Perfusion parameters were defined as follows: peak enhancement (maximum signal intensity reached during the transit of the bolus, expressed in % where 100% means the maximum), TTPceus (time of arrival of contrast agent post-injection to its maximum peak enhancement value).
With 110% or lower maximum enhancement ratio as the cutoff value, the positive predictive value for malignancy was 92% with a sensitivity of 63% and a specificity of 74%.
We assess the quantitative measurement of contrast agent enhancement as the difference between the baseline brightness before contrast agent injection and the value of maximum enhancement.
The maximum enhancement ratio and the slope value were higher in patients with VEGF-positive tumors than in patients with VEGF-negative tumors.
In summary, assessments of the maximum enhancement ratio and the slope value of dynamic MRI are helpful in differentiating benign SPNs (especially tuberculomas and hamartomas) and focal organizing pneumonias from lung cancers.
While focal organizing pneumonia is difficult to distinguish from lung cancer, we found that the maximum enhancement ratio and the slope value for the group of active infection and focal organizing pneumonias were higher than those for lung cancers and those for benign SPNs (tuberculomas and hamartomas) (Fig. 3) 20.
Some parametric pixel-by-pixel mapping, such as the mean and maximum enhancement ratios, show significantly higher values in cirrhosis than in normal livers [16].
The polarizing field B p was fixed to the value where the maximum enhancement was observed (Fig. 4).
Experiments in Japan show that the maximum enhancement for liquid Lithium occurs for values of the interaction parameter in the N=10 20 range.
In addition, the enhancement of Q value increases monotonously with the magnetic field and becomes remarkable when the applied magnetic field is beyond 50 mT. The maximum relative enhanced value of QR exceeds 6.8% in our experiments.
