Tomographic slices of a cholangiocellular carcinoma in a liver with macrosteatosis and pilosis filtered with the 3D bilateral filter.

<p>Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively. (F) shows the histogram of the filtered absorption image (top) and the filtered phase-contrast image (bottom) with red dashed lines marking the window level in the shown slices. The absorption images (A, D) profit strongly from the filtering, but the information is still complementary.</p

Filtered tomographic slices of a metastasis of a low-grade adenocarcinoma in a steatotic liver filtered with the 3D bilateral filter.

<p>Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively. (F) shows the histogram of the filtered absorption image (top) and the filtered phase-contrast image (bottom) with red dashed lines marking the window level in the shown slices.</p

Comparison of unfiltered and filtered tomographic slices of a metastasis of a low-grade adenocarcinoma in a steatotic liver.

<p>Axial slices of the conventional absorption-based (A, D) and the phase-contrast (B, E) tomography windowed using the same window level and window width. The histograms of both unfiltered (C) and filtered (F) tomographic datasets demonstrate the filtering result and the red dashed markers show the window level. The areas I (red, surrounding formalin) and II (blue, high-contrast tumor in (B) mark the regions of 30×30 pixels, which were averaged for CNR calculation.</p

Filtered tomographic slices of a hepatocellular carcinoma in a cirrhotic liver.

<p>The patient had received transcatheter arterial chemoembolisation (TACE). Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively, and (F) shows the histogram of the absorption (top) and the phase-contrast image (bottom) with red dashed lines marking the window level. In the absorption images (A, D) the HCC nodules in the right center (marked with red arrows in A) are visible due to the high density of the retained Lipiodol. In the phase-contrast images (B, D) the fibrous septa are visible as high signal bands whereas the liver tissue and the HCC nodules show intermediate signal. Some areas with increased Lipiodol retention show low signal.</p

Filtered tomographic slices of a subcapsular hematoma.

<p>Conventional absorption- based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively, and the histogram (F) of the absorption (top) and the phase-contrast image (bottom) show the window level as red dashed lines. In the absorption images (A, D) the contrast between the liver tissue in the upper right part of the image (A, D) and the subcapsular hematoma in the lower left part is considerably lower compared to the phase-contrast image (B, E) where the hematoma shows a high signal.</p

Filtered tomographic slices of a liver metastasis of a mucinous adenocarcinoma of the colon.

<p>Conventional absorption-based (A, D) and phase-contrast (B, E) CT images of the liver specimen in two different planes. H&E stain (C) corresponds to image A and B, respectively, and (F) shows the histograms of both signals with red dashed lines marking the window level. In the absorption images (A, C) only the mucinous parts of the metastasis are visible as areas with low density. The phase-contrast images (B, E) show a significantly higher soft-tissue contrast with low signal in the mucinous areas, intermediate signal in the liver tissue and higher signal for the tumor tissue and necrotic/hemorrhagic areas.</p

Comparison of CNRs for unfiltered and filtered tomographic slices of a metastasis of a low-grade adenocarcinoma in a steatotic liver shown in Figure 2.

<p>For the calculation of the CNRs the areas I (red, surrounding formalin) and II (blue, high-contrast tumor) marked in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083369#pone-0083369-g002" target="_blank">Figure 2B</a> were used, which correspond to 30×30 pixels.</p