Prostate cancer metastasis to calcaneus: a solitary lesion at an atypical site, dormant for more than 10 years.

In prostate cancer patients, if bone scan demonstrates a solitary lesion in atypical area, this is possibly an indication of metastatic disease. Therefore, biopsy confirmation is required to determine the nature of the abnormality and therefore dictates further staging investigations and treatment options.

Remote ischemic conditioning and renal function after contrast-enhanced CT scan: A randomized trial.

PURPOSE: Remote ischemic conditioning has been shown to protect against kidney injury in animal and human studies of ischemia-reperfusion. Recent evidence suggests that conditioning may also provide protection against kidney injury caused by contrast medium. The purpose of this study was to determine if conditioning protected against increases in serum creatinine (SCr) after contrast-enhanced computed tomography (CECT). METHODS: A randomised controlled trial (NCT 01741896) was performed with institutional review board approval and informed patient consent. Adult in-patients undergoing abdomino-pelvic CECT were allocated to conditioned or control groups. Conditioning consisted of four cycles of five minutes of cuff-induced arm ischemia with three minutes of reperfusion applied ~40 minutes before CECT. The primary outcome was SCr change after CECT. RESULTS: Baseline characteristics were similar in both groups. For all patients, conditioning reduced the risk ratio (RR) of increased SCr; RR 0.65 (95% confidence intervals 0.41 to 1.04). The protective effect was greater and the evidence for protection stronger when analysis was restricted to patients with pre-scan reduced renal function (eGFR.

Fibrosing interstitial lung disease. A practical high-resolution computed tomography-based approach to diagnosis and management and a review of the literature.

Establishing the etiology of fibrosing interstitial lung disease (FILD) remains a clinical challenge. This is because many disorders resulting in lung fibrosis may be similar in their initial clinical and radiographic appearances. High-resolution computed tomography (HRCT) studies are now almost always obtained for patients who present with otherwise nonspecific clinical symptoms and chest radiographic findings. In the majority of cases presenting with FILD, differential diagnosis typically requires differentiating among three most commonly encountered clinical entities: idiopathic pulmonary fibrosis with usual interstitial pneumonia, nonspecific interstitial pneumonia, and chronic hypersensitivity pneumonitis. As a consequence, the development of a simplified diagnostic algorithmic approach initially focusing on the interpretation of HRCT findings may prove of considerable value provided thorough familiarity with optimal HRCT techniques and methods of interpretation. For this purpose, in patients with FILD in whom an underlying etiology is not initially apparent, the recently proposed American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association guidelines for the diagnosis of IPF have been modified to create a straightforward, clinically practicable algorithmic approach to clinical management based on the initial interpretation and classification of HRCT findings.

Stimulated echo diffusion tensor imaging and SPAIR T2 -weighted imaging in chronic exertional compartment syndrome of the lower leg muscles.

PURPOSE: To evaluate the performance of diffusion tensor imaging (DTI) in the evaluation of chronic exertional compartment syndrome (CECS) as compared to T2 -weighted (T2w) imaging. MATERIALS AND METHODS: Using an Institutional Review Board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant protocol, spectral adiabatic inversion recovery (SPAIR) T2w imaging and stimulated echo DTI were applied to eight healthy volunteers and 14 suspected CECS patients before and after exertion. Longitudinal and transverse diffusion eigenvalues, mean diffusivity (MD), and fractional anisotropy (FA) were measured in seven calf muscle compartments, which in patients were classified by their response on T2w: normal (<20% change), and CECS (>20% change). Mixed model analysis of variance compared subject groups and compartments in terms of response factors (post/pre-exercise ratios) of DTI parameters. RESULTS: All diffusivities significantly increased (P < 0.0001) and FA decreased (P = 0.0014) with exercise. Longitudinal diffusion responses were significantly smaller than transversal diffusion responses (P < 0.0001). Nineteen of 98 patient compartments were classified as CECS on T2w. MD increased by 3.8 ± 3.4% (volunteer), 7.4 ± 4.2% (normal), and 9.1 ± 7.0% (CECS) with exercise. CONCLUSION: DTI shows promise as an ancillary imaging method in the diagnosis and understanding of the pathophysiology in CECS. Future studies may explore its utility in predicting response to treatment.

