Biomedical subjects

T Schmitz-Rode

Publications and source records attributed to T Schmitz-Rode.

At least 37 records · Page 2Linked to original sources

PubMed2001

Multi-slice CT urography after diuretic injection: initial results.

PURPOSE: To investigate the feasibility of CT urography (CTU) using a multi-slice (MS) scanner and to find out whether a low-dose diuretic injection is advantageous for the opacification of the urinary tract. METHODS: MS-CTU was performed in 21 patients with urologic diseases. In 5/21 patients, 250 ml of physiologic saline Solution were injected. In 16/21 patients, 10 mg of furosemide were injected 3-5 min before contrast material administration. A 4 x 2.5 mm collimation with a pitch of 1.25 and a tube current of 100-150 mA were used. Scan time was 12-16 sec. 3 mm thin axial images with an overlap of 67% were reconstructed. Multiplanar maximum intensity projection (MIP) images were postprocessed to obtain urographic views. Bone structures were eliminated using the volume-of-interest method. RESULTS: Furosemide-enhanced MS-CTU achieved either near complete or complete opacification in 30/32 (94%) ureters and in 32/32 (100%) pelvicaliceal systems up to a serum creatinine of 150 mumol/l. In our series, only one CTU scan per patient was needed to obtain a diagnostic urogram after 10 min of contrast material injection. Ureteral compression was not necessary. When physiologic saline solution was used instead of furosemide, the radiopacity inside the enhanced pelvicalices was 4-5 times higher and more inhomogeneous. Diuretic-enhanced MS-CTU was more accurate in the depiction of pelvicaliceal details. In combination with furosemide, calculi were well identified inside the opacified urine and were safely differentiated from phleboliths. Postprocessing times of up to 20 minutes were problematic as were contrast-enhanced superimposing bowel loops on MIP images. CONCLUSION: Preliminary results demonstrate a good feasibility of furosemide-enhanced MS-CTU for obtaining detailed visualization of the entire upper urinary tract.

Adult↗

PubMed2001

[Magnetic resonance tomography imaging of the inner ear of patients with sensorineural hearing loss or vertigo].

BACKGROUND: Progress in surgical techniques in the temporal bone has lead to the demand of exact delineation of this complex anatomical region for preoperative planning. The aim of this study was to assess the potential of a three-dimensional T2 weighted turbo-spin-echo-sequence to depict anatomical details and pathological changes of the inner ear. METHODS: Twenty-five patients presenting with sensori-neural hearing loss and/or vertigo were included in this study. A T2 weighted turbo-spin-echo-sequence was carried out on a 1.5 T imager, employing a surface coil with a diameter of 8 cm. The scan parameters were set as follows: TR 2000, TE 500, scan matrix 128 x 128, field of view 90 mm, slice thickness 0.66 mm, NSA 4. In addition, 3D maximum-intensity-projections (MIP) were created, using these data as source images. RESULTS: Image quality was excellent in all 25 cases. The 2.5 cochlear windings, modiolus, vestibule with saccule and utricle all three semicircular canals, crus commune and the facial nerve and vestibulocochlear nerve in the inner auditory canal were clearly delineated in all patients. The cochlear aqueduct was seen in 32% (8 cases), while the vestibular aqueduct was delineated in 16% (4 cases) in this series. In MIP, the entire labyrinth was shown in a single view. In 22 patients regular morphology was found, while in three cases pathological changes were detected (an enlarged vestibular aqueduct and saccus in one patient, partial fibrous obliteration of the labyrinth in two patients). CONCLUSIONS: The introduced TSE sequence can be used to delineate the anatomy of the inner ear as well as pathological changes. The technique appears to be useful for preoperative planning.

Adolescent↗

PubMed2001

Implantation of a new access device for hemodialysis (Dialock): initial experience in 5 patients.

PURPOSE: A new hemodialysis access port system was implanted. METHODS: The Dialock consists of a port-like double-valve, implanted subcutaneously below the clavicle, which is attached to two catheters, placed in the right atrium via the jugular vein. The device has been implanted in 5 patients (4 female, 1 male). RESULTS: In all 5 patients the implantation of the catheters and the port was technically successful. Total average duration of dialysis was 3.6 months. Two patients developed a port pocket hematoma 10-14 days post implantation, one of them required surgical revision. One port was explanted due to septicemia, whereas a port infection was not confirmed. One patient showed a thrombotic occlusion of both catheter tips 8 days after implantation, fixed by catheter exchange. Another patient presented with slight migration of the port catheters, which was managed by refixation of the port within the pocket. Beside these complications, the devices were working well. CONCLUSION: The Dialock system offers an interesting alternative to external catheters for hemodialysis. With respect to the complications it deserves further studies to determine its future role in the field of vascular access.

