Pancreatic fat content assessed by 1 H magnetic resonance spectroscopy is correlated with insulin resistance, but not with insulin secretion, in Japanese individuals with normal glucose tolerance.

AIMS/INTRODUCTION: Whereas some clinical studies have shown that excessive fat accumulation in the pancreas is associated with impairment of insulin secretion, others have not found such an association. 1 H magnetic resonance spectroscopy allows quantitative fat analysis in various tissues including the pancreas. The pathological relevance of pancreatic fat content (PFC) in Japanese individuals remains unclear, however. MATERIALS AND METHODS: We analyzed PFC in 30 Japanese individuals with normal glucose tolerance by 1 H magnetic resonance spectroscopy, and then investigated the relationships between PFC and indexes of insulin secretion and insulin sensitivity-resistance determined by an oral glucose tolerance test. We also measured hepatic fat content and intramyocellular lipid content by 1 H magnetic resonance spectroscopy, as well as visceral fat area and subcutaneous fat area by magnetic resonance imaging, and we examined the relationships between these fat content measures and oral glucose tolerance test-derived parameters. RESULTS: PFC was correlated with indexes of insulin sensitivity-resistance, but not with those of insulin secretion. Hepatic fat content and visceral fat area were correlated with similar sets of parameters as was PFC, whereas subcutaneous fat area was correlated with parameters of insulin secretion, and intramyocellular lipid content was not correlated with any of the measured parameters. The correlation between PFC and homeostasis model assessment of insulin resistance remained significant after adjustment for age, body mass index and sex. Among fat content measures, PFC was most highly correlated with hepatic fat content and visceral fat area. CONCLUSIONS: PFC was correlated with indexes of insulin resistance, but not with those of insulin secretion in non-obese Japanese individuals with normal glucose tolerance.

[Analysis of accidents for magnetically induced displacement of the large ferromagnetic material in magnetic resonance systems].

To improve magnetic resonance (MR) safety, we surveyed the accidents caused by large ferromagnetic materials brought into MR systems accidentally. We sent a questionnaire to 700 Japanese medical institutions and received 405 valid responses (58%). A total of 97 accidents in 77 institutions were observed and we analyzed them regarding incidental rate, the detail situation and environmental factors. The mean accident rate of each institute was 0.7/100,000 examinations, which was widely distributed (0-25.6/100,000) depending on the institute. In this survey, relatively small institutes with less than 500 beds tend to have these accidents more frequently (p<0.01). The institutes in which daily MR examination counts are more than 10 patients have fewer accidents than those with less than 10 daily examinations. The institutes with 6-10 MR examinations daily have significantly more accidents than that with more than 10 daily MR examinations (p<0.01). The main mental factors of the accidents were considered to be "prejudice" and "carelessness" but some advocate "ignorance." Though we could not find significant reduction in the institutes that have lectures and training for MR safety, we should continue lectures and training for MR safety to reduce accidents due to "ignorance."

Hepatic CT perfusion measurements: a feasibility study for radiation dose reduction using new image reconstruction method.

OBJECTIVES: To assess the effects of image reconstruction method on hepatic CT perfusion (CTP) values using two CT protocols with different radiation doses. MATERIALS AND METHODS: Sixty patients underwent hepatic CTP and were randomly divided into two groups. Tube currents of 210 or 250 mA were used for the standard dose group and 120 or 140 mA for the low dose group. The higher currents were selected for large patients. Demographic features of the groups were compared. CT images were reconstructed by using filtered back projection (FBP), image filter (quantum de-noising, QDS), and adaptive iterative dose reduction (AIDR). Hepatic arterial and portal perfusion (HAP and HPP, ml/min/100ml) and arterial perfusion fraction (APF, %) were calculated using the dual-input maximum slope method. ROIs were placed on each hepatic segment. Perfusion and Hounsfield unit (HU) values, and image noises (standard deviations of HU value, SD) were measured and compared between the groups and among the methods. RESULTS: There were no significant differences in the demographic features of the groups, nor were there any significant differences in mean perfusion and HU values for either the groups or the image reconstruction methods. Mean SDs of each of the image reconstruction methods were significantly lower (p<0.0001) for the standard dose group than the low dose group, while mean SDs for AIDR were significantly lower than those for FBP for both groups (p=0.0006 and 0.013). Radiation dose reductions were approximately 45%. CONCLUSIONS: Image reconstruction method did not affect hepatic perfusion values calculated by dual-input maximum slope method with or without radiation dose reductions. AIDR significantly reduced images noises.

