Adequacy of an early arterial phase low-volume contrast protocol in 64-detector computed tomography angiography for aortoiliac aneurysms

Article Outline

• Abstract
• Materials and methods
  • Patients
  • Scanning protocol
  • Quantitative analysis
  • Visual assessment
  • Statistical analysis
• Results
  • Aortoiliac enhancement
  • Visual assessment
• Discussion
• Conclusions
• Author contributions
• References
• Copyright

Purpose

This retrospective study was conducted to determine whether a low-volume contrast medium protocol provides sufficient enhancement for 64-detector computed tomography angiography (CTA) in patients with aortoiliac aneurysms.

Methods

Evaluated were 45 consecutive patients (6 women; mean age, 72 ± 6 years) who were referred for aortoiliac computed tomography angiography between October 2005 and January 2007. Group A (22 patients; creatinine clearance, 64.2 ± 8.1 mL/min) received 50 mL of the contrast agent. Group B (23 patients; creatinine clearance, 89.4 ± 7.3 mL/min) received 100 mL of the contrast agent. The injection rate was 3.5 mL/s, followed by 30 mL of saline at 3.5 mL/s. Studies were performed on the same 64-detector computed tomography scanner using a real-time bolus-tracking technique. Quantitative analysis was performed by determination of mean vascular attenuation at 10 regions of interest from the suprarenal aorta to the common femoral artery by one reader blinded to type and amount of contrast agent and compared using the Student t test. Image quality according to a 4-point scale was assessed in consensus by two readers blinded to type and amount of contrast medium and compared using the Mann-Whitney test. Multivariable adjustments were performed using ordinal regression analysis.

Results

Mean total attenuation did not differ significantly between both groups (196.5 ± 33.0 Hounsfield unit [HU] in group A and 203.1 ± 44.2 HU in group B; P = .57 by univariate and P > .05 by multivariable analysis). Accordingly, attenuation at each region of interest was not significantly different (P > .35). Image quality was excellent or good in all patients. No significant differences in visual assessment were found comparing both contrast medium protocols (P > .05 by univariate and by multivariable analysis).

Conclusions

Aortoiliac aneurysm imaging can be performed with substantially reduced amounts of contrast medium using 64-detector computed tomography angiography technology.

With the development of multidetector technology, computed tomography angiography (CTA) has evolved as one of the modalities of choice for aortoiliac imaging, particularly in the evaluation of aneurysmal disease.¹, ², ³ In contrast with open surgical abdominal aortic aneurysm (AAA) repair, endovascular AAA repair (EVAR) requires precise preprocedural and follow-up imaging.⁴ Sufficient arterial enhancement is essential to precisely assess vascular anatomy in the surveillance of AAA, for planning before EVAR, and during follow-up. Improved arterial enhancement can be achieved by increases in the intravenous contrast medium (CM) iodine concentration, total CM volume administered, or rate of CM infusion.⁵ Thus, the use of high-concentration, high-volume, and rapid injection rate CM has been accepted in several CT applications to improve enhancement.⁵, ⁶, ⁷, ⁸, ⁹

Contrast nephropathy is a well-recognized complication of CM use.¹⁰, ¹¹, ¹² Among several other mainly noninfluenceable risk factors such as baseline renal function, diabetes mellitus, and patient age, the volume of CM given along with its concentration directly correlates with the risk of contrast nephropathy.¹⁰, ¹³, ¹⁴, ¹⁵ Chronic kidney disease is encountered in 7% to 25% of patients undergoing EVAR and, owing to the need for preprocedural and follow-up contrast-enhanced CTA imaging, is a potential limitation to the use of this minimally invasive treatment option.¹⁶, ¹⁷

With the recent introduction of 64-detector CT scanners, scan volumes can be imaged much faster, thus allowing protocols to thinly image the aortoiliac segment within a few seconds. As a result, scan optimization with the contrast bolus becomes more challenging. The shorter scanning time of the 64-detector CT scanner may enable a more efficient use of CM; therefore, the amount of CM injected may be reduced without decreasing contrast enhancement. The purpose of this study was to retrospectively determine whether a low-volume CM protocol provides sufficient enhancement and imaging quality for 64-detector CTA in patients with aortoiliac aneurysms.

