Gerd Noeldge

Preoperative Staging of Renal Cell Carcinoma With Inferior Vena Cava Thrombus Using Multidetector Ct and Mri: Prospective Study With Histopathological Correlation

Objective: To evaluate the accuracy of multidetector computed tomography (CT) and magnetic resonance imaging (MRI) in staging and estimating renal carcinomas with caval thrombus. Methods: Initially, 23 patients with suspected caval thrombi were admitted into this prospective study. Triphasic CT imaging was performed using a multidetector CT with a reconstructed slice thickness of 2 mm. 3D CT reconstructions were used to improve surgical planning. MRI protocol included: a transversal T1-weighted GE sequence with and without Gd-DTPA, a transversal T2-weighted respiratory-gated TSE, and a coronal T1-weighted GE sequence with Gd-DTPA and fat saturation. In addition, a multiphase 3D angiography was performed after Gd-DTPA injection. Patients were divided into 3 groups: caval thrombus below the insertion of the hepatic veins, within the intrahepatic vena cava, and intra-atrial extension. The results the tumor thrombus extension and staging results of 2 independent readers were correlated with surgical and histopathological staging. Results: Of the 23 patients admitted, CT and MR scans of 14/13 patients respectively were correlated with histopathological workup. CT thrombus detection sensitivity and specificity for both readers was 0.93 and 0.8 respectively. MRI sensitivity and specificity for both readers was 1.0/0.85 and 0.75. Readers I and II evaluated the uppermost extension of the cranial tumor thrombus by both CT and MRI. CT and MR accuracy was 78% and 72%, 88% and 76% respectively. Conclusion: In cases of a suspected tumor thrombus, MRI and multidetector CT imaging showed similar staging results. Consequently, these staging modalities can be used to assess the extension of the tumor thrombus.

The transjugular intrahepatic portosystemic stent-shunt (TIPSS): results of a pilot study.

The new concept of TIPSS (Transjugular Intrahepatic Portosystemic Stent-Shunt) using the Palmaz iliac stent was successfully accomplished in 9 patients with severe portal hypertension (7 alcoholic, 2 postinfectious liver cirrhosis) and histories of multiple life-threatening upper GI bleeding. All patients were considered noncandidates for surgical portal decompression. An intrahepatic central connection was made transjugularly between the right hepatic vein and the right portal vein in 8 patients and the left portal vein in 1. The portosystemic gradient dropped from an average of 29±7.2 mmHg to 17.8±2.9 mmHg immediately after, and to 15.7±2.8 mmHg at the latest follow-up control after the procedure. Seven patients survived the procedure and progressed to Childs A stage during the observation period of 1–10 months (mean 5 months). One patient died as a direct complication from the procedure, and another patient 11 days after the procedure from a severe nosocomial infection. In none of the surviving patients has bleeding from varices recurred or encephalopathic coma developed. In one patient the shunt diameter was moderately increased by a routine PTA catheter to further decrease the portosystemic gradient (23 to 14 mmHg) 3 months after the primary procedure. Autopsy in the two patients who died demonstrated open stent-shunts with early neoendothelial incorporation.

Diagnostic accuracy of staging renal cell carcinomas using multidetector-row computed tomography and magnetic resonance imaging: a prospective study with histopathologic correlation.

Objective: The aim of this prospective study is to compare the diagnostic accuracy of multidetector-row computed tomography (CT) and magnetic resonance imaging (MRI) in tumor staging of renal cell carcinomas. Methods: In a prospective study, 82 renal cell carcinomas were assessed for tumor staging before surgery using multidetector-row CT and MRI, the results of which were then correlated to histopathologic staging. Triphasic CT (noncontrast, arterial phase, and parenchymal phase) imaging was performed using multidetector-row CT with a reconstructed slice thickness of 2 mm. In MRI, a transverse T1-weighted gradient echo sequence with and without administration of Gd-DTPA, a transverse T2-weighted respiratory-gated turbo spin echo (TSE) sequence, and a coronal T1-weighted gradient echo sequence with Gd-DTPA were used. In addition, multiphasic 3-dimensional angiography after Gd-DTPA injection and a transverse T1-weighted fat-suppression sequence were performed. Results: With MRI, readers 1 and 2 correctly staged 71 and 64 tumors (overall accuracy of 0.87 and 0.78, respectively) and achieved Mantel-Haenszel χ2 values of 66 and 63 (P < 0.0001). Computed tomography allowed correct staging of 68 and 66 tumors (readers 1 and 2, overall accuracy of 0.83 and 0.80, respectively) with Mantel-Haenszel χ2 values of 54 and 54 for CT staging (P < 0.0001). No statistically significant difference between overall accuracy was found in the χ2 test (P > 0.15). Conclusion: Magnetic resonance imaging and multidetector-row CT with its multiplanar reconstruction capabilities achieve similar accuracy in tumor staging of renal cell carcinomas.

