Zur Methodik und Genauigkeit der MR-Volumetrie der Orbita

OBJECTIVE

The aim of the present work was to establish a method for orbital volume calculation based on MR scanning data for the sake of better radiation hygiene.

MATERIALS AND METHODS

The orbital volumes of 35 ophthalmologically healthy children were calculated on the basis of MRI scans. After data transfer to a separate workstation, volumetric analysis was carried out by two independent radiologists using semi-automated software. The accuracy of the calculated values was compared with orbital volumes measured by anatomic preparations and given in studies by various authors.

RESULTS

Volume calculation was possible in all patients using MRI data. There is an acceptable agreement with the presented anatomic facts and the measured values of Bentheley. In the Wilcoxon test there was not a big difference between the courses of the values (p = 0.507).

CONCLUSION

Even though we can obtain a better image of the bizarre structure of the bony orbits with CT, MR-based volumetry of the orbit is a reliable method and is not burdened by radiation exposure. It can thus be an important condition for the planning and the controlling of modern therapeutic concepts in treating anophthalmos and microphthalmos.

Mycotic aneurysm rupture of the descending aorta

A 69-year-old diabetic male with salmonella bacteremia developed hypovolemic shock and swelling of the neck. A CT examination revealed massive mediastinal hemorrhage extending into the neck soft tissues caused by false aneurysm rupture of the descending thoracic aorta. Aortography showed continuous extravasation from a large leak at the medial side of the descending thoracic aorta. Although surgical intervention was immediately performed, the patient died 3 weeks later from multiple-organ failure. In this report, CT and angiographic findings of mycotic aneurysm rupture are presented and a review is given.

Transjugular intrahepatic portosystemic shunt (TIPS). Thrombogenicity in stents and its effect on shunt patency

PURPOSE

To compare the thrombogenicity and patency of the Palmaz stent and the Wallstent, and to evaluate the effect of periprocedural heparin therapy in cirrhotic patients with maintained coagulation capacity who receive a transjugular intrahepatic portosystemic shunt (TIPS).

MATERIAL AND METHODS

Twenty-four patients were randomized into 4 groups of 6 patients. Each received a Palmaz-stent or Wallstent TIPS with or without periprocedural heparin therapy. The groups receiving periprocedural heparin were given 24 U/kg b.w. just before stent placement, followed by 24 h therapeutic i.v. heparin. After 24 hours, all patients received i.v. heparin for 1 week followed by subcutaneous treatment with low-molecular-weight heparin (0.3 ml/day) for another 4 weeks. Stent thrombogenicity was determined scintigraphically after i.v. injection of 120-290 mBq of 99mTc-labeled platelets at the time of stent placement and expressed as the stent/heart ratio. Shunt patency was assessed by duplex sonography and confirmed radiologically.

RESULTS

The aggregation ratio was highest 90 min after stent implantation. Wallstents showed a significantly higher ratio than Palmaz stents. Heparin reduced the ratio in patients with a Wallstent (-41%) but had no effect on Palmaz stents. Patients with a Wallstent without heparin had a higher rate of early shunt insufficiency (66.6%) than the other patients (0-16.6%). Primary assisted long-term patency was similar in the 4 groups.

CONCLUSION

Wallstents were more thrombogenic than Palmaz stents and gave a significantly higher risk of early shunt insufficiency in cirrhotic patients with maintained coagulation capacity. Periprocedural heparin was effective in the prevention of shunt insufficiency and is therefore indicated in such patients.

Randomised trial of transjugular-intrahepatic-portosystemic shunt versus endoscopy plus propranolol for prevention of variceal rebleeding

BACKGROUND

The transjugular-intrahepatic-portosystemic shunt is a new interventional treatment for portal hypertension. The aim of our study was to compare the transjugular shunt with endoscopic treatment for the prophylaxis of recurrent variceal bleeding.

METHODS

Between March, 1993, and March, 1996, 126 patients with variceal bleeding were randomly assigned either transjugular shunt (n = 61) or endoscopic treatment (n = 65). Patients were followed up for a median of 14 (IQR 8-25) months and 13 (8-25) months, respectively. In 31 (51%) of the shunted patients, simultaneous transjugular-variceal embolisation was done at the time of shunt placement. Endoscopic treatment consisted of sclerotherapy and/or banding ligation and was combined with propranolol medication.

FINDINGS

Technical success was achieved in all patients assigned to the shunt group. During follow-up, the cumulative 1-year variceal rebleeding rates in the shunted and endoscopically treated patients were 15% and 41% and the 2-year rates were 21% and 52% (p = 0.001), respectively. In nine (12%) patients from the endoscopic group treatment failed and the patients received the transjugular-shunt treatment. A total of 19 bleeding episodes from any source occurred in 15 patients in the shunt group compared with 100 episodes in 33 patients in the endoscopic group. There was no difference in survival with estimated 1-year survival rates for shunted and endoscopically treated patients of 90% and 89%, and 2-year survival rates of 79% and 82%, respectively. The incidence of clinically significant hepatic encephalopathy after 1 year was higher in the shunt group (36% vs 18%, p = 0.011).

