Effects of altering infusion parameters on intimal hyperplasia following local catheter-based delivery into the rabbit iliac artery

BACKGROUND

Efficient local gene or drug therapy requires optimized application modalities to avoid vessel damage, which might lead to increased neointimal hyperplasia. Aim of the study was to evaluate different application parameters for local delivery using the channeled balloon catheter in order to minimize vessel trauma induced by local application.

METHODS AND RESULTS

Sixty cholesterol fed rabbits were randomly enrolled into twelve groups of different local application parameters: group I, application pressure 2atm/application volume 1ml physiologic saline; group II, 2atm/2ml; group III, 2atm/5ml; group IV, 4atm/1ml; group V, 4atm/2ml; group VI, 4atm/5ml. The other six groups received Ringer's solution instead of saline. Administration of the solution was randomly performed in one iliac artery using the channeled balloon catheter with simultaneous balloon angioplasty (8atm). The contralateral iliac artery served as a control and was treated with balloon angioplasty only. Four weeks after local therapy, calibrated angiography was performed; the animals were sacrificed, vessel segments were excised and quantitative morphometric measurements were obtained. In none of the animals acute complications, e.g. dissection, thrombosis or perforation of the vessel, was noted. Up to an application pressure of 4atm and an application volume of 5ml, no significant neointima formation was seen compared to arteries which underwent angioplasty only. Additionally, no significant differences between saline and Ringer's solution were detected. In a multivariate analysis, neither application pressure nor volume were found to have a statistically significant influence on the amount of neointimal hyperplasia.

CONCLUSIONS

Local application of "drugs" using the channeled balloon catheter is safe and feasible without significant induction of neointimal hyperplasia compared to angioplasty, if an application volume of 5ml and a pressure of 4atm is not exceeded.

Analysis of Mice Tumor Models Using Dynamic MRI Data and a Dedicated Software Platform*

PURPOSE

To implement a software platform (DynaVision) dedicated to analyze data from functional imaging of tumors with different mathematical approaches, and to test the software platform in pancreatic carcinoma xenografts in mice with severe combined immunodeficiency disease (SCID).

MATERIALS AND METHODS

A software program was developed for extraction and visualization of tissue perfusion parameters from dynamic contrast-enhanced images. This includes regional parameter calculation from enhancement curves, parametric images (e. g., blood flow), animation, 3D visualization, two-compartment modeling, a mode for comparing different datasets (e. g., therapy monitoring), and motion correction. We analyzed xenograft tumors from two pancreatic carcinoma cell lines (BxPC3 and ASPC1) implanted in 14 SCID mice after injection of Gd-DTPA into the tail vein. These data were correlated with histopathological findings.

RESULTS

Image analysis was completed in approximately 15 minutes per data set. The possibility of drawing and editing ROIs within the whole data set makes it easy to obtain quantitative data from the intensity-time curves. In one animal, motion artifacts reduced the image quality to a greater extent but data analysis was still possible after motion correction. Dynamic MRI of mice tumor models revealed a highly heterogeneous distribution of the contrast-enhancement curves and derived parameters, which correlated with differences in histopathology. ASPC1 tumors showed a more hypervascular type of curves with faster and higher signal enhancement rate (wash-in) and a faster signal decrease (wash-out). BXPC3 tumors showed a more hypovascular type with slower wash-in and wash-out. This correlated with the biological properties of the tumors.

CONCLUSION

With the described software, it was possible to analyze tissue perfusion parameters in small xenograft tumor models in mice. Our data correlated with histopathological data, and the qualitative and quantitative perfusion parameters could distinguish two tumor entities with different growth characteristics.

