The impact of three-dimensional tumor volume on cancer-specific survival for patients with pT1 clear-cell renal cell carcinoma

Improving accuracy, reliability, and efficiency of the RENAL nephrometry score with 3D reconstructed virtual imaging

OBJECTIVE

To clarify the diagnostic performance of the three-dimensional reconstructed virtual image (3D-RVI) in evaluating RENAL nephrometry score (RENAL-NS).

METHODS

This study included 130 patients who underwent preoperative contrast-enhanced computed tomography (CECT) followed by partial nephrectomy for renal tumors suggestive of renal cell carcinoma. RENAL-NS was calculated prior to the surgery, and tumor resection was performed referring to the score. We retrospectively reviewed preoperative CECT images. We calculated the inter-observer variability of RENAL-NS using 3D-RVI versus two-dimensional (2D) imaging and compared the ability of RENAL-NS using 3D-RVI versus 2D imaging to predict the risk of opening of the urinary collecting system. We also compared the two modalities for the time required to evaluate RENAL-NS.

RESULTS

RENAL-NS evaluated using 3D-RVI showed a higher inter-observer agreement compared to 2D-imaging (r_s = 0.85 vs. r_s = 0.65). The "nearness to sinus" score was more strongly associated with the opening of the urinary collecting system when evaluated using 3D-RVI than 2D-imaging (AUC = 0.71 vs AUC = 0.57, p = 0.016). RENAL-NS using 2D-imaging required a significantly longer time compared to 3D-RVI (p = 0.036).

CONCLUSIONS

Using 3D-RVI improves the accuracy, reliability and efficiency of RENAL-NS evaluation in preoperative assessment and can play an important role in preoperative assessment and intraoperative navigation.

Volumetric analysis at abdominal CT: oncologic and non-oncologic applications

Volumetric analysis is an objective three-dimensional assessment of a lesion or organ that may more accurately depict the burden of complex objects compared to traditional linear size measurement. Small changes in linear size are amplified by corresponding changes in volume, which could have significant clinical implications. Though early methods of calculating volumes were time-consuming and laborious, multiple software platforms are now available with varying degrees of user-software interaction ranging from manual to fully automated. For the assessment of primary malignancy and metastatic disease, volumetric measurements have shown utility in the evaluation of disease burden prior to and following therapy in a variety of cancers. Additionally, volume can be useful in treatment planning prior to resection or locoregional therapies, particularly for hepatic tumours. The utility of CT volumetry in a wide spectrum of non-oncologic pathology has also been described. While clear advantages exist in certain applications, some data have shown that volume is not always the superior method of size assessment and the associated labor intensity may not be worthwhile. Further, lack of uniformity among software platforms is a challenge to widespread implementation. This review will discuss CT volumetry and its potential oncologic and non-oncologic applications in abdominal imaging, as well as advantages and limitations to this quantitative technique.

Volume and Shape Assessment of Renal Radiofrequency Ablation Lesion

OBJECTIVE

To evaluate the microscopic characteristics and quantify the volume of a radiofrequency ablation (RFA) lesion.

METHODS

Ten male pigs were submitted to laparoscopic RFA. An RFA needle was introduced in the lower pole of the left kidney to create a lesion expected to be a sphere of 2.0 cm diameter. The animals were followed up for 21 days. Kidneys were weighed and the volume was assessed using Scherle's method. Cavalieri's principle was used to assess the RFA volume, and sphericity was calculated to assess RFA lesion. One sample t test was used to compare RFA volume with the volume of a sphere of 2.0 cm diameter, and sphericity to hypothetical values of a sphere and an icosahedron. Fragments of RFA region were histologically evaluated.

RESULTS

Three animals developed postoperative complications and were excluded from the analyses. There was no difference in the mean weight and volume between right and left kidneys following RFA. The mean total volume of RFA injury was 3.44 cm³. There was no difference in the RFA volume in comparison with hypothetical volumes of a sphere and an icosahedron of 2.0 cm diameter. Sphericity of the RFA injury was not similar with a sphere; however, it was similar to an icosahedron. Histology revealed areas of coagulation necrosis, fibrosis, and inflammatory mononuclear infiltration. Areas with normal tissue were also observed.

CONCLUSION

The volume of injury caused by RFA was as expected and its shape was comparable with an icosahedron. Microscopic evaluation revealed areas of normal-appearing tissue.