Computed Tomography Modalities Research Articles

Comparison of Spleen Volumes Estimated Using Planimetry and Prolate Ellipsoid Methods on MRI in Myelofibrosis Patients

Background: Splenomegaly is one of the most characteristic features of myelofibrosis (MF) with significant impact on the quality of life of patients. About 10% of MF patients present with severely symptomatic splenomegaly at diagnosis; another 50% develop it within 4 years of diagnosis. Pharmaceutical drug trials aimed at treating myelofibrosis have assessment of spleen size as one of its key trial endpoints. While assessment of spleen size (volume) by palpation is routinely performed in the clinic, unfortunately, it is not a precise and reliable method, a key requirement in drug trials. Medical imaging methods such as magnetic resonance imaging (MRI) and computed tomography (CT) provide a non-invasive approach to assessment of spleen volume. Both modalities allow acquisition of cross sectional abdominal images and enable full anatomical coverage of the spleen. Due to radiation concerns, MRI is preferred over CT modality. There are two approaches for analyzing cross sectional images for estimation of spleen volume - the planimetry method, that involves delineating spleen contours on each spleen slice to estimate complete spleen volume and the prolate ellipsoid method, that approximates the spleen to an ellipsoid structure and estimates spleen volume by using the prolate ellipsoid method (described below). The prolate method is a simple and quick way to assess spleen size compared to the planimetry method. However, the former method provides an approximate estimate of spleen size. The goal of this study was to compare the prolate method with planimetry method for estimating spleen volume for use in pharmaceutical clinical trials.Methods: A retrospective assessment of spleen volume in N=30 subjects with confirmed diagnosis of myelofibrosis was performed. All measurements were performed on T2 weighted MR images (5mm slice thickness/0.0 gap), acquired on MRI scanners from different manufacturers. All images were assessed for image quality prior to including them in the analysis and images without any images quality issues were included in this study. The analysis methods and calculation used for estimating spleen volume were as below:•Planimetry: Volume = ∑ [(Region of interest outlining the spleen boundary per slice) x (Slice thickness)].•Prolate Ellipsoid: Volume = 0.52 x (Longest diameter of the spleen) x (longest perpendicular diameter on the same trans-axial slice) x (vertical distance between the most superior and most inferior margins of the spleen)Results: Spleen volume estimated by planimetry and prolate method was 2113cc±1612cc and 2186cc±1538cc (mean ± Standard Deviation [S.D.]). The range of planimetry spleen volumes in this study was 210 to 5750cc. A plot of spleen volumes estimated using planimetry and prolate method showed high correlation (R2 = 0.97) between the two methods, however, the volume variation tends to increase for large spleen sizes. The Bland-Altman plot for comparing the two methods showed mean difference in measures (73 cc) and difference variation (1 S.D. =300cc).Conclusions: Prolate method is a simple and useful alternate method for assessing spleen volume that does not require any specialized software for delineating spleen boundaries. However, the implementation of prolate method is operator dependent and requires precise positioning of digital calipers on images. Future work involves comparing the two methods with respect to change in spleen volume compared to baseline, an assessment performed routinely in pharmaceutical clinical trials. DisclosuresNo relevant conflicts of interest to declare.

CT examination effective doses in Saudi Arabia

Patient effective doses and the associated radiation risks arising from particular computed tomography (CT) imaging procedures are assessed. The objectives of this research are to measure radiation doses for patients and to quantify the radiogenic risks from CT brain and chest procedures. Patient data were collected from five calibrated CT modality machines in Saudi Arabia. The results are from a study of a total of 60 patients examined during CT procedures using the calibrated CT units. For CT brain and chest, the mean patient effective doses were 1.9 mSv (with a range of 0.6–2.5 mSv) and 7.4 mSv (with a range of 0.5–34.8 mSv) respectively. The radiogenic risk to patients ranged from between 10−5 and 10−4 per procedure. With 65% of the CT procedure cases diagnosed as normal, this prompts re-evaluation of the referral criteria. The establishment of diagnostic reference levels (DRL) and implementation of radiation dose optimisation measures would further help reduce doses to optimal values.