Virtuelle Organisation im digitalen Zeitalter der Radiologie - Prinzip und Lösung für die radiologische Forschung?∗

The research project "VICORA - Virtual Institute for Computer-Assisted Radiology", funded by the German Federal Ministry of Education and Research, was initiated in the year 2000. Its virtual organization brings together physical science, engineering, information technology, clinical radiology and the medical technology industry. In the German radiology research domain VICORA serves as a model for interdisciplinary collaboration for the changing radiology paradigm illustrated by a "radiologycube". The project does not only aim at scientific goals but also considers the infrastructure, components and human resource management within a virtual organization. The common rapid prototyping platform ILAB 4 ensures user-friendly and time-efficient software that assists with the routine radiology work-flow including full DICOM functionality. By offering a new work environment and collaborative culture based on telematics and knowledge exchange in radiology research, VICORA overcomes limitations of traditional research organization.

In vitro MR imaging of regulated gene expression

PURPOSE

To design and evaluate a construct that allows regulated expression of the magnetic resonance (MR) imaging reporter gene human tyrosinase under control of the tetracycline response element.

MATERIALS AND METHODS

A breast cancer cell line (MCF-7) was transfected with a plasmid that codes for the tetracycline-controlled transactivator and a new construct. In this construct, the reporter gene human tyrosinase is under control of the tetracycline response element, thus allowing suppression of gene expression by adding doxycycline (tetracycline switched off). A reverse transcription polymerase chain reaction was conducted to evaluate gene expression. Additionally, immunohistochemical investigation of tyrosinase and melanin staining was undertaken to analyze the presence of these molecules. After culture in an iron- and holotransferrin-enriched medium, cells were imaged in a 1.0-T clinical MR imager by using a surface coil and T1-weighted spin-echo and gradient-echo sequences.

RESULTS

Two stable transfected cell clones were established. Cells cultured with doxycycline showed no background expression of the human tyrosinase gene, whereas withdrawal of doxycycline resulted in detectable tyrosinase messenger RNA expression. Gene expression results in a detectable tyrosinase protein level and melanin content. Increased signal intensity on T1-weighted MR images in cells that expressed the reporter gene was observed in comparison to genetically identical cells with the reporter gene switched off.

CONCLUSION

Our construct enables MR imaging of regulated tyrosinase gene expression in vitro.

[Treatment of malignant biliary occlusion by means of transhepatic percutaneous biliary drainage with insertion of metal stents--results of an 8-year follow-up and analysis of the prognostic parameters]

PURPOSE

To analyze outcome and predictive factors for patient survival and patency rates of unresectable malignant biliary obstruction treated with percutaneous transhepatic insertion of metal stents.

MATERIALS AND METHODS

This is a retroslective analysis of 130 patients treated in one interventional radiological center with data collected from patient records and by telephone interviews. The procedure-related data had been prospectively documented in a computer data base. The Kaplan-Meier analysis was performed for univariate and multivariate comparison of survival and patency rates with the log-rank test used for different tumor types. Predictive factors for survival and 30-day mortality were analyzed by a stepwise logistic regression.

RESULTS

Underlying causes of malignant biliary obstructions were cholangiocarcinoma in 50, pancreatic carcinoma in 29, liver metastases in 27, gallbladder carcinoma in 20, and other tumors in 4 patients. The technical success rate was 99 %, the complication rate 27 % and the 30-day mortality 11 %. Primary patency rates (406 days with a median of 207 days) did not differ significantly for different tumor types. The survival rates were significantly (p = 0.03 by log-rank test) better for patients with cholangiocarcinoma than for patients with pancreatic carcinoma and liver metastases. Multiple regression analysis revealed no predictive factor for patient survival and 30-day mortality.

CONCLUSION

Percutaneous transhepatic insertion of metal biliary endoprostheses offers a good initial and long-term relief of jaundice caused by malignant biliary obstruction. Although survival rates for patients with cholangiocarcinoma are better than for other causes of malignant biliary obstruction, a clear predictive factor is lacking for patients undergoing palliative biliary stent insertion.

Magnetic resonance urography in pediatric urology

OBJECTIVE

To evaluate the efficiency of magnetic resonance urography (MRU) in pediatric urology.

