Hani A. Nabi, M.D., Ph.D. Department of Nuclear Medicine School of Medicine and Biomedical Science...

Hani A. Nabi, M.D., Ph.D.Department of Nuclear MedicineSchool of Medicine and Biomedical ScienceUniversity at BuffaloState University of New YorkBuffalo, N.Y. USA

Definition:

Parenchymal lesions, well defined less than 4 cm.Benign Features: Central, concentric or stippled calcifications,

stable for more than 2 years, patients younger than 35 years.

• An SUV of less than 3.5

• SUV: Mean Counts/pixel/sec x calibration factor Injected dose (mCi)/body weight (kg).

Author Patient Size Sens. Spec. (cm)

Dewan, 1993 30 95 80

Gupta, 1993 34 0.6-3.0 95 86

Patz, 1993 51 1.2-6.0 100 89

MultiCenter 237 -- 96 90

•SUV•Tumor to background ratios•SUV versus visual interpretation•SUV: prognostic significance

Hypothesis

FDG uptake, normalized to body weight, overestimates value in heavy patients.

•Mean SUV bw and bsa same = 3.42•SD of SUV bsa smaller•Mean SUV bw varies widely with bw, tending to overestimate low to intermediate FDG uptake in heavy patients and underestimate intermediate--higher FDG uptake in light patients

•107 patients with single pulmonary nodule; 67 malignancies and 27 benign.•SUV bw were compared to visual interpretation by two independent readers.•FDG uptake grade 1-5 (definitely tumor) based on mediastinal uptake (=3).

•SUV and visual analysis nearly identical.•No difference between two readers.•Probability of tumor high (0.93, CI 0.88-1.00) when FDG in tumor exceeded mediastinum.

•EVALUATE SUV’S AND HOW THEY ARE AFFECTED WHEN ROI’S ARE DRAWN IN DIFFERENT PLANES AND IN DIFFERENT AREAS OF THE SAME PLANE•DETERMINE CLINICAL IMPORTANCE OF TUMOR/BKG RATIO OF SUV’S

• SIGNIFICANT VARIATION • (p < 0.009) WAS OBSERVED IN TUMORS

OF ADJACENT PLANE WHERE SUV’S WERE >20

• MINIMAL VARIATION WAS OBSERVED IN SUV’S WHEN ROI’S OF THE TUMOR WERE DRAWN ON ONE PLANE

•UPTAKE TIME•GLUCOSE LEVEL•PARTIAL VOLUME EFFECT•PATIENT SIZE•ROI EFFECT•? NODULE SIZE?

JNM 2002, 43(5): 156, Coronado et al.Compared SUVs amongst nodules < 1.5 cm - > 3.0 cm

45 patients with SPNs SUV > mean

21 SPNs 1.5cm or less ( 2.79)

18 SPNs 1.6-3.0cm (4.88)

7 SPNs 3.0cm or greater (5.16)

32/45 FDG positive

27/30 proven neoplasia

Nodules 1.5cm or less (21)04cm-1.5cm (mean 0.97cm)11 malignant, 4 FN, 10TNFN : 1.0cm , FDG+ but SUVs less 3.5

Nodules 1.5 cm or less had lower SUV’s, a cutoff value of 2.0 might be more appropriate.

Journal of Hematology & Oncology 2008 1:13

Retrospective Study (2 centers)• Criteria for enrollment:

• Positive CT for SPN• Positive FDG PET• Histopathological Biopsy

• 173/420 patients fulfilled above criterion

< 1.0cm 1.1 – 2.0 cm

< 1.0cm 1.1 – 2.0 cm 2.1 – 3.0 cm > 3.0 cm

Average SUV’s Nodules size

2.79 < 1.5 cm

4.88 1.6 – 3.0 cm

5.16 >3.0 cm

SUV max cutoff 2.5 useful in the evaluation of nodules 1cm or greater,has minimal or no value in SPN < 1.0 cm

Hani A. Nabi, M.D., Ph.DL. Li, M.D., Ph.D, John Baker, Ph.DDepartment of Nuclear MedicineSchool of Medicine and Biomedical ScienceUniversity at BuffaloState University of New YorkBuffalo, N.Y. USA

Prognostic significance of FDG PET negative (visual or SUV less than 2.5) SPN.

• Retrospective review of all FDG SPN patients referred by a single pulmonary group from 2000—2004.

• One hundred twenty-eight (128) patients (68 females, 60 males, mean age 63 years, 56% between 51-70 years) fulfilled criteria for negative scans.

• Mean follow-up 29.3 months (8-52 months).

• 72 (56%) were current or former tobacco users.• 8 (6.2%) occupational exposure.• 14 (11%) history of cancer, other than lung.

Nodule Size

<1cm

1-2cm

2.1-3cm

>3cm

59%

20%

8%12%

• 76 patients (59%) had no visual uptake. • 21 had biopsy. • 6 (7.9%) were malignant. • 70/76 (92%) were negative on clinical follow-up of at least 18

months.

0

10

20

30

40

50

60

70

No changed Disappeared Inflammation Granuloma

Number

60

25

95

31.5m

12.3m

Stable

Follow-up

•52 patients (41%) had FDG uptake less than 2.5 • 34 had biopsy.• 23/52 (44%) malignant.• 29/52 were negative for malignancy on follow-up of at least 18

months.

Malignant nodule

2

12

5

3

3

2

2

Carcinoid

Moderated AD CA

Well AD CA

Squamous cell CA

Bronchioalveolar

Metastatic CA

Non-small cell

Nodule types

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

FDG uptake No FDG uptake

% of FDG uptake

Benign

Malignant

55.8%

44.2%

92%

8%

Comparison of benign and malignant nodule number between FDG uptake and no FDG uptake

1.88

1.84

Benign and malignant SUV uptake

Benign Malignant

• The difference in proportion in malignancy between the no-FDG uptake and FDG uptake groups is statistically significant.

• Likelihood ratio Chi-square = 23.6.• P < 0.001.

SPN with no visual FDG uptake have a relatively low likelihood of malignancy (7.9%) compared to lesions with FDG SUV less than 2.5 (44%). This study confirmed our previous work (JNM 2006, 47:173) that there is no predetermined fixed value of SUV cutoff that is accurately able to diagnose malignancy in small pulmonary nodules.