Back to Article Outline

Materials and methods 

Patients 

We studied 45 patients (6 women), with a mean age 72 ± 6 years, who had undergone aortoiliac CTA at our institution. Institutional Review Board approval for retrospective data review for this study was obtained. Between October 2005 and January 2007, 22 patients (group A) underwent CTA with a reduced CM volume of 50 mL. These were compared with 23 consecutive patients (group B) who had undergone CTA with our standard protocol of 100 mL of CM on the same 64-detector scanner during the same period of time. Patients had been examined clinically between 1 and 2 weeks after CTA had been performed but had not undergone routine laboratory screening for renal function. Patient baseline characteristics are outlined in Table I. After EVAR, 22 patients were analyzed, consisting of 10 patients in group A and 12 in group B.

Table I. Patient baseline characteristics

Characteristic	Group A (n = 22)a	Group B (n = 23)b	P
Age, mean ± SD years	72±6	72±6	.54c
Female sex, No. (%)	3 (14)	3 (13%)	>.99d
AAA diameter, mean ± SD mm	49.8±11.5	53.6±12.6	.29c
Body weight, mean ± SD lb	165±27	177±22	.26c
Creatinine clearance, mean ± SD mL/min	64.2±8.1	89.4±7.3	.02c
Pre-EVAR, No. (%)	12 (55)	11 (48)	>.99d
Post-EVAR, No. (%)	10 (45)	12 (52)

EVAR, Endovascular aortic aneurysm repair.

Indication for use of the reduced CM protocol had been determined clinically by the referring interventionalist or monitoring radiologist in patients with impaired renal function according to earlier experiences with a reduced amount of contrast in patients undergoing CTA using 8-detector technology.¹⁸ Except for a decreased creatinine clearance in group A, patient baseline characteristics did not differ significantly between the groups.

Scanning protocol 

All CT scans were performed with a 64-detector CT scanner (Brilliance 64; Philips Medical Systems; Best, Netherlands). The CM was injected through an 18-gauge cannula in an antecubital vein using a power injector (Envision, Medrad, Pittsburgh, Pa). The following CM types were used: Optiray 320 (Ioversol, Mallinckrodt, Hazelwood, Mo; iodine, 320 mg/mL; viscosity at 37°C, 5.8 cps) in 24 patients, Visipaque 320 (Iodixanol, Amersham Health, Princeton, NJ; iodine, 320 mg/mL; viscosity at 37° C, 11.8 cps) in three, and Optiray 350 (Ioversol; iodine, 350 mg/mL; viscosity at 37° C, 9.0 cps) in 18. The CM injection rate was 3.5 mL/s and was followed with 30 mL of saline injected at 3.5 mL/s in all patients (Table II).

Table II. Injection protocol

The start of the scanning was triggered automatically by a real-time bolus tracking technique. A region of interest (ROI) in the proximal abdominal aorta was used to monitor the bolus. The scanning started 6 seconds after the enhancement of the ROI had crossed the 200 Hounsfield unit (HU) threshold trigger. Further data acquisition settings were 0.625 mm × 64 detectors, 140 KvP, 400 mA, reconstructed at 2-mm thickness every 1 mm. The 100-mL protocol (group B, Fig 1) used a 1-second rotation time, pitch of 0.89, for an average 14-second scan time. The 50-mL CM protocol (group A, Fig 2) used a 0.75-second rotation time, pitch of 0.89, decreasing the average scan time to 10 seconds. Delayed images were performed in post-EVAR patients using the same imaging settings 30 seconds after completion of the arterial phase images.

• 
  • View Large Image
  • Download to PowerPoint

• Fig 1. 

  Representative 64-detector computed tomography image with 100 mL of contrast medium in a 72-year-old man with a 55-mm abdominal aortic aneurysm. A, Transverse image shows the infrarenal aortic aneurysm at its widest transverse diameter. Arterial attenuation, 201.5 HU. B, Sagittal reconstruction shows the infrarenal aorta and common iliac artery with adequate arterial enhancement along the aortoiliac segment.

• 
  • View Large Image
  • Download to PowerPoint

• Fig 2. 

