Multidetector row CT angiography of the lower limb arteries: a prospective comparison of volume-rendered techniques and intra-arterial digital subtraction angiography

Diagnostic performance of computed tomography digital subtraction angiography of the lower extremities during haemodialysis in patients with suspected peripheral artery disease

INTRODUCTION

With intra-arterial digital subtraction angiography (DSA) considered as the gold standard, we compared the diagnostic value of computed tomography angiography (CTA) and computed tomography-digital subtraction angiography (CT-DSA in hemodialysis (HD) patients suspected of having lower limb peripheral artery disease (PAD).

METHODS

In this retrospective study, we enrolled 220 HD patients with suspected PAD. CT-DSA images were obtained by subtracting unenhanced images from enhanced images. The research team calculated the area under the curve (AUC), sensitivity, specificity, positive and negative predictive value (PPV, NPV), and recorded the diagnostic accuracy between the CTA and CT-DSA images using the DSA as gold standard. Visual evaluation of calcifications in the peripheral arteries were also compared between CTA and CT-DSA images.

RESULTS

At the above-knee level, the CTA AUC [95% confidence interval (CI)] was 0.68 (CI 0.64-0.72), sensitivity and specificity were 60 and 81%, PPV and NPV were 85 and 53%, and accuracy was 67%. Below the knee, these values were 0.66 (CI 0.62-0.70), 71 and 79%, 79 and 47%, and 66%. For CT-DSA, above-knee, the AUC [95% CI] was 0.88 (CI 0.85-0.91), sensitivity and specificity were 84 and 92%, PPV and NPV were 89 and 97%, and accuracy was 93%. Below the knee, these values were 0.95 (CI 0.93-0.97), 95 and 93%, 96 and 83%, and 93%. The scores for the visualization of calcification in the peripheral arteries was significantly higher for CT-DSA than CTA (p < 0.05).

CONCLUSIONS

CT-DSA helps to assess stenotic PAD with high calcification in the lower extremities of HD patients.

IMPLICATIONS FOR PRACTICE

On CT-DSA images, the severity of vascular calcification can be assessed for HD patients suspected of PAD of the lower extremities.

Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia

GUIDELINE SUMMARY

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Comparison Between Computed Tomography Angiography and Digital Subtraction Angiography in Critical Lower Limb Ischemia

Background:

CT Angiography (CTA) of aortoiliac and lower extremity arteries is a relatively recent innovation of CT imaging that has changed after the introduction of multi-detector row scanners.

Objective:

The study aimed to evaluate the diagnostic accuracy of Multidetector Computed Tomographic Angiography (MDCTA) in the assessment of arterial tree in patients with Peripheral Arterial Occlusive Disease (PAOD), as compared to Digital Subtraction Angiography (DSA).

Methods:

A single-center nonrandomized prospective study was conducted on 50 patients complaining of peripheral arterial disease (chronic stage) from February 2017 to October 2017. All the patients were exposed to DSA and CTA prior to definitive treatment. The images were then analyzed using maximum intensity projection, volume-rendered, and curved multiplane reformation techniques.

Results:

All the patients involved in this study were susceptible according to their clinical presentation. The statistical analysis exposed a highly significant difference between CTA and DSA in the assessment of stenosis at the level of Femoropopliteal segment (P<0.01), while for infrapopliteal segment, there was no statistically significant difference between CTA and DSA having 8% versus 14% insignificant stenosis and 62% versus 47% significant stenosis in CTA and DSA, respectively. The overall accuracy of CT angiography in the femoropopliteal segments was 95.20% while in the infrapopliteal segment it was 94.5%.

Conclusion:

Multidetector CT angiography was found to be a reliable alternative mean for pathoanatomical description of the arterial lesions in critical lower limb ischemia and its subsequent management in comparison to digital subtraction angiography.

Global vascular guidelines on the management of chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Combined Static and Dynamic Computed Tomography Angiography of Peripheral Artery Occlusive Disease: Comparison with Magnetic Resonance Angiography

PURPOSE

To compare in patients with known peripheral artery occlusive disease (PAOD), image quality of a combined CTA to a combined MRA protocol, including both static and dynamic acquisitions.

