Accessory renal artery stenosis and hypertension: are these correlated? Evaluation using multidetector-row computed tomographic angiography

Background: Renal artery stenosis may produce hypertension, and this condition is referred to as renovascular hypertension (RVH).

Purpose: To evaluate, by using multidetector-row spiral computed tomographic angiography (MDCTA), whether a relationship between accessory renal artery stenosis and hypertension may be hypothesized.

Material and Methods: 214 patients (142 males, 72 females; mean age 66 years) who had previously undergone an MDCTA to study the abdominal vasculature were retrospectively studied. Patients with renal artery stenosis (RAS) were excluded from this analysis. The patients were studied by means of a four-detector-row CT, and scans were obtained after intravenous bolus administration of 110-140 ml of a nonionic contrast material with a 3-6 ml/s flow rate. As a second step, by means of statistical analysis, hypertension data were compared with findings of accessory artery stenosis. Two radiologists first independently reviewed the MDCTA images and then, in case of disagreement, in consensus. Interobserver agreement was calculated for all measurements.

Results: The overall number of detected accessory renal arteries was 74 in 56 of the 214 patients. Accessory renal artery stenosis was detected in 21 of the 56 patients. There was a difference in the prevalence of hypertension between patients with (n = 21) and without (n = 35) accessory renal artery stenosis (P = 0.0187). Interobserver agreement was good (kappa value 0.733).

Conclusion: Any statistical association between the presence of accessory renal artery stenosis and hypertension could not be disclosed. However, accessory renal artery stenosis, detected by MDCTA, is an important pathological sign that the radiologist has to assess in the light of its possible association with hypertension.     

Technical optimization of four-channel multidetector-row helical computed tomography for depicting arterial stenosis: a phantom study

Purpose: To determine the effects of detector configuration, as well as vessel orientation, on the depiction accuracy of arterial stenosis using four-channel multidetector-row helical computed tomography (MDCT) angiography in vitro.

Material and Methods: Five acrylic vessel phantoms (3 mm in diameter with 25 or 50% stenosis, or 5 mm with 25, 50, or 75% stenosis) were scanned with a four-channel MDCT scanner at five vessel orientations (0, 30, 45, 60, and 90° to the z-axis) using 4×1.25, 2.5, 3.75, and 5.0-mm detector configurations at beam pitches of 0.75 and 1.5. The percentage of stenosis was calculated by the ratio of the full width at half maximum for stenotic and non-stenotic portions of the phantom, and compared to the actual known values.

Results: A detector configuration of 4×1.25 mm provided good reproducibility, as well as high accuracy for assessing vessel stenosis, while a 4×2.5-mm or wider detector configuration caused underestimations of stenosis. Although the phantoms perpendicular to the z-axis were underestimated, the errors were kept in clinically acceptable ranges using the 4×1.25-mm detector configuration.

Conclusion: Four-channel MDCT accurately discerns stenosis for vessel phantoms of 3 or 5 mm in diameter at any orientation when using a detector configuration of 4×1.25 mm.     

Renal artery aneurysm: diagnosis and surveillance with multidetector-row computed tomography

Purpose: To investigate the prevalence of renal artery aneurysms, and to assess the value of multidetector-row computed tomography (MDCT) in diagnosing renal artery aneurysms.

Material and Methods: Altogether, 862 patients underwent arterial-phase contrast-enhanced CT scan of the abdomen in the period November 2003 to October 2005. A search for renal artery aneurysms was performed in our reporting system and revealed six patients with renal artery aneurysm (RAA).

Results: The incidence of RAA was 0.7%. All renal artery aneurysms were solitary, located in the main trunk or the first branch of the renal artery, with sizes from 1.5 cm to 3.4 cm. Five aneurysms were saccular, one fusiform. No underlying thrombosis was seen. Extensive calcification was found in one aneurysm. Three aneurysms were diagnosed using axial images, while three aneurysms were only displayed by volume rendering and maximum-intensity projection images.

Conclusion: This study demonstrates a 0.7% incidence of renal artery aneurysms in a total of 862 patients. MDCT has an important role in detecting and assessing renal artery aneurysms. Some aneurysms can only be displayed by post-processing techniques such as volume rendering and maximum-intensity projection.     

