Implementing a coronary CT angiography protocol based on the body mass index: Radiation dose reduction, image quality, and diagnostic performance

OBJECTIVES

To evaluate the relation between the coronary calcium score and the posterior choice of kilovoltage according to radiologists' criteria in a standard coronary CT angiography protocol to rule out coronary disease. To quantify the reduction in ionizing radiation after linking kilovoltage to patients' body mass index in a low-dose protocol with iterative model reconstruction. To evaluate the image quality and diagnostic performance of the low-dose protocol.

MATERIAL AND METHODS

We compared anthropometric characteristics, calcium score, kilovoltage levels, size-specific dose estimates (SSDE), and the dose-length product (DLP) between a group of 50 patients who were prospectively recruited to undergo coronary CT angiography with a low-dose protocol and a historical group of 50 patients who underwent coronary CT angiography with the standard protocol. We correlated these parameters, the number of coronary segments that could not be evaluated with and without temporal padding, the attenuation, and the signal-to-noise ratio in the ascending aorta in the low-dose protocol with excellent imaging quality according to a semiquantitative scale. To calculate the diagnostic performance per patient, we used 24-month clinical follow-up including all tests as the gold standard.

RESULTS

In the standard protocol, the presence of coronary calcium correlated with the selection of high kilovoltage (p = 0.02); this correlation was not found in the low-dose protocol (p = 0.47). Median values of SSDE and DLP were significantly (p < 0.001) lower and less dispersed in the low-dose protocol [9.22 mGy (IQR 7.84-12.1 mGy) vs. 26.5 mGy (IQR 21.3-36.3 mGy) in the standard protocol] and [97 mGy cm (IQR 78-134 mGy cm) vs. 253 mGy cm (IQR 216-404 mGy cm) in the standard protocol], respectively. The overall quality of the images obtained with the low-dose protocol was considered good or excellent in 96% of the studies. The parameters associated with image quality in a multivariable model (C statistic = 0.792) were heart rate (estimated coefficient, -0,12 [95% confidence interval: -0.2, -0.04]; p < 0.01) and the SSDE (estimated coefficient, -0,26 [95% confidence interval: -0.51, -0.01]; p < 0.05). The CAD-RADS modifier for a not fully evaluable or diagnostic study was used on two occasions (4%); the final measures for the diagnosis of coronary disease were sensitivity 100%, specificity 94%, and efficacy 94%.

CONCLUSIONS

In the standard protocol, the radiologist selects higher kilovoltage for CT angiography studies for patients whose previous calcium score indicates the presence of coronary calcium. In the low-dose protocol, linking kilovoltage with body mass index enables the dose of radiation to be reduced by 65% while obtaining excellent or good image quality in 96% of studies and excellent diagnostic performance.

What do we see when we do not see the bladder? Review of the main urinary diversion techniques and their complications

OBJECTIVE

To review the different types of urinary diversion surgeries (UDS) in order to recognize the expected findings in a postoperative study, using different imaging techniques. To recognize the main postoperative complications, both early and late.

CONCLUSION

UDS are surgical procedures whose purpose is to redirect urine flow after cystectomy, generally in an oncologic context. The imaging evaluation of urological surgeries is often a radiological challenge, with CT being the most commonly used image modality. Therefore, it is essential to know the main surgical techniques, the expected postoperative findings and the optimization of imaging techniques for early diagnosis and correct evaluation of postoperative complications.

Chronic expanding hematoma

Chronic expansive hematoma (CEH) is a rare lesion, characterized by the persistence and increase in size of an hematoma for a period greater than one month since the initial hemorrhage. The clinical importance of this pathology is due to the fact that it can simulate malignant soft tissue neoplasms, both clinically as a result of its progressive growth and radiologically for its findings in imaging studies. This article will review three cases of CEH in different scenarios, explaining the radiological findings in different imaging techniques such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and PET-CT.

