scholarly journals Interobserver and intraobserver variability of the apparent diffusion coefficient in treated malignant hepatic lesions on a 3.0T machine: Measurements in the whole lesion versus in the area with the most restricted diffusion

2010 ◽  
Vol 32 (3) ◽  
pp. 647-653 ◽  
Author(s):  
Tri-Linh C. Lu ◽  
Reto A. Meuli ◽  
Pedro M. Marques-Vidal ◽  
Pierre Bize ◽  
Alban Denys ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Restricted Diffusion ◽  
Intraobserver Variability ◽  
Apparent Diffusion ◽  
Hepatic Lesions

scholarly journals Utility of tubular retractors to minimize surgical brain injury in the removal of deep intraparenchymal lesions: a quantitative analysis of FLAIR hyperintensity and apparent diffusion coefficient maps

2016 ◽  
Vol 124 (4) ◽  
pp. 1053-1060 ◽  
Author(s):  
Evan D. Bander ◽  
Samuel H. Jones ◽  
Ilhami Kovanlikaya ◽  
Theodore H. Schwartz
Keyword(s):  
Diffusion Coefficient ◽  
Brain Injury ◽  
Apparent Diffusion Coefficient ◽  
Brain Lesions ◽  
Restricted Diffusion ◽  
Cellular Damage ◽  
Total Resection ◽  
Tubular Retractor ◽  
Apparent Diffusion ◽  
Apparent Diffusion Coefficient Maps

OBJECT Brain retraction systems are frequently required to achieve surgical exposure of deep-seated brain lesions. Spatula-based systems can be associated with injury to the cortex and deep white matter, particularly adjacent to the sharp edges, which can result in uneven pressure on the parenchyma over the course of a long operation. The use of tubular retractor systems has been proposed as a method to overcome these limitations. There have been no studies assessing the degree of brain injury associated with the use of tubular retractors. METHODS Twenty patients were retrospectively identified at Weill Cornell Medical College who underwent resection of deep-seated brain lesions between 2005 and 2014 with the aid of a METRx tubular retractor system. Using the Brainlab software, pre- and postoperative images were analyzed to assess volume, depth, extent of resection, and change in postoperative MR FLAIR hyperintensity and restricted diffusion on diffusion-weighted imaging (DWI). RESULTS The mean preoperative tumor volume was 16.25 ± 17.6 cm3. Gross-total resection was achieved in 75%, near-total resection in 10%, and subtotal resection in 15% of patients. There was a small but not statistically significant increase in average FLAIR hyperintensity volume by 3.25 ± 10.51 cm3 (p = 0.16). The average postoperative volume of DWI high signal area with restricted diffusion on apparent diffusion coefficient maps was 8.35 ± 3.05 cm3. Assuming that the volume of restricted diffusion on DWI around tumor was 0 preoperatively, this represented a statistically significant increase on DWI (p < 0.001). CONCLUSIONS Although tubular retractors do not appear to significantly increase FLAIR signal in the brain, DWI intensity around the retractors can be identified. These data indicate that although tubular retractors may minimize damage to surrounding tissues, they still cause cytotoxic edema and cellular damage. Objective comparison against other retraction methods, as compared by 3D volumetric analysis or similar methods, will be important in determining the true advantage of tubular retractor systems.

scholarly journals The Use of the Apparent Diffusion Coefficient (ADC) for Characterization and Differentiation of Focal Hepatic Lesions in Noncirrhotic Patients.

2021 ◽  
Author(s):  
Jonatan William Rodrigues Justo ◽  
Guilherme Watte ◽  
Bruno Hochhegger
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Focal Liver Lesions ◽  
Liver Lesions ◽  
Benign Lesions ◽  
Roc Curve Analysis ◽  
Adc Value ◽  
Apparent Diffusion ◽  
Focal Hepatic Lesions ◽  
Hepatic Lesions

Abstract PURPOSE Diffusion-weighted imaging (DWI) is a MRI technique that, although relatively recent, has shown promise for the evaluation of focal hepatic lesions, providing information both on qualitative and quantitative parameters. The present study was designed to analyze the role of DWI, particularly the ADC (apparent diffusion coefficient), in differentiating benign solid liver lesions from malignant ones in a sample of noncirrhotic patients. METHODS We conducted a retrospective analysis of MRI scans performed at a tertiary hospital in Porto Alegre, Rio Grande do Sul, Brazil, from 2015 to 2018. The distribution of lesions into benign vs. malignant groups was determined by imaging criteria and/or histological analysis. ADC were obtained for each lesion.RESULTS Overall, 118 focal liver lesions were evaluated, with 78 benign and 40 malignant. The mean ADC value was 1.420×10−3 mm2/s for benign lesions versus 1.130×10−3 mm2/s for malignant lesions (p<0.001). ROC curve analysis showed an area under the curve of 0.79, optimal cutoff point of 1.19×10−3 mm2/s for discriminating between malignant and benign lesions, sensitivity and specificity of 75% and 73.1%.CONCLUSIONS We demonstrate the appropriateness of ADC for characterization of benign solid lesions of the liver and to distinguish these masses from malignant metastatic lesions.

scholarly journals Cerebral Diffusion and T2: MRI Predictors of Acute Mountain Sickness during Sustained High-Altitude Hypoxia

2012 ◽  
Vol 33 (3) ◽  
pp. 372-380 ◽  
Author(s):  
John S Hunt ◽  
Rebecca J Theilmann ◽  
Zachary M Smith ◽  
Miriam Scadeng ◽  
David J Dubowitz
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Acute Mountain Sickness ◽  
Normal Subjects ◽  
Restricted Diffusion ◽  
Energy Status ◽  
Apparent Diffusion ◽  
Mountain Sickness ◽  
Magnetic Resonance Imaging Mri ◽  
Asymptomatic Subjects

Diffusion magnetic resonance imaging (MRI) provides a sensitive indicator of cerebral hypoxia. We investigated if apparent diffusion coefficient (ADC) and transverse relaxation (T2) predict symptoms of acute mountain sickness (AMS), or merely indicate the AMS phenotype irrespective of symptoms. Fourteen normal subjects were studied in two groups; unambiguous AMS and no-AMS at 3,800 m altitude (intermediate AMS scores were excluded). T2 relaxation was estimated from a T2 index of T2-weighted signal normalized by cerebrospinal fluid signal. Measurements were made in normoxia and repeated after 2 days sustained hypoxia (AMS group symptomatic and no-AMS group asymptomatic) and after 7 days hypoxia (both groups asymptomatic). Decreased ADC directly predicted AMS symptoms ( P < 0.05). Apparent diffusion coefficient increased in asymptomatic subjects, or as symptoms abated with acclimatization. This pattern was similar in basal ganglia, white matter, and gray matter. Corpus callosum behaved differently; restricted diffusion was absent (or rapidly reversed) in the splenium, and was sustained in the genu. In symptomatic subjects, T2,index decreased after 2 days hypoxia and further decreased after 7 days. In asymptomatic subjects, T2,index initially increased after 2 days, but decreased after 7 days. T2,index changes were not predictive of AMS symptoms. These findings indicate that restricted diffusion, an indicator of diminished cerebral energy status, directly predicts symptoms of AMS in humans at altitude.

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