[Periinterventional prophylactic antibiotics in radiological port catheter implantation]

PURPOSE

To evaluate whether catheter-related infections after radiologically placed port catheters can be reduced by single-shot periinterventional antibiosis.

MATERIALS AND METHOD

Between January and September 2002, 164 consecutive patients with indication for central venous port catheter implantation were included in the present study. During implantation the interventional radiologist was responsible for deciding whether to administer a prophylactic single-shot antibiosis. The prophylactic antibiosis entailed intravenous administration of ampicillin and sulbactam (3 g Unacid, Pfizer) or 100 mg ciprofloxacine (Ciprobay, Bayer) in the case of an allergy history to penicillins. Catheter-related infection was defined as a local or systemic infection necessitating port catheter extraction.

RESULTS

Indication for port catheter implantation was a malignant disease requiring chemotherapy in 158 cases. The port catheter (Chemosite [Tyco Healthcare] [n = 123], low-profile [Arrow International] [n = 35], other port system [n = 6]) was implanted via sonographically guided puncture of the right jugular vein in 139 patients, via the left jugular vein in 24 cases and via the right subclavian vein in one patient. 75 patients received periinterventional prophylactic antibiosis (Unacid [n = 63] Ciprobay [n = 12]) and 89 patients did not receive antibiosis. The prophylactic antibiosis caused a minor allergic reaction in one patient that improved with antihistamic and corticoid medication. A total of 7 ports, 6 without prophylactic antibiosis versus one with periinterventional prophylaxis, were extracted due to infectious complications.

CONCLUSION

Single-shot periinterventional prophylactic antibiosis can reduce early and late infectious complications after radiological-interventional placement of central venous port catheters.

Image-guided surgery of liver metastases by three-dimensional ultrasound-based optoelectronic navigation

BACKGROUND

Vessel-oriented surgery and tumour-free resection margins are essential for resection of liver metastases to preserve liver parenchyma and improve oncological outcome. Preoperative three-dimensional models reconstructed from imaging data could facilitate surgical planning with the use of navigation technology.

METHODS

Thirty-three patients with central and/or impalpable liver metastases were scheduled for navigated hepatic resection. Intraoperative three-dimensional ultrasonography and an infrared-based optical tracking system were used for data registration and image-guided surgery. Postoperative three-dimensional data were compared with the preoperative virtual surgical plan to assess the accuracy of navigation, and clinical results were compared with those of a matched control group of 32 patients.

RESULTS

Navigation was successful in 32 of 33 patients. Realization of the preoperative plan and R0 resection was achieved in 30 of these 32 patients. The median discrepancy between the planned and actual vascular dissection level was 6 (range 0-11) mm. There was a reduced rate of R1 resection in the navigated group compared with the control group (two versus four patients), and more parenchyma was preserved.

CONCLUSION

Three-dimensional ultrasound-based optoelectronic navigation technology improves intraoperative orientation and enables parenchyma-preserving surgery with high precision.

Image guided respiratory gated hypofractionated Stereotactic Body Radiation Therapy (H-SBRT) for liver and lung tumors: Initial experience

To evaluate our initial experience with image guided respiratory gated H-SBRT for liver and lung tumors. The system combines a stereoscopic x-ray imaging system (ExacTrac X-Ray 6D) with a dedicated conformal stereotactic radiosurgery and radiotherapy linear accelerator (Novalis) and ExacTrac Adaptive Gating for dynamic adaptive treatment. Moving targets are located and tracked by x-ray imaging of implanted fiducial markers defined in the treatment planning computed tomography (CT). The marker position is compared with the position in verification stereoscopic x-ray images, using fully automated marker detection software. The required shift for a correct, gated set-up is calculated and automatically applied. We present our acceptance testing and initial experience in patients with liver and lung tumors. For treatment planning CT and Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) as well as magnetic resonance imaging (MRI) taken at free breathing and expiration breath hold with internal and external fiducials present were used. Patients were treated with 8-11 consecutive fractions to a dose of 74.8-79.2 Gy. Phantom tests demonstrated targeting accuracy with a moving target to within +/-1 mm. Inter- and intrafractional patient set-up displacements, as corrected by the gated set-up and not detectable by a conventional set-up, were up to 30 mm. Verification imaging to determine target location during treatment showed an average marker position deviation from the expected position of up to 4 mm on real patients. This initial evaluation shows the accuracy of the system and feasibility of image guided real-time respiratory gated H-SBRT for liver and lung tumors.

