Original Research
Gastrointestinal Imaging
August 2010

MR Elastography: Spleen Stiffness Measurements in Healthy Volunteers—Preliminary Experience

Abstract

OBJECTIVE. The purpose of this article is to establish the range of normal splenic stiffness in healthy volunteers using MR elastography (MRE) and to investigate any correlation with physiologic parameters and driver position.
SUBJECTS AND METHODS. Sixteen volunteers (mean [± SD] age, 37 ± 9 years) with no history of gastrointestinal, hepatobiliary, or cardiovascular disease were recruited. The MRI protocol included T2-weighted axial and gradient-echo MRE sequences using steady-state 60-Hz excitation. Two MRE acquisitions were performed, one with the driver placed on the right side of the abdomen and the other with the driver placed on the left side. Volunteers' body mass index (BMI), arterial mean blood pressure, age, spleen volume, and liver stiffness were also determined. Two radiologists independently measured the spleen stiffness on the MRE inversion images. The correlations between spleen stiffness and BMI, arterial mean blood pressure, age, spleen volume, and liver stiffness were quantified.
RESULTS. Sixteen volunteers underwent MRE. With the driver placed on the right side of the abdomen, the mean splenic stiffness was 3,565 ± 586 Pa (range, 2,353–4,442 Pa); with the driver on the left side of the abdomen, the mean splenic stiffness was significantly (p < 0.004) different (4,255 ± 625 Pa; range, 3,194–5,581 Pa). No significant correlation was found between spleen stiffness and BMI, arterial mean blood pressure, age, spleen volume, and liver stiffness (all p > 0.05)
CONCLUSION. These preliminary results in a small number of healthy volunteers show that spleen stiffness is not significantly correlated with BMI, arterial mean blood pressure, spleen volume, or liver stiffness. A significant difference was observed using different driver positions.

Introduction

Portal venous hypertension is important in several clinical situations, particularly in patients with cirrhosis, where the degree of portal venous hypertension is correlated with the development and risk of bleeding of gastroesophageal varices [13]. Variceal hemorrhage is a major cause of morbidity and mortality in patients with cirrhosis, making monitoring and prophylactic treatment of portal venous hypertension an important issue [410].
Portal venous pressures can be measured directly only by use of invasive techniques, such as direct portal venography or direct splenic puncture. Currently, the most widely accepted and used measurement method is an indirect but invasive one—hepatic vein wedge pressure measurement [11]. This technique is considered safer than the direct methods but remains relatively impractical for serial monitoring or evaluating treatment response and is not widely used outside specialist hepatology centers.
Over the last four decades, indirect non-invasive markers have been investigated, including portal venous flow, splenic size, portal vein diameter, and platelet count [8, 9], but none of these markers has proven to be a reliable indicator of portal venous hypertension. Recently, the ability to measure organ stiffness noninvasively using ultrasound- or MRI-based elastography has provided an opportunity to investigate whether spleen stiffness is related to portal pressure [1, 1214]. Early studies have indicated a correlation [1, 14, 15], but to fully investigate this relationship, it is necessary to understand the normal range of splenic stiffness and to know whether this stiffness is influenced by other parameters, such as splenic volume, age, arterial mean blood pressure, or body mass index (BMI). There is little or no established literature on physical measurements of normal splenic stiffness, although in clinical medicine, many diseases are known to affect spleen size and stiffness, as determined by manual palpation.
The main aim of this work was to establish the range of normal splenic stiffness using MR elastography (MRE) in healthy adult volunteers and to demonstrate any correlation with age, BMI, blood pressure, or other parameters likely to influence the results in future studies of the technique in patients with portal venous hypertension. As a secondary aim, we evaluated two different MRE driver locations to see whether they influenced the stiffness measurements.