MATERIALS AND METHODS

Twenty-two patients with PAOD were examined with a combined CTA and MRA protocol consisting of static acquisitions (s-CTA, s-MRA) of the entire runoff and dynamic acquisitions (d-CTA, d-MRA) of the calves. Two radiologists compared image quality of the s-MRA versus s-CTA as well as d-MRA versus d-CTA. Image quality was assessed on a segmental basis using a 4-point Likert scale.

RESULTS

For s-CTA, 76% of segments were rated as excellent or good. For s-MRA, 50% of segments were rated as excellent or good (p < 0.0001). For d-CTA, median image quality score for all segments was rated as excellent for both readers. For d-MRA, median image quality for the different segments ranged from moderate to good. For both d-CTA and d-MRA, the median image quality scores were significantly higher for all segments of the lower limb compared with the static examinations of the lower limb segments (all p values < 0.0001). In patients with PAOD category 4-6, 80% of segments were rated as excellent or good for d-CTA, while 45% of segments were rated as poor or non-diagnostic for d-MRA.

CONCLUSION

In patients with known PAOD, a combined static and dynamic CTA examination improves image quality relative to static and dynamic MRA and should be considered as an alternative to MRA, particularly in patients with advanced stage PAOD.

Optimized Protocol for Fast CT Angiography of Lower Limbs Using 160-Row Detector

OBJECTIVE

We proposed and tested a novel acquisition protocol for optimizing a fast computed tomography angiography using a 160-row detector scanner using a longer contrast injection time coupled with multiphasic rate of injection.

METHODS

A prospective randomized study was performed to compare image quality, contrast enhancement, and radiation dose in 2 groups (a fast acquisition and a widely accepted slow acquisition).

RESULTS

There was no difference between groups regarding image quality, noise, and diagnostic performance, but we evidenced a trend to higher radiation dose for the fast acquisition protocol.

CONCLUSIONS

An optimized protocol for performing a fast acquisition computed tomography angiography of lower limbs is feasible, has sufficient diagnostic quality, and can be used in selected patients who would benefit from a short-time scan.

Clinical application of computed tomographic angiography in patients with renal arterial hemorrhage: Diagnostic accuracy and subsequent therapeutic outcome

The aim of the present study was to determine the accuracy of multi-section computed tomographic angiography (CTA) for the diagnosis of renal arterial h=emorrhage in comparison with digital subtraction angiography (DSA) and the effect of diagnostic outcome on therapeutic patient management. A retrospective analysis was conducted of the records of all patients undergoing DSA for acute renal hemorrhage between August 2005 and June 2014. A total of 74 patients were identified in whom CTA was performed prior to the DSA. DSA detected a renal arterial lesion in 68 cases and no bleeding was demonstrated in 6 cases. CTA correctly identified the bleeding site in 59 of the 68 DSA-positive cases. There were 14 patients with negative CTA results that underwent DSA after 2-10 days because of persistent hematuria, and 9 of them were found to have positive DSA results. The sensitivity, specificity, positive predictive value and negative predictive value of CTA for the detection of arterial lesions in the context of acute renal hemorrhage were 0.868, 0.833, 0.983 and 0.357, respectively. All patients with bleeding sites identified by DSA underwent superselective embolization in a single session. Five patients underwent a secondly embolization for recurrent hemorrhage. These results indicate that CTA is an accurate technique for the detection of major arterial hemorrhage and supports its use in the initial examination of these patients.

Diagnostic accuracy of dynamic computed tomographic angiographic of the lower leg in patients with critical limb ischemia

OBJECTIVE

The purpose of this study was to assess the diagnostic accuracy of dynamic computed tomographic angiography (dyn-CTA) in patients with critical lower leg ischemia.