Magnetic resonance-guided biopsy of suspicious breast lesions with a handheld vacuum biopsy device

PURPOSE

To evaluate a handheld vacuum-assisted device system for magnetic resonance image (MRI)-guided breast lesion biopsy.

MATERIAL AND METHODS

In 32 patients, a total of 42 suspicious breast lesions (mean diameter 7.5 mm for mass lesions, 11.6 mm for non-masslike diffuse lesions) seen with MRI (no suspicious changes in breast ultrasound or mammography) were biopsied (27 lateral, 15 medial) using a 10G vacuum-assisted breast biopsy device under MR guidance. Histology of biopsy specimens was compared with final histology after surgery or follow-up in benign lesions.

RESULTS

In all biopsies, technical success was achieved. Histology revealed 11 lesions with ductal carcinoma in situ (DCIS) or invasive cancer, three with intermediate lesions (LCIS) and 28 with benign breast lesions (adenosis, infected hematoma). In one patient with discordant results of MRI and histology, surgical excision revealed medullary cancer. In the follow-up (mean 18 months) of the histological benign lesions, no breast cancer development was observed. Besides minor complications (hematoma, n = 6), with no further therapeutic interventions, no complications occurred.

CONCLUSION

MRI-guided breast lesion biopsy using a handheld vacuum-assisted device is a safe and effective method for the work-up of suspicious lesions seen with breast MRI without changes in mammography or ultrasound. In the case of discordant histology of vacuum biopsy and breast MRI appearance, surgical excision is recommended.

Intraoperative ductoscopy in women undergoing surgery for breast cancer

BACKGROUND

Extensive intraductal disease represents an important clinical problem in the management of patients with invasive or in situ breast cancer. The purpose of this study was to determine the value of intraoperative ductoscopy for detection of intraductal neoplasia in women with breast cancer.

METHODS

Intraoperative ductoscopy was performed in 54 women undergoing operation for breast cancer. A rigid gradient index microendoscope (0.7 mm) was used for all examinations. Ductoscopy findings were documented prospectively and correlated with preoperative mammography and histology of the resection specimen.

RESULTS

Fifty of 54 (92%) patients were examined successfully. Ductoscopy identified intraductal lesions (ie, red patches, ductal obstruction, or microcalcifications) in 25 of 50 (50%) patients. Abnormal ductoscopic appearance was found in 19 of 23 patients with extensive intraductal disease (82%). Mammographic microcalcifications were observed in 15 of those 19 patients and in 3 patients with normal ductoscopy (78%). The combined sensitivity of both methods was 95%. Patients with an abnormal ductal appearance on ductoscopy, compared with those with a normal ductal appearance, had a greater incidence of extensive intraductal spread of cancer (76% vs 16%) and a greater incidence of positive surgical margins (44% vs 12%).

CONCLUSIONS

High-resolution ductoscopy is able to detect extensive intraductal disease in a considerable number of women with breast cancer. In selected patients, a combination of both preoperative imaging and intraoperative ductoscopy may help to avoid incomplete resections and re-excisions.

Registration of different phases of contrast-enhanced CT/MRI data for computer-assisted liver surgery planning: Evaluation of state-of-the-art methods

The exact localization of intrahepatic vessels in relation to a tumour is an important issue in oncological liver surgery. For computer-assisted preoperative planning of surgical procedures high quality vessel models are required. In this work we show how to generate such models on the basis of registered CT or MRI data at different phases of contrast agent propagation. We combine well-established intensity-based rigid and non-rigid registration approaches using Mutual Information as distance measure with different masking strategies as well as intensity inhomogeneity correction for MRI data. Non-rigid deformations are modelled by multilevel cubic B-splines. Quantitative evaluations of 5 MRI and 5 CT image pairs show that the liver moves rigidly 7.2 (+/- 4.2) mm on average, while the remaining non-rigid deformations range from 1.4-3 mm. As a result we find that masked rigid registration is necessary and in many cases also sufficient on clinical data. After non-rigid registration the matching shows no deviations in most cases.

