www.rcr.ac.uk Recommendations for cross-sectional imaging in cancer management, Second edition Renal and adrenal tumours Faculty of Clinical Radiology www.rcr.ac.uk Contents Who should be imaged? 5 Renal cell carcinoma 3 Staging objectives 5 Clinical background 3 Staging 5 Who should be imaged? 3 Follow-up 5 Staging objectives 3 Tip 5 Staging 3 Follow-up 4 Evaluation of the incidental adrenal gland mass Tips 4 in patients with cancer 6 Staging objectives 6 Adrenocortical cancer 5 Clinical background 5 References 7 3 www.rcr.ac.uk Renal cell carcinoma Clinical background determine the upper level of the extent of the thrombus in relation to the hepatic veins. Renal cell carcinoma occurs in 16 out of 100,000 . To identify tumours in the contralateral kidney. individuals, with a true increase in its incidence in 1 recent decades. It accounts for 80–90% of In small tumours, additional objectives include primary malignancies of the kidney in adults and assessing the feasibility of nephron-sparing the majority are clear cell carcinoma. Less surgery and therefore includes: common variants are papillary and chromophobe-type carcinomas which are less An evaluation of the relationship of the tumour aggressive. Accurate assessment of venous . to the collecting system of the kidney and the invasion is essential for planning surgery as, if kidney’s arterial and venous supply present, the upper extent of tumour thrombus Providing optimal images to aid local surgical within the inferior vena cava (IVC) is vital . information. Metastases are a strong indicator of removal; for example, multiplanar reformats a poor prognosis, and common sites include the for laparoscopic removal of small tumours. lungs, bones and adrenal glands. The para-aortic and paracaval nodes are the regional lymph Staging nodes, and spread to these or beyond the CT perirenal fascia markedly reduces patients’ CT of the abdomen and chest is the investigation survival. Over recent years, nephron-sparing of choice to stage the primary tumour and to surgery has been increasingly used for tumours detect metastatic disease; the pelvis only needs less than 4 cm as this preserves renal function. to be included if there are symptoms referable to Minimally invasive techniques including this, such as bone pain. laparoscopic surgery and percutaneous ablation are further treatment options. Pre-contrast scans through the abdomen, in Who should be imaged? order to study contrast medium enhancement features for optimal characterisation of All patients in whom renal cell carcinoma is lesions. This is not required for staging renal suspected on imaging techniques should be tumours. imaged using CT. MRI is usually reserved for 100–150 ml of intravenous iodinated contrast . patients unable to undergo CT or to address medium injected at 3–4 ml/sec. 2 particular questions regarding venous invasion. MDCT with acquisition in the cortico- . medullary phase at 30 seconds performed Staging objectives through the abdomen only. (This is of particular importance if considering nephron- To assess the size of the tumour. sparing surgery in order to optimally visualise To assess perinephric tumour invasion. the arterial anatomy.) . To identify local and regional lymph node For lesion characterisation (prior to definitive . involvement. diagnosis), post-contrast MDCT should be To detect spread into adjacent structures performed at 80–100 seconds to provide a . including the liver, spleen and muscles. true nephrographic phase of enhancement. To identify involvement of the ipsilateral and . Delayed urographic phase images at 8–10 . contralateral adrenal glands. minutes are useful to outlining the pelvi- calyceal system especially in patients being To identify the presence and extent of venous . considered for nephron-sparing surgery. invasion including the ipsilateral renal vein and inferior vena cava. Where caval extension is present, it is important to 4 www.rcr.ac.uk Protocol for imaging renal tumours Sequence Plane Slice thickness Field of view Principle observations T1W Axial 6 ± 2 mm Large Primary tumour Venous invasion Lymph node involvement T2W± Axial 6 ± 2 mm Large T1W + fat Axial 6 ± 2 mm Large sat T1W + fat Axial 6 ± 2 mm Large sat (+C) T1W Sagittal/coronal 6 ± 2 mm Large Inferior vena cava and renal vein invasion ±Respiratory triggering Using MDCT, slice thickness will depend on masked. Furthermore, primary renal cell . 