Catheters, Indwelling↗

PubMed2001

[The influence of motion artifacts conditioned by reconstruction, on the coronary calcium score in multislice spiral CT].

UNLABELLED: The influence of motion artifacts conditioned by reconstruction, on the coronary calcium score in multislice spiral CT. PURPOSE: A major problem of the quantification of coronary calcifications is a high variability of the coronary calcium score between recurrent examinations and different observers. Aim of our study is to evaluate the influence of different RR-intervals on the coronary calcium score utilizing retrospectively gated Multislice Spiral CT (MSCT) data sets. MATERIALS AND METHOD: 50 consecutive patients underwent MSCT examination (Somatom Volume Zoom, Siemens, Forchheim, G) utilizing a standardized scan protocol (4 x 2.5 mm collimation, 3 mm increment, tube current 133 mAs, tube voltage 120 kV). Retrospectively gated image reconstruction was performed every 10 % of the RR interval. Coronary calcification was evaluated by the Agatston score. Coronary risk assessment was performed in all patients with image reconstruction beginning at 80 % of the RR interval. The reconstruction intervals with the least motion artifacts were identified and chosen as reference for a reevaluation of the coronary risk. The results of different reconstruction times were compared. RESULTS: The mean calcium score was 551.6. The calcium score varied between 512.2 (90 %) and 571.7 (70 %), depending on the image reconstruction interval. Compared to the mean calcium score a new classification of the coronary risk was necessary in 7/50 of the patients at 80 % reconstruction interval, and in 2/50 of the patients at 50 % of the RR interval, respectively. CONCLUSION: Movement of the coronary arteries at different image reconstruction intervals has an important influence on the coronary calcium score. Based on our data, we propose image reconstruction at 50 % of the RR interval for evaluation of the coronary calcium score by MSCT.

Adult↗

PubMed2001

Navi-ball: a new guidance device for CT-directed punctures.

RATIONALE AND OBJECTIVES: A new navigation system (Navi-Ball) for computed tomography (CT)-guided punctures was tested clinically. METHODS: The device consists of a transparent hemisphere with an angular scale. The hemisphere is fluid filled and contains a bubble indicating the angulation. The system works as a circular spirit level. Adapted to the handle of the needle, it allows needle adjustment according to the planned puncture path on the CT image. The system was tested in 36 patients who had 40 procedures. The needle deviation (in relation to the planned course of the needle) was measured in two rectangular planes. RESULTS: Without requiring preparation time, the guidance system allowed rapid and easy performance of the puncture. First-time needle placement in a double-angulated approach led to a deviation of the needle from the planned path ranging from 0.2 degrees to 4.6 degrees (mean 2.1 degrees, SD 1.4 degrees ) in the axial plane and from 0.4 degrees to 4.0 degrees (mean 2.3 degrees, SD 1.2 degrees). CONCLUSIONS: This "low-tech" system offers easy to use guidance by a single operator and provides for adequate accuracy of first-time needle placement.

Equipment Design↗

PubMed2001

Individually adapted examination protocols for reduction of radiation exposure in chest CT.