Use of Semiflexible Applicators for Radiofrequency Ablation of Liver Tumors

PURPOSE

To evaluate the feasibility and potential advantages of the radiofrequency ablation of liver tumors using new MRI-compatible semiflexible applicators in a closed-bore high-field MRI scanner.

METHODS

We treated 8 patients with 12 malignant liver tumors of different origin (5 colorectal carcinoma, 2 cholangiocellular carcinoma, 1 breast cancer) under MRI guidance. Radiofrequency ablation (RFA) was performed using 5 cm Rita Starburst Semi-Flex applicators (Rita Medical Systems, Milwaukee, WI, USA) which are suitable for MR- and CT-guided interventions and a 150 W RF generator. All interventions were performed in a closed-bore 1.5 T high-field MRI scanner for MRI-guided RFA using fast T1-weighted gradient echo sequences and T2-weighted ultra-turbo spin echo sequences. Control and follow-up MRI examinations were performed on the next day, at 6 weeks, and every 3 months after RFA. Control MRI were performed as double-contrast MRI examinations (enhancement with iron oxide and gadopentetate dimeglumine). All interventions were performed with the patient under local anesthesia and analgo-sedation.

RESULTS

The mean diameter of the treated hepatic tumors was 2.4 cm (+/-0.6 cm, range 1.0-3.2 cm). The mean diameter of induced necrosis was 3.1 cm (+/-0.4 cm). We achieved complete ablation in all patients. Follow-up examinations over a duration of 7 months (+/-1.3 months, range 4-9 month) showed a local control rate of 100% in this group of patients. All interventions were performed without major complications; only 2 subcapsular hematomas were documented.

CONCLUSION

RFA of liver tumors using semiflexible applicators in closed-bore 1.5 T scanner systems is feasible. These applicators might simplify the RFA of liver tumors under MRI control. The stiff distal part of the applicator facilitates its repositioning.

[Contrast media pressure injection using a portal catheter system--results of an in vitro study]

PURPOSE

Are implanted central venous port catheters suitable for contrast media pressure (power) injection in computed tomography?

MATERIAL AND METHODS

In an in vitro study 100 ml of contrast medium (Ultravist 370, Schering, Berlin, Deutschland) was injected through 20 different port catheter systems using a power injector (Stellant, Medrad, Inianola, USA) with a pressure limit of 325 PSI. The injection rate was increased from 2 ml/s to 10 ml/s in increments of 2 ml/s. The maximum injection pressure and maximum injection rate were assessed.

RESULTS

An injection rate of 2 ml/s was possible in all catheter systems. Injection rates of 4 ml/s in 18 systems, 6 ml/s in 13 systems and 8 ml/s in 6 systems were achieved. With a given pressure limit of 325 PSI an injection rate of 10 ml/s was not possible in any of the port catheter systems. There were no catheter ruptures, catheter disconnections or contrast extravasations noted.

CONCLUSION

Power injection of contrast media with a pressure limit of 325 PSI seems to be tolerated by port catheter systems. Most of the evaluated port systems allow flow rates suitable for multislice computed tomography requiring rapid contrast injection.

Potenzial der MRT für die Radiofrequenzablation von Lebertumoren

PURPOSE

To present first results of radiofrequency ablation of liver tumors using a new MR compatible applicator.

MATERIALS AND METHODS

We performed 37 interventions in 20 patients (mean age 58.6 years) with primary intrahepatic malignancies or metastases: colorectal carcinoma n = 6, hepatocellular carcinoma n = 3, pancreatic carcinoma n = 4, sarcoma n = 2, cholangiocellular carcinoma n = 1, carcinoma of the tonsil n = 1, breast carcinoma n = 1, gastric carcinoma n = 1, and gastrointestinal stroma tumor n = 1. Interventions were performed under CT-guidance with CT fluoroscopy (n = 32) and under MR-guidance (n = 5) using fast T1-weighted sequences in breath-hold technique. RFA was performed with the RF-generator (150 W) under local anesthesia and sedation using MR compatible applicators (Starburst XL, Rita Medical Systems, USA) together with the appropriate Soft Tissue Introducer System. Intra-interventional control was performed with intrahepatically or intralesionally placed introducer system or applicator. MRI was performed with plain breath-triggered T2-weighted turbo spin echo sequences (TSE T2) with fat saturation.