Subjects and Methods

Volunteers

This study was approved by the local ethics committee, and informed consent was obtained from the participants. Sixteen healthy volunteers (nine men and seven women; mean [± SD] age, 37 ± 9 years; age range, 28–56 years) with no history of gastrointestinal, hepatobiliary, or cardiovascular disease and with no history of splenic trauma who were not receiving any regular medication were recruited. The volunteers underwent imaging between October 22 and November 7, 2008. The studies were performed in the morning, and participants were asked to fast for at least the preceding 6 hours.
Fig. 1A 35-year-old man. Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on right, over liver. FIESTA image was used to choose location for MRE acquisition.
Fig. 1B 35-year-old man. Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on right, over liver. From gradient-echo MRE acquisition, magnitude images (B) and three sets of postprocessed images are displayed: stiffness color map (C), MRE inversion stiffness gray-scale image (D), and wave image (E). Stiffness measurements were made on images (D) in which gray scale reflects stiffness in Pascals. Regions of interest were drawn over spleen perimeter on gradient-echo magnitude images (B) and then copied and pasted on to matching MRE inversion stiffness images (D). Same procedure was used to measure liver stiffness.
Fig. 1C 35-year-old man. Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on right, over liver. From gradient-echo MRE acquisition, magnitude images (B) and three sets of postprocessed images are displayed: stiffness color map (C), MRE inversion stiffness gray-scale image (D), and wave image (E). Stiffness measurements were made on images (D) in which gray scale reflects stiffness in Pascals. Regions of interest were drawn over spleen perimeter on gradient-echo magnitude images (B) and then copied and pasted on to matching MRE inversion stiffness images (D). Same procedure was used to measure liver stiffness.
Fig. 1D 35-year-old man. Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on right, over liver. From gradient-echo MRE acquisition, magnitude images (B) and three sets of postprocessed images are displayed: stiffness color map (C), MRE inversion stiffness gray-scale image (D), and wave image (E). Stiffness measurements were made on images (D) in which gray scale reflects stiffness in Pascals. Regions of interest were drawn over spleen perimeter on gradient-echo magnitude images (B) and then copied and pasted on to matching MRE inversion stiffness images (D). Same procedure was used to measure liver stiffness.
Fig. 1E 35-year-old man. Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on right, over liver. From gradient-echo MRE acquisition, magnitude images (B) and three sets of postprocessed images are displayed: stiffness color map (C), MRE inversion stiffness gray-scale image (D), and wave image (E). Stiffness measurements were made on images (D) in which gray scale reflects stiffness in Pascals. Regions of interest were drawn over spleen perimeter on gradient-echo magnitude images (B) and then copied and pasted on to matching MRE inversion stiffness images (D). Same procedure was used to measure liver stiffness.

Physiologic Parameters

The age and sex of the participants were recorded, and their arterial systolic blood pressure (SP) and diastolic blood pressure (DP) were measured immediately after the examination with the volunteer still supine on the scanner table using an electronic manometer (3,150 MRI magnitude; IN VIVO, Research Inc.) and a left arm cuff. The arterial mean blood pressure (AMBP) was calculated according to a formula published elsewhere [16]: AMBP ≈ [(2 × DP) + SP] / 3. Volunteers' weight and height were also measured immediately after the examination using an electronic balance with incorporated a height meter (SECA, Balance Technology). The BMI was calculated as follows: BMI = weight (kg) / height2 (m2).

MRI

MRI was performed using a commercial whole-body 1.5-T MRI system (Signa HDx, GE Healthcare) using an eight-element cardiac receive coil.

Conventional MRI

After initial T2-weighted localizer images were obtained, 20 contiguous axial balanced gradient-echo images (FIESTA) with 10-mm-thick sections were obtained through the upper abdomen encompassing the spleen during a single breath-hold, using the following parameters: TR/TE, 3.2/1.4; field of view, 360 × 288 mm; number of averages, 1; and matrix, 192 × 384. On the basis of these images, a 19-cm diameter pneumatic membrane driver [12] was placed first on the right side over the anterior abdominal wall at the axial level of the midpoint of the craniocaudal extent of the spleen. Subsequently, the driver was repositioned at the same axial level but in a left anterior position, close to the actual spleen location.