INTERPRETATION

These results suggest, that the transjugular shunt is more effective than endoscopic treatment in prevention of variceal rebleeding but has a considerable risk of hepatic encephalopathy. Survival is similar in the two groups.

[Recurrent bleeding from colonic varices in portal hypertension. The successful prevention of recurrence by the implantation of a transjugular intrahepatic stent-shunt (TIPS)]

HISTORY AND CLINICAL FINDINGS

Sclerotherapy was performed in a 52-year-old patient with alcoholic liver cirrhosis (Child-Pugh stage A) for recurrent bleeding from oesophageal varices. Half a year later he again was admitted to hospital because of recurrent passage of bloody stools. The cardiovascular status was stable; the liver was enlarged by 15 cm in the medioclavicular line.

INVESTIGATIONS

Endoscopy revealed several varices in the colon near the right flexure. One of the varices had an ulcer of 5 mm size. Duplex sonography revealed portal hypertension with cirrhosis of the liver and partial thrombosis of the main trunk of the portal vein without any sign of cavernous transformation.

TREATMENT AND COURSE

Because of the partial portal vein thrombosis it was decided to insert a transjugular intrahepatic portosystemic stent shunt. This obviated the thrombosis and lowered the portosystemic pressure gradient by 6.8%. With the shunt functioning well there were no further bleedings in the subsequent year.

CONCLUSION

The only slightly invasive TIPS implantation is an effective therapeutic procedure for bleeding from colon varices caused by portal hypertension.

Budd-Chiari syndrome: technical, hemodynamic, and clinical results of treatment with transjugular intrahepatic portosystemic shunt

PURPOSE

To evaluate use of the transjugular intrahepatic portosystemic shunt (TIPS) as a nonsurgical approach for the management of Budd-Chiari syndrome (BCS).

MATERIALS AND METHODS

Twelve patients with fulminant (n = 2), subacute (n = 5), or chronic (n = 5) BCS underwent TIPS placement. Hepatic venous obstruction was demonstrated at computed tomography and color duplex sonography. BCS was confirmed histologically in all patients. Hemodynamic parameters and clinical characteristics were assessed.

RESULTS

TIPS creation was successful in all patients. Treatment reduced the portal venous pressure gradient by 75% and resulted in a mean shunt flow of 2,300 mL/min +/- 650 (standard deviation). No serious procedure-related complications were observed. The two patients with fulminant BCS died of septicemia or progressive liver failure despite intervention. The other 10 patients showed clinical improvement with reduction or disappearance of ascites. During follow-up, shunt dysfunction occurred in five of 10 patients with recurrence of ascites requiring repeat intervention.

CONCLUSION

TIPS placement is safe and effective in patients with portal hypertension caused by subacute or chronic BCS.

[Septic portal vein thrombosis. Its successful therapy by local fibrinolysis and a transjugular portasystemic stent-shunt (TIPS)]

HISTORY AND FINDINGS

A 68-year-old man, without any preceding hepatic or abdominal disease, suddenly developed a severe septic illness with consumptive coagulopathy and upper abdominal pain. B-mode and duplex ultrasonography revealed fresh portal vein thrombosis. Despite extensive conservative measures there was no significant improvement after one week and further thrombus extension with threatened acute mesenteric vein occlusion.

TREATMENT AND COURSE

Local fibrinolysis with recombinant plasminogen activator and urokinase via percutaneous transjugular intrahepatic catheterization of the portal vein achieved almost complete dissolution of the thrombus within 3 days. Subsequently the portal vein catheter was changed into a transjugular portosystemic stent shunt (TIPS).

CONCLUSIONS

While local or systemic fibrinolysis has been practised in previously reported cases of acute portal vein thrombosis, the described use of TIPS introduces a new element. The shunt between hepatic and portal veins assures therapeutic access to the portal venous bed. It lowers portal vein pressure and can diminish the danger of recurrent thrombosis by raising portal flow. This minimally invasive procedure may be a nearly ideal treatment even in the course of portal vein thrombosis which has a high complication rate.

The transjugular intrahepatic portosystemic stent-shunt procedure for refractory ascites

BACKGROUND

Previous studies have suggested that the transjugular placement of an intrahepatic stent to establish a portosystemic shunt is an effective treatment of uncomplicated ascites accompanying variceal bleeding. We studied the stent shunt for use in patients with liver cirrhosis and ascites refractory to medical treatment.