RESULTS

All interventions were performed without major events. The mean diameter of induced coagulation was 4.0 (+/- 0.7) cm. Repositioning was necessary in 8 interventions (21 %) after detection of residual tumor on an intra-interventional MRI. After a mean follow-up of 6.5 (+/- 1.2) months, the local tumor control rate was 92 %.

CONCLUSION

MR-compatible RF applicators offer the opportunity for intra-interventional detection of residual tumor during RF ablations by use of sensitive MRI sequences. These procedures may lead to a higher confidence in tumour ablation and may reduce the number of re-interventions and local recurrences of intrahepatic tumors.

Weichteilsakrome

Soft tissue sarcomas are characterized by their heterogeneity. With new diagnostic imaging techniques, low- and high-grade components of the tumor can be differentiated. Thus biopsies should be guided by imaging to assure representative specimens. Besides histopathology, the advent of chromosomal and gene expression analysis may allow more accurate classification in the near future. Gene expression profiling has already proven its value by finding new subclassifications in other tumor types. Furthermore, this technique is a promissing tool to predict the response of a tumor to neoadjuvant and adjuvant therapy. Up to now, response evaluation in neoadjuvant therapy is based on tumor size and not on vital tumor cells. Newer techniques (i.e., Magnetic-resonance-Spectroscopy, Molecular Imaging) can show the change of metabolism in neoadjuvant therapy and allow objective, comparative measurement of biological activity. The diagnostic of soft tissue sarcomas implies primarily a multidisciplinary approach for a stage associated therapy.

Langfristige zentralvenöse Zugänge und deren Komplikationsmanagement

The implantation of permanent (> 14 days) central venous catheters is constantly increasing, accelerated by a trend toward outpatient therapies. Subcutaneous tunneled and non-tunneled catheters as well as port systems are available. The interventional radiologist plays an important role in the implantation of central venous catheters as well as in detection and treatment of any complications. Various access ways via peripheral and central veins are described and the implantation techniques for the different systems explained. The use of peel-away sheaths allows the radiologist to implant subcutaneous tunneled catheters via the Seldinger technique without surgical preparation. Procedure-related early and late complications may occur, and the radiologist plays an important role in the surveillance and management of catheter-associated complications. This review demonstrates the different catheter systems and implantation techniques.

Ultraschall- und durchleuchtungsgesteuerte Implantation peripher inserierter zentral-venöser Katheter (PICC)

PURPOSE

Evaluation of ultrasound- and fluoroscopy-guided implantation of peripherally inserted central venous catheters (PICCs).

MATERIALS AND METHODS

In 32 patients (12 males, 20 females; mean age 64.1 +/- 11.9 years) with clinical indication for long term central venous catheter (chemotherapy: N = 5; parenteral nutrition and fluid substitution: N = 26; parenteral pain therapy: N = 1) a PICC was placed by an interventional radiologist using ultrasound guidance.

RESULTS

The placement of the PICC was technically successful in 31 (96.9%) patients, with placement of 20 single-lumen 5F PICCs, 4 double-lumen 6F PICCs and 7 double-lumen 7F PICCs. The mean duration of catheter usage was 28.4 (2 - 161) days with a total of 910 catheter days. No catheter occlusions were recorded. Two patients developed a superficial venous thrombosis of the upper extremity. The resulting thrombotic rate was 2.2 per 1000 catheter days. No catheter associated infection was recorded.

CONCLUSION

The ultrasound guided placement of peripherally inserted central venous catheters (PICCs) via a superficial vein of the upper extremity is a practical alternative to central catheters via central veins.

