Body Magnetic Resonance Research Articles

Effects of 6 months glucagon‐like peptide‐1 receptor agonist treatment on endothelial function in type 2 diabetes mellitus patients

Glucagon-like peptide-1 receptor agonists (GLP-1 RA) are used for treatment in type 2 diabetes mellitus (T2DM). Little is known about their cardiovascular (CV) impact. We sought to determine the effects of chronic treatment on vascular function in T2DM. Brachial artery endothelial-dependent flow-mediated dilation (FMD) and endothelial-independent glyceryl trinitrate (GTN) function and carotid intima-medial thickness (cIMT) were assessed in 11 severely obese T2DMs (4 females, 7 males: 55 ± 8 years, diabetes duration 8.3 ± 4.7 years mean ± s.d.) before and after 6 months GLP-1 RA. Body weight (5.3 ± 1.2 kg; p < 0.05) and magnetic resonance imaging determined total and subcutaneous fat, but not visceral fat, decreased. Glycaemic control improved. There were no significant changes in FMD, GTN and cIMT (-1.1 ± 0.4%, 0.3 ± 3.0% and 0.00 ± 0.04 mm, respectively). Despite significant improvements in body composition and glycaemic control, 6 months GLP-1 RA treatment did not modulate vascular function. Alternative strategies may therefore be needed to reduce the burden of CV risk in severely obese patients with long-standing T2DM.

Total atherosclerotic burden by whole body magnetic resonance angiography predicts major adverse cardiovascular events

ObjectiveThe purpose of the present study was to investigate the relationship between the Total Atherosclerotic Score (TAS), a measurement of the overall atherosclerotic burden of the arterial tree by whole body magnetic resonance angiography (WBMRA), and the risk of major adverse cardiovascular events (MACE), defined as cardiac death, myocardial infarction, stroke and/or coronary revascularization, assuming that TAS predicts MACE. Methods and results305 randomly selected 70 year-old subjects (47% women) underwent WBMRA. Their atherosclerotic burden was evaluated and TAS > 0, that is atherosclerotic changes, were found in 68% of subjects. During follow-up (mean 4.8 years), MACE occurred in 25 subjects (8.2%). Adjusting for multiple risk factors, TAS was associated with MACE (OR 8.86 for any degree of vessel lumen abnormality, 95%CI 1.14–69.11, p = 0.037). In addition, TAS improved discrimination and reclassification when added to the Framingham risk score (FRS), and ROC (Receiver Operator Curve) increased from 0.681 to 0.750 (p = 0.0421). ConclusionIn a population-based sample of 70 year old men and women WBMRA, with TAS, predicted MACE independently of major cardiovascular risk factors.

A comparative study of whole body DWIBS MRI versus bone scan for evaluating skeletal metastases.

Skeletal metastases in oncology patients are identified by Bone scan and/Positron Emission Tomography (PET) scan. But developing countries in the world still lack adequate numbers of these imaging facilities. Since Magnetic Resonance Imaging (MRI) is widely available as compared to bone scan or PET scan; a double blind study was undertaken to see if whole body imaging with MRI can give an idea of skeletal metastases. Diffusion weighted whole body Magnetic Resonance Imaging with background body signal suppression (DWIBS) was performed using 1.5 Tesla (T) MRI on histopathologically proven cases of carcinoma of breast within two months of mastectomy and followed up after a year of surgery. Similarly bone scan was also performed in these patients. DWIBS MRI demonstrated the presence and extent of bone metastases in 10 out of a total 18 patients included in study while bone scan could demonstrate them in only three cases. A highly significant difference between proportions of the skeletal metastases detected by whole body DWIBS-MRI than that by bone scan at one year follow-up. (i.e. p<0.01, z=2.66) was seen. DWIBS MRI scores high in demonstrating skeletal metastases. Further comparative studies are necessary to evaluate if DWIBS can replace bone scan or PET scan.

