Materials and Methods definition

Materials and Methods. The requirement for institutional review board approval was waived. Intra- and interpatient variation of PZ ADCs was determined by means of repeated measurements of normal ADCs at three magnetic resonance (MR) examina- tions in a retrospective cohort of 10 consecutive patients who had high prostate-specific antigen levels and negative findings at transrectal ultrasonographically-guided biopsy. In these patients, no signs of PZ cancer were found at all three MR imaging sessions. The effect of interpatient variation on the assessment of prostate cancer aggressive- ness was examined in a second retrospective cohort of 51 patients with PZ prostate cancer. Whole-mount step- section pathologic evaluation served as reference standard for placement of regions of interest on tumors and normal PZ. Repeated-measures analysis of variance was used to determine the significance of the interpatient variations in ADCs. Linear logistic regression was used to assess whether incorporating normal PZ ADCs improves the pre- diction of cancer aggressiveness.

Materials and Methods. The study had ethics committee approval, and a nested case-control design was used and included 55 patients with lung cancer detected at computed tomography (CT) and confirmed with histologic examination and a sample of 72 of 4873 control subjects without nodules at CT. All patients underwent direct-detector digital chest radiogra- phy in two projections within 2 months of the screening CT. Four radiologists with varying experience identified and localized potential cancers on chest radiographs by using a confidence scale of level 1 (no lesion) to 5 (defi- nite lesion). Localization receiver operating characteristic (ROC) analysis was performed. On the basis of the as- sumption that suspicious lesions seen at chest radiogra- phy would lead to further work-up with CT, the number of work-up CT examinations per detected cancer (CT exami- nations per cancer) was calculated at various confidence levels for the screening population (cancer rate in study population, 1.3%). Results: Tumor size ranged from 6.8 to 50.7 mm (median, 11.8 mm). Areas under the localization ROC curve ranged from 0.52 to 0.69. Detection rates substantially varied with the observers’ experience and confidence level: At a confidence level of 5, detection rates ranged from 18% at one CT examination per cancer to 53% at 13 CT exami- nations per cancer. At a confidence level of 2 or higher, detection rates ranged from 94% at 62 CT examinations per cancer to 78% at 44 CT examinations per cancer.

Materials and Methods. SSNs on all baseline computed tomographic (CT) scans from the National Lung Cancer Trial that would have been classified as Lung-RADS category 3 or higher were iden- tified, resulting in 374 SSNs for analysis. An experienced screening radiologist volumetrically segmented all solid cores and located all malignant SSNs visible on baseline scans. Six experienced chest radiologists independently determined which nodules to upgrade to category 4X, a recently introduced category for lesions that demonstrate additional features or imaging findings that increase the suspicion of malignancy. Malignancy rates of purely size- based categories and category 4X were compared. Fur- thermore, the false-positive rates of category 4X lesions were calculated and observer variability was assessed by using Fleiss k statistics. Results: The observers upgraded 15%–24% of the SSNs to cate- gory 4X. The malignancy rate for 4X nodules varied from 46% to 57% per observer and was substantially higher than the malignancy rates of categories 3, 4A, and 4B SSNs without observer intervention (9%, 19%, and 23%, respectively). On average, the false-positive rate for cat- egory 4X nodules was 7% for category 3 SSNs, 7% for category 4A SSNs, and 19% for category 4B SSNs. Of the falsely upgraded benign lesions, on average 27% were transient. The agreement among the observers was mod- erate, with an average k value of 0.535 (95% confidence interval: 0.509, 0.561).

Materials and Methods. The institutional review board approved this study and waived the need for informed consent. A retrospective cohort of 70 patients (age range, 48–70 years; median, 62 years), all of whom were scheduled to undergo radi- cal prostatectomy and underwent preoperative 3-T multi- parametric magnetic resonance (MR) imaging, including T2-weighted, diffusion-weighted, and dynamic contrast material–enhanced imaging, were included. The digi- tized prostatectomy slides were annotated for cancer and noncancerous disease and coregistered to MR imaging with an interactive deformable coregistration scheme. Computer-identified features for each of the noncancer- ous disease categories (eg, benign prostatic hyperplasia [BPH], prostatic intraepithelial neoplasia [PIN], inflam- mation, and atrophy) and prostate cancer were extracted. Feature selection was performed to identify the features with the highest discriminatory power. The performance of these five features was evaluated by using the area un- der the receiver operating characteristic curve (AUC). Results: High-b-value diffusion-weighted images were more discrim- inative in distinguishing BPH from prostate cancer than apparent diffusion coefficient, which was most suitable for distinguishing PIN from prostate cancer. The focal appear- ance of lesions on dynamic contrast-enhanced images may help discriminate atrophy and inflammation from cancer. Which imaging features are discriminative for different be- nign lesions is influenced by cancer grade. The apparent diffusion coefficient appeared to be the most discriminative feature in identifying high-grade cancer. Classification re- sults showed increased performance by taking into account specific benign types (AUC = 0.70) compared with grouping all noncancerous findings together (AUC = 0.62).

