Multidetector Computed Tomography Technology Research Articles

Objective Analysis of Age-Related Changes in the Superficial Musculoaponeurotic System in Japanese Females Using Computed Tomography.

The superficial musculoaponeurotic system (SMAS) is an anatomical structure involved in facial aging. This study focused on SMAS thickness and aimed to establish age-related changes in SMAS thickness. A total of 100 adult Japanese female participants (aged 20-79 years) were enrolled in the study. The participants were divided into 3 age groups: Y, M, and E, comprising 20 to 39, 40 to 59, and 60 to 79 years, respectively. Anatomical structures were used as landmarks to standardize the SMAS analysis sites. The SMAS in a fixed analysis area (FAA) was quantified using multi-detector computed tomography (MDCT), and the relationship between SMAS thickness and age, as well as BMI, was analyzed. In 96 participants (four were excluded due to imaging artifacts), a moderate yet significant negative correlation was found between the average (A)-SMAS thickness within the FAA and age. The A-SMAS thickness in groups M and E was significantly lower than that of group Y, and the mean value of group E was significantly lower than that of group M. SMAS thickness was greater in the young population. The SMAS gradually became thinner with aging. A statistically significant correlation was not found between SMAS thickness and BMI. Using MDCT technology, age-related changes in SMAS were successfully analyzed. This highly objective analysis method corroborated the aesthetic surgical knowledge of the SMAS features related to facial aging. In clinical applications, our findings may help elucidate the mechanisms involved in facial aging.

New-generation multidetector computed tomography technology for the management of congenital heart disease in children: Now we can!

New-generation multidetector computed tomography technology for the management of congenital heart disease in children: Now we can!

New-generation multidetector computed tomography technology for the management of congenital heart disease in children: Now we can!

New-generation multidetector computed tomography technology for the management of congenital heart disease in children: Now we can!

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.

Pneumomediastinum in blunt trauma: If aerodigestive injury is not seen on CT, invasive workup is not indicated

BackgroundPneumomediastinum following blunt trauma is often observed on CT imaging, and concern for associated aerodigestive injury often prompts endoscopy and/or fluoroscopy. In recent years, adoption of multi-detector CT technology has resulted in high resolution images that may clearly identify aerodigestive injuries. The purpose of this study was to evaluate the utility of multi-detector CT in the identification of blunt aerodigestive injuries. MethodsOver five years, patients with pneumomediastinum following blunt trauma were identified from the registry of a level 1 trauma center. All CT imaging of trauma patients during this time period was accomplished with 64-slice scanners. Results127 patients with blunt traumatic pneumomediastinum were identified. Five airway injuries were identified, and all injuries were evident on CT imaging. No patient was found to have airway injury by endoscopy that was not evident on CT. No patient had an esophageal injury. ConclusionMulti-detector CT imaging identifies aerodigestive injuries associated with pneumomediastinum following blunt trauma. The absence of a recognizable aerodigestive injury by CT effectively rules out the presence of such injury.

The Added Value of Computer-aided Detection of Small Pulmonary Nodules and Missed Lung Cancers.

Lung cancer at its earliest stage is typically manifested on computed tomography as a pulmonary nodule, which could be detected by low-dose multidetector computed tomography technology and the use of thinner collimation. Within the last 2 decades, computer-aided detection (CAD) of pulmonary nodules has been developed to meet the increasing demand for lung cancer screening computed tomography with a larger set of images per scan. This review introduced the basic techniques and then summarized the up-to-date applications of CAD systems in clinical and research programs and in the low-dose lung cancer screening trials, especially in the detection of small pulmonary nodules and missed lung cancers. Many studies have already shown that the CAD systems could increase the sensitivity and reduce the false-positive rate in the diagnosis of pulmonary nodules, especially for the small and isolated nodules. Further improvements to the current CAD schemes are needed to detect nodules accurately, particularly for subsolid nodules.

Establishing and Running a Three-dimensional and Advanced Imaging Laboratory.