Barriers and incentives for choosing to specialise in mammography– A survey of Australian undergraduate diagnostic radiography students

IntroductionThere is a projected shortage of radiographers working in breast screening in Australia. This study aimed to examine the perceived barriers and potential incentives among current undergraduate diagnostic radiography students to train, specialise and work in mammography. MethodsA survey was undertaken to assess students' experience of six modalities during both University study and clinical practice. Students were asked to rank their priority of which they would want to specialise and if training and working in mammography was an option. ResultsFrom 248 students invited to participate, 101 students replied to the survey. Students indicated that they had been taught all modalities, however not all students had experienced them on clinical placement. Most students had observed or performed ultrasound (US) (90%, 90%), Computed Tomography (CT) (97%, 75%) and fluoroscopy (80%, 52%), though very few had experience of mammography (55%, 8%). US, CT, and MRI were the modalities that most students would like to specialise in. Male students reported being discriminated against working in mammography as this is “female only” work. ConclusionStudents have more clinical access to the major modalities of US, CT and MRI, and this appears to be a major factor into why student wish to specialise in these modalities. Role extension and higher wages were given as possible incentives that would make specialising in Mammography more appealing. The gender divide may have to be bridged to enable crucial recruitment as male students feel discriminated against.

Imaging of neurovascular emergencies in pregnancy and puerperium.

Acute neurovascular events, though rare, can complicate pregnancy and postpartum period. It is important to be aware of these clinical conditions for reducing maternal and fetal morbidity and mortality. In this review, we present a few important neurovascular emergencies and their imaging manifestations by various imaging modalities-computed tomography (CT), magnetic resonance imaging (MRI), and digital subtraction angiography (DSA)-which presented at our institution in the peripartum period.

Relationship between brain computed tomography findings and bispectral index score in patients presenting with head trauma.

OBJECTIVE:Head trauma is one of the most important emergency health problems both in the world and in our country. The objective in our study is to (i) state the correlation between the findings of bispectral index score (BIS) and computed tomography (CT), which are used to evaluate the level of consciousness of patients with isolated head trauma, and (ii) investigate objective results about the patient’s level of consiousness/alertness according to the CT modality, which is used frequently.METHODS:This prospective study was carried out between 03.01.2014 and 09.01.2014 in the emergency department of Fatih Sultan Mehmet Education and Research Hospital. The average BIS scores were correlated with the Glasgow Coma Scale (GCS) point, the Canadian CT Head Rule major and minor criteria, and the pathologic findings in CT imaging. The patients’ demographic features, vital signs at admission, and arrival times at the hospital were investigated.RESULTS:In our study, 64 (31.7%) patients were female, and 138 (68.3%) patients were male. The mean BIS scores were 84.99±11.20 (86.05) and 93.78±3.80 (95.05) in patients with and without CT pathologies, respectively. The correlation between CT pathology and BIS scores was statistically significant: BIS scores were lower in patients with CT pathologies (p=0.001; p<0.01). There was a statistically significant positive correlation between the BIS and GCS scores (45.6%) (p<0.05).CONCLUSION:We showed that most head traumas occur after dangerous accidents, and according to the results, we can predict that males are more frequently affected than females. There was a statistically significant positive correlation between BIS scores and GCS points. In our study, the BIS scores were statistically significantly lower in patients with CT pathology than in patients without. We can predict that if the BIS score of the patient is low, then there will be the presence of pathology on CT imaging.

Inpainting approaches to fill in detector gaps in phase contrast computed tomography

Photon counting semiconductor detectors in radiation imaging present attractive properties, such as high efficiency, low noise, and energy sensitivity. The very complex electronics limits the sensitive area of current devices to a few square cm. This disadvantage is often compensated by tiling a larger matrix with an adequate number of detector units but this usually results in non-negligible insensitive gaps between two adjacent modules. When considering the case of Computed Tomography (CT), these gaps lead to degraded reconstructed images with severe streak and ring artifacts. This work presents two digital image processing solutions to fill in these gaps when considering the specific case of synchrotron radiation x-ray parallel beam phase contrast CT. While not discussed with experimental data, other CT modalities, such as spectral, cone beam and other geometries might benefit from the presented approaches.