New Concepts of Staging in Gastrointestinal Tumors as a Basis of Diagnosis and Multimodal Therapy

The therapy of gastrointestinal tumors is becoming more and more sophisticated and complex. This is due to an improved understanding of the pathogenesis of tumors, a more detailed classification and increasing therapeutic options. The basis of optimized therapeutic concepts is the exact evaluation of tumor spread and exact staging. The following review describes some of the most recent staging concepts in gastrointestinal tumors. Multislice computed tomography (CT), positron emission tomography (PET) and new supraparamagnetic iron oxide contrast agents for magnetic resonance imaging enable an increasing quality of the visualization of tumors and metastases. 3D imaging will be used for planning of surgical interventions in the future. Optical coherence tomography may contribute to an improved tumor staging and, thus, to the safety of limited interventions in early oesophageal- and gastric cancer patients. Laparoscopy and laparoscopic ultrasound become increasingly important for the identification of small metastases in the peritoneum, in lymph nodes and in the liver. The sentinel lymph node concept will contribute to an improved staging and individualized therapy as well.

Central venous access catheters: radiological management of complications

A great variety of central venous access devices such as tunneled and non-tunneled central venous catheters (CVC) as well as port systems are implanted by interventional radiologists at an increasing rate. There are some possible immediate, early, and late complications related to the implantation technique, care, and maintenance of CVCs. This review will illustrate possible complications of CVCs and will discuss risk factors. Different strategies will be shown regarding the prevention and treatment of complications.

Bildgebende Diagnostik im pr�operativen Staging beim Rektumkarzinom

Thorough clinical examination, endorectal ultrasound, and magnetic resonance tomography (MRI) are decisive tools in the pretherapeutic work-up of patients with rectal cancer. Depth of infiltration to the rectal wall as well as involvement of perirectal lymph nodes by the tumor are the key questions to be answered. To receive adequate information from imaging procedures, the right questions need to be asked. The extent of invasion of the rectal wall and exact location of tumor infiltration to neighboring structures can be demonstrated by MRI very well, particularly if imaging planes are acquired at 90 degrees to the position of the rectum. Recent developments in computed tomography (CT) using isotrope voxels allow three-dimensional reconstructions of tumors without loss of imaging quality. Assessment of the primary tumor and its nodal metastases after preoperative radio-(chemo-)therapy is still seriously limited. Fusion of positron emission tomography and CT could be a step towards solving the problem of response assessment in the near future.

Flexible Applikatoren zur Radiofrequenzablation (RFA) bei Lebertumoren

PURPOSE

To report our experience with flexible applicators in radiofrequency ablation (RFA) of hepatic tumors.

MATERIALS AND METHODS

In 6 liver tumors in 6 patients, a flexible RFA-applicator system (RITA StarBurst FLEX, RITA Medical Systems, Mountain View, CA, USA) was placed under CT guidance. The Seldinger technique with an 11G access system (RITA StarBurst Access) was used to place the application system into the liver. Before and within a week after the ablation, all tumors were investigated with contrast-enhanced MRI.

RESULTS

The Seldinger technique accommodated the placement of a thin 17.5-gauge needle for the initial puncture, enabling easy adjustment of the position of the needle. The flexible applicator of the RFA system could be placed in 4.5 (+/- 1.8) minutes on average.

CONCLUSION

Flexible applicators facilitate CT-guided RFA and can be placed using the Seldinger technique.

Die transjuguläre Implantation venöser Portkathetersysteme

PURPOSE

Prospective analysis of success and complication rates of chest port implantation via the internal jugular vein.

MATERIALS AND METHODS

In 50 consecutive patients (25 men, 25 women; mean age 61 +/- 14 years) the internal jugular vein was punctured under ultrasound guidance. Through this access, a port system was inserted and the catheter tip was placed at the cavoatrial junction. The port reservoir was implanted into a subcutaneous infraclavicular pocket and fixed to the fascia of the pectoralis muscle. Indications for port implantation were chemotherapy (n = 46), total parenteral nutrition (n = 2) or intravenous medication (n = 2).