Multidetector CT technology has advanced during the past 2 decades from single-digit numbers of sections to 320-section CT scanners. The ability to perform three-dimensional (3D) postprocessing of acquired data has accompanied this technical progress. Multiple considerations are involved in developing and deploying a 3D and advanced imaging laboratory to provide postprocessing for both CT and MRI examinations. Establishing and running a 3D laboratory requires administrators to buy into the process and also requires regular input from radiologists and other stakeholders. Technologists with prior 3D experience are rare, and extensive immersive training is typically required. Laboratory space and equipment must be maintained and updated regularly to continue to meet stakeholders' needs. Postprocessing protocols must be established and reviewed periodically. Quality control is also necessary to ensure that postprocessing outputs adhere to the protocols. Laboratory technologists can also provide postprocessing support for research examinations and can lend their technical expertise to research projects. Regular review of laboratory productivity is essential to ensure longevity and availability of necessary resources (human, environmental, and technical). As the technologies for the imaging equipment, the picture archiving and communication system, and postprocessing continue to advance, the role of the 3D laboratory will also evolve to include other services. This evolution will affect ongoing training of technologists, as well as the requirements when new technologists are hired. The 3D laboratory is often positioned to take on novel technology and augment radiologists' workflow as new modalities and techniques enter the clinical workflow. ©RSNA, 2018.

Usefulness of spinal unenhanced computed tomography and CT-myelography in the age of multidetector CT technology and magnetic resonance imaging - Preliminary considerations.

Over the last decade, magnetic resonance imaging (MRI) and multidetector computed tomography (MDCT) have revolutionized diagnostic potential in small animal practice, providing adequate assessment of spinal diseases at levels comparable to that achieved in human radiology. T2-weighted MRI images are extremely sensitive to intramedullary parenchymal disorders, while balanced steady-state free precession sequences provide high-quality myelographic images of the spine without the need of intrathecal contrast medium administration. Multidetector computed tomography, with its near-isotropic spatial resolution and multiplanar reformatting of the acquired datasets, provides sufficient stratigraphic details of the spinal cord and the epidural space, facilitating the detection of compressive pathologies without the need of subarachnoid opacification. Nowadays, MDCT and low-field (LF) MRI have become fairly standard and available in academic institutions and private veterinary facilities, appearing to be valuable, complementary, and non-invasive diagnostic tools for imaging the spine. In this scenario, this clinical communication provides a series of preliminary observations that may help to reconsider the usefulness of CT-myelography in the light of its invasiveness and actual diagnostic advantages compared to MRI and unenhanced MDCT for the assessment of compressive and non-compressive spinal diseases in small animals.

Quantitative imaging of peripheral trabecular bone microarchitecture using MDCT.