New biomarkers and imaging approaches for the diagnosis of deep venous thrombosis.

Symptoms suggestive of deep vein thrombosis (DVT) are extremely common in clinical practice, but unfortunately nonspecific. In both ambulatory and inpatient settings, clinicians are often tasked with evaluating these concerns. Here, we review the most recent advances in biomarkers and imaging to diagnose lower extremity DVT. The modified Wells score remains the most supported clinical decision rule for risk stratifying patients. In uncomplicated patients, the D-dimer can be utilized with risk stratification to reasonably exclude lower extremity DVT in some patients. Although numerous biomarkers have been explored, soluble P-selectin has the most promise as a novel marker for DVT. Imaging will be required for many patients and ultrasound is the primary modality. Nuclear medicine techniques are under development, and computed tomography (CT) and magnetic resonance venography are reasonable alternatives in select patients. D-dimer is the only clinically applied biomarker for DVT diagnosis, with soluble P-selectin a promising novel biomarker. Recent studies have identified several other potential biomarkers. Ultrasound remains the imaging modality of choice, but CT, MRI, or nuclear medicine tests can be considered in select scenarios.

Assessing Foraminal Stenosis in the Cervical Spine: A Comparison of Three-Dimensional Computed Tomographic Surface Reconstruction to Two-Dimensional Modalities.

Study Design:Retrospective radiographic study.Objective:The optimal radiographic modality for assessing cervical foraminal stenosis is unclear. Determination on conventional axial cuts is made difficult due in part to the complex, oblique orientation of the cervical neuroforamen. The utility of 3-dimensonal (3D) computed tomography (CT) reconstruction in improving neuroforaminal assessment is not well understood. The objective of this study is to determine inter-rater variability in grading cervical foraminal stenosis using 3 different CT imaging modalities: 3D CT surface reconstructions (3DSR), 2D sagittal oblique multiplanar reformations (2D-SOMPR), and conventional 2D axial CT imaging.Methods:Pretreatment CT scans of 25 patients undergoing surgery for cervical spondylotic radiculopathy were analyzed at 2 levels: C5-C6 and C6-C7. Simple interrater agreement and kappa-Fleiss coefficients were calculated for each imaging modality and stenosis grade. Image reviewers (attending spine surgeon, attending neuroradiologist, spine fellow) interpreted each CT scan in 3 different formats: axial, 2D-SOMPR, and 3DSR. Four cervical foramina at 2 spinal levels were graded as normal (no stenosis), mild (≤25% stenosis), moderate (25%-50% stenosis), or severe (>50% stenosis).Results:Across all imaging modalities, interrater reliability was fair when grading foraminal stenosis (κ < 0.4). Agreement was lowest for the axial images (κ = 0.119) and highest for the 3D CT reconstructions (κ = 0.334). 2D-SOMPR images also led to improved interrater reliability when compared with axial images (κ = 0.255).Conclusion:Grading cervical foraminal stenosis using conventional axial CT imaging is difficult with low interrater reliability. CT modalities that provide a circumferential view of the cervical foramen, such as 2D-SOMPR and 3D CT reconstruction, had higher rates of interobserver reliability in grading foraminal stenosis than conventional axial cuts, with 3D having the highest. As these 3D reconstructions can be obtained at no additional cost or radiation exposure over a conventional CT scan, and because they can provide useful information in determining levels being considered for surgical decompression, we recommend they be utilized when evaluating cervical foramina.

Volumetric assessment of alveolar clefts: a literature review.