  Representative 64-detector computed tomography image using 50 mL of contrast medium in an 82-year-old woman with a 48-mm abdominal aortic aneurysm. A, Transverse image shows the infrarenal aortic aneurysm at its widest transverse diameter. Arterial attenuation, 195.7 HU. B, A reconstructed sagittal view shows the infrarenal aorta and common iliac artery with adequate arterial enhancement along the aortoiliac segment.

Quantitative analysis 

Contrast-enhanced CTA images during the arterial phase were displayed on a picture archiving and communication system (PACS) workstation (Philips Medical Systems, Best, the Netherlands) in a randomized order and interpreted by an endovascular interventionist (N. D.) with a special interest in aortic CT and 7 years of experience in vascular imaging who was blinded to type and amount of CM.

The magnitude and uniformity of arterial enhancement was measured using circular ROIs in the arterial center along the abdominal aortic z-axis at seven different ROIs.¹⁸, ¹⁹, ²⁰ An attempt was made to select a ROI area containing as much of the intravascular segment as possible but not so large that it approached the partly calcified edges of the vessel. The suprarenal aorta (ROI 1) was defined as the first CT slice above the highest renal artery. The left renal artery (ROI 2a) and right renal artery (ROI 2b) were defined as the axial CT slice with best depiction of the renal artery. The infrarenal aortic neck (ROI 3) was defined as the first CT slice below the lowermost renal artery. The maximally dilated AAA sac (ROI 4) was defined as the contrast-enhanced aortic flow channel at the level of maximal AAA dilatation. In post-EVAR patients, attenuation values were measured within the graft. In case the maximally dilated sac was located at the level of both graft limbs, attenuation values were measured in both graft limbs and values were averaged.

The aortic bifurcation level (ROI 5) was defined as the first CT slice above the aortic bifurcation. In post-EVAR patients, attenuation values were measured in both graft limbs and values were averaged. The distal common iliac artery (ROI 6a, left; ROI 6b, right) was defined as the common iliac artery on the first slice above the iliac bifurcation. The proximal common femoral artery (ROI 7a, left; ROI 7b, right) was defined as the common femoral artery on the first slice above the femoral bifurcation.

Visual assessment 

The axial, sagittal, and reformatted coronal and volume-rendered images were displayed on a PACS workstation and evaluated in a randomized order on a consensus basis by a diagnostic and interventional radiologist with 8 years experience in aortic imaging (C. P.) and an endovascular interventionist with a special interest in aortic CT and 7 years of experience in vascular imaging (N. D.) who were blinded to the volume of CM used.

Images were analyzed at the previously specified abdominal aortic ROIs. The following 4-point scale²¹, ²², ²³ was used for assessment of overall image quality and visual depiction of arterial landmarks defined as ROIs 1 to 7 as well as for analysis of the quality of intraprosthesis vs extraprosthesis enhancement: 1 = excellent; 2 = good; 3 = sufficient; and 4 = poor. Accordingly, the quality of intraprosthesis vs extraprosthesis enhancement was assessed on delayed CTA images. Special care was taken to assess the presence of endoleaks in post-EVAR patients on delayed CTA images. If the readers disagreed on the quality of the image, the worse category was assumed. Special care was taken to assess the presence of endoleaks in post-EVAR patients on delayed CTA images.

Statistical analysis 

Continuous variables are presented as mean ± standard deviation (SD). Categoric data are given as counts and percentages. All statistical analyses were performed using SPSS 12.0.1 statistical software (SPSS Inc, Chicago, Ill). The Student t test was used to compare aortoiliac attenuation between the two patient groups after positive assessment for normal distribution of continuous data. To compare the uniformity of the contrast column, we calculated the difference between the maximum and minimum attenuation values along the z-axis for each patient. The Mann-Whitney test was used to verify visual estimation results. Multivariable linear regression analysis was performed to assess the association between viscosity, iodine concentration, and amount of CM with results from visual assessment and quantitative analysis. A value of P < .05 was considered statistically significant.

Back to Article Outline

Results 

Computed tomography imaging was accomplished without adverse events in all patients. Endoleaks were diagnosed on 2 of 12 (17%) delayed post-EVAR CTA scans in the 100-mL CM group in patients exhibiting AAA sac expansion, whereas no post-EVAR CTA scan from the 50-mL CM group showed AAA sac expansion or enhancement outside the aortic endograft. In the first patient, a type Ia endoleak was confirmed on a further CT scan 1 month later using 100-mL of CM, and in the second patient, a type II endoleak had been diagnosed 6 months before the CT was analyzed and was further confirmed during an AAA sac injection and embolization procedure.