Osteoporosis associated with reduced bone mineral density (BMD) and microarchitectural changes puts patients at an elevated risk of fracture. Modern multidetector row CT (MDCT) technology, producing high spatial resolution at increasingly lower dose radiation, is emerging as a viable modality for trabecular bone (Tb) imaging. Wide variation in CT scanners raises concerns of data uniformity in multisite and longitudinal studies. A comprehensive cadaveric study was performed to evaluate MDCT-derived Tb microarchitectural measures. A human pilot study was performed comparing continuity of Tb measures estimated from two MDCT scanners with significantly different image resolution features. Micro-CT imaging of cadaveric ankle specimens (n=25) was used to examine the validity of MDCT-derived Tb microarchitectural measures. Repeat scan reproducibility of MDCT-based Tb measures and their ability to predict mechanical properties were examined. To assess multiscanner data continuity of Tb measures, the distal tibias of 20 volunteers (age:26.2±4.5Y,10F) were scanned using the Siemens SOMATOM Definition Flash and the higher resolution Siemens SOMATOM Force scanners with an average 45-day time gap between scans. The correlation of Tb measures derived from the two scanners over 30% and 60% peel regions at the 4% to 8% of distal tibia was analyzed. MDCT-based Tb measures characterizing bone network area density, plate-rod microarchitecture, and transverse trabeculae showed good correlations (r∈0.85,0.92) with the gold standard micro-CT-derived values of matching Tb measures. However, other MDCT-derived Tb measures characterizing trabecular thickness and separation, erosion index, and structure model index produced weak correlation (r<0.8) with their micro-CT-derived values. Most MDCT Tb measures were found repeatable (ICC∈0.94,0.98). The Tb plate-width measure showed a strong correlation (r = 0.89) with experimental yield stress, while the transverse trabecular measure produced the highest correlation (r = 0.81) with Young's modulus. The data continuity experiment showed that, despite significant differences in image resolution between two scanners (10% MTF along xy-plane and z-direction - Flash: 16.2 and 17.9 lp/cm; Force: 24.8 and 21.0 lp/cm), most Tb measures had high Pearson correlations (r > 0.95) between values estimated from the two scanners. Relatively lower correlation coefficients were observed for the bone network area density (r = 0.91) and Tb separation (r = 0.93) measures. Most MDCT-derived Tb microarchitectural measures are reproducible and their values derived from two scanners strongly correlate with each other as well as with bone strength. This study has highlighted those MDCT-derived measures which show the greatest promise for characterization of bone network area density, plate-rod and transverse trabecular distributions with a good correlation (r ≥ 0.85) compared with their micro-CT-derived values. At the same time, other measures representing trabecular thickness and separation, erosion index, and structure model index produced weak correlations (r < 0.8) with their micro-CT-derived values, failing to accurately portray the projected trabecular microarchitectural features. Strong correlations of Tb measures estimated from two scanners suggest that image data from different scanners can be used successfully in multisite and longitudinal studies with linear calibration required for some measures. In summary, modern MDCT scanners are suitable for effective quantitative imaging of peripheral Tb microarchitecture if care is taken to focus on appropriate quantitative metrics.

Semi-automatic volumetric measurement of response to chemotherapy in lung cancer patients: How wrong are we using RECIST?

ObjectivesLung cancer typically starts as a near-spherical lesion, but as it grows it may acquire an irregular radiologic formation. RECIST is based on the assumption that tumors are spherical, and consequently, proportional changes of tumor volume and parallel changes in tumor diameter, and vice versa. Hence, a 30% decrease in diameter (2r) implies a 65% decrease of volume, and a 20% increase in diameter implies a 73% increase of volume. Materials and methodsWe compared volumetric measurement based on multi-detector CT technology with calculated volume (CV) according to RECIST in a cohort of 43 patients with advanced, non-squamous cell type, lung cancer treated with a combination of platinum and pemetrexed. ResultsCV was larger than SMV in most patients both at baseline and at best overall response (BOR). The difference between the sum of volumes based on volumetric measurement (SMV) and CV was larger for higher sum of diameters. The Lin's concordance correlation coefficient between the percent changes in SMV and CV at BOR was 0.757. Of note, four patients (4/43, 9.5%) were categorized as PD according to the method of CV, but SD according to the method of SMV. ConclusionOur study highlights the importance of volumetric measurement for assessing response to treatment in lung cancer patients particularly showing large, irregular lesions.

Cardiac Computed Tomographic Angiography: Clinical Applications

Cardiovascular disease is the leading cause of morbidity and mortality worldwide. Cardiac imaging plays an important role in diagnosis and risk stratification of various cardiac diseases. Cardiac computed tomography added a major diagnostic value and led to reducing the need for invasive cardiac measures in many cardiac conditions. Cardiac computed tomography has emerged as an accurate anatomic method for detection of coronary artery disease. The negative predictive value to exclude significant coronary artery stenosis approaches 100%. Advances in multidetector computed tomography technology improved coronary arteries imaging during a single breath hold in a wide range of coronary pathologies. Appropriate patient preparation, image acquisition, and post processing techniques to detect coronary artery stenosis and plaque are prerequisites to achieving diagnostic image quality. Cardiac computed tomography applications also include assessment of cardiac structure and function, post myocardial infarction complications, electro anatomical mapping, and delineation of the pericardium.