MATERIAL AND METHODS

We report retrospectively on 12 children who underwent MRU between January 1999 and November 2001. MRU was performed to accurately evaluate the entire urinary tract because of megaureter, ectopic ureter, vesicoureteral reflux, Y-inverted duplication and hydronephrosis because of pyeloureteral stenosis. T1- and T2-weighted images were obtained in the coronal, sagittal and axial planes. The mean age of the children (8 females, 4 males) investigated was 36 months (range 2-140 months).

RESULTS

An accurate anatomical picture of the entire urinary tract could be obtained in all children. The obstructive nature of megaureter could be differentiated. The distal orifice of ectopic ureter could be identified in the vagina. Vesicoureteral reflux into the blind-ending ureteral bud of a duplicated system was accurately identified. Hydronephrosis was demonstrated to be the result of pyeloureteral stenosis. The location of stenoses was easily identified in the sagittal and coronal planes.

CONCLUSIONS

MRU is an excellent imaging modality for accurately depicting the urinary tract. MRU is superior to conventional intravenous urography because it does not use ionizing radiation, the gadolinium contrast medium used is not nephrotoxic and the imaging quality is excellent, reproducible and not interfered with by gas superposition. Considering the high costs and diagnostic benefit of MRU compared to intravenous urography, MRU should be performed in patients with impaired renal function, in those with an allergy to contrast medium and if anatomic relationships are not clear prior to reconstructive surgery.

1-molar gadobutrol as a contrast agent for computed tomography: results from a comparative porcine study

RATIONALE AND OBJECTIVES

To evaluate prospectively the efficacy of gadobutrol as contrast agent for computed tomography (CT) compared with iodinated contrast media in a porcine animal model.

METHODS

In 8 domestic pigs (35 +/- 4 kg body weight [BW]), continuous spiral CTs of the chest and abdomen were performed using either 2 mmol/kg BW Gadovist 1.0 (1 mol/L gadobutrol) intravenously or Ultravist (300 mg I/mL iopromide) (slice 5 mm, table feed 7.5 mm, reconstruction increment 5 mm). One week later, the same animals were examined using the same protocol with the other contrast agent. In 2 additional animals, serial CTs were performed at the same level using gadobutrol or iopromide on day 1 and the alternate agent on day 8 inches order to determine contrast media kinetics, peak enhancement, and time enhancement-product in important vascular regions and parenchymal organs (abdominal aorta, inferior vena cava, liver, and renal parenchyma). Peak enhancement (net increase compared with nonenhanced baseline values) was measured in Hounsfield units (HU) in defined regions of interest.

RESULTS

In vivo, the mean peak enhancement 5, 15, 30, and 120 seconds in the abdominal aorta after injection of 2 mL/kg BW gadobutrol and iopromide was 200 +/- 11, 224 +/- 10, 261 +/- 13, and 95 +/- 9 HU versus 232 +/- 10, 298 +/- 10, 152 +/- 11, and 123 +/- 10 HU, respectively. Differences in enhancement of vascular structures was statistically significant (P < 0.05) in carotid arteries (235 +/- 20 HU for gadobutrol and 264 +/- 19 HU for iopromide) and the aortic arch (261 +/- 14 HU for gadobutrol and 279 HU +/- 13 HU for iopromide). No statistical significance was seen in all other measured vascular structures and parenchymal organs.

CONCLUSION

Contrast-enhanced CT with 1 mol/L gadobutrol in a dose of 2 mmol/kg BW resulted in an excellent vascular and parenchymal enhancement in most vascular regions and parenchymal organs similar to an equivalent volume of 300 mg/mL iodinated contrast media.

[What effect does the hydroxyapatite coating have in cementless knee arthroplasty?]

The goal of this study was to compare the migration of noncemented diffusion sintered titanium fibermesh-coated tibial components with (HA group) and without (non-HA group) additional hydroxyapatite coating. For this purpose digital radiostereometry (DIRSA) was used to compare the migration after 2 and 9 years for the two groups. After 2 years the mean maximum subsidence of the HA-coated components (0.24+/-0.18 mm) was about one-half of the mean maximum subsidence of the non-HA-coated group (0.55+/-0.55 mm). After 9 years the maximum subsidence of the HA-coated components was still smaller, but not as pronounced as before. The same trend was also found for the endpoint maximum total point motion (MTPM). After 2 years the mean MTPM of the HA-coated components was 0.66+/-0.38 mm and of the non-HA group 0.73+/-0.50 mm. After 9 years the mean MTPM for the HA-coated components was 0.54+/-0.15 mm and for the non-HA-coated components 0.74+/-0.20 mm. None of the HA-coated tibial components but one of the non-HA group had to be revised and exchanged due to aseptic loosening.