[An investigative report concerning safety and management in the magnetic resonance environment: there are more accidents than expected].

Using a questionnaire, we surveyed 2,500 facilities in Japan to clarify medical accidents concerning the magnetic resonance device and its environment. Data derived from 1,319 valid responses (52.8%), allowed us to analyze the situation of (or the reason for) the occurrence of the accidents and their environmental factors. Five hundred and nine facilities (39% of all facilities) had the experience of magnetically induced displacement of the large ferromagnetic material. Intravenous (I.V.) drip stands were involved the largest number of them: 31% (228 cases). Oxygen bottles had the second largest number of incidents: 20%. There were also many incidents involving various materials brought in by non-medical staff (e.g. stepladder for construction). About 20% of the accidents occurred outside of working hours. Patients in 12% of the facilities (154 facilities) experienced burns. In 39 of the cases, burns were received to the inside of the thighs. In 38 of the cases, patients received burns from an electrical cable touching the skin. There were also frequent incidents of burning regarding the boa. We received reports of burns and pain from the halo vest even though it's required to be worn for MR safety. Regarding incidents of contraindications, 280 patients with pacemakers were brought into the magnetic resonance (MR) inspection room. Twelve percent of the facilities experienced natural quench. Lack of training for the staff who introduce and operate high magnetic field devices are considered involving frequently occurring accidents of attractions and burns at hospitals with over 500 beds caused by carrying in materials.

Apparent diffusion coefficient and fractional anisotropy in the vertebral bone marrow.

PURPOSE: To assess the state of cancellous tissue we analyzed the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in vertebral bone marrow. MATERIALS AND METHODS: With 1.5 T magnetic resonance imaging (MRI), single-shot diffusion echo planar imaging was used with b factors of 0 and 1000 s/mm(2), diffusion-sensitizing gradient in six directions, sensitivity encoding technique, effective TE of 74 msec, and TR of 1800 msec. ADC and FA were determined in the lumbar vertebral body of 11 normal subjects (age 31 632-635 years), and then compared with the bone mineral density (BMD) obtained with dual-energy x-ray absorptiometry (DXA). Moreover, fat fraction (FF) of the bone marrow was measured with spectral presaturation with inversion recovery (SPIR) in the same subject. RESULTS: A strong negative correlation was found between ADC and BMD for low or moderate FF in vertebral bone marrow. Moreover, a significant positive correlation was noted between ADC and FF in this region. There was a positive correlation between FA and BMD, and no correlation between FA and FF in the vertebral bone marrow. CONCLUSION: Diffusion analyses with ADC and FA make it possible to obtain more detailed information on the structure of cancellous tissue and bone metabolism.

Functional MRI of regional brain responses to 'pleasant' and 'unpleasant' odors.

CONCLUSIONS: Our findings demonstrate that functional MRI (fMRI) combined with a questionnaire is a useful method for studying the neuroanatomy of olfaction. Further studies with various odorants and questionnaires would provide an even better understanding of the mechanism of olfactory perception. OBJECTIVES: To better understand the mechanism of odorant perception in the central nervous system. SUBJECTS AND METHODS: fMRI was used to identify the activated regions during stimulation by two odorants, beta-phenyl ethyl alcohol and gamma-undecalactone. Participants were asked to describe the quality of the odor and to rate odor intensity and odor hedonic valence. Activation at each region was statistically analyzed according to the answers. RESULTS: The bilateral middle orbitofrontal cortex (OFC), left lateral OFC, right insula, and bilateral anterior/middle cingulate gyri were most frequently activated by odor stimulation. Left middle OFC was significantly more often activated in the participants who could not identify the odor correctly (p = 0.016). The left middle OFC and right lateral OFC were significantly more often activated in the participants who perceived the odor stimulation as unpleasant (p = 0.03), while the right anterior cingulate gyrus was more often activated in those who perceived the odor as pleasant (p = 0.03).

Utility of phase contrast MR imaging for assessment of pulmonary flow and pressure estimation in patients with pulmonary hypertension: comparison with right heart catheterization and echocardiography.