METHODS

Fifty of 62 consecutive patients with cirrhosis and refractory ascites (18 with Child-Pugh class B liver disease and 32 with class C) were treated with the stent shunt--an expandable stent of metallic mesh placed between a major branch of the portal vein and one of the hepatic veins. Patients were followed for a mean (+/- SD) of 426 +/- 333 days. Those with advanced cancer, severe heart failure, or severe liver failure were excluded.

RESULTS

The stent shunt was successfully placed in all patients and reduced the pressure gradient between the portal vein and the inferior vena cava by an average of 63 percent. Thirty-seven patients (74 percent) had complete responses (total remission of ascites within three months), and nine patients (18 percent) had partial responses (ascites detected by ultrasound but with no need for paracentesis). Four patients did not respond, including two who died within two weeks of shunt placement. After the procedure, 25 patients had hepatic encephalopathy, as compared with 20 patients before the procedure; although encephalopathy improved in 3 patients, new encephalopathy developed in 8 patients. In the 28 of the 33 patients followed for more than six months who were evaluated, the mean serum creatinine concentration was 1.5 +/- 0.09 mg per deciliter (133 +/- 8 mumol per liter) before placement of the stent shunt, 1.5 +/- 1.6 mg per deciliter (133 +/- 141 mumol per liter) one week after the procedure, and 0.9 +/- 0.3 mg per deciliter (80 +/- 27 mumol per liter) after six months (P = 0.008 for the comparison of concentrations before and six months after the procedure). Renal function did not improve in the six patients with organic kidney disease. Procedure-related complications developed in 16 patients, including intraabdominal bleeding requiring blood transfusions in 2 patients. Thrombotic occlusion of the stent shunt occurred within two weeks in 5 patients, and later insufficiency of the shunt occurred in 16 patients, including 12 with recurrence of ascites after complete remission. During followup, an additional 29 patients died--10 of progressive liver disease and 19 of other causes. Survival for at least one year was associated with a patient's being under 60 years of age, having a serum bilirubin level before placement of the stent shunt of less than 1.3 mg per deciliter (22 mumol per liter), and having a complete response.

CONCLUSIONS

Our findings in an uncontrolled prospective study suggest that the transjugular intrahepatic porto-systemic stent-shunt procedure was an effective treatment for many patients with liver cirrhosis and refractory ascites, but mortality from underlying diseases was substantial.

[Percutaneous needle biopsy in skeletal metastases. Indications, technique, value and results]

Although modern imaging techniques have improved diagnostic specificity in osteolytic and osteoplastic lesions, histological examination is often still mandatory when primary bone tumors or skeletal metastases are concerned. We have developed a percutaneous puncture set, including sufficiently steady, but still fine biopsy needles (1.4-2 mm) and a slow rotating drill accessory. With this set, histological material can be obtained from almost anywhere in the skeleton with local anesthesia low complication risk, and low patient stress and discomfort. Together with the high accuracy of CT- or fluoroscopy-guided puncture (near 95%), this allows biopsies to be taken on an outpatient basis, with broad indications. Biopsy can be used early when making a diagnosis. Tedious searching for the primary tumor can thus be avoided with subsequent economic benefits.

The reducing stent: treatment for transjugular intrahepatic portosystemic shunt-induced refractory hepatic encephalopathy and liver failure

PURPOSE

To examine the efficacy of a stent device in reducing the diameter of transjugular intrahepatic portosystemic shunts (TIPS) in patients with progressive liver failure or with shunt-induced hepatic encephalopathy.

MATERIALS AND METHODS

Seven patients with TIPS (four with severe hepatic encephalopathy, three with progressive liver failure) underwent transjugular implantation of a stent designed to reduce the flow through the original TIPS channel.

RESULTS

Implantation of the reducing stent proceeded without complication. Duplex sonography showed that stent flow decreased by 41% +/- 18 (mean +/- standard deviation). The four patients with hepatic encephalopathy showed substantial improvement. Concentrations of plasma ammonium and serum bilirubin improved considerably. In contrast, functional impairment progressed in the three patients treated for liver failure. The patients soon died.

CONCLUSION

With the limited experience of treating these seven patients, the authors suggest that shunt-induced hepatic encephalopathy can be effectively treated with implantation of a reducing stent. Hepatic failure, however, is a deleterious complication that seems to be irreversible.

CT and MRI of Gorham syndrome

Gorham syndrome, also known as massive osteolysis or vanishing bone, is a rare disorder (135 cases reported) leading to extensive loss of bony matrix, replaced by proliferating thin-walled vascular channels. Three histologically proven cases of the disease are reported, including the clinical presentation and modern imaging features with CT (with 3D reconstruction) as well as T1- and T2-weighted MRI. Two cases in young women were located in the pelvis with extensive osteolysis reaching to the acetabulum. The third case in a 2-month-old boy is the youngest case ever reported and involved the humerus. The radiological appearance of the disease is discussed and the importance of the modern imaging methods debated.

