Selective intra-arterial 3-dimensional computed tomography angiography for preoperative evaluation of nephron-sparing surgery

Three-dimensional printed model of bilateral Wilms tumor: A useful tool for planning nephron sparing surgery

Nephron sparing surgery (NSS) is increasingly utilized to treat patients with bilateral Wilms tumor. We present a case of NSS planning using a three-dimensional computerized and printed model of both kidneys with anatomical structures of interest (parenchyma, renal pelvis, major calyx, renal artery, renal vein, and tumor). This model allowed a better understanding of the anatomic relation between the tumor and the normal kidney on each side, improving the surgical planning and the preoperative discussion with the patient's family.

Advances of multidetector computed tomography in the characterization and staging of renal cell carcinoma

Renal cell carcinoma (RCC) accounts for approximately 90%-95% of kidney tumors. With the widespread use of cross-sectional imaging modalities, more than half of RCCs are detected incidentally, often diagnosed at an early stage. This may allow the planning of more conservative treatment strategies. Computed tomography (CT) is considered the examination of choice for the detection and staging of RCC. Multidetector CT (MDCT) with the improvement of spatial resolution and the ability to obtain multiphase imaging, multiplanar and three-dimensional reconstructions in any desired plane brought about further improvement in the evaluation of RCC. Differentiation of RCC from benign renal tumors based on MDCT features is improved. Tumor enhancement characteristics on MDCT have been found closely to correlate with the histologic subtype of RCC, the nuclear grade and the cytogenetic characteristics of clear cell RCC. Important information, including tumor size, localization, and organ involvement, presence and extent of venous thrombus, possible invasion of adjacent organs or lymph nodes, and presence of distant metastases are provided by MDCT examination. The preoperative evaluation of patients with RCC was improved by depicting the presence or absence of renal pseudocapsule and by assessing the possible neoplastic infiltration of the perirenal fat tissue and/or renal sinus fat compartment.

Perirenal fat invasion on renal cell carcinoma: evaluation with multidetector computed tomography-multivariate analysis

OBJECTIVE

The objective of this study was to assess the accuracy of multidetector computed tomography (CT) in diagnosing perinephric (PN) and/or renal sinus (RS) fat invasion in patients with renal cell carcinoma (RCC), with reference to the CT findings predictive for the diagnosis of invasion.

METHODS

This was a retrospective study of 48 RCCs. Examinations were performed on a 16-row CT scanner, including unenhanced and 3-phase contrast-enhanced CT scanning. Unenhanced transverse images and multiplanar reformations of each contrast-enhanced CT phase were evaluated. The predictive value of CT findings in diagnosing PN and/or RS fat invasion was determined using multivariate logistic regression analysis.

RESULTS

The CT findings that were most predictive for the diagnosis of PN fat invasion were the presence of contrast-enhancing nodules in the PN fat and tumoral margins. Invasion of the pelvicaliceal system was the most significant predictor in the diagnosis of RS fat invasion.

CONCLUSIONS

Multidetector CT provides satisfactory results in detecting PN and/or RS fat invasion in RCC.

Renal cell carcinoma: value of multiphase MDCT with multiplanar reformations in the detection of pseudocapsule

OBJECTIVE

The purpose of this study was to assess the diagnostic performance of four-phase (unenhanced, arterial, portal, and nephrographic-excretory) MDCT with multiplanar reformations in the detection of pseudocapsule of renal cell carcinoma (RCC).

MATERIALS AND METHODS

In a retrospective study of 29 histologically proven RCCs in 29 patients (17 men, 12 women; mean age, 59 years), examinations were performed with a 16-MDCT scanner. The protocol included unenhanced and three-phase (arterial, portal, and nephrographic-excretory) contrast-enhanced CT. The data were analyzed by two reviewers blinded to the histopathologic results. Any discrepancy was resolved by consensus. The presence of a regular, high- or low-attenuation halo surrounding a renal neoplasm was considered to represent renal pseudocapsule. The accuracy of MDCT in the detection of pseudocapsule with the histopathologic results as the standard of reference was evaluated. Unenhanced transverse images and multiplanar reformations in the transverse, coronal, and sagittal planes of each contrast-enhanced phase were separately analyzed. The chi-square two-way test was used to compare each CT phase and multiplanar reformation with histologic results.

RESULTS

The mean diameter of RCCs on CT scans was 5.6 cm (range, 2.8-15 cm), in accordance with the pathologic result. MDCT enabled detection of renal pseudocapsule in 20 of 29 RCCs with 83% sensitivity, 80% specificity, 95% positive predictive value, 50% negative predictive value, and 83% overall accuracy. Imaging in the portal and nephrographic phases with coronal and sagittal reformations proved more accurate in the detection of pseudocapsule (p < 0.05).

