TIRADS SCORING : its Efficacy and Accuracy
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Transcript of TIRADS SCORING : its Efficacy and Accuracy
IS TIRADS A PRACTICAL AND ACCURATE
SYSTEM FOR USE IN DAILY CLINICAL PRACTICE?
Presented by Dr Roshan Valentine
PG Resident
St Johns Medical College Bangalore
AUTHORS:Anuradha Chandramohan, Abhishek Khurana, B T Pushpa, Marie Therese Manipadam1, DukhabandhuNaik2,Nihal Thomas2, Deepak Abraham3, MazhuvancharyJacob Paul3, CMC Vellore
INTRODUCTION
• 12% of adult Asian population have a palpable nodule
• 80% among children in iodine-deficient parts of India.
• Incidence of thyroid cancer is low.
• Ultrasound is a widely accepted imaging modality for the initial assessment
• Thyroid Imaging Reporting and Data System (TIRADS) described by Kwak et al.[15] is a relatively simple system which can be easily adopted
OBJECTIVE
To assess
• Positive predictive value
• Inter-observer variability of TIRADS
MATERIALS AND METHODS
STUDY POPULATION• IERB Review
• Dept of radiology at CMC vellore
• Jan 2012 – nov 2012
• Estimated sample size for assessing inter-reader reliability – 250
• 346 nodules of 307 pts
INCLUSION CRITERIA• Solitary nodule and nodules in MNG > 1cm
• FNAC – benign/malignant lesion
• Undergone Surgery -FNAC yielded suspicious for malignancy, indeterminate or inadequate sampling
MATERIALS AND METHODS
THYROID ULTRASOUND• ACUSON S2000 AND ACUSON ANTARES Siemens
• 7-11Mhz probe
• 2 radiologists with 8 years experience
• Reviewed by a 3rd radiologist (3 yrs experience)
• Features assessed for :
1)Composition: solid cystic mixed
2)Echogenicity
3)margins: well defined +/- halo sigin , microlobulated , ill-defined , irregular
4)Calcification :micro/macro
5) Shape : round/t>w or oval
MATERIALS AND METHODS
THYROID ULTRASOUND
Features suggesting malignancy :• Hypoechoic or markedly hypoechoic
• Irregular/spiculated
• Microlobulated
• Ill defined/fuzzy margins
• Microcalcifications
• Round shape
MATERIALS AND METHODS
TIRADS CATEGORISATION
• Cat 2: completely cystic , comet tail artefacts or spongiform
• Cat 3: Solid, oval, well-defined, isoechoic nodules
• Cat 4 a, b and c
THYROID FNAC
• FNAC b/w 12h to 2 days post USG
• By Surgeon and radiologist
• 2-3 aspirations by 23g needle attached to 5cc syringe
• Cytology technician to confirm the adequacy of the specimen
• BETHESDA system by cytopathologists for classification• Class I: inadequate
• Class II : benign
• Class III: atypical or follicular cells of indeterminate significance
• Class IV: follicular neoplasm
• Class V: suspicious for malignancy
• Class VI : Malignant
THYROID FNAC
TIRADS≤3 + non diag
FN/HPE+notplanned for Sx
Follow for 1 year with USG every 6mnth
No change in nodule
BENIGN
STATISTICAL ANALYSIS
• SPSS analytics 16.0 software
• Receiver operating characteristic (ROC) curve for TIRADS efficacy
• Inter-rater reliability was measured using the quadratic weighted kappa statistics,
RESULTS
• Total of 272 nodules : 154 benign ; 118 malignant
• Malignancy : M>F
• Among malignant nodules , males were older than females
RESULTS
RESULTS
RESULTS
Diagnostic performance of TIRADS on considering
Sn(%) Sp(%) PPV(%) NPV(%) Accuracy(%)
Benign: 2&3Malignant : 4a,4b,4c & 5
72 68.8 63.9 76.2 70.2
Benign 2,3 & 4aMalignant : 4b,4c & 5
60.2 85.1 75.5 73.6 74.2
RESULTS
INTER-OBSERVER AGREEMENT• Overall substantial agreement for assigning TIRADS category
• poor agreement for assigning TIRADS categories 4a and 4b
DISCUSSION
• Several classification system to stratify thyroid malignancy
Risk – complex
• The classification by Kwak et al is simple and similar to BIRADS and familiar to most radiologists – hence used
• Study by Kim et al reported the USG suspicious features malignancy
DISCUSSION
DISCUSSION
• PPV and specificity improved when TIRADs4a → 3.
• Thus its better to follow up 4a Pts than subjecting them to surgery
LIMITATIONS
• No prior training for examiners
• Referral centre – hence most of the lesions included were malignant(selection bias)
• 34/112 malignant nodules were follicular variant of papillary cancers – benign appearance.• TB thyroid – rare and can mimic malignancy
• False positive and false negative of cytology results
• USG – guided FNAC in only 30% , rest were blind FNAC by surgeons
CONCLUSION
• PPV for malignancy was high for TIRADS category 5 and 4c nodules
• Reassigning TIRADS 4a →3 will improve PPV and specificity.
• Overall agreement between observers for assigning TIRADS category was substantial
• Thus, TIRADS is a simple and practical method of assessing thyroid nodules and can be used in practice.
TIRADS
TIRADS 1 - normal thyroid gland
TIRADS 2 - benign lesions
TIRADS 3 - probably benign lesions
TIRADS 4 - suspicious lesions (subclassified as 4a, 4b and 4c with increasing risk of malignancy)
TIRADS 5 - probably malignant lesions (more than 80% risk of malignancy)
TIRADS 6 - biopsy proven malignancy