To conduct a review of the literature on methods for volumetric assessment of alveolar clefts and ascertain which methods are most precise to guide future research. The PubMed and MEDLINE databases were searched for English-language reports of clinical and in vitro studies with detailed descriptions of imaging modality, sample characteristics, and method for measurement of alveolar cleft volume. The search strategy yielded 34 articles, of which 14 were selected for in-depth analysis. According to the findings of computed tomography (CT)-based studies, the CT modalities and software employed for assessment were deemed reliable and satisfactory. Measurement of alveolar cleft volume by the proposed methods and using the equipment and software employed in the analyzed studies has high efficacy and efficiency and can be safely used for cleft lip and palate treatment planning.

Validation of ultrasonographic muscle thickness measurements as compared to the gold standard of computed tomography in dogs.

ObjectiveThe objective was to quantitatively evaluate the validity of ultrasonographic (US) muscle measurements as compared to the gold standard of computed tomography (CT) in the canine.DesignThis was a prospective study.PopulationTwenty-five, client-owned dogs scheduled for CT as part of a diagnostic work-up for the management of their primary disease process were included.Materials and MethodsSpecific appendicular (cubital flexors and extensors, coxofemoral flexors and extensors) and axial (temporalis, supraspinatus, infraspinatus, lumbar epaxials) muscle groups were selected for quantitative measure based on CT planning and patient position. Prior to CT scan, the skin over the muscle sites was shaved and marked with a permanent marker. Patient body position was determined based on the patient’s CT plan; positioning was consistent between CT and US imaging. To ensure identical imaging position for both CT and US measurements, radio-opaque fiducial markers were placed directly over the skin marks once the dog was positioned. Quantitative measurements (cm) for both lean muscle mass (LMM) and subcutaneous adipose (SQA) were recorded. Statistical comparisons between CT and US values were done separately for each site and type.ResultsMuscle groups and associated SQA measured by US and CT were not statistically different based on an adjusted p-value using Bonferroni’s correction (p < 0.0031). In addition, all LMM and SQA sites had good reliability and agreement (Cronbach’s α = 0.8 − 1.0) between the two metrics, excluding the coxofemoral extensor muscle group (Cronbach’s α = 0.73232). Linear regression analysis of muscle measures indicated close agreement (slope range 0.93–1.09) and minimal bias of variation (intercept range 0.05–0.11) between CT versus US modalities, with the exception of the coxofemoral extensor muscle. Similarly, SQA CT and US measures indicated close agreement with the slope range of 0.88–1.02 and minimal bias of variation with an intercept range of 0.021–0.098, excluding the cubital flexor and extensor groups. Additionally, the R2 values for these remaining LMM and SQA sites are reported as >0.897 for LLM and >0.8289 for SQA.ConclusionsUltrasound imaging of selected appendicular and axial muscle groups in dogs can provide comparable assessment of muscle thickness to the current gold standard, CT. In consideration of both statistical reliability to CT and cage-side accessibility, the temporalis, supraspinatus, infraspinatus, and lumbar epaxial LMM sites are considered the most useful targets for US LMM assessment in the canine. Our findings support the potential utility of US as a clinical tool in veterinary medicine to assess LMM status in patients. Additional studies are indicated to develop standardized protocols of its use in a cage-side setting and to elucidate the benefit of this modality, in conjunction with nutritional interventions, to manage body LLM stores in compromised patients.

Image Guided Virtual Autopsy: An Adjunct with Radiographic and Computed Tomography Modalities - An Important Tool in Forensic Identification

The forensic examination of dead bodies is very helpful in order to identify the person, cause of death, gender, and solving the mysterious cases. It includes a number of techniques, out of which autopsy is the primary investigation that is performed in every medicolegal case. Because of mutilation technologies, traditional autopsy technique is most disturbing in terms of emotions and rituals of relatives. The use of radiology in forensic science comprises performance, interpretation, and reporting of radiographs that is helpful in detecting those changes that are not clinically visible. Forensic radiology plays an important role for identification of humans in mass disasters, criminal investigations, and evaluation of cause of death. The introduction of radiological modalities in autopsy techniques is a complementary tool for forensic identification and is known as virtual autopsy. The advance imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) is used in virtual autopsy in order to visualize and reconstruct the internal organs to know the site, type, and depth of injury. This review elaborates the role of maxillofacial imaging in image-guided virtual autopsy.

