Lower Extremity CT Angiography Research Articles

CT imaging using variable helical pitch scanning for lower extremity arterial disease: Reduced contrast medium dose, improved image quality and diagnostic accuracy

ObjectivesThis study aimed to explore the feasibility of reducing contrast medium (CM) volume, improving image quality and diagnostic accuracy using variable helical pitch (VHP) scanning for patients with lower extremity arterial disease (LEAD). Materials and MethodsEighty patients who underwent lower extremity CT angiography (CTA) were prospectively enrolled and randomly assigned to either the VHP group (n = 40) or the conventional group (n = 40). Quantitative parameters and qualitative scores were compared between the two groups. Additionally, out of these patients, 72 arteries from 18 patients had DSA as the reference standard, and the diagnostic accuracy for the degree of vessel stenosis was assessed and compared. ResultsIn the VHP group, the contrast volume was significantly lower than in the conventional group (79.55 ± 11.87 mL vs. 89.63 ± 10.03 mL, p < 0.001), showing a reduction of 12.7 %. For all image quality characteristics, scores in VHP group were significantly superior to those in the conventional groups (all p < 0.05). Quantitative analysis revealed that images from the VHP group exhibited superior CT enhancement, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in the anterior tibial arteries (ATA) and dorsali pedis arteries (DPA) compared to the conventional group (all p < 0.001). Moreover, segment-based analysis showed the VHP group had significantly higher positive predictive value (PPV) and accuracy than the conventional group (PPV: 100 % vs. 76.19 %, p = 0.01; accuracy: 100 % vs. 84.38 %, p = 0.01, respectively). ConclusionsThe implementation of the VHP protocol led to a 12.7% decrease in contrast medium dosage compared to the conventional lower extremity CTA scanning protocol. Furthermore, it improved image quality and diagnostic accuracy, particularly for arteries below the knee.

Impact of Structured Reporting of Lower Extremity CT Angiography on Report Quality and Workflow Efficiency.

We assessed the effects of structured reporting (SR) of lower extremity CT angiography (CTA) on report quality and workflow efficiency compared with conventional reports (CR). Surveys were conducted at an academic radiology department before and after the introduction of an SR template. Participants (n = 39, 21) rated report quality and report creation effort (1: very dissatisfied/low to 10: very satisfied/high) and whether SR represents an improvement over CR (1: completely disagree to 5: completely agree). Four residents and two supervising radiologists created both CR and SR of 40 CTA examinations. Report creation time was measured and the factual accuracy of residents' reports was judged. Report completeness (median 8.0 vs. 7.0, p = 0.016) and clinical usefulness (7.0 vs. 4.0, p = 0.029) were rated higher for SR. Supervising radiologists found report clarity improved by SR (8.0 vs. 4.5, p = 0.029). Report creation effort was unchanged (7.0 vs. 6.0, p > 0.05). SR was considered an improvement over CR (median 4.0, IQR,3.0-5.0). Report supervision was shortened by SR (6.2 ± 2.0 min vs. 10.6 ± 3.5 min, p < 0.001) but total time for report creation remained unchanged (36.6 ± 12.8 min vs. 36.4 ± 11.0 min, p > 0.05). Factual accuracy of residents' SR was deemed higher (8.0/9.5 vs. 7.0/7.0, p = 0.006/ < 0.001). In conclusion, SR has the potential to improve report quality and workflow efficiency for lower extremity CTA.

Improving image quality consistency and diagnostic accuracy in lower extremity CT angiography using a split-bolus contrast injection protocol.

