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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.

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Related in: MedlinePlus

Line-block diagram of the imaging protocol used to obtain the planar, SPECT, and SPECT/CT images.
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Figure 1: Line-block diagram of the imaging protocol used to obtain the planar, SPECT, and SPECT/CT images.

Mentions: Patients were kept nil per os for approximately 6 hours and then intravenously administered 925 MBq (25 mCi) of 99mTc-MIBI. Immediately after radiotracer injection, 30 dynamic 1-minute planar frames were acquired with a 64 × 64 pixel matrix size using a Siemens Symbia 16-slice SPECT/CT (Erlangen, Germany) system with low-energy high-resolution collimators. This dynamic phase was then followed by a 28-minute SPECT/CT acquisition. SPECT imaging was acquired initially in step and shoot mode at 28 seconds per step with 60 steps. Detector range was set to 180 degrees per detector. CT images were acquired at 130 kV and 90 mA with dose care modulation enabled. The 3-mm axial images were reconstructed for both SPECT and CT data sets. The first patient demonstrated high renal parenchymal background uptake after directly starting SPECT/CT acquisition post planar imaging. As such, it was postulated that a delayed SPECT acquisition would potentially be of value. Hence, an additional 17-minute SPECT was acquired immediately after the first SPECT (step and shoot mode at 17 seconds per step with 60 steps and 180 degree detector range), and the relative tumor-to-background ratio appeared to visually improve. For the sake of consistency and visual diagnostic accuracy, all future patients underwent 30 minutes of planar dynamic imaging directly after injection followed by a 17-minute SPECT/CT at 75 minutes after injection (Fig. 1). The length of the 45-minute delay between the dynamic and SPECT acquisitions was chosen as a compromise between maximizing tumor-to-background ratio and still maintaining a reasonable workflow and overall study time.


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)

Line-block diagram of the imaging protocol used to obtain the planar, SPECT, and SPECT/CT images.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 1: Line-block diagram of the imaging protocol used to obtain the planar, SPECT, and SPECT/CT images.
Mentions: Patients were kept nil per os for approximately 6 hours and then intravenously administered 925 MBq (25 mCi) of 99mTc-MIBI. Immediately after radiotracer injection, 30 dynamic 1-minute planar frames were acquired with a 64 × 64 pixel matrix size using a Siemens Symbia 16-slice SPECT/CT (Erlangen, Germany) system with low-energy high-resolution collimators. This dynamic phase was then followed by a 28-minute SPECT/CT acquisition. SPECT imaging was acquired initially in step and shoot mode at 28 seconds per step with 60 steps. Detector range was set to 180 degrees per detector. CT images were acquired at 130 kV and 90 mA with dose care modulation enabled. The 3-mm axial images were reconstructed for both SPECT and CT data sets. The first patient demonstrated high renal parenchymal background uptake after directly starting SPECT/CT acquisition post planar imaging. As such, it was postulated that a delayed SPECT acquisition would potentially be of value. Hence, an additional 17-minute SPECT was acquired immediately after the first SPECT (step and shoot mode at 17 seconds per step with 60 steps and 180 degree detector range), and the relative tumor-to-background ratio appeared to visually improve. For the sake of consistency and visual diagnostic accuracy, all future patients underwent 30 minutes of planar dynamic imaging directly after injection followed by a 17-minute SPECT/CT at 75 minutes after injection (Fig. 1). The length of the 45-minute delay between the dynamic and SPECT acquisitions was chosen as a compromise between maximizing tumor-to-background ratio and still maintaining a reasonable workflow and overall study time.

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