Contrast-enhanced Magnetic Resonance Imaging Techniques Research Articles

A comprehensive MRI analysis of osteoid osteomas in patients with diverse radiological features across various regions.

Magnetic resonance imaging (MRI), which does not involve ionizing radiation, is the preferred imaging modality for diagnosing osteoid osteoma (OO), an ailment more common in children and young adults. This study aims to perform a literature review and delineate the MRI findings of OO lesions in patients exhibiting varying radiological features across different regions. A retrospective study included 63 patients diagnosed with OO through MRI, assessed independently by two blinded radiologists using both standard and dynamic contrast-enhanced MRI techniques. After excluding 7 patients with prior biopsy, surgery, or RFA, the study included 56 patients with 57 lesions. Of 57 lesions evaluated, 50 were in long, and 7 in flat bones. One patient presented with two separate nidi within the intertrochanteric region. Most of the lesions, 49 (86%), were extra-articular, while 8 (14%) were intra-articular. The nidus was intracortical in 45 (78.9%) patients, intramedullary in 5 (8.8%), subperiosteal in 5 (8.8%), and endosteal in 2 (3.5%). Average nidus diameter was 7.02 ± 2.64 mm (3-12.6 mm). Central nidal calcification was present in 68.4% (n = 39) cases. Contrast enhancement was intense at 90.5%, moderate at 9.5%. Reactive sclerosis around the nidus was severe (50.9%), moderate (22.8%), and mild (26.3%). Bone marrow edema was severe (70.2%), moderate (14.0%), and mild (15.8%). Soft tissue edema was identified in 77.2% of all lesions. To minimize delays in diagnosis and treatment, radiologists should become acquainted with the typical OO MRI findings and the atypical MRI findings that might be mistaken for other conditions.

Multicenter Standardization of Phase-Resolved Functional Lung MRI in Patients With Suspected Chronic Thromboembolic Pulmonary Hypertension.

Detection of pulmonary perfusion defects is the recommended approach for diagnosing chronic thromboembolic pulmonary hypertension (CTEPH). This is currently achieved in a clinical setting using scintigraphy. Phase-resolved functional lung (PREFUL) magnetic resonance imaging (MRI) is an alternative technique for evaluating regional ventilation and perfusion without the use of ionizing radiation or contrast media. To assess the feasibility and image quality of PREFUL-MRI in a multicenter setting in suspected CTEPH. This is a prospective cohort sub-study. Forty-five patients (64 ± 16 years old) with suspected CTEPH from nine study centers. 1.5 T and 3 T/2D spoiled gradient echo/bSSFP/T2 HASTE/3D MR angiography (TWIST). Lung signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were compared between study centers with different MRI machines. The contrast between normally and poorly perfused lung areas was examined on PREFUL images. The perfusion defect percentage calculated using PREFUL-MRI (QDPPREFUL) was compared to QDP from the established dynamic contrast-enhanced MRI technique (QDPDCE). Furthermore, QDPPREFUL was compared between a patient subgroup with confirmed CTEPH or chronic thromboembolic disease (CTED) to other clinical subgroups. t-Test, one-way analysis of variance (ANOVA), Pearson's correlation. Significance level was 5%. Significant differences in lung SNR and CNR were present between study centers. However, PREFUL perfusion images showed a significant contrast between normally and poorly perfused lung areas (mean delta of normalized perfusion -4.2% SD 3.3) with no differences between study sites (ANOVA: P = 0.065). QDPPREFUL was significantly correlated with QDPDCE (r = 0.66), and was significantly higher in 18 patients with confirmed CTEPH or CTED (57.9 ± 12.2%) compared to subgroups with other causes of PH or with excluded PH (in total 27 patients with mean ± SD QDPPREFUL = 33.9 ± 17.2%). PREFUL-MRI could be considered as a non-invasive method for imaging regional lung perfusion in multicenter studies. 3 TECHNICAL EFFICACY: Stage 1.

