Undetectable inferior petrosal sinus levels of PTH-related peptide (PTHrP) in patients with ACTH-dependent Cushing's disease.

PTH-related peptide (PTHrP), a member of the PTH family, is widely expressed in foetal and adult tissues, and it has been found in benign and malignant tumors, including GH and PRL-secreting adenomas. Conflicting data are reported in literature on serum PTHrP concentrations in patients with Cushing's disease. The aim of the present study was to further evaluate peripheral and inferior petrosal sinus (IPS) serum PTHrP concentrations before and after CRH, in a group of consecutive patients with ACTH-dependent Cushing's disease. Nine patients with active ACTH-dependent Cushing's disease (8 women and 1 man, age +/- SD 41 +/- 13 yr) were submitted to peripheral and IPS sampling under fluoroscopic control before and after iv administration of CRH. All patients were subsequently submitted to transsphenoidal surgery and an ACTH-secreting microadenoma was found in all cases. In all patients, serum IPS and peripheral ACTH measurement were in keeping with the diagnosis of ACTH-dependent Cushing's disease. Serum PTHrP concentrations before and after CRH stimulation were below the sensitivity limit of the assay in all samples, and no gradient between IPS and peripheral sampling was observed. Our data, combined with others reported in literature, indicate that PTHrP release by ACTH-secreting tumors is not a common occurrence. Therefore, we conclude that IPS and peripheral PTHrP are of little clinical usefulness.

Surveillance and rescue of pancreas grafts.

BACKGROUND: Technical failure rates are higher for pancreas allografts (PA) compared with other solid organs. Posttransplant surveillance and prompt availability of rescue teams with multidisciplinary expertise both contribute to improve this result. We herein report a single institution's experience with posttransplant surveillance and rescue of PA. METHODS: A retrospective survey was performed of a consecutive series of 177 whole organ pancreas transplants in 173 patients. Antithrombotic prophylaxis was used in all recipients and tailored on anticipated individual risk of thrombosis. During the first posttransplant week, all PA were monitored with daily Doppler ultrasonography. Surgical complications were defined as all adverse events requiring relaparotomy during the initial hospital stay or the first 3 posttransplant months. RESULTS: A total of 26 relaparotomies were performed in 25 patients (14.7%). One recipient needed two relaparotomies (0.6%). Graft rescue was attempted in patients without permanent parenchymal damage at repeat surgery and in 12 recipients diagnosed with nonocclusive vascular thrombosis. Overall 25 grafts (96.3%) were rescued and one was lost. One-year recipient and graft survivals in patients with versus without complications potentially leading to allograft loss were 92.6% and 63.0% versus 94.4% and 94.3%, respectively. Excluding complications for which graft rescue was not possible, 1-year graft survival rate increased to 78.7%. CONCLUSIONS: Close posttransplant surveillance can allow rescue of a relevant proportion of PA developing nonocclusive venous thrombosis or other surgical complications. Further improvement awaits better understanding of biological reasons for posttransplant complications jeopardizing PA survival and the development of more effective preventive measures.

Diagnosis and treatment of hepatic artery stenosis after orthotopic liver transplantation.

PURPOSE: The purpose of this study was to evaluate the accuracy of Multidetector Computed Tomographic Angiography (MDCTA) to detect hepatic artery (HA) stenosis after orthotopic liver transplantation (OLT) and the efficacy of treatment using percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: Twenty-two consecutive patients with OLT underwent MDCTA for evaluation of HA, followed by digital subtraction angiography (DSA) (gold standard). Source images (Ax) were processed, obtaining multiplanar reformations (MPRs), maximum intensity projections (MIPs), and volume renderings (VRs). Images were evaluated to identify the following: (1) arterial depiction (celiac axis, anastomosis, and left [LHA] and right [RHA] HA), (2) detection of stenoses, and (3) grading of stenoses. Indications for PTA were set at MDCTA and DSA, and PTA was performed when appropriate. RESULTS: MDCTA depicted the celiac axis and anastomoses in all patients; LHA and RHA were visualized in 21 of 22 patients with Ax, MPRs, and MIPs, and in 17 of 22 with VRs. All reconstruction modalities enabled correct diagnosis of celiac (n = 3) and anastomotic stenoses (n = 14). Of 6 LHA and RHA stenoses, 4 (66.7%) were visualized with Ax, MPRs, and VRs, and 5 (83.3%) were visualized with MIPs. Stenosis was overestimated in 9 (39.1%) cases with VRs and in 3 (13%) with the other modalities. PTA was performed in 8 cases, with 1 case of arterial dissection requiring re-OLT. At a median follow-up of 28 months, the primary and secondary patency rates were 71.4% (5 of 7) and 85.7% (6 of 7), respectively. CONCLUSIONS: MDCTA and accurate postprocessing enable confident depiction of the arterial anatomy and detection of stenosis after OLT. PTA is safe and allows allograft saving, at least until another suitable donor becomes available.