Aortoiliac enhancement 

No significant differences in attenuation were noted comparing the single ROIs between the groups (P > .35, Table III, Fig 3). The mean total attenuation of the aortoiliac segment was 203.1 ± 44.2 HU in group A and 196.5 ± 33.0 HU in group B (P > .57, Table III). The mean difference between the maximum and minimum attenuation values along the z-axis did not differ significantly between group A and group B, indicating the presence of a uniform contrast column for CTA performed with both CM protocols (P = .38, Table III). Multivariable linear regression analysis adjusted for viscosity, iodine concentration, and amount of CM confirmed that none of these factors independently influenced aortoiliac attenuation of all ROIs analyzed (P > .05).

Table III. Comparison of mean attenuation between patients undergoing computed tomography angiography using 50 mL vs 100 mL contrast medium

CM, Contrast medium.

• 
  • View Large Image
  • Download to PowerPoint

• Fig 3. 

  Mean attenuation ± SD along the aortoiliac z-axis for group A, which received 50 mL of contrast material (circle, solid line), and for group B, which received 100 mL of contrast material (square, dotted line). The graph shows constant arterial enhancement along the aortoiliac z-axis for both protocols (P > .05). ROI, Region of interest.

Visual assessment 

Contrast-enhanced aortoiliac CTA was graded as excellent or good in all patients (Table IV). No significant differences in visual CTA assessment were found when the two CM protocols (P > .05) were compared. Multivariable linear regression analysis adjusted for viscosity, iodine concentration, and amount of CM confirmed that none of these factors independently influenced visual assessment results (P > .05).

Table IV. Visual assessment results

CM, contrast material; ROI, region of interest.

Back to Article Outline

Discussion 

Contrast medium–enhanced examinations are the third leading cause of hospital-acquired acute renal failure,²⁴ and renal insufficiency is a significant limitation to the use of EVAR in medically frail AAA patients. Our study indicates that 64-detector CTA imaging in patients with aortoiliac aneurysms can be performed with substantially reduced CM volumes without sacrificing arterial attenuation and imaging quality. Thus, given the direct relationship of CM volume with the risk of contrast nephropathy,¹⁰, ¹³, ¹⁴, ¹⁵ findings from the present study may help to lower the risk of contrast nephropathy for AAA patients undergoing CTA and expand the applicability of CTA to patients with borderline renal function.

Adequate and uniform enhancement is essential in aortoiliac CTA imaging before and after EVAR. The most important factor affecting the magnitude of contrast enhancement achieved is the iodine flux; that is, the amount of iodine entering the circulation per unit of time, which in turn is influenced by the rate and volume of injection and the iodine concentration of the CM.⁵ By diminishing the volume of CM, a significant impact of total iodine administered can be effected.¹³, ¹⁴ A reduction of CM dose was shown to yield acceptable attenuation and imaging quality in aortoiliac CTA using a 16-detector scanner.²⁵ In that series, however, the CM dose was only reduced by <20%, resulting in the use of CM doses of 100 mL.²⁵ Accordingly, it has recently been shown that the amount of CM can be reduced when 64-detector technology is used in various other applications such as depiction of pulmonary²⁶ and coronary²⁷ arteries.

The present series, to our knowledge, is the first to investigate the effect of a reduced amount of CM on attenuation and depiction of aortoiliac anatomy using 64-detector technology. In our study, arterial attenuation values when the low-volume CM protocol (50 mL) was used were not quantitatively different from values obtained in patients undergoing CTA with the standard, higher-volume CM protocol. The advent of 64-detector CTA increased scanning speed and was associated with increased spatial resolution.⁹, ²⁸ Nevertheless, the degree of contrast enhancement achieved is directly proportional to the volume, rate, and concentration of iodine used.²⁹, ³⁰ Increased scanning speed necessitates an accurate synchronization of CT image acquisition with CM delivery and enables a more efficient use of CM. Thus, by using a shorter rotation time in patients receiving a reduced amount of CM in the present study, the contrast bolus could be followed faster, thereby decreasing CM volumes needed without affecting arterial attenuation. Furthermore, qualitative measurements in our study showed that image quality was excellent or good in both protocol groups. Hence, observations from the present series underline that the amount of CM can be further reduced without sacrificing image quality using 64-detector CTA.