Improved Glycaemia Correlates with Liver Fat Reduction in Obese, Type 2 Diabetes, Patients Given Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists

Glucagon-like peptide-1 receptor agonists (GLP-1 RA) are effective for obese patients with type 2 diabetes mellitus (T2DM) because they concomitantly target obesity and dysglycaemia. Considering the high prevalence of non-alcoholic fatty liver disease (NAFLD) in patients with T2DM, we determined the impact of 6 months’ GLP-1 RA therapy on intrahepatic lipid (IHL) in obese, T2DM patients with hepatic steatosis, and evaluated the inter-relationship between changes in IHL with those in glycosylated haemoglobin (HbA1c), body weight, and volume of abdominal visceral and subcutaneous adipose tissue (VAT and SAT). We prospectively studied 25 (12 male) patients, age 50±10 years, BMI 38.4±5.6 kg/m2 (mean ± SD) with baseline IHL of 28.2% (16.5 to 43.1%) and HbA1c of 9.6% (7.9 to 10.7%) (median and interquartile range). Patients treated with metformin and sulphonylureas/DPP-IV inhibitors were given 6 months GLP-1 RA (exenatide, n = 19; liraglutide, n = 6). IHL was quantified by liver proton magnetic resonance spectroscopy (1H MRS) and VAT and SAT by whole body magnetic resonance imaging (MRI). Treatment was associated with mean weight loss of 5.0 kg (95% CI 3.5,6.5 kg), mean HbA1c reduction of 1·6% (17 mmol/mol) (0·8,2·4%) and a 42% relative reduction in IHL (−59.3, −16.5%). The relative reduction in IHL correlated with that in HbA1c (ρ = 0.49; p = 0.01) but was not significantly correlated with that in total body weight, VAT or SAT. The greatest IHL reduction occurred in individuals with highest pre-treatment levels. Mechanistic studies are needed to determine potential direct effects of GLP-1 RA on human liver lipid metabolism.

Serum Glycated Albumin Is Inversely Influenced by Fat Mass and Visceral Adipose Tissue in Chinese with Normal Glucose Tolerance

BackgroundRecent studies have revealed that body mass index (BMI) inversely influenced serum glycated albumin (GA), which may cause an underestimation of GA-monitored short-term hyperglycemic control.ObjectiveThis study was to investigate the association between anthropometric variables (BMI and waist circumference (W)) and accurate adiposity variables (percentage of body fat (%fat), fat mass, free fat mass (FFM), subcutaneous fat area (SFA), and visceral fat area (VFA)) with serum GA.DesignA total of 2563 subjects (1037 men, 593 premenopausal women, and 933 postmenopausal women) with normal glucose tolerance underwent bioelectrical impedance body fat content measurement and magnetic resonance imaging. Serum GA and absolute value of GA (aGA) were measured by enzymatic assay.ResultsCompared to the BMI <25.0 kg/m2 group, the BMI ≥25.0 kg/m2 group had significantly higher fasting plasma glucose, glycated hemoglobin A1c, and body fat parameters including W, %fat, fat mass, FFM, SFA, and VFA, but significantly lower aGA, and GA in all the three sex- and menopause-stratified groups (all P<0.05). GA decreased with the increment of fat mass for all three groups (all P for trend <0.001). In the same BMI category, men and postmenopausal women with elevated %fat (men, ≥25%; women, ≥35%) still had significantly lower GA than those with normal %fat (men, <25%; women, <35%) (all P<0.05). Multiple stepwise regression showed that %fat, fat mass, and VFA were independently associated with GA.ConclusionsSerum GA was inversely influenced by fat mass and visceral adipose tissue in Chinese with normal glucose tolerance.

Whole Body Magnetic Resonance and CT/PET in patients affected by multiple myeloma during staging before treatment

The diagnostic imaging plays a pivotal role in the staging of multiple myeloma (MM). Traditional imaging techniques allow a precise disease extension before treatment, but some drawbacks have been demonstrated after treatment. WBMRI and CT/PET represent alterative procedures during staging, but few comparative data are available to date. Aim of our study was to estimate the diagnostic accuracy of WB-MRI and CT/PET in 28 consecutive patients affected by MM before therapy. CT/PET was positive in 22/28 patients, whereas WB-MRI correctly identified 100% of patients. In this setting of patients WB MRI have demonstrated to be superior respect to CT/PET in term of diagnostic accuracy, especially when a diffuse disease is detected with a bone marrow aspiration with more than 40% of plasma cells. WBMRI shows a diagnostic accuracy higher than FDG-CT/PET in staging especially when diffuse. However a whole body coverage is crucial to properly manage MM patients irrespective of which technique is used.