Comparison of nonenhanced MR angiographic subtraction techniques for infragenual arteries at 1.5 T: a preliminary study.

PURPOSE: To evaluate diagnostic performance of three nonenhanced methods: variable-refocusing-flip angle (FA) fast spin-echo (SE)-based magnetic resonance (MR) angiography (variable FA MR) and constant-refocusing-FA fast SE-based MR angiography (constant-FA MR) and flow-sensitive dephasing (FSD)-prepared steady-state free precession MR angiography (FSD MR) for calf arteries, with dual-injection three-station contrast material-enhanced MR angiography (gadolinium-enhanced MR) as reference. MATERIALS AND METHODS: This prospective study was institutional review board approved and HIPAA compliant, with informed consent. Twenty-one patients (13 men, eight women; mean age, 62.6 years) underwent calf-station variable-FA MR, constant-FA MR, and FSD MR at 1.5 T, with gadolinium-enhanced MR as reference. Image quality and stenosis severity were assessed in 13 segments per leg by two radiologists blinded to clinical data. Combined constant-FA MR and FSD MR reading was also performed. Methods were compared (logistic regression for correlated data) for diagnostic accuracy. RESULTS: Of 546 arterial segments, 148 (27.1%) had a hemodynamically significant (≥ 50%) stenosis. Image quality was satisfactory for all nonenhanced MR sequences. FSD MR was significantly superior to both other sequences (P < .0001), with 5-cm smaller field of view; 9.6% variable-FA MR, 9.6% constant-FA MR, and 0% FSD MR segmental evaluations had nondiagnostic image quality scores, mainly from high diastolic flow (variable-FA MR) and motion artifact (constant-FA MR). Stenosis sensitivity and specificity were highest for FSD MR (80.3% and 81.7%, respectively), compared with those for constant-FA MR (72.3%, P = .086; and 81.8%, P = .96) and variable-FA MR (75.9%, P = .54; and 75.6%, P = .22). Combined constant-FA MR and FSD MR had superior sensitivity (81.8%) and specificity (88.3%) compared with constant-FA MR (P = .0076), variable-FA MR (P = .0044), and FSD MR (P = .0013). All sequences had an excellent negative predictive value (NPV): 93.2%, constant-FA MR; 94.7%, variable-FA MR; 91.7%, FSD MR; and 92.9%, combined constant-FA MR and FSD MR. CONCLUSION: At 1.5 T, all evaluated nonenhanced MR angiographic methods demonstrated satisfactory image quality and excellent NPV for hemodynamically significant stenosis. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120859/-/DC1.

Evaluation and management of indeterminate pulmonary nodules.

The radiologic evaluation and management of the indeterminate solitary pulmonary nodule provide common diagnostic dilemma. With continued technologic advancements in multidetector computed tomography leading to higher spatial resolution and greater overall sensitivity of computed tomography scanners, increasing numbers of indeterminate solitary pulmonary nodules are being detected. Malignant and benign solitary pulmonary nodules have similar imaging features. Clinical management of these incidental nodules relies not only on imaging characteristics but also on malignancy risk factors, along with the risks and benefits of further investigation.

Inline directionally independent peak velocity evaluation reduces error in peak antegrade velocity estimation in patients referred for cardiac valvular assessment.