The use of a saline flush after CM injection with a dual-head power injector can aid to decrease the total amount of CM required for optimal tissue enhancement by eliminating the dead space between the brachial vein and the superior vena cava. When flushing with saline solution, pooling of CM in the injection system and the arm veins is avoided. Several studies have shown the potential of a saline solution flush in CM dose reduction in multi-slice CTA in various arterial segments.¹⁹, ³¹, ³²

There are limitations to our study. First, this was a retrospective and nonrandomized study. For this reason, not all patient baseline factors that affect cardiac output could be systematically assessed. Important patient characteristics such as body weight and AAA size were similar, however, and the different types of CM used were distributed equally in both groups. We also performed multivariable linear regression analysis adjusted for potentially confounding factors.

Second, the mean AAA diameter in patients from the present series was not excessively large. Our study therefore does not allow for a dedicated subgroup analysis of imaging quality in patients with very large AAA in whom administration of a lower CM dose might potentially lead to a decrease in attenuation and imaging quality due to slower flow situations.

Third, the present series contained only two patients with endoleaks in the group that underwent CTA with the standard volume of CM and did not allow for a comparison with a reference standard imaging method. However, all patients from the reduced CM group exhibited AAA shrinkage, and visual assessment revealed a good to excellent differentiation of intragraft vs AAA sac enhancement in all delayed CTA images of post-EVAR patients, indicating a high probability of endoleak detection with either protocol. Thus, it cannot be entirely ruled out that the absence of endoleak visualization could be due to an absence of endoleak, to inadequate timing, or to reduced volume of contrast administered.

Fourth, this retrospective series contained three types of CM that differed slightly with regard to viscosity and concentration. As shown within a multivariable regression analysis, these potentially confounding factors did not influence visual analysis or arterial attenuation. Of interest is that others have previously made similar observations with regard to attenuation and the specific iodine concentrations used in the present series.³³

Finally, our study, unfortunately, was not designed to elucidate the effect of lower contrast volume studies on renal function after imaging.

Back to Article Outline

Conclusions 

A 64-detector CTA protocol that uses half the amount of CM compared with the standard protocol provides uniform attenuation and excellent visual depiction of the anatomic details in aortoiliac imaging. Given the direct relationship of CM exposure and contrast nephropathy,¹³, ¹⁴ and considering the need for repeated CTA imaging in AAA patients,³⁴ a reduction in the volume of CM may offer improved imaging options in AAA patients with borderline renal function and renal insufficiency. Moreover, a reduction of CM volumes has the potential to decrease costs of routine CTA. Further research is warranted to prospectively assess the ability of the present low-volume CM protocol in depiction of endoleaks and prevention of contrast nephropathy.