Impact of extended written information on patient anxiety and image motion artifacts during magnetic resonance imaging

Purpose: To evaluate whether increased written information to patients prior to magnetic resonance imaging (MRI) decreases patient anxiety and image motion artifacts.

Material and Methods: A two-group controlled experimental design was used. Of 242 patients, 118 received routinely given basic written information (control group) while 124 were given increased written information (intervention group). To measure patient anxiety before and during scanning, the self-report psychometric test State-Trait Anxiety Inventory (STAI) was used. After MR examination, the patients answered a questionnaire on satisfaction with the written information. The images were assessed with regard to motion artifacts.

Results: Motion artifacts were present in fewer patient images in the intervention group than in the control group (4.0% versus 15.4%; P = 0.003). There was no significant difference between the control and the intervention group regarding patient anxiety and satisfaction with the information. Women in both groups showed a higher level of anxiety than the men did.

Conclusion: Increased information about the MRI scanning procedure and expected experiences during the scan may help patients to lie still during the sequences, with a decrease in motion artifacts. However, further research is needed to evaluate the effect of other interventions on patient anxiety during MRI scanning.     

Preliminary study of hemodynamics in human carotid bifurcation by computational fluid dynamics combined with magnetic resonance angiography

Background: A longstanding hypothesis that correlates fluid dynamic forces and atherosclerotic disease has led to numerous analytical, numerical, and experimental studies over the years because it is very difficult to measure the hemodynamic variables of blood in vivo.

Purpose: To investigate the technique of visualization and quantitation of hemodynamic variables at carotid artery bifurcation in vivo by combining computational fluid dynamics (CFD) and vascular imaging.

Material and Methods: Twenty-six healthy volunteers underwent magnetic resonance (MR) angiography of the bilateral carotid artery by a 3.0T whole-body scanner. Hemodynamic variables at these carotid bifurcations were calculated and visualized by combining vascular imaging post-processing and CFD.

Results: The average velocity of the carotid bifurcation in the systolic phase and the diastolic phase was 0.46±0.24 m/s and 0.23±0.05 m/s, respectively. Eddy current and back flows were observed at bifurcation and the lateral part of the proximal internal carotid arteries (ICA) and external carotid arteries (ECA), and the shapes of them changed with phases of the cardiac cycle, which were significant at the middle of the systolic phase and faded out quickly downstream of the ICA and ECA. The average range of wall shear stress (WSS) at the bifurcation was 4.36±1.32 Pa, and the maximum WSS was 18.02±4.11 Pa. The WSS map revealed a large region of low WSS at the carotid bulb and extended to the outer wall in the proximal end of the ICA (the lowest value was below 0.5 Pa), and there was also a small region of low WSS at the outer wall in the proximal end of the ECA.

Conclusion: CFD combined with vascular imaging can calculate and visualize hemodynamic variables at carotid bifurcation in vivo individually.     

High-resolution computed tomography with single-slice computed tomography and 16-channel multidetector computed tomography: a comparison regarding visibility and motion artifacts

Background: High-resolution computed tomography is the image procedure of choice in the evaluation of interstitial lung disease. Multidetector-row computed tomography provides the possibility of simultaneous reconstruction of thin and thick slices from the same raw data, acquired from one single series. Thus, it may be tempting to exclude the step-and-shoot series.

Purpose: To compare high-resolution computed tomography (HRCT step-and-shoot) from single-slice CT (SSCT) and 16-channel multidetector CT (MDCT) in terms of visibility and motion artifacts, and to investigate whether thin images reconstructed from helical MDCT are equal to or better than conventional HRCT by SSCT in terms of visibility and motion artifacts.

Material and Methods: 20 patients underwent HRCT step-and-shoot by SSCT (SSCT step-and-shoot) and MDCT (MDCT step-and-shoot), and a helical MDCT acquisition (MDCT helical). Images from four anatomical levels were analyzed in random order regarding visibility and motion artifacts.

