Impact of intraoperative fluoroscopic beam positioning relative to the hip and pelvis on perceived acetabular component position.

Background: Parallax is poorly understood and can mislead surgeons using intraoperative fluoroscopy (IF) to guide cup placement during anterior approach (AA) total hip arthroplasty. The purpose of this study was to examine how changes in fluoroscopic beam positioning in relation to the hip and pelvis affects the projected acetabular image.

Methods: An acetabular component was positioned in an anatomic pelvis model in 45° and 20° of abduction and anteversion, respectively using a computer assisted cup targeting system.

Association between pre- and intraorbital soft tissue volumes and the risk of orbital blowout fractures using CT-based volumetric measurements.

Orbital blowout fractures result from trauma which breaks the bony orbital wall while sparing the rim. Previous research into fracture mechanism has focused on bony anatomy. This study evaluates the role of preorbital and intraorbital soft tissue volume in fracture risk.

Horizontal Long Axis Imaging Plane for Evaluation of Right Ventricular Function on Cardiac Magnetic Resonance Imaging.

Purpose: The purpose of this study was to evaluate a horizontal long axis (HLA) magnetic resonance imaging (MRI) plane aligned to the long axis of the right ventricular (RV) cavity for functional analysis by comparing the measurement variability and time required for the analysis with that using a short-axis (SAX) image orientation.

Materials And Methods: Thirty-four cardiac MRI exams with cine balanced steady-state free precession image stacks in both the SAX and the HLA of the RV (RHLA) were evaluated. Two reviewers independently traced RV endocardial borders on each image of the cine stacks.

Peripheral Magnetic Resonance Lymphangiography: Techniques and Applications.

Peripheral lymphedema is a chronic progressive and debilitating disorder that results from abnormal lymphatic drainage. Advances in microsurgical techniques have led to the development of new treatment options for lymphedema that benefit from preoperative imaging to select the most appropriate surgical repair. Magnetic resonance (MR) lymphangiography is a noninvasive imaging modality capable of providing high-resolution 3D images of the lower extremities to define the severity and extent of lymphedema and depict individual lymphatic channels.

Dual-energy CT Aortography with 50% Reduced Iodine Dose Versus Single-energy CT Aortography with Standard Iodine Dose.

Rationale And Objectives: Because many patients with aortic pathology also have compromised renal function, we wished to investigate dual-energy computed tomography (DECT) aortography with 50% reduced iodine dose compared to single-energy computed tomography (SECT) aortography with standard iodine dose.

Materials And Methods: Fifty patients had DECT aortography with 50% reduced iodine dose. Thirty-four of these patients had prior SECT aortography with standard iodine dose.

Quantitating aortic regurgitation by cardiovascular magnetic resonance: significant variations due to slice location and breath holding.

Objectives: Compare variability in flow measurements by phase contrast MRI, performed at different locations in the aorta and pulmonary artery (PA) using breath-held (BH) and free-breathing (FB) sequences.

Methods: Fifty-seven patients with valvular heart disease, confirmed by echocardiography, were scanned using BH technique at 3 locations in the ascending aorta (SOV = sinus of Valsalva, STJ = sinotubular junction, ASC = ascending aorta at level of right pulmonary artery) and 2 locations in PA. Single FB measurement was obtained at STJ for aorta.

Dark Blood Magnetic Resonance Lymphangiography Using Dual-Agent Relaxivity Contrast (DARC-MRL): A Novel Method Combining Gadolinium and Iron Contrast Agents.

The objective of this study was to develop and demonstrate a technique to eliminate venous enhancement in contrast-enhanced magnetic resonance lymphangiography through shortening T2(⁎) in the blood pool, thus allowing for a lymphatic-only map. Administration of the blood-pool iron agent ferumoxtyol in addition to intracutaneous gadolinium during contrast-enhanced magnetic resonance lymphangiography allows for suppression of vascular structures to achieve venous-free lymphatic mapping.

MR lymphangiography: How i do it.

Lymphedema is a chronic progressive edematous disease that in the United States is most commonly related to malignancy and its treatment. Lymphaticovenular anastomosis is a recently introduced microsurgical treatment option for lymphedema that requires the identification and mapping of individual lymphatic channels. While nuclear medicine lymphoscintigraphy has been the primary imaging modality performed to evaluate suspected lymphedema, lymphoscintigraphy does not provide the spatial information necessary for presurgical planning.