Relationship between blood flow, thrombus, and neointima in stents

PURPOSE To establish a relationship between flow, acute thrombus formation, and late intimal hyperplasia in arterial stents. MATERIALS AND METHODS To compare short-term stent patency in the canine femoral artery with normal flow to that in the opposite femoral artery with restricted flow, 24 dogs were subdivided in four groups: groups 1 (no intravenous heparin) and 2 (intravenous heparin) had unilateral flow restriction by surgically created stenosis, downstream of a Palmaz stent. Group 3 (no intravenous heparin) and 4 (intravenous heparin) had sham surgical exposure of the corresponding arterial segment, without flow restriction. Thrombocyte activity over the stent segment was evaluated for 3 hours after stent placement with nuclear scanning, after administration of indium-111-labeled platelets. To evaluate long-term stent patency in relationship to arterial flow, 14 additional dogs were subjected to long-term observation. Matched, symmetrically implanted femoral stents with normal and restricted flow, were explanted at 1, 12, and 24 weeks for histologic analysis and comparative measurement of neointimal thickness. Angiographic studies were performed before and after nuclear scanning in the short-term study group and before explant in the long-term animal group. RESULTS In the short-term, groups 2 and 4 showed neither increased platelet uptake nor angiographically demonstrable thrombus. Group 1 had increased platelet uptake and occlusive or subocclusive angiographic thrombus. Group 3 had increased platelet uptake and angiographic thrombus in one instance. In the long-term, stents with flow restriction had significantly greater neointimal formation in comparison with unrestricted stents. Histologic studies suggested that the stent neointima resulted from progressive replacement of stent thrombus. CONCLUSION Regardless of flow condition, intravenous heparinization is necessary to prevent thrombus formation in the stent lumen. Within the experimental parameters of this study, low flow and absent heparinization consistently lead to stent thrombosis. Stent implantation under low flow is associated with increased neointima formation. It is not known whether this is preventable by antithrombotic medication.

Morphologic and clinical results of the transjugular intrahepatic portosystemic stent-shunt (TIPSS)

The concept of transjugular intrahepatic portosystemic stent-assisted shunt (TIPSS) using the Palmaz iliac stent has been successfully accomplished in 18 of 24 patients representing a technical success rate of 75%. Fourteen were male, 4 female with a mean age of 60 years (range 34–84 years). According to classification of Child’s and Turcotte, 6 were in stage A, 6 in stage B, and 6 in stage C. Five patients were treated on an emergency basis because of massive active bleeding. In 10 patients the portosystemic tract was created between the middle hepatic vein and the right main stem of the portal vein in 8, and the left main stem in 2 patients. In 8 patients, the shunt was established between the right hepatic vein and the right main branch of the portal vein. The portosystemic gradient in 18 patients was 29.9±6 mm Hg and dropped to an average of 16.9±4 mm Hg after shunt establishment. Within the early postprocedural period of 30 days, 1 patient died of direct complications of the procedure. Because of catheter dislocation, embolization of the percutaneous transhepatic approach to the portal vein after successful shunt “creation” could not be done and was followed by intraabdominal exsanguination. One patient died of an ARDS after TIPSS. A third developed pulmonary infection. In 13 patients, because of hematomas at the puncture site of the transhepatic approach, only the transjugular approach was elected for establishing TIPSS. The mean portosystemic gradient in 18 patients prior to TIPSS was 29±6 mm Hg (range 19–41 mm Hg), dropped to an average of 16.9±4 mm Hg (range 7–21 mm Hg), and showed no significant change 6 months after TIPSS with a pressure of 16±1.8 mm Hg. The 1-year survival rate was 75% (8/12); the 2-year rate was 50% (3/6).

Acute Pancreatitis after Embolization of Liver Tumors: Frequency and Associated Risk Factors

