Assessment of the kidney tumor vascular supply by two-phase MDCT-angiography

https://doi.org/10.1016/j.ejrad.2007.01.033Get rights and content

Abstract

Purpose

Current kidney surgery uses less invasive laparoscopic and nephron-sparring procedures. Thus, perfect imaging of the renal vasculature is essential for surgery planning. The aim of our retrospective study was to evaluate the accuracy of 16-detector-row CT-angiography in assessing the vascular anatomy of the kidney with a tumor.

Subjects and methods

Referred for computed tomography (CT) because of a suspected renal tumor, 50 consecutive patients (mean age 58.6 years; range 43–82) were enrolled into our retrospective study. All examinations were performed with 16 × 0.75 mm collimation after the intravenous application of 80 ml of a non-ionic contrast material. The imaging protocol contained two-phase scanning in the arterial and then in the venous phase. The vascular anatomy of the kidney with tumor was evaluated using volume rendered (VRT) and maximum intensity images (MIP). Findings were compared with the anatomy found during surgery.

Results

Forty-seven patients underwent nephrectomy, with an advanced clinical stage (IV) found in the three remaining ones. Correct topography of the renal hilus, including a number of arteries and veins, and the anatomy of their branching, was described in 46 patients. A very small upper polar artery was overlooked in one patient. The accuracy for the only-arterial was 97.9% and only-venous anatomy was 100%. The parasitic vasculature of the tumor was discovered in 10 cases and all of them were confirmed by surgery (100% accuracy). Macroscopic intravenous spread of the tumor was discovered in two cases, but microscopic intravenous invasion was confirmed during histology of the kidney specimens in another two cases, the overall tumor staging accuracy reaching 95.7%.

Conclusion

Two-phase multidetector CT is a valuable tool for assessing vascular supply of the kidney before surgery due to the tumor and can fully replace catheter-based angiography.

Introduction

Malignant tumors of the kidneys account for only 1–2% of all malignancies. More than 90% of kidney malignancies are renal cell carcinoma (RCC), while urothelial carcinoma accounts for less than 10%. The incidence of RCC in the population reaches up to 20 new registered tumors per 100,000 population, the number increases slowly according to the incidental detection. Males are predominantly affected, with the male/female ratio ranging between 2:1 and 3:1. Three main subtypes of RCC have been identified: (1) conventional, clear cell, renal carcinoma (CRCC), (2) papillary renal cell carcinoma (PRCC), and (3) chromophobic renal cell carcinoma. The majority of RCC's are CRCC's (over 75%); about 15% are PRCC's, with about 5% being chromophobic RCC's [1], [2]. Current advanced surgical techniques, such as laparoscopic or retroperitoneoscopic nephrectomy and nephron-sparring resection are less invasive surgical procedures used in the treatment of renal tumors [3], [4]. Exact renal tumor staging is critical, as primary surgical resectability is the main condition of successful treatment [5], [6], [7]. Exact assessment of the vasculature of the kidney is essential for surgery planning [8]. Not only the number, site of origin and branching of the renal vessels but, also, the presence of neoplastic vascular invasion or parasitic vessels of the tumor have to be evaluated. The CT-angiography might be used instead obsolete dynamic conventional CT [9] (Fig. 1, Fig. 2, Fig. 3).

Computed tomography angiography (CTA) is well established as a non-invasive technique for imaging of the renal arteries and other visceral abdominal arteries [8], [9], [10], [11], [12], [13], [14], [15]. However, whereas the main renal arteries can be reliably displayed, imaging of the aberrant arteries and branching of the main arteries is not so frequently used as that of the stem arteries [16]. Similarly, two-phase computed tomography is well established in the evaluation of primary and secondary tumors of the liver [17], [18], two-phase examination in the arterial and venous phases is reported relatively rare in the kidneys [19], [20], [21]. Recent studies performed with the use of the multidetector-row CT (MDCT) yielded very high sensitivities and specificities in detecting renal artery stenoses or assessment of the transplant-donor kidney vasculature [12], [22], [23]. The vascular supply of the kidney with tumor can be more complicated due to the enlargement of the capsular or other aberrant vessels. Thus, reliable detection of the complete vascular supply remains a challenge for non-invasive imaging. The aims of the present study were to evaluate the accuracy of two-phase renal CTA in assessing the renal vascular topography and renal tumor staging as compared with surgical and pathological findings.