Integrating Anatomical and Functional Assessment of Coronary Artery Disease: Can MDCT act as the lone Gatekeeper in the near Future?

Several multicenter trials have demonstrated the high diagnostic accuracy and clinical efficacy of modern coronary computed tomography angiography (CTA) when utilized to evaluate symptomatic patients with low-to-intermediate pretest probability of coronary artery disease (CAD). However, coronary CTA remains a purely anatomic test and further assessment with invasive coronary angiography or other non-invasive tests are occasionally required, with subsequent inherent risks and costs to patients and healthcare systems. Recently, remarkable advances in multidetector computed tomography technology has significantly improved temporal and spatial resolution of coronary CTA. In the past decade, initially in animal models and then in humans, stress myocardial perfusion imaging by computed tomography (CTP) evolved and is being increasingly studied. It is the purpose of this review to highlight recent updates in the CTP literature and try to figure how to place CTP in CAD management in the near future.

Acute Mesenteric Ischaemia

Acute mesenteric ischaemia (AMI) is a surgical emergency, and has a high mortality. The term AMI covers arterial embolism, arterial thrombosis, non-occlusive mesenteric ischaemia and venous thrombosis which all lead to ischaemia/reperfusion syndrome of the bowel. Multi-detector row helical CT (MDCT) technology has dramatically improved the performance of CT by allowing rapid volumetric data acquisition to provide increased resolution, leading to better identification of the site, level and cause of ischaemia. CT angiography for diagnosing mesenteric ischaemia is now highly sensitive and specific, and should be used as first line when AMI is suspected. The aim of management is to restore intestinal blood flow in a timely manner. Therapeutic decisions are based on the presence of peritonitis, the presence of irreversible ischaemia or infarcted segments of the bowel, the general condition of the patient and the pathophysiological process underlying the ischaemia. AMI remains a challenging condition with high mortality. There is a need for good general surgical cover on the intensive care unit, with continuing care and clinical review by experienced senior surgeons with an interest in this condition.

SPECT/CT and pulmonary embolism

Acute pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/P) scintigraphy or pulmonary CT angiography (CTPA). In recent years both techniques have improved. Many nuclear medicine centres have adopted the single photon emission CT (SPECT) technique as opposed to the planar technique for diagnosing PE. SPECT has been shown to have fewer indeterminate results and a higher diagnostic value. The latest improvement is the combination of a low-dose CT scan with a V/P SPECT scan in a hybrid tomograph. In a study comparing CTPA, planar scintigraphy and SPECT alone, SPECT/CT had the best diagnostic accuracy for PE. In addition, recent developments in the CTPA technique have made it possible to image the pulmonary arteries of the lungs in one breath-hold. This development is based on the change from a single-detector to multidetector CT technology with an increase in volume coverage per rotation and faster rotation. Furthermore, the dual energy CT technique is a promising modality that can provide functional imaging in combination with anatomical information. Newer high-end CT scanners and SPECT systems are able to visualize smaller subsegmental emboli. However, consensus is lacking regarding the clinical impact and treatment. In the present review, SPECT and SPECT in combination with low-dose CT, CTPA and dual energy CT are discussed in the context of diagnosing PE.

CT angiography in the abdomen: a pictorial review and update

The development of multidetector CT technology and helical scanning techniques has revolutionized the use of CT for primary diagnostic evaluation of the abdominal vasculature, particularly the arterial system. CT angiography has numerous benefits relative to conventional catheter angiography, and has largely replaced catheter-based techniques in many clinical algorithms. This pictorial review and update will cover important technical principles related to modern CT angiography (including contrast delivery and dose considerations), discuss relevant anatomy and variants, and illustrate numerous arterial conditions related to the abdominal aorta and branch vessels.