To evaluate the clinical value of using a split-bolus contrast injection protocol in improving image quality consistency and diagnostic accuracy in lower extremity CT angiography (CTA). Fifty (mean age, 66 ± 12 years) and 39 (mean age, 66 ± 11 years) patients underwent CTA in the lower extremity arteries using split-bolus and fixed-bolus injection schemes, respectively. The objective and subjective image quality of the 2 groups were compared and the diagnostic efficacy for the degree of vessel stenosis was compared using digital subtraction angiography as the gold standard. A P < .05 was considered statistically significant. In comparison with the fixed-bolus scheme, the split-bolus scheme greatly improved the consistency of image quality of the low extremities by significantly increasing the arterial enhancement (337.87 ± 64.67HU vs. 254.74 ± 71.58HU, P < .001), signal-to-noise ratio (22.58 ± 11.64 vs. 7.14 ± 1.98, P < .001), and contrast-to-noise ratio (37.21 ± 10.46 vs. 31.10 ± 15.40, P = .041) in the infrapopliteal segment. The subjective image quality was better (P < .001) and the diagnostic accuracy was higher in the split-bolus group than in the fixed-bolus group (96.00% vs. 91.67%, P < .05, for diagnosing >50% stenosis, and 97.00% vs. 89.10%, P < .05, for diagnosing occlusion) for the infrapopliteal segment arteries. Compared with the fixed-bolus injection scheme, the split-bolus injection scheme improves the image quality consistency and diagnostic accuracy especially for the infrapopliteal segment arteries in lower extremity CTA. (1) The split-bolus injection scheme of CTA of the lower extremity arteries improves the overall image quality, uniformity of contrast enhancement. (2) Compared with the fixed-bolus injection scheme, the split-bolus injection scheme especially improves the infrapopliteal segment arteries image quality and diagnostic efficacy.

Low-iodine 40-keV virtual monoenergetic CT angiography of the lower extremities.

To evaluate a reduced iodine volume protocol for lower extremity CT angiography (CTA) using dual-energy CT (DECT). This retrospective study included consecutive patients who underwent lower extremity CTA from June to December 2022. A 10 ml 1:1 mixed test bolus was performed, followed by a 40 ml full bolus at a 2.5/s injection rate, using 400 mg/ml iodine contrast media. Conventional and 40 keV virtual monoenergetic images (VMI) were reconstructed. For both reconstructions, five main artery segments were assessed with a 3-point image quality score as well as quantitative attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements with diagnostic quality thresholds (respectively >150 HU and >3). Forty patients were included in the study (mean age 68 ± 12 yo). 200 artery segments were assessed. Median qualitative image scores were 3 [IQR, 3, 3] for both reconstructions. 40 keV VMI upgraded qualitative scores for 51 (26%) of patients, including 9 (5%) from nondiagnostic to diagnostic quality. 40 keV VMI obtained attenuation and CNR diagnostic quality for respectively 100% and 100% of segments, compared with 96% and 98% for conventional images (p < 0.001). Distal artery segments showed the most differences between 40 keV VMI and conventional images. A low-iodine lower extremity CTA protocol is feasible, with 40 keV virtual monoenergetic spectral reconstruction enabling maintained diagnostic image quality at the distal artery segments.

Iterative reconstruction vs deep learning image reconstruction: comparison of image quality and diagnostic accuracy of arterial stenosis in low-dose lower extremity CT angiography.

To compare image quality and diagnostic accuracy of arterial stenosis in low-dose lower-extremity CT angiography (CTA) between adaptive statistical iterative reconstruction-V (ASIR-V) and deep learning image reconstruction (DLIR) algorithms. 46 patients undergoing low-dose lower-extremity CTA were enrolled. Images were reconstructed using ASIR-V (blending factor of 50% (AV-50) and 100% (AV-100)) and DLIR (medium (DL-M), and high (DL-H)). CT values and standard deviation of the aorta, psoas, popliteal artery, popliteal and ankle muscles were measured. The edge-rise distance and edge-rise slope were calculated. The degrees of granularity and edge blurring were assessed using a 5-point scale. The stenosis degrees were measured on the four reconstructions, and their mean square errors against that of digital subtraction angiography were calculated and compared. For both ASIR-V and DLIR, higher reconstruction intensity generated lower noise and higher signal-to-noise ratio and contrast-to-noise ratio values. The standard deviation values in AV-100 images were significantly lower than other reconstructions. The two DLIR image groups had higher edge-rise slope and lower edge-rise distance (DL-M:1.79 ± 0.37 mm and DL-H:1.82 ± 0.38 mm vs AV-50:1.96 ± 0.39 mm and AV-100:2.01 ± 0.36 mm, p = 0.014) than ASIR-V images. The overall image quality of DLIR was rated higher than ASIR-V (DL-M:0.83 ± 0.61, DL-H:0.41 ± 0.62, AV-50:1.85 ± 0.60 and AV-100:2.37 ± 0.77, p < 0.001), with DL-H having the highest overall image quality score. For stenosis measurement, DL-H had the lowest mean-square-errors compared to digital subtraction angiography among all reconstruction groups. DLIR images had higher image quality ratings with lower image noise and sharper vessel walls in low-dose lower-extremity CTA, and DL-H provides the best overall image quality and highest accuracy in diagnosing artery stenoses. DLIR provides high-quality images with sharper edges compared to ASIR-V during low-dose CTA of lower extremity arteries, and DLIR (high) provides the best overall image quality and highest accuracy in diagnosing artery stenoses among all reconstruction algorithms (ASIR-V and DLIR). ASIR-V with blending factor of 100% has the strongest noise reduction ability among all reconstruction algorithms (ASIR-V and DLIR); however, it generates the most blurred images.