Quality Initiatives: Planning, Setting Up, and Carrying Out Radiology Process Improvement Projects

In the coming decades, those who provide radiologic imaging services will be increasingly challenged by the economic, demographic, and political forces affecting healthcare to improve their efficiency, enhance the value of their services, and achieve greater customer satisfaction. It is essential that radiologists master and consistently apply basic process improvement skills that have allowed professionals in many other fields to thrive in a competitive environment. The authors provide a step-by-step overview of process improvement from the perspective of a radiologic imaging practice by describing their experience in conducting a process improvement project: to increase the daily volume of body magnetic resonance imaging examinations performed at their institution. The first step in any process improvement project is to identify and prioritize opportunities for improvement in the work process. Next, an effective project team must be formed that includes representatives of all participants in the process. An achievable aim must be formulated, appropriate measures selected, and baseline data collected to determine the effects of subsequent efforts to achieve the aim. Each aspect of the process in question is then analyzed by using appropriate tools (eg, flowcharts, fishbone diagrams, Pareto diagrams) to identify opportunities for beneficial change. Plans for change are then established and implemented with regular measurements and review followed by necessary adjustments in course. These so-called PDSA (planning, doing, studying, and acting) cycles are repeated until the aim is achieved or modified and the project closed.

Simplified segmented human models for whole body and localised SAR evaluation of 20 MHz to6 GHz electromagnetic field exposures

The digital human model is a key element in evaluating the electromagnetic field (EMF) exposure. This paper proposes the application of simplified segmented human models for EMF exposure compliance evaluation with the whole body and the localised limits. The method is based on the fact that most of the EMF power absorption is concentrated in several major tissues. Two kinds of human models were simply (the proposed method) and precisely segmented from two sets of whole body magnetic resonance imaging (MRI) scanned images. The whole body average-specific absorption rate (WBA-SAR) and the peak localised SAR averaging over 10 g tissues for the two kinds of models are calculated for various exposure configurations. The results confirmed the efficiency and the validity of the proposed method. The application as evaluating the MRI radiofrequency EMF exposure is also discussed in the paper.

Changes in magnetic resonance imaging before and after autologous stem cell transplantation correlate with response and survival in multiple myeloma

In multiple myeloma, focal lesions, as well as diffuse and variegated infiltration patterns, can be detected by magnetic resonance imaging. In the current study, we compared treatment response in 100 myeloma patients with changes in infiltration patterns in whole body magnetic resonance imaging before and after autologous stem cell transplantation. We found an agreement between serological response and changes in imaging (P<0.001). In detail, a significant agreement of treatment response was observed for diffuse (P=0.004) as well as for focal (P=0.01) infiltration patterns. The number of focal lesions at second magnetic resonance imaging was of prognostic significance for overall survival (P=0.001). We conclude that treatment response in myeloma goes along with a decrease in imaging findings. We suggest that residual disease after high-dose chemotherapy detected by magnetic resonance imaging increases the risk of relapse. Therefore, myeloma patients with such findings after treatment might benefit from further cytoreduction.

IRM corps entier dans le diagnostic de l’ostéomyélite chronique multifocale récidivante

Summary Chronic recurrent mutifocal osteomyelitis (CRMO) is a diagnosis of exclusion primarily in children and adolescents. As part of the essential criteria for the diagnosis of CRMO, multifocal lesions must be identified. We present the case of an 11-year-old boy with CRMO, whose diagnosis was facilitated by the use of whole body magnetic resonance imaging (WBMR), but not isotope bone scanning.

