Limits...
Initial experience using 99mTc-MIBI SPECT/CT for the differentiation of oncocytoma from renal cell carcinoma.

Rowe SP, Gorin MA, Gordetsky J, Ball MW, Pierorazio PM, Higuchi T, Epstein JI, Allaf ME, Javadi MS - Clin Nucl Med (2015)

Bottom Line: As a result, a large number of patients harboring a benign oncocytoma undergo unnecessary surgical resection.Relative quantification was performed by measuring tumor-to-normal renal parenchyma background ratios.In contrast, the 3 RCCs were profoundly photopenic relative to renal background (range of uptake ratios, 0.21-0.31). 99mTc-MIBI SPECT/CT appears to be of value in scintigraphically distinguishing benign renal oncocytoma from RCC.

View Article: PubMed Central - PubMed

Affiliation: From the *The Russell H. Morgan Department of Radiology and Radiological Science, †The James Buchanan Brady Urological Institute and Department of Urology, and ‡Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD; and §Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany.

ABSTRACT

Purpose: The differentiation of oncocytoma from renal cell carcinoma (RCC) remains a challenge with currently available cross-sectional imaging techniques. As a result, a large number of patients harboring a benign oncocytoma undergo unnecessary surgical resection. In this study, we explored the utility of 99mTc-MIBI SPECT/CT for the differentiation of these tumors based on the hypothesis that the large number of mitochondria in oncocytomas would lead to increased 99mTc-MIBI uptake.

Patients and methods: In total, 6 patients (3 with oncocytoma and 3 with RCC) were imaged with 99mTc-MIBI SPECT/CT. Relative quantification was performed by measuring tumor-to-normal renal parenchyma background ratios.

Results: All 3 oncocytomas demonstrated radiotracer uptake near or above the normal renal parenchymal uptake (range of uptake ratios, 0.85-1.78). In contrast, the 3 RCCs were profoundly photopenic relative to renal background (range of uptake ratios, 0.21-0.31).

Conclusions: 99mTc-MIBI SPECT/CT appears to be of value in scintigraphically distinguishing benign renal oncocytoma from RCC.

Show MeSH

Related in: MedlinePlus

A, One-minute postinjection posterior dynamic planar image of patient 1 demonstrating a subtle photopenic defect in the cortex of the upper pole of the right kidney at the site of the patient’s known oncocytoma (arrowhead). The patient was status post-left nephrectomy, hence the lack of visualization of the left kidney. B, Thirty-minute postinjection posterior dynamic planar image of the same patient. There has been fill-in of the large right upper pole oncocytoma (arrowhead) with relative retention of radiotracer in the mass higher than that in the surrounding normal renal parenchyma.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4358706&req=5

Figure 2: A, One-minute postinjection posterior dynamic planar image of patient 1 demonstrating a subtle photopenic defect in the cortex of the upper pole of the right kidney at the site of the patient’s known oncocytoma (arrowhead). The patient was status post-left nephrectomy, hence the lack of visualization of the left kidney. B, Thirty-minute postinjection posterior dynamic planar image of the same patient. There has been fill-in of the large right upper pole oncocytoma (arrowhead) with relative retention of radiotracer in the mass higher than that in the surrounding normal renal parenchyma.

Mentions: The dynamic planar images of the 3 patients with known oncocytomas were qualitatively reviewed. The 2 larger oncocytomas demonstrated relative photopenia in the locations of the tumors on early dynamic images with gradual fill-in to approximately the uptake level of the background renal parenchyma or higher at the end of the dynamic phase (Fig. 2). The smallest oncocytoma imaged (patient 2) was difficult to resolve on the dynamic planar images, emphasizing the importance of the subsequent SPECT acquisition. The planar images for the patients with RCC were also reviewed, and for those masses large enough to resolve on the planar imaging, the early appearance was similar to that for oncocytoma with relative photopenia. However, later fill-in with radiotracer was not visually observed (data not shown). A final observation from the dynamic planar images is that a fraction of the injected 99mTc-MIBI quickly washes through the kidneys and is excreted into the urine, whereas the majority of the radiotracer that reaches the kidneys accumulates in the renal parenchyma and is not washed out. Indeed, at the end of 30 minutes of dynamic images, there was no qualitative evidence of radiotracer within the renal collecting systems. These observations have previously been suggested in work that evaluated the utility of 99mTc-MIBI as a renal functional imaging agent.14


Initial experience using 99mTc-MIBI SPECT/CT for the differentiation of oncocytoma from renal cell carcinoma.