Rescue of kidney and pancreas grafts with complex vascular lesions.

BACKGROUND: The organ shortage mandates that grafts with complex vascular lesions be considered for graft rescue. METHODS: Surgical graft rescue was attempted in 8 patients bearing 8 kidneys and 2 pancreata that showed complex vascular lesions deemed not suitable for interventional radiology procedures. RESULTS: All procedures but 1 were performed under elective conditions. Seven grafts were repaired in situ, while cooling the organ through retrograde venous perfusion, and 3 kidneys were explanted, repaired extracorporeally, and retransplanted. All vascular reconstructions remain patent after a mean follow-up period of 3.3 years (+/-2.1 years). CONCLUSIONS: Careful patient selection, multidisciplinary evaluation, and personalized surgical technique may allow the rescue of kidney and pancreas grafts with complex vascular lesions that, otherwise, would be lost.

Hepatic resection after liver transplantation as a graft-saving procedure: indication criteria, timing and outcome.

BACKGROUND: Hepatic resection is uncommon after liver transplantation (LT), but can be a graft-saving procedure in selected cases. Herein we describe the criteria, outcome, and timing of this procedure in our series. METHODS: Between January 1996 and December 2002, 397 LTs were performed in 367 recipients, of whom 12 patients (3.2%) subsequently underwent liver graft resections because of ischemic-type biliary lesions (ITBLs) (n = 5, 41.6%), segmental hepatic artery thrombosis (S-HAT)(n = 3, 25%), recurrent hepatocellular carcinoma (HCC) (n = 2, 16.6%), liver abscess (n = 1, 8.3%), or liver trauma (n = 1, 8.3%). The patients were divided into group 1 (n = 3 all with S-HAT) who underwent early resections (within 3 months of LT), and group 2 (n = 9) who underwent late resections (after 3 months). The outcomes and postoperative mortality ratio (within 30 days) were compared. RESULTS: The resections consisted of four left lobectomies, three right hepatectomies, two extended right hepatectomies, one segmentectomy, one anterior trisegmentectomy, and one right lateral sectoriectomy. The perioperative mortality rate was 66.6% in group 1 (one case of myocardial infarction and one of sepsis), and 22% in group 2 (one case of sepsis and one of hepatic failure). CONCLUSIONS: Late resections in stable patients with damage confined to the graft yield good prognosis. Even major resections are feasible graft-saving procedures. In contrast, early hepatic resections in S-HAT are associated with a worse outcome. Retransplantation should be considered the first-choice option. Sepsis significantly affects the postsurgical course.

Role of interventional radiology in the management of vascular complications after liver transplantation.

The purpose of this study is to review the role of the percutaneous interventional procedures in the treatment of vascular complications after orthotopic liver transplantations (OLT). Vascular complications, such as arterial stenosis and venous thrombosis, which occur in approximately 1% to 10% of liver transplant patients, are associated with a higher risk of graft dysfunction. Percutaneous interventional procedures, including angioplasty, local thrombolysis, and embolization, are useful to manage these complications. A reduced blood loss and a low incidence of procedural complications allow for rapid recovery. Hepatic arterial and portal vein anastomotic stenosis can be treated effectively by means of balloon dilation; stenting has also been proposed, particularly for venous complications. Infusional local thrombolysis may be useful in venous thrombosis. Arteriovenous fistulas, occurring at the level of the anastomosis or after liver biopsy, require intraarterial embolization using microcoils or gelfoam. Timing of the intervention for the treatment of ischemic complications is of outmost importance to guarantee liver functional recovery and avoid irreversible parenchymal injuries. Other interventional procedures may be extremely useful to manage portal hypertension after OLT; for example, by creation of transjugular portosystemic shunts, or, in the case of associated hypersplenism, transarterial embolization of the splenic artery. Finally, in patients with recurrent hepatitis, the transjugular approach has been shown to be safe and effective for liver biopsy, whereas transarterial chemoembolization may be extremely useful to treat recurrent hepatocarcinoma.

Surgical complications after liver transplantation.

