Tomokazu Umanodan, Presenter: Nothing to Disclose

Yoshihiko Fukukura MD, PhD, Abstract Co-Author: Nothing to Disclose

Junichi Ideue, Abstract Co-Author: Nothing to Disclose

Tomohide Yoneyama, Abstract Co-Author: Nothing to Disclose

Koji Takumi, Abstract Co-Author: Nothing to Disclose

Hiroto Hakamada, Abstract Co-Author: Nothing to Disclose

Masanori Nakajo MD, Abstract Co-Author: Nothing to Disclose

Masatoyo Nakajo MD, PhD, Abstract Co-Author: Nothing to Disclose

Megumi Jinguji, Abstract Co-Author: Nothing to Disclose

Takashi Yoshiura MD, PhD, Abstract Co-Author: Nothing to Disclose

To determine the diagnostic performance of intravoxel incoherent motion (IVIM) diffusion weighted imaging and histographic analysis of the apparent diffusion coefficient (ADC) for differentiating adrenal cortical adenomas from pheochromocytomas.

We retrospectively evaluated 35 adrenal tumors (24 cortical adenomas and 11 pheochromocytomas) in 34 patients (17 male and 17 female patients; mean age, 58.8 years; range, 16–86 years). The tumors were delineated by a free-hand region of interest (ROI) on each equatorial plane. The IVIM parameters (ADC, D, D*, and f) were obtained by using 10 b values (0, 10, 20, 30, 50, 80, 100, 200, 400, and 800 s/mm2). The histogram parameters of the ADC (b values of 0 and 200, 0 and 400, and 0 and 800 s/mm2), including the mean, variance, coefficient of variation (CV), kurtosis, skewness, and 10th, 25th, 50th, 75th, and 90th percentiles were calculated. The IVIM and histogram parameters were compared between cortical adenomas and pheochromocytomas by using the Mann-Whitney U test. Receiver operating characteristic curve analyses were used to assess the ability of the variance and CV of ADC derived from values of 0 and 800 s/mm2 for differentiating adrenal adenomas from pheochromocytomas. Sensitivity and specificity were calculated by using a threshold criterion that would maximize the average of sensitivity and specificity.

In ADC histogram analysis obtained at b values of 0 and 800 s/mm2, the variance and CV of cortical adenomas were significantly lower than those of pheochromocytomas (p=0.001 and 0.003, respectively). For cortical adenomas, the diagnostic sensitivities and specificities were 91.7% and 63.6% (cut off, <0.05) for the variance and were 70.8% and 81.8% (cut off, <0.17) for the CV. Any IVIM parameters were not significantly different.

The variance and CV of ADC (b values of 0 and 800s/mm2) are useful for distinguishing cortical adenomas from pheochromocytomas. The other histogram and IVIM parameters did not show significant differences.

Histogram analysis of diffusion-weighted magnetic resonance imaging can help differentiate adrenal cortical adenomas from pheochromocytomas.

Umanodan, T, Fukukura, Y, Ideue, J, Yoneyama, T, Takumi, K, Hakamada, H, Nakajo, M, Nakajo, M, Jinguji, M, Yoshiura, T, Intravoxel Incoherent Motion MRI and Histogram Analysis of the Apparent Diffusion Coefficient for the Differentiation between Adrenal Cortical Adenomas and Pheochromocytomas.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009100.html