MATERIALS AND METHODS

A population of 29 patients with known peripheral arterial occlusive disease (Fontaine stage III or IV) was examined with a combined CTA protocol consisting of a standard CTA (s-CTA) of the lower leg runoff from the diaphragm to the toes and dyn-CTA of the calves (scan range, 48 cm; 8 phases; 3.5 seconds per phase, 100 kV; 120 mAs; contrast volume, 50 mL; flow rate, 5.0 mL/s). Digital subtraction angiography was performed on all patients and served as a reference standard. For each of seven lower leg artery segments, arterial contrast and diagnostic confidence for stenosis assessment (3-point scale) were tested for s-CTA and dyn-CTA. Similarly, stenoses of calf-segments were classified on a 3-point scale separately for s-CTA and dyn-CTA and were compared with digital subtraction angiography to assess diagnostic accuracy.

RESULTS

Compared with s-CTA, dyn-CTA resulted in significantly higher arterial contrast enhancement (68% vs 46% optimal contrast; P < 0.01) and higher diagnostic confidence (64% vs 48% fully confident, respectively, P < 0.05). Dyn-CTA had a slightly higher sensitivity for the detection of significant stenosis (98.0% vs 96.6%), and for the detection of occlusion (95.4% vs 94.4%). Specificity for dyn-CTA was higher than for s-CTA, both for detection of stenosis (97.1% vs 92.2%) and especially for the detection of vessel occlusions (99.3% vs 94.4%; P < 0.05).

CONCLUSIONS

Compared with s-CTA, dyn-CTA provides improved arterial contrast enhancement, higher diagnostic confidence, and increased diagnostic accuracy for the detection of stenoses and occlusions in peripheral arterial occlusive disease patients.

[Impact of iterative reconstruction on shape reproducibility of three-dimensional computed tomography]

The purpose of this study was to evaluate the effect of an iterative reconstruction method (IR) on shape reproducibility in three-dimensional (3D) computed tomography images. We used an IR (sinogram-affirmed iterative reconstruction: SAFIRE) implemented in a 64-channel multi slice computed tomography system (Siemens, SOMATOM Definition AS). We scanned a simulated vessel phantom with 180-HU vessel contrast at various radiation doses and reconstructed axial images of filtered back projection (FBP) and SAFIRE. Then we reconstructed multi-planar reconstruction (MPR) and volume rendering (VR) images from the axial images. Roundness was evaluated from MPR images and vessel surface roughness was evaluated from pixel value profiles of a vessel in VR images and visual evaluation by radiological technologists. In comparison on equivalent dose, the roundness and roughness were improved with increase of SAFIRE strength level. However, in comparison on equivalent noise (standard deviation: SD) of axial images, SAFIRE strength levels of 2 to 5 were significantly inferior to FBP (p<0.05). SAFIRE strength of 1 with a dose reduction of 19% maintained the shape reproducibility in all evaluations. Therefore, it would be not appropriate to use the SD of axial image as index for the dose reduction rate determination of 3D-CT images.

64-section CT angiography in patients with critical limb ischaemia and severe claudication: comparison with digital subtractive angiography

AIM

To assess the utility of 64 section multidetector computed tomography (MDCT) lower-limb angiography in the evaluation of patients with critical limb ischaemia (CLI) or severe intermittent claudication (IC) in grading disease before endovascular treatment.

MATERIALS AND METHODS

Forty-one consecutive patients with CLI or severe IC were assessed using 64 section MDCT angiography. The MDCT examinations were compared with subsequent intra-arterial digital subtraction angiography (IADSA) examinations performed at the time of endovascular intervention. The MDCT and IADSA examinations were independently scrutinized by readers blinded to the results of the other imaging method.

RESULTS

For arterial segments with haemodynamically significant disease (stenosis ≥50%), the overall sensitivity, specificity, and accuracy of MDCT in patients with severe claudication and CLI was 99% (95% CI: 98-100%), 98% (95% CI: 97-100%) and 98% (95% CI: 97-99%), respectively. The positive predictive value (PPV) was 97% and the negative predictive value (NPV) was 99%.

CONCLUSIONS

MDCT angiography is a useful tool in the assessment of patients with severe claudication and CLI and can be reliably used to grade disease severity and plan treatment.