Experimental use of a modified fibrin glue to induce site-directed angiogenesis from the aorta to the heart

From 10 cultures of manipulated Escherichia coli bacteria expressing the class I heparin-binding growth factor polypeptide alpha-endothelial cell growth factor, 11.2 +/- 0.7 mg alpha-endothelial cell growth factor was eluted by heparin-sepharose affinity chromatography. Analysis of molecular weight (17,000 kD) was done by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and purification of the growth factor was done by high-performance liquid chromatography. The harvested alpha-endothelial cell growth factor was proved by protein blotting. To assess the growth-promoting activity, we did an endothelial cell growth assay by comparing adult human endothelial cell control cultures, without adding growth factor to the culture medium, with adult human endothelial cell cultures with 0.02 to 20.0 ng/ml alpha-endothelial cell growth factor and 1.0 ng/ml heparin and with adult human endothelial cell cultures with alpha-endothelial cell growth factor but without heparin. Tritiated thymidine counts proved the significant growth-promoting activity of alpha-endothelial cell growth factor. In 10 experimental animals modified fibrin glue containing 1 microgram alpha-endothelial cell growth factor was implanted between the aorta and the myocardium of the left ventricle and results were compared with those in five control animals that received normal fibrin glue without growth factor. After 9 weeks of implantation, angiography and histologic investigation showed newly grown vascular structures between the aorta and the myocardium in all experimental animals, but none in the control animals. Our study proved the feasibility of initiating site-directed formation of new blood vessel structures to the heart by a modified fibrin glue implant containing angiogenic growth factor alpha-endothelial cell growth factor.

[Hemodynamics, liver function and clinical follow-up after TIPS]

In 126 patients with liver cirrhosis treated electively with transjugular intrahepatic portosystemic stent shunt (TIPS) to prevent variceal rebleeding, the portosystemic pressure gradient decreased by 60%. In spite of this incomplete effect the risk for variceal rebleeding was still under 20% after 2 years. Only 1 patient died of variceal rebleeding. Shunt insufficiency occurred in 50%, mainly during the first year, but shunt function was restored in nearly all cases by radiologic intervention, i.e., redilatation or implantation of an additional stent. During the follow-up of 16 +/- 9 months, 21 patients (17%) died, one-third of them from progressive liver failure aggravated in 4 cases by severe drinking. De novo hepatic encephalopathy was observed in 10%, especially in older patients and patients with impaired liver function before TIPS. In such patients it is recommended that the shunt be dilated to 0.8 cm at most, and the TIPS procedure can be combined with transjugular embolization of the varices. The advantages of TIPS over both endoscopic sclerotherapy and drug treatment must be clarified in randomized studies, which have already been initiated in several centers.

MR detection of quantitative and structural changes in human aortic aneurysms

Collagen is a major component of the extracellular matrix and a determinant of the elastic behavior of the human aorta. To investigate the changes found in aneurysmal degeneration, the authors studied the solid-state hydrogen-1 nuclear magnetic resonance line shape of collagen in aneurysms and normal human aortas. A three-component decomposition of the free induction decay was performed, with collagen characterized by a T2 of about 18 microseconds. The second moment of the collagen line shape was found to be increased in aneurysms (5.3 vs 4.8 G2), while, correspondingly, the T2 of collagen was lower in aneurysms (16.3 vs 17.7 microseconds). This corresponds to a modification of collagen structure and molecular motion. Collagen concentration was lower in nondiseased aortic walls (9.4% vs 7.3%). These results are discussed in reference to the contradictory conclusions in the current literature. The increase in collagen and the modification of its structure and molecular motion are explained by the need to resist an increasing tangential tension due to increased aortic diameter and diminished wall thickness in aneurysms and by intercalation or site binding in the helices or electric dipolar interactions in the less mobile side groups.

In vitro proton NMR study of collagen in human aortic wall

The authors relate the findings in the 1H solid state line shape (at 60 MHz) of human aortic walls (n = 12) in native state and after histologically controlled selective lysis of collagen and elastin. An analysis of the line shape shows a composite free induction decay (FID) consisting of a low amplitude (3-7%) fast decaying component (T2 approximately 20 microseconds) and a slow decaying one (T2 > 1 ms). The fast component is identified as the protons of the collagen macromolecules. The second moment computed from the experimental fast component of the FID is in agreement with published studies examining the motional characteristics of collagen by multinuclear NMR employing spin labeling. A theoretical second moment is computed for the collagen macromolecular backbone from the atomic positions in the superhelix. Comparison with the observed experimental values allows determination of the step angle (29 degrees) of the fast rotational motion of the collagen strands along their long axis.