Comparative study of MR sialography and digital subtraction sialography for benign salivary gland disorders

BACKGROUND AND PURPOSE

MR sialography has become an alternative imaging technique for ductal salivary gland diseases. We compared the diagnostic accuracies of MR sialography and digital subtraction sialography in patients with successful completion of both examinations and benign salivary gland disorders.

METHODS

In a prospective study, we attempted to examine salivary glands in 80 patients with clinically suspected diagnoses of sialadenitis and/or sialolithiasis. Each patient underwent digital subtraction sialography and MR sialography. MR sialography was obtained with a T2-weighted single-shot turbo spin-echo sequence (TR/TE 2800/1100 msec, acquisition time 7 seconds), with use of a quadrature head coil. Final diagnoses were confirmed by clinical follow-up and results of biopsy (n = 9) or surgery (n = 19).

RESULTS

Failure rate was 5% (four of 80) for MR sialography and 14% (11 of 80) for digital subtraction sialography. Eighty-one salivary glands (48 parotid, 33 submandibular) in 65 patients were successfully visualized with both modalities. MR sialography depicted the main ductal system and first- and second-order branches, whereas digital subtraction sialography was able to depict third-order branches. Sensitivity and specificity to diagnose chronic sialadenitis were 70% and 98% with MR and 96% and 100% with digital subtraction sialography. MR sialography enabled diagnosis of sialolithiasis with a sensitivity of 80% and a specificity of 98% versus 90% and 98% for each with digital subtraction sialography.

CONCLUSION

MR sialography with a heavily T2-weighted sequence is highly successful in the noninvasive visualization of the ductal system of major salivary glands. It is useful for diagnosing sialolithiasis and sialadenitis. Digital subtraction sialography, an invasive technique, had a substantial procedural failure rate, particularly for the submandibular duct. However, because of its higher spatial resolution, successfully completed digital subtraction sialography achieved superior diagnostic information compared with that of MR sialography.

[Secretin-stimulated MR cholangiopancreatography (MRCP): visualization of the normal pancreatic duct in comparison with ERCP]

PURPOSE

To determine whether the application of secretin improves the depiction of the normal pancreatic duct and to document the time course of any possible improved visualisation.

PATIENTS AND METHODS

Twenty-eight patients with a normal pancreatic ductal system, proved by ERCP, were prospectively enrolled in our study. MRCP was carried out in a 1.0 Tesla unit using a thick slab single-shot turbo-echo sequence (TR: infinity, TE: 1100 ms, FA: 150 degrees, slab thickness: 65 mm). Following acquisition of a non-enhanced image, 1 clinical unit/kg bodyweight of secretin was injected intravenously. During the subsequent ten minutes the MR measurement was repeated every 30 seconds. The images were independently evaluated by two investigators.

RESULTS

The improvement in quality after administration of secretin was statistically significant for both investigators (p < 0.05), but no significant difference was found between both investigators concerning the quality of the images (p = 0.49). Prior to the secretin application, the entire ductal system only be evaluated in ten cases (35.7 %) by both investigators, afterwards in 26 cases (92.9 %). Improvement was achieved after a mean time of 1.5 minutes and lasted until the ninth minute.

CONCLUSION

Intravenous application of secretin improves image quality of MRCP also in patients with no pancreatic pathology. Improvement begins after 1.5 minutes and lasts for about seven minutes.

Superselective embolization with coils in high-flow priapism

Priapism can be divided into "low-flow" veno-occlusive priapism and, especially in children, rare "high-flow" arterial priapism. We report a 5-year-old boy who developed arterial priapism after blunt perineal trauma that was successfully treated by superselective embolization with microcoils.