Dual energy computed tomography quantification of carotid plaques calcification: comparison between monochromatic and polychromatic energies with pathology correlation.

Purpose: We compared carotid plaque calcification detection sensitivity and apparent cross-sectional area on CT as a function of CT beam energy using conventional CT techniques and virtual mono-energetic CT images generated from dual-energy acquisitions.

Methods & Materials: Five ex-vivo carotid endarterectomy (CEA) specimens were imaged with dual-energy computed tomography. Virtual monochromatic spectrum (VMS) CT images were reconstructed at energies between 40-140 keV.

Computer-assisted evaluation of contrast kinetics for detection of hepatocellular carcinoma on magnetic resonance imaging.

The purpose of this study was to assess the use of semiquantitative contrast-enhanced parameter analysis as an objective criteria for improving the magnetic resonance (MR) evaluation of hepatocellular carcinoma (HCC) in patients with cirrhosis. Contrast-enhanced MR examination findings from 19 patients with 21 pathologically proven HCC were evaluated using a dedicated liver image postprocessing workstation. Contrast-enhancement kinetic curves were created for each lesion, and 4 enhancement parameters (arterial wash-in slope, arterial-portal slope, arterial-equilibrium slope, and portal-equilibrium slope) were defined from the signal intensity-time plots.

Enhancement of the pulmonary arteries and thoracic aorta: comparison of a biphasic contrast injection and fixed delay protocol with a monophasic injection and a timing bolus protocol.

The definitive diagnosis of pulmonary embolism, a significant cause of morbidity and mortality, relies on imaging. In this study, we compare the conventional computed tomography pulmonary angiogram (CTPA) protocol to a double-rule out CT angiogram (DRO CTA) protocol in terms of vascular enhancement, radiation dose, and contrast volume delivered. The CTPA protocol involves injection of a timing bolus for localization of the pulmonary artery, whereas the DRO CTA protocol involves a biphasic contrast.

Standard and reduced radiation dose liver CT images: adaptive statistical iterative reconstruction versus model-based iterative reconstruction-comparison of findings and image quality.

Purpose: To investigate whether reduced radiation dose liver computed tomography (CT) images reconstructed with model-based iterative reconstruction ( MBIR model-based iterative reconstruction ) might compromise depiction of clinically relevant findings or might have decreased image quality when compared with clinical standard radiation dose CT images reconstructed with adaptive statistical iterative reconstruction ( ASIR adaptive statistical iterative reconstruction ).

Materials And Methods: With institutional review board approval, informed consent, and HIPAA compliance, 50 patients (39 men, 11 women) were prospectively included who underwent liver CT. After a portal venous pass with ASIR adaptive statistical iterative reconstruction images, a 60% reduced radiation dose pass was added with MBIR model-based iterative reconstruction images.

Dual-energy liver CT: effect of monochromatic imaging on lesion detection, conspicuity, and contrast-to-noise ratio of hypervascular lesions on late arterial phase.

Objective: The purpose of this study was to evaluate the effect of use of dual-energy CT monochromatic imaging in the late hepatic arterial phase on hyperenhancing focal lesion detection and lesion conspicuity.

Subjects And Methods: This prospective study included 72 patients imaged with a single-source dual-energy CT scanner. Late arterial phase imaging was performed with dual energies of 140 and 80 kVp, and the portal venous and delayed phases were performed with a single energy of 120 kVp.

Comparing the diagnostic accuracy of contrast-enhanced computed tomographic angiography and gadolinium-enhanced magnetic resonance angiography for the assessment of hemodynamically significant transplant renal artery stenosis.

To compare diagnostic accuracy of contrast-enhanced computed tomographic angiography (CTA) and gadolinium-enhanced magnetic resonance angiography (MRA) for the assessment of hemodynamically significant transplant renal artery stenosis (TRAS). After institutional review board approval, records of 27 patients with TRAS confirmed on digital subtraction angiography (DSA) were retrospectively reviewed. A total of 13 patients had MRA and 14 had CTA before DSA.

Magnetic resonance imaging using gadolinium-based contrast agents.

The purpose of this article was to review the basic properties of available gadolinium-based magnetic resonance contrast agents, discuss their fundamental differences, and explore common and evolving applications of gadolinium-based magnetic resonance contrast throughout the body excluding the central nervous system. A more specific aim of this article was to explore novel uses of these gadolinium-based contrast agents and applications where a particular agent has been demonstrated to behave differently or be better suited for certain applications than the other contrast agents in this class.