Back to Article Outline

Author contributions 

Back to Article Outline

References 

1. Rubin GD. MDCT imaging of the aorta and peripheral vessels. Eur J Radiol. 2003;45(suppl 1):S42–S49
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (119 KB)
   • CrossRef
2. Armerding MD, Rubin GD, Beaulieu CF, Slonim SM, Olcott EW, Samuels SL, et al. Aortic aneurysmal disease: assessment of stent-graft treatment-CT versus conventional angiography. Radiology. 2000;215:138–146
   • View In Article
   • MEDLINE
3. Diehm N, Herrmann P, Dinkel HP. Multidetector CT angiography versus digital subtraction angiography for aortoiliac length measurements prior to endovascular AAA repair. J Endovasc Ther. 2004;11:527–534
   • View In Article
   • MEDLINE
   • CrossRef
4. Beebe HG, Kritpracha B. Computed tomography scanning for endograft planning: evolving toward three-dimensional, single source imaging. Semin Vasc Surg. 2004;17:126–134
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (494 KB)
   • CrossRef
5. Brink JA. Use of high concentration contrast media (HCCM): principles and rationale–body CT. Eur J Radiol. 2003;45(suppl 1):S53–S58
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (234 KB)
   • CrossRef
6. Costello P, Dupuy DE, Ecker CP, Tello R. Spiral CT of the thorax with reduced volume of contrast material: a comparative study. Radiology. 1992;183:663–666
   • View In Article
   • MEDLINE
7. Cascade PN, Gross BH, Kazerooni EA, Quint LE, Francis IR, Strawderman M, et al. Variability in the detection of enlarged mediastinal lymph nodes in staging lung cancer: a comparison of contrast-enhanced and unenhanced CT. AJR Am J Roentgenol. 1998;170:927–931
   • View In Article
   • MEDLINE
8. Furuta A, Ito K, Fujita T, Koike S, Shimizu A, Matsunaga N. Hepatic enhancement in multiphasic contrast-enhanced MDCT: comparison of high- and low-iodine-concentration contrast medium in same patients with chronic liver disease. AJR Am J Roentgenol. 2004;183:157–162
   • View In Article
   • MEDLINE
9. Diehm N, Kickuth R, Gahl B, Do DD, Schmidli J, Rattunde H, et al. Intraobserver and interobserver variability of 64-row computed tomography abdominal aortic aneurysm neck measurements. J Vasc Surg. 2007;45:263–268
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (206 KB)
   • CrossRef
10. Walsh SR, Tang T, Gaunt ME, Boyle JR. Contrast-induced nephropathy. J Endovasc Ther. 2007;14:92–100
    • View In Article
    • MEDLINE
    • CrossRef
11. Van Praet JT, De Vriese AS. Prevention of contrast-induced nephropathy: a critical review. Curr Opin Nephrol Hypertens. 2007;16:336–347
    • View In Article
    • MEDLINE
12. Nyman U, Almen T, Aspelin P, Hellstrom M, Kristiansson M, Sterner G. Contrast-medium-Induced nephropathy correlated to the ratio between dose in gram iodine and estimated GFR in mL/min. Acta Radiol. 2005;46:830–842
    • View In Article
    • MEDLINE
    • CrossRef
13. Manske CL, Sprafka JM, Strony JT, Wang Y. Contrast nephropathy in azotemic diabetic patients undergoing coronary angiography. Am J Med. 1990;89:615–620
    • View In Article
    • Abstract
    • Full-Text PDF (663 KB)
    • CrossRef
14. Rudnick MR, Goldfarb S, Wexler L, Ludbrook PA, Murphy MJ, Halpern EF, et al. Nephrotoxicity of ionic and nonionic contrast media in 1196 patients: a randomized trial (The Iohexol Cooperative Study). Kidney Int. 1995;47:254–261
    • View In Article
    • MEDLINE
    • CrossRef
15. Meschi M, Detrenis S, Musini S, Strada E, Savazzi G. Facts and fallacies concerning the prevention of contrast medium-induced nephropathy. Crit Care Med. 2006;34:2060–2068
    • View In Article
    • MEDLINE
    • CrossRef
16. Chuter TA, Reilly LM, Faruqi RM, Kerlan RB, Sawhney R, Canto CJ, et al. Endovascular aneurysm repair in high-risk patients. J Vasc Surg. 2000;31:122–133
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (347 KB)
    • CrossRef
17. Wald R, Waikar SS, Liangos O, Pereira BJ, Chertow GM, Jaber BL. Acute renal failure after endovascular vs open repair of abdominal aortic aneurysm. J Vasc Surg. 2006;43:460–466
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (103 KB)
    • CrossRef
18. Kubo S, Tadamura E, Yamamuro M, Hosokawa R, Kimura T, Kita T, et al. Thoracoabdominal-aortoiliac MDCT angiography using reduced dose of contrast material. AJR Am J Roentgenol. 2006;187:548–554
    • View In Article