MRE

Two separate breath-hold MRE acquisitions were performed in the transverse plane with the driver first in a right anterior and second in a left anterior abdominal wall position. A gradient-echo-based MRE sequence was used with the following parameters: TR/TE, 99.9/24.8; field of view, 360 × 270 mm; matrix, 256 × 96; two sections 10 mm thick and 10 mm apart; number of averages, 1; and 60-Hz excitation.
The MRE images were processed using a local frequency estimation inversion algorithm that has been previously developed and described elsewhere [17], to obtain stiffness maps. The processing generates several images at each of the two locations, including a conventional magnitude image, and a gray-scale stiffness local frequency estimation image.

MRI Evaluation

Conventional MRI evaluation—Two abdominal MR radiologists independently reviewed the images using a commercial workstation (Advantage 4.4 for Windows, GE Healthcare) and measured the splenic volumes using planimetry on the sequential FIESTA images. The radiologist used manually drawn regions of interests to outline the spleen borders. The total outlined surface was multiplied by the slice thickness to calculate the splenic volume.
MRE imaging evaluation—There were no technical problems in imaging any of the volunteers' spleens. The waves were well visualized in all of the spleens.
The same two radiologists measured the organ stiffness values on the MRE images by manually placing regions of interest outlining the organ margins on the two axial sections of the gradient-echo magnitude images, which were then mapped onto the matching MRE inversion stiffness images. The organ stiffness values (in Pascals) were calculated as the averaged mean of the two sections. Both radiologists evaluated the spleen stiffness using the left driver position and the liver stiffness using the right driver position. In addition, one radiologist repeated this procedure for the spleen using the right driver position and for the liver using the left driver position. Hence, a total of six sets of measurements were obtained for the spleen and liver stiffness: for reader 1, spleen right, spleen left, liver right, and liver left; and for reader 2, spleen left and liver right.
Fig. 2A 35-year-old man (same volunteer as in Figure 1A, 1B, 1C, 1D, 1E). Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on left, over spleen. Stiffness values were obtained using same procedure as described in Figure 1A, 1B, 1C, 1D, 1E. FIESTA image.
Fig. 2B 35-year-old man (same volunteer as in Figure 1A, 1B, 1C, 1D, 1E). Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on left, over spleen. Stiffness values were obtained using same procedure as described in Figure 1A, 1B, 1C, 1D, 1E. Magnitude image.
Fig. 2C 35-year-old man (same volunteer as in Figure 1A, 1B, 1C, 1D, 1E). Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on left, over spleen. Stiffness values were obtained using same procedure as described in Figure 1A, 1B, 1C, 1D, 1E. Stiffness color map.
Fig. 2D 35-year-old man (same volunteer as in Figure 1A, 1B, 1C, 1D, 1E). Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on left, over spleen. Stiffness values were obtained using same procedure as described in Figure 1A, 1B, 1C, 1D, 1E. MRE inversion stiffness gray-scale image.
Fig. 2E 35-year-old man (same volunteer as in Figure 1A, 1B, 1C, 1D, 1E). Balanced gradient-echo (FIESTA) and MR elastography (MRE) images were obtained with driver placed anteriorly on left, over spleen. Stiffness values were obtained using same procedure as described in Figure 1A, 1B, 1C, 1D, 1E. Wave image.

Statistical Analysis

The relationship of MRE spleen and liver stiffness measurements to the position of the pneumatic membrane driver was evaluated formally using a paired Student's t test. Sex differences in spleen and liver stiffness measurements were tested using an unpaired Student's t test. The assumptions required to perform the Student's t tests (equal variance and a normal distribution) were tested using an F test and a Shapiro-Wilks test, respectively.
The correlation between the measured spleen and liver stiffness values (reader 1, spleen left and liver right) and the physiologic parameters (age, BMI, arterial mean blood pressure, and spleen volume) was tested using the nonparametric Spearman's rank correlation method. In addition, the correlation between reader 1's left spleen and right liver measurements was evaluated. A p value of < 0.05 was defined as statistically significant; however, to account for the multiple comparisons performed, a Bonferroni correction was applied so that the result was defined as significant if p < 0.05/13, or p < 0.004. The interobserver agreement between spleen (left spleen measurement for both readers) and the liver stiffness values (right liver measurements for both readers) was assessed using a one-way intraclass correlation coefficient (ICC) model.