Results: Visibility using MDCT step-and-shoot was significantly better than or equal to SSCT step-and-shoot for segmental bronchi and fissures, but not for subsegmental bronchi. For MDCT helical, visibility was equal to or better than SSCT step-and-shoot for segmental bronchi, but not for fissures and subsegmental bronchi. Concerning motion artifacts, MDCT step-and-shoot and MDCT helical were significantly better than or equal to SSCT step-and-shoot.

Conclusion: The image quality (accounting for motion artifacts and visibility) of SSCT step-and-shoot and MDCT step-and-shoot is comparable. The visibility of anatomic structures in images from MDCT helical is inferior to HRCT step-and-shoot.     

What are radiologists doing to prevent contrast-induced nephropathy (CIN) compared with measures supported by current evidence? A survey of European radiologists on CIN associated with computed tomography

Background: Contrast-induced nephropathy (CIN) is a serious complication of the use of iodinated contrast media (CM), and is associated with increased morbidity and mortality.

Purpose: To investigate whether radiologists take sufficient measures to prevent CIN in computed tomography (CT).

Material and Methods: 2005 survey of 509 European radiologists who had ≥3 years' experience and performed ≥50 CT scans/week.

Results: The most common methods used to identify patients at risk of CIN were renal function measurements (64%), clinical judgment (55%), and patient questionnaires (31%); 9% made no routine attempt to identify at-risk patients. The most common preventive protocols used in at-risk patients included: intravenous (i.v.) saline volume repletion (59%) or oral hydration (52%) before/after CT; use of low-osmolar CM (LOCM; 40%) or isosmolar CM (IOCM; 36%); and N-acetylcysteine (20%); 8% used no hydration regimen. While 78% of respondents used ≤100 ml of CM in high-risk patients, 14% used ≤150 ml, and 9% set no volume limit. For 57% of respondents, osmolality was the most important attribute in choosing an iodinated CM in at-risk patients; 41% agreed that CIN risk is lower with IOCM versus LOCM (31% disagreed).

Conclusion: A European radiologist survey identified a need for increased implementation of evidence-based protocols to improve CIN prevention: routine identification of at-risk patients; withdrawal of nephrotoxic drugs; use of volume repletion regimens; lowest possible volume of CM; and appropriate CM.     

A new computed tomography-based radiographic method to detect early loosening of total wrist implants

Background: Diagnosis of loosening of total wrist implants is usually late using routine radiographs. Switching modality to computed tomography (CT) should aid in early diagnosis.

Purpose: To propose and evaluate the accuracy of a new CT method for assessing loosening of the carpal component in total wrist arthroplasty.

Material and Methods: A protocol encompassing volume registration of paired CT scans of patients with unexplained pain in a prosthetically replaced wrist (used in clinical routine) is presented. Scans are acquired as a dynamic examination under torsional load. Using volume registration, the carpal component of the prosthesis is brought into spatial alignment. After registration, prosthetic loosening is diagnosed by a shift in position of the bones relative to the prosthesis. This study is a preclinical validation of this method using a human cadaverous arm with a cemented total wrist implant and tantalum markers. Seven CT scans of the arm were acquired. The scans were combined into 21 pairs of CT volumes. The carpal component was registered in each scan pair, and the residual mismatch of the surrounding tantalum markers and bone was analyzed both visually and numerically.

Results: The detection limit for prosthetic movement was less than 1 mm.

Conclusion: The results of this study demonstrate that CT volume registration holds promise to improve detection of movement of the carpal component at an earlier stage than is obtainable with plain radiography.     

A three-dimensional laminated paper model of the scaphoid from computed tomography

Purpose: To describe a method of producing a life-sized three-dimensional (3D) solid model of a scaphoid bone by combining multidetector-row computed tomography (MDCT) volume data and rapid prototyping technique using thin paper as material, and to evaluate the dimensional accuracy of the experimental model.

Material and Methods: We experimentally produced life-sized 3D solid models of 14 cadavers' scaphoid bones using high-resolution MDCT volume data, and evaluated the dimensional accuracy of the 3D solid models.

Results: The 3D solid model was almost perfectly produced in both size and shape (length, height, width, dorsal cortical angle, and landmarks of the scaphoid bone) compared to the real cadaver's scaphoid bone. In addition to accuracy, the cost and time for creating the model might be reasonable.