Uniform vascular enhancement of lower-extremity artery on CT angiography using test-injection monitoring at the central level of the scan range: a simulation flow phantom study with clinical correlation

RATIONALE AND OBJECTIVES

To evaluate the efficacy of variable contrast injection durations and scanning delay determined by test injection analysis of computed tomography angiography (CTA) of peripheral arteries.

MATERIALS AND METHODS

We used a flow phantom that simulates the hemodynamics in a lower extremity artery. We set the flow rate at the pump to 2.0 or 5.0 L/minute. In protocol 1, we adopted a variable contrast injection duration based on the peak enhancement time of the test injection monitoring at the central level of the scan range. In protocol 2, we adopted a fixed contrast injection duration. The scanning delay was determined with a conventional bolus-tracking technique monitoring at the top of the scan range. Mean arterial attenuation and difference between the maximum and minimum attenuation values were calculated. To verify the phantom study results, clinical study, including 16 patients was performed under protocol 1.

RESULTS

The mean attenuation values under protocols 1 and 2 were comparable (563.6 Hounsfield units [HU] and 535.0 HU, respectively) at a pump flow rate of 2.0 L/minute; at 5.0 L/minute, they were 289.4 HU and 328.8 HU. The difference between the maximum and minimum attenuation values was smaller under protocol 1 than protocol 2 (76.8 HU vs. 184.9 HU) at a pump flow of 2.0 L/minute and also smaller under protocol 1 than protocol 2 (79.7 HU vs. 203.8 HU) at 5.0 L/minute. In clinical study, the mean attenuation value was 332.6 +/- 51.9 HU, and the difference between the maximum and minimum attenuation values was 55.1 +/- 24.4 HU.

CONCLUSION

The object-specific injection duration based on test injection at the central level of the scan range provides sufficient and constant vascular enhancement at CTA.

Comparison between 64-row CT angiography and digital subtraction angiography in the study of lower extremities: personal experience

PURPOSE

This study was undertaken to evaluate the potential of 64-row multislice computed tomography (CT) versus digital subtraction angiography (DSA) in detecting significant lesions of lower-extremity inflow and runoff arteries.

MATERIALS AND METHODS

Fifty-three patients underwent 64-row multislice CT and DSA over a mean of 36 days. The vascular tree was divided into 33 segments. Three readers independently reviewed the axial CT scans and multiplanar oblique and two- and three-dimensional reconstructions (maximum intensity projection and volume rendering) images to assess degree of stenosis according to four categories: 1 (0%-49% stenosis); 2 (50%-99% stenosis); 3 (occluded); 4 (not evaluable). In all cases, DSA was performed by arterial catheterisation.

RESULTS

In 53 patients, 1,440 segments were evaluated (infrarenal aorta and 16 arterial segments for each leg; 42 bilateral studies, 11 unilateral studies). Compared with DSA, CT angiography yielded 97.2% sensitivity, 97% specificity, 92.5% positive predictive value, 98.9% negative predictive value, 97.1% diagnostic accuracy and 95.4% concordance on the degree of stenosis.

CONCLUSIONS

Sixty-four-row multislice CT proved to be helpful in detecting haemodynamically significant lesions in peripheral arterial occlusive disease and improved the results obtained with 4- and 16-slice multidetector CT. In addition, owing to the high spatial resolution and rigorous technique, no variations in the data obtained below the knee were detected, overcoming a limitation of earlier generations of CT scanners.

Lower Extremity Arterial Disease: Multidetector CT Angiography—Meta-Analysis

PURPOSE

To obtain the best available estimates of the diagnostic performance of multidetector computed tomographic (CT) angiography compared with that of digital subtraction angiography (DSA) in the assessment of symptomatic lower extremity arterial disease and to identify the most important sources of variation in diagnostic performance between studies.