Minimal aortic injury of the thoracic aorta: imaging appearances and outcome.

The aim of this study is to describe the frequency, computed tomographic angiography (CTA) imaging appearance, management, and outcome of patients who present with minimal thoracic aortic injury. This retrospective study was Institutional Review Board-approved. Eighty-one patients with blunt traumatic aortic injuries (BTAI) were identified between 2004 and 2008, comprising 23 patients with minimal aortic injury (MAI) (mean age, 43.

Cardiac complications of oncologic therapy.

As survival rates continue to increase for patients with childhood and adult malignancies, imaging utilization in these patients will likely increase substantially. It is important to detect disease recurrence and to recognize the potential complications that occur after treatment with oncologic medications and therapeutic radiation. The most common cardiotoxic side effect of the anthracycline drug class is a dose-dependent decline in ejection fraction, which may result in dilated cardiomyopathy.

Evaluating contrast agent waste and costs of weight-based CT contrast bolus protocols using single- or multiple-dose packaging.

Objective: Although weight-based contrast agent injection protocols can improve contrast-enhanced CT, one disadvantage is waste caused by differences between the amount of contrast material required for a weight-based algorithm and full-package protocols used with single-use packaging of contrast material. The availability of 500-mL multiple-use packaging of contrast material should facilitate the implementation of weight-based contrast bolus protocols for CT because arbitrary volumes of contrast agent can be loaded without significant waste. Our hypothesis was that multiple-use packaging when used with a weight-based contrast bolus protocol would reduce costs compared with single-use packaging.

Diagnostic performance of resting CT myocardial perfusion in patients with possible acute coronary syndrome.

Objective: Coronary CT angiography has high sensitivity, but modest specificity, to detect acute coronary syndrome. We studied whether adding resting CT myocardial perfusion imaging improved the detection of acute coronary syndrome.

Subjects And Methods: Patients with low-to-intermediate cardiac risk presenting with possible acute coronary syndrome received both the standard of care evaluation and a research thoracic 64-MDCT examination.

Model-based iterative reconstruction versus adaptive statistical iterative reconstruction and filtered back projection in liver 64-MDCT: focal lesion detection, lesion conspicuity, and image noise.

Objective: The purpose of this study is to compare three CT image reconstruction algorithms for liver lesion detection and appearance, subjective lesion conspicuity, and measured noise.

Materials And Methods: Thirty-six patients with known liver lesions were scanned with a routine clinical three-phase CT protocol using a weight-based noise index of 30 or 36. Image data from each phase were reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR).

Diagnostic accuracy and clinical outcomes of ECG-gated, whole chest CT in the emergency department.

Purpose: The purpose of this study was to assess the diagnostic accuracy and one year prognosis of whole chest, "multiple rule out" CT for coronary artery disease (CAD) in Emergency Department patients.

Methods And Findings: One hundred and two Emergency Department patients at low to intermediate risk of acute coronary syndrome (ACS), pulmonary embolism and/or acute aortic syndrome underwent a research 64 channel ECG-gated, whole chest CT and a standard of care evaluation. Patients were classified with obstructive CAD with either a coronary CT stenosis greater than 50% or a non-evaluable coronary segment.

Prospective comparison of valve regurgitation quantitation by cardiac magnetic resonance imaging and transthoracic echocardiography.

Background: Both transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging allow quantification of chronic aortic regurgitation (AR) and mitral regurgitation (MR). We hypothesized that CMR measurement of regurgitant volume (RVol) is more reproducible than TTE.

Methods And Results: TTE and CMR performed on the same day in 57 prospectively enrolled adults (31 with AR, 26 with MR) were measured by 2 independent physicians.

Challenges to protocol optimization due to unexpected variation of CT contrast dose amount and flow.

High-quality computed tomography (CT) exams are critical to maximizing radiologist's interpretive ability. Exam quality in part depends on proper contrast administration. We examined injector data from consecutive abdominal and pelvic CT exams to analyze variation in contrast administration.

Changes in measured size of atherosclerotic plaque calcifications in dual-energy CT of ex vivo carotid endarterectomy specimens: effect of monochromatic keV image reconstructions.

Objective: The aim of this study was to compare the size of the calcifications measured on the different keV images to a histological standard.

Methods: Five ex vivo carotid endarterectomy (CEA) specimens were imaged with a dual-energy CT. CT images were reconstructed at different monochromatic spectral energies (40, 60, 77, 80, 100, 120, 140 keV).