentric collection of consecutive cases of patients with CRLM conceived with the aim to assess the added value of liver MRI in changing the initial treatment strategy planned according to CT-scan. Potential changes in the initially planned strategy were defined as: - from upfront surgery to perioperative chemotherapy (fluoropyrimidine and oxaliplatin) - from upfront surgery to first-line systemic therapy (doublet or triplet plus a biological agent) - from perioperative chemotherapy to first-line systemic therapy. Hypothesising that MRI may induce a change in the choice of the treatment strategy in the 20% of cases (alternative hypothesis), against a null hypothesis of 5%, with one-tailed alpha and beta errors of 0.05 and 0.20 respectively, 27 patients were needed. The added value of liver MRI would have been considered clinically meaningful if at least 4 changes in the treatment strategy were observed. RESULTS: Among 27 enrolled patients, upfront surgery and perioperative chemotherapy strategies were chosen in 17 (63%) and 10 (37%) cases, respectively, based on CT-scan. After liver MRI, additional liver lesions were found in 8 patients (30%) and the initial strategy was changed in 7 patients (26%) (4 initially deemed candidate to upfront surgery and 3 initially sent to perioperative chemotherapy) that were treated with first-line systemic therapy. CONCLUSIONS: Our results support the indication of the current guidelines on the routine use of liver MRI in the initial workup of patients with resectable CRLM with an MRI-driven changes of initial treatment plan in a relevant percentage of cases.

Gadoxetate Disodium-Enhanced MR Cholangiography for Evaluation of Biliary-Enteric Anastomoses: Added Value Beyond Conventional T2-Weighted Images.

OBJECTIVE. The objective of our study was to evaluate image quality and reader confidence in MR cholangiography of bile ducts using conventional T2-weighted MR cholangiography alone in comparison with T2-weighted MR cholangiography and gadoxetate disodium-enhanced MR cholangiography in a series of patients with biliary-enteric anastomosis (BEA). SUBJECTS AND METHODS. Fifty patients with BEA and clinically and sonographically suspected complications underwent 1.5-T MRI. After acquisition of T1- and T2-weighted images, conventional MR cholangiography was performed using 3D fast relaxation fast spin-echo (FRFSE) and single-shot fast spin-echo (SSFSE) T2-weighted sequences (image set 1). In each patient, a 3D fat-suppressed Liver Acquisition with Volume Acceleration (LAVA) sequence was performed before and 15, 20, 25, 30, and 40 minutes after IV administration of 0.1 mL/kg of gadoxetate disodium (Primovist) (image set 2). Two radiologists in consensus evaluated image quality in the anatomic segments of the biliary tract and recorded diagnostic confidence scores for image set 1 alone and image sets 1 and 2 together. MRI findings were compared with postsurgical specimen if surgery was performed, conventional cholangiography, or 12 months of imaging follow-up. RESULTS. A significant improvement in image quality for visualization of all biliary segments was found using gadoxetate disodium-enhanced MR cholangiography in comparison with T2-weighted MR cholangiography alone. Readers judged diagnostic confidence of image set 1 alone and image sets 1 and 2 together as very confident in three and 37 cases, confident in 30 and 11, not confident in 14 and one, and not confident at all in three and 1, respectively. Concordance between image set 1 alone and image sets 1 and 2 together and the reference standard results was present in 23 of 50 cases (46%) and 47 of 50 cases (94%), respectively (p < 0.0001). CONCLUSION. Gadoxetate disodium-enhanced MR cholangiography can improve image quality for visualization of the biliary tract and further enhanced the diagnostic performance of conventional T2-weighted MR cholangiography in the evaluation of patients with BEA.

Biliary complications following orthotopic liver transplantation: May contrast-enhanced MR Cholangiography provide additional information?

PURPOSE: 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.

Focal nodular hyperplasia of the liver: diffusion and perfusion MRI characteristics.

PURPOSE: 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) mm(2)/s for normal liver and 1.629×10(-3) mm(2)/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.

Diffusion-weighted MRI in the characterization of cystic pancreatic lesions: usefulness of ADC values.