Evaluation of CRMO by Whole Body Magnetic Resonance Imaging

Les pompes à insuline sont en plein essor en diabétologie pédiatrique. L’objectif de cette étude était d’évaluer la qualité de vie (QV) et la satisfaction des enfants et adolescents diabétiques de type 1 sous pompe à insuline. Un auto-questionnaire rétrospectif a été distribué à 41 enfants. Il portait sur la QV générale et la QV spécifique au diabète et était complété par des éléments spécifiques à la pompe et sur la satisfaction. Des paramètres cliniques et biologiques dont l’hémoglobine glyquée (HbA1c) ont été comparés avant et après la mise en place de la pompe. Le score de QV sous pompe était positif, d’autant plus qu’elle était mise en place précocement après le diagnostic de diabète (p = 0,03) et chez l’enfant de moins de 8 ans (p < 0,02). Cet effet positif concernait surtout les spécificités de la pompe : « gestion de l’insuline » et « injections » mais aussi la gestion du diabète, les émotions et comportement, la scolarité, la vie en famille, la vie quotidienne et les activités physiques. En revanche, le score pour l’item « vie en société, entourage » n’était pas significatif. La baisse du nombre de piqûres et la souplesse des repas étaient les points les plus positifs. L’HbA1c s’améliorait dès l’indication de la pompe avant sa mise en route (p = 0,005) et était stable pendant 4 ans (p ≤ 0,05). Les oublis des injections, les remarques sur le diabète et les problèmes techniques semblaient faire exception. La pompe modifiait l’image du corps par un sentiment ambivalent de normalité (libertés engendrées) et de différence (visibilité, rappel de la maladie). Les bénéfices de QV et d’équilibre glycémique sous pompe sont indissociables et ne peuvent s’envisager qu’entourés d’un accompagnement médical et paramédical. Améliorer la QV à court et à long terme en diminuant le risque de complications ultérieures constitue le défi quotidien des familles et des diabétologues.Insulin pumps are booming in pediatric diabetology. The objective of this study was to assess changes for children and adolescents with type 1 diabetes using a pump in terms of quality of life (QOL), satisfaction, and glycosylated hemoglobin. A retrospective self-evaluation questionnaire was distributed to 41 patients. It focused on general QOL, diabetes-specific QOL supplemented by specific questions on the pump, and satisfaction. Clinical and biological parameters (glycated hemoglobin: HbA1c) were compared before and after pump use. The score for QOL with the pump was positive, more so if started early after diagnosis of diabetes (P = 0.03) and with children under the age of 8 years (P < 0.02). These positive results are mainly related to the characteristics of the pump, “insulin management” and “injections,” as well as “diabetes management,” “behavior,” “school,” “family life,” “daily life,” and “physical activities.” On the other hand, the improvement was not significant for the item “life in society, friends and family.” A decrease in the number of injections and the flexibility of meals were the most positive points. HbA1c improved as soon as the pump was indicated before its use was begun (P = 0.005) and remained constant for 4 years (P ≤ 0.05). Forgotten injections, comments on diabetes, and technical problems appeared to be exceptional. The pump changed the patient's body image because of ambivalent feelings between being normal (greater freedom) and different (visibility and a reminder of the disease). The benefits in terms of QOL and glycemic control with the pump cannot be dissociated and can only be considered accompanied by paramedical and medical assistance. Improving QOL over the short and long term by reducing the risk of further complications is the daily challenge of families and diabetologists.

Bedeutung der Ganzkörper-MRT beim Staging des kolorektalen Karzinoms

Staging and follow-up of colorectal cancer are usually performed with multimodal imaging strategies. These can be time-intensive and potentially lead to examiner-dependent bias. Alternatively, whole body magnetic resonance imaging (WB-MRI) provides oncologic imaging with a systemic approach. Ultrasound, multislice computed tomography (MSCT), dedicated MRI and positron emission tomography/CT (PET/CT). High-resolution WB-MRI with focused examination of various organs, such as the pelvis and abdomen, lungs, brain and skeletal system, using different sequence and contrast techniques. Detection of colorectal tumor recurrence with WB-MRI provides 83% accuracy (lymph node metastases 80%, organ metastases 86%). Potential cost reduction through decreased examination time and personnel costs. Whole body MRI is a radiation-free alternative to standard sequential algorithms of staging and follow-up of colorectal cancer.