Materials and Methods. As part of the ethics-committee approved Dutch-Belgian Randomised Lung Cancer Multi-Slice Screening Trial (▇▇▇▇▇▇), computed tomography (CT) was used to screen 2994 current or former heavy smokers, aged 50– 74 years, for lung cancer. CT was repeated after 1 and 3 years, with additional follow-up CT scans if necessary. All baseline CT scans were screened for nodules. Nodule vol- ume was determined with automated volumetric analysis. Homogeneous solid nodules, attached to a fissure with a lentiform or triangular shape, were classified as PFNs. Nodules were considered benign if they did not grow dur- ing the total follow-up period or were proved to be benign in a follow-up by a pulmonologist. Prevalence, growth, and malignancy rate of PFNs were assessed. Results: At baseline screening, 4026 nodules were detected in 1729 participants, and 19.7% (794 of 4026) of the nod- ules were classified as PFNs. The mean size of the PFNs was 4.4 mm (range: 2.8–10.6 mm) and the mean volume was 43 mm3 (range: 13–405 mm3). None of the PFNs were found to be malignant during follow-up. Between baseline and the first follow-up CT scan, 15.5% (123 of 794) were found to have grown, and 8.3% (66 of 794) had a volume doubling time of less than 400 days. One PFN was resected and proved to be a lymph node. Conclusion: PFNs are frequently found at CT scans for lung cancer. They can show growth rates in the range of malignant nodules, but none of the PFNs in the present study turned out to be malignant. Recognition of PFNs can reduce the number of follow-up examinations required for the workup of suspicious nodules. q RSNA, 2012 of Malignancy1

Materials and Methods. The institutional review board waived the need for in- formed consent. Retrospectively, 34 patients were included who had prostate cancer and had undergone multiparamet- ric MR imaging, including T2-weighted, diffusion-weighted, and dynamic contrast material–enhanced MR imaging prior to radical prostatectomy. Six radiologists less experienced in prostate imaging and four radiologists experienced in prostate imaging were asked to characterize different regions suspicious for cancer as benign or malignant on multiparametric MR images first without and subsequently with CAD software. The effect of CAD was analyzed by using a multiple-reader, multicase, receiver operating char- acteristic analysis and a linear mixed-model analysis.

Materials and Methods. The study design was approved by the Institutional Review Board of the ▇▇▇▇▇ ▇ ▇▇▇▇▇ Hospital. According to Span- ish law, for this type of study, no informed consent was necessary. Five radiologists from three hospitals twice in- terpreted lumbar MR examination results in 53 patients with low back pain, with at least a 14-day interval between assessments. Radiologists were unaware of the clinical and demographic characteristics of the patients and of their colleagues’ assessments. At the second assessment, they were unaware of the results of the first assessment. Reports on ▇▇▇▇▇ changes, osteophytes, Schmorl nodes, diffuse defects, disk degeneration, annular tears (high- signal-intensity zones), disk contour, spondylolisthesis, and spinal stenosis were collected by using the Spanish version of the Nordic ▇▇▇▇▇ Consensus Group classifica- tion. The k statistic was used to assess intra- and inter- observer agreement for findings with a prevalence of 10% or greater and 90% or lower. k was categorized as almost perfect (0.81–1.00), substantial (0.61–0.80), moderate (0.41–0.60), fair (0.21–0.40), slight (0.00–0.20), or poor (,0.00).

Materials and Methods. In this ethics committee–approved study, 46 individuals with 49 computed tomographically (CT)-detected and his- tologically proved lung cancers and 65 patients without nodules at CT were retrospectively included. All subjects participated in a lung cancer screening trial. Chest radio- graphs were obtained within 2 months after screening CT. Four radiology residents and two experienced radiologists were asked to identify and localize potential cancers on the chest radiographs, first without and subsequently with the use of CAD software. A figure of merit was calculated by using free-response receiver operating characteristic analysis. Results: Tumor diameter ranged from 5.1 to 50.7 mm (median, 11.8 mm). Fifty-one percent (22 of 49) of lesions were subtle and detected by two or fewer readers. Stand-alone CAD sensitivity was 61%, with an average of 2.4 false- positive annotations per chest radiograph. Average sen- sitivity was 63% for radiologists at 0.23 false-positive annotations per chest radiograph and 49% for residents at 0.45 false-positive annotations per chest radiograph. Figure of merit did not change significantly for any of the observers after using CAD. CAD marked between five and 16 cancers that were initially missed by the readers. These correctly CAD-depicted lesions were rejected by radiolo- gists in 92% of cases and by residents in 77% of cases.

Materials and Methods. A consecutive sample of 141 adolescent and parent/caregiver pairs was selected. Adolescents answered the short version of the Child Perceptions Questionnaire (CPQ11–14), while parents answered the Parental-Caregiver Perceptions Questionnaire (P-CPQ). The CPQ11–14 and the P-CPQ have 14 items in common that are organized through four subscales: oral symptoms (OS), functional limitations (FL), emotional well-being (EW), and social well-being (SW). Agreement on the overall score and agreement on the subscales were determined using comparison and correlation analysis. The comparison analysis was carried out by comparing the mean directional and absolute differences, and the correlation analysis was performed using the intraclass correlation coefficient (ICC). Results: A total of 135 pairs of adolescents and parents/caregivers agreed to answer the questionnaires, providing a response rate of 95.7%. The mean age of the adolescents was