    • CrossRef
19. Utsunomiya D, Awai K, Tamura Y, Nishiharu T, Urata J, Sakamoto T, et al. 16-MDCT aortography with a low-dose contrast material protocol. AJR Am J Roentgenol. 2006;186:374–378
    • View In Article
    • MEDLINE
    • CrossRef
20. Setty BN, Sahani DV, Ouellette-Piazzo K, Hahn PF, Shepard JA. Comparison of enhancement, image quality, cost, and adverse reactions using 2 different contrast medium concentrations for routine chest CT on 16-slice MDCT. J Comput Assist Tomogr. 2006;30:818–822
    • View In Article
    • MEDLINE
    • CrossRef
21. Willmann JK, Baumert B, Schertler T, Wildermuth S, Pfammatter T, Verdun FR, et al. Aortoiliac and lower extremity arteries assessed with 16-detector row CT angiography: prospective comparison with digital subtraction angiography. Radiology. 2005;236:1083–1093
    • View In Article
    • MEDLINE
    • CrossRef
22. Janka R, Fellner C, Wenkel E, Lang W, Bautz W, Fellner FA. Contrast-enhanced MR angiography of peripheral arteries including pedal vessels at 1.0 T: feasibility study with dedicated peripheral angiography coil. Radiology. 2005;235:319–326
    • View In Article
    • MEDLINE
    • CrossRef
23. Diehm N, Kickuth R, Baumgartner I, Srivastav SK, Gretener S, Husmann MJ, et al. Magnetic resonance angiography in infrapopliteal arterial disease: prospective comparison of 1.5 and 3 Tesla magnetic resonance imaging. Invest Radiol. 2007;42:467–476
    • View In Article
    • MEDLINE
    • CrossRef
24. Berg KJ. Nephrotoxicity related to contrast media. Scand J Urol Nephrol. 2000;34:317–322
    • View In Article
    • MEDLINE
    • CrossRef
25. Schoellnast H, Tillich M, Deutschmann MJ, Deutschmann HA, Schaffler GJ, Portugaller HR. Aortoiliac enhancement during computed tomography angiography with reduced contrast material dose and saline solution flush: influence on magnitude and uniformity of the contrast column. Invest Radiol. 2004;39:20–26
    • View In Article
    • MEDLINE
    • CrossRef
26. Bae KT, Tao C, Gurel S, Hong C, Zhu F, Gebke TA, et al. Effect of patient weight and scanning duration on contrast enhancement during pulmonary multidetector CT angiography. Radiology. 2007;242:582–589
    • View In Article
    • MEDLINE
    • CrossRef
27. Dewey M, Hoffmann H, Hamm B. CT coronary angiography using 16 and 64 simultaneous detector rows: intraindividual comparison. Rofo. 2007;179:581–586
    • View In Article
    • MEDLINE
    • CrossRef
28. Teutelink A, Muhs BE, Vincken KL, Bartels LW, Cornelissen SA, van Herwaarden JA, et al. Use of dynamic computed tomography to evaluate pre- and postoperative aortic changes in AAA patients undergoing endovascular aneurysm repair. J Endovasc Ther. 2007;14:44–49
    • View In Article
    • MEDLINE
    • CrossRef
29. Fleischmann D. Present and future trends in multiple detector-row CT applications: CT angiography. Eur Radiol. 2002;12(suppl 2):S11–S15
    • View In Article
    • CrossRef
30. Fleischmann D. Use of high concentration contrast media: principles and rationale-vascular district. Eur J Radiol. 2003;45(suppl 1):S88–S93
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (243 KB)
    • CrossRef
31. de Monye C, Cademartiri F, de Weert TT, Siepman DA, Dippel DW, van Der Lugt A. Sixteen-detector row CT angiography of carotid arteries: comparison of different volumes of contrast material with and without a bolus chaser. Radiology. 2005;237:555–562
    • View In Article
    • MEDLINE
    • CrossRef
32. Cademartiri F, Mollet NR, Runza G, Belgrano M, Malagutti P, Meijboom BW, et al. Diagnostic accuracy of multislice computed tomography coronary angiography is improved at low heart rates. Int J Cardiovasc Imaging. 2006;22:101–105
    • View In Article
    • MEDLINE
    • CrossRef
33. Cademartiri F, Mollet NR, van der Lugt A, McFadden EP, Stijnen T, de Feyter PJ, et al. Intravenous contrast material administration at helical 16-detector row CT coronary angiography: effect of iodine concentration on vascular attenuation. Radiology. 2005;236:661–665
    • View In Article
    • MEDLINE
    • CrossRef
34. Tonnessen BH, Sternbergh WC, Money SR. Mid- and long-term device migration after endovascular abdominal aortic aneurysm repair: a comparison of AneuRx and Zenith endografts. J Vasc Surg. 2005;42:392–400
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (235 KB)
    • CrossRef