Whole body MRI in the diagnosis of chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is a diagnosis of exclusion primarily in children and adolescents. As part of the essential criteria for the diagnosis of CRMO, multifocal lesions must be identified. We present the case of an 11-year-old boy with CRMO, whose diagnosis was facilitated by the use of whole body magnetic resonance imaging (WBMR), but not isotope bone scanning.

Multiples Myelom: Aktuelle Empfehlungen für die Bildgebung

Imaging in monoclonal plasma cell disease serves to detect end organ damage, i.e., osteoporosis or bone destruction. Diffuse or circumscribed bone marrow infiltration without damage to mineralized bone is so far not regarded as end organ damage. Skeletal plain x-ray film survey to detect bone destruction, osteoporosis or fractures. Whole body low-dose computed tomography (CT) and whole body magnetic resonance imaging (MRI) allow a more sensitive assessment of both mineralized bone and bone marrow, with greater patient comfort and in the case of MRI without ionizing radiation. According to the literature, cross-sectional imaging is clearly superior to skeletal surveys and MRI is more sensitive than CT. Every locally destructive lesion will be detectable with MRI but for assessing the damage to mineralized bone CT is indispensible. The sensitivities of positron emission tomography (PET)/CT and MRI are comparable. If available whole body MRI and whole body low dose CT should replace conventional skeletal surveys. This has already been implemented in several centers in Germany. For the initial diagnosis of monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma or symptomatic multiple myeloma, a whole-body MRI and a whole body low-dose CT should be performed. For MGUS and asymptomatic myeloma, whole body MRI only should be performed for follow-up until detection of first bone destruction. Patients with symptomatic multiple myeloma and known bone destruction will usually have whole body low-dose CT, supplemented by MRI studies where clinically required.

Intrahepatic insulin exposure, intrahepatocellular lipid and regional body fat in nonalcoholic fatty liver disease.

Insulin is pivotal in regulating hepatic lipid synthesis, metabolism, and export. We tested the hypothesis that intrahepatic insulin exposure is an important determinant of intrahepatocellular lipid (IHCL), taking into account regional adiposity and both glucoregulatory and antilipolytic insulin sensitivity. We compared 21 European males with known nonalcoholic fatty liver disease (NAFLD) with 19 healthy male controls. Insulin sensitivity, secretion, and percentage hepatic extraction were derived from iv glucose tolerance test (IVGTT) glucose, insulin, and C-peptide concentrations. Intrahepatic insulin exposure was calculated as percentage hepatic insulin extraction multiplied by basal or IVGTT insulin secretion. IHCL was quantified by proton magnetic resonance spectroscopy. Total and regional adipose tissue was measured using whole body magnetic resonance imaging. Percentage hepatic extraction of newly secreted insulin differed between cases with NAFLD and controls at borderline significance (median, 76 vs. 83%; P = 0.07). Cases had higher intrahepatic insulin exposure than controls, both in the basal (34 vs. 18 pmol; P = 0.0002) and glucose-stimulated states (58 vs. 24 pmol; P = 0.01). IHCL was significantly related to both basal (r(s) = 0.62; P < 0.0001) and IVGTT intrahepatic insulin exposure (r(s) = 0.47; P = 0.002). As predictors of IHCL, both basal and IVGTT intrahepatic insulin exposure were dependent on the waist-to-hip ratio and homeostasis model assessment insulin resistance, but not on magnetic resonance imaging fat measures or IVGTT insulin sensitivity. Men with NAFLD have higher intrahepatic insulin exposure than controls. This correlates with IHCL, but the principal determinants of IHCL were fat distribution and hepatic rather than peripheral insulin resistance.