RESULTS

A chest port catheter system was successfully implanted in all 50 patients. The mean duration of placement was 90 +/- 65 catheter days. No complications occurred during implantation. In the post-interventional period a single catheter dysfunction occurred (0.22 per 1,000 catheter days). Two local infections occurred in the early post-interventional period (0.43 per 1,000 catheter days). One port system had to be explanted prematurely due to pain.

CONCLUSION

The ultrasound guided puncture of the internal jugular vein enables a safe access for insertion of a central venous port catheter system and is associated with a very low complication rate. Port placement via this access vein should therefore be the primary treatment.

Differenzierung von Leberläsionen mit SPIO-gestützten T1-w und T2-w MRT-Aufnahmen: Eine ROC-Analyse

PURPOSE

The superparamagnetic iron oxide (SPIO) Resovist is a contrast media with shortening of both T(1) and T(2) relaxation time. This study evaluates the impact of SPIO-enhanced T(1)- and T(2)-weighted images for the differentiation of liver lesions.

MATERIALS AND METHODS

SPIO-enhanced MRI examinations (1.5 T, Symphony Quantum) of 61 patients were analyzed. Thirty-seven patients had malignant liver lesions (metastases n = 32, HCC n = 5) proven by biopsy or laparotomy, 11 patients had benign liver lesions (FNH n = 2, hemangiomas n = 4, benign cysts n = 5, normal liver on laparoscopy n = 13). After unenhanced T(1)- and T (2)-weighted imaging, a bolus injection of 1.4 ml SPIO (Resovist) was given, followed by T(1)-weighted imaging at 20 s, 60 s, and 5 min and T(2)-weighted imaging at 10 min post injection. A score from 1 (benign) to 5 (malignant) was used by three blinded radiologist for the ROC analysis of the unenhanced T(1)-/T(2)-weighted images (set 1) and of the combinations of unenhanced T(1)/T(2)-weighted and SPIO T(1)-weighted images (set 2), unenhanced T(1)/T(2) and SPIO T(2)-w images (set 3) and all images (set 4).

RESULTS

The accuracy of plain MRI (set 1: 56 %) was increased by SPIO-enhanced T(1)-weighted images (set 2: 81 %) and SPIO-enhanced T(2)-weighted images (set 3: 90 %). Best results were obtained using unenhanced T(1)-weighted, unenhanced T(2)-weighted and both SPIO T(1)-weighted and T(2)-weighted images (set 4: 93%). The accuracy of predicting histopathologic diagnosis was 91%.

CONCLUSION

For the differentiation of liver lesions, SPIO-enhanced T(2)-weighted images had a greater impact on the accuracy of MRI than T (1)-weighted images, but SPIO-enhanced T(1)-weighted images provided additional information in some patients and should not be deleted.

Intraperitoneal distribution of ultrasound contrast medium imaged with B-mode ultrasound and colour-stimulated acoustic emission imaging

Intraperitoneal port catheter systems for local delivery of cytotoxic drugs require imaging prior to chemotherapy to confirm homogenous distribution of an injected fluid in the entire peritoneal cavity. This study was performed to assess whether contrast-enhanced ultrasound (US) is a suitable imaging modality for this task. Twelve patients with peritoneal carcinosis and an implanted intraperitoneal port catheter system were studied before chemotherapy. Ultrasound examinations were performed after bolus injections of the microbubble contrast medium Levovist. Distribution of the contrast medium in the peritoneal cavity was imaged using B-mode US and colour-stimulated acoustic emission imaging (SAE). Contrast-enhanced CT imaging was used as term of reference for evaluating the US results. Distribution of the microbubbles in the peritoneal cavity was easily detected by both US methods. In 10 of 12 patients a free distribution in all abdominal quadrants was seen with both US techniques. In 2 of 12 patients, CT and US showed contrast medium limited to the perihepatic area. Therapy was stopped and surgical repositioning of the catheter was performed. Ultrasound after intraperitoneal injection of a microbubble contrast agent provides reliable information about the distribution of intraperitoneally injected fluid in the peritoneal cavity. This method is therefore well suited for imaging port catheter systems prior to chemotherapy.