Triple Rule-out Computed Tomographic Angiography for Chest Pain: A Diagnostic Systematic Review and Meta-Analysis

The objective was to compare the image quality, diagnostic accuracy, radiation exposure, and contrast volume of "triple rule-out" (TRO) computed tomography (CT) to other diagnostic modalities commonly used to evaluate patients with nontraumatic chest pain (dedicated coronary, pulmonary embolism [PE], and aortic dissection CT; invasive coronary angiography; and nuclear stress testing). Four electronic databases were searched, along with reference lists and contacted content experts, for relevant studies from inception until October 2012. Eligible studies enrolled patients with nontraumatic chest pain, shortness of breath, suspected acute coronary syndrome (ACS), PE, or aortic dissection; used at least 64-slice CT technology; and compared TRO CT to another diagnostic modality. Eleven studies enrolling 3,539 patients (791 TRO and 2,748 non-TRO) were included (one randomized controlled trial and 10 observational). There was no significant difference in image quality between TRO and dedicated CT scans. TRO CT had the following pooled diagnostic accuracy estimates for coronary artery disease: sensitivity of 94.3% (95% confidence interval [CI] = 89.1% to 97.5%), specificity of 97.4% (95% CI = 96.1% to 98.4%), positive likelihood ratio (LR+) of 17.71 (95% CI = 3.92 to 79.96), and negative likelihood ratio (LR-) of 0.08 (95% CI = 0.02 to 0.27). There were insufficient numbers of patients with PE or aortic dissection to generate diagnostic accuracy estimates for these conditions. Use of TRO CT involved greater radiation exposure (mean difference [MD] = 4.84 mSv, 95% CI = 1.65 to 8.04 mSv) and contrast exposure (MD = 38.0 mL, 95% CI = 28.1 to 48.0 mL) compared to non-TRO CT patients. Triple rule-out CT is highly accurate for detecting coronary artery disease. Given the low (<1%) prevalence of PE and aortic dissection in the included studies, and the increased radiation and contrast exposure, there are insufficient data to recommend use of TRO CT in the diagnosis of these conditions.

Pertinent reportable incidental cardiac findings on chest CT without electrocardiography gating: review of 268 consecutive cases

Pertinent reportable cardiac findings on non-electrocardiography (ECG)-gated chest CT examinations have become easier to detect given recent advancements in multidetector CT technology. However, those findings are easily overlooked on routine chest CT without ECG gating given residual inherent cardiac motion artifact and non-cardiac indications. To describe and quantify the types of pertinent reportable cardiac findings that can be detected on chest CT examinations without ECG gating and evaluate how often they were reported. Two radiologists retrospectively reviewed (blinded to the original interpretation) 268 consecutive routine adult chest CT examinations without ECG gating for the presence of pertinent reportable cardiac findings. Retrospective interpretations were then compared with the original radiological reports. One hundred and sixty-three patients (61%) had pertinent reportable cardiac findings. The findings encountered included: coronary artery disease (n = 131; 80.0%), coronary artery bypass grafts (n = 10; 6.1%), left ventricular aneurysm (n = 1; 0.6%), valve calcification (n = 131; 80.0%), valve repair/replacement (n = 5; 3.1%), pericardial effusion (n = 33; 20.2%), left atrial appendage thrombus (n = 1; 0.6%), cardiac mass (n = 1; 0.6%), and cardiac chamber enlargement (n = 29; 17.8%). On the original radiological reports 22.3% of the pertinent reportable cardiac findings, detected by the two radiologists retrospectively, were not reported. Detection of pertinent reportable cardiac findings on routine chest CT examinations without ECG gating is possible. The high volume of chest CT examinations without ECG gating represents an opportunity for radiologists to comment on the presence or absence of cardiac disease which may influence future clinical decisions.

