Limits...
Bone Windows for Distinguishing Malignant from Benign Primary Bone Tumors on FDG PET/CT.

Costelloe CM, Chuang HH, Chasen BA, Pan T, Fox PS, Bassett RL, Madewell JE - J Cancer (2013)

Bottom Line: Results.CT-BW demonstrated higher specificity than PET-only and PET/CT-BW (p=0.0005 and p=0.0103, respectively) and trended toward higher sensitivity than CT-STW (p=0.0759).Conclusion.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Diagnostic Radiology.

ABSTRACT
Objective. The default window setting on PET/CT workstations is soft tissue. This study investigates whether bone windowing and hybrid FDG PET/CT can help differentiate between malignant and benign primary bone tumors. Materials and methods. A database review included 98 patients with malignant (n=64) or benign primary bone (n=34) tumors. The reference standard was biopsy for malignancies and biopsy or >1 year imaging follow-up of benign tumors. Three radiologists and/or nuclear medicine physicians blinded to diagnosis and other imaging viewed the lesions on CT with bone windows (CT-BW) without and then with PET (PET/CT-BW), and separate PET-only images for malignancy or benignity. Three weeks later the tumors were viewed on CT with soft tissue windows (CT-STW) without and then with PET (PET/CT-STW). Results. Mean sensitivity and specificity for identifying malignancies included: CT-BW: 96%, 90%; CT-STW: 90%, 90%; PET/CT-BW: 95%, 85%, PET/CT-STW: 95%, 86% and PET-only: 96%, 75%, respectively. CT-BW demonstrated higher specificity than PET-only and PET/CT-BW (p=0.0005 and p=0.0103, respectively) and trended toward higher sensitivity than CT-STW (p=0.0759). Malignant primary bone tumors were more avid than benign lesions overall (p<0.0001) but the avidity of benign aggressive lesions (giant cell tumors and Langerhans Cell Histiocytosis) trended higher than the malignancies (p=0.08). Conclusion. Bone windows provided high specificity for distinguishing between malignant and benign primary bone tumors and are recommended when viewing FDG PET/CT.

No MeSH data available.


Related in: MedlinePlus

Tumor of the anterior and medial walls of the right maxilla in an 83-year-old woman. (A) CT-STW shows a dense tumor that appears well defined and smoothly lobulated. (B) FDG avidity demonstrated by the fused PET/CT-STW dataset raises the suspicion of malignancy (SUVmax 5.6). (C) While a greater degree of bone detail becomes apparent on the hybrid PET/CT-BW dataset, the tumor itself remains largely obscured by the extent of the high FDG uptake. Unlike the mildly FDG-avid Ewing sarcoma in Fig. 4D, the high avidity of most malignancies is likely to obscure the fine detail otherwise demonstrated by the bone windows. This may be the reason why no statistically significant relationships were found with the fused PET/CT-BW dataset. (D) Osteolysis is most readily apparent on CT-BW (arrow). Ill-defined margins are also now identified (arrowheads), further supporting the diagnosis of malignancy. The tumor contains a combination of centrally dense and peripherally “fluffy” mineralized osteoid matrix. Biopsy indicated osteosarcoma.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3753526&req=5

Figure 3: Tumor of the anterior and medial walls of the right maxilla in an 83-year-old woman. (A) CT-STW shows a dense tumor that appears well defined and smoothly lobulated. (B) FDG avidity demonstrated by the fused PET/CT-STW dataset raises the suspicion of malignancy (SUVmax 5.6). (C) While a greater degree of bone detail becomes apparent on the hybrid PET/CT-BW dataset, the tumor itself remains largely obscured by the extent of the high FDG uptake. Unlike the mildly FDG-avid Ewing sarcoma in Fig. 4D, the high avidity of most malignancies is likely to obscure the fine detail otherwise demonstrated by the bone windows. This may be the reason why no statistically significant relationships were found with the fused PET/CT-BW dataset. (D) Osteolysis is most readily apparent on CT-BW (arrow). Ill-defined margins are also now identified (arrowheads), further supporting the diagnosis of malignancy. The tumor contains a combination of centrally dense and peripherally “fluffy” mineralized osteoid matrix. Biopsy indicated osteosarcoma.

Mentions: Specificity for the detection of primary bone tumors was significantly high with CT-BW when compared to PET/CT-BW (p=0.0103). This suggests that the fine bony detail that is visible with CT-BW is useful for distinguishing benign from malignant lesions, and that this bony detail may be obscured by FDG uptake. Specificity was also higher with CT-BW than with PET-only (p=0.0005), indicating that the anatomic data provided by the bone windows was more useful for identifying the lesions than FDG-uptake alone (Fig. 2). Sensitivity for detecting malignancy trended higher with CT-BW than CT-STW (p=0.0759, Fig 3 A and D). The margins of primary bone tumors are an important indicator of their biological potential 24-25. Malignancies are more likely to produce a greater degree of osteolysis than benign lesions 24-25. Soft tissue windows may over-emphasize tumor margins and spuriously make cortical or trabecular bone appear intact. Bone windows can reveal the osteolysis that is obscured by the soft tissue window setting (Fig. 4).