Introduction: Acute pancreatitis (AP) is a rare complication after liver embolization (LE) of primary and secondary liver tumors (approximately 1.7%), but it has a significant morbidity and mortality potential if associated with other complications. It usually develops early within 24 h after the LE procedure. Study Purpose: To calculate the frequency of AP after LE in our institution and to analyze the factors involved in this procedure (anatomical features, embolization materials, cytostatic drugs, technical factors). Materials and Methods: 118 LE (bland embolization and transarterial chemoembolization) were performed in our institution. The study group included 59 patients who met the following inclusion criteria: one or more LE events, with complete pre- and post-interventional laboratory studies including: serum Ca2+, creatinine, blood urea nitrogen, glucose, lactate dehydrogenase, aminotransferases, alkaline phosphatase, amylase, lipase, C-reactive protein, hematocrit and leukocytes. The diagnosis of AP was established according to the criteria of the Atlanta system of classification. For the statistical analysis the association between two response variables (e.g. AP after embolization and risk factor during the embolization, AP after embolization and volume of embolic material) was evaluated using Pearson’s χ2 test and Fisher’s exact test. Results: The calculated frequency of AP after LE in our series was 15.2%. Amylase and lipase were elevated up to 8.7 and 20.1 times, respectively, 24 h after LE. We observed a statistically significantly lower incidence of AP in those patients who received 2 ml or less of embospheres compared with those with an embolization volume of >2 ml (Pearson’s χ2 = 4.5000, Pr = 0.034, Fisher’s exact test = 0.040). Although carboplatin was administered to 7 of 9 of the patients who developed AP after the embolization procedure, there was no statistical significance (Fisher’s exact test = 0.197) for carboplatin as an AP risk factor when compared with all the patients who received this drug (n = 107). Conclusion: Although AP after LE seems to have a multifactorial etiology, both the toxicity of the antineoplastic drugs (carboplatin-related toxicity) as well as direct ischemic mechanisms (non-target embolization, reflux mechanisms) may be the most important causes of the inflammatory pancreatic reaction after LE. We suggest that systematic measurement of serum pancreatic enzymes should be performed in cases of abdominal pain following selective LE and transarterial chemoembolization in order to confirm acute pancreatitis after embolization, which can clinically mimic a postembolization syndrome.

Comparison of spatial resolution in high-resolution multislice computed tomography and digital subtraction angiography using renal specimens

ObjectiveTo compare maximum spatial resolution in multislice computed tomography (MS-CT) and digital subtraction angiography (DSA) using an arterial tree model for canine kidney specimens. MethodsTwenty-three isolated fox terrier kidneys were catheterized with a 4F catheter and underwent contrast-enhanced MS-CT with a maximum spatial resolution of 0.23-mm isotropic voxel size in an early arterial phase. In addition, a digital subtraction angiogram was performed on all kidneys. The kidneys were segmented semiautomatically, and each parenchymal vessel that was identified in the kidney was marked. The maximum intensity projections of arterial vessels in the CT datasets were evaluated in a comparison with the DSA datasets. ResultsNo significant difference in vessel delineation and count was found at any level up to the fourth level of intrarenal branching. ConclusionMS-CT has the potential of replacing DSA in the diagnosis of intrarenal arteries.

Restoration of Liver Function and Portosystemic Pressure Gradient After TIPSS and Late TIPSS Occlusion

TIPSS (transjugular intrahepatic portosystemic shunt) may be indicated to control bleeding from esophageal and gastric varicose veins, to reduce ascites, and to treat patients with Budd-Chiari syndrome and veno-occlusive disease. Numerous measures to improve the safety and methodology of the procedure have helped to increase the technical and clinical success. Follow-up of TIPSS patients has revealed shunt stenosis to occur more often in patients with preserved liver function (Child A, Child B). In addition, the extent of liver cirrhosis is the main factor that determines prognosis in the long term. Little is known about the effects of TIPSS with respect to portosystemic hemodynamics. This report deals with a cirrhotic patient who stopped drinking 7 months prior to admission. He received TIPSS to control ascites and recurrent esophageal bleeding. Two years later remarkable hypertrophy of the left liver lobe and shunt occlusion was observed. The portosystemic pressure gradient dropped from 24 mmHg before TIPSS to 11 mmHg and remained stable after shunt occlusion. The Child’s B cirrhosis prior to TIPSS turned into Child’s A cirrhosis and remained stable during the follow-up period of 32 months. This indicates that liver function of TIPSS patients may recover due to hypertrophy of the remaining non-cirrhotic liver tissue. In addition the hepatic hemodynamics may return to normal. In conclusion, TIPSS cannot cure cirrhosis but its progress may be halted if the cause can be removed. This may result in a normal portosystemic gradient, leading consequently to shunt occlusion.

Vergleich digitaler Angiographie versus hochauflösender Computertomographie Ex vivo Evaluierung am Hundemodell

Dieser Beitrag beschaftigt sich mit dem quantitativen Vergleich zwischen digitaler Angiographie und hochauflosender Computertomographie. Bilder von 24 explantierten Hundenieren wurden durch beide Modalitaten akquiriert. Durch die Reduktion der CT-Aumahmen auf eine Maximum-Intensitats-Projektion konnten die Nierenbilder direkt miteinander verglichen werden. Dazu wurden von einem Experten mit Hilfe einer speziellen Software die Gefasverlaufe in den unterschiedlichen Bildern durch Polygonzuge nachgebildet. Die so entstandenen hierarchischen Graphen wurden mittels allgemeinem und Horton-Strahler Schema ausgewertet. Als Resultat konnte gefunden werden, dass die Subtraktionsangiographie durch das hochauflosende CT in seiner Auflosung nicht abgelost werden wird, aber die nachste Generation der CT-Gerate eine prazise dreidimensionale Operationsplanung erlaubt.