Results

Figures 1A, 1B, 1C, 1D, 1E and 2A, 2B, 2C, 2D, 2E show typical MRE images of the same volunteer with the driver placed on both the right and left sides of the abdomen. Figure 3A, 3B, 3C, 3D, 3E displays the plots of the MRE values against the other parameters with correlation coefficients as listed. These figures use the right driver location for the liver measurements and the left driver location for the spleen measurements, both obtained by reader 1. With the driver placed on the right side, the mean spleen stiffness determined by reader 1 for the group was 3,565 ± 586 Pa (range, 2,353–4,442 Pa); with the driver on the left side, the spleen stiffness measured by reader 1 was 4,255 ± 625 Pa (range, 3,194–5,581 Pa). There was a significant difference in the spleen stiffness measurements obtained using the two driver positions (p < 0.001) (Figs. 4 and 5). The mean liver stiffness, as determined by reader 1 with the right driver position, was 3,014 ± 279 Pa (range, 2,574–3,622 Pa), and that determined by reader 1 using the left position was 2,825 ± 326 Pa (range, 2,404–3,372 Pa); these results were not significantly different (p = 0.089).
Fig. 3A Relationship between liver and spleen stiffness and physiologic measurements. Plots show relationships between liver and spleen stiffness and body mass index (BMI) (A), arterial mean blood pressure (AMBP) (B), spleen volume (C), and age (D) (all p > 0.004).
Fig. 3B Relationship between liver and spleen stiffness and physiologic measurements. Plots show relationships between liver and spleen stiffness and body mass index (BMI) (A), arterial mean blood pressure (AMBP) (B), spleen volume (C), and age (D) (all p > 0.004).
Fig. 3C Relationship between liver and spleen stiffness and physiologic measurements. Plots show relationships between liver and spleen stiffness and body mass index (BMI) (A), arterial mean blood pressure (AMBP) (B), spleen volume (C), and age (D) (all p > 0.004).
Fig. 3D Relationship between liver and spleen stiffness and physiologic measurements. Plots show relationships between liver and spleen stiffness and body mass index (BMI) (A), arterial mean blood pressure (AMBP) (B), spleen volume (C), and age (D) (all p > 0.004).
Fig. 3E Relationship between liver and spleen stiffness and physiologic measurements. Relationship between spleen and liver stiffness is plotted (p > 0.004).
Splenic volumes ranged from 12.2 to 42.7 mL (mean, 23.1 ± 8.2 mL), BMI ranged from 22.2 to 32.4 kg/m2 (mean, 26.3 ± 3.2 kg/m2), and mean arterial blood pressure ranged from 68 to 102 mm Hg (mean, 83 ± 9 mm Hg). There was no significant correlation using any combination of driver location between spleen and liver stiffness (reader 1, liver right and spleen left drivers: r = 0.388; p = 0.137). The spleen stiffness had a moderately negative correlation with the volunteers' age (r = –0.514; p = 0.042), but this correlation was not significant after the Bonferroni correction. There was no significant correlation between spleen stiffness and the volunteers' BMI, arterial mean blood pressure, and spleen volume (all p > 0.05). There was also no significant correlation between the liver stiffness and the volunteers' age, spleen volume, and arterial mean blood pressure (all p > 0.05), but there was a borderline correlation between the volunteers' BMI and the liver stiffness (r = 0.674; p = 0.005).
A difference in liver and spleen stiffness was observed between the sexes. The spleen stiffness values were higher for men than for women (men, 4.56 ± 0.59 kPa; women, 3.86 ± 0.44 kPa; p = 0.017). Similarly, men had a higher degree of liver stiffness than women did (men, 3.14 ± 0.26 kPa; women, 2.86 ± 0.23 kPa; p = 0.038). However, after application of the Bonferroni correction, the sex-associated differences were not statistically significant (p > 0.004).
Reader 2's measurements were as follows: mean splenic stiffness (left driver), 4,402 ± 784 Pa (range, 3,412–6,111 Pa); and mean liver stiffness (right driver), 3,041 ± 289 Pa (range, 2,578–3,625 Pa). There was good interobserver agreement for spleen measurements (ICC, 0.86; 95% CI, 0.65–0.95) and liver measurements (ICC, 0.98; 95% CI, 0.935–0.992).