["Activity based costing" in radiology]

BACKGROUND

The introduction of diagnosis related groups for reimbursement of hospital services in Germany (g-drg) demands for a reconsideration of utilization of radiological products and costs related to them.

METHODS

Traditional cost accounting as approach to internal, department related budgets are compared with the accounting method of activity based costing (ABC). The steps, which are necessary to implement ABC in radiology are developed.

CONCLUSIONS

The introduction of a process-oriented cost analysis is feasible for radiology departments. ABC plays a central role in the set-up of decentralized controlling functions within this institutions. The implementation seems to be a strategic challenge for department managers to get more appropriate data for adequate enterprise decisions. The necessary steps of process analysis can be used for other purposes (Certification, digital migration) as well.

X-ray digital subtraction angiography with 1 mol/L gadobutrol: results from a comparative porcine study With iodinated contrast agents

RATIONALE AND OBJECTIVES

To evaluate prospectively diagnostic accuracy of 1 mol/L gadobutrol as a contrast agent for intraarterial x-ray digital subtraction angiography (DSA) in comparison to iodinated, nonionic contrast media and 0.5 mol/L gadolinium-DTPA.

METHODS

Flush arteriograms (ascending, descending, abdominal aorta, iliac, and femoral arteries) and selective angiograms (carotid, renal, and visceral arteries) were obtained from bilateral femoral arterial access (5 F sheaths) in 10 domestic pigs (70 kg body weight). Digital subtracted angiograms were obtained during injection of undiluted 1 mol/L gadobutrol, 300 mg I/mL iopromide, or 0.5 mol/L gadopentetate. Injection parameters (volume and velocity) were similar for all three contrast agents. In paired arteries, two different contrast media were used during the same angiographic run. Diagnostic quality and accuracy of the angiograms were evaluated on a three-step scale by three independent blinded investigators.

RESULTS

Sufficient nonselective angiographic images were obtained in 90% of cases using iodinated contrast material. Gadobutrol achieved sufficient nonselective angiograms in 64%. Selective angiograms were sufficient in 98% using iodinated contrast material, 90% using 1 mol/L Gadobutrol and 48% using 0.5 mol/L Gd-DTPA. Adverse reactions to any of the used contrast agents were not noted.

CONCLUSION

One mol/L Gadobutrol solution allows x-ray digital subtraction angiography with a diagnostic accuracy equivalent to 300 mg/mL iodinated contrast media, if selective injections are performed. Flush aortograms are of inferior image quality to iodinated contrast material.

Magnetic resonance hydrometry: non-invasive quantification of the exocrine pancreatic function

AIMS

To show the ability of magnetic resonance hydrometry (MRH) to quantify the pancreatic secretion after secretin stimulation in order to distinguish between physiological excretion and reduced output in chronic pancreatitis.

METHODS

MRH images were acquired in a 1.0-T-clinical scanner using a body-array coil and a heavily T2-weighted standard single-shot TSE sequence. Thirty-one patients (14 male/17 female) who routinely underwent ERCP for suspected choledocholithiasis (n = 22), recurring abdominal pain (n = 1), icterus (n = 6 and suspected pancreatitis (n = 2) were included. During the investigation 1 CU/kg BW secretin were administered intravenously. Secreted volume of fluid, start of secretion, achievement of a plateau of secretion and a combined score of these parameters (MRH score) were assessed and evaluated. Sensitivity and specificity were calculated for these parameters.

RESULTS

27 patients had no pancreatic pathology, and four suffered from chronic pancreatitis. Patients without pancreatic disorders produced a mean pancreatic fluid volume of 183 plus minus 86 mL, whereas patients with chronic pancreatitis secreted 61 +/- 39 mL. Secretion started after a mean time of 95 +/- 94 seconds (no pancreatic impairment) and 62 +/- 13 seconds (chronic pancreatitis). The MRH score achieved a high accuracy in the detection of chronic pancreatitis.