PURPOSE: To compare the utility of phase contrast MR imaging (PC-MRI) for assessment of pulmonary flow and pressure estimation with that of right heart catheterization and echocardiography (cardiac US) in patients with pulmonary arterial hypertension (PAH). MATERIALS AND METHODS: Twenty consecutive patients with suspected PAH underwent PC-MRI, cardiac US, and right heart catheterization. In each patient, PC-MRI was acquired by cine 2D-PC method on a 1.5 Tesla scanner, and stroke volume (SV) and pulmonary arterial systolic pressure (PASP) were assessed by using the modified Bernoulli's equation. To evaluate the agreements of SV and PASP among the three methods, correlations and limits of agreement among the three methods were statistically assessed by using the Bland-Altman's analyses. RESULTS: The correlations and limits of agreement for SV and PASP between PC-MRI and catheterization (r = 0.96, r(2) = 0.94, 1.1 +/- 6.9 mL and r = 0.94, r(2) = 0.88, -3.2 +/- 14.5 mmHg, respectively) were better than between cardiac US and catheterization (r = 0.01, r(2) < 0.01, 8.9 +/- 42.1 mL and r = 0.86, r(2) = 0.72, -5.9 +/- 27.7 mmHg, respectively). CONCLUSION: PC-MRI is more compatible with right heart catheterization than cardiac US in pulmonary flow and pressure estimation.

[Examination of accuracy and factors influencing optical coherence tomography(OCT)measurements].

INTRODUCTION: Optical coherence tomography (OCT) is a new imaging modality with increasing clinical application. In the present study, we examined the accuracy and factors influencing the OCT measurements (luminal diameter, area, and stent strut thickness). METHODS: We evaluated several luminal sizes of phantom model by OCT with several situations (frame-rate: 8.2 or 15.6 F/s; pullback-speed: 1.0 or 2.0 mm/s; position of Image Wire: in-center; off-center) and compared them with the actual value and the intravascular ultrasound measurements. We also evaluated the accuracy of the stent strut thickness (5 bare metal stents and 2 drug eluting stents) in stents that were implanted to phantom models. RESULTS: The accuracy of OCT measurements was affected by frame-rate and the position of OCT Image Wire. The distortion and the change in brightness of the OCT image were detected when the Image Wire was positioned off-center, especially at low frame-rate. In this condition, OCT measured the luminal diameter and area larger than the actual size. As for the strut thickness, when we unified the measurement points of the stent strut surface, the precision of the OCT measurements was satisfactory. CONCLUSION: We revealed that the precision of the OCT measurements was satisfactory. However, we should note that the OCT measurements were affected by frame-rate and position of the Image Wire.

Observation of gastro-esophageal reflux by MRI: a feasibility study.

PURPOSE: To evaluate the feasibility of detecting and measuring gastro-esophageal reflux (GER) with esophageal MR fluoroscopy in patients suffering from heartburn. MATERIALS AND METHODS: Twenty patients with heartburn underwent esophageal MR fluoroscopy. The T1-FFE sequence was applied for MR imaging. We examined the frequency and the level of GER on MR images. Based on the MRI observations, patients were classified into four MRI grades (grade 1-4). Endoscopic findings were categorized into five grades (grade 0 to D). The overall MRI grade, Carlsson's questionnaire score, and endoscopic findings were compared. RESULTS: GER was observed with MR fluoroscopy in 19 of 20 patients. GER was observed only several times in three patients, and much more frequently in the remaining 16 patients. Elevated levels of GER reached the lower, middle-to-upper esophagus, and the hypopharynx. The observed MRI grades were grade 1 = 1 patient, grade 2 = 3 patients, grade 3 = 2 patients, and grade 4 = 13 patients. There was no statistical correlation between the questionnaire score and the MRI grade. Also, there was no correlation between the grade of endoscopic findings and MRI grade. Six patients demonstrated continuous reflux on MRI did not show mucosal injury at endoscopy. CONCLUSION: Esophageal MR fluoroscopy may be a useful diagnostic tool for GERD for its ability to show GER, even in patients with no mucosal injury, and for suggesting the cause of the reflux.

Reduced fractional anisotropy in early-stage cerebellar variant of multiple system atrophy.