The relevance of serum carcinoembryonic antigen as an indicator of brain metastasis detection in advanced non-small cell lung cancer

Although many biomarkers have emerged in non-small cell lung cancer (NSCLC), the predictive value of site-specific spread is not fully defined. We designed this study to determine if there is an association between serum biomarkers and brain metastasis in advanced NSCLC. We evaluated 227 eligible advanced NSCLC patients between May 2005 and March 2010. Patients who had been newly diagnosed with stage IV NSCLC but had not received treatment previously, and had available information on at least one of the following pretreatment serum biomarkers were enrolled: carcinoembryonic antigen (CEA), cytokeratin 19 fragments (CYFRA 21-1), cancer antigen 125 (CA 125), cancer antigen 19-9, and squamous cancer cell antigen. Whole body imaging studies and magnetic resonance imaging of the brain were reviewed, and the total number of metastatic regions was scored. Brain metastasis was detected in 66 (29.1%) patients. Although serum CEA, CYFRA 21-1, and CA 125 levels were significantly different between low total metastatic score group (score 1-3) and high total metastatic score group (score 4-7), only CEA level was significantly different between patients with brain metastasis and those without brain metastasis (p < 0.0001). The area under the receiver operating curve of serum CEA for the prediction of brain metastasis was 0.724 (p = 0.0001). The present study demonstrated that the pretreatment serum CEA level was significantly correlated with brain metastasis in advanced NSCLC. These findings suggested the possible role of CEA in the pathogenesis of brain invasion. More vigilant surveillance would be warranted in the high-risk group of patients with high serum CEA level and multiple synchronous metastasis.

Diagnostic accuracy of post-mortem cardiovascular magnetic resonance imaging in fetuses, newborns, and children

Background Whole body magnetic resonance (MR) imaging is increasingly used as an alternative for conventional autopsy; however, a recent systematic review suggested that post-mortem MR imaging had a sensitivity of 12% (95% CI-0.4 to 31) for detecting major cardiac pathology (Thayyil et al. Eur J Radiol 2010; 75(1):e142-8). We wanted to compare the accuracy of high-resolution 3D post-mortem cardiovascular MR (CMR) imaging with conventional cardiac autopsy in fetuses, newborns and children.

Prognostic Significance of the Number of Focal Lesions in Whole Body Magnetic Resonance Imaging Before and After Autologous Stem Cell Transplantation

Abstract 1812Magnetic resonance imaging (MRI) has been demonstrated to be the most sensitive imaging technique to detect both diffuse and focal infiltration of multiple myeloma cells in bone marrow. Whole body magnetic resonance imaging (WB-MRI) can be applied using affordable extensions to standard MRI scanners. Recent studies have shown that the presence and number of focal lesions (FL) in MRI are of prognostic significance in symptomatic as well as smoldering multiple myeloma. The aim of the present study was to investigate the significance of persisting FL after autologous stem cell transplantation. To answer this question WB-MRI of 100 patients eligible for high dose chemotherapy with symptomatic myeloma were retrospectively evaluated before the start of systemic treatment and after single or tandem autologous stem cell transplantation. Number of FL was assessed by two investigators in consensus for each time point separately. The analysis was approved by the institutional ethics committee. Patients were classified into different groups according to the number of FL in WB-MRI. At first MRI, 24 patients presented with 0, 36 with 1–10, 13 with 11–20 and 27 with more than 20 FL. At time of second MRI 25 patients had no, 51 patients 1–10, 13 patients 11–20 and 11 patients more than 20 FL. Overall survival was defined as time from second MRI until death of any cause. MRI-response according to the change of the number of FL was defined as focal complete remission (fCR) indicating total disappearance of FL, focal partial remission (fPR) being defined as reduction of the number of FL of 50% or more, focal stable disease (fSD) as unchanged number of FL and focal progressive disease (fPD) as any increase in number of focal lesions after therapy. At second MRI an fCR was found in 25; an fPR in 22; an fSD in 26 and an fPD in 27 patients. For evaluation of prognostic significance of the number of FL for overall survival a log rank test resulted in a p-value of 0.17 for the first and 0.02 for the second WB-MRI. Kaplan-Meier plots for overall survival according to the number of FL at first and second MRI are shown in Figure 1 and 2 respectively. Number of FL was not of prognostic significance for progression free survival (p = 0.6 and p = 0.8 for first and second MRI respectively). Serological and MRI-defined response concerning FL were significantly associated (p = 0.003; Kendall’s Tau 0.26) with a trend to an underestimation of response in FL compared to serological response. The fact that the number of FL after high dose chemotherapy but not at first diagnosis of symptomatic myeloma had a significant impact on survival in our study confirms the importance of the measurement of residual disease after systemic treatment as it has been demonstrated for methods as flow cytometry and others. Thereby WB-MRI allows the evaluation of nearly the whole bone marrow compartment non-invasively and without the need of irradiation exposure. A limitation of MRI is the fact that it is not capable of differentiating between FL containing vital tumor cells and those representing osteolyses without active myeloma. New functional MRI sequences like dynamic contrast-enhanced MRI and diffusion weighted imaging may overcome this disadvantage. Furthermore, positron emission tomography has been demonstrated to be another possibility for detection of residual disease activity after therapy. Further studies will show which imaging technique is most useful in myeloma or if different clinical and scientific questions necessitate different methods. [Display omitted] [Display omitted] Disclosures:Goldschmidt:Janssen-Cilag: Consultancy; Celgene: Consultancy; Millennium Pharmaceuticals, Inc.: Consultancy.