Update on meningioma: Clinical-radiological and radio-pathological correlation

Meningiomas are tumors that originate in the arachnoid villi and are the most common non-glial neoplasm in the central nervous system. The clinical manifestations associated with meningioma depend, fundamentally, on its location. The location in the cerebral convexity is the most frequent, especially in the frontal lobes, manifesting with headache, motor disturbances, seizures and even neurocognitive disorders. There are 15 histologic subtypes of meningioma and three histologic grades. Within these, grades two and three have a worse prognosis and a higher rate of recurrence, as well as a radiological behavior that is generally more aggressive. Although there are some imaging features that can suggest a specific subtype, the definitive diagnosis will always require histological/molecular confirmation.

Recommendations on the use of computed tomography in the stroke code: Consensus document SENR, SERAU, GEECV-SEN, SERAM

The Spanish Society of Emergency Radiology (SERAU), the Spanish Society of Neuroradiology (SENR), the Spanish Society of Neurology through its Cerebrovascular Diseases Study Group (GEECV-SEN) and the Spanish Society of Medical Radiology (SERAM) have met to draft this consensus document that will review the use of computed tomography in the stroke code patients, focusing on its indications, the technique for its correct acquisition and the possible interpretation mistakes.

Incidence of contrast-induced nephropathy after a computed tomography scan

BACKGROUND AND AIMS

The term contrast-induced nephropathy is used to describe acute deterioration of renal function after the intravenous administration of iodinated contrast material. We aimed to estimate the incidence of contrast-induced nephropathy and to analyze the evolution of different biomarkers of renal function in patients who underwent computed tomography with intravenous contrast administration after premedication with oral hydration and N-acetylcysteine.

MATERIAL AND METHODS

This prospective observational study included 112 patients with chronic renal failure (glomerular filtration rate (GFR) 30ml-60ml/min/1.73m²) scheduled for computed tomography with intravenous iodinated contrast material. We recorded demographic variables, dose of contrast material, diabetes mellitus, hypertension, and serum hemoglobin. We measured serum creatinine and GFR after premedication and after the CT examination. We summarized variables as means, standard deviations, and percentages. We used the Wilcoxon and Mann-Whitney tests to compare pre- and post-CT values and Pearson's r to analyze correlations.

RESULTS

Incidence acute kidney injury: 0.9%; 95%CI: 0.36-1.4. Mean difference between pre- and post-CT creatinine: 0.04; 95%CI: 0.002-0.09, p<0.004. Mean difference between pre- and post-CT GFR: -3.06; 95%CI: -4.66 to -1.47), p<0.001.

CONCLUSIONS

The incidence of contrast-induced nephropathy in patients with chronic renal failure and GFR 30ml-60ml/min/1.73m² is low. The biomarkers of renal function analyzed improve in patients who receive premedication and the minimum dose of contrast material.

Multidetector computed tomography in planning the treatment of atrial fibrillation

OBJECTIVE

To know the anatomy of the pulmonary veins (PVs) by multidetector computed tomography (MDCT) in patients with atrial fibrillation (AF) prior to ablation.

MATERIALS AND METHODS

MDCT was performed in 89 patients with AF, analyzing the number of PVs, accessory variants and veins, diameter and ostial shape, distance to the first bifurcation and thrombus in the left atrial appendage.

RESULTS

The most frequent venous pattern was 4 PVs (two right and two. left) in 49 patients (55.1%). The superior veins had a statistically significant greater mean ostial diameter than the inferior veins (Right Superior Pulmonary Vein (RSPV)> Right Inferior Pulmonary Vein (RIPV); p=0.001 and Left Superior Pulmonary Vein (LSPV)> Left Inferior Pulmonary Vein (LIPV); p<0.001). The right pulmonary veins ostial diameters were significantly larger than the left pulmonary veins ostial diameters (RSPV> LSPV; p<0.001 and RIPV> LIPV; p<0.001). The most circular ostium was presented by the VPID (ratio: 0.885) compared to the LIPV (p<00.1) and LSPV (p<0.001). The superior veins had a statistically significant greater mean distance to first bifurcation than the inferior veins (RSPV> RIPV; p=0.008 and LSPV> LIPV; p=0.038). Mean distance to first bifurcation has been greater in left PVs respect to the right PVs (LSPV> RSPV; p<0.001and LIPV> RIPV; p<0.001). Other findings found in AI: diverticula (30), accessory auricular appendages (5), septal aneurysms (8), septal bags (6) and 1 thrombus in the left atrial appendage.

