CT and angiographic correlates: surgical image of renal mass lesions

Peripheral vascular lesions in adults referred to MRI/MRA: Multivariable analysis of imaging features to help differentiate benign vascular anomalies from malignancies

PURPOSE

Symptomatic peripheral vascular lesions in adults are often clinically diagnosed as benign vascular anomalies and may receive MRI/MRA for pre-treatment vascular mapping. Malignant neoplasms are difficult to distinguish from benign vascular anomalies on MRI/MRA. This study was performed to determine if there are imaging signs that can distinguish malignancies from benign vascular anomalies in adults imaged with MRI/MRA.

MATERIALS AND METHODS

A radiology database was retrospectively searched for ISSVA classification terms in MRI/MRA reports from 1/1/2002-1/1/2019. Adult patients (n = 50, 52 corresponding lesions) with contrast-enhanced MRI/MRA, peripheral soft tissue based lesion (s), and available pathology or long-term (>1 year) imaging follow-up were included. MRI/MRA images were reviewed by 3 readers for the following lesional characteristics: morphology (marginal lobulation, internal septations, distinct soft tissue mass), peri-articular location, T2-weighted characteristics (hyperintensity, heterogeneity, perilesional edema, and adjacent triangular T2-peaks), bulk fat, hemorrhage, enhancement pattern (peripheral, diffuse, or absent), neovascularity, low-flow venous malformation type enhancement, arterial enhancement within 6 s, enhancement curve (progressive, plateau, or washout), measured size, and multifocality. The MRI/MRA features' associated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. To identify factors predictive of malignancy, a two-stage multivariable analysis was performed.

RESULTS

23% (12/52) of the lesions, corresponding to 22% (11/50) of the patients, were malignant neoplasms. No single imaging feature reliably predicted malignancy (PPV ≤ 60%). Absence of distinct soft tissue mass excluded malignancy (NPV 100%). Multivariate analysis derived a summary score based on the five strongest predictors of malignancy: adjacent T2 peaks, age ≥ 70 years, distinct soft tissue mass, lesion size ≥ 5 cm, and absence of septations. A score ≥ 3 resulted in sensitivity of 92% and specificity of 85%.

CONCLUSION

Extremity MRI/MRA rarely differentiates malignant from benign soft-tissue vascular tumors in adults. However, MRI/MRA can suggest malignancy when patient age and multiple imaging features are considered. Periodic clinical follow-up after the planned endovascular or operative procedure should be performed to avoid missing a malignancy.

Comparison of excretory urography, angiography, ultrasound and computed tomography for T category staging of renal cell carcinoma

The diagnostic significance of excretory urography, renal angiography, ultrasound and computed tomography for predicting the stage of tumours was evaluated by comparing their results with peroperative and histopathological findings. Thirty-nine out of 178 patients operated on for renal cell carcinoma from 1981 to 1988 were subjected to all four diagnostic procedures. The T stage was determined correctly by computed tomography in 80% of the cases, by ultrasound in 74.5%, by renal angiography in 64% and by excretory urography in 56.5%. Excretory urography did not give any significant additional information on the T category compared with the other imaging methods. Angiography is still of value in that it gives preoperative information on the collateral circulation and the number of renal arteries and their location.

A comparison of radiologic methods in the diagnosis of renal mass lesions

The reliability of radiologic diagnosis was studied in 99 patients undergoing ultrasonography, computerized tomography and angiography in work up of renal mass lesions. The diagnoses were confirmed by angiography combined with percutaneous puncture or by surgery. Of the lesions, 37 were simple renal cysts and 56 were renal cell carcinomas. Eighty-eight percent were diagnosed correctly by ultrasonography, 96% by computerized tomography and 84% by angiography. The conclusion is that the radiologic evaluation of a renal mass lesion found at urography should start with ultrasonography. Percutaneous puncture is not recommended if all criteria of a simple renal cyst are strictly fulfilled at ultrasonography. In all other cases a computerized tomography is thought to be mandatory to avoid false negative diagnoses of malignant tumours or other diseases which may need therapy. In some patients a combination with angiography and percutaneous puncture is advised to establish a diagnosis prior to surgery.