18 scanner capability. In general, sections are carcinoma displays wide-ranging uptake of FDG 18 acquired at 1.25–2.5 mm and reformatted at 5 from negative through to intense. FDG PET-CT mm for viewing. is of limited value in evaluating metastatic disease as up to 30% of metastases are not Values of CTDIvol should normally be below the FDG-avid. It may be useful in individual patients relevant national reference dose for the region of in difficult management situations or when 3 scan and patient group (see Appendix and standard imaging is inconclusive. section on Radiation protection for the patient in CT in Section 2). Follow-up MRI The frequency of follow-up depends on stage and MRI is used to solve problems; for example, to histology at presentation at surgery. In principle, assess the extent of venal caval invasion. larger tumours with lymph node infiltration or venous tumour extension are reviewed more Abdominal surface coil (torso) should be used frequently. Data suggest that no follow-up is whenever possible. Optional sequences include needed for T1 N0 M0 tumours. T2 and T3 T1W with electrocardiographic (ECG) gating if tumours not receiving adjuvant therapy are supradiaphragmatic extension is suspected. scanned at 24 and 60 months or when Gradient-echo (GRE) T1W ± C as an option to fat symptomatic. Patients with T3a tumours are sat T1 (above) to assess venous patency. rescanned at three to six months following surgery, as a baseline for future follow-up. Suggested renal vein/caval protocol (additional). CT is the optimal technique. Only post-contrast 3D fat-saturated GRE sequence. scans to include chest and abdomen are required, unless there is a specific indication to At the onset of examination (0 seconds), 0.1 include the pelvis. mmol/kg patient body weight gadolinium- containing contrast medium mixed with 20 ml Tips saline injected at 4 ml/sec with 20 seconds data acquisition at 20, 50 and 80 seconds post- Following nephrectomy, unopacified loops of . injection. small bowel lying in the renal resection bed can cause confusion and bowel opacification PET-CT is advised. 18FDG PET-CT is not commonly used for primary As 30% of recurrent disease occurs in the renal tumour assessment as 18FDG is excreted in . chest, follow-up should always include the urine and therefore uptake by tumour may be imaging of the chest. 5 www.rcr.ac.uk Adrenocortical cancer Clinical background Unenhanced scan through the abdomen. 100–150 ml of intravenous iodinated contrast Adrenocortical carcinomas (ACC) are rare and . medium injected at 3–4 ml/sec. only account for 0.05–0.2% of all cancers,4 have MDCT from lung apices to iliac crest at 65 a bimodal age distribution (before the age of five . and in the 4–5th decades), and are more often seconds. ‘functioning’ in children, where the majority Reformatting images in sagittal and coronal . present with virilisation (40%) or in combination planes allows optimal assessment of with Cushing’s syndrome (50%).4 Prognosis is infiltration of adjacent viscera and aids very poor; even in those undergoing complete surgical planning. 4 resection, 85% will recur. Using MDCT, slice thickness will depend on . scanner capability. In general, sections are Who should be imaged? acquired at 1.25–2.5 mm and reformatted at 5 mm for viewing. All patients with a histologically diagnosed adrenocortical carcinoma should be staged. Values of CTDIvol should normally be below the relevant national reference dose for the region of Patients presenting with adrenal hyper function scan and patient group (see Appendix and especially virilisation or Cushing’s syndrome. section on Radiation protection for the patient in CT in Section 2). Staging objectives Follow-up To determine the size of the ACC. To detect invasion of retroperitoneal fat CT of the abdomen as a baseline following . around the adrenal and adjacent viscera. surgery and if relapse is suspected. To identify venous invasion. Tip . To identify lymph node enlargement. To identify distant metastases. MDCT-reformatted images provide a useful Staging vascular map prior to surgical resection. CT CT is the technique of choice. The abdomen and chest should be examined. 6 www.rcr.ac.uk Evaluation of the incidental adrenal gland mass in patients with cancer Staging objectives AI – AD x 100 AI – AU To distinguish between adrenal adenomas and non-adenomatous masses in patients with cancer where CT AD = attenuation value at 15 min Adrenals AU = attenuation of unenhanced image Pre-contrast scan. Attenuation value <0 HU . AI = attenuation value at 1 min has 100% specificity for adenoma and <10 HU has a specificity of 98% for adenomas. A value of greater than 60% is 98% specific Homogeneous mass <10 HU requires no for an adrenal adenoma. further characterisation. Mass >10 HU requires CT washout or MRI as below. MRI Adrenals CT washout Gradient echo T2W sequence to characterise Intravenous injection of 100 ml contrast . adrenal mass – cystic v solid. medium at 3–4 ml/sec. Dual-echo chemical shift imaging (CSI). Acquisition through the adrenals at 1 minute . Calculate signal intensity loss by evaluating and 15 minutes. the Signal Intensity Index (SII). Using MDCT, slice thickness will depend on . scanner capability. In general, sections are SI (in-phase) – SI (out-of-phase) x 100 acquired at 1.25–2.5 mm and reformatted at 5 SI (in-phase) mm for viewing. Values of CTDI should normally be below A value exceeding SI (in-phase) >11.2% is .