Bone Windows for Distinguishing Malignant from Benign Primary Bone Tumors on FDG PET/CT.

Costelloe CM, Chuang HH, Chasen BA, Pan T, Fox PS, Bassett RL, Madewell JE - J Cancer (2013)

Tumor of the anterior and medial walls of the right maxilla in an 83-year-old woman. (A) CT-STW shows a dense tumor that appears well defined and smoothly lobulated. (B) FDG avidity demonstrated by the fused PET/CT-STW dataset raises the suspicion of malignancy (SUVmax 5.6). (C) While a greater degree of bone detail becomes apparent on the hybrid PET/CT-BW dataset, the tumor itself remains largely obscured by the extent of the high FDG uptake. Unlike the mildly FDG-avid Ewing sarcoma in Fig. 4D, the high avidity of most malignancies is likely to obscure the fine detail otherwise demonstrated by the bone windows. This may be the reason why no statistically significant relationships were found with the fused PET/CT-BW dataset. (D) Osteolysis is most readily apparent on CT-BW (arrow). Ill-defined margins are also now identified (arrowheads), further supporting the diagnosis of malignancy. The tumor contains a combination of centrally dense and peripherally “fluffy” mineralized osteoid matrix. Biopsy indicated osteosarcoma.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3753526&req=5

Figure 3: Tumor of the anterior and medial walls of the right maxilla in an 83-year-old woman. (A) CT-STW shows a dense tumor that appears well defined and smoothly lobulated. (B) FDG avidity demonstrated by the fused PET/CT-STW dataset raises the suspicion of malignancy (SUVmax 5.6). (C) While a greater degree of bone detail becomes apparent on the hybrid PET/CT-BW dataset, the tumor itself remains largely obscured by the extent of the high FDG uptake. Unlike the mildly FDG-avid Ewing sarcoma in Fig. 4D, the high avidity of most malignancies is likely to obscure the fine detail otherwise demonstrated by the bone windows. This may be the reason why no statistically significant relationships were found with the fused PET/CT-BW dataset. (D) Osteolysis is most readily apparent on CT-BW (arrow). Ill-defined margins are also now identified (arrowheads), further supporting the diagnosis of malignancy. The tumor contains a combination of centrally dense and peripherally “fluffy” mineralized osteoid matrix. Biopsy indicated osteosarcoma.
Mentions: Specificity for the detection of primary bone tumors was significantly high with CT-BW when compared to PET/CT-BW (p=0.0103). This suggests that the fine bony detail that is visible with CT-BW is useful for distinguishing benign from malignant lesions, and that this bony detail may be obscured by FDG uptake. Specificity was also higher with CT-BW than with PET-only (p=0.0005), indicating that the anatomic data provided by the bone windows was more useful for identifying the lesions than FDG-uptake alone (Fig. 2). Sensitivity for detecting malignancy trended higher with CT-BW than CT-STW (p=0.0759, Fig 3 A and D). The margins of primary bone tumors are an important indicator of their biological potential 24-25. Malignancies are more likely to produce a greater degree of osteolysis than benign lesions 24-25. Soft tissue windows may over-emphasize tumor margins and spuriously make cortical or trabecular bone appear intact. Bone windows can reveal the osteolysis that is obscured by the soft tissue window setting (Fig. 4).

Bottom Line: Results.CT-BW demonstrated higher specificity than PET-only and PET/CT-BW (p=0.0005 and p=0.0103, respectively) and trended toward higher sensitivity than CT-STW (p=0.0759).Conclusion.

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Diagnostic Radiology.

ABSTRACT
Objective. The default window setting on PET/CT workstations is soft tissue. This study investigates whether bone windowing and hybrid FDG PET/CT can help differentiate between malignant and benign primary bone tumors. Materials and methods. A database review included 98 patients with malignant (n=64) or benign primary bone (n=34) tumors. The reference standard was biopsy for malignancies and biopsy or >1 year imaging follow-up of benign tumors. Three radiologists and/or nuclear medicine physicians blinded to diagnosis and other imaging viewed the lesions on CT with bone windows (CT-BW) without and then with PET (PET/CT-BW), and separate PET-only images for malignancy or benignity. Three weeks later the tumors were viewed on CT with soft tissue windows (CT-STW) without and then with PET (PET/CT-STW). Results. Mean sensitivity and specificity for identifying malignancies included: CT-BW: 96%, 90%; CT-STW: 90%, 90%; PET/CT-BW: 95%, 85%, PET/CT-STW: 95%, 86% and PET-only: 96%, 75%, respectively. CT-BW demonstrated higher specificity than PET-only and PET/CT-BW (p=0.0005 and p=0.0103, respectively) and trended toward higher sensitivity than CT-STW (p=0.0759). Malignant primary bone tumors were more avid than benign lesions overall (p<0.0001) but the avidity of benign aggressive lesions (giant cell tumors and Langerhans Cell Histiocytosis) trended higher than the malignancies (p=0.08). Conclusion. Bone windows provided high specificity for distinguishing between malignant and benign primary bone tumors and are recommended when viewing FDG PET/CT.

No MeSH data available.


Related in: MedlinePlus