Discussion

These preliminary results in a small number of healthy volunteers show that normal spleen stiffness values lie within a relatively small range and do not appear to be significantly correlated with BMI, arterial mean blood pressure, spleen volume, or liver stiffness. A nonsignificant trend was observed with age, and further evaluation of this trend requires a larger population study.
Fig. 4 Scatterplots show difference in spleen and liver stiffness measurements with driver location.
Fig. 5 Per volunteer paired stiffness values in spleen for two device locations. In all cases, values increase using left driver position.
The apparently normal range covering both driver locations used in this study was 2,353–5,581 Pa, a range that is substantially less than the preliminary spleen stiffness values reported elsewhere in cirrhotic patients [1, 12]. The results using the right anterior driver position are very similar to those observed in the only other similar published study [1, 12], which also used data with an excitation driver in the right anterior location.
Two driver locations were chosen for practical reasons because both are straightforward to achieve during a routine liver examination in a supine patient. This work unexpectedly showed that the driver location significantly influenced the splenic stiffness results (Figs. 4 and 5). The reasons for this are unclear but are likely related to the measurement technique, which uses a 2D method and relies on excitation waves passing orthogonally through the organ of interest. Although relatively low-frequency excitation was used, there is substantial wave amplitude attenuation with distance from the driver. Using the right anterior location, wave excitation passes through the liver before reaching the spleen, whereas in the left anterior location, wave excitation reaches the spleen more directly. The 2D inversion algorithm, originally optimized for liver measurements, ideally needs both a complete wave cycle within the structure of interest and sufficient signal-to-noise ratio to establish an accurate stiffness value. If one or both of these factors are compromised, then this may lead to an underestimation of the stiffness values in a structure surrounded by softer tissue materials. It would be expected that the left anterior location would perform better regarding both these factors because the excitation wave would be more likely to traverse a longer length of spleen (anteroposteriorly) and the closer physical location would generate larger wave amplitudes for the subsequent analysis. The lack of correlation between stiffness results and organ volume in this work suggests that, in this group of volunteers, any directional effect is not large.
A further confounding factor may be the presence of oblique waves generated by reflection off other body interfaces, such as the diaphragm, and passing through the spleen. These waves, if they pass obliquely through the 2D plane of the MRE measurement, will appear to the analysis algorithm as waves of longer wavelength than if they were perpendicular to the plane. This will, in turn, result in artifactually increased stiffness measurements. Intuitively, oblique wave errors are more likely to occur when the excitation location is further away from the organ being measured, thus allowing more complex wave paths to develop.
In our study, the reverse was found, with increased stiffness values found when the excitation location was closer to the spleen, suggesting that this effect may not be as important as the increased wave amplitudes available for the inversion algorithm. An alternative approach to evaluate these issues would be to use true 3D acquisition and analysis. Currently, this requires much longer acquisition times that are inappropriate for breath-holding, which increases the likelihood that additional artifacts through respiratory and gastrointestinal tract motion will be introduced.
In this study, we speculate that the left anterior driver location generates more accurate results. Further work is required to establish whether a single driver location would provide repeatable and accurate results for measurements of both spleen and liver stiffness; the difference in spleen stiffness values when measured from the right and left could, in fact, also be related to differences in reproducibility.
The liver stiffness values range was 2,404–3,625 Pa, which is within the mean liver stiffness reported in healthy volunteers using ultrasound-based elastography [1820] but higher than that reported in previous studies using MRE [21, 22]. Further work to assess reproducibility of MRE stiffness measurements is needed.
This study is limited by its small size and the lack of direct validation, which is not possible without an invasive measurement, which is difficult to ethically justify in volunteers. Such measurements are also likely to be compromised by other factors, such as anesthetic agents. It is currently not practical to simultaneously measure the portal venous pressure directly (or indirectly using hepatic vein wedge pressure) in humans at the same time as obtaining an MRE measurement, although this may be feasible in animals. Comparison with ultrasound-based transient elastography could be undertaken, but this technique itself is prone to sampling variation and also lacks direct validation. Further work is planned on technique repeatability and measurements in patients with suspected portal venous hypertension. Another limitation of this study is that the healthy status of the liver was not biopsy confirmed.
Despite the limitations outlined in the previous paragraph, the results obtained in this study indicate that, when using steady-state MRE with left-sided driver excitation, normal splenic stiffness values lie in the range of 3,194–5,581 Pa. These values are not significantly related to BMI, blood pressure, splenic volume, or liver stiffness; thus, these physiologic parameters are unlikely to represent confounding factors in serial spleen stiffness measurements in cirrhotic patients. The results suggest that use of a consistent MRE measurement technique would allow serial observation of splenic stiffness in patients with portal hypertension, which may provide, in the future, a noninvasive method for monitoring therapy response and identifying patients at risk of variceal hemorrhage.