Characterization of human aortic collagen's elasticity by nuclear magnetic resonance

The elasticity of the human aortic wall in longitudinal uniaxial elongation at high strain, known to be determined mostly from tissular collagen's behaviour, is studied and compared to the second moment of the 1H nuclear magnetic resonance (NMR) solid state line-shape, a proton nuclear magnetic resonance (at 60 MHz) characteristic for the molecular motion and the rigidity of the collagen macromolecular backbone. The 1H NMR signal of collagen is identified after selective histologically controlled chemical lysis. The computed second moment of the line-shape shows statistically significant correlation with the slope of the strain-stress curve of the aorta at high strain, thus proving the relationship between a macroscopic tissular elasticity parameter and a macromolecular rigidity characteristic of collagen, a major tissular component. In vivo extension of this technique (e.g., MRI) would allow us to gain information on the biomechanical state of the aorta, a naturally highly stressed and strained tissue.

[Digitization of conventional x-ray films]

The diagnostic value of a digitization system for analogue films based on a charge-coupled-device (CCD) scanner with adjustable resolution of 2.5 or 5 lp/mm was assessed. Some 110 skeletal radiographs, 50 contrast studies, including 25 of patients with Crohn's disease, and 70 abdominal plain films before and after successful lithotripsy for renal stones were digitized. Receiver operating characteristic (ROC) studies showed improved detection of cortical and trabecular defects with contrast-optimized digitized films. Edge enhancement algorithms yielded no additional information. Inflammatory lesions of Crohn's disease were detected equally well by conventional films and digitized images. A statistically significant improvement (p less than 0.05) in the recognition of disintegration after lithotripsy was found for the processed digitized images. On the basis of this initial investigation, the digitization system tested appears to be useful for diagnostic purposes, especially when contrast resolution plays an important part, as with stone fragmentation or cortical defects.

MR imaging of the pericardial cyst

Findings obtained with magnetic resonance (MR) imaging in four patients with pericardial cyst are reported. MR imaging allowed not only localization and diagnosis in all four cases but characterization of cystic content. MR imaging, including RARE (rapid acquisition with relaxation enhancement) MR hydrography, which shows only liquids with T2s greater than 500 msec, proved to be useful in characterizing the fluid content of a mediastinal lesion and monitoring follow-up. In one case, MR imaging allowed differentiation of a pericardial cyst from a suspected necrotic lymph node in a patient with colic carcinoma, with subsequent correction of staging and therapy. The authors conclude that MR imaging is the method of choice for diagnosis (especially in unusual locations) and monitoring of pericardial cysts and for differential diagnosis of malignant mediastinal cystic tumors that show a solid part.

[Diagnostic procedures in acute gastrointestinal hemorrhage]

In gastrointestinal bleeding, the diagnosis is predominantly made by endoscopy. However, if the bleeding site is in a part of the intestine that cannot be reached by endoscopy, than the diagnosis is based on radiological and scintigraphic methods. In the past 5 years 35 patients with such cases of gastrointestinal bleeding had angiography and/or scintigraphy (n = 15) in our department. Based on our retrospective study of those cases, we advocate a management protocol for such patients based on the hemodynamic presentation.

[Percutaneous interventions on the bile duct in obstructive jaundice. A meaningful or excruciating prolongation of life?]

The percutaneous transhepatic access to the bile duct opens a wide spectrum of diagnostic and therapeutic procedures. This means specific diagnosis and therapy of the obstructive jaundice even in patients in bad general conditions and therefore unfavourable prognosis. As in most cases curative therapy is no longer possible, survival time can be taken into consideration. There are no great problems concerning the performance of technical procedures. But it is the justifiability of the interventions that has to be reconsidered in each of the cases. The facts that the quality of life can be improved and the possibility to discharge the patient as soon as possible should be the guidelines in having the patients undergo these therapeutic procedures. The evaluation of our case material from 1985-1991 show that just in this respect the introduction of the endoprosthesis (thick calibrated endoprosthesis, stents) is a great progress, with a mean survival time between 8 and 10 months, and with normalization of laboratory values in 75-100%.

[Percutaneous transhepatic endoscopy and targetted tissue removal with an F-10.2 maneuverable thin cholangioscope]

Due to the flexibility and an external control mechanism of our thin calibrated cholangioscope (10.2 F) an inspection of the bile ducts via percutaneous transhepatic access is possible without too much discomfort for the patient. A 3.6 F working channel enables target-specific biopsies under optical control. It does not only enable histological diagnosis of the tumour itself but above all the exact definition of the proximal and distal tumour borders. This is a decisive criterion of operability and operation planning especially in tumours of the hepatic bifurcation. Expansion of the compressive lesion may be determined for palliative treatment. Percutaneous stone extraction by contact lithotripsy or with a Dormia basket is technically possible via the working channel under endoscopic view. An inspection of the peripheral branches of the same and the other liver lobe from one access only is made possible by easy maneuverability and flexibility of the endoscope.