AIM: The number of liver transplantations in Italy has steadily increased over the last 10 years as a result of the use of donors aged more than 60 years. The use of organs with a reduced functional reserve has been compensated for by improvements in immunosuppressive therapy, surgical techniques and the management of postoperative complications. This article describes the incidence and treatment of the main surgical complications after liver transplantation. METHODS: Between January 1996 and June 2003, 398 patients received 430 transplants at our Centre. Thirty-seven early relaparotomies were performed (8.6%), including 12 retransplantation (2.8%). The 1-, 3- and 5-year actuarial survival of the patients was 79.8%, 72.2% and 67.5%, and that of the grafts was 75.9%, 68% and 63.4%. Perioperative mortality was 10.5% (with no intraoperative deaths). RESULTS: The overall incidence of biliary complications was 31.6%, 9.1% of which were due to the removal of the Kehr tube. There were 42 (9.8%) anastomotic stenoses, 5 (1.2%) extra-anastomotic stenoses, 1 (0.2%) anastomotic leak, 5 (1.2%) extra-anastomotic leaks, and 19 (4.4%) ischemic-type biliary lesions. The overall incidence of vascular complications was 6.9%: 7 (1.6%) cases of hepatic artery thrombosis, 17 (4.0%) arterial stenoses, 1 (0.2%) arterial pseudoaneurysm, 4 (0.9%) cases of portal thromboses and 1 (0.2%) case of caval laminar thrombosis. Eight patients (1.9%) developed massive and persistent post-transplant ascites and/or hydrothorax. CONCLUSION: The use of donors aged more than 60 years makes it possible to maintain high standards of patient and graft survival that is not only due to the optimisation of immunosuppressive protocols, but also to improvements in surgical techniques, intensive care and the management of surgical complications.

Management of massive and persistent ascites and/or hydrothorax after liver transplantation.

PURPOSE: To describe the results of the treatment of eight liver transplantation (LT) patients subsequently developing large volumes of long-lasting ascites. PATIENTS AND METHODS: Between August 1996 and February 2003, 405 LTs were performed in 375 patients, eight (1.97%) of whom (six men and two women of mean age of 55.4 +/- 5.2 years) subsequently developed massive (> 500 mL/d) and persistent ascites and/or hydrothorax. All patients were HCV positive. The mean age of the liver donors was 66.8 +/- 21.9 years. All LTs were performed by replacement of the recipient retrohepatic vena cava. RESULTS: The eight patients displayed sinusoidal portal hypertension related to biopsy-proven recurrence of HCV infection. Mean wedged hepatic venous pressure was 14.9 +/- 5.1 mm Hg and mean portal vein/right atrial pressure gradient (PAPG) was 17.3 +/- 4.8 mm Hg. In two patients, the ascites appeared the day after LT; in the remaining six, ascites and/or hydrothorax appeared after 342.3 +/- 167.7 days. Seven patients with a mean PAPG of 18.4 +/- 3.9 mm Hg and a mean plasma/ascites albumin concentration gradient of 2.8 +/- 0.3 g/L were treated by means of a trans-jugular intrahepatic portosystemic shunt TIPS, and one (with a PAPG of 9 mm Hg and a plasma/ascites albumin concentration gradient of 1.38 g/L) by means of spleen arterial embolisation. After a mean follow-up of 558 +/- 147.2 days, the ascites and/or hydrothorax have resolved in five patients (62.5%), one (12.5%) has stable ascites not requiring paracentesis, and two (25%) have died of multiorgan failure. CONCLUSIONS: These data suggest the efficacy of the aggressive treatment of massive and persistent ascites and/or hydrothorax.

Duplex ultrasonographic study of the renal arteries before and after renal artery stenting.

The aim of our study was to evaluate feasibility and accuracy of colour-coded duplex US in the detection of renal artery stenosis before and after stenting. Eighty-four patients (23 women, 61 men; mean age 64 years) with significant renal artery stenosis were studied with Doppler US, before and after stenting. A combined anterior and translumbar approach was used to visualise the renal arteries. Renal artery stenosis and in-stent restenosis were proved by the increase of renal peak systolic velocity (PSV) and reno-aortic ratio (RAR). Laboratory-specific threshold values of PSV and RAR were used to assess sensitivity and specificity of Doppler US. The renal arteries were visualised in all patients (feasibility 100%). A statistically significant difference of PSV and RAR was demonstrated between patent and stenotic renal arteries, before stenting, and between stenotic and stented renal arteries. No difference was demonstrated in cases of in-stent restenosis ( n=21). Before stenting, sensitivity of PSV and RAR was 93%, whereas specificity rates were 92 and 96%, respectively. After stenting sensitivity and specificity rates were, respectively, 90 and 93% for PSV, and 95 and 95% for RAR. Doppler US represents a feasible and reliable technique in the detection of renal artery stenosis and in-stent restenosis, although laboratory-specific threshold values are required to improve its accuracy.