[Multi-slice spiral CT: 3D CT angiography for evaluating therapeutically relevant stenosis in peripheral arterial occlusive disease]

PURPOSE

Evaluation of 3D multislice CT angiography for the assessment of relevant stenoses of pelvic arteries and arteries of the lower extremity in patients with peripheral artery occlusive disease compared to digital subtraction angiography.

METHOD/MATERIALS

For this study we examined 31 patients with peripheral artery occlusive disease. All patients received a multislice helical CT angiography and arterial digital subtraction angiography. Multislice CT angiography was performed with a Somatom Plus 4 Volume Zoom (Siemens, Erlangen, Germany). After test bolus injection of 20 ml Ultravist 370 (Schering AG, Berlin) additional 150 ml were applied with a flow rate of 3 ml/sec and a scan delay between 20-35 sec depending on individual blood circulation time. Collimation was 4 x 2.5 mm with a pitch of 6. Reconstructed slice thickness was 3 mm. 3D reconstructions of arteries of pelvic and lower extremity arteries were performed in volume rendering technique on a 3D Virtuoso workstation (Siemens, Erlangen).

RESULTS

For the assessment of therapeutically relevant stenoses (over 50% reduction of luminal diameter) multislice CT achieved the following results compared to conventional angiography for the diagnosis of stenosis: sensitivity of 86%, specificity of 86% and an accuracy of 72%.

CONCLUSIONS

Multislice helical CT angiography of pelvic arteries and arteries of the thigh represents a reliable means for the detection of relevant stenoses in patients with peripheral occlusive artery disease.

Survey of conventional and spiral ct doses

PURPOSE

To investigate the radiation dose for conventional computed tomography (CT) and spiral CT during different CT examinations at various hospitals and practices.

MATERIALS AND METHODS

CT dose index with an active length of 15 cm was measured in 16 different types of CT scanners by using ionization chamber dosimetry. Twenty-six holders (one who has legal responsibility under national law for a radiologic installation) operating a total of seven conventional and 20 spiral CT scanners were asked for their standard parameters for various CT examinations. Weighted CT dose index and dose-length product were determined for each examination.

RESULTS

For most examinations, the tube current time product was significantly higher for conventional CT than for spiral CT (.002 </= P </=.05). The ratio of section distance to section thickness for conventional CT was significantly lower than the pitch for spiral CT (.001 </= P </=.05). The weighted CT dose index and dose-length product for spiral CT were about half of those for conventional CT. The third quartiles for weighted CT dose index and dose-length product for spiral CT were much lower than those recommended as reference doses.

CONCLUSION

CT examinations with conventional CT scanners are often performed with unnecessarily high radiation dose. For the establishment of reference doses, the radiation dose with spiral CT scanners should be taken into account.

Removal of detergent and solvent from solvent-detergent-treated immunoglobulins

The solvent-detergent (S/D) method was applied for inactivation of lipid-enveloped viruses during the production of immunoglobulins. Amberlite XAD-7 resin was used for removal of solvent (tri-n-butyl phosphate, TnBP) and detergent (Triton X-100) after the performed S/D inactivation procedure. The S/D reagents from the immunoglobulin preparation were adsorbed on Amberlite XAD-7, while immunoglobulins passed through the column and retained their biological activity. Using the method developed here, the final immunoglobulin preparation contains less than 1 ppm of Triton X-100 and less than 2 ppm TnBP.

Ion-exchange chromatography separation of the detergent and the solvent from immunoglobulins after solvent-detergent treatment

For inactivation of lipid-enveloped viruses during the immunoglobulin production, the solvent-detergent (S/D) method was applied. Tri-n-butyl phosphate (solvent) and Triton X-100 (detergent) were removed from S/D treated immunoglobulins by ion-exchange chromatography on Q-Sepharose Fast Flow (FF). During the chromatographic procedure immunoglobulins remained bound on a Q-Sepharose FF, whereas solvent and detergent were eluted by washing with starting buffer. Elution of immunoglobulins was achieved by increasing the ionic strength of the starting buffer. The final immunoglobulin preparation contained less than 10 microg/ml of Triton X-100 and less than 2 microg/ml tri-n-butyl phosphate. It was confirmed that the S/D procedure did not cause a significant change in polymers and specific antibodies content. Immunoglobulin classes were also not affected by the same procedure.