Blunt pancreatic trauma: evaluation with MDCT technology

The purpose of this paper is to determine the relative frequency of multi-detector CT (MDCT) findings of pancreatic injury in blunt trauma and to determine their diagnostic accuracy in predicting main pancreatic duct injury. Fifty-three patients (31 male, 22 female; mean 44.1 years) with blunt trauma and admission MDCT findings suspicious for pancreatic injury or who underwent MDCT and had a discharge diagnosis of pancreatic trauma were included in this study. Two radiologists reviewed all images and recorded findings suspicious for pancreatic injury, which were subsequently compared to surgical findings to generate diagnostic accuracy. MDCT imaging findings suggestive of pancreatic injury included low attenuation peripancreatic fluid (n = 51), hyperattenuating peripancreatic fluid (n = 13), pancreatic contusion (n = 7), active hemorrhage (n = 2), and pancreatic laceration (n = 16). Diagnostic accuracy of the various imaging findings varied for diagnosing main duct injury; there were highly sensitive, nonspecific imaging findings such as the presence of low attenuation peripancreatic fluid (sensitivity, 100 %; specificity 4.9 %) as well as insensitive, specific findings such as visualizing a pancreatic laceration involving >50 % of the parenchymal width (sensitivity, 50 %; specificity, 95.1 %). In the setting of blunt abdominal trauma, MDCT imaging findings can be grouped into two categories for determining integrity of the main pancreatic duct: indirect, highly sensitive but nonspecific findings and direct, specific but insensitive findings. Awareness of the clinical implications of the various MDCT imaging findings of pancreatic trauma is useful in interpreting their significance.

Management of Primary Group A Streptococcal Peritonitis: A Systematic Review

Over the past 20 years, there has been a global increase in the incidence and severity of group A streptococcal diseases. Primary group A streptococcal peritonitis is a life-threatening disease that may present in previously healthy individuals and progress to shock and severe organ dysfunction within a few hours. Our goal was to develop recommendations regarding the care of this group of patients. A systematic review of all adult cases of primary group A streptococcal peritonitis described in the English-language literature between January 1990 and December 2011. Thirty-two patients with a median age at diagnosis of 38 years and a male:female ratio of 1:4 are described. Exploratory laparotomy was performed in 25 patients, 17 of whom had undergone abdominal computed tomography (CT). Laparoscopic peritoneal lavage was performed in five patients, and, in two patients, no operative interventions were undertaken. The worrisome increase in invasive group A streptococcal disease means that presentations of primary group A streptococcal peritonitis are likely to become more common. The challenge for the treating surgeon is to consider the possibility of this diagnosis. In the current era of multi-detector CT technology, secondary peritonitis from an intra-abdominal source may be excluded reliably using abdominal CT. Exploratory laparotomy is not mandated, and paracentesis is sufficient to confirm the diagnosis and avoid operative morbidity in patients with localized intra-peritoneal fluid collections. Laparoscopic peritoneal lavage should be reserved for patients with widespread intra-peritoneal free fluid or whose condition deteriorates despite antibiotic therapy.

What is the role of calcium scoring in the age of coronary computed tomographic angiography?

Non-contrast-enhanced CT for coronary artery calcification (CAC) as a marker of coronary atherosclerosis has been studied extensively in the primary prevention setting. With rapidly evolving multidetector CT technology, contrast-enhanced coronary CT angiography (CCTA) has emerged as the non-invasive method of choice for detailed imaging of the coronary tree. In this review, we systematically evaluate the role of CAC testing in the age of CCTA in both asymptomatic and symptomatic patients, across varying levels of risk. Although the role of CAC testing is well established in asymptomatic subjects, its use in evaluating those with stable symptoms that represent possible obstructive coronary artery disease is controversial. Nevertheless, available data suggest that in low-to-intermediate risk symptomatic patients, CAC scanning may serve as an appropriate gatekeeper to further testing with either CCTA (if no or only mild CAC present) versus functional imaging or invasive coronary angiography (when moderate or severe CAC present). Given the strong short-term prognostic value of CAC = 0, studies are needed to further evaluate the role of CAC scanning in low-risk patients with acute chest pain presenting to the emergency room.