Micro magnetic resonance angiography of the finger in systemic sclerosis

Performance of finger systolic blood pressure measurement to detect digital occlusive arterial disease in systemic sclerosis

OBJECTIVE

Digital ulcers (DUs) related to digital occlusive arterial disease (DOAD) are frequent in patients with systemic sclerosis (SSc). Finger systolic blood pressure (FSBP) and digital-brachial pressure index (DBI) using laser Doppler flowmetry constitute a non-invasive means of detecting DOAD in SSc, although thresholds have yet to be established for defining DOAD. The purpose of this study was to ascertain FSBP and DBI thresholds to detect DOAD in SSc patients. The intra/interday reproducibility of curve reading by 4 vascular physicians in relation to finger pressure measurement was also investigated.

METHODS

SSc patients were followed in this single-center study (Rennes University Hospital, France) between November 2017 and October 2019.Theses patients underwent tests before and after heating at two visits spaced 10 days apart. DOAD was diagnosed on the basis of post-warming skin blood flow of ≤ 206 arbitrary units measured by LDF, contingent on previous results validated by arteriography as a gold standard. An interday kappa coefficient with a 95% confidence interval was used to assess reproducibility.

RESULTS

16 (10 females; mean age: 63 ± 9 years) SSc patients were included. Mean time interval between visits was 9 ± 5 days. The best FSBP threshold for DOAD diagnosis was 76 mmHg and DBI was 0.74 after warming. FSBP and DBI sensitivity/specificity were 59.1%[49.6%; 68.5%]/92.5% [85.3%; 99.6%] and 73.3%[64.9%; 81.8%]/83.0% [72.9%; 93.1%] respectively. Intra/interday reproducibility ranged from fair to good.

CONCLUSION

The conclusions drawn from this study suggest that FSBP ≤ 76 mmHg and DBI ≤ 0.74 thresholds are potentially reliable indicators of DOAD and demonstrate fair to good intra and interday reproducibility.

A narrative review of imaging in calcinosis associated with systemic sclerosis

Calcinosis is dystrophic calcification of the soft tissue which can lead to painful and debilitating disease. It is commonly seen in patients with systemic sclerosis (SSc). Imaging can assist in diagnosis, quantification of disease, and better pathophysiologic understanding of calcinosis. Traditionally, X-rays have been the most frequently used imaging modality for diagnosis; however, advances in ultrasound (US), computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) have led to greater ability to characterize these lesions and surrounding structures. This narrative review aims to describe the use of imaging for calcinosis in patients with SSc. Key Points • Imaging is useful in the diagnosis of calcinosis, assessment of disease severity, and disease monitoring. • X-ray is commonly used and offers high sensitivity and specificity, but both ultrasound and CT-scans are alternatives when greater anatomic detail is sought regarding surrounding structures. • Investigational imaging modalities include dual energy CT-scans, cinematic rendering CT-scans, and PET- CT scans. • Conventional MRI scans have less sensitivity and specificity for detection of calcinosis.

Noncontrast Magnetic Resonance Angiography in the Era of Nephrogenic Systemic Fibrosis and Gadolinium Deposition

ABSTRACT

Gadolinium-based contrast agents for clinical magnetic resonance imaging are overall safe. However, the discovery of nephrogenic systemic fibrosis in patients with severe renal impairment and gadolinium deposition in patients receiving contrast have generated developments in contrast-free imaging of the vasculature, that is, noncontrast magnetic resonance angiography. This article presents an update on noncontrast magnetic resonance angiography techniques, with comparison to other imaging alternatives. Potential benefits and challenges to implementation, and evidence to date for various clinical applications are discussed.

Biomarkers as an opportunity to stratify for outcome in systemic sclerosis

Systemic sclerosis (SSc) is a highly complex disease whose heterogeneity includes multiple aspects of the condition, such as clinical presentation, progression, extent and type of organ involvement, and clinical outcomes. Thus far, these features remain not easily predictable both at the patient group level and in a given patient with regard to age at onset and clinical course. The unpredictable clinical course represents an obstacle to focusing potentially effective treatment in patients that need it the most. At the time of organ involvement and clinical diagnosis, most of the clinical manifestations are irreversible; therefore, predicting outcomes becomes crucial. This can explain the multiple attempts to identify prognostic, predictive, and monitoring-both soluble and imaging-biomarkers over the past years. They range from the currently most used biomarkers, the autoantibodies associated with disease-specific clinical features and course, to the single recently proposed skin, lung, cardiac involvement biomarkers and to the composite scores capturing multiple aspects of the disease. This review will focus on soluble and imaging biomarkers that recently showed promising evidence for outcome stratification in patients with SSc.