Comparison of a 28‐channel receive array coil and quadrature volume coil for morphologic imaging and T2 mapping of knee cartilage at 7T

To compare a new birdcage-transmit, 28-channel receive array (28-Ch) coil and a quadrature volume coil for 7T morphologic MRI and T2 mapping of knee cartilage. The right knees of 10 healthy subjects were imaged on a 7T whole body magnetic resonance (MR) scanner using both coils. 3D fast low-angle shot (3D-FLASH) and multiecho spin-echo (MESE) sequences were implemented. Cartilage signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), thickness, and T2 values were assessed. SNR/CNR was 17%-400% greater for the 28-Ch compared to the quadrature coil (P ≤ 0.005). Bland-Altman plots show mean differences between measurements of tibial/femoral cartilage thickness and T2 values obtained with each coil to be small (-0.002 ± 0.009 cm / 0.003 ± 0.011 cm) and large (-6.8 ± 6.7 msec/-8.2 ± 9.7 msec), respectively. For the 28-Ch coil, when parallel imaging with acceleration factors (AF) 2, 3, and 4 was performed SNR retained was: 62%-69%, 51%-55%, and 39%-45%. A 28-Ch knee coil provides increased SNR/CNR for 7T cartilage morphologic imaging and T2 mapping. Coils should be switched with caution during clinical studies because T2 values may differ. The greater SNR of the 28-Ch coil could be used to perform parallel imaging with AF2 and obtain similar SNR as the quadrature coil.

Diffusion‐weighted whole‐body MRI with background body signal suppression: Technical improvements at 3.0 T

To improve image quality of diffusion-weighted body magnetic resonance imaging (MRI) with background body signal suppression (DWIBS) at 3.0 T. In 30 patients and eight volunteers, a diffusion-weighted spin-echo echo-planar imaging sequence with short TI inversion recovery (STIR) fat suppression was applied and repeated using slice-selective gradient reversal (SSGR) and/or dual-source parallel radiofrequency (RF) transmission (TX). The quality of diffusion-weighted images and gray scale inverted maximum intensity projections (MIP) were visually assessed by intraindividual comparison with respect to the level of fat suppression and signal homogeneity. Moreover, the contrast between lesions/lymph nodes and background (C(lb)) was analyzed in the MIP reconstructions. By combining STIR with SSGR, fat suppression was significantly improved (P < 0.001) and C(lb) was increased two times. The use of TX allowed the reduction of acquisition time and improved image quality with regard to signal homogeneity (P < 0.001) and fat suppression (P = 0.005). DWIBS at 3.0 T can be improved by using SSGR and TX.