MATERIALS AND METHODS

Reports of studies published from January 2000 through April 2006 in English, German, French, or Spanish were searched for by using the MEDLINE, EMBASE, and Cochrane databases. Studies were included if they allowed construction of 2 x 2 contingency tables for the detection of stenosis of 50% or greater at multidetector CT angiography compared with that at DSA -- the reference standard -- in patients with claudication or critical ischemia. Two observers extracted data about study design, patient characteristics, arterial tracts, and technical protocols. Random-effects summary receiver operating characteristic analysis was performed to examine the influence of these data on diagnostic performance.

RESULTS

Of the 70 studies initially identified, 12 were included in which multidetector CT angiography was used to evaluate 9541 arterial segments in 436 patients. The pooled sensitivity and specificity for detecting a stenosis of at least 50% per segment were 92% (95% confidence interval: 89%, 95%) and 93% (95% confidence interval: 91%, 95%), respectively. Three studies provided data about the diagnostic performance of multidetector CT angiography in subdivisions of the arterial tract. The diagnostic performance of multidetector CT angiography in the infrapopliteal tract was lower than but not significantly different from that in the aortoiliac (P > .11) and femoropopliteal (P > .40) tracts. Regression analysis showed that diagnostic performance was not significantly influenced by differences in study characteristics.

CONCLUSION

Multidetector CT angiography is an accurate diagnostic test in the assessment of arterial disease (> or =50% stenosis) of the entire lower extremity.

Multi-detector row computed tomography angiography of peripheral arterial disease

With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD.

Multipath curved planar reformation of the peripheral arterial tree in CT angiography

The study was approved by the institutional review board, and informed consent was obtained. The purpose of the study was to prospectively quantify the angular visibility range, determine the existence of orthogonal viewing pairs, and characterize the conditions that cause artifacts in multipath curved planar reformations (MPCPRs) of the peripheral arterial tree in 10 patients (eight men and two women; mean age, 69 years; range, 54-80 years) with peripheral arterial occlusive disease. Percentage of segments with the maximal possible visibility score of 1 was significantly greater (odds ratio, 1.42; P<.001) for MPCPRs than for maximum intensity projections. One or more orthogonal viewing pairs were identified for all above-knee arterial segments, and artifactual vessel distortion was observed when the vessel axis approached a horizontal course in MPCPRs.

CT Angiography of Peripheral Arterial Occlusive Disease

Lower extremity computed tomography angiography (CTA) is an effective, noninvasive, and robust imaging modality that is being used increasingly to evaluate patients with peripheral arterial occlusive disease (PAOD). It is important for vascular and interventional radiologists, and vascular surgeons to be familiar with the strengths and limitations, diagnostic accuracy, and practical application of lower extremity CTA. In this article, we review the technical principles of image acquisition, visualization techniques to effectively interpret the large volumetric datasets generated, and the current practical application of lower extremity CTA with respect to PAOD.

Diagnostic Accuracy of Multislice CT Angiography in Peripheral Arterial Disease

A systematic search of the PubMed and Medline databases of English literature was performed to determine the diagnostic accuracy of multislice computed tomographic (CT; MSCT) angiography in peripheral arterial disease (PAD) compared with digital subtraction angiography (DSA). Studies comparing MSCT angiography with DSA in peripheral vascular disease were included, and the diagnostic value of MSCT angiography in terms of sensitivity, specificity, and diagnostic accuracy was compared and analyzed. Ten studies (19 comparisons) met the criteria and were included for analysis. The pooled sensitivity, specificity, and accuracy rates were 92%, 91%, and 91%, respectively, at all arterial levels; 92%, 94%, and 93%, respectively, at aortoiliac arteries; 96%, 85%, and 92%, respectively, at femoropopliteal arteries; and 91%, 85%, and 87%, respectively, at infrapopliteal arteries. A significant difference was found in the sensitivity of MSCT angiography in PAD between four-slice CT and 16-slice CT, between aortoiliac and femoropopliteal arterial segments, and between femoropopliteal and infrapopliteal arterial segments (P<.05). This review demonstrates that MSCT angiography has a high diagnostic value and could be a reliable alternative to DSA in the diagnosis of PAD.