Endoluminal treatment of abdominal aortic aneurysms.

BACKGROUND: We report our preliminary results with endovascular treatment of abdominal aortic aneurysms (AAA). METHODS: Between October 1998 and June 2000, 64 patients (62 male, two female; mean age = 70 years) underwent endovascular repair of AAA. Different types of prostheses were used, both bifurcated (n = 58) and straight (n = 6). We performed duplex sonography and spiral computed tomographic angiography (CTA) at discharge and at 3, 6, 12, and 18 months. Follow-up ranged from 1 to 20 months. RESULTS: All procedures were successful, except for three immediate and one late surgical conversions (6.2%). One patient died 14 days after immediate surgical conversion. At discharge, CTA showed 13 endoleaks: three resolved spontaneously, six persisted during follow-up, and four (one angioplasty and three embolizations) were treated successfully. Stenosis of an iliac branch occurred in one patient after 3 months and was successfully treated by angioplasty. Late endoleaks were detected by imaging follow-up in four cases, three at 1 year and one at 6 months, requiring deployment of distal extender cuffs (n = 2), a proximal cuff (n = 1), and lumbar embolization (n = 2). CONCLUSION: Our preliminary experience supports the efficacy of endovascular repair in selected patients, but strict and accurate follow-up is required.

Optical pattern recognition by use of a segmented semiconductor optical amplifier.

A technique for high-speed, all-optical pattern recognition based on cross correlation in a segmented semiconductor optical amplifier (SSOA) is presented. A counterpropagating pump-probe setup is used to perform cross correlation of the spatial gain-loss pattern in the SSOA with the optical data pattern (pump), and the result is read out with a counterpropagating probe. Cross correlation of 4-bit patterns at 85 Gbits/s is experimentally demonstrated. Simulations show reasonable agreement with experimental measurements and are used to address scalability to higher bit rates and longer data patterns.

Renal artery stenting in patients with a solitary functioning kidney.

PURPOSE: To retrospectively evaluate the results of renal artery stenting in patients with renovascular disease and a solitary functioning kidney. METHODS: Palmaz stents were placed in 16 patients with a solitary functioning kidney, renal artery stenosis, hypertension and renal failure. Stenoses were evaluated with color Doppler ultrasound, MR angiography and digital subtraction angiography (DSA). Indications for stenting were: recoil after percutaneous transluminal renal angioplasty (PTRA) (63%), arterial dissection after PTRA (13%) and primary stenting (25%). Immediate results were evaluated by DSA. On follow-up (6-36 months), patients underwent periodical evaluation of clinical conditions (blood pressure and serum creatinine level) and stent patency, by means of color Doppler ultrasound. RESULTS: Stent placement was successful in all patients (100%). Cumulative primary patency rate was: 100% at 1 day, 93.75% at 6 months, 81.25% at 12 months and 75% at 24 months. A significant reduction in diastolic blood pressure occurred (mean +/- SD 104 +/- 6 vs 92 +/- 3; p < 0.05); renal function improved or stabilized in over 80% of patients. However, there was no significant difference in the creatinine values before and after treatment (mean +/- SD 200 +/- 142 micromol/l vs 197 +/- 182 micromol/l; p > 0.05). CONCLUSION: Renal artery stenting, both after PTRA and as primary stenting, represents a safe procedure, able to preserve renal function in patients with a solitary functioning kidney.

Contrast-enhanced three-dimensional MR angiography in the assessment of subclavian artery diseases.

The purpose of this prospective study was to determine the potential diagnostic value of 3D breath-hold contrast-enhanced MRA (CEMRA) in the evaluation of subclavian artery pathology, and to compare CEMRA and digital subtraction angiography (DSA) findings. The study group included 50 patients with suspicion of subclavian artery pathology: 40 suspected steno-occlusive disease and 10 different vascular anomalies. The MRA examinations were performed on a 1.5-T system using fast 3D sequences. A fixed dose of 40 ml Gd-DTPA was administered at 2 ml/s after previous bolus tracking. Images were analyzed to assess: subclavian depiction; luminal changes; collateral branches; and feeders of arterial venous malformations (AVM). A multireader blinded fashion was used. The CEMRA revealed an optimal agreement with DSA findings in the different types of diseases. Sensitivity and specificity were 90 and 95%, respectively, in detecting steno-occlusive disease (including functional and arteritic stenoses), and 100 and 100%, respectively, in cases of vascular anomalies (dilation, kinking, anomalous origin and AVM). Contrast-enhanced MRA can be proposed as a non-invasive, robust technique for imaging subclavian pathologies with high diagnostic performance.