CONCLUSIONS

Our study demonstrated the feasibility of measuring pancreatic output by MRH after stimulation with secretin. Moreover, a distinction between normal secretion and patients with chronic pancreatitis is possible.

Acute colonic diverticulitis: visualization in magnetic resonance imaging

The incidence of acute colonic diverticulitis (ACD) is increasing. To allow rational therapeutic decisions to be made, a timely diagnosis is required. The feasibility of "on-admission-MRI" to establish the diagnosis has not yet been studied. Therefore, a prospective observational study was carried out in 20 patients with an established diagnosis of ACD. The diagnostic criteria for the MRI diagnosis of ACD were the demonstration of at least one diverticulum, pericolic exudation, and edema of the colonic wall. MRI was diagnostic in all but one patient. It is concluded that MRI has considerable diagnostic potential in ACD and should be formally evaluated.

Multiplanar reconstructions and three-dimensional imaging (computed rotational osteography) of complex fractures by using a C-arm system: initial results

With use of a calibrated angiographic C-arm system and a postprocessing workstation, the authors acquired volume data sets from two-dimensional digital projection images obtained during a C-arm rotation around the patient axis. Multiplanar reconstruction and three-dimensional images of complex fractures were reconstructed and compared with spiral computed tomographic studies in a cadaveric pig study and in eight patients. Computed rotational osteography provided high-resolution multiplanar reconstruction and three-dimensional images of complex fractures.

Vascular response to gadolinium-containing contrast media in an ex vivo rabbit arterial model

RATIONALE AND OBJECTIVES

To assess the influence of gadolinium-containing magnetic resonance contrast agents on contractility of the arterial vessel wall.

METHODS

Bilateral segments of rabbit carotid arteries were mounted in flow chambers, surrounded by aerated (95% O2, 5% CO2) Krebs' solution, and perfused at a constant rate by separated and aerated Krebs' solution. Therefore, changes in pressure of the circulating Krebs' solution indicated alterations of vessel wall contractility. Viability of the artery was tested by 124 mmol/L KCl, 3 x 10-5 mol/L phenylephrine, and 10-5 mol/L acetylcholine. After a washout phase, gadopentate (n = 10) or gadoteridol (n = 10) was added to the perfusate of one carotid artery in increments of 0.1, 0.3, and 0.6 mmol/L. Concentrations up to 0.9 mmol/L and 1.2 mmol/L were tested, respectively. The contralateral artery served as a control. To assess potential relaxing effects of the media, vessels were brought into a contracted status with 3 x 10-5 mol/L phenylephrine and then received gadolinium chelates.

RESULTS

Potassium chloride and phenylephrine increased and acetylcholine decreased the pressure, indicating vasoconstriction and vasodilatation, respectively. After gadopentate and gadoteridol infusion, no statistically significant pressure changes could be detected, ruling out any vasoconstrictor or vasodilator effect.

CONCLUSIONS

Gadopentetate and gadoteridol in doses of up to 1.2 mmol/L did not alter vessel wall tone. The impact of contrast media on blood pressure, as has been shown in some clinical trials, probably is not due to direct changes in arterial wall tone.

Measurement of torsion angles of long finger bones using computed tomography

OBJECTIVE

Rotational dislocation at the fracture site is a complication of long finger bone fractures of the metacarpals and phalanges. To evaluate such deformities, we performed CT of the articular surfaces of these bones to demonstrate the torsion angles.

DESIGN

We evaluated 10 pairs of cadaver hands. These were placed flat, with the bones of interest perpendicular to the gantry to acquire axial images. The torsion of the long bone axes was defined as the angle between a tangent positioned parallel to the proximal articular surface and a tangent parallel to the distal articular surface of individual bones.

RESULTS

The maximum difference between repeated measurements was 4 degrees. Intraobserver differences measured between right and left hands are less than 3 degrees.

CONCLUSION

Side differences in torsion angles exceeding 3 degrees are strongly suspicious of a malrotation after fracture. These measurements might help to plan derotational osteotomy and assess the results of therapy.