OBJECTIVE: The purpose of this article is to evaluate the utility of a tool in quantifying the peak antegrade velocity when assessing patients with cardiac valvular pathology. MATERIALS AND METHODS: Directionally independent peak velocity evaluation (MaxVelocity, Siemens Healthcare) phase-contrast cardiac MRI was performed for 44 patients referred to our institution with a diagnosis or concern for aortic valvular disease or undergoing imaging for thoracic aortic aneurysm. In addition, standard through-plane phase-contrast MR angiography at the level of the aortic valve was performed. The MaxVelocity technique provides a simple tool to extract the magnitude of the peak velocity, independently of its direction, from phase-contrast imaging with velocity encoding. Recent echocardiography (within 1 month) and assessment of peak forward velocity at the level of the aortic valve were required for inclusion in the study. RESULTS: The MaxVelocity technique shows significantly lower error in estimating peak antegrade velocity at the level of the aortic valve than does standard unidirectional through-plane phase-contrast MRI, using transthoracic echocardiography as the reference noninvasive imaging method. CONCLUSION: Relative to standard through-plane imaging, MaxVelocity more closely approximates echocardiography for noninvasive assessment of peak antegrade velocity. Improved accuracy is critical for surgical decision making in patients with aortic valvular disease. Therefore, MaxVelocity provides an easy approach to quantify peak velocity as part of a routine clinical MRI protocol.

Peripheral arterial disease in a symptomatic diabetic population: prospective comparison of rapid unenhanced MR angiography (MRA) with contrast-enhanced MRA.

OBJECTIVE: The joint guidelines of the American College of Cardiology and American Heart Association support the use of contrast-enhanced MR angiography (CEMRA) to diagnose the location and degree of stenosis in patients with known or suspected peripheral arterial disease (PAD). The high prevalence of chronic renal impairment in diabetic patients with PAD and the need for high doses of gadolinium-based contrast agents place them at risk for nephrogenic systemic fibrosis. The purpose of our study was to evaluate the accuracy of the rapid technique of quiescent-interval single-shot (QISS) unenhanced MR angiography (MRA) compared with CEMRA for the diagnosis in diabetic patients referred with symptomatic chronic PAD. SUBJECTS AND METHODS: This prospective two-center study evaluated 25 consecutive diabetic patients with documented or suspected symptomatic PAD. Both centers used identical imaging protocols. Images were independently analyzed by two radiologists. A subgroup analysis was performed of patients who were also assessed with digital subtraction angiography (DSA) as part of the standard-of-care protocol before revascularization. RESULTS: For this study, 775 segments were analyzed. On a per-segment basis, the mean values of the diagnostic accuracy of unenhanced MRA compared with reference CEMRA for two reviewers, reviewers 1 and 2, were as follows: sensitivity, 87.4% and 92.1%; specificity, 96.8% and 96.0%; positive predictive value, 90.8% and 94.0%; and negative predictive value, 95.5% and 94.6%. Substantial agreement was found when overall DSA results were compared with QISS unenhanced MRA (κ = 0.68) and CEMRA (κ = 0.63) in the subgroup of patients who also underwent DSA. There was almost perfect agreement between the two readers for stenosis scores, with Cohen's kappa values being greater than 0.80 for both MRA techniques. CONCLUSION: The results of our study indicate that QISS unenhanced MRA is an accurate noncontrast alternative to CEMRA for showing clinically significant arterial disease in patients with diabetes with symptomatic PAD.

MDCT bolus tracking data as an adjunct for predicting the diagnosis of pulmonary hypertension and concomitant right-heart failure.