515 Lower Extremity Atherosclerotic Plaque Burden And Composition Can Be Assessed Via CT Angiography With High Inter-reader Reproducibility

Introduction: Anatomical assessment of peripheral artery disease (PAD) with CT angiography (CTA) allows for plaque burden and composition analysis; establishing a reproducible analysis of this data will allow for evaluation of its clinical significance. In this study we establish inter-reader reproducibility of lower extremity CTA analysis for atherosclerotic plaque burden and composition.

Imaging Findings of Peripheral Arterial Disease on Lower-Extremity CT Angiography Using a Virtual Monoenergetic Imaging Algorithm.

Peripheral arterial disease (PAD) is common in elderly patients. Lower-extremity CT angiography (LE-CTA) can be useful for detecting PAD and planning its treatment. PAD can also be accurately evaluated on reconstructed monoenergetic images (MEIs) from low kiloelectron volt (keV) to high keV images using dual-energy CT. Low keV images generally provide higher contrast than high keV images but also feature more severe image noise. The noise-reduced virtual MEI reconstruction algorithm, called the Mono+ technique, was recently introduced to overcome such image noise. Therefore, this pictorial review aimed to present the imaging findings of PAD on LE-CTA and compare low and high keV images with those subjected to the Mono+ technique. We found that, in many cases, the overall and segmental image qualities were better and metal artifacts and venous contamination were decreased in the high keV images.

Peripheral intravascular lithotripsy to facilitate transfemoral TAVR: a multicentric prospective registry

Abstract Background The presence of severe calcific atherosclerotic disease at iliac artery level is a contraindication to transfemoral (TF) TAVI procedures, challenging TF delivery in 15–20% of cases. Many case reports described the efficacy of Intravascular lithotripsy (IVL) to facilitate TF access but only one prospective registry has been reported in literature and dates back 2018. For this reason a new multicenter prospective registry was ideated to confirm the role of IVL technology in facilitating TF TAVR. Aims The aims of this study were 1)to analyze the trend of TF TAVR compared to alternative approaches in the last 5 years and 2)to evaluate the prevalence of IVLassistedTAVR since it was introduced in this specific setting in 2018 3) to evaluate the success rate in terms of valve performance and procedural success of TF-TAVR system delivery after IVL lesion preparation. Materials and methods We prospectively collected data from all consecutive TAVRprocedures performed between Jan2016 andDec2020 at 4Italian and 1 Denmark centres. All patients underwent CT angiography of lower extremity before the procedure in order to assess the severity of aorto-iliac-femoral calcification and to select those patients who required specific lesion preparation to preserve TF access. For each target calcified lesion we measured length, diameter and %of stenosis, circumferential extension and minimal cross-sectional area. Angiographic IVL-related and access site complications (dissection, perforation, major bleeding) were examined. Results Between 2016 and 2020, a total of 3710 TAVR were performed, 3428 (92%) via TF route while the remaining 240 (8%) included alternative approaches mainly represented by subclavian and transapical access. IVL-assisted TAVR were 0 in 2016 and 2017, 13 (2%) in 2018 when the first IVL-assisted aortic valve implantation was performed and doubled in 2019, reaching a total of 112 in the whole 5-year period considered. The number of IVL-facilitated TAVR has been increased in the 5-year period, achieving 7% of the TF procedures while non-TF TAVR decreased considerably from 10% to 6%. Common and external iliac axis was the target lesion in the majority of cases (54%) followed by common iliac artery alone. lesion minimum diameter 4.7mm, with average stenosis of 50%. The maximum calcium angle was 332°. The majority of IVL was performed with a 7-mm catheter (78.6%). 1 balloon per lesion was employed. 1 perforation and 2 severe dissections occurred, that required stent placement. In 55% of cases the aortic regurgitation was absent or minimal. Conclusions TF approach remained the first choice for TAVR procedure in the majority of cases compared to non-TF thanks to the progressive increase of IVLassistedTAVR that allowed operators to preserve TF route. Peripheral IVL appeared feasible, safe and effective in patients with severe peripheral artery disease, with high success rate in terms of valve performance and low rate of complications. Funding Acknowledgement Type of funding sources: None.