Imaging digital arteries in systemic sclerosis by tomographic 3-dimensional ultrasound

Objective methods are needed to quantify digital artery disease in systemic sclerosis (SSc) for clinical trials of vascular therapies. Our primary aim was to examine feasibility of a novel tomographic three-dimensional-(3-D) ultrasound (tUS) with high-frequency ultrasound (HFUS) or ultra-high-frequency ultrasound (UHFUS) to assess the digital arteries in patients with SSc compared to healthy controls. A secondary objective was to compare the total wall volume (TWV) as a measure of intimal/medial thickness. Eighteen patients with a confirmed diagnosis of SSc were studied by tUS HFUS (17.5 MHz, n = 10) or tUS UHFUS (48 and 70 MHz, n = 8) with equal numbers of healthy controls of similar age and gender. The majority of patients had limited cutaneous SSc and were representative of a spectrum of digital vasculopathy, with over half (n = 6 HFUS and n = 5 UHFUS) having previous digital ulceration. Over half were receiving oral vasodilatory therapy. TWV was measured in both digital arteries of the middle finger bilaterally. At least, two digital arteries could be identified at 17.5 MHz in all patients and healthy controls. Whereas, at least two digital arteries could be identified in relatively fewer patients compared to healthy controls using 48 MHz (n = 6 and 10) and especially 70 MHz (n = 4 and 10) UHFUS. The median difference in TWV between patients and healthy controls was -6.49 mm³ using 17.5 MHz, 1.9 mm³ at 48 MHz, and -0.4 mm³ at 70 MHz. tUS using UHFUS is a feasible method to measure TWV of digital arteries in SSc. Transducer frequency plays an important factor in successful digital artery measurement, with 48 MHz being the optimal frequency.

Design and fabrication of a new multi-loop saddle coil for 1.5 T MRI

Radiofrequency coils provide high-resolution magnetic resonance (MR) imaging of human tissues. A small RF coil produces MR images with a higher resolution compared to the commercial volume MR coils from mass limited samples. Signal to noise ratio (SNR) plays a key role in the optimal design of receiver radiofrequency coils. In this work, we present a three-loop saddle coil suitable for MR imaging of digits of the human body. The geometry of the introduced coil is optimized to achieve the highest SNR. The coil performance is evaluated through comparing the measured SNR maps of the optimal coil derived from MR images of a saline phantom with the corresponding measured SNR maps of a commercial head coil in axial and sagittal slices. Results verify that the image SNR of the introduced coil is 3.4 times higher than that of the head coil and 2 times higher than that of the similar saddle coils represented in the literature recently. To validate the measured results, SNR maps of the introduced saddle and head coils were simulated and their SNR difference was compared with the corresponding measured data of the two coils. Results show that the simulated and measured data are in agreement with less than 11.8% error.

CT and MR imaging of the upper extremity vasculature: pearls, pitfalls, and challenges

Imaging is needed for diagnosis, treatment planning, and follow-up of patients with pathologies affecting upper extremity vasculature. With growth and evolution of imaging modalities [especially CT angiography (CTA) and MR angiography (MRA)], there is need to recognize the advantages and disadvantages of various modalities and obtain the best possible imaging diagnostic test. Understanding various limitations and pitfalls as well as the best practices to minimize and manage these pitfalls is very important for the diagnosis. This article reviews the upper extremity arterial vascular anatomy, discusses the CTA and MRA imaging, various pitfalls, and challenges and discuss imaging manifestations of upper extremity arterial pathologies.

[Acute aortic diseases. Diagnostic imaging and therapy]

Diagnostic imaging is crucial in the work-up of acute aortic diseases. Current imaging algorithms enable radiologists differentiating the various entities with subsequent clinically relevant treatment options. Within this educational overview we focus on non-traumatic acute aortic disease. Recent developments of cross sectional imaging are summarized. As for acute aortic disease, we discuss dissections, intramural hematoma, penetrating aortic ulcer, and aortitis. Current treatment options are presented.

Simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging for carotid atherosclerotic disease evaluation

A simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) MR imaging technique is proposed to detect both luminal stenosis and hemorrhage in atherosclerosis patients in a single scan. Thirteen patients with diagnosed carotid atherosclerotic plaque were admitted after informed consent. All scans were performed on a 3T MR imaging system with SNAP, 2D time-of-flight and magnetization-prepared 3D rapid acquisition gradient echo sequences. The SNAP sequence utilized a phase sensitive acquisition, and was designed to provide positive signals corresponding to intraplaque hemorrhage and negative signals corresponding to lumen. SNAP images were compared to time-of-flight images to evaluate lumen size measurements using linear mixed models and the intraclass correlation coefficient. Intraplaque hemorrhage identification accuracy was evaluated by comparing to magnetization-prepared 3D rapid acquisition gradient echo images using Cohen's Kappa. Diagnostic quality SNAP images were generated from all subjects. Quantitatively, the lumen size measurements by SNAP were strongly correlated (intraclass correlation coefficient = 0.96, P < 0.001) with those measured by time-of-flight. For intraplaque hemorrhage detection, strong agreement (κ = 0.82, P < 0.001) was also identified between SNAP and magnetization-prepared 3D rapid acquisition gradient echo images. In conclusion, a SNAP imaging technique was proposed and shows great promise for imaging both lumen size and carotid intraplaque hemorrhage with a single scan.

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.

The impact of Fli1 deficiency on the pathogenesis of systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune inflammatory disease with unknown etiology characterized by microvascular injury and fibrosis of the skin and internal organs. A growing body of evidence suggests that deficiency of the transcription factor Fli1 (Friend leukemia integration-1) has a pivotal role in the pathogenesis of SSc. Fli1 is expressed in fibroblasts, endothelial cells, and immune cells, and has important roles in the activation, differentiation, development, and survival of these cells. Previous studies demonstrated that Fli1 is downregulated in SSc fibroblasts by an epigenetic mechanism and a series of experiments with Fli1-deficient animal models revealed that Fli1 deficiency in fibroblasts and endothelial cells reproduces the histopathologic features of fibrosis and vasculopathy in SSc, respectively. In this article, we review the impact of Fli1 deficiency on the pathogenesis of SSc and discuss a new therapeutic strategy for SSc by targeting the transcription factor Fli1.

High-resolution uniform MR imaging of finger joints using a dedicated RF coil at 3T

PURPOSE

To develop a dedicated radiofrequency (RF) coil for high-resolution magnetic resonance imaging (MRI) of finger joints at 3T to improve diagnostic evaluation of arthritic diseases.

MATERIALS AND METHODS

A dedicated cylindrical RF receive coil was developed for imaging finger joints at 3T. A planar coil, a saddle coil, and a 1.5T coil with similar design as the dedicated coil were also constructed to compare imaging performance with the dedicated coil. A phantom was used for quantitative evaluation. Three-dimensional images were obtained on four subjects and a cadaver finger specimen using isotropic resolution of 160 mum in 9:32 minutes. The images were reviewed by two musculoskeletal radiologists.

RESULTS

The dedicated finger coil provided higher signal-to-noise and greater signal uniformity than the other coils. It supported high-resolution imaging that demonstrated anatomical details of the entire finger joint, and in the subject study revealed abnormalities not detectable by traditional clinical resolution.

CONCLUSION

The dedicated finger coil optimizes the potential advantages of 3T scanners compared to lower field magnets. Use of this coil should facilitate early diagnosis, improve assessment of treatment response, and provide better understanding of basic mechanisms that underlie arthritis.

Three-dimensional electrocardiographically gated variable flip angle FSE imaging for MR angiography of the hands at 3.0 T: initial experience

After institutional review board approval and informed consent were obtained for this HIPAA-compliant investigation, a three-dimensional electrocardiographically gated variable flip angle (VFA) fast spin-echo magnetic resonance (MR) angiography technique was evaluated as an unenhanced method for imaging hand arteries in 13 subjects (including four patients) at 3.0 T; this included evaluation of vessel visualization with warming and cooling in seven subjects. Examinations were evaluated for image quality and vessel conspicuity. Clear separation of arteries from veins was achieved in all subjects, with excellent vessel conspicuity and depiction of stenoses. Warming improved vessel visualization in healthy volunteers. VFA MR angiography is a high-spatial-resolution technique that enables the assessment of vascular reactivity in response to temperature challenge.