BACKGROUND: In patients with the cerebellar variant of multiple system atrophy (MSA-C), reduced fractional anisotropy (FA) has been reported in several brain areas. However, since previous studies have employed predetermined regions of interest (ROI), the brain areas showing the earliest alterations in FA are unknown. The sensitivity of detecting early-stage MSA-C and the time course of the FA reduction are also unknown. The purpose was to address these issues to determine the diagnostic value of FA for early diagnosis. METHODS: Twenty-one patients with MSA-C were investigated. Voxel-based FA analysis and morphometry were used to detect the differences between early-stage MSA-C and normal controls. An ROI-based FA analysis was also used to clarify the temporal profile. RESULTS: From the early-stage, MSA-C patients exhibited reduced FA and white matter atrophy in the middle cerebellar peduncle, the inferior cerebellar peduncle, and the ventral pons. The FA of these areas decreased rapidly during the first few years after onset, after which a rather gradual reduction occurred. The receiver operating characteristics analysis revealed a high sensitivity and specificity for discriminating early MSA-C from normal controls. CONCLUSIONS: FA measurement could potentially be used to make an early diagnosis and monitor progression in MSA-C patients.

Abdominal apparent diffusion coefficient measurements: effect of diffusion-weighted image quality and usefulness of anisotropic images.

This study aimed to assess the effect of diffusion-weighted image (DWI) quality on abdominal apparent diffusion coefficient (ADC) measurements and the usefulness of anisotropic images. Twenty-six patients (10 men and 16 women; mean, 58.1 years) who underwent DW imaging and were diagnosed not to have any abdominal diseases were analyzed. Single-shot spin-echo echo-planar DW imaging was performed, and one isotropic and three orthogonal anisotropic images were created. ADCs were calculated for liver (four segments), spleen, pancreas (head, body, tail) and renal parenchyma. Image quality for each organ part was scored visually. We estimated the correlation between ADC and image quality and evaluated the feasibility of using anisotropic images. ADCs and image quality were affected by motion probing gradient directions in the liver and pancreas. A significant inverse correlation was found between ADC and image quality. The r values for isotropic images were -.46, -.48, -.70 and -.28 for the liver, spleen, pancreas and renal parenchyma, respectively. Anisotropic images had the best quality and lowest ADC in at least one organ part in 17 patients. DWIs with the best quality among isotropic and anisotropic images should be used in the liver and pancreas.

Influences of prolonged apnea and oxygen inhalation on pulmonary hemodynamics during breath holding: quantitative assessment by velocity-encoded MR imaging with SENSE technique.

PURPOSE: The purpose of our study was to assess the influence of prolonged apnea and administration of oxygen on pulmonary hemodynamics during breath holding (BH) by using velocity-encoded MR imaging combined with the SENSE technique (velocity MRI). MATERIALS AND METHODS: Ten healthy male volunteers underwent velocity MRI during BH with and without O(2) inhalation. All velocity MRI data sets were obtained continuously with the 2D cine phase-contrast method during a single BH period. The data were then divided into three BH time phases as follows: first, second and third. To evaluate the influence of prolonged apnea on hemodynamics, stroke volume (SV) and maximal change in flow rate during ejection (MCFR) of second and third phases were statistically compared with those of first phase by using the ANOVA followed by Turkey's HSD multiple comparison test. To assess the influence of O(2) on hemodynamics, SV and MCFR with or without O(2) were compared by the paired t-test. To assess the measuring agreement of hemodynamic indices during prolonged breath holding, Bland-Altman's analysis was performed. RESULTS: Prolonged apnea had no significant influence on SV and MCFR regardless of administration of O(2) (p>0.05). Mean MCFR for all phases was significantly lower with administration of O(2) than without (p<0.05). The limits of agreement for MCFR with O(2) were smaller than without. CONCLUSION: O(2) inhalation modulated maximal change in flow rate during ejection, and did not influence stroke volume during breath holding. Influence of O(2) inhalation should be considered for MR measurements of pulmonary hemodynamics during breath holding.

Effects of pioglitazone and metformin on intracellular lipid content in liver and skeletal muscle of individuals with type 2 diabetes mellitus.