[Nephrolithiasis in "disk-variant" cross-over renal dystopia. Report of a case]

Renal dystopia is a frequent urogenital anomality. Renal dystopia encloses pelvic kidney or malascending kidney, but also rare anomalities like renal duplication or crossed renal dystopia. These allotopias are often diagnosed on routine examination of the urogenital system. We report a case with fused crossed renal dystopia on the left with atypical symptoms of nephrolithiasis and give a summery of the embryological origin.

Changes at the extracellular matrix during acute and chronic rejection in human liver transplantation

We have previously observed changes at the extracellular matrix (ECM) which significantly correlated with the extent of preservation and reperfusion injury. In the present study, we attempted to investigate whether the ECM may be also involved in the pathophysiological sequelae of acute and chronic rejection. Of 81 patients monitored for the ECM parameters laminin, hyaluronic acid, fibronectin receptor, and transforming growth factor (TGF)-beta, 28 patients developed acute rejection (< 1 month), in 14 patients (17.4%) acute rejection was steroid resistant, 4 patients (4.5%) developed early chronic rejection following acute steroid-resistant rejection. Acute and chronic rejection were confirmed by established clinical and histological criteria. Laminin levels were significantly increased in patients experiencing acute steroid-resistant rejection (4204 +/- 133 ng/ml; P < or = 0.01) compared with patients with steroid-sensitive rejection (1059 +/- 27.3 ng/ ml) and with an uneventful postoperative course (1214 +/- 17.4 ng/ml). No increase in laminin was observed in those four patients who developed early chronic rejection (1099 +/- 58.7 ng/ml). Hyaluronic acid, fibronectin receptor, and TGF-beta levels also increased in patients with acute steroid-resistant rejection; hyaluronic acid: 290 +/- 10.8 micrograms/l vs 154 +/- 13.6 micrograms/l and 131 +/- 11.7 micrograms/l in patients with steroid-sensitive and no rejection, respectively; fibronectin receptor: 1003 +/- 23.5 ng/ml vs 573 +/- 24.8 ng/ml and 428 +/- 13.6 ng/ ml in patients with steroid-sensitive and no rejection, respectively; and TGF-beta: 393 +/- 14.9 pg/ml versus 315 +/- 10.7 pg/ml and 233 +/- 8.9 pg/ml in patients with steroid-sensitive and no rejection, respectively. A further increase in hyaluronic acid levels was observed in patients who developed early chronic rejection, while fibronectin receptor and TGF-beta levels remained low, similarly to laminin levels. The increase in laminin, hyaluronic acid, fibronectin receptor, and TGF-beta during acute steroid-resistant rejection may be stimulated by the rejection-related release of cytokines and adhesion molecules which paralleled the increase in ECM parameters. The lack of increase in laminin and fibronectin receptor levels in those patients who developed early chronic rejection may reflect an inability to recover from acute rejection.

Characterization of F VIII concentrates produced by two methods incorporating double virus inactivation

The trend toward the production of high purity factor VIII concentrates for clinical use is still in progress. Although all plasma derivatives must undergo viral inactivation procedures, the possibility of transmission of viral diseases is not completely eliminated. In order to reduce such risk, we have included double virus inactivation in the procedure of factor VIII concentrate production. In a scale-up procedure for isolation of factor VIII cryoprecipitate, two methods were used. The first is based on the chromatographic purification of factor VIII after pasteurization of cryoprecipitate solution and solvent/detergent (S/D) inactivation of viruses. The second is based on multistep precipitation of factor VIII by sodium chloride and glycine. Viral inactivation was performed by combination of S/D treatment and heating of final freeze-dried product 30 min at 100 degrees C. The typical yield of factor VIII activity in the freeze-dried product was about 20% for the first method, and 25-30% for the second. Electrophoretic analyses of both factor VIII preparations by SDS-PAGE and IEF show very low content of contaminant proteins, in accordance with observed 400-650-fold increase of their specific activity over plasma. Both factor VIII products were stable in the liquid state for more than 24 h at room temperature. The final products, after double viral inactivation, are considered to be suitable for clinical evaluations.