Conclusion: This technique may be useful in assisting repair of scaphoid bone fracture.     

Diffusion-weighted magnetic resonance imaging of cerebrospinal fluid in patients with and without communicating hydrocephalus

Background: Recent concepts about cerebrospinal fluid (CSF) circulation in communicating hydrocephalus (CoHy), which is also termed “restricted arterial pulsation hydrocephalus,” suggest reduced arterial pulsations of subarachnoid vessels with a smaller amount of CSF shifted in subarachnoid spaces during the early systole. The postulated restriction of subarachnoid arterial pulsations in CoHy should induce a smaller motion artifact and reduced local stream effects in CSF in magnetic resonance (MR) diffusion-weighted imaging (DWI).

Purpose: To investigate the maximum diffusivity in CSF in patients with and without CoHy using DWI.

Material and Methods: 12 patients without CSF circulation disturbances and six cases with proven CoHy were assessed. Diffusion was measured in six noncollinear directions without triggering the arterial pulse wave (scan time 6:45 min, voxel size 2×2×2 mm). Due to expected artifacts, the calculated maximum diffusivity was called apparent diffusivity. Regional high and low apparent diffusivity was assessed in CSF spaces on newly created 3D CSF motion maps.

Results: Patients with regular CSF circulation exhibited high apparent diffusivity in CSF in basal subarachnoid spaces, whereas apparent diffusivity was low there in patients with CoHy.

Conclusion: DWI opens a feasible approach to study CSF motion in the neurocranium. Restricted arterial pulsations seem to be involved in CoHy.     

Is subcutaneous local anesthesia in shoulder magnetic resonance arthrography necessary?

Background: Magnetic resonance arthrography is a well-established diagnostic method in degenerative and traumatic disorders of the shoulder. Some radiologists prefer to apply a local anesthetic to the skin prior to performing the joint puncture. However, no information regarding the efficacy of local anesthetics exists.

Purpose: To assess patient discomfort in arthrography injection.

Material and Methods: A patient survey (n = 74) utilizing a visual analog scale (VAS) measured the intensity of pain in arthrography injection by those receiving local anesthetics (n = 36) versus those who did not (n = 38).

Results: Mean VAS scores were 20.8 (median 10.5, SD 24.3) for those receiving local anesthetics versus 19.3 (median 13.0, SD 20.7) for those who did not (P = 0.83, Mann-Whitney U test).

Conclusion: Routine use of local anesthesia of the skin in arthrography injection is unnecessary.     

Statin-treated familial hypercholesterolemia patients with coronary heart disease and pronounced atherosclerosis do not have more brain lesions than healthy controls in later middle age

Background: Clinically silent brain lesions detected with magnetic resonance imaging (MRI) are associated with increased risk for stroke, while stroke risk is controversial in familial hypercholesterolemia (FH).

Purpose: To determine whether the occurrence and size of clinically silent brain lesions in FH patients with coronary heart disease (CHD) is higher than in neurologically healthy controls without CHD.

Material and Methods: Brain MRI (1.5T) was performed on 19 DNA-test-verified FH patients with CHD and on 29 cardiovascularly and neurologically healthy controls, all aged 48 to 64 years. All patients were on cardiovascular medication. Intracranial arteries were evaluated by MR angiography. Infarcts, including lacunas, and white matter T2 hyperintensities (WMHI), considered as signs of small vessel disease, were recorded. A venous blood sample was obtained for assessment of risk factors. Carotid and femoral intima-media thicknesses (IMT), assessed with ultrasound, were indicators of overall atherosclerosis.

Results: On intracranial MR angiography, three patients showed irregular walls or narrowed lumens in intracranial carotid arteries. No silent infarcts appeared, and no differences in numbers or sizes of WMHIs between groups were recorded. Patients had greater carotid and femoral IMTs, and a greater number of carotid and femoral plaques. Cholesterol-years score, level of low-density lipoprotein (LDL) cholesterol, and level of high-sensitivity C-reactive protein (hsCRP) of the FH-North Karelia patients were higher than those of the controls, while the level of high-density lipoprotein (HDL) cholesterol in controls was higher.