OBJECTIVE: The purpose of this study was to investigate the utility of bolus-triggering data from pulmonary CT angiography for predicting the diagnosis of pulmonary hypertension (PH) and right ventricular dysfunction (RVD) and to test its performance against previously established CT signs of PH. MATERIALS AND METHODS: Automated bolus-triggering data from pulmonary CT angiograms of 101 patients were correlated with echocardiographic findings and a variety of CT-derived indexes of PH and RVD, including right and left ventricular minor axis diameter; pulmonary artery (PA), aortic, and superior vena caval diameters; right ventricular thickness; contrast reflux; and configuration of the interventricular septum. For bolus triggering, a region of interest was placed in the main PA. Time to threshold, defined as the time from the beginning of contrast injection to the time attenuation exceeded the threshold (100 HU), was measured. On the basis of results of two consecutive echocardiographic studies, subjects were divided into control and PH groups. The latter group was subdivided into PH without RVD and PH with RVD. Time to threshold values were compared between groups and correlated with standard CT-derived parameters. RESULTS: Significant differences between groups were found in time to threshold, PA and right ventricular diameters, and PA-to-aorta and right ventricular-to-left ventricular ratios. Time to threshold had an incremental pattern from the control group (6.6 ± 1.0 seconds) to PH without RVD (9.2 ± 2.4 seconds) and PH with RVD (12.1 ± 3.4 seconds) (p < 0.001). The optimal diagnostic performance of time to threshold for revealing the presence of PH and RVD was at cutoff values of 7.75 and 8.75 seconds, respectively. Time to threshold had a strong direct correlation with PA diameter. In multivariable analyses, time to threshold was identified as a significant predictor of PH and RVD. The specificity of time to threshold and PA diameter together was higher than that of PA diameter alone. CONCLUSION: Measurement of time to threshold of contrast enhancement derived from bolus-timing data at MDCT may be a useful adjunctive tool for diagnosing PH and consequent RVD.

Noncontrast magnetic resonance angiography of the hand: improved arterial conspicuity by multidirectional flow-sensitive dephasing magnetization preparation in 3D balanced steady-state free precession imaging.

PURPOSE: : To develop a flow-sensitive dephasing (FSD) preparative scheme to facilitate multidirectional flow-signal suppression in 3-dimensional balanced steady-state free precession imaging and to validate the feasibility of the refined sequence for noncontrast magnetic resonance angiography (NC-MRA) of the hand. MATERIALS AND METHODS: : A new FSD preparative scheme was developed that combines 2 conventional FSD modules. Studies using a flow phantom (gadolinium-doped water 15 cm/s) and the hands of 11 healthy volunteers (6 males and 5 females) were performed to compare the proposed FSD scheme with its conventional counterpart with respect to the signal suppression of multidirectional flow. In 9 of the 11 healthy subjects and 2 patients with suspected vasculitis and documented Raynaud phenomenon, respectively, 3-dimensional balanced steady-state free precession imaging coupled with the new FSD scheme was compared with spatial-resolution-matched (0.94 × 0.94 × 0.94 mm) contrast-enhanced magnetic resonance angiography (0.15 mmol/kg gadopentetate dimeglumine) in terms of overall image quality, venous contamination, motion degradation, and arterial conspicuity. RESULTS: : The proposed FSD scheme was able to suppress 2-dimensional flow signal in the flow phantom and hands and yielded significantly higher arterial conspicuity scores than the conventional scheme did on NC-MRA at the regions of common digitals and proper digitals. Compared with contrast-enhanced magnetic resonance angiography, the refined NC-MRA technique yielded comparable overall image quality and motion degradation, significantly less venous contamination, and significantly higher arterial conspicuity score at digital arteries. CONCLUSION: : The FSD-based NC-MRA technique is improved in the depiction of multidirectional flow by applying a 2-module FSD preparation, which enhances its potential to serve as an alternative magnetic resonance angiography technique for the assessment of hand vascular abnormalities.

Evaluation of peripheral arterial disease with nonenhanced quiescent-interval single-shot MR angiography.