CONCLUSION

MDCT prior to ablation demonstrates the anatomy of the left atrium (LA) and pulmonary veins with significant differences between the diameters and morphology of the venous ostia.

Radiology of acute pancreatitis today: the Atlanta classification and the current role of imaging in its diagnosis and treatment

Acute pancreatitis is common and requires multidisciplinary management. The revised Atlanta classification, published in 2012, defines the terminology necessary to enable specialists from different backgrounds to discuss the morphological and clinical types of acute pancreatitis. Radiologists' role depends fundamentally on computed tomography (CT), which makes it possible to classify the morphology of this disease and to predict its clinical severity by applying imaging severity indices. Furthermore, CT- or ultrasound-guided drainage is, together with endoscopy, the current technique of choice in the initial approach to collections that appear as a complication. This paper aims to disseminate the concepts coined in the revised Atlanta classification and to describe the current role of radiologists in the diagnosis and treatment of acute pancreatitis.

Multidetector computed tomography for facial trauma: structured reports and key observations for a systematic approach

Facial fractures, often related to traffic accidents, assault, work-related accidents, or falls, account for a considerable number of emergencies in our hospitals and are associated with high morbidity and mortality. Multidetector computed tomography (MDCT) is the imaging technique of choice in this scenario because it is widely available, fast, and useful for characterizing facial fractures and associated complications, including those located in the head. For all these reasons, MDCT is fundamental in the clinical management of these patients and in planning surgery. This paper describes the radiological anatomy of the facial region, underlining the importance of the facial buttresses, and it indicates the key points necessary for carrying out a structured approach and elaborating the corresponding radiologic report.

Urgent Multidetector Computed Tomography in Colon Cancer: Postsurgical Changes and Early Complications

Complications after surgery for colorectal cancer are common in emergency departments. Multidetector computed tomography plays a fundamental role in the follow-up of patients after surgery, because it enables the detection of relapse and complications. Radiologists need to be familiar with different surgical techniques and the normal postsurgical changes so that we can differentiate them from potential complications and relapse. This article reviews the multidetector computed tomography findings that can be considered normal after surgical intervention for colorectal cancer as well as the most common early complications seen in postsurgical colorectal cancer patients presenting at emergency departments.

SEOM-SERAM-SEMNIM guidelines on the use of functional and molecular imaging techniques in advanced non-small-cell lung cancer

Imaging in oncology is an essential tool for patient management but its potential is being profoundly underutilized. Each of the techniques used in the diagnostic process also conveys functional information that can be relevant in treatment decision making. New imaging algorithms and techniques enhance our knowledge about the phenotype of the tumor and its potential response to different therapies. Functional imaging can be defined as the one that provides information beyond the purely morphological data, and include all the techniques that make it possible to measure specific physiological functions of the tumor, whereas molecular imaging would include techniques that allow us to measure metabolic changes. Functional and molecular techniques included in this document are based on multi-detector computed tomography (CT), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), magnetic resonance imaging (MRI), and hybrid equipments, integrating PET with CT (PET/CT) or MRI (PET-MRI). Lung cancer is one of the most frequent and deadly tumors although survival is increasing thanks to advances in diagnostic methods and new treatments. This increased survival poises challenges in terms of proper follow-up and definitions of response and progression, as exemplified by immune therapy-related pseudoprogression. In this consensus document, the use of functional and molecular imaging techniques will be addressed to exploit their current potential and explore future applications in the diagnosis, evaluation of response and detection of recurrence of advanced NSCLC.