Combined modalities of magnetic resonance imaging, endoscopy and computed tomography in the evaluation of tumor responses to definitive chemoradiotherapy in esophageal squamous cell carcinoma

PurposeTo explore the value of combined modalities, including anatomical and functional magnetic resonance imaging (MRI), endoscopy and computed tomography (CT), for the assessment of tumor responses to definitive chemoradiotherapy (dCRT) in esophageal squamous cell carcinoma (ESCC). MethodsSixty-seven patients with locally advanced ESCC were enrolled. Tumor response (TR) was assessed two months after the completion of dCRT. Evaluation criteria according to combined modalities, including MRI, endoscopy and CT, were established and compared with traditional criteria based on CT and endoscopy. Progression-free survival (PFS)⩾12months was used as the reference standard, and the accuracy of the two criteria in response assessment was analyzed. ResultsThirty-seven (55.2%) and 10 (14.9%) patients were considered to exhibit CR, as assessed by combined modalities and the traditional criteria, respectively. Using PFS⩾12months as a surrogate for CR, the sensitivity and specificity of the combined modalities were 82.4% and 88.9%, respectively, compared with 20.6% and 92.6% for the traditional criteria. TR assessed by combined modalities (CR vs. non-CR) was prognostic of PFS in univariate and multivariate analyses (Log-rank, P<0.0001; Cox regression, HR=0.114, 95% CI 0.048–0.272). ConclusionsTumor responses assessed by the combined modalities of MR, endoscopy and CT seemed highly predictive of prognosis after dCRT in ESCC patients.

Spectral K-edge subtraction imaging of experimental non-radioactive barium uptake in bone

PurposeTo evaluate the feasibility of using non-radioactive barium as a bone tracer for detection with synchrotron spectral K-edge subtraction (SKES) technique. MethodsMale rats of 1-month old (i.e., developing skeleton) and 8-month old (i.e., skeletally mature) were orally dosed with low dose of barium chloride (33mg/kg/day Ba2+) for 4weeks. The fore and hind limbs were dissected for imaging in projection and computed tomography modes at 100μm and 52μm pixel sizes. The SKES method utilizes a single bent Laue monochromator to prepare a 550eV energy spectrum to encompass the K-edge of barium (37.441keV), for collecting both ‘above’ and ‘below’ the K-edge data sets in a single scan. ResultsThe SKES has a very good focal size, thus limits the ‘crossover’ and motion artifacts. In juvenile rats, barium was mostly incorporated in the areas of high bone turnover such as at the growth plate and the trabecular surfaces, but also in the cortical bone as the animals were growing at the time of tracer administration. However, the adults incorporated approximately half the concentration and mainly in the areas where bone remodeling was predominant and occasionally in the periosteal and endosteal layers of the diaphyseal cortical bone. ConclusionsThe presented methodology is simple to implement and provides both structural and functional information, after labeling with barium, on bone micro-architecture and thus has great potential for in vivo imaging of pre-clinical animal models of musculoskeletal diseases to better understand their mechanisms and to evaluate the efficacy of pharmaceuticals.

An Effective Occipitomental View Enhancement Based on Adaptive Morphological Texture Analysis.

This paper aims to present an algorithm that specifically enhances maxillary sinuses using a novel contrast enhancement technique based on the adaptive morphological texture analysis for occipitomental view radiographs. First, the skull X-ray (SXR) is decomposed into rotational blocks (RBs). Second, each RB is rotated into various directions and processed using morphological kernels to obtain the dark and bright features. Third, a gradient-based block segmentation decomposes the interpolated feature maps into feature blocks (FBs). Finally, the histograms of FBs are equalized and overlaid locally to the input SXR. The performance of the proposed method was evaluated on an independent dataset, which comprises of 145 occipitomental view-based human SXR images. According to the experimental results, the proposed method is able to increase the diagnosis accuracy by 83.45% compared with the computed tomography modality as the gold standard.