Both ectopic fat accumulation and changes of the amount of several adipocyte secreting proteins (adipokines) are thought to contribute to the development of insulin resistance associated with obesity and type 2 diabetes mellitus. We have now investigated the effects of 2 insulin-sensitizing drugs, pioglitazone and metformin, on body fat composition and serum adipokine concentrations in individuals with type 2 diabetes mellitus. A total of 41 diabetic patients were treated with pioglitazone (n =21) or metformin (n =20) for 6 months. Intramyocellular lipid content (IMCL) and hepatic lipid content as well as the areas of subcutaneous and visceral fat deposits in the abdomen were determined by nuclear magnetic resonance spectroscopy before and after drug treatment. The serum concentrations of adiponectin and retinol binding protein 4 were also determined by enzyme-linked immunosorbent assays. Pioglitazone treatment reduced both hepatic lipid content (12.0 +/- 6.1 vs 8.4 +/- 3.7 arbitrary units [AU], P < .01) and IMCL (8.4 +/- 3.6 vs 6.3 +/- 2.4 AU/creatine, P < .01), whereas metformin reduced only IMCL (7.0 +/- 3.6 vs 5.8 +/- 2.0 AU/creatine, P < .05). Although the areas of visceral and subcutaneous fat were not significantly affected by treatment with either drug, pioglitazone induced a significant reduction in the ratio of visceral to subcutaneous fat area (0.92 +/- 0.41 vs 0.85 +/- 0.41, P < .05). Pioglitazone treatment also resulted in a marked increase in serum adiponectin concentration (5.6 +/- 4.1 vs 16.2 +/- 9.9 microg/mL, P < .0001) and a small but significant decrease in serum retinol binding protein 4 concentration (73.4 +/- 25.1 vs 65.1 +/- 23.7 microg/mL, P < .05). These results suggest that pioglitazone may improve insulin sensitivity both by affecting serum adipokine concentrations and by reducing the intracellular triglyceride content of liver and skeletal muscle in individuals with type 2 diabetes mellitus.

Influence of inversion pulse type in assessing lung-oxygen-enhancement by centrically-reordered non-slice-selective inversion-recovery half-Fourier single-shot turbo spin-echo (HASTE) sequence.

PURPOSE: To demonstrate the influence of inversion pulse type and inversion time for assessment of oxygen-enhancement on centrically-reordered non-slice-selective inversion-recovery (IR) half-Fourier single-shot turbo spin-echo (HASTE) sequence. MATERIAL AND METHODS: Phantoms with and without 100% oxygen and three healthy volunteers were studied with two-dimensional (2D) centrically-reordered non-slice selective IR-HASTE sequence with either composite or block inversion-recovery pulse at increasing inversion times from 200 to 1800 msec. Signal-to-noise ratios (SNRs) of phantom, real signal differences, and relative enhancement ratios of lung parenchyma between oxygen-enhanced and non-oxygen-enhanced MR images on composite and block pulse type were statistically compared at each TI. RESULTS: SNRs at TIs of 200 and 400 msec using the composite inversion pulse type were significantly lower than those with the block inversion pulse in the in vivo study (P < 0.05), although no significant differences were observed in the phantom study and in the in vivo study at inversion times greater than or equal to 600 msec. Real signal intensity (SI) differences at 400 and 600 msec of the composite inversion pulse type were significantly higher than those with the block inversion pulse type (P < 0.05). Relative enhancement ratio at 800 msec with the composite inversion pulse were significantly lower than that with the block inversion pulse (P < 0.05). CONCLUSION: IR pulse type and inversion time have influence on assessment of oxygen-enhancement by centrically-reordered non-slice-selective IR-HASTE sequence.

ADC measurement of abdominal organs and lesions using parallel imaging technique.