Increased Blood-Brain Barrier Permeability of the Thalamus Correlated With Symptom Severity and Brain Volume Alterations in Patients With Schizophrenia

BackgroundWhile direct in vivo data from patients is insufficient, cumulative evidence of microvascular dysfunction has shown that the blood-brain barrier (BBB) is disrupted in schizophrenia. In this study, we attempted to test the hypothesis that greater BBB permeability in patients with schizophrenia was associated with clinical characteristics and brain volumetric alterations using dynamic contrast-enhanced magnetic resonance imaging techniques. MethodsStructural magnetic resonance imaging and dynamic contrast-enhanced magnetic resonance imaging data from 29 patients with schizophrenia and 18 age- and sex-matched control subjects were obtained. We calculated the volume transfer constant (Ktrans) value and compared the difference between the 2 groups. The regions with an abnormal Ktrans value were extracted as regions of interest (thalamus), and the correlations with clinical characteristics and gray matter volume were analyzed. ResultsThe results revealed that Ktrans value of the bilateral thalamus was higher in the schizophrenia group as compared to the healthy control group (p < .001). There were significant positive correlations between thalamic mean Ktrans value with disease duration (p < .05) and symptom severity (p < .001). Analysis of the thalamic subregions revealed that BBB disruption was significant in the pulvinar, especially the medial pulvinar nucleus and lateral pulvinar nucleus (p < .001). The correlation between the Ktrans values and the corresponding volumes was negative for the whole brain, the thalamus, and the thalamic subregions. ConclusionsThese results provide the first in vivo evidence of BBB disruption of thalamus in patients with schizophrenia and suggest that BBB dysfunction might contribute to the pathological brain structural alterations in schizophrenia.

Surveillance Strategies for Hepatocellular Carcinoma: Recent Advances and the Shifting Paradigm

Currently, international liver societies recommend screening at-risk individuals for HCC (patients with cirrhosis regardless of etiology, and/or chronic hepatitis B virus, and/or advanced liver fibrosis) with biannual abdominal ultrasound (USG) with or without alpha-fetoprotein (AFP). The global acceptance of USG in surveillance relies on the absence of risks, non-invasiveness, and lower costs. However, the suboptimal performance of USG ± AFP in reaching direct and indirect goals of HCC surveillance highlights the need for alternative surveillance strategies. Several studies targeted contrast-enhanced magnetic resonance imaging techniques, but the main barriers for their entrance to surveillance programs have been concerns about cost-effectivity and long scan times. Overall, the HCC risk stratification appears at hand by several validated multiple score systems, but their optimal performance is obtained only in populations who show highly homogenous clinical, pathological, epidemiologic, etiologic, and therapeutic characteristics, and this limitation poses a major drawback to their sustainable use in clinical practice. We need globally validated and molecular integrated risk stratification tools to shape the future tailored HCC surveillance decision algorithms. A dynamic process for HCC surveillance algorithms awaits us owing to the expected further prospective studies focusing on risk-stratified screening strategy.

MRI in Menière’s Disease

The visualization of the morphologic substrate of Meniere’s disease -the endolymphatic hydrops – can be performed using non-contrast as well as contrast-enhanced magnetic resonance imaging techniques. The non-contrast magnetic resonance imaging technique uses a heavily T2-weighted sequence; however, the reproducibility of this technique remains to be confirmed. The contrast-enhanced techniques most frequently use a 3-dimensional fluid-attenuated inversion recovery sequence or a real 3-dimensional inversion recovery sequence either after intratympanic gadolinium administration either 4 hours after intravenous gadolinium administration. The latter is the most frequently used technique and is able to detect definite Meniere’s disease with a high sensitivity and specificity. It has been proven to be a reliable technique with a high diagnostic accuracy, enabling the visualization of endolymphatic hydrops.

Clinical utility of eco-color-power Doppler ultrasonography and contrast enhanced magnetic resonance imaging for interpretation and quantification of joint synovitis: a review.

