Perfect Inter-reader Agreement Research Articles

Assessment of Interradiologist Agreement Regarding Mammographic Breast Density Classification Using the Fifth Edition of the BI-RADS Atlas.

The objective of the present study was to assess interradiologist agreement regarding mammographic breast density assessment performed using the rating scale outlined in the fifth edition of the BI-RADS atlas of the American College of Radiology. Breast density assessments of 1000 cases were conducted by five radiologists from the same institution who together had recently undergone retraining in mammographic breast density classification based on the fifth edition of BI-RADS. The readers assigned breast density grades (A-D) on the basis of the BI-RADS classification scheme. Repeat assessment of 100 cases was performed by all readers 1 month after the initial assessment. A weighted kappa was used to calculate intrareader and interreader agreement. Intrareader agreement ranged from a kappa value of 0.86 (95% CI, 0.77-0.93) to 0.89 (95% CI, 0.81-0.95) on a four-category scale (categories A-D) and from 0.89 (95% CI, 0.86-0.92) to 0.94 (95% CI, 0.89-0.97) on a two-category scale (category A-B vs category C-D). Interreader agreement ranged from substantial (κ = 0.76; 95% CI, 0.73-0.78) to almost perfect (κ = 0.87; 95% CI, 0.86-0.89) on a four-category scale, and the overall weighted kappa value was substantial (0.79; 95% CI, 0.78-0.83). Interreader agreement on a two-category scale ranged from a kappa value of 0.85 (95% CI, 0.83-0.86) to 0.91 (95% CI, 0.90-0.92), and the overall weighted kappa was 0.88 (95% CI, 0.87-0.89). Overall, with regard to mammographic breast density classification, radiologists had substantial interreader agreement when a four-category scale was used and almost perfect interreader agreement when a dichotomous scale was used.

How to assess background activity

Many common PET segmentation methods for malignant lesions use surrounding background activity as a reference. To date, background has to be measured by drawing a second volume of interest (VOI) in nearby, undiseased tissue. This is time consuming as two VOIs have to be determined for each lesion. The aim of our study was to analyse whether background activity in different organs and body regions could be calculated from the tumour VOI by histogram analyses. The institutional review board waived informed consent for this retrospective study. For each of the following tumour types and areas - head and neck (neck), lung, hepatic metastasis (liver), melanoma (skin), and cervix (pelvis) - 10 consecutive patients with biopsy-proven tumours who underwent (18)F-fluorodeoxyglucose-PET in January 2012 were retrospectively selected. One lesion was selected and two readers drew a cubical VOI around the lesion (VOItumour) and over the background (VOIBG). The mean value of VOIBG was compared with the mode of the histogram, using equivalence testing with an equivalence margin of ±0.5 SUV. Inter-reader agreement was analysed for the mean background, and the mode of the VOItumour histogram was assessed using the concordance correlation coefficient. For both readers, the mode of VOItumour was equivalent to the mean of VOIBG (P<0.0001 for R1 and R2). The inter-reader agreement was almost perfect, with a concordance correlation coefficient of greater than 0.92 for both the mode of VOItumour and the mean of VOIBG. Background activity determined within a tumour VOI using histogram analysis is equivalent to separately measured mean background values, with an almost perfect inter-reader agreement. This could facilitate PET quantification methods based on background values without increasing workload.

Intra-Individual Comparison of Lymphatic Drainage Patterns Using Subareolar and Peritumoral Isotope Injection for Breast Cancer

Controversy exists in the literature regarding the optimal site for lymphatic mapping in breast cancer. This study was designed to characterize lymphatic drainage patterns within the same patient after subareolar (SA) and peritumoral (PT) radiopharmaceutical injections and examine the impact of reader interpretation on reported drainage. In this prospective trial, 27 women with breast cancer underwent sequential preoperative SA and PT injections of 0.5 to 2.7 mCi of technetium-99 m filtered sulfur colloid 3 days or more apart. Patterns of radiopharmaceutical uptake were reviewed independently by two nuclear medicine physicians. Inter-reader agreement and injection success were assessed in conjunction with observed drainage patterns. There was near perfect inter-reader agreement observed on identification of axillary LN drainage after PT injection (P = 0.0004) and substantial agreement with SA injection (P = 0.0344). SA injection was more likely to drain to only axillary LNs, whereas PT injection appeared more likely to drain to both axillary and extra-axillary LNs, although no statistically significant differences were found. All patients with extra-axillary drainage after PT injection (n = 6 patients) had only axillary drainage after SA injection. Dual drainage was observed for six patients with PT injection and one patient with SA injection. Our findings suggest that radiopharmaceutical injected in the SA location has a high propensity to drain to axillary LNs only. After controlling for patient factors and demonstrating inter-reader agreement, the inability to demonstrate statistically significant differences in drainage based on injection site suggests that lymphatic drainage patterns may be a function of patient and tumor-specific features.

Diagnostic Performance of Multidetector-Row CT for Predicting the Preoperative Staging of Renal Cell Carcinoma

Purpose: We assessed the diagnostic performance of multidetector-row computed tomography (MDCT) for preoperatively predicting the T-staging of renal cell carcinoma (RCC). Materials and Methods: All the MDCT studies were performed using a 16- or 40-slice MDCT scanner and the three-phase CT images, including unenhanced, corticomedullary and delayed nephrographic phase images. For the differentiation between T2 disease and T3 disease, a four-point scale was used and a score of more than three was considered indicative of T3 disease. The imaging findings were compared with the surgical specimens with using the 2002 TNM staging system. Statistical analysis was performed using McNemar’s test, statistics and receiver operating characteristic (ROC) analysis. Results: The 144 RCCs consisted of 72 T1a, 31 T1b, 16 T2, 13 T3a and 12 T3b. For all the T-staging, the accuracies of MDCT were excellent ( 87%) for both readers. For predicting T3 disease on MDCT, the area under the receiver operating characteristics curve (Az) for both readers was 0.898 and 0.896, respectively. The interreader agreement was almost perfect (= 0.853). Conclusion: MDCT was accurate for preoperatively predicting the T-staging of RCCs, with almost perfect interreader agreement.