How accurate are measurements on MRI? a study on multiple sclerosis using reliable 3D stereological methods

Gadeberg, Paula; Gundersen, Hans Jørgen G.; Tågehøj, Finn

doi:10.1002/(sici)1522-2586(199907)10:1<72::aid-jmri10>3.3.co;2-h

Cited by 10 publications

(13 citation statements)

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“…The overestimation was worse for POP with higher amounts of CS (2 g/L and 3 g/L) because the signal intensity increases as more contrast agent is used. This results in overprojection of the section thickness, i.e., more voxels light up at the boundary of the object [38]. Silicone gel diameter was underestimated in MRI in both the x and y directions, and polyurethane diameter was underestimated in the y direction but overestimated in the x direction.…”

Section: Discussionsupporting

confidence: 82%

Examination of anticipated chemical shift and shape distortion effect on materials commonly used in prosthetic socket fabrication when measured using MRI: A validation study

Safari¹,

Rowe²,

Buis³

2013

JRRD

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Abstract-The quality of lower-limb prosthetic socket fit is influenced by shape and volume consistency during the residual limb shape-capturing process (i.e., casting). Casting can be quantified with magnetic resonance imaging (MRI) technology. However, chemical shift artifact and image distortion may influence the accuracy of MRI when common socket/casting materials are used. We used a purpose-designed rig to examine seven different materials commonly used in socket fabrication during exposure to MRI. The rig incorporated glass marker tubes filled with water doped with 1 g/L copper sulfate (CS) and 9 plastic sample vials (film containers) to hold the specific material specimens. The specimens were scanned 9 times in different configurations. The absolute mean difference of the glass marker tube length was 1.39 mm (2.98%) (minimum = 0.13 mm [0.30%], maximum = 5.47 mm [14.03%], standard deviation = 0.89 mm). The absolute shift for all materials was <1.7 mm. This was less than the measurement tolerance of +/-2.18 mm based on voxel (three-dimensional pixel) dimensions. The results show that MRI is an accurate and repeatable method for dimensional measurement when using matter containing water. Additionally, silicone and plaster of paris plus 1 g/L CS do not show a significant shape distortion nor do they interfere with the MRI image of the residual limb.

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Section: Discussionsupporting

confidence: 82%

Examination of anticipated chemical shift and shape distortion effect on materials commonly used in prosthetic socket fabrication when measured using MRI: A validation study

Safari¹,

Rowe²,

Buis³

2013

JRRD

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“…Correspondingly, only 11 out of 50 imaging studies found reduced whole brain volume in schizophrenia (Shenton et al, 2001); however, all 11 of the positive studies were based upon chronic patients, while 10 of the negative studies were based upon subjects in their first episode of schizophrenia. In addition, it is not clear to what degree the inconsistency of the MRI findings reflects methodological limitations; assessments of accuracy of MRI-based volume estimates suggest that significant biases may be present (Gadeberg et al, 1999(Gadeberg et al, , 2002Garcia-Fiñana et al, 2003). Assuming it exists, this small difference could to some degree be caused by medication effects like the one observed in this study; however, it appears that a medication-induced difference in whole brain size of a magnitude comparable to the B10% seen in our study does not occur, in general, in individuals with schizophrenia treated with antipsychotic drugs.…”

Section: Implication For Studies Of Schizophreniamentioning

confidence: 99%

The Influence of Chronic Exposure to Antipsychotic Medications on Brain Size before and after Tissue Fixation: A Comparison of Haloperidol and Olanzapine in Macaque Monkeys