Section snippets

Subjects and methods

A total of 50 consecutive patients (mean age 58.6 years; range 43–82; 27 males, 23 females) referred for computed tomography due to a suspected tumor were enrolled in a prospective study. All patients were included in this study based only, on the ultrasound finding; no CT examination was done in the past. General informed consent with CTA examination was obtained by the referring physician.

All patients underwent two-phase CTA using a 16-detector-row scanner (Somatom Sensation 16, Siemens,

Results

The revealed advanced malignancy (unresectable tumor or multiple metastases—clinical stage IV) required that three patients be treated using only palliative therapy, nephrectomy was not performed. The remaining 47 patients underwent unilateral surgery within 1 week after CT-angiography and all their tumors were found resectable, procedures review showed in Table 1. A malignant renal tumor was confirmed in 44 cases, benign tumors in 3 cases (Table 2). Correct description and display of the renal

Discussion

Computed tomography angiography (CTA) is a valuable, minimally invasive imaging tool for the visualization and evaluation of the abdominal vessels [10], [11], [12], [14], [24]. Faster scanning ameliorates the contrast bolus exploitation and therefore decreases the overlaying opacification of the veins and arteries [18], [24]. Therefore, it seems to be advantageous to divide data acquisition into two phases, an arterial and a renal-venous one [18]. The high craniocaudal resolution makes it

Acknowledgement

Supported by the research project MSM 0021620819 of the Czech Government.

References (25)

  • P.L. Choyke et al.

    Renal cell carcinoma staging. American College of Radiology. ACR Appropriateness Criteria

    Radiology

    (2000)
  • J. Rydberg et al.

    Evaluation of prospective living renal donors for laparoscopic nephrectomy with multisection CT: the marriage of minimally invasive imaging with minimally invasive surgery

    Radiographics

    (2001)
  • Cited by (18)

    • Application of combined computed tomography arteriography, venography, and urography in laparoscopic partial nephrectomy with segmental artery clamping

      2014, Urology
      Citation Excerpt :

      The vasculature characteristics of the tumors were evaluated using volume-rendered and maximum-intensity imaging techniques.5,6 VRT displays provide images with excellent visualization of tumors and their topographic relationship with adjacent anatomic structures.6,7 Access and clamping strategies for target arteries were determined on the basis of the 3D models by the radiologist and surgeon preoperatively.

    • Quality improvement guidelines for diagnostic arteriography

      2014, Journal of Vascular and Interventional Radiology
      Citation Excerpt :

      Multidetector CT angiography can play a role in assessing aneurysms and thrombi associated with vasculitides, although conventional arteriography may better delineate microaneurysms (49). Multidetector CT angiography can reliably diagnose renal artery neoplasms, define their blood supply, as well as depict extrarenal extension of tumor (50,51). CT evaluation of the renal arteries has long been a replacement for CA in the pre- and postoperative evaluation for renal transplantation (52).

    • Three-dimensional renal CT angiography for guiding segmental renal artery clamping during laparoscopic partial nephrectomy

      2013, Clinical Radiology
      Citation Excerpt :

      Firstly, an image-fusion technique was used to create a combined display of the renal parenchyma (MPR) with the renal artery tree (VR). Conventional 3D VR images cannot display the interrelationship between the tumour and the adjacent segmental arteries due to opaque kidney images.21,22 This image-fusion technique made it possible to simultaneously visualize the intrarenal arterial tree, kidney parenchyma, tumour, and its supplying arteries in exquisite detail.

    View all citing articles on Scopus
    View full text