RATIONALE AND OBJECTIVES: To develop a simple directive for the reduction of radiation exposure without loss of diagnostic information in routine chest CT examinations. METHODS: Two hundred fifty adult patients (164 male, 86 female) were entered into a prospective trial. All examinations were performed with a multislice CT technique (Somatom Volume Zoom, Siemens). Four groups of 50 patients each were scanned with patient-related specific parameters: individual mA-s values were derived from the estimated body weight: kilograms + 10, +/- 0, - 10, and - 20 mAs. The results were compared with those of 50 patients who were examined by a standard chest protocol by using the parameters 120 mAs and 140 kV. All other parameters including the tube voltage were kept constant. Subjective image quality was rated on a three-point scale: 1 = excellent, 2 = fair, 3 = nondiagnostic. In addition, objective criteria based on signal-to-noise measurements were assessed by using a region-of-interest methodology. RESULTS: Image quality was sufficient in all cases. Mean subjective gradings of image quality, based on soft-tissue window settings, were 1.1 for the 120-mAs protocol, 1.1 for the (body weight [kg] + 10) mAs protocol, 1.1 for the (body weight [kg] +/- 0) mAs protocol, 1.3 for the (body weight [kg] - 10) mAs protocol, and 1.2 for the (body weight [kg] - 20) mAs protocol. Objective criteria based on noise measurements showed mean +/- standard deviation values of 5.7 +/- 0.8 Hounsfield units (HU) for the 120-mAs protocol. For the reduced-dose protocols, values were calculated as 7.6 +/- 1.2 HU (group + 10), 7.9 +/- 1.3 HU (group +/- 0), 8.7 +/- 1.2 HU (group - 10), and finally 9.1 +/- 1.3 HU (group - 20). The best correlation for an entire subgroup was achieved with the - 10 protocol (body weight [kg] - 10) mAs, with nearly constant noise related to body weight in all patients. CONCLUSIONS: By deriving mAs values from body weight estimation, an individually adapted protocol for chest CT can be recommended and easily employed in a clinical setting. With an adaptation of the tube current-time product based on the estimated body weight of the patient - 10 (body weight [kg] - 10 mAs), a well-balanced examination without significant loss of information, even in soft-tissue window settings, can be performed with this particular scanner. For this adapted mAs protocol, a mean reduction of radiation exposure of 45% was achievable, compared with the standard protocol. A maximum decrease per case down to 31 mAs was obtained, without relevant loss of image quality. Therefore, for other types of CT scanners, analogous protocols may be adapted.

Adult↗

PubMed2000

Potential of a new laser target system for percutaneous CT-guided nerve blocks: technical note.

A prototype of a laser target device was used for CT-guided nerve blocks in a preliminary series of nine interventions. The system provides guidance from any possible approach. High accuracy of needle insertion was achieved; the average deviation of the planned from the actual angle was 1.4 degrees. The target device is valuable for facilitating minimally invasive therapy and can decrease the time required for the procedure.

Adult↗

PubMed2000

Massive pulmonary embolism: percutaneous emergency treatment by pigtail rotation catheter.

OBJECTIVES: This study was designed to assess the feasibility, efficacy and safety of mechanical fragmentation of pulmonary emboli using a new rotational pigtail catheter system. BACKGROUND: Acute massive pulmonary embolism associated with right ventricular dysfunction is frequently lethal, despite high-dose thrombolytic therapy. Adjunctive catheter fragmentation may prevent a fatal outcome. METHODS: In 20 patients (age 58.9+/-10.5 years) with severe hemodynamic impairment, massive pulmonary emboli were fragmented by mechanical action of the rotating pigtail. Fifteen patients received thrombolysis after embolus fragmentation or no thrombolysis at all (noninterference group). RESULTS: Prefragmentation pulmonary arterial occlusion was 68.6 +/- 11.3% for both lungs. Pulmonary placement and navigation of the fragmentation catheter was easy and rapid. Fragmentation time was 17+/-8 min. The noninterference group showed a decrease pre- to postfragmentation of shock index from 1.28+/-0.53 to 0.95+/-0.38 (p = 0.011), mean pulmonary artery pressure from 31+/-5.7 to 28+/-7.5 mm Hg (p = 0.02) and a recanalization by fragmentation of 32.9+/-11.8% (mean angiographic score per treated lung from 7.4 to 5.0). Overall mortality was 20%. CONCLUSIONS: Fragmentation by pigtail rotation catheter provided for a rapid and safe improvement of the hemodynamic situation and an average recanalization of about one-third of the pulmonary embolic occlusion. The method appears useful especially in high-risk patients threatened by right ventricular failure, to accelerate thrombolysis, and as a minimal-invasive alternative to surgical embolectomy.

Aged↗

PubMed2000

Recanalization of thrombosed dialysis access with use of a rotating mini-pigtail catheter: follow-up study.