Studying the complications of bariatric surgery with intravenous contrast-enhanced multidetector computed tomography

OBJECTIVE

To review the complications of bariatric surgery and their diagnosis with intravenous contrast-enhanced multidetector computed tomography (MDCT).

MATERIAL AND METHODS

We retrospectively studied all patients who underwent gastric bypass or sleeve gastrectomy at our center during 2013 or 2014. We classified complications into early complications (appearing within 30 days of the intervention) and late complications.

RESULTS

We reviewed 155 cases and found 24 complications in 22 patients: 16 early complications (7 intraperitoneal hematomas, 5 anastomotic dehiscences, 2 intestinal obstructions, and 2 external hernias) and 8 late complications (3 internal hernias, 3 intestinal perforations, and 2 marginal ulcers). Two patients died. All of these complications were diagnosed with intravenous contrast-enhanced MDCT, except one, which required a barium transit study.

CONCLUSION

The rate of complications in bariatric surgery is high and the associated mortality is not negligible. Radiologists need to know the normal findings in these patients so they can quickly identify possible complications, most of which can be diagnosed with intravenous contrast-enhanced MDCT.

Intracranial subarachnoid fat and hemorrhage secondary to sacral fracture with spondylopelvic dissociation

We describe a case of fat droplets and blood in the cerebral subarachnoid space secondary in a patient with a complex sacral fracture without associated cranial trauma, a few days after admission. To our knowledge, there is only one published case with similar findings and without any other underlying lesion as cause. We explain the differences in the mechanism of production between this direct fat embolism and brain fat embolism syndrome, which is an intravascular embolism with different radiological appearance. The most important features of sacral fracture with spondylopelvic dissociation are described. Finally, this entity should be taken into account in the differential diagnosis of the few causes of fat in the subarachnoid space. In the context of high-energy trauma fractures of the sacrum or spine must be ruled out as a potential cause of this uncommon intracranial finding.

The radiologist's role in the management of papillary renal cell carcinoma

Papillary carcinoma is the second most common renal cell carcinoma. It has a better prognosis than the more frequent clear cell carcinoma, although this does not hold true for advanced cases, because no specific treatment exists. It presents as a circumscribed peripheral tumor (small and homogeneously solid or larger and cystic/hemorrhagic) or as an infiltrating lesion that invades the veins, which has a worse prognosis. Due to their low vascular density, papillary renal cell carcinomas enhance less than other renal tumors, and this facilitates their characterization. On computed tomography, they might not enhance conclusively, and in these cases they are impossible to distinguish from hyperattenuating cysts. Contrast-enhanced ultrasonography and magnetic resonance imaging are more sensitive for detecting vascularization. Other characteristics include a specific vascular pattern, hypointensity on T2-weighted images, restricted water diffusion, and increased signal intensity in opposed phase images. We discuss the genetic, histologic, clinical, and radiological aspects of these tumors in which radiologists play a fundamental role in management.

Is urgent CT angiography necessary in cases of acute lower gastrointestinal bleeding?

Acute lower gastrointestinal bleeding usually presents as hematochezia, rectal bleeding or melena and represents 1-2% of the medical appointments in the Emergency Services. Mortality reaches the 30-40% and it is highly related with the severity and associated comorbidity. Most clinical practice guidelines include colonoscopy at some point in the diagnostic and therapeutic process (urgent for severe cases and ambulatory for mild ones) and look for predictors of severity. In the last years, there have been numerous studies where is clear the relevance and complementarity of advanced diagnostic imaging techniques, gradually incorporated as an alternative or second step in severe cases. Therefore, we have made a review of current scientific evidence to establish a clinical prediction rule for optimal indication of CT angiography in these patients. However, future studies providing greater robustness and level of evidence are necessary.