Acknowledgments

We thank Addenbrooke's Charitable Trust and the NIHR Cambridge Biomedical Research Centre for funding support and Richard Ehman, of the MR Lab at Mayo Clinic, Minnesota, for loan of the elastography driver.

Footnotes

Presented as a traditional poster at the 2009 annual meeting of the International Society for Magnetic Resonance in Medicine, Honolulu, HI. Presented as an oral presentation at the 2009 annual meeting of the European Society of Gastrointestinal and Abdominal Radiology, Valencia, Spain (named one of the 20 best presentations).
This work was supported by Addenbrooke's Charitable Trust and the National Institute for Health Research Cambridge Biomedical Research Centre.
Address correspondence to L. Mannelli ([email protected]).

References

1.
Talwalkar JA, Yin M, Venkatesh S, et al. Feasibility of in vivo MR elastographic splenic stiffness measurements in the assessment of portal hypertension. AJR 2009; 193:122–127
2.
Groszmann RJ, Garcia-Tsao G, Bosch J, et al., for the Portal Hypertension Collaborative Group. Beta-blockers to prevent gastroesophageal varices in patients with cirrhosis. N Engl J Med 2005; 353:2254 –2261
3.
Garcia-Tsao G, D'Amico G, Abraldes JG, et al. Predictive models in portal hypertension. In: De Franchis R, ed. Portal hypertension IV: Proceedings of the Fourth Baveno International Consensus Workshop on methodology of diagnosis and treatment. Oxford, UK: Blackwell Publishing, 2006:47 –102
4.
D'Amico G, Pasta L, Madonia S, et al. The incidence of esophageal varices in cirrhosis. Gastroenterology 2001; 120[suppl 1]:A2
5.
De Franchis R. Evolving consensus in portal hypertension. Report of the Baveno IV consensus workshop on methodology of diagnosis and therapy in portal hypertension. J Hepatol 2005; 43:167–176
6.
Garcia-Tsao G. Current management of the complications of cirrhosis and portal hypertension: variceal hemorrhage, ascites, and spontaneous bacterial peritonitis. Gastroenterology 2001; 120:726 –748
7.
Garcia-Tsao G, Groszmann RJ, Fisher RL, Conn HO, Attenburry CE, Glickman M. Portal pressure, presence of gastroesophageal varices and variceal bleeding. Hepatology 1985; 5:419–424
8.
Groszmann RJ. Reassessing portal venous pressure measurements. Gastroenterology 1984; 86:1611 –1614
9.
Sen S, Griffiths WJH. Non-invasive prediction of oesophageal varices in cirrhosis. World J Gastroenterol 2008; 14:2454 –2455
10.
Qamar AA, Grace ND, Groszmann RJ, et al. for the Portal Hypertension Collaborative Group. Platelet count is not a predictor of the presence or development of gastroesophageal varices in cirrhosis. Hepatology 2008; 47:153–159
11.
Thalheimer U, Leandro G, Samonakis DN, Triantos CK, Patch D, Burroughs AK. Assessment of the agreement between wedge hepatic vein pressure and portal vein pressure in cirrhotic patients. Dig Liver Dis 2005; 37:601 –608
12.
Yin M, Talwalkar JA, Romano AJ, et al. Increased splenic stiffness: a potential indicator of portal hypertension. Proceedings of the International Society for Magnetic Resonance in Medicine annual meeting, 2007, 217.
13.
Rouvière O, Yin M, Dresner MA, et al. MR elastography of the liver: preliminary results. Radiology 2006; 240:440 –448