TU‐H‐CAMPUS‐JeP2‐01: Inter‐Observer Delineation Comparison of Visible Glandular Breast Tissue On Magnetic Resonance Imaging and Computed Tomography (prone and Supine)

Purpose:Breast cancers predominantly arise from Glandular Breast Tissue (GBT). If the GBT can be treated effectively post‐operatively utilising radiotherapy this may be adequate volumetric coverage for adjuvant breast radiotherapy. Adequate imaging of the GBT is necessary and will be assessed between MRI and CT modalities. GBT visualisation is acknowledged to be qualitatively superior on Magnetic Resonance Image (MRI) compared to Computed Tomography (CT), the current radiotherapy imaging standard, however this has not been quantitatively assessed. For radiotherapy purposes it is important that any treatment volume can be consistently defined between observers. This study investigates the consistency of CT and MRI GBT contours for potential radiotherapy planning.Methods:Ten experts (9 breast radiation oncologists and 1 radiologist) contoured the extent of the visible GBT for 33 patients on MRI and CT (both without contrast), which was performed according to a contouring guideline in supine and prone patient positions. The GBT volume was not a conventional whole breast radiotherapy planning volume, but rather the extent of GBT that was indicated from the CT or MR imaging. Volumes were compared utilizing the dice similarity coefficient (DSC), kappa statistic, and Hausdorff Distances (HDs) to ascertain the modality that was most consistently volumed.Results:The inter‐observer concordance was of substantial agreement (kappa above 0.6) for the CT supine, CT prone, MRI supine and MRI prone datasets. The MRI GBT volumes were larger than the CT GBT volumes (p&lt;0.001). Inter‐observer conformity was higher for CT than MRI, although the magnitude of this difference was small (VOI&lt;0.04). Conformity between modalities (CT and MRI) was in agreement for both prone and supine, DSC=0.75. Prone GBT volumes were larger than supine for both MRI and CT.Conclusion:MRI improves the extent of GBT delineation. The role of MRI guided, GBT‐targeted radiotherapy requires investigation in a clinical trial.This work was supported by a grant number APP1033237 from Cancer Australia and the National Breast Cancer Foundation.

Multifunctional BSA-Au nanostars for photoacoustic imaging and X-ray computed tomography

We report the synthesis and characterization of bovine serum albumin-capped Au nanostars (BSA-AuNSs) for dual-modal computed tomography (CT)/photoacoustic (PA) imaging application. The BSA-AuNSs have an average size of 85nm, and a surface plasmon resonance (SPR) peak at approximately 770nm. They have excellent biocompatibility, good X-ray attenuation, and great PA contrast enhancement properties. When injected intravenously, liver signal markedly increases in both CT and PA modalities. The in vivo biodistribution studies and pathology results showed that the BSA-AuNSs were mainly excreted through the liver and intestines with no obvious biotoxicity. These results indicate that BSA-AuNSs have high potential to be used as dual-modal CT/PA imaging contrast agents or further used to develop targeted probes. This preliminary study suggests that PA tomography may be used to non-invasively trace the kinetics and biodistribution of the nanoparticles.

Abdominal CT Does Not Improve Outcome for Children with Suspected Acute Appendicitis.

