## 3 Results
The use of the modified ellipse-based formula (with \(be\)) produced a renal parenchymal area \(A\epsilon\) that was no different from \(Am\) (Figure 8). Figure 5: Aristolochic acid + NaCl-induced kidney disease in mice. Representative photomicrograph (4X) of Masson’s Trichrome-stained kidneys from a control CD-1 mouse (**A**) and an aristolochic acid + NaCl-administered CD-1 mouse (**B**). Renal interstitial scarring is clearly evident in the latter. Figure 6: Renal parenchymal area in healthy and diseased mice (aristolochic acid + NaCl). Left and right kidneys were sourced from healthy adult male CD-1 mice or adult male CD-1 mice with aristolochic acid + NaCl nephropathy. (**A**) In coronal left kidney slices, \(Am\) is greater than \(A\) (\(\lx@math@degree\), \(p<0.01\)) but not different from \(A\epsilon\). (**B**) In coronal right kidney slices, \(Am\) is greater than \(A\) (\(\lx@math@degree\), \(p<0.01\)) but not different from \(A\epsilon\). Data from these models are summarized in Table 2. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Model**} & \multirow{2}{*}{**Kidney**} & **Elliptical (\%** & **Modified Elliptical (\%** \\  & & **Measured)** & **Measured)** \\ \hline \multirow{2}{*}{Healthy and Diseased Rat} & Left & 87.5 * & 101.6 \\ \cline{2-4}  & Right & 85 * & 99 \\ \hline \multirow{2}{*}{Aristolochic Mice} & Left & 84 * & 97.5 \\ \cline{2-4}  & Right & 87 * & 102 \\ \hline Aristolochic + Blinded Mice & Right & 87 * & 98 \\ \hline \multirow{2}{*}{STZ Mice} & Left & 86.5 * & 97 \\ \cline{2-4}  & Right & 87 * & 96 \\ \hline \hline \end{tabular}
* *, \(p\) < 0.05 vs. measured parenchymal area.  
\end{table} 
Table 2: Summary of calculated parenchymal areas as a percentage of the measured area using the elliptical formula and the modified elliptical formula. Figure 8: Renal parenchymal area in healthy and diseased mice (STZ + NaCl). Left and right kidneys were sourced from healthy adult male and female SV129 mice or adult male and female SV129 mice with diabetic nephropathy. (**A**) In coronal left kidney slices, \(Am\) is greater than \(A\) (*, \(p\) < 0.01) but not different from \(Ae\). (**B**) In coronal right kidney slices, \(Am\) is greater than \(A\) (*, \(p\) < 0.01) but not different from \(Ae\). Figure 7: Streptocozocin (STZ) + NaCl-induced kidney disease in mice. Representative photomicrograph (4\(\times\)) of [PERSON]’s Trichrome-stained kidneys from a control 129/Sv mouse (**A**) and an STZ + NaCl-administered 129/Sv mouse (**B**). Acute tubular necrosis and renal interstitial scarring is clearly evident in the latter. To determine whether use of the modified axial measurement translates to increased accuracy in calculating TKV, kidneys from SD rats and PCK rats (Figure 9) were examined. The volume of kidneys from adult male SD and adult male and female PCK rats determined by the fluid displacement methods spanned an 11-fold range, a range consistent with the range exhibited with clinical samples [19]. Kidney volumes calculated using the existing formula yielded a volume that was on average 87% of measured TKV (\(p<0.01\)). By contrast, use of the modified formula yielded a kidney volume in agreement (\(p=0.65\)) with measured TKV (Figure 9).