Kinetic evaluation of an i.v. bolus of MR contrast media

Currently, it is assumed that the pharmacokinetic properties of the first minutes of an I.V. MR contrast media bolus are similar to those of an i.v. iodinated contrast media bolus used in CT. Correct timing of an MRA examination is crucial for obtaining sufficient arterial contrast. This study sought to evaluate the temporal change of arterial signal intensity within 150 s after i.v. bolus injection of Gd-DTPA. Thirty consecutive patients (14 women/16 men; mean age: 51 +/- 11 years) were prospectively examined with a 1.0 Tesla clinical scanner. A single axial slice was acquired in 1.25 sec with manufacturer provided gradient echo sequence through the aorta at the level of the renal arteries. Investigation was started simultaneously to the application of contrast media (0.1 mmol/kg bodyweight Gd-DTPA at three different rates 2 mL/sec, 3 mL/sec and 4 mL/sec) and repeated for 2.5 min. An additional echo Doppler examination excluded patients with any cardiac disorders. Maximum signal (1300% increase compared to the basic value) in the aorta was achieved 20 +/- 6 sec after start of bolus injection. Then a plateau phase was maintained for the remaining investigation time (2.5 min). No significant difference was shown for different injection rates. After a bolus injection of Gd-DTPA the arterial contrast remains on a high level for at least 2 min. However, correct timing of the bolus arrival is still crucial to discriminate arteries and veins. An injection rate between 2 mL/sec and 4 mL/sec has no influence on early contrast media dynamics.

[MRI or arthroscopy in the diagnosis of scapholunate ligament tears in fractures of the distal radius?]

In a prospective study, 45 patients with fractures of the distal radius and radiologically suspected tears of the scapholunate interosseous ligament were examined. Magnetic resonance imaging was performed prior to wrist arthroscopy. The latter examination gave the definite diagnosis. MRI was performed in conventional technique (without contrast medium) in 25 cases and after additional intravenous injection of contrast medium in the remaining 20 patients. The images were obtained with a 1.0-T clinical imager using a T(2)-weighted turbo spin echo sequence (slice 3 mm, transversal) and a FLASH 2D sequence (slice 2 mm, oblique/coronal). Three independent observers assessed the MRI scans before arthroscopy was performed. The correct diagnosis was made by MRI in 76 %. Overall sensitivity and specificity came to 71 % and 86 %, respectively. The use of intravenously applied contrast medium did not improve MRI accuracy. In conclusion, MRI is not recommended for the diagnosis of scapholunate ligament tears. Presumably, the results of MRI could be improved by a more sophisticated technique.

Comparative Trial of Local Pharmacotherapy withl-Arginine, r-Hirudin, and Molsidomine to Reduce Restenosis after Balloon Angioplasty of Stenotic Rabbit Iliac Arteries

PURPOSE

To determine if local application of L-arginine, r-hirudin, or molsidomine significantly reduces restenosis after balloon angioplasty in stenotic rabbit iliac arteries.

MATERIALS AND METHODS

Thirty-one male cholesterol-fed New Zealand white rabbits underwent balloon dilation of both common iliac arteries to induce arterial stenosis. Four weeks later, one stenotic iliac artery was simultaneously dilated and received local application of L-arginine (210 mg/mL, n = 7), r-hirudin (0.5 mg/mL, n = 8), or molsidomine (0.2 mg/mL, n = 8) with a channeled balloon catheter. On the contralateral side, 0.9% saline was injected as a control. In eight sham animals, saline was applied to one iliac artery and balloon dilation to only the contralateral artery. Six weeks after local treatment, vessels were harvested, and computerized morphometric and immunohistologic analyses were performed.

RESULTS

Application of drugs resulted in a significant reduction of neointimal area as follows: 53% with L-arginine (1.01 mm(2) vs. 2.17 mm(2), P <.05), 43% with molsidomine (1.04 mm(2) vs. 1.89 mm(2), P <.05), and 20% with r-hirudin (1.79 mm(2) vs. 2.24 mm(2), P <.05). Infusion of saline led to a significant increase (50%, 1.21 mm(2) vs. 1.93 mm(2), P <.05) in neointimal area compared with balloon dilation alone. Immunohistologic findings showed a significant reduction of macrophages (5.0% vs. 10.2%, P <.05) and proliferating cells (6.2% vs. 10.6%, P <.05) in the neointima after local application of L-arginine.