PURPOSE: To assess the diagnostic performance of quiescent-interval single-shot (QISS) magnetic resonance (MR) angiography, a nonenhanced two-dimensional electrocardiographically gated single-shot balanced steady-state free precession examination for the evaluation of symptomatic chronic lower limb ischemia. MATERIALS AND METHODS: For this prospective institutional review board-approved, HIPAA-compliant study, the institutional review board waived the requirement for informed patient consent. The QISS nonenhanced MR angiography technique was evaluated in a two-center trial involving 53 patients referred for lower extremity MR angiography for suspected or known chronic peripheral arterial disease (PAD), with contrast material-enhanced MR angiography serving as the noninvasive reference standard. The accuracy of stenosis assessments performed with the nonenhanced MR angiography sequence was evaluated relative to the reference standard. Per-segment, per-region, and per-limb sensitivities and specificities were calculated, and assessments were considered correct only if they were in exact agreement with the reference standard-derived assessments. Generalized estimating equation (GEE) modeling with use of an unstructured binomial logit analysis was used to account for clustering of multiple measurements per case. The sensitivity and specificity of QISS MR angiography for the determination of nonsignificant (<50%) versus significant (50%-100%) stenosis were compared with the sensitivity and specificity of the reference standard. RESULTS: The diagnostic performance of nonenhanced MR angiography was found to be nearly equivalent to the diagnostic performances of contrast-enhanced MR angiography and digital subtraction angiography. Non-GEE segment-based analysis revealed that for the two reviewers, nonenhanced MR angiography had sensitivities of 89.7% (436 of 486 segments) and 87.0% (423 of 486 segments) and specificities of 96.5% (994 of 1030 segments) and 94.6% (973 of 1028 segments). CONCLUSION: QISS nonenhanced MR angiography offers an alternative to currently used imaging tests for symptomatic chronic lower limb ischemia, for which the administration of iodinated or gadolinium-based contrast agents is contraindicated.

Nonenhanced MR angiography of the hand with flow-sensitive dephasing-prepared balanced SSFP sequence: initial experience with systemic sclerosis.

PURPOSE: To compare the image quality and degree of vessel narrowing at flow-sensitive dephasing (FSD) magnetic resonance (MR) angiography of the hands with those at contrast material-enhanced MR angiography of the hands in patients with systemic sclerosis. MATERIALS AND METHODS: In a single-center study with institutional review board approval and HIPAA compliance, six healthy volunteers and six patients with systemic sclerosis were imaged at 1.5-T nonenhanced FSD MR angiography followed by contrast-enhanced MR angiography. Sixteen vascular segments in four vessel groups were evaluated for image quality and assessed semiquantitatively for stenosis degree by using Likert scales. The nonparametric Wilcoxon signed rank test was used to perform pairwise comparisons of the MR angiographic techniques. P < .05 indicated statistical significance. RESULTS: Performing FSD MR angiography, as compared with time-resolved MR angiography and high-spatial-resolution MR angiography, improved the image quality for all arterial segments combined in the control (mean score, 2.9 [FSD] vs 3.7 [time-resolved technique] and 3.1 [high-spatial-resolution technique]) and patient (mean score, 4.0 [FSD] vs 4.2 [time-resolved technique] and 4.3 [high-spatial-resolution technique]) groups. In the control subjects, FSD angiography depicted proper digital artery stenosis that was less severe (mean grade, 0.7) than that seen with the time-resolved (mean grade, 1.6) and high-spatial-resolution (mean grade, 1.0) techniques. In the patient group, FSD angiography depicted lower degrees of stenosis, with a lower mean grade for all segments combined (1.3) compared with the corresponding mean grades for time-resolved (1.5) and high-spatial-resolution (1.8) MR angiography. CONCLUSION: Preliminary data indicate that the proposed nonenhanced FSD MR angiographic technique is an improvement over existing contrast-enhanced techniques for evaluation of the hand vasculature in vasospastic disorders of the hand. Further technical improvements and a systematic clinical study are warranted.

Nonenhanced methods for lower-extremity MRA: a phantom study examining the effects of stenosis and pathologic flow waveforms at 1.5T.