Surgical approach to inferior vena caval extension of renal carcinoma

Between 1979 and 1985, 10 patients were treated for renal carcinoma with extension into the inferior vena cava but without evidence of disseminated disease. Two of these had tumour thrombus extension up to the level of the hepatic veins and in four the extension was above the level of the diaphragm, two of which entered the atrium. Thrombus was removed en bloc at radical nephrectomy. Six patients are still alive, with a mean survival of 22 months. There was no correlation between the level of tumour thrombus and perinephric extension or indeed any correlation between tumour thrombus level and overall survival. It is suggested that tumour thrombus in the inferior vena cava, in the absence of metastatic disease, should be managed by radical surgery.

Comparative value of ultrasonography, computerized tomography, angiography and excretory urography in the staging of renal cell carcinoma

From 1982 to 1985, 225 patients with renal cell carcinoma were treated by nephrectomy. To evaluate the diagnostic significance of ultrasonography in predicting tumor stage the results of ultrasonography, computerized tomography, renal angiography and excretory urography were compared to the histopathological findings. Since local tumor extension has a considerable impact on the operation strategy evaluation of the T classification was of particular interest. All 4 diagnostic procedures were performed in 73 of the 225 patients. The T stage was determined correctly by ultrasonography in 77.8 per cent of the patients, while the tumor was not identifiable in only 0.6 per cent. Computerized tomography was almost as reliable as ultrasonography (the T stage was predicted correctly in 72.3 per cent of the examinations). In contrast, the tumor was staged correctly by angiography in only 57.2 per cent of the patients and by excretory urography in only 59.2 per cent. From these results ultrasonography appears to be an effective, noninvasive, inexpensive and safe procedure to evaluate the T stage of renal tumors.

Staging of genitourinary cancers. The role of diagnostic imaging

Computed tomography (CT) is currently the standard modality for staging of urologic cancer in most institutions. It is used for demonstrating nodal involvement, and for demonstrating invasion of the primary lesion into surrounding fat, muscle, or other tissues or organs. It is also useful for demonstrating hepatic metastases in renal and vesical carcinomas. The problem with computed tomography, however, is that it can only show whether the nodes are large or not; neither can it show the nodal architecture, nor can it detect metastases in normal-sized nodes. Intravesical sonography has been helpful for staging papillary bladder cancer. Transrectal sonography has been somewhat helpful for demonstrating seminal vesicle invasion in patients with prostatic carcinoma. Inferior vena cavography and renal venography can be helpful for demonstrating whether a renal, renal pelvic, or adrenal carcinoma has extended into either vein. Lymphography can show nodal architecture and metastases in normal-sized nodes, and can make possible needle biopsy of abnormal-appearing nodes even if they are normal sized. The examination cannot show very small or microscopic nodal metastases, and it can miss abnormal nodes totally if they have been completely replaced by metastases. It yields false positives when fatty or fibrous infiltration of the nodes has occurred. It is used primarily for staging patients with testis or prostatic carcinoma. Bone scans are essential for staging prostatic carcinoma. Magnetic resonance imaging (MRI) is helpful in some cases of renal cell carcinoma. Multiplanar imaging prevents overstaging. It is also accurate for showing whether the renal vein or inferior vena cava are involved. Enlarged lymph nodes are easily distinguished from vessels. For staging bladder carcinoma involving the fundus or base of the bladder, MRI is better than CT. Microscopic nodal metastases, such as are common in carcinoma of the prostate, currently are not detected by any imaging modality.

Tailored angiographic approach to small hypovascular renal tumors

The value of an appropriate oblique view renal arteriography which we call "tailored oblique," was illustrated in 2 cases. In the first case, a renal mass on the left side with anterior exophytic growth was found by computerized tomography (CT). In the second case, a tumor on the right side with posterior exophytic growth was detected by CT. Preoperative angiographies were performed. In both cases, the anteroposterior projections were not diagnostic. But in the "tailored oblique" projections both showed definite tumor vessels. Both tumors were resected and proved to be renal cell carcinomas. We believe "tailored oblique" projection provides additional confirmative information on the nature of the tumor.