Spiral CT virtual endoscopy of abdominal arteries: clinical applications.

Virtual endoscopy enables the creation of endoluminal views of the aorta and its branches by processing spiral computed tomographic (CT) images, thereby allowing the preoperative and postoperative evaluations of abdominal aortic aneurysms, aneurysms of the splenic, celiac, and common iliac arteries, and renal artery stenoses. Moreover, it is helpful for verifying the position of stents and endoprostheses from within the aortic lumen. This method is a promising addition to spiral CT.

Do acute lesions of Wernicke's encephalopathy show contrast enhancement? Report of three cases and review of the literature.

Contrast medium was given intravenously to three nonalcoholic patients who underwent MRI or CT in the acute stage of Wernicke's encephalopathy. Lesions enhancement was not seen in one patient examined within 4 days of clinical onset, was mild in a another 3 days after clinical deterioration and marked in a patient examined 12 days after admission. Contrast enhancement of lesions was present in half of 12 cases of acute disease reported previously. There was a substantial overlap in the time interval between clinical onset and contrast-enhanced CT or MRI in the groups of enhancing and nonenhancing lesions. Since contrast enhancement may be absent in acute WE, proton-density and T2-weighted images are more useful for diagnosis of this reversible but potentially fatal condition.

Identification of the feeding arteries of spinal vascular lesions via phase-contrast MR angiography with three-dimensional acquisition and phase display.

PURPOSE: To determine whether identification of the feeding arteries of spinal vascular lesions with phase-contrast MR angiography benefits from the higher spatial resolution of three-dimensional (volume) acquisitions and flow-direction information provided by the phase reconstruction of two-dimensional acquisitions. METHODS: Fifteen patients with high- or low-flow spinal vascular lesions proved by spinal arteriography underwent MR angiography with phase-contrast techniques. Arteriographic and MR angiographic studies were reviewed to identify the arterial feeders of spinal vascular lesions. RESULTS: On modulus reconstructions of coronal 2-D or 3-D acquisitions, three of four arteries feeding high-flow lesions and three of 14 arteries feeding low-flow lesions were identified as hypertrophic vessels joining the parent intercostal or cervical arteries. Of 11 intradural veins draining dural arteriovenous fistulas, three were identified on coronal 2-D acquisitions and six on coronal 3-D acquisitions as vessels that coursed from a neural foramen to a midline tangle of vessels. Phase reconstruction showed ascending and descending flow patterns in two patients with intramedullary arteriovenous malformations, and diverging flow in perimedullary veins draining a hemangioblastoma. In nine patients with dural arteriovenous fistulas, phase reconstruction provided information as to the level of the arterial feeders. Phase reconstruction in coronal plane acquisitions also provided evidence of centripetal flow. CONCLUSION: Three-dimensional acquisitions and phase display of 2-D acquisitions improved the visibility of arterial pedicles of spinal vascular lesions at phase-contrast MR angiography.

Ex-vivo MR imaging of liver intracellular contrast agents.

The objective is to evaluate whether an ex-vivo model can be used to test intracellular contrast agents for MR imaging of the liver. T1 weighted inversion recovery, proton density spin echo and T2* weighted gradient echo images of the liver were acquired at 0.5 T in 10 rats before and 30 min after intravenous injection of 0.075 mmol/kg Gadolinium benzyloxypropionictetraacetate (Gd-BOPTA, n = 5) or 0.015 mmol/kg dextran magnetite (DM, n = 5), Four additional animals served as controls. After exsanguination and perfusion with saline and formalin, specimens of the liver and brain were embedded in an agar gel and examined with MR imaging one to three weeks later using the same protocol. In-vivo, the mean liver signal enhancement caused by Gd-BOPTA in T1, proton density and T2* weighted images was +23%, +28% and -70%, respectively. The mean liver signal enhancement caused by DM was -71%, -76% and -94%. In-vitro, no signal change was seen in the brain of animals injected with Gd-BOPTA and DM as compared to controls. Liver signal was increased by Gd-BOPTA and decreased by DM. Mean liver enhancement rate induced by Gd-BOPTA was +22%, +5% and +27% for T1, proton density and T2* weighted images, respectively. Mean liver enhancement rate induced by DM was -27%, -19% and -31%. MR imaging signal changes induced by liver intracellular contrast agents are still appreciable in an ex-vivo model. The latter might be useful for for preliminary investigation of intracellular contrast agents for MR imaging of the liver.