With the introduction of new biologics such as anti-TNF-alpha antibodies and other therapies in the treatment of inflammatory arthritis, capable of halting joint destruction and functional disability, there are new pressures on diagnostic and prognostic imaging. Early demonstration of pre-erosive inflammatory features and monitoring of the long-term effects of treatment are becoming increasingly important. Early detection of synovitis offers advantages in terms of allowing early instigation of therapy and may allow the identification of those patients displaying more aggressive disease who might benefit from early intervention with expensive DMARD therapy. Advanced imaging techniques such as ultrasound (US) and magnetic resonance imaging (MRI) have focussed on the demonstration and quantification of synovitis and allow early diagnosis of inflammatory arthropathies such as rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Synovitis represents a potential surrogate measure of disease activity that can be monitored using either MRI or US; the techniques have, generally, focused on monitoring synovial volume or quality as assessed by its vascularity. However to achieve these goals, standardisation and validation of US and MRI are required to ensure accurate diagnosis, reproducibility and reliability. Each modality has different strengths and weaknesses and levels of validation. This article aims to increase the awareness of radiologists and rheumatologists about this field and to encourage them to participate and contribute to the ongoing development of these modalities. Without this collaboration, it is unlikely that these modalities will reach their full potential in the field of rheumatological imaging. This review is in two parts. The first part addresses the role of US and colour or power Doppler sonography (PDUS) in the detection and monitoring of synovitis in inflammatory arthropathies. The second part will look at advanced MR imaging and Dynamic contrast-enhanced MRI techniques and in particular how they are applied to the monitoring of the disease process. (www.actabiomedica.it)

Predicting the prognosis of non-small cell lung cancer patient treated with conservative therapy using contrast-enhanced MR imaging.

The aim of this study was to evaluate the therapeutic effect more accurately and predict the prognosis of treated non-small cell lung cancer by using contrast-enhanced magnetic resonance imaging (CE-MRI). Contrast-enhanced computed tomography (CE-CT) and CE-MRI were examined 90 non-small cell lung cancer patients treated with conservative therapies. Enhancement patterns of CE-MRI were classified into three types: peripheral; mottled; and homogeneous. Reduction ratio of tumor size (RRT) based on the World Health Organization response criteria and a new response rate; reduction ratio of viable tumor size (RRVT) which evaluates not only the reduction of tumor size but also changes in necrosis and/or cavity size, were evaluated. Changes of enhancement pattern were compared and correlated with pathological diagnosis. The RRTs, RRVTs, and interobserver agreements evaluated by all modalities were compared. The RRTs and RRVTs in each subgroup were correlated and compared with prognoses. Change of enhancement pattern depended on therapy had no tendency (p = 0.06). Enhancement pattern had significant correlation with pathological diagnosis (p < 0.0001). Partial response (PR) case of RRVT had significant difference between imaging techniques (p = 0.04). The RRVT of other cases and RRT had no significant difference. Interobserver agreements of RRT and RRVT were almost perfect (n > or = 0.93). Prognosis had better correlation with RRVT than with RRT. Differences of relapse-free survival and survival between patients considered as having no change (NC) by RRT and PR by RRVT (NC-PR) and patients considered as having NC by RRT and RRVT were significant (p = 0.03, p = 0.01). There were no significant differences of relapse-free survival and survival between NC-PR patients and patients considered as having PR by RRT and RRVT. The CE-MRI technique could accurately evaluate the therapeutic effect and predict the prognosis of treated non-small cell lung cancer.

Tumor angiogenesis, vascularization, and contrast-enhanced magnetic resonance imaging.

Angiogenesis, the process by which new blood vessels are generated, occurs during wound healing, in the female reproductive system during ovulation and gestation, and during embryonic development. The process is carefully controlled with positive and negative regulators, because several vital physiological functions require angiogenesis. The consequences of abnormal angiogenesis are either excessive or insufficient blood vessel growth. Ulcers, strokes, and heart attacks can result from the absence of angiogenesis normally required for natural healing, whereas excessive blood vessel proliferation may favor tumor growth and dissemination, blindness, and arthritis. In this review, the process of angiogenesis and the characteristics of the resulting tumor vasculature are outlined. Contrast-enhanced magnetic resonance imaging techniques that currently are available for basic research and clinical applications to study various aspects of tumor angiogenesis and neovascularization are discussed.