CONCLUSION

Reduction of neointimal area was significant for L-arginine and molsidomine but not for r-hirudin. Saline infusion caused significant arterial trauma, resulting in additional neointimal proliferation.

[Molecular radiology. II: Molecular imaging]

The most important strategies for molecular imaging are presented. Processes can now be imaged in vitro and in vivo at the molecular level with the help of modern procedures such as SPECT, PET, MRI, and highly developed optical methods. The ability to view the expression of genes, the pharmacokinetics of gene therapy vectors, of therapeutic DNA, and of classical pharmacons in vivo opens up completely new perspectives for the research on, diagnosis of, and therapy for diseases. The current status of these developments are described, potential fields of use and possibilities for further development are outlined.

Granulocyte-colony stimulating factor in the prevention of postoperative infectious complications and sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). Protocol of a controlled clinical trial developed by consensus of an international study group. Part three: individual patient, complication algorithm and quality manage

GENERAL DESIGN

Presentation of a new type of a study protocol for evaluation of the effectiveness of an immune modifier (rhG-CSF, filgrastim): prevention of postoperative infectious complications and of sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). A randomised, placebo controlled, double-blinded, single-centre study is performed at an University Hospital (n = 40 patients for each group). This part presents the course of the individual patient and a complication algorithm for the management of anastomotic leakage and quality management.

OBJECTIVE

In part three of the protocol, the three major sections include: The course of the individual patient using a comprehensive graphic display, including the perioperative period, hospital stay and post discharge outcome. A center based clinical practice guideline for the management of the most important postoperative complication--anastomotic leakage--including evidence based support for each step of the algorithm. Data management, ethics and organisational structure.

CONCLUSIONS

Future studies with immune modifiers will also fail if not better structured (reduction of variance) to achieve uniform patient management in a complex clinical scenario. This new type of a single-centre trial aims to reduce the gap between animal experiments and clinical trials or--if it fails--at least demonstrates new ways for explaining the failures.

The use of gadolinium chelates for X-ray digital subtraction angiography

RATIONALE AND OBJECTIVES

To evaluate the feasibility and safety of using gadolinium chelates for x-ray digital subtraction angiography (DSA) in patients with contraindications to iodinated contrast material.

METHODS

We performed 30 DSAs in 22 patients (5 females, 17 males; mean age 64.9 years) with contraindications to iodinated contrast media (renal insufficiency: n = 28; hyperthyroidism: n = 1; contrast allergy: n = 2). Gadolinium chelates were administered as 0.5 mol/L solutions (mean volume of gadolinium chelates per patient was 34 +/- 19 mL). Gadolinium chelates were the sole contrast agent in 17 examinations, were used in conjunction with carbon dioxide (CO2) in 8 studies, (mean 212 +/- 226 mL), and were combined with the restricted use of nonionic iodinated contrast (mean 12.8 +/- 4.7 mL) in 6 examinations. We carried out 15 diagnostic angiographies and 15 percutaneous transluminal angioplasties.

RESULTS

Use of gadolinium chelates allowed us to obtain diagnostic angiographic images in all cases. However, the quality of angiograms was inferior compared with that obtained with iodinated contrast agents and superior compared with CO2 as the contrast material. Adverse events were not noted. Mean serum creatinine was 2.6 +/- 1.5 mg/dL before and 2.3 +/- 1.0 mg/dL after DSA. No patient developed contrast-induced nephropathy.

CONCLUSIONS

Gadolinium chelates produce an x-ray DSA intermediate in image quality between iodinated contrast and CO2. Digital subtraction angiography with intra-arterial gadolinium chelate administration may offer an alternative to iodinated contrast material in patients with contraindications to iodine.