PURPOSE: To evaluate the usefulness of diffusion-weighted magnetic resonance imaging (DW-MRI) in the differentiation of cystic pancreatic lesions. MATERIALS AND METHODS: Institutional review board approval was obtained, and written informed consent was taken from all enrolled subjects. Fifty-four patients with cystic pancreatic lesions of at least 1 cm in diameter (range:10-96 mm) at ultrasonography and/or computed tomography and 10 normal subjects underwent MRI at 1.5 T. These subjects included thirty-four patients with intraductal papillary mucinous tumors (IPMTs), 10 with pseudocysts, 5 with serous cystoadenoma and 5 with mucinous cystoadenoma. The MR protocol included axial T1w and T2w sequences and coronal MR cholangiopancreatography images. DW-MRI was performed using a breath-hold single-shot echo-planar sequence with a b gradient factor value of 500 s/mm(2) in the three orthogonal axes. Apparent diffusion coefficient (ADC) was calculated for cerebrospinal fluid, normal pancreatic parenchyma, and for each focal pancreatic lesion. Imaging results were correlated with endoscopic retrograde cholangiopancreatography, endoscopic ultrasound-guided fine needle aspiration, surgery and/or imaging follow-up. RESULTS: Mean ADC value was 4.1×10(-3) mm(2)/s for cerebrospinal fluid, 1.73×10(-3) mm(2)/s for normal pancreatic parenchyma, 4.09×10(-3) mm(2)/s for IPMT, 3.89×10(-3) mm(2)/s for mucinous cystoadenoma, 3.65×10(-3) mm(2)/s for serous cystoadenoma and 2.83×10(-3) mm(2)/s for pseudocyst. Mean ADC values of each of the different types of pancreatic lesions were statistically different (P<.05). CONCLUSION: DW-MRI may be helpful in the differential diagnosis of cystic pancreatic lesions.

MR cholangiography in orthotopic liver transplantation: sensitivity and specificity in detecting biliary complications.

BACKGROUND: 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.

Secretin-stimulated MR cholangio-pancreatography in the evaluation of asymptomatic patients with non-specific pancreatic hyperenzymemia.

PURPOSE: To assess the diagnostic value of secretin-stimulated MRCP (SS-MRCP) compared with conventional MRCP in asymptomatic patients with mild elevations of pancreatic enzymes. MATERIALS AND METHODS: Eighty asymptomatic patients with pancreatic hyperenzymemia underwent MR imaging at 1.5T-device (Signa EXCITE, GE Healthcare). After the acquisition of axial T1w,T2w sequences, and conventional MRCP, SS-MRCP was performed using a single-slice coronal breath-hold, thick-slab, SSFSE T2w sequence, repeated every 30s up to 15 min following intravenous injection of secretin (Secrelux, Sanochemia). RESULTS: On the basis of the standards of reference, our final diagnoses were: negative findings (n=23), pancreas divisum (n=22), mild chronic pancreatitis (n=14), inflammatory ampullary stenosis (n=3), juxtapapillary duodenal diverticulum (n=1), small cystic lesions (<1cm) (n=22; 5/22 cases associated with pancreas divisum). The image quality of SS-MRCP was significantly higher than that of conventional MRCP (p<0.0001). Standards of reference did not differ significantly from of SS-MRCP findings (p=0.5), while was statistically different from those of conventional MRCP (p<0.0001). A significant difference was found between conventional MRCP and SS-MRCP findings (p<0.0001). CONCLUSION: In asymptomatic patients with non-specific pancreatic hyperenzymemia SS-MRCP may represent the best non-invasive diagnostic technique, since it gives morphological and functional information.

Complications after liver transplantation: evaluation with magnetic resonance imaging, magnetic resonance cholangiography, and 3-dimensional contrast-enhanced magnetic resonance angiography in a single session.

OBJECTIVE: To evaluate a comprehensive magnetic resonance imaging (MRI) protocol as noninvasive diagnostic modality for simultaneous detection of parenchymal, biliary, and vascular complications after liver transplantation. METHODS: Fifty-two liver transplant recipients suspected to have parenchymal, biliary, and (or) vascular complications underwent our MRI protocol at 1.5T unit using a phased array coil. After preliminary acquisition of axial T1w and T2w sequences, magnetic resonance cholangiography (MRC) was performed through a breath-hold, thin- and thick-slab, single-shot T2w sequence in the coronal plane. Contrast-enhanced magnetic resonance angiography (CEMRA) was obtained using a 3-dimensional coronal spoiled gradient-echo sequence, which enabled acquisition of 32 partitions 2.0 mm thick. A fixed dose of 20 ml gadobenate dimeglumine was administered at 2 mL/s. A post-contrast T1w sequence was also performed. Two observers in conference reviewed source images and 3-dimensional reconstructions to determine the presence of parenchymal, biliary, and vascular complications. MRI findings were correlated with surgery, endoscopic retrograde cholangiography (ERC), biopsy, digital subtraction angiography (DSA), and imaging follow-up. RESULTS: MRI revealed abnormal findings in 32 out of 52 patients (61%), including biliary complications (anastomotic and nonanastomotic strictures, and lithiasis) in 31, vascular disease (hepatic artery stenosis and thrombosis) in 9, and evidence of hepatic abscess and hematoma in 2. ERC confirmed findings of MRC in 30 cases, but suggested disease underestimation in 2. DSA confirmed 7 magnetic resonance angiogram (MRA) findings, but suggested disease overestimation in 2. CONCLUSION: MRI combined with MRC and CEMRA can provide a comprehensive assessment of parenchymal, biliary, and vascular complications in most recipients of liver transplantation.

Pancreatic transplants: secretin-stimulated MR pancreatography.