CT iterative vs deep learning reconstruction: comparison of noise and sharpness.

To compare image noise and sharpness of vessels, liver, and muscle in lower extremity CT angiography between "adaptive statistical iterative reconstruction-V" (ASIR-V) and deep learning reconstruction "TrueFidelity" (TFI). Thirty-seven patients (mean age, 65.2 years; 32 men) with lower extremity CT angiography were enrolled between November and December 2019. Images were reconstructed with two ASIR-V (blending factor of 80% and 100% (AV-100)) and three TFI (low-, medium-, and high-strength-level (TF-H) settings). Two radiologists evaluated these images for vessels (aorta, femoral artery, and popliteal artery), liver, and psoas muscle. For quantitative analyses, conventional indicators (CT number, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR)) and blur metric values (indicating the degree of image sharpness) of selected regions of interest were determined. For qualitative analyses, the degrees of quantum mottle and blurring were assessed. The higher the blending factor in ASIR-V or the strength in TFI, the lower the noise, the higher the SNR and CNR values, and the higher the blur metric values in all structures. The SNR and CNR values of TF-H images were significantly higher than those of AV-80 images and similar to those of AV-100 images. The blur metric values in TFI images were significantly lower than those in ASIR-V images (p < 0.001), indicating increased sharpness. Among all the investigated image procedures, the overall qualitative image quality was best in TF-H images. TF-H was the most balanced image in terms of image noise and sharpness among the examined image combinations. • Deep learning image reconstruction "TrueFidelity" is superior to iterative reconstruction "ASIR-V" regarding image noise and sharpness. • The high-strength "TrueFidelity" approach generated the best image quality among the examined image reconstruction procedures. • In iterative and deep learning CT image reconstruction, the higher the blending and strength factors, the lower the image noise and the poorer the image sharpness.

Incidence and clinical impact of lower extremity vascular injuries in the setting of whole body computed tomography for trauma.

The aims of this study are to determine the incidence of lower extremity fractures and/or vascular injuries in the setting of whole body computed tomography (WBCT) for trauma and to determine lower extremity injury outcomes in this patient population. This is a retrospective observational study performed at a large urban Level 1 trauma center. Our institutional trauma registry was queried for patients who were evaluated with WBCT and lower extremity CT angiography (CTA) as a part of their initial imaging evaluation over a 43-month period. Patients with lower extremity fractures and/or vascular injuries were identified. Those patients with both lower extremity vascular injury and fracture were then analyzed to determine the physical relationship of the fracture to the vascular injury. Physical exam findings were extracted from the medical record. Interventions and long-term outcomes were determined from the medical record. A total of 370 patients met the inclusion criteria, with 98% experiencing blunt trauma. Of these, 290 (78.4%) were positive for lower extremity injury, including 266 (71.9%) with isolated fractures, 2 (0.6%) with isolated vascular injury, and 22 (5.9%) with vascular injury associated with long bone fracture. Of the 22 patients with combined fracture and vascular injury, 8 received vascular intervention and 10 had long-term complications as a result of their injuries. Physical exam findings were insufficient to diagnose 57% of the vascular injuries. The inclusion of lower extremity CTA as part of a WBCT imaging exam for trauma allows for the identification of vascular injuries that otherwise may have gone undetected or resulted in delayed diagnosis. Clinically occult lower extremity vascular injuries may be associated with poor outcomes.