PURPOSE: To evaluate the feasibility, efficacy, and safety of mechanical thrombectomy of occluded dialysis access with use of a rotating mini-pigtail catheter. MATERIALS AND METHODS: Thrombus was fragmented by mechanical action of the rotating pigtail tip (5-mm diameter), while the guide wire exited a sidehole at the pigtail curvature and served as a fixed rotation axis. Twenty-six procedures were performed in 22 patients (12 men, 10 women; mean age, 55.5 years). Native fistulas were treated in 15 instances, polytetrafluoroethylene (PTFE) grafts were treated in 11 instances. Average occlusion time was 20 hours +/- 13 (range, 5-46 hours), average occlusion length was 25.6 cm +/- 10.1 (range, 6-45 cm). Thrombus fragmentation was followed by balloon angioplasty of underlying stenoses. RESULTS: In all 26 procedures, the dialysis access was successfully declotted with subsequent dialysis using the access (clinical success rate, 100%). Handling of the mini-pigtail catheter was simple and rapid, regardless of whether a graft or a native fistula was treated. Average duration of the intervention was 118 minutes +/- 30. Mean primary patency was 165 days +/- 167. Primary patency rate was 82% at 30 days, 65% at 3 months, and 47% at 6 months. There was no evidence of complications due to the thrombus fragmentation procedure. CONCLUSION: The results suggest that declotting of occluded dialysis grafts and fistulas with the mini-pigtail catheter is as effective and safe as other more established percutaneous therapies. It may serve as an easy-to-handle, low-budget alternative to current thrombectomy devices.

Adult↗

PubMed2000

[Initial experiences with a new optical target system (SimpliCT) for CT-guided punctures].

PURPOSE: To evaluate the prototype of a new optical target device for CT-guided punctures and interventions. METHODS: An optical target device for CT-guided punctures was applied in 24 interventions. The system consists of a laser target device mounted on a stand. The biopsy needle is adjusted according the course of a laser beam. The target angle has to be adjusted on the laser unit. The laser carrier can be moved along an 90 degrees-angled rail, allowing punctures from any angle in plane. Furthermore, angulation in the z-plane is possible, supporting interventions with gantry tilt. Size and depth of the target lesions, the planned and the actual angle of the inserted needle, the numbers of corrections of the needle position, and the time required for the puncture were evaluated. The user rated the benefit of the system and the ease of the application. RESULTS: All 24 interventions were carried out successfully. The mean difference between the planned and the actual angle of the needle was 1.3 degrees (SD: 0.7 degree). The system was considered as easy to handle and as a valuable aid. CONCLUSIONS: The laser target device is a simple navigation system which allows accurate positioning of a needle. Requiring an acceptable low preparation time, it easily can be integrated into the procedure.

Adult↗

PubMed2000

[Percutaneous transjugular thrombectomy in iliocaval thrombosis-- initial experience with a newly developed 12F balloon sheath].

PURPOSE: To evaluate the feasibility of percutaneous thrombectomy for the removal of floating iliocaval thrombi using a balloon sheath. MATERIALS AND METHODS: A newly developed balloon sheath (inner diameter: 12-F; outer diameter: 18-F) was tested in two patients with extensive iliocaval thrombosis. Mechanical thrombectomy was performed due to recurrent pulmonary embolism under therapeutic anticoagulation in antiphospholipid-antibody syndrome and, respectively, paraneoplastic thrombosis without a decrease of fresh thrombus mass in spite of pharmacological treatment. Via a transjugular access (20-F), the sheath was advanced retrogradely into the inferior vena cava. After blocking of the vessel, mechanical fragmentation was performed through the working channel coaxially, using a temporary vena cava filter as a rotating basket (max. diameter: 30 mm). Residual thrombus fragments were removed by aspiration. RESULTS: The thrombectomy balloon sheath tested allowed a complete removal of fresh thrombi after fragmentation. In addition, older clot material was obtained. Balloon occlusion prevented the central embolization of thrombus fragments. Clinical signs indicating pulmonary embolism were not seen. The fluid loss due to aspiration was negligible. CONCLUSIONS: The newly developed 12-F balloon sheath proved to be efficient for the extraction of large thrombi. Balloon occlusion safely prevented central embolization of thrombus fragments proximal to the sheath.

Aged↗

PubMed2000

[Nuclear magnetic resonance tomography imaging and functional diagnosis of the eustachian auditory tube].

PURPOSE: To develop and evaluate a protocol for the anatomic depiction and functional testing of the auditory tube with the use of MR imaging. METHODS: Eleven volunteers were included into this study. For the morphological assessment, the imaging protocol included axial and coronal T2-weighted turbo-spin echo sequences (TR/TE = 3194/100 ms) and a T1-weighted gradient echo sequence (TR/TE = 42/4.6 ms). For the functional test a dynamic turbo-gradient echo sequence (TFE) with spectral fat suppression (TR/TE = 15/6.2 ms; 4 sec) was obtained using the single slice technique before and during the Valsalva manoeuvre. RESULTS: With multi-slice sequences, the osseous part of the auditory tube, the tubal cartilage (middle and lateral lamina), the ciliated epithelium, Ostmann's adipose body and the levator and tensor veli palatini muscles were delineated in all cases. During the Valsalva test, opening of the auditory tube was demonstrated in 20 of the 22 investigated sides using the dynamic TFE single slice sequence. CONCLUSIONS: The introduced MRI protocol allow visualization of the opening of the auditory tube and provides detailed anatomical information of the nasopharynx. Comprehensive morphological and functional evaluation of the auditory tube becomes possible within a single examination'.