Imaging of peripheral arteries by 16-row multidetector computed tomography angiography: a feasible tool?

OBJECTIVE

To evaluate the efficacy of multidetector (16-row) computed tomography (MDCT) in imaging the upper and lower limb arterial tree in trauma and peripheral arterial occlusive disease (PAOD).

METHODS

Thirty-three patients underwent MDCT angiography (MDCTA) of the upper or the lower limb on 16-row MDCT scanner between November, 2004 and July, 2005. The findings were compared with the surgical outcome in cases with trauma and suspected arterial injuries or color Doppler correlation was obtained for patients of PAOD.

RESULTS

MDCTA allowed a comprehensive diagnostic work-up in all trauma cases with suspected arterial injuries. In the 23 cases of PAOD, MDCT adequately demonstrated the presence of stenosis or occlusion, its degree and extent, the presence of collaterals and plaques.

CONCLUSION

Our experience of CT angiography (CTA) with 16-row MDCT scanner has clearly demonstrated its efficacy as a promising, new, fast, accurate, safe and non-invasive imaging modality of choice in cases of trauma with suspected arterial injuries and as a useful screening modality in cases of PAOD for diagnosis and for grading.

CT angiography of peripheral arterial disease

Lower-extremity computed tomographic (CT) angiography (ie, peripheral CT angiography) is increasingly used to evaluate patients with peripheral arterial disease. It is therefore increasingly important for all vascular specialists to become familiar with the strengths and limitations of this new technique. The aims of this review are to explain the principles of scanning and injection technique for a wide range of CT scanners, to explain and illustrate the properties of current image postprocessing tools for effective visualization and treatment planning, and to provide an overview of current clinical applications of peripheral CT angiography.

Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease

PURPOSE

Major arterial hemorrhage is an uncommon but serious complication of pancreatitis with high morbidity and mortality. Digital subtraction angiography (DSA) has long been the gold standard for the detection of a visceral artery pseudoaneurysm or for the site of active bleeding in patients with pancreatitis. Multi-section CT angiography is a minimally invasive technique which can provide high-resolution and high-contrast images of the arterial lumen and wall, with a much lower risk of complication and morbidity compared to DSA. The aim of this study was to determine the accuracy of multi-section CT angiography for the diagnosis of arterial complications of inflammatory pancreatitic disease.

MATERIALS AND METHODS

A retrospective analysis of all patients undergoing visceral angiography for major bleeding as a complication of pancreatitis between 1998 and 2004 was performed. Twenty-nine studies in 25 patients (20 males, 5 females) with a mean age of 50.9 years (range 11-67 years) were identified where multi-section CT angiography was performed in the 24 h preceding the digital subtraction angiogram.

RESULTS

Digital subtraction angiography detected a pseudoaneurysm or contrast extravasation in 19 studies and no bleeding was demonstrated in 9 studies. CT angiography correctly identified the site and type of bleeding in 18 of the 19 positive studies. CT angiography detected extravasation of contrast in one study that was not demonstrated on digital subtraction angiography. The sensitivity and specificity for multi-section CT angiography for the detection of major arterial bleeding on a background of pancreatitis were 0.947 and 0.900, respectively.

CONCLUSION

Multi-section CT angiography is a sensitive and accurate technique for the detection of major arterial hemorrhage in inflammatory pancreatic disease and should be considered as the first investigation in the management of these patients.

Angiographic imaging of the lower extremities with multidetector CT

Multidetector CT (MDCT) has improved imaging of the arteries in the lower extremities. The main advantages of this novel technology are the exceptionally fast scan times, high spatial resolution, increased anatomic coverage, and capability to generate high-quality multiplanar reformations and three-dimensional (3-D) renderings from raw data that can be reprocessed easily and quickly. The applications of MDCT in imaging the lower extremities are multiple and varied. They include the evaluation of peripheral arterial occlusive and aneurysmal disease, the patency and integrity of bypass grafts, and arterial injury owing to trauma. This article describes the techniques of lower extremity MDCT angiography and its use in a few clinical applications.