Dorph‐Petersen

Pierri

Perel

et al. 2005

Neuropsychopharmacol

373

250

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It is unclear to what degree antipsychotic therapy confounds longitudinal imaging studies and post-mortem studies of subjects with schizophrenia. To investigate this problem, we developed a non-human primate model of chronic antipsychotic exposure. Three groups of six macaque monkeys each were exposed to oral haloperidol, olanzapine or sham for a 17-27 month period. The resulting plasma drug levels were comparable to those seen in subjects with schizophrenia treated with these medications. After the exposure, we observed an 8-11% reduction in mean fresh brain weights as well as left cerebrum fresh weights and volumes in both drug-treated groups compared to sham animals. The differences were observed across all major brain regions (frontal, parietal, temporal, occipital, and cerebellum), but appeared most robust in the frontal and parietal regions. Stereological analysis of the parietal region using Cavalieri's principle revealed similar volume reductions in both gray and white matter. In addition, we assessed the subsequent tissue shrinkage due to standard histological processing and found no evidence of differential shrinkage due to drug exposure. However, we observed a pronounced general shrinkage effect of B20% and a highly significant variation in shrinkage across brain regions. In conclusion, chronic exposure of non-human primates to antipsychotics was associated with reduced brain volume. Antipsychotic medication may confound post-mortem studies and longitudinal imaging studies of subjects with schizophrenia that depend upon volumetric measures.

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“…Furthermore, PVE increases if the object analyzed is very irregular in shape (21). Other studies have reported an overestimation of 10% or more when volume of different objects are measured using imaging modalities (19,20). We did not experience influences of PVE in the acquired images, which may be explained by the fact that the kidney is regular in shape, quite large, and acquisitions were performed using thin slices.…”

Section: Discussionmentioning

confidence: 62%

“…This would potentially result in an overestimation of Vc. Gadeberg et al (19) showed that the impact of PVE depends on the slice thickness and the diameter of the object investigated; hence, the thinner the slices and the larger the diameter, the smaller the PVE (19,20). Furthermore, PVE increases if the object analyzed is very irregular in shape (21).…”

Section: Discussionmentioning

confidence: 99%

Different strategies for MRI measurements of renal cortical volume

Karstoft

Lødrup

Dissing

et al. 2007

Magnetic Resonance Imaging

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Purpose: First, to measure renal cortical volume (Vc) using different MRI methods combined with a semiautomatic segmentation method. Second, to compare MRI measurements of Vc using the semiautomatic segmentation method with a manual segmentation method. Third, to evaluate the reproducibility of Vc measurements. Materials and Methods:A total of 22 pigs, 13 with healthy kidneys and nine with diseased kidneys, underwent MRI with two non-contrast-agent methods (MRI 100ϫ900 and MRI 300ϫ1100 ) and one contrast-agent method (MRI Gd ). For each of these methods, Vc was estimated using semiautomatic (Vc 100ϫ900 , Vc 300ϫ1100 , and Vc Gd ), as well as manual (Vc MANUAL ) segmentation. Reference volumes were estimated by stereological means (Vc STEREOLOGY ). MRI-derived volumes were compared with reference volumes using a two-tailed paired t-test, and variances between methods were visualized with Bland Altman plots. Reproducibilities were analyzed using covariance analysis.Results: Neither measurements of Vc 100ϫ900 , Vc 300ϫ1100 , nor Vc Gd differed markedly from Vc STEREOLOGY using semiautomatic segmentation. Vc was comparable when semiautomatic and manual segmentations were performed at the same scan. Reproducibility of MRI estimated Vc values offered intra-and interindividual differences Ͻ5%. Conclusion:Vc can in both healthy and diseased kidneys be measured accurately with MRI using both semiautomatic and manual segmentation, and measurements can be obtained with a high reproducibility. Measurements of Vc 100ϫ900 may in the future become suitable in patients with chronic renal failure.

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How accurate are measurements on MRI? a study on multiple sclerosis using reliable 3D stereological methods

Cited by 10 publications

References 0 publications

Examination of anticipated chemical shift and shape distortion effect on materials commonly used in prosthetic socket fabrication when measured using MRI: A validation study

Examination of anticipated chemical shift and shape distortion effect on materials commonly used in prosthetic socket fabrication when measured using MRI: A validation study

The Influence of Chronic Exposure to Antipsychotic Medications on Brain Size before and after Tissue Fixation: A Comparison of Haloperidol and Olanzapine in Macaque Monkeys

Different strategies for MRI measurements of renal cortical volume

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