[CT-guided biopsy. Comments on the puncture technique]

Computed tomography is an universally applied method of controlling diagnostic puncture of unrecognized processes in practically any region of the human body. The conditions required, the puncture technique, the various pathways and the types of needles used are discussed.

[Percutaneous diagnosis and therapy of the bile ducts and gallbladder. Feasibility and status]

Percutaneous transhepatic access to the bile duct has opened up new possibilities not only for diagnosis by means of cholangiography and cholangioscopy with endoscopically guided biopsy by small-bore equipment, but also for the treatment of benign and malignant obstructive jaundice. In malignant disease recanalization of the obstruction is possible by means of laser, intracavitary irritation, internal bile drainage in Klatskin tumors, large-diameter endoprostheses (e.g., a Y-shaped prosthesis) or metal stents. In benign disease, balloon dilatation of inflammatory stenoses, stone extractions from the bile duct or gallbladder by means of Dormia baskets, ultrasound or piezoelectric shockwave-contact lithotripsy and chemical litholysis are possible. Very often percutaneous access is a real alternative to surgical intervention.

Diagnostic imaging in metastatic lung disease

Chest radiographs, full lung tomography and computed tomography of the chest provide increasing sensitivity for evaluation of pulmonary metastases. Pulmonary nodules of 5-10 mm diameter are detectable with increasing frequency by use of high kilovoltage chest radiographs. Full lung linear tomography provides an overall accuracy of 72-97% in diagnosis of pulmonary nodules. Chest CT delineates pulmonary nodules as small as 3 mm within 10 mm slice sections. However, as sensitivity increases, specificity diminishes in identifying metastatic nodules. Sensitivity in CT is also reduced by false negative findings due to unequal respiratory cycles. Comparative radiologic-pathologic evaluation of nodule detection proved CT to be the most sensitive screening method for pulmonary metastases. Timing of follow-up studies for pulmonary nodule detection in cancer patients can be determined by tumor growth kinetics; 3-6 month intervals proved to be useful.

[Computed tomographic-guided fine-needle biopsy of the pancreas for histology determination]

Computed tomography-guided fine-needle biopsies of the pancreas were performed in 54 patients. In 46/54 biopsies, the material obtained permitted a histological diagnosis despite the small external needle diameter of only 0.95 mm. The only complication was due to laceration of an artery of the transverse mesocolon. The prevalence of malignant tumors was 67%. Adenocarcinoma was diagnosed in more than 80% of all biopsies; rare findings were malignant carcinoid or centroblastic lymphoma. Benign tumors included mucinous adenocystoma and serous microcystic adenoma. Within the group of patients where pathologic-anatomic evaluation was possible, the sensitivity of fine-needle biopsy for malignant tumors was 87% and the specificity 100%. A positive needle biopsy diagnosis for a malignant tumor reduces the number of exploratory laparotomies needed and is helpful in the planning of surgery.

[Wide-gauge bile duct endoprostheses with a port irrigation system. A new method of prolonging the drainage function]

The maintenance of adequate drainage by the bile ducts is crucial in all the endoscopic or percutaneous transhepatic procedures used today for the treatment of obstructive jaundice. We use wide-gauge polyurethane bile duct endoprostheses (F16; 5.3 mm - F20; 6.7 mm). Occlusion need not be expected to occur earlier than 4-6 months after placement. The implantation of a subcutaneous port system connected to the prosthesis by means of an F5 (1.6 mm) catheter allows not only X-ray examination of the function, but also lavage of the prosthesis and the biliary ducts. It is possible to add bile-dissolving substances, thus preventing crystallization of bile. In this way the patency of the prosthesis can be maintained for substantially longer. This also means a definite improvement in the quality of life.

[Limitations of computed tomographic differential diagnosis of focal liver changes]

Computed tomography of the liver is essential when there are discrepancies between ultrasonography, physical examination and laboratory findings. However, sometimes the referring clinicians overestimate the true accuracy of CT. Some of its major pitfalls include the limited spatial resolution and consequent false-negative results in the case of small focal lesions; further disadvantages are the inadequate contrast between a lesion and surrounding liver parenchyma, and limited specificity even in perfusion studies. When typical patterns in contrast and density of a cyst, hemangioma and focal nodular hyperplasia are present an accurate diagnosis is achieved. In atypical cases and in all other liver lesions further investigations will be necessary.