Conclusion: FH patients with CHD and adequate cardiovascular risk-factor treatment showed no difference in the amount or size of clinically silent brain lesions compared to controls, despite patients' more severe atherosclerosis.     

Low-field magnetic resonance imaging of the lumbar spine: reliability of qualitative evaluation of disc and muscle parameters

Purpose: To determine the intra- and interobserver reliability in grading disc and muscle parameters using low-field magnetic resonance imaging (MRI).

Material and Methods: MRI scans of 100 subjects representative of the general population were evaluated blindly by two radiologists. Criteria for grading lumbar discs were based on the spinal nomenclature of the Combined Task Force and the literature. Consensus in rating was achieved by evaluating 50 MRI examinations in tandem. The remaining 50 examinations were evaluated independently by the observers to determine interobserver agreement and re-evaluated by one of the observers to determine intra-observer agreement.

Results: Intra- and interobserver agreement was substantial when grading changes in the lumbar discs. Interobserver agreement was fair to moderate in grading the lumbar muscles, whereas intra-observer agreement was almost perfect.

Conclusion: Convincing reliability was found in the evaluation of disc- and muscle-related MRI variables.     

Determination of the effect of a single hemodialysis session on retrobulbar blood hemodynamics by color Doppler ultrasonography

Background: Retrobulbar hemodynamic alterations can occur during hemodialysis sessions, and patients with chronic renal failure may experience visual problems.

Purpose: To evaluate the effect of single-session hemodialysis on retrobulbar vessel hemodynamics by color Doppler ultrasonography.

Material and Methods: Thirty-five patients were included in the study. Retrobulbar blood flows were examined before and after dialysis sessions. Doppler spectral patterns of retrobulbar blood flow were evaluated. The t test for paired samples and the Wilcoxon matched-pairs signed-rank test were used for comparing the flow values before and after dialysis.

Results: Systolic and diastolic blood flow velocities of the ophthalmic artery, central retinal artery, central retinal vein, nasal posterior ciliary artery, and temporal posterior ciliary artery were found to be decreased bilaterally after hemodialysis sessions. No significant change was observed in resistivity index values after hemodialysis sessions.

Conclusion: Our findings reveal that retrobulbar circulation was disturbed after a single hemodialysis session.     

Assessing doses to interventional radiologists using a personal dosimeter worn over a protective apron

Backround: Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure.

Purpose: To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists.

Material and Methods: Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters).

Results: Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose.

Conclusion: A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron.     

Evaluation of coronary bypass graft occlusion and stenosis with 64-detector-row computed tomography angiography

Background: A noninvasive imaging modality is desirable for the evaluation of coronary bypass graft stenosis and occlusion.

Purpose: To prospectively evaluate the effectiveness of 64-detector-row computed tomography (DCT) for the assessment of coronary bypass grafts.

Material and Methods: Forty-two patients (35 male, seven female, mean age 66.3 years) with 103 bypass grafts (32 arterial, 71 venous) were examined with 64-DCT. The evaluations were done by two radiologists blinded to the results of quantitative coronary angiography (QCA), used as the reference standard.

Results: All of the 26 occluded grafts, nine of the 10 stenosed grafts, and 66 of the 67 patent grafts were correctly diagnosed with 64-DCT angiography. The sensitivity, specificity, and positive and negative predictive values for 64-DCT in detecting graft stenosis were 90%, 99%, 90%, and 99%, respectively. For graft occlusion, all were 100%. No statistically significant difference was found between 64-DCT and QCA for the evaluation of bypass grafts. Intermodality and interobserver agreement were excellent.

Conclusion: 64-DCT angiography is a reliable, noninvasive diagnostic method for the assessment of coronary bypass grafts. It can be considered as a useful tool for follow-up purposes and may function as a gatekeeper before invasive procedures.     

Reliability of the evaluation of multidetector computed tomography images from the scanner's console in high-energy blunt-trauma patients

Purpose: To evaluate the reliability of a structured 5-min evaluation of multidetector computed tomography (MDCT) images from the scanner's console in high-energy trauma patients.