Treatment of diabetic foot with vaccum sealing drainage combined with transverse tibial bone transport

To summarize the effectiveness and experience of Wanger grade 3-5 diabetic foot treated with vacuum sealing drainage (VSD) combined with transverse tibial bone transport. Between March 2015 and January 2018, 21 patients with refractory diabetic foot who failed conservative treatment were treated with VSD combined with transverse tibial bone transport. There were 15 males and 6 females, aged 55-88 years (mean, 65 years). The diabetes history was 8-15 years (mean, 12.2 years). The duration of diabetic foot ranged from 7 to 84 days (mean, 35.3 days). The size of diabetic foot ulcer before operation ranged from 2 cm×2 cm to 8 cm×5 cm. According to Wanger classification, 8 cases were rated as grade 3, 11 cases as grade 4, and 2 cases as grade 5. Among the 21 cases, angiography of lower extremity before operation was performed in 5 cases, CT angiography of lower extremity in 16 cases, all of which indicated that the arteries below the knee were narrowed to varying degrees and not completely blocked. Preoperative foot skin temperature was (29.28±0.77)℃, C-reactive protein was (38.03±31.23) mg/L, leukocyte count was (9.44±2.21)×10 9/L, and the visual analogue scale (VAS) score was 6.8±1.5, and ability of daily living (Barthel index) was 54.3±10.3. After operation, 2 patients with Wanger grade 4 and smoking history failed treatment and had an major amputation (amputation above ankle joint) at 30 days and 45 days after operation, respectively. One patient with Wanger grade 5 and chronic heart failure died of cardiac arrest at 60 days after operation. The remaining 18 patients were followed up 6-24 months (mean, 9.2 months). The external fixator was removed at 40-62 days after operation, with an average of 46 days. All the wounds healed, with a healing time of 50-120 days (mean, 62.5 days). The pain of 18 patients' feet was relieved obviously, and there was no recurrence of ulcer in situ or other parts. There was no complication such as tibial fracture and ischemic necrosis of lower leg skin after operation. After ulcer healing, the foot skin temperature was (30.86±0.80)℃, C-reactive protein was (22.90±18.42) mg/L, VAS score was 2.4±1.2, and Barthel index was 77.3±4.6, all showing significant differences when compared with preoperative ones ( P<0.05); the leukocyte count was (8.91±1.72)×10 9/L, showing no significant difference ( t=1.090, P=0.291). VSD combined with transverse tibial bone transport can effectively promote the healing of Wanger grade 3-5 diabetic foot wounds, but smokers, unstable blood glucose control, and chronic heart failure patients have the risk of failure.

Computed Tomography Angiography in Peripheral Arterial Disease: Comparison of Three Image Acquisition Techniques to Optimize Vascular Enhancement-Randomized Controlled Trial.

Objectives: To prospectively compare three image acquisition techniques in lower extremity CT angiography: the “standard” anterograde technique (SA), the adaptive anterograde technique (AA), and the retrograde acquisition technique (RA).Materials and Methods: Sixty consecutive patients were prospectively enrolled and randomized into three acquisition groups: 20 patients were evaluated with SA, 20 with AA as described by Qanadli et al., and 20 with caudocranial acquisition from the feet to the abdominal aorta (RA). Quantitative image quality was assessed by measuring the intraluminal attenuation at different levels of interest, with a total of 536 levels. Qualitative image quality was assessed by two radiologists in consensus using a Likert scale to rate the arterial enhancement and venous return. For each patient and limb, the presence of occlusive or aneurysmal disease was documented.Results: In quantitative analysis, RA showed lower attenuation values than SA and AA (p < 0.01). AA showed the highest and most homogeneous attenuation along the arterial tree. In qualitative analysis, AA had the lowest rate of non-diagnostic vascular segments (3.9%) compared to SA and RA (4.7 and 13.1%, respectively, p < 0.01). The influence of venous return was significantly different among the different techniques; venous contamination was particularly prevalent at the aortic level with RA (9.4% of patients, 0% with SA and AA, p < 0.01). The presence of stenosis or occlusion had no significant influence on the attenuation values across all levels and acquisition techniques. Conversely, the presence of aneurysmal disease had a significant effect on the luminal attenuation in AA (higher attenuation) and RA (lower attenuation) at the iliac (p = 0.03 and 0.04, respectively) and femoral levels (p = 0.02 and <0.01, respectively).Conclusion: Considering both quantitative and qualitative analysis, AA performed better than SA and RA, providing the highest percentage of optimal vascular enhancement. AA should be recommended as the technique of choice, specifically in the presence of aneurysmal disease. Alternatively, SA can be useful in case of renal failure, as the test bolus is unnecessary. Finally, the increasing availability of fast CT systems will likely overcome the limitations of RA.