IntroductionAcute appendicitis in children is a clinical diagnosis, which often requires preoperative confirmation with either ultrasound (US) or computed tomography (CT) studies. CTs expose children to radiation, which may increase the lifetime risk of developing malignancy. US in the pediatric population with appropriate clinical follow up and serial exam may be an effective diagnostic modality for many children without incurring the risk of radiation. The objective of the study was to compare the rate of appendiceal rupture and negative appendectomies between children with and without abdominal CTs; and to evaluate the same outcomes for children with and without USs to determine if there were any associations between imaging modalities and outcomes.MethodsWe conducted a retrospective chart review including emergency department (ED) and inpatient records from 1/1/2009–2/31/2010 and included patients with suspected acute appendicitis.Results1,493 children, aged less than one year to 20 years, were identified in the ED with suspected appendicitis. These patients presented with abdominal pain who had either a surgical consult or an abdominal imaging study to evaluate for appendicitis, or were transferred from an outside hospital or primary care physician office with the stated suspicion of acute appendicitis. Of these patients, 739 were sent home following evaluation in the ED and did not return within the subsequent two weeks and were therefore presumed not to have appendicitis. A total of 754 were admitted and form the study population, of which 20% received a CT, 53% US, and 8% received both. Of these 57%, 95% CI [53.5,60.5] had pathology-proven appendicitis. Appendicitis rates were similar for children with a CT (57%, 95% CI [49.6,64.4]) compared to those without (57%, 95% CI [52.9,61.0]). Children with perforation were similar between those with a CT (18%, 95% CI [12.3,23.7]) and those without (13%, 95% CI [10.3,15.7]). The proportion of children with a negative appendectomy was similar in both groups: CT (7%, 95% CI [2.1,11.9]), US (8%, 95% CI [4.7,11.3]) and neither (12%, 95% CI [5.9,18.1]).ConclusionIn this uncontrolled study, the accuracy of preoperative diagnosis of appendicitis and the incidence of pathology-proven perforation appendix were similar for children with suspected acute appendicitis whether they had CT, US or neither imaging, in conjunction with surgical consult. The imaging modality of CT was not associated with better outcomes for children presenting to the ED with suspected appendicitis.

A Case for Wide-Angle Breast Tomosynthesis

Conventional mammography is largely limited by superimposed anatomy. Digital breast tomosynthesis (DBT) and computed tomography (CT) alleviate this limitation but with added out-of-plane artifacts or limited chest wall coverage. This article presents a wide-angle breast tomosynthesis (WBT), aimed to provide a practical solution to these limitations, and offers an initial study of its utility in comparison with DBT and CT using a singular evaluation platform. Using an anthropomorphic virtual breast phantom, a Monte Carlo code modeled a breast imaging system for three modalities of DBT, WBT, and breast CT (44°, 99°, and 198° total angle range, respectively) at four breast compression levels, all at a constant mean glandular dose level of 1.5 mGy. Reconstructed volumes were generated using iterative reconstruction methods. Lesion detectability was estimated using contrast-to-noise ratio and a channelized Hotelling observer model in terms of the area under the receiver operating characteristic (AUC). Results showed improved detection with increased angular span and compression. The estimated AUCs for WBT were similar to that of CT. Comparative performance averaged over all thicknesses between CT and WBT was 4.3 ± 3.0%, whereas that between WBT and DBT was 5.6 ± 1.0%. At compression levels reflective of the modality (7-, 5-, and 4-cm thickness for CT, WBT, and DBT, respectively), WBT yielded an AUC comparable to CT (performance difference of 1.2%) but superior to DBT (performance difference of 5.5%). The proposed imaging modality showed significant advantages over conventional DBT. WBT exhibited superior imaging performance over DBT at lower compression levels, highlighting further potential for reduced breast compression.

Invited Commentary

Invited Commentary

Pulmonary nodule characterization, including computer analysis and quantitative features.

Pulmonary nodules are commonly detected in computed tomography (CT) chest screening of a high-risk population. The specific visual or quantitative features on CT or other modalities can be used to characterize the likelihood that a nodule is benign or malignant. Visual features on CT such as size, attenuation, location, morphology, edge characteristics, and other distinctive "signs" can be highly suggestive of a specific diagnosis and, in general, be used to determine the probability that a specific nodule is benign or malignant. Change in size, attenuation, and morphology on serial follow-up CT, or features on other modalities such as nuclear medicine studies or MRI, can also contribute to the characterization of lung nodules. Imaging analytics can objectively and reproducibly quantify nodule features on CT, nuclear medicine, and magnetic resonance imaging. Some quantitative techniques show great promise in helping to differentiate benign from malignant lesions or to stratify the risk of aggressive versus indolent neoplasm. In this article, we (1) summarize the visual characteristics, descriptors, and signs that may be helpful in management of nodules identified on screening CT, (2) discuss current quantitative and multimodality techniques that aid in the differentiation of nodules, and (3) highlight the power, pitfalls, and limitations of these various techniques.