Adult↗

PubMed2000

[Mono-contrast distension study of the small intestine. Comparison of conventional small bowel follow-through with enteroclysis].

PURPOSE: Development of a new monocontrast examination of the small bowel. MATERIAL AND METHODS: The new examination was applied to 20 patients with suspected bowel obstruction or inflammatory bowel disease. A contrast mixture, containing gelatin, a water-soluble contrast medium (Peritrast) and water (GPW-mixture) was given over an intestinal tube. The viscosity of the new contrast mixture was measured by rotation and flow viscosimetry. The diagnostic value and the degree of small bowel distension were determined independently by 3 examiners. By comparison 20 randomized selected small bowel follow-through examinations (SBFT) and 20 small bowel enemas were examined. Special questionnaires were used to determine subjective compatibility and discomfort. RESULTS: Due to the viscosity of the new contrast medium and the administration over an intestinal tube, a good bowel distension was achieved with the GPW mixture. The bowel distension (p: < 0.01) and the diagnostic value (p: < 0.01) of the new examination in comparison to the SBFT was characterized as being significantly better. In comparison to the small bowel enema, distension was not significantly better (p: 0.31-1.0). The diagnostic value of the small bowel enema was characterized as significantly better by one of the three examiners in comparison to the new monocontrast-distenson examination (p-level < 0.01). CONCLUSION: The monocontrast-distension examination is a potential alternative in patients in whom a small bowel enema with barium sulfate is contraindicated.

Abdomen, Acute↗

PubMed2000

[Changes in the region and the proximal aneurysm neck after endovascular repair of infrarenal aortic aneurysms].

PURPOSE: To analyze short and mid-term changes of the proximal aneurysm neck and to evaluate renal function after endovascular repair of infrarenal abdominal aortic aneurysms. MATERIALS AND METHODS: 24 of 29 patients, who were treated endoluminally with the bifurcated Vanguard Stent graft between 1997 and 1999 underwent spiral CT follow-up after 1, 3, 6 and every 12 months. Mean follow-up period was 10.5 months (3-32 months). Follow-up included spiral CT scanning. The aortic diameter as well as cross-sectional area were measured. Stent graft position and renal perfusion were checked by spiral CT. Serum creatinine levels were determined preoperatively and during follow-up. RESULTS: Supra- and infrarenal aortic sizes remained stable. No correlation to the distance between the stent-graft and the renal arteries was observed. Caudal migration of the stent-graft with an average of 6.5 (3-15) mm occurred in 13 patients. Cranial migration was observed in 3 patients. Uncovered stent wires partially overlapped at least one renal artery in 18 patients. No renal infarction occurred. No significant increase of the serum creatinine level was found. CONCLUSION: The risk of proximal endoleakage due to post-interventional dilatation of the aorta abdominalis seems to be low. Insufficient stent graft fixation requires a wide distance between the proximal end of the stent graft and the aneurysm. In the mid-term uncovered stent wires overlapping the renal arteries had no relevant influence on renal function.

Aged↗

PubMed2000

[Catheter tract embolization after percutaneous transhepatic biliary intervention].

PURPOSE: Evaluation of the feasibility and efficacy of an embolization technique of the transhepatic tract after intervention, in order to prevent peritoneal bile leakage. PATIENTS AND METHOD: Twenty patients (mean age 62 yr) with malignant (17 cases) or benign (three cases) biliary obstruction were treated by percutaneous transhepatic biliary intervention (stent implantation in 17 cases). Mean diameter of the transhepatic tract was 3.2 +/- 0.6 mm. Tract embolization was performed 3.0 +/- 4.0 days after intervention by injecting Histoacryl-Lipiodol via a coaxial catheter-sheath system. RESULTS: Tract embolization was feasible in all cases and resulted in a continuous cast of the catheter tract. There were no signs or symptoms of peritonitis in any of the patients. One patient with stent occlusion developed a biliocutaneous fistula via the former tract after 60 days. CONCLUSION: After embolization of fresh transhepatic tracts there were no signs of leakage during follow-up of the patients. One case with biliocutaneous fistula shows that prevention of leakage is not permanent if biliary reobstruction occurs.