CT angiography of lower extremities from anatomy to traumatic and nontraumatic lesions: a pictorial review.

After the introduction and the quick improvement of multidetector computed tomography technology, computed tomographic angiography (CTA) has become the imaging examination of choice for the first assessment of patients affected by lower extremities acute disorders. The widespread availability of CT equipment, the high temporal and spatial resolution with post-processing reformation possibilities represent the main advantages of this technique, which can reliably identify different findings related to arterial vessel pathology, such as occlusion, dissection, active bleeding, and pseudoaneurysm. Radiologists should know the anatomy, the acquisition protocols, and the CTA appearances of the different vascular lesions. The right interpretation of CTA findings is essential to establish the best treatment management of each patient.

Patient-Specific Guides for Acetabular Prosthesis result in Better Hip ROMs: a 3D Regeneration Research

Objective: Orientation of the acetabular prosthesis is extremely relevant for total hip arthroplasty (THA) stability, which is usually predicted by hip range of motion (ROM). The desired acetabular cup orientation includes inclination of 40° and anteversion of 15°. The classical method uses mechanical alignment as a guide, which could be unstable and unreliable. Two anatomical structures, transverse acetabular ligament (TAL) and ischiadic-pubis line (IPL) have been suggested as patient-specific guide for orientations. The purpose of this study was to provide a basis for selection of an optimal guide for orientation in THA practice, by comparing these methods in THA simulation model. Materials and Methods: CT angiography of lower extremities from 47 participants (94 hips) treated at Union Hospital were imported to Mimics to regenerate pelvis and bilateral femurs. The desired orientation was inclination of 40° and anteversion of 15°. Bilateral acetabular prosthesis for each participant was guided by TAL and IPL, respectively. Inclinations and anteversions of the TAL and IPL guided prosthesis were measured and compared with the goal. Hip joints were rotated outward, inward, backward and forward to evaluate four parameters of hip ROMs, i.e. abduction, adduction, extension and flexion. Hip joints were manipulated to perform circumduction and to draw boundary map. Result. The mean inclinations generated by TAL and IPL guides were 36.35° and 36.90° respectively, which was significantly smaller compared to goal inclination (p=2.2×10-16 and p=2.2×10-16 respectively). The mean anteversions generated TAL and IPL guides were 23.09° and 20.93°, which was significantly larger compared goal anteversion (p=2.2×10-16 and 2.2×10-16 respectively). The analysis of ROMs showed compared with hip ROMs by goal orientations, both TAL and IPL guides led to increased abduction (38.25°±8.30° and 38.47°±8.00° respectively, p<2×10-16 and p<2×10-16, respectively) and flexion (98.47°±9.71° and 100.50°±10.44°, p<2.2×10-16 and p<2.159×10-16, respectively); while decreased abduction (38.25°±8.30° and 38.47°±8.00°, p<2×10-16 and p<2×10-16, respectively) and extension (27.66°±10.18° and 25.93°±9.29°, p<2×10-16 and p<2×10-16, respectively). Conclusion. Compared with the goal orientations, the use of TAL and IPL guides led to greater motion in flexion and adduction, and lower motions in abduction and extension, thus suggesting these guides might be more suitable for post lateral THA.

Lower extremity CT angiography at 80 kVp using iterative model reconstruction.