OBJECTIVE: The purpose of our study was to assess the reliability and usefulness of parallel imaging for apparent diffusion coefficient (ADC) measurement of abdominal organs and lesions. MATERIALS AND METHODS: Single-shot spin-echo echo-planar diffusion-weighted MRI (TE = 66, b = 0, 600 s/mm2) was performed in phantom and clinical studies. The b value was set to minimize the effects of perfusion in tissue and to maintain signal-to-noise ratio. Bottle phantoms were scanned with and without parallel imaging and with various parallel imaging factors and at various positions to evaluate the effects of parallel imaging on ADCs. In 200 consecutive clinical patients (122 men and 78 women: mean age, 61.9 years), ADCs were calculated for liver (four segments), spleen, pancreas (head, body, tail), gallbladder, renal parenchyma, and back muscle, and then compared to evaluate the reliability of clinical ADC measurements with parallel imaging. ADCs were also calculated for diffuse diseases and focal lesions (94 malignant and 93 benign) of abdominal organs to evaluate the clinical usefulness of ADC. RESULTS: Location-dependent changes in water ADCs were minimal with parallel imaging factors first of 3, then of 4, and were small except for measurements at the image periphery. Acetone ADCs were saturated at 4.00 x 10(-3) mm2/s. Degraded image quality prevented ADC measurement of the left hepatic lobe and pancreas in 7-18 patients. There was no significant difference among ADCs of four liver segments (1.50 +/- 0.24 [SD] x 10(-3) mm2/s - 1.56 +/- 0.31 x 10(-3) mm2/s) and between ADCs of the right and left kidneys (2.65 +/- 0.30 x 10(-3) mm2/s, 2.59 +/- 0.33 x 10(-3) mm2/s). ADC of the pancreas tail (1.65 +/- 0.37 x 10(-3) mm2/s) was significantly lower than those of the head (1.81 +/- 0.40 x 10(-3) mm2/s) and body (1.81 +/- 0.41 x 10(-3) mm2/s) (p < 0.005). Renal ADCs were significantly lower in patients with renal failure (right: 2.15 +/- 0.30 x 10(-3) mm2/s; left: 2.11 +/- 0.25 x 10(-3) mm2/s) than in those without disease (right: 2.67 +/- 0.29 x 10(-3) mm2/s; left: 2.60 +/- 0.32 x 10(-3) mm2/s) (p < 0.005). ADC of pancreatic cancer was significantly higher than that of healthy pancreas (p < 0.05). ADC of renal angiomyolipoma was significantly lower than those of renal cell carcinoma and healthy renal parenchyma (p < 0.0005). CONCLUSION: Clinical ADC measurements of abdominal organs and lesions using parallel imaging appear to be reliable and useful, and the effect of parallel imaging on calculated values is considered to be minimal.

High-resolution MRI using a microscopy coil for the diagnosis of recurrent lateral patellar dislocation.

PURPOSE: Magnetic resonance imaging (MRI) has been commonly used for the preoperative evaluation of recurrent lateral patellar dislocation (RLPD). The purpose of this study was to determine the usefulness of high-resolution MRI (HR-MRI) with a microscopy coil for diagnosing RLPD. MATERIALS AND METHODS: The study group consisted of 15 patients with clinically diagnosed RLPD and 10 normal volunteers. All studies were performed on a 1.5-T MR system. First, conventional MRIs of the whole knee joint were obtained using the knee coil. Then HR-MRI scans using a microscopy coil in the medial aspect of the patella were obtained at the level of the superior pole of the patella, targeting the medial patellofemoral ligament (MPFL). The acquired HR-MRIs with RLPD were reviewed concerning the MPFL injury and the patellar injury. RESULTS: The MPFL was distinguished as a separate ligament, and the layer structure of the patellar cartilage was visualized clearly in all volunteers. The MPFL injury was visualized in 12 cases (87%); it included discontinuity, thickening, and loosening. The patellar injury was visualized in 11 cases (73%), which included dissecans of the medial margin and cartilage injuries. CONCLUSION: HR-MRI with a microscopy coil provides precise information of the MPFL and patellar cartilage injury for the diagnosis of RLPD.

[Effects of magnetic resonance imaging on neutrophil functions].

We evaluated the effects of magnetic resonance (MR) imaging on human neutrophil functions. In addition of the counting of leukocyte and neutrophil number, expression levels of adhesion molecules on neutrophil surface such as CD11b and L-selectin, and reactive oxygen species (ROS) production were determined by means of flowcytometry. Complete blood count did not show any difference between before and after MR imaging in five normal healthy volunteers. The levels of cell surface adhesion molecules were not altered in both in vivo MR imaging (n=5) and in vitro MR exposure experiments (n=13). Moreover, the levels of ROS production were also not affected by in vivo MR imaging. On the other hand, neutrophils exposed to MR in vitro exhibited significant increase in ROS production after stimulation with fMLP combined with lipopolysaccharide, although no increase was observed with PMA stimulation. Actually, there have been no reports describing the complication relating to hyper-neutrophil function as far as we could search, but it might be necessary to evaluate the biological effects of MR imaging especially under the pathologic circumstances that induce neutrophil activation.