BACKGROUND: Our study was aimed to evaluate the functional status of pancreatic transplants using dynamic MR pancreatography after secretin stimulation. METHODS: Thirteen asymptomatic patients previously submitted to isolated pancreas (n = 6) or combined kidney-pancreas (n = 7) transplantation, with enteric-portal pancreatic drainage, underwent MR examination at 1.5 T using a phased-array coil. After the acquisition of axial and coronal T1- and T2-weighted sequences, dynamic MR pancreatography was performed using a coronal breath-hold, thick-slab (40-60 mm), single-shot T2-weighted fast spin-echo sequence. After the intravenous administration of secretin (Secrelux, Sanochemia; 1 cU/kg body/weight), a single-slice image acquisition was repeated every 30 s up to 15 min. We estimated the calibre changes of the pancreatic ductal system and the filling of the donor's duodenum on the basis of pancreatic secretion after secretin stimulation, also evaluated by using a mean signal intensity/time histogram in a chosen region of interest including the transplanted pancreas and the connected small bowel. RESULTS: All patients well tolerated the examination, and no side effects were reported after secretin administration. In 12/13 cases, a significant increase (more than 1 mm) in the diameter of the mean pancreatic duct was observed after secretin stimulation; in all patients, a noticeable filling of the duodenal graft was demonstrated during dynamic MR pancreatography on both qualitative and quantitative analyses. CONCLUSIONS: Dynamic MR imaging after secretin administration allows non-invasive evaluation of exocrine function of the pancreatic transplants and could be used to differentiate patients with graft rejection from those with normal graft function.

Mangafodipir trisodium-enhanced MR imaging of pancreatic disease.

Our study aimed to assess the diagnostic capabilities of mangafodipir trisodium-enhanced MRI for the evaluation of pancreatic disease. Sixty-three patients suspected of having pancreatic disease underwent MRI with a 1.5-T device. After the acquisition of axial and coronal T2-weighted sequences, the MR protocol included T1-weighted fat-suppressed breath-hold SPGR images obtained before and 30 min after the infusion of Mn-DPDP (Teslascan). The detection of a focal pancreatic lesion and its intensity were evaluated in consensus by two observers, who also attempted to characterize each lesion as benign or malignant. The reviewers were blinded to patient identification and all clinical, laboratory and previous imaging findings. MR imaging results were correlated with surgery (n=37), laparoscopy (n=1), biopsy (n=2) and imaging follow-up (n=22). Sixty-two subjects were effectively included in our analysis because one patient was lost to follow-up; final malignant and benign diagnoses were determined in 22 (35%) and 29 (47%) of the patients, respectively. The level of confidence in the diagnosis of the pancreatic lesion was significantly increased by the administration of Mn-DPDP as demonstrated by ROC analysis of unenhanced and post-contrast image sets (P=0.009). Overall, on the basis of observers' readings, MR assessment of pancreatic disease resulted in 57 correct diagnoses (accuracy, 92%) and five (8%) incorrect diagnoses. The sensitivity, specificity, positive predictive value and negative predictive value of the reviewers for the detection of pancreatic lesions and for the differentiation between benign and malignant masses were 91% (95% CI: 84 and 98%), 93% (95% CI: 86 and 99%), 87% (95% CI: 79 and 95%) and 95% (95% CI: 89 and 100%), respectively. Mn-DPDP-enhanced MRI is an effective diagnostic tool for evaluating pancreatic disease.

MR enteroclysis using iron oxide particles (ferristene) as an endoluminal contrast agent: an open phase III trial.

To evaluate efficacy and safety of a superparamagnetic iron oxide contrast agent (ferristene) as an endoluminal contrast medium for magnetic resonance (MR) enteroclysis in a phase III trial. Twenty-three patients with history of known or suspected small bowel Crohn's disease underwent MR imaging of the abdomen at 0.5 T unit. The imaging protocol included two phases: the first one without administration of any contrast agent and the second one, where the small bowel was filled by enteroclysis with 800 ml of the luminal iron oxide contrast medium and Gd-DTPA (0.1 mmol/Kg) was administered intravenously. Axial Spin-Echo (SE) T1-weighted (T1w), proton-density and T2w images, sagittal and coronal SE T1w and Short TI Inversion Recovery (STIR) sequences were subsequently obtained. Three investigators blindly evaluated images to determine small bowel distribution of ferristene, presence of artifacts, delineation of bowel lesion/wall and the diagnostic value of ferristene combined with gadolinium. Pre- and postcontrast signal intensity measurements of bowel lesion/wall, bowel lumen and background noise were also calculated. Three patients withdrew before the procedure, therefore 20 patients were effectively included in the study. No significant difference between the three investigators' evaluations of the improvement of the diagnostic information was found (percentage of improvement of 90% with 95% confidence limits of 68% and 99%). A statistically significant difference between the first and third investigators was found for grading of quality of delineation of bowel lesion/wall. Signal intensity measures showed a significant increase of the bowel lesion/wall and background noise/lesion for the SE T1w images. No serious adverse event was reported in our series. MR enteroclysis using ferristene as an endoluminal contrast agent appears to be a safe and efficient procedure for the study of the small bowel.