To evaluate the use of 80 kVp and iterative model reconstruction (IMR) in lower extremity computed tomography angiography (CTA). Sixty patients were randomly assigned to Group A or Group B (both n=30) to further undergo CTA. Group A received Protocol 1 (P1) with 120 kVp, 180mAs, and 100mL of contrast agent with filtered back-projection (FBP). Group B received Protocol 2 (P2) and Protocol 3 (P3) with 80 kVp, 140mAs and 75mL of contrast agent with hybrid iterative reconstruction (P2) and IMR (P3). Mean intravascular attenuation (MIA), image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were compared. Radiologists assessed image quality on a 5-point scale, and radiation was compared between both groups. Group A had 9 men and 21 women (mean age, 68.2±9.3 years [range: 53-85 years]), and Group B had 20 men and 10 women (mean age, 64.8±10.4 years [range: 37-81 years]). The MIA of P2 and P3 were significantly larger than that of P1 (P<0.01). The CNR and SNR of P3 were significantly higher than those of P1 and P2 (P<0.01). The interobserver agreement had Kappa values of 0.78, 0.77, and 0.81 for P1, P2, P3, respectively. The mean CT volume dose index and dose-length product of Group B were lower than those of Group A (P<0.01). Lower extremity CTA using 80 kVp and IMR is useful for lower radiation and contrast agent dose while preserving image quality. IMR can also provide better image quality for small-caliber vessels below the knee than HIR.

Effect of Patient Characteristics on Vessel Enhancement at Lower Extremity CT Angiography.

ObjectiveTo evaluate the effect of patient characteristics on popliteal aortic contrast enhancement at lower extremity CT angiography (LE-CTA) scanning.Materials and MethodsPrior informed consent to participate was obtained from all 158 patients. All were examined using a routine protocol; the scanning parameters were tube voltage 100 kVp, tube current 100 mA to 770 mA (noise index 12), 0.5-second rotation, 1.25-mm detector row width, 0.516 beam pitch, and 41.2-mm table movement, and the contrast material was 85.0 mL. Cardiac output (CO) was measured with a portable electrical velocimeter within 5 minutes of starting the CT scan. To evaluate the effects of age, sex, body size, CO, and scan delay on the CT number of popliteal artery, the researchers used multivariate regression analysis.ResultsA significant positive correlation was seen between the CT number of the popliteal artery and the patient age (r = 0.39, p < 0.01). A significant inverse correlation was observed between the CT number of the popliteal artery and the height (r = −0.48), total body weight (r = −0.52), body mass index (r = −0.33), body surface area (BSA) (r = −0.56), lean body weight (r = −0.56), and CO (r = −0.35) (p < 0.001 for all). There was no significant correlation between the enhancement and the scan delay (r = 0.06, p = 0.47). The BSA, CO, and age had significant effects on the CT number (standardized regression: BSA −0.42, CO −0.22, age 0.15; p < 0.05, respectively).ConclusionThe BSA, CO, and age are significantly correlated with the CT number of the popliteal artery on LE-CTA.

Extremity CTA for penetrating trauma: 10-year experience using a 64-detector row CT scanner.

The purpose of this study is to assess the performance of CT angiography (CTA) in the evaluation of penetrating vascular trauma to the extremities in a large cohort of patients at our level I trauma center. A retrospective, IRB-approved review of consecutive CTAs for the evaluation of penetrating trauma to the extremities in 446 patients (M/F=396:50, mean age=27years) from 1/1/2005 to 5/1/2015 was performed. Medical records were reviewed to correlate diagnostic imaging findings with clinical history and subsequent interventions. Image quality was quantified by measurement of CT attenuation coefficients in the major arteries of the extremities. The Fisher's exact test was used to analyze the relationships between the presence and type of vascular injury and subsequent clinical management. One hundred and thirty-one (29.4%) of 446 patients with penetrating trauma demonstrated major vascular injury on CTA, 35 (26.7%) of whom underwent subsequent surgical repair. None of the patients without vascular injury on CTA underwent subsequent vascular intervention. Fisher's exact test demonstrated a statistically significant difference in management and requirement for vascular repair in those patients with a vascular injury on CTA when compared to those without a vascular injury (p<0.0001). The mean attenuation values achieved in upper and lower extremity CTAs in this population exceeded 250 HU. Extremity CTA is found to be an accurate tool for surgical triage in patients having sustained penetrating vascular trauma.

PC150. Lower Extremity CT Angiography Can Predict Technical Success of Endovascular Revascularization in the Superficial Femoral and Popliteal Arteries

OBJECTIVES Pre-procedural CT angiography (CTA) assists in evaluating vascular morphology, disease distribution and treatment planning in patients with lower extremity peripheral artery disease (PAD). The aim of the study was to determine the predictive value of radiographic findings on CTA and technical success of endovascular revascularization of occlusions in the superficial femoral-popliteal (SFA-pop) region.

