18F- FDG PET/CT in the Diagnosis of Tumor Thrombosis

T Davidson1, E Konen2 , O Goitein2, A Avigdor3, S T Zwas1 , E Goshen1

Departments of Nuclear Medicine1,Radiology2 and Hemato-Oncology3

Sheba Medical Center, Tel Aviv University, Israel

Background

Venous Thrombo-Embolism (VTE):• well-recognized • relatively frequent • complication of malignancy

Tumor Thrombosis:• a rare complication in this condition

Largest series described six

cases of Tumor Thrombosis diagnosed by PET with simultaneous CT

Lai P, et al.

Detection of tumour thrombus by 18F-FDG-PET/CT

imaging.

Eur J Cancer Prev. 2007 Feb;16(1):90-4.

Background

• The role of PET/CT in the diagnosis

of Tumor Thrombosis • The Differential diagnosis of

Tumor Thrombosis from Venous Thrombo-Embolism

Aims

Materials and Methods

• Retrospective study of PET/CT scans

• 10 patients with suspected intravascular

thrombosis on either PET/CT or contrast enhanced CT scans

• 6 M, 4 F; Age 31-76 (mean 53.5 y)

Materials and Methods

• In 8/10 pts the intravascular lesion was

an incidental finding on PET-CT scan during investigation of patients with known malignancy

• 2/10 pts were referred to PET-CT for

further evaluation of a known intravascular lesion diagnosed on CT /MRI

Materials and Methods

Criteria for a positive PET :

• Increased focal or linear uptake of

18F-FDG in the involved vessel• Standard uptake value (SUV)

above 2.5

Materials and Methods

• Findings were categorized: PET positive (+) or PET negative

(-)

• Compared to contrast enhanced CT ultrasound doppler, pathology when available, clinical follow-up

• 7/10 patients showed PET(+) with Tumor Thrombosis

• The other 3 patients ( with intraluminal vascular

lesions on contrast-enhanced CT ) had negative PET(-) and Tumor

Thrombosis was ruled out

Results

of the 7 positive PET

6 had intra-luminal vascular defects

on contrast-enhanced CT consistent

with thrombosis.

1 had a positive US-Doppler

Results

Tumor Thrombosis in SMV54y M with pancreatic

carcinoma

Tumor Thrombosis in SMV54y M with pancreatic

carcinoma

Tumor Thrombosis in IVC 46y M with RCC

Results

3/10 patients with intraluminal vascular

lesions on contrast-enhanced CT had a

negative PET in 2 patients blood clot was to be confirmed

and 1 had intravenous leiomyomatosis

Blood clot in SMV64y M with NHL

Intravenous leiomyomatosisin IVC , 49y F

Intravenous leiomyomatosisin IVC , 49y F

Results

PET/CT correctly differentiated

between Tumor Thrombosis and benign Venous Thrombosis in all our patients

Results

Underlying pathology in 7 patients with Tumor Thrombosis

4 lymphoma 1 pancreatic ca 1 renal cell ca 1 head - neck squamous cell ca

Involved Vessel with Tumor Thrombosis

1 Jugular vein

1 Subclavian vein 2 SVC

1 SMV 1 Iliac vein 1 IVC

Potential Pitfalls

False positive PET findings

may be due to • inflammatory lesions ,

including infected catheters

in the venous vasculature

Potential Pitfalls

In contrast, missed diagnoses may relate:• to the size of the lesion, • the avidity of the underlying pathological process to FDG

Conclusion

Contrast-enhanced CT defines extent of thrombotic lesions, while PET contributes the functional information of these lesions