14.
Kim JK, Kim HS, Park YN, et al. Transient elastography: a new and useful non-invasive method in determination of endoscopic surveillance for oesophageal varices in hepatitis B related compensated cirrhosis. Hepatology 2006; 44 [suppl 1]:447A –448A
15.
Huwart L, Sempoux C, Salameh N, et al. Liver fibrosis: noninvasive assessment with MR elastography versus aspartate aminotransferase-to-platelet ratio index. Radiology 2007; 245:458–466
16.
Sesso HD, Stampfer MJ, Rosner B, et al. Systolic and diastolic blood pressure, pulse pressure, and mean arterial pressure as predictors of cardiovascular disease risk in men. Hypertension 2000; 36:801 –807
17.
Manduca A, Oliphant TE, Dresner MA, et al. Magnetic resonance elastography: non-invasive mapping of tissue elasticity. Med Image Anal 2001; 5:237 –254
18.
Del Poggio P, Colombo S. Is transient elastography a useful tool for screening liver disease? World J Gastroenterol 2009; 15:1409 –1414
19.
Roulot D, Czernichow S, Le Clésiau H, et al. Liver stiffness values in apparently healthy subjects: influence of gender and metabolic syndrome. J Hepatol 2008; 48:606–613
20.
Sirli R, Sporea I, Tudora A, et al. Transient elastographic evaluation of subjects without known hepatic pathology: does age change the liver stiffness? J Gastrointestin Liver Dis 2009; 18:57 –60
21.
Yin M, Talwalkar JA, Glaser KJ, et al. Assessment of hepatic fibrosis with magnetic resonance elastography. Clin Gastroenterol Hepatol 2007; 5:1207 –1213
22.
Venkatesh SK, Yin M, Glockner JF, et al. MR elastography of liver tumors: preliminary results. AJR 2008; 190:1534 –1540

Information & Authors

Information

Published In

American Journal of Roentgenology
Pages: 387 - 392
PubMed: 20651194

History

Submitted: July 27, 2009
Accepted: December 31, 2009

Keywords

  1. cirrhosis
  2. MR elastography
  3. portal hypertension
  4. spleen
  5. stiffness

Authors

Affiliations

Lorenzo Mannelli
All authors: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Hills Rd., Cambridge, CB2 0QQ, United Kingdom.
Edmund Godfrey
All authors: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Hills Rd., Cambridge, CB2 0QQ, United Kingdom.
Ilse Joubert
All authors: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Hills Rd., Cambridge, CB2 0QQ, United Kingdom.
Andrew J. Patterson
All authors: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Hills Rd., Cambridge, CB2 0QQ, United Kingdom.
Martin J. Graves
All authors: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Hills Rd., Cambridge, CB2 0QQ, United Kingdom.
Ferdia A. Gallagher
All authors: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Hills Rd., Cambridge, CB2 0QQ, United Kingdom.
David J. Lomas
All authors: Department of Radiology, Addenbrooke's Hospital and University of Cambridge, Hills Rd., Cambridge, CB2 0QQ, United Kingdom.

Metrics & Citations

Metrics

Citations

Export Citations

To download the citation to this article, select your reference manager software.

Articles citing this article

View Options

View options

PDF

View PDF

PDF Download

Download PDF

Media

Figures

Other

Tables

Share

Share

Copy the content Link

Share on social media