Applied research of CT angiography of lower extremities by using 100 kVp and iodixanol(270 mg I/ml) combined with iDose(4) iterative reconstruction technique

To evaluate the feasibility of CT angiography of lower extremities by using 100 kVp as tube voltage and Iodixanol(270 mg I/ml) as contrast medium combined with iDose(4) iterative reconstruction technique. A total of 52 continuous patients with clinically suspected lesions of lower extremity arteries underwent CT angiography of lower extremities, divided into 2 groups, and different scan protocols were adopted. "double low" group included 26 patients using 100 kVp, Iodixanol (270 mg I/ml) and iDose(4) -4 iterative reconstruction algorithm; routine group included 26 patients using 120 kVp, Iopromide(370 mg I/ml) and filtered back projection reconstruction algorithm. The total amount of contrast medium in both groups was 95 ml. Artery CT value and background noise at the level of L4 vertebral, hip, knee and ankle were measured, signal to noise ratio (SNR) and contrast to noise ratio (CNR) were calculated, and the quality of images was evaluated subjectively. Scan length (L), volume CT dose index (CTDI(VOL)) and dose length product(DLP) were recorded, and the effective dose (ED) was calculated. The measurement results and subjective evaluation were analyzed statistically. CTA results were analyzed with the digital subtraction angiography (DSA) as the "gold standard". (1) No significant difference was existed in gender, age, height, weight and body mass index (BMI) of these two groups (P > 0.05). (2) No significant difference was existed in artery CT value, SNR and CNR at the level of L4 vertebral, hip, knee and ankle of the two groups (P > 0.05). Compared with routine group, background noise of "double low" group at the level of hip and knee increased by 16.6% and 13.8%, respectively (P < 0.05). (3) The image quality of the two groups met the requirement of diagnosis, no significant statistical difference was existed in subjective evaluation (P > 0.05). (4) The CTDI(VOL), DLP, ED of "double low" group were lower than that of routine group, with significant statistical difference (P < 0.05). The total amount of iodine in "double group" was lower than that of routine group (25.6 g vs 35.2 g). (5) A total of 7 cases from "double low" group underwent DSA examination, and 18 pathological changes (stenosis and occlusion) were found totally, in which 16 matched CTA; 6 cases from routine group underwent DSA examination, and 15 pathological changes (stenosis and occlusion) were found totally, in which 13 matched. CTA. No significant statistical difference was existed between the two groups in diagnostic efficacy (P = 0.626). Using 100 kVp and Iodixanol (270 mg I/ml) combined with iDose(4) -4 iterative reconstruction technique for CT angiography of lower extremities, the image quality could meet the requirement for clinical diagnosis, the radiation dose and the volume of contrast medium could be lowered.

Diagnostic performance and radiation dose of lower extremity CT angiography using a 128-slice dual source CT at 80 kVp and high pitch.

Multi-detector computed tomography (MDCT) angiography is now used for the diagnosing patients with peripheral arterial disease. The dose of radiation is related to variable factors, such as tube current, tube voltage, and helical pitch. To assess the diagnostic performance and radiation dose of lower extremity CT angiography (CTA) using a 128-slice dual source CT at 80 kVp and high pitch in patients with critical limb ischemia (CLI). Twenty-eight patients (mean, 64.1 years; range, 39-80 years) with CLI were enrolled in this retrospective study and underwent CTA using a 128-slice dual source CT at 80 kVp and high pitch and subsequent intra-arterial digital subtraction angiography (DSA), which was used as a reference standard for assessing diagnostic performance. For arterial segments with significant disease (>50% stenosis), overall sensitivity, specificity, and accuracy of lower extremity CTA were 94.8% (95% CI, 91.7-98.0%), 91.5% (95% CI, 87.7-95.2%), and 93.1% (95% CI, 90.6-95.6%), respectively, and its positive and negative predictive values were 91.0% (95% CI, 87.1-95.0%), and 95.1% (95% CI, 92.1-98.1%), respectively. Mean radiation dose delivered to lower extremities was 266.6 mGy.cm. Lower extremity CTA using a 128-slice dual source CT at 80 kVp and high pitch was found to have good diagnostic performance for the assessment of patients with CLI using an extremely low radiation dose.