Rowe SP, Gorin MA, Gordetsky J, Ball MW, Pierorazio PM, Higuchi T, Epstein JI, Allaf ME, Javadi MS - Clin Nucl Med (2015)

A, One-minute postinjection posterior dynamic planar image of patient 1 demonstrating a subtle photopenic defect in the cortex of the upper pole of the right kidney at the site of the patient’s known oncocytoma (arrowhead). The patient was status post-left nephrectomy, hence the lack of visualization of the left kidney. B, Thirty-minute postinjection posterior dynamic planar image of the same patient. There has been fill-in of the large right upper pole oncocytoma (arrowhead) with relative retention of radiotracer in the mass higher than that in the surrounding normal renal parenchyma.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4358706&req=5

Figure 2: A, One-minute postinjection posterior dynamic planar image of patient 1 demonstrating a subtle photopenic defect in the cortex of the upper pole of the right kidney at the site of the patient’s known oncocytoma (arrowhead). The patient was status post-left nephrectomy, hence the lack of visualization of the left kidney. B, Thirty-minute postinjection posterior dynamic planar image of the same patient. There has been fill-in of the large right upper pole oncocytoma (arrowhead) with relative retention of radiotracer in the mass higher than that in the surrounding normal renal parenchyma.
Mentions: The dynamic planar images of the 3 patients with known oncocytomas were qualitatively reviewed. The 2 larger oncocytomas demonstrated relative photopenia in the locations of the tumors on early dynamic images with gradual fill-in to approximately the uptake level of the background renal parenchyma or higher at the end of the dynamic phase (Fig. 2). The smallest oncocytoma imaged (patient 2) was difficult to resolve on the dynamic planar images, emphasizing the importance of the subsequent SPECT acquisition. The planar images for the patients with RCC were also reviewed, and for those masses large enough to resolve on the planar imaging, the early appearance was similar to that for oncocytoma with relative photopenia. However, later fill-in with radiotracer was not visually observed (data not shown). A final observation from the dynamic planar images is that a fraction of the injected 99mTc-MIBI quickly washes through the kidneys and is excreted into the urine, whereas the majority of the radiotracer that reaches the kidneys accumulates in the renal parenchyma and is not washed out. Indeed, at the end of 30 minutes of dynamic images, there was no qualitative evidence of radiotracer within the renal collecting systems. These observations have previously been suggested in work that evaluated the utility of 99mTc-MIBI as a renal functional imaging agent.14

Bottom Line: As a result, a large number of patients harboring a benign oncocytoma undergo unnecessary surgical resection.Relative quantification was performed by measuring tumor-to-normal renal parenchyma background ratios.In contrast, the 3 RCCs were profoundly photopenic relative to renal background (range of uptake ratios, 0.21-0.31). 99mTc-MIBI SPECT/CT appears to be of value in scintigraphically distinguishing benign renal oncocytoma from RCC.

View Article: PubMed Central - PubMed

Affiliation: From the *The Russell H. Morgan Department of Radiology and Radiological Science, †The James Buchanan Brady Urological Institute and Department of Urology, and ‡Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD; and §Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany.

ABSTRACT

Purpose: The differentiation of oncocytoma from renal cell carcinoma (RCC) remains a challenge with currently available cross-sectional imaging techniques. As a result, a large number of patients harboring a benign oncocytoma undergo unnecessary surgical resection. In this study, we explored the utility of 99mTc-MIBI SPECT/CT for the differentiation of these tumors based on the hypothesis that the large number of mitochondria in oncocytomas would lead to increased 99mTc-MIBI uptake.

Patients and methods: In total, 6 patients (3 with oncocytoma and 3 with RCC) were imaged with 99mTc-MIBI SPECT/CT. Relative quantification was performed by measuring tumor-to-normal renal parenchyma background ratios.

Results: All 3 oncocytomas demonstrated radiotracer uptake near or above the normal renal parenchymal uptake (range of uptake ratios, 0.85-1.78). In contrast, the 3 RCCs were profoundly photopenic relative to renal background (range of uptake ratios, 0.21-0.31).

Conclusions: 99mTc-MIBI SPECT/CT appears to be of value in scintigraphically distinguishing benign renal oncocytoma from RCC.

Show MeSH
Related in: MedlinePlus