Two simple and rapid methods based on maximum diameter accurately estimate large lesion volumes in acute stroke.

BACKGROUND: We compared two simple and rapid diameter-based methods (ABC/2, od-value) in terms of their accuracy in predicting lesion volume >70 ml and >100 ml. METHODS: In 238 DWI images of ischemic stroke patients from the AXIS2 trial, maximum lesion diameter and corresponding maximum orthogonal diameter were measured. Estimation of infarct volume based on od-value and ABC/2 calculation was compared to volumetric assessments. RESULTS: Accuracy of od-value and ABC/2 was similar for >70 ml (92.0 vs. 87.4) and >100 ml (92.9 vs. 93.3). ABC/2 overestimated lesion volume by 29.9%, resulting in a lower specificity. CONCLUSIONS: Od-value is a robust tool for patient selection in trials.

Combined morphological and functional liver MRI using spin-lattice relaxation in the rotating frame (T1ρ) in conjunction with Gadoxetic Acid-enhanced MRI.

Noninvasive early detection of liver cirrhosis and fibrosis is essential for management and therapy. The aim was to investigated whether a combination of the functional parameter relative enhancement (RE) on Gadoxetic Acid magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) and the fibrosis parameter T1ρ distinguishes cirrhosis and healthy liver. We analyzed patients with Gd-EOB-DTPA-enhanced MRI and T1ρ mapping. Signal intensity was measured before and after contrast; RE was calculated. T1ρ was measured with circular regions of interest (T1ρ-cROI). A quotient of RE and T1ρ-cROI was calculated: the fibrosis function quotient (FFQ). Cirrhosis was evaluated based on morphology and secondary changes. 213 datasets were included. The difference between cirrhotic and noncirrhotic liver was 51.11 ms vs. 47.56 ms for T1ρ-cROI (p < 0.001), 0.59 vs. 0.70 for RE (p < 0.001), and 89.53 vs. 70.83 for FFQ (p < 0.001). T1ρ-cROI correlated with RE, r = -0.14 (p < 0.05). RE had an AUC of 0.73. The largest AUC had the FFQ with 0.79. The best cutoff value was 48.34 ms for T1ρ-cROI, 0.70 for RE and 78.59 ms for FFQ. In conclusion T1ρ and RE can distinguish between cirrhotic and noncirrhotic liver. The FFQ, which is the combination of the two, improves diagnostic performance.

Reliability of Two Diameters Method in Determining Acute Infarct Size. Validation as New Imaging Biomarker.

BACKGROUND: In order to select patients most likely to benefit for thrombolysis and to predict patient outcome in acute ischemic stroke, the volumetric assessment of the infarcted tissue is used. However, infarct volume estimation on Diffusion weighted imaging (DWI) has moderate interrater variability despite the excellent contrast between ischemic lesion and healthy tissue. In this study, we compared volumetric measurements of DWI hyperintensity to a simple maximum orthogonal diameter approach to identify thresholds indicating infarct size >70 ml and >100 ml. METHODS: Patients presenting with ischemic stroke with an NIHSS of ≥ 8 were examined with stroke MRI within 24 h after symptom onset. For assessment of the orthogonal DWI lesion diameters (od-values) the image with the largest lesion appearance was chosen. The maximal diameter of the lesion was determined and a second diameter was measured perpendicular. Both diameters were multiplied. Od-values were compared to volumetric measurement and od-value thresholds identifying a lesion size of > 70 ml and > 100 ml were determined. In a selected dataset with an even distribution of lesion sizes we compared the results of the od value thresholds with results of the ABC/2 and estimations of lesion volumes made by two resident physicians. RESULTS: For 108 included patients (53 female, mean age 71.36 years) with a median infarct volume of 13.4 ml we found an excellent correlation between volumetric measures and od-values (r2 = 0.951). Infarct volume >100 ml corresponds to an od-value cut off of 42; > 70 ml corresponds to an od-value of 32. In the compiled dataset (n = 50) od-value thresholds identified infarcts > 100 ml / > 70 ml with a sensitivity of 90%/ 93% and with a specificity of 98%/ 89%. The od-value offered a higher accuracy in identifying large infarctions compared to both visual estimations and the ABC/2 method. CONCLUSION: The simple od-value enables identification of large DWI lesions in acute stroke. The cutoff of 42 is useful to identify large infarctions with volume larger than 100 ml. Further studies can analyze the therapeutic utility of this new method. TRAIL REGISTRATION: ClinicalTrials.org NCT00715533.