1818FF--FDG PET for Mediastinal Staging FDG PET for Mediastinal Staging

of Lungof Lung CCancerancer::

Which SUV Threshold Makes SenseWhich SUV Threshold Makes Sense??

Dirk HellwigDirk Hellwig et al. et al.

Department of Nuclear MedicineDepartment of Nuclear Medicine,, Saarland University Medical CenterSaarland University Medical Center,,HomburgHomburg//SaarSaar,, GermanyGermany

J Nucl Med J Nucl Med 2007;2007; 48:176148:1761––17661766

Resident: Apichaya Claimon, M.D.

Advisor: Pongpija Tuchinda, M.D.

EEvaluation of mediastinal valuation of mediastinal LNLN involvementinvolvement

�� Mediastinoscopy Mediastinoscopy && ExcisionExcision

�� GGold standardold standard

�� SenSen 80%, Spec 100%80%, Spec 100%

�� InvasiveInvasive

�� ContrastContrast--enhanced CT & MRIenhanced CT & MRI

�� UUse size criteria se size criteria

�� to differentiate between benign to differentiate between benign && malignantmalignant

�� But 21% of metastases are in normal sized LNBut 21% of metastases are in normal sized LN

�� 40%40% of enlarged of enlarged LNLN are are no malignancyno malignancy

��1818FF--FDG PETFDG PET

�� TThe most accurate noninvasive modality for he most accurate noninvasive modality for

staging mediastinal staging mediastinal LNLN in lung cancerin lung cancer

Aim of the studyAim of the study

�� To determine optimum SUV threshold To determine optimum SUV threshold

�� for for mediastinalmediastinal LN staging in patients with LN staging in patients with

NSCLC NSCLC

�� To compare diagnostic performance of To compare diagnostic performance of

SUV analysisSUV analysis with with visual interpretationvisual interpretation

MATERIALS AND METHODSMATERIALS AND METHODS

�� Retrospective studyRetrospective study

�� PPatients with suspected atients with suspected NSCLCNSCLC

1818FF--FDG PET FDG PET

within 6 wkwithin 6 wk

MediastinoscopyMediastinoscopy

�� Total 95 Total 95 (75 men, 20 woman, age 62(75 men, 20 woman, age 62++9)9)

1818FF--FDG PET LN evaluationFDG PET LN evaluation

�� Visual Visual

�� Compare with Compare with mediastinalmediastinal blood poolblood pool

�� 6 level (6 level (-- -- -- to + + +)to + + +)

�� SUV maxSUV max

�� 1.5 cm ROI 1.5 cm ROI

�� over visible LN over visible LN oror typical area of LN stationtypical area of LN station

RESULTRESULT

Total 95

Lung CA 80

(SCC 39, adeno 31,

unspecified NSCLC 4,

Carcinosarcoma 1,

SCLC 5)

Malig mesothelioma 2

Malig lymphoma 1

MFH 1

Benign 11

(TB 4,

after pneumonia 2,

silicosis 2,

sarcoidosis 1)

23/80 patient

mediastinal LN metastasis

(29%)

70/311 nodes

Positive

(23%)

Total 371 nodes biopsy

1818FF--FDG PET in LN staging of lung cancerFDG PET in LN staging of lung cancer

�� unaffected lymph nodes unaffected lymph nodes ((N0N0))

�� peribronchialperibronchial or or hilarhilar lymph node involvement lymph node involvement ((N1N1))

�� ipsilateralipsilateral mediastinalmediastinal and and subcarinalsubcarinal involvement involvement ((N2N2))

�� contralateralcontralateral and and supraclavicularsupraclavicular involvement involvement ((N3N3))

Comparison of SUVComparison of SUVmaxmax in mediastinal in mediastinal LNLN

�� SUVs were higher in metastatic lymph node stations (P < 0.01)SUVs were higher in metastatic lymph node stations (P < 0.01)

�� TumorTumor--free LN with inflammatory changes free LN with inflammatory changes

had SUV = 2.7 + 2.0 had SUV = 2.7 + 2.0

(range, 0.8(range, 0.8––14.9; n = 146)14.9; n = 146)

Diagnostic performanceDiagnostic performance

�� Using Visual InterpretationUsing Visual Interpretation

�� Using SUV Using SUV 2.52.5 as Cutoff Valueas Cutoff Value

Using Visual InterpretationUsing Visual Interpretation

Using Visual InterpretationUsing Visual Interpretation

Using Visual InterpretationUsing Visual Interpretation

Visual Interpretation Visual Interpretation vs.vs. SUV AnalysisSUV Analysis

AUCAUC

�� Visual Visual

0.9300.930++0.0220.022

�� SUV SUV

0.8990.899++0.0250.025

No significantNo significant

(P = 0.241)(P = 0.241)

Determination of Determination of

Optimal SUV ThresholdOptimal SUV Threshold

Minimal FNR + FPR at SUV = 2.5

Highest diagnostic accuracy at SUV= 4.5

CONCLUSIONCONCLUSION

�� Human observationHuman observation has higher sensitivity has higher sensitivity

than than SUV analysisSUV analysis

�� But But SUVSUV has greater value in less has greater value in less

experience observerexperience observer

�� SUV threshold = 2.5 is feasible SUV threshold = 2.5 is feasible

�� For differentiating benign from metastatic For differentiating benign from metastatic

mediastinalmediastinal lymph nodes in lung CA patientslymph nodes in lung CA patients

�� SenSen = 89%, Spec = 84%= 89%, Spec = 84%

�� False False -- : small metastasis: small metastasis

�� False + : LN inflammationFalse + : LN inflammation

�� High NPV (96%) High NPV (96%)

�� if PET if PET ––veve ; can omit ; can omit mediastinoscopymediastinoscopy

�� Highest diagnostic accuracy at SUV Highest diagnostic accuracy at SUV >> 4.54.5

�� But SUV = 2.5 cannot applied to LN But SUV = 2.5 cannot applied to LN

metastasis in other tumor typesmetastasis in other tumor types

�� Because differ Because differ 1818FF--FDG uptakeFDG uptake

Using Visual InterpretationUsing Visual Interpretation