Computed tomography protocols used in staging bronchopulmonary carcinoma: results of a national survey

OBJECTIVES

To know the protocols used for staging bronchopulmonary carcinoma by computed tomography in Spain.

MATERIAL AND METHODS

Radiologists in 129 hospitals were sent email questionnaires about the organization of their department, scanner type and manufacturer, study extension, techniques employed, and protocol for administering contrast material.

RESULTS

A total of 109 hospitals responded with data from 91 teams. Most hospitals were affiliated with a university, and most departments were organized by organ-systems. Scanners were from four manufacturers, and 68% had either 16 or 64 detectors. In 61% of the hospitals, the dose of contrast agent is modified only in patients with extreme body weights, and in 22% the dose is not individualized. Most hospitals do contrast-enhanced studies of the chest and upper abdomen, 42.4% through a single thoracoabdominal acquisition and 55.9% through independent chest and abdominal acquisitions; there was a significant association between these approaches and the scanner manufacturer's protocols and whether the hospital was affiliated with a university. The most commonly used technical parameters were 120kV with dose modulation and variable milliamperage.

CONCLUSION

There is very little variability among hospitals in the type of scanner used, the study extension, and the technical parameters used to stage bronchopulmonary carcinoma. Most centers individualize the dose of contrast agent only in extreme weights. There is a broad division between using one or two acquisitions to image the thorax and abdomen, and the number of acquisitions is related to the scanner manufacturer and whether the hospital is affiliated with a university.

Multidetector computed tomography shows reverse cardiac remodeling after double lung transplantation for pulmonary hypertension

OBJECTIVE

To use multidetector computed tomography (MDCT) to evaluate the structural changes in the right heart and pulmonary arteries that occur in patients with severe pulmonary hypertension treated by double lung transplantation.

MATERIAL AND METHODS

This was a retrospective study of 21 consecutive patients diagnosed with severe pulmonary hypertension who underwent double lung transplantation at our center between 2010 and 2014. We analyzed the last MDCT study done before lung transplantation and the first MDCT study done after lung transplantation. We recorded the following variables: diameter of the pulmonary artery trunk, ratio of the diameter of the pulmonary artery trunk to the diameter of the ascending aorta, diameter of the right ventricle, ratio of the diameter of the left ventricle to the diameter of the right ventricle, and eccentricity index. Statistical analysis consisted of the comparison of the means of the variables recorded.

RESULTS

In all cases analyzed, the MDCT study done a mean of 24±14 days after double lung transplantation showed a significant reduction in the size of the right heart chambers, with improved indices of ventricular interdependency index, and reduction in the size of the pulmonary artery trunk (p<0.001 for all the variables analyzed).

CONCLUSION

Patients with pulmonary hypertension treated by double lung transplantation present early reverse remodeling of the changes in the structures of the right heart and pulmonary arterial tree. MDCT is useful for detecting these changes.

Hematologic neoplasms: interpreting lung findings in chest computed tomography

La patología pulmonar en la historia de un paciente con neoplasia hematológica es muy frecuente y variable en función de la enfermedad de base y la terapia recibida. La morbimortalidad asociada es alta, por lo que requiere un tratamiento correcto y precoz. La tomografía computarizada (TC) torácica, junto con el análisis de muestras biológicas, son las herramientas de diagnóstico de primera línea empleadas en estos pacientes, y en determinados casos se requieren métodos invasivos. La interpretación de las imágenes exige el análisis de un contexto clínico en muchas ocasiones complejo. Partiendo del conocimiento que adquiere el radiólogo en su formación sobre el diagnóstico diferencial de los hallazgos pulmonares, el objetivo de este trabajo es explicar los aspectos clínicos y radiológicos claves que permiten orientar correctamente el diagnóstico y asimilar el papel actual de la TC en la estrategia terapéutica de este grupo de enfermos.