Adult↗

PubMed2000

MRI of the inner ear: comparison of axial T2-weighted, three-dimensional turbo spin-echo images, maximum-intensity projections, and volume rendering.

RATIONALE AND OBJECTIVES: To compare the ability of axial T2-weighted, three-dimensional, turbo spin-echo (3D TSE) images, targeted maximum-intensity projections (MIPs), and 3D volume reconstructions to depict anatomic details of the labyrinth. METHODS: In 24 volunteers, 3D TSE images were obtained. MIPs and 3D volume reconstructions were performed from the acquired data. All images were evaluated by three radiologists independently regarding the visualization of the different anatomic structures. RESULTS: In the axial slices, most anatomic details were visible in comparison with observations by the other modalities. The 2.5 windings of the cochlea were best depicted on the MIPs. Volume reconstructions rendered excellent spatial information regarding the vestibule and semicircular canals and were the only technique that demonstrated all three ampullae in all cases. CONCLUSIONS: Axial TSE images, MIPs, and 3D volume reconstructions are complementary modalities that provide different information. Our results suggest that improved diagnostic information can be obtained by applying these volume visualization reconstruction techniques.

Adult↗

PubMed2000

Percutaneous venous thrombectomy with the use of a balloon sheath: first in vitro investigations of a new low-tech concept.

RATIONALE AND OBJECTIVES: To test mechanical thrombectomy of extensive iliofemoral and iliocaval thrombi in an in vitro flow model with the use of 12F and 18F balloon sheaths. METHODS: Newly developed 12F and 18F sheaths were evaluated in four vessel models (simulation of femoral, iliofemoral, iliocaval, and caval thrombi by clotted bovine blood in a flow model). After retrograde insertion of the sheath and blocking of the vessel proximal to the thrombus by inflating the balloon, mechanical fragmentation was performed coaxially through the sheath lumen by using a 7F pigtail rotation device. With an occlusion balloon catheter, residual thrombi were withdrawn to the orifice of the sheath and aspirated. Twelve silicone tubes occluded by thrombi were recanalized in each setting. In the latex model, seven recanalizations were performed. RESULTS: All clots were removed completely within a treatment duration of 2 to 14 minutes. Fluid loss during the procedure was 29.6 to 129.3 mL for the femoral flow model, 61.9 to 137.2 mL for the iliofemoral model, 74.5 to 163.4 mL for the iliocaval model, and 102.7 to 236.7 mL for the caval model. No fragments were washed downstream. In four settings, small residual thrombi were attached to the balloon after deflation of the sheath. CONCLUSIONS: Clot amounts up to 171 g were removed quickly and completely by using these large-caliber balloon sheaths. Fluid loss from aspiration was negligible. Balloon occlusion prevented embolization of thrombus fragments proximal to the sheath. Further studies are needed to prove the efficacy of this technique in vivo.

Catheterization↗

PubMed2000

Reduction of contrast material dose and artifacts by a saline flush using a double power injector in helical CT of the thorax.

OBJECTIVE: Our objective was to evaluate a combined method of contrast material bolus followed by saline solution flush for thoracic helical CT and statistical comparison with a uniphasic injection protocol. MATERIALS AND METHODS: Fifty patients underwent helical CT of the thorax using 60 ml of contrast material (370 mg I/ml) followed by flushing with 30 ml of physiologic saline solution. These 50 patients had been examined before using our previous protocol, 75 ml of the same contrast material without a subsequent saline solution. Mean attenuation values for both protocols were measured in the superior vena cava, the pulmonary trunk, and the ascending aorta. Image artifacts and mediastinal and hilar depiction were graded and compared. RESULTS: Mean attenuation values in the superior vena cava were considerably higher in the regimen without saline solution flush (459 H versus 352 H) and in the pulmonary trunk and the ascending aorta were almost identical for both protocols. Injection of saline solution diminished surrounding artifacts (p = 0.001). Grading results for the evaluation of mediastinal and hilar structures were not significantly different in the two protocols (p = 0.564). CONCLUSION: Injection of contrast material followed by a saline solution bolus using a double power injector when performing thoracic helical CT allows a 20% reduction of contrast material volume to 60 ml with a similar degree of enhancement. In addition, perivenous artifacts in the superior vena cava are significantly reduced.

Adult↗