Material and Methods: Forty patients were scanned with four-slice MDCT using a standardized trauma protocol. Image evaluation covered the thorax, abdomen, and pelvis. The radiologist scrolled axial images on the scanner's console using three different window settings (lung, soft tissue, and bone) and performed a prospective structured evaluation of the traumatic lesions. The findings were compared to the final radiological diagnosis of the MDCT data made on a PACS workstation, the operative findings, and the clinical follow-up.

Results: Evaluation from the scanner's console enabled the diagnosis of all potential life-threatening injuries, the sensitivity for all injuries being 60% and specificity 98%.

Conclusion: A PACS workstation is needed for the final diagnosis of all injuries, but this rapid screening method can reliably detect all injuries that require instant care.     

Imaging of four-corner fusion (SLAC arthrodesis) of the wrist with 64-slice computed tomography

Purpose: To find out whether it is possible to evaluate the healing of wrist arthrodesis, carried out with a metallic spider plate, by means of 64-slice computed tomography (CT).

Material and Methods: 18 CT examinations were performed in 12 patients 2 weeks to 37 months following scapholunate advanced collapse (SLAC) arthrodesis fixed with a metallic plate. Ten patients also had plain films of the wrist. Radiation doses were estimated.

Results: Plain films were difficult to evaluate due to overprojection of the spider plate. With 64-slice CT, however, it was possible to evaluate the healing process in all patients in spite of metallic artifacts. Radiation doses were low.

Conclusion: The healing of SLAC arthrodesis of the wrist is difficult to evaluate with conventional radiography due to the metallic plate. By means of 64-slice CT, however, it was possible to “see under” the plate in all 12 patients.     

Ultrasound guidance for puncture and injection in the radiocarpal joint

Background: The use of intra-articular contrast agent has been shown to increase the diagnostic accuracy of wrist magnetic resonance (MR) in patients with suspected trauma of the wrist ligaments. Traditionally, the contrast agent has been applied under fluoroscopic guidance.

Purpose: To present a method based on ultrasound guidance for the injection of intra-articular contrast agent in wrist MR.

Material and Methods: One hundred eight patients (56 female and 52 male, mean age 36 years) referred for wrist MR arthrograms due to suspected ligament rupture were included in this retrospective study. The preferred injection point is about 1 cm distal to Lister's tubercle in the distal radius. A correct positioning of the injection needle can be ensured using ultrasound guidance.

Results: Using this technique, the injection was intra-articular in 93.5% of the 108 injections over a 2-year learning period.

Conclusion: Ultrasound guidance of the contrast injection in radiocarpal MR arthrograms is a cost-effective and safe alternative to fluoroscopically guided procedures. Furthermore, the use of ultrasound guidance provides clues about possible fluid collections within the joint.     

Pediatric multidetector computed tomography using tube current modulation and a patient image gallery

Background: Dose reduction is crucial in pediatric multidetector computed tomography (MDCT).

Purpose: To perform pediatric 16-slice MDCT using tube current modulations and to adjust prospectively the tube current using a patient image gallery (IG) providing simulated dose-reduced protocols; and to evaluate and compare the image quality of the IG and the clinical MDCT.

Material and Methods: 30 examinations (thorax, n=15; abdomen, n=8; pelvis, n=7) in 20 patients (nine male, age 8.05±7.33 years, weight 29.8±24.02 kg) were performed according to an IG on a 16-slice MDCT with additional use of online tube current modulation (CARE Dose). Three radiologists visually assessed image quality from the IG and actual 16-slice MDCT scans. For objective analysis, image noise was determined.

Results: Statistical analysis showed moderate concordance in objective (K =0.68-0.78) and subjective (K =0.33-0.64) image assessment between the IG and clinical 16-slice MDCT scans. Depending on the weight group and clinical question, no or only minor dose reductions in the chest, but moderate to considerable reductions in the abdominal/pelvic 16-slice MDCT scans compared to previously used pediatric protocols were achieved. Extra dose reduction was achieved due to additional use of CARE Dose depending on age group and scan region (mean 8.6-23.9%).

Conclusion: The IG enabled us to prospectively reduce the tube current and adapt the required image quality to the clinical question. Additional dose reduction was achieved with application of CARE Dose; nevertheless, the images are comparable to the simulated images of the IG.