Cam-type deformities: Concepts, criteria, and multidetector CT features

Interpreting imaging studies of a painful hip requires detailed knowledge of the regional anatomy. Some variants of the proximal femur, such as cam-type deformities, can course asymptomatically or cause femoroacetabular impingement. The principal numerical criterion for defining cam-type deformities, the alpha angle, has some limitations. In this article, we review the anatomic variants of the anterior aspect of the proximal femur, focusing on cam-type deformities. Using diagrams and multidetector CT images, we describe the parameters that are useful for characterizing these deformities in different imaging techniques. We also discuss the potential correspondence of imaging findings of cam-type deformities with the terms coined by anatomists and anthropologists to describe these phenomena.

[Secondary chondrosarcoma: radiopathological correlation]

Chondrosarcomas are malignant bone tumors originating in cartilage. Chondrosarcoma is the third most common malignant bone tumor after multiple myeloma and osteosarcoma. About 75% of chondrosarcomas are primary lesions. The remaining 25% belong to special categories such as histologic variants and secondary forms. A secondary chondrosarcoma is one that appears in a pre-existing benign chondral lesion; the different types of secondary chondrosarcomas include solitary osteochondroma, multiple osteochondromatosis, enchondroma, the different types of enchondromatosis, and primary synovial chondromatosis. The incidence of this malignant transformation varies widely in function of the type of lesion. In this article, we discuss and illustrate the different types of secondary chondrosarcomas, placing special emphasis on the imaging findings that should alert to these lesions and give radiologists a key role in the diagnosis, management, and follow-up of these patients.

[The different manifestations of pulmonary aspergillosis: multidetector computed tomography findings]

Pulmonary aspergillosis is a fungal infection usually caused by inhaling Aspergillus fumigatus spores. However, when we talk about aspergillosis, we normally refer to the spectrum of clinical and radiological findings that depend directly on the patient's immune status, on the prior existence of lung disease, and on the virulence of the infective organism. There are four types of pulmonary aspergillosis (aspergilloma, allergic bronchopulmonary aspergillosis, chronic necrotizing pulmonary aspergillosis, and invasive aspergillosis), and each type has its own distinct radiologic findings. We review the signs of pulmonary aspergillosis on multidetector computed tomography and we correlate them with patients' symptoms and immune responses. Likewise, we discuss the differential diagnoses.

Usefulness of coronary artery calcium for detecting significant coronary artery disease in asymptomatic individuals

OBJECTIVES

To confirm the value of the coronary artery calcium (CAC) score as an indicator of significant coronary artery disease (CAD) in the asymptomatic Spanish population, using noninvasive coronary angiography by multidetector computed tomography (MDCT).

METHODS

This was a retrospective study of 232 asymptomatic individuals, referred for a cardiovascular health checkup that included CAC and MDCT.

RESULTS

Participants' mean age was 54.6 years (SD ± 12.8); 73.3% of them were men. The mean CAC value was 117.8 (SD ± 277). The individuals with arterial hypertension, diabetes mellitus, smoking and 3 or more risk factors had significantly greater CAC scores. Some 16.4% of the participants were in the ≥75 percentile population for CAC. The MDCT identified 148 individuals (63.8%) with CAD; the coronary lesions were not significant in 116 individuals (50%) and were significant (>50% stenosis) in 32 (13.8%). The participants with diabetes, smoking and ≥3 risk vascular factors had a greater prevalence of significant stenosis. The individuals with >50% stenosis had higher CAC values (352.5 vs. 1; P<.0001), and those in the ≥75 percentile had a high percentage of significant lesions (57.9% vs. 5.2%; P<.0001). The predictors of significant CAD were a CAC score >300 (OR=10.9; 95% CI 3.35-35.8; P=.0001), belonging to the ≥75 percentile (OR=5.65; 95% CI 1.78-17.93; P=.03) and having 3 or more vascular risk factors (OR=4.19; 95% CI 1.44-12.14; P=.008).

CONCLUSION

CAC quantification is an effective method for determining the extent and magnitude of CAD and delimiting the predictive capacity of traditional risk factors.