CONCLUSION

Multiphase MDCT with multiplanar reformations had satisfactory results in the detection of renal pseudocapsule in RCC.

Single minimum incision endoscopic radical nephrectomy for renal tumors with preoperative virtual navigation using 3D-CT volume-rendering

Background

Single minimum incision endoscopic surgery (MIES) involves the use of a flexible high-definition laparoscope to facilitate open surgery. We reviewed our method of radical nephrectomy for renal tumors, which is single MIES combined with preoperative virtual surgery employing three-dimensional CT images reconstructed by the volume rendering method (3D-CT images) in order to safely and appropriately approach the renal hilar vessels. We also assessed the usefulness of 3D-CT images.

Methods

Radical nephrectomy was done by single MIES via the translumbar approach in 80 consecutive patients. We performed the initial 20 MIES nephrectomies without preoperative 3D-CT images and the subsequent 60 MIES nephrectomies with preoperative 3D-CT images for evaluation of the renal hilar vessels and the relation of each tumor to the surrounding structures. On the basis of the 3D information, preoperative virtual surgery was performed with a computer.

Results

Single MIES nephrectomy was successful in all patients. In the 60 patients who underwent 3D-CT, the number of renal arteries and veins corresponded exactly with the preoperative 3D-CT data (100% sensitivity and 100% specificity). These 60 nephrectomies were completed with a shorter operating time and smaller blood loss than the initial 20 nephrectomies.

Conclusions

Single MIES radical nephrectomy combined with 3D-CT and virtual surgery achieved a shorter operating time and less blood loss, possibly due to safer and easier handling of the renal hilar vessels.

Trends in oncological CT imaging: clinical application of multidetector-row CT and 3D-CT imaging

Computed tomography (CT) plays an essential role in oncological imaging as the modality of screening for malignancies, mapping out the treatment strategy at staging, assessing response to the treatment, and following up patient outcome after the treatment. The advent of multidetector-row CT (MDCT) has brought about dramatic changes in clinical oncological imaging. The very superior temporal and spatial resolution of MDCT has transformed CT imaging from a transaxial cross-sectional technique into an isotropic volume-imaging technique. MDCT facilitates multiphasic contrast-enhanced study for a wide range of body scanning in a single examination, as well as providing flexibility of multidirectional reconstruction and high-quality three-dimensional imaging. With increases in the number of detector rows year by year, systems with 64-detector rows have become commercially available in 2006. The purpose of this article is to review the status of CT imaging in oncological imaging: (1) to outline the impact of MDCT, focusing on oncological imaging and (2) to review the clinical applications of oncological CT imaging with MDCT.

Multislice computed tomography in planning nephron-sparing surgery in a prospective study with 76 patients: comparison of radiological and histopathological findings in the infiltration of renal structures

OBJECTIVE

The aim of this prospective study is to determine the diagnostic accuracy of multidetector-row computed tomography (CT) compared to histopathologic findings in tumor staging of renal cell carcinoma, with the focus on tumor stage, vein and artery infiltration, and infiltration of the renal pelvis.

MATERIALS AND METHODS

In a prospective study, a total of 76 consecutive patients with suspected renal cell carcinoma were preoperatively assessed for tumor staging using multidetector-row CT. Triphasic CT imaging (i.e., noncontrast, arterial, and parenchymal phase) was performed using multidetector-row CT with reconstructed slice thicknesses of 2 and 5 mm. Two blinded readers evaluated the CT scans independently; the results were then correlated with the histopathologic results.

RESULTS

A total of 56 renal cell carcinomas were proven on histopathology. Readers 1 and 2 reached a sensitivity of 1.0 and 1.0 and a specificity of 0.41 and 0.42 for arterial infiltration, a sensitivity of 1.0 and 0.86 and a specificity of 0.58 and 0.5 for venous infiltration, and a sensitivity of 0.75 and 1.0 and a specificity of 0.5 and 0.44 for infiltration of the renal pelvis. The correlation between both readers was 0.7 for all modalities.

CONCLUSIONS

The multiplanar reconstruction capability of multidetector-row CT allowed good sensitivity in predicting arterial infiltration. The lowest specificity was reached in excluding infiltration of the renal pelvis. Despite its high temporal and spatial resolution, the capacity of multidetector CT to predict intrarenal infiltrations is still limited.