Tomographic renal cortical scintigraphy: correlation with intravenous urography, computed tomography, ultrasonography, angiography, and nuclear magnetic resonance imaging

This study evaluates single-photon renal tomoscintigraphy (SPECT) in the evaluation of renal masses and correlates this modality, where indicated, with computed tomography (CT), ultrasonography (US), angiography (ANGIO) and nuclear magnetic resonance imaging (NMR). Eight patients with renal cortical lesions detected on intravenous urography (IVP) were evaluated by SPECT and planar nuclear imaging using Tc-99m glucoheptonate (GH). Three of these patients were felt particularly likely to have renal tumors and were additionally evaluated with US, CT, ANGIO and NMR. The five patients with nodules on IVP that were not particularly suggestive of malignancy had functioning, benign, renal tissue accounting for their IVP lesions. Four of five were found by planar-GH nuclear imaging, five/five by SPECT-GH. In addition, SPECT-GH allowed better "confidence" in the normal renal tissue diagnosis in three/five cases. Of the three renal lesions that were highly suggestive of malignancy, two were hypernephromas and one was hypertrophied functioning cortical tissue. All three were correctly identified prospectively on SPECT-GH; however, one hypernephroma was missed on planar-GH. NMR, CT, and ANGIO detected only one of two hypernephromas prospectively (US detected both); all four modalities incorrectly diagnosed the hypertrophied tissue suggestive of malignancy.

Computed tomography of renal oncocytomas

A retrospective analysis of 5 renal oncocytomas studied with CT was performed. Oncocytomas appeared as rounded hypodense solid masses with sharp margination from the normal renal parenchyma. They showed uniform homogeneous enhancement on CT scans performed after drip infusion of urographic contrast. One oncocytoma studied with dynamic CT scanning demonstrated a stellate (spoke-wheel) pattern of enhancement. No evidence of involvement of adjacent renal parenchyma, perinephric fat, renal veins or regional lymph nodes was present at CT and the findings were confirmed at surgery. Although the differential diagnosis between renal oncocytoma and hypernephroma may not be possible, preoperative awareness of a potentially benign lesion may guide the surgeon to attempt renal preserving surgery instead of the customary nephrectomy.

Peroperative staging of renal carcinoma. A methodologic comparison

Angiography, computed tomography and ultrasonography were compared with respect to staging of renal carcinoma in 41 patients with 46 renal tumours. Angiography and ultrasonography gave correct staging in 52% and 48%, respectively, while correct staging was achieved with computed tomography in 80% of the tumours.

Comparison of dynamic and conventional computed tomography, angiography, and ultrasonography in the staging of renal cell carcinoma

A prospective study was carried out on 22 patients to assess the diagnostic ability to stage renal cell carcinoma by computed tomography, dynamic computed tomography, arteriography, ultrasonography, and radionuclide scanning. Dynamic computed tomography remedied the most consequential diagnostic shortcomings of conventional computed tomography and proved the most sensitive, specific, and accurate technique for staging of all types of contiguous extension of renal cell carcinoma. For the identification of bone metastases, radionuclide scintiscanograms were found most accurate and cost-effective.

Comparison of computerized tomography and excretory urography in detection and evaluation of renal masses

The ability of excretory urography and computerized tomography to detect renal masses was compared in 120 consecutive cases. Computerized tomography consistently provided more information than excretory urography, usually was able to distinguish renal tumors from cysts and provided additional useful information regarding staging of renal neoplasms and the presence of unsuspected associated pathological conditions.

Oncologic imaging: kidney and ureter

Malignant cancers of the kidney and ureter account for only 2-3% of all neoplasms in man. However, early diagnosis and treatment can have a profound effect on patient prognosis and survival. This article seeks to amalgamate a large body of information related to the pathology or primary renal tumors and metastatic disease with current imaging strategies to assist the clinician and enhance his understanding of the wide variety of modern imaging techniques available. Current tumor staging classifications are presented and the various imaging strategies are keyed to detection, definition and treatment options for tumors of the renal parenchyma and ureter. The strengths and limitations of all available imaging modalities are reviewed. An optimal approach to the imaging work up is developed with regard to availability, evolving technology and most importantly, cost efficacy. The controversies and conflicts in imaging and treatment options are explored while constructing a step by step approach that will be both flexible and utilitarian for the clinician faced with daily oncologic management choices.