[Laparoscopic gastric bypass: computed tomography appearance of common postoperative changes and complications]

Laparoscopic Roux-en-Y bypass is being increasingly used for weight reduction in patients with morbid obesity. Unfortunately, some complications can occur after this procedure, the most frequent being intestinal obstruction (due to stenosis of the anastomosis at the distal end of the loop, internal hernias, bands, and adhesions), anastomotic leaks, and bleeding. This article provides basic knowledge about the surgical technique and its correlation with the common postoperative changes with the aim of facilitating the interpretation of CT findings and the identification of postoperative complications in these patients.

Multidetector computed tomography in life-threatening hemoptysis

Life-threatening hemoptysis is a severe condition that requires rapid diagnosis and treatment. One of the treatments of choice is embolization. The initial assessment aims to locate the origin and cause of bleeding. The technological advance of the development of multidetector computed tomography (MDCT) has changed the management of patients with life-threatening hemoptysis. MDCT angiography makes it possible to evaluate the cause of bleeding and locate the vessels involved both rapidly and noninvasively; it is particularly useful for detecting ectopic bronchial arteries, nonbronchial systemic arteries, and pulmonary pseudoaneurysms. Performing MDCT angiography systematically before embolization enables better treatment planning. In this article, we review the pathophysiology and causes of life-threatening hemoptysis (including cryptogenic hemoptysis) and the MDCT angiography technique, and we review how to systematically evaluate the images (lung parenchyma, airways, and vascular structures).

[Review of pre- and post-treatment multidetector computed tomography findings in abdominal aortic aneurysms]

The increase in the frequency of abdominal aortic aneurysms (AAA) and the widely accepted use of endovascular aneurysm repair (EVAR) as a first-line treatment or as an alternative to conventional surgery make it necessary for radiologists to have thorough knowledge of the pre- and post-treatment findings. The high image quality provided by multidetector computed tomography (MDCT) enables CT angiography to play a fundamental role in the study of AAA and in planning treatment. The objective of this article is to review the cases of AAA in which CT angiography was the main imaging technique, so that radiologists will be able to detect the signs related to this disease, to diagnose it, to plan treatment, and to detect complications in the postoperative period.

Comparison of image quality and radiation dose in computed tomography angiography of the peripheral arteries using tube voltage of 80 kV versus 100 kV

OBJECTIVE

To compare the image quality and dose of radiation in two groups of patients undergoing CT angiography of the lower limbs, one with tube voltage of 80 kV and the other with tube voltage of 100 kV.

MATERIAL AND METHODS

We performed CT angiography of the lower limbs in 60 patients with suspected peripheral arterial disease. Patients were randomly assigned to one of two groups; in one group, CT angiography was performed using a tube voltage of 80kV, whereas in the other it was performed using 100 kV. The remaining acquisition parameters were the same in both groups. The images were analyzed by quantifying vascular density (VD) and noise (N) and by calculating the quotients density/noise (QVDN) and contrast/noise (QCN). Two radiologists working independently evaluated the subjective quality of the images. We calculated the estimated effective dose (EED) based on the dose-length product (DLP).

RESULTS

In the group studied at 80 kV, VD was significantly higher (462.5 UH ± 95.6 vs. 372 UH ± 100.9; P<.001), QVDN was significantly higher (241.9 ± 48.1 vs. 194.3 ± 49.6; P<.001), and there were trends toward higher N (21.3 UH ± 13 vs. 16.3 UH ± 3.5; P=.098) and toward higher QCN (21.4 ± 12.1 vs. 22.9 ± 9.1; P=.15). No significant differences were found in the subjective quality of the images. The EED was significantly lower in the group studied at 80 kV (4.73 mSv ± 1.1 vs. 9.6 mSv ± 2.2; P<.001).

CONCLUSION

Using 80 kV instead of 100 kV for CT angiography of the lower limbs reduces the dose of radiation without affecting the diagnostic efficacy of the study.