[Predictive value of magnetic resonance tomography in comparison with sonography and computed tomography in the diagnosis of focal liver lesions]

Ultrasonography and computed tomography are widely used for the diagnosis of focal lesions of the liver. However, the possibilities for tumor characterization and determination of potential malignancy are limited in many cases. Evaluation by magnetic resonance imaging shows a good correlation of relaxation time with the amount of stroma as a proportion of the total cell content of a lesion. This allows differentiation for a number of lesions. Thus, the combination of ultrasonography and magnetic resonance imaging could provide the ideal diagnostic procedure in many cases.

[Bone biopsy of uncertain bone lesions using a new biopsy cannula measuring 1.4 mm]

Bone biopsy for the clarification of ambiguous lesions has until now been the last resort in diagnostic procedures because obtaining the material for histological evaluation has involved very traumatizing methods (biopsy by surgical intervention, percutaneous biopsy with high-caliber needles). A new bone-biopsy apparatus has now been developed that is provided with a cannula not much larger than a fine needle (1,4 mm); it can be used to obtain histologically evaluable biopsy material from almost all regions of the skeletal system. As the procedure can be carried out under local anesthesia, there is no undue stress to the patient. The complication risk is no higher than when using conventional fine-needle biopsy. Despite the small diameter of this needle it is possible to obtain biopsy specimens not only of osteolytic but also of osteoplastic lesions. An electric motor (20 rotations/min) is the power source for apparatus. The value of bone biopsy in diagnostic procedures has increased considerably.

[A new Y-endoprosthesis for drainage of bile duct obstruction of the hepatic bifurcation]

Biliary decompression in cases of central tumorous biliary obstruction requires surgical or internal/external catheter bypass techniques. The development of a 14-F Y-shaped-polyurethane endoprosthesis stent provides the possibility to drain the left and right biliary system simultaneously. The endoprosthesis is placed by a combination of external transhepatic and endoscopic approach. The tip of the singular choledochal stent segment is placed within the choledochus or duodenum.

[Early postoperative control of internal thoracic artery-coronary artery anastomoses using intra-arterial DSA]

Early postoperative angiographic control is important for prognosis and medical therapy for patients undergoing coronary bypass surgery. Grafts from the internal mammary artery had been shown to be superior to venous bypasses for anastomoses to the left anterior descending coronary artery. Thus, the need for angiographic demonstration of graft patency and function is increasing. We report on the angiographic analyses of 73 patients after left internal mammary artery (LIMA) bypass surgery by filling of the graft via retrograde injection of contrast medium into the left brachial artery. In all cases the bypass, anastomosis and downstream vessel were clearly visualised. No complications or side effects were observed.

Significance of early angiographic follow-up after internal thoracic artery anastomosis in coronary surgery

The authors report about the radiological checking of the patency of the internal thoracic artery transplant in 75 patients with coronary artery disease, using intraarterial DSA in the early postoperative phase (between 6th and 8th postoperative day). The left or the right brachial artery was punctated and the contrast medium was injected at a dosage of 50 ml in counter-current. Only one angiogram series per patient was necessary to appraise the anastomosis and the perfusion of the bypass applied. In 5 patients a stenosis and in 4 patients an occlusion of the transplant could to be diagnosed. Early postoperative angiography enables quality control. In case of occlusion reoperation may be indicated.

[Initial clinical experiences with RARE-MR urography]

Potentials and limitations of a new, facultative non-tomographic Fast-Imaging sequence "RARE-MR-Urography" are presented. Its results in urological diseases are discussed on the basis of a pilot study of 35 patients. The images (4 s-32 s acquisition time) are extremely T2-weighted and display unbounded free water (urine). They reveal valuable information, not available with ultrasound or conventional radiology without application of contrast agents in the presence of urine retention. S/N problems reduce the accuracy of this method if the urinary tract contains only small amounts of urine.

[Preoperative tumor staging in rectal cancer--a prospective study]

A precise preoperative tumor staging is the prerequisite of distinct treatment planning and subtle operative regimen. Diagnostic contribution of the various examination techniques especially of imaging modalities were determined in a prospective study and correlated to intra- and postoperative findings. The TNM classification of malignant tumors of the UICC, both in its present valid and the modified form to be introduced in January 1987, formed the basis of our clinical diagnostic staging. Diagnostic accuracy in tumor staging increased significantly from 63.4% to 83.9%, if digital rectal examination, rectoscopy and barium enema were accompanied by computed tomography. Staging prediction solely concerning the surgically important differentiation between tumors "organ limited" (T1/T2 stage) and "organ extended" (T3/T4 stage) achieved an accuracy of 91/4 (97.0%).