PURPOSE: To evaluate the signal properties of 2D time of flight (TOF), quiescent-interval single-shot (QISS), ECG-gated 3D fast spin-echo (FBI), and ungated 3D fast spin-echo ghost (Ghost) magnetic resonance angiography (MRA) over a range of flow velocities in a pulsatile flow phantom with a 50% diameter stenosis at 1.5T. MATERIALS AND METHODS: Blood-mimicking fluid was pumped at eight peak flow velocities through a stenotic region in triphasic and monophasic waveforms. Vascular signal proximal, within, and distal to the stenosis was measured from the source images of the four MRA methods. Coronal maximum intensity projection images were used to compare image quality. RESULTS: TOF and QISS signal trends were similar, but QISS exhibited the most consistent signal across velocities. At high velocities (≥ 42.4 cm/s), TOF showed poststenotic signal loss that was not observed with QISS. FBI and Ghost signals peaked at low velocities (3.9-9.7 cm/s) without flow compensation and at high velocities (≥ 64.6 cm/s) with flow compensation. CONCLUSION: FBI and Ghost demonstrated dependence on blood flow velocity and flow compensation. TOF was sensitive to flow artifacts at high velocities. QISS proved most robust for accurately depicting the normal lumen and stenosis under a wide range of flow conditions. Monophasic and triphasic flow did not appreciably affect the signal performance of any method.

MR imaging of overuse injuries of the hip.

The aim of this article is to emphasize the importance of MR imaging in the evaluation of chronic hip pain and overuse injuries. Image interpretation of the hip can be difficult because of the complex anatomy and the varied pathology that athletes can present with, such as labral and cartilaginous injuries, surrounding soft tissue derangement involving muscles or tendons, and osseous abnormalities. The differential diagnosis in adults is diverse and includes such common entities as stress fracture, avulsive injuries, snapping-hip syndrome, iliopsoas bursitis, femoroacetabular impingement syndrome, tendinosis, and tears of the gluteal musculature.

MR imaging of muscle injury.

Although most muscle injuries in the athlete are diagnosed clinically, MR imaging is an excellent noninvasive diagnostic adjunct to clinical examination, which allows the site and severity of muscle injury to be assessed accurately, influencing therapy and overall outcome. There has been a rapid expansion in the clinical use of MR imaging during the past decade. MR imaging conveys unparalleled anatomic resolution and high sensitivity in the detection of acute and chronic muscle abnormalities. This article discusses the spectrum of muscle injuries, emphasizing the important role of MR imaging in their diagnosis and management.

Imaging of gastrointestinal and hepatic diseases during pregnancy.

Imaging of the abdomen for suspected gastrointestinal and hepatic disease during pregnancy is assuming greater importance. Like clinical evaluation, imaging of the abdomen and pelvis is challenging but is vitally important to prevent delayed diagnosis or unnecessary interventions. Also choice of imaging modality is influenced by factors which could impact on fetal safety such as the use of ionising radiation and magnetic resonance imaging. This article discusses important issues in imaging of gastrointestinal and hepatic disease in pregnancy and the puerperium.

Evidence-based Practice in Radiology: steps 3 and 4--appraise and apply interventional radiology literature.

When introducing new interventional radiology techniques or devices, it is important to learn from previous experiences and to remember that there are numerous examples of new techniques that were initially enthusiastically promoted and then subsequently abandoned when early promise was not realized. Appropriateness of new or established interventional radiology techniques to specific clinical conditions must be determined from clinical experience, from communication with experts in the field and/or careful review of available medical literature, and on an individual patient basis by means of review of clinical notes and diagnostic imaging studies. Several paradigms for evidence-based practice (EBP) exist. One model proposes that a central specialized process involving academic centers should primarily construct valid guidelines to direct practice at all levels of medical practice ("top-down" model). An alternative model integrates "the best research evidence with clinical expertise and patient values" ("bottom-up" model). This article will focus on the bottom-up model and describe the use of EBP by individual practitioners or groups of practitioners in optimizing literature review and critical appraisal. EBP is applied to two scenarios as a means of deciding the appropriateness of introducing interventional radiology techniques in a community hospital setting. The authors will also briefly discuss other applications for EBP techniques in interventional radiology, including development of practice guidelines or policy to ensure appropriate and safe practices.