[Preoperative staging of rectal cancer with computer tomography]

The correlation of the preoperative staging by CT with the postoperative staging was prospectively investigated in 112 patients with carcinoma of the rectum. The influence of CT on the choice of surgical treatment was also proven. The evaluation of the infiltration of perirectal tissue and especially of other organs is possible with CT. According to TNM classification the pre- and postoperative staging showed identical results by conventional diagnostic methods in T1 in 7/16, in T2 in 22/38, in T3 in 37/49 and in T4 in 5/9 patients. With the additional CT identical results were found in T1 in 7/14, in T2 in 25/31, in T3 in 49/53 and in T4 in 13/14 cases. Thus, the preoperative staging turned out to be correct with CT in 94/112 cases (83.9%). By conventional diagnostic methods identical results were found in 71/112 patients (63.4%). The infiltration of other organs was suspected preoperatively in 24 cases with CT and was found intraoperatively in 30/112 (accuracy 94.6%, sensitivity 88%, specificity 96%). Metastases of lymph nodes were suspected in the tomograms in 32/49 patients (65.3%). By the differentiated interpretation of the tumor growth with special regard to the "Grenzlamellen" of the rectum the CT gives important information for planning therapy.

[Echinococcus cysticus of the liver--sonographically a solid tumor]

In a patient with Hodgkin's disease, an intrahepatic echodense mass was diagnosed incidentally by ultrasonography. The sonographic pattern suggested a solid tumor. Despite negative or border-line serology, computed tomography established the diagnosis of Echinococcus cysticus by documentation of one "daughter" cyst; this diagnosis was confirmed by surgery. The criteria of Echinococcus cysticus in modern imaging methods like sonography and computed tomography are summarized and the diagnostic value of various procedures including diagnostic procedure in seronegative cases are discussed.

[The cutting biopsy cannula for histological diagnosis of abdominal and retroperitoneal masses. Sonographic or computed tomographic guided puncture?]

A new cutting biopsy needle has been used to obtain histologically useful material while causing the minimum of trauma. It permits biopsies of organs, but its small external diameter of 0.8 or 0.95 mm makes it possible to carry out transperitoneal puncture of the stomach, colon or liver and of the retroperitoneal space, using a ventral approach. Tissue samples were obtained in 96% of 63 patients. The risk of complications is no higher than for conventional needles used for cytology. The accuracy with which the material can be obtained is therefore the most important problem. The position of the area to be biopsied should determine whether the biopsy is to be aided by sonography or CT. Biopsies of organs can be appropriately carried out under ultrasound control, but processes in the pelvis and in retroperitoneal-paravertebral and extra-peritoneal positions are best biopsied under CT control.

[Acute pseudoobstruction of the colon (Ogilvie syndrome)]

Pseudo-obstruction of the colon was observed in six patients. The cardinal feature is acute distension of the large bowel without distal obstruction. Apart from few idiopathic cases, the syndrome usually is associated with postoperative, posttraumatic or metabolic disorders of extraintestinal origin. Without treatment, increasing distension leads to cecal perforation with a high mortality. Treatment is conservative initially. If decompression by colonoscopy fails, cecostomy or right hemicolectomy are mandatory. The pathophysiologic mechanism of acute colonic pseudoobstruction is unknown. Whether Ogilvie's syndrome is a genuine clinical entity or a complication of associated diseases is still on question.

[After-care problems and complications of percutaneous biliary drainage]

This is a follow-up study of 171 patients concerning the patients' care and complications following biliary drainage. Complications caused by puncture and drainage are considered separately. External biliary drainage resulted in 39%, internal in 26% with complications. The influence of advantages and side effects upon the indications of biliary drainage is discussed. Prognosis concerning the survival rate depends on the underlying pathology: In obstructive jaundice caused by metastases the patients only survived two months while the mean survival rate in carcinoma of the biliary ducts is 18 months.

[Transvenous atrial septal defect occlusion in an animal experiment]

Preliminary results concerning the occlusion of experimental atrial-septal defects (ASDII) of the secundum type are reported. An occlusion element was inserted transvenously and its passage across the atrial-septal defect was controlled by open-heart surgery in dogs. Subsequently, the defect was occluded using a single-piece element. In all 5 surgical experiments the occlusion was possible without dislocation or embolism of the element during an atrial stimulation of the heart for more than 1 hour. In additional experiments without open-heart surgery, atrial-septal defects were produced in 7 dogs by transseptal punction and perforation under X-ray control. The atrial-septal defects could be closed for a short time in 2 dogs. In 1 of the 2 dogs the element embolized into the right pulmonary artery, and in the other into the abdominal aorta. Transvenous occlusion of experimental atrial-septal defects is possible, but more experimental work is necessary with respect to the technical problems.