Ali Farooqi

Ordinal Scoring of Coronary Artery Calcifications on Low-Dose CT Scans of the Chest is Predictive of Death from Cardiovascular Disease

PURPOSE To assess the usefulness of ordinal scoring of the visual assessment of coronary artery calcification (CAC) on low-dose computed tomographic (CT) scans of the chest in the prediction of cardiovascular death. MATERIALS AND METHODS All participants consented to low-dose CT screening according to an institutional review board-approved protocol. The amount of CAC was assessed on ungated low-dose CT scans of the chest obtained between June 2000 and December 2005 in a cohort of 8782 smokers aged 40-85 years. The four main coronary arteries were visually scored, and each participant received a CAC score of 0-12. The date and cause of death was obtained by using the National Death Index. Follow-up time (median, 72.3 months; range, 0.3-91.9 months) was calculated as the time between CT and death, loss to follow-up, or December 31, 2007, whichever came first. Logistic regression analysis was used to determine the risk of mortality according to CAC category adjusted for age, pack-years of cigarette smoking, and sex. The same analysis to determine the hazard ratio for survival from cardiac death was performed by using Cox regression analysis. RESULTS The rate of cardiovascular deaths increased with an increasing CAC score and was 1.2% (43 of 3573 subjects) for a score of 0, 1.8% (66 of 3569 subjects) for a score of 1-3, 5.0% (51 of 1015 subjects) for a score of 4-6, and 5.3% (33 of 625 subjects) for a score of 7-12. With use of subjects with a CAC score of 0 as the reference group, a CAC score of at least 4 was a significant predictor of cardiovascular death (odds ratio [OR], 4.7; 95% confidence interval: 3.3, 6.8; P < .0001); when adjusted for sex, age, and pack-years of smoking, the CAC score remained significant (OR, 2.1; 95% confidence interval: 1.4, 3.1; P = .0002). CONCLUSION Visual assessment of CAC on low-dose CT scans provides clinically relevant quantitative information as to cardiovascular death.

Lung Cancers Diagnosed at Annual CT Screening: Volume Doubling Times

PURPOSE To empirically address the distribution of the volume doubling time (VDT) of lung cancers diagnosed in repeat annual rounds of computed tomographic (CT) screening in the International Early Lung Cancer Action Program (I-ELCAP), first and foremost with respect to rates of tumor growth but also in terms of cell types. MATERIALS AND METHODS All CT screenings in I-ELCAP from 1993 to 2009 were performed according to HIPAA-compliant protocols approved by the institutional review boards of the collaborating institutions. All instances of first diagnosis of primary lung cancer after a negative screening result 7-18 months earlier were identified, with symptom-prompted diagnoses included. Lesion diameter was calculated by using the measured length and width of each cancer at the time when the nodule was first identified for further work-up and at the time of the most recent prior screening, 7-18 months earlier. The length and width were measured a second time for each cancer, and the geometric mean of the two calculated diameters was used to calculate the VDT. The χ(2) statistic was used to compare the VDT distributions. RESULTS The median VDT for 111 cancers was 98 days (interquartile range, 108). For 56 (50%) cancers it was less than 100 days, and for three (3%) cancers it was more than 400 days. Adenocarcinoma was the most frequent cell type (50%), followed by squamous cell carcinoma (19%), small cell carcinoma (19%), and others (12%). Lung cancers manifesting as subsolid nodules had significantly longer VDTs than those manifesting as solid nodules (P < .0001). CONCLUSION Lung cancers diagnosed in annual repeat rounds of CT screening, as manifest by the VDT and cell-type distributions, are similar to those diagnosed in the absence of screening.

Emphysema Scores Predict Death From COPD and Lung Cancer

OBJECTIVE Our objective was to assess the usefulness of emphysema scores in predicting death from COPD and lung cancer. METHODS Emphysema was assessed with low-dose CT scans performed on 9,047 men and women for whom age and smoking history were documented. Each scan was scored according to the presence of emphysema as follows: none, mild, moderate, or marked. Follow-up time was calculated from time of CT scan to time of death or December 31, 2007, whichever came first. Cox regression analysis was used to calculate the hazard ratio (HR) of emphysema as a predictor of death. RESULTS Median age was 65 years, 4,433 (49%) were men, and 4,133 (46%) were currently smoking or had quit within 5 years. Emphysema was identified in 2,637 (29%) and was a significant predictor of death from COPD (HR, 9.3; 95% CI, 4.3-20.2; P < .0001) and from lung cancer (HR, 1.7; 95% CI, 1.1-2.5; P = .013), even when adjusted for age and smoking history. CONCLUSIONS Visual assessment of emphysema on CT scan is a significant predictor of death from COPD and lung cancer.

Lung Cancer Associated With Cystic Airspaces

OBJECTIVE The objectives of this study were to determine the frequency of lung cancers associated with a discrete cystic airspace and to characterize the morphologic and pathologic features of the cancer and the cystic airspace. MATERIALS AND METHODS We reviewed all diagnosed cases of lung cancer resulting from baseline screening (n=595) and annual screening (n=111) in the International Early Lung Cancer Action Program to identify those abutting or in the wall of a cystic airspace. We also reviewed the pathologic specimens. RESULTS A total of 26 lung cancers were identified abutting or in the wall of a cystic airspace. Of these, 13 were identified at baseline (13/595, 2%) and 13 at annual screening (13/111, 12%), which was significant (p<0.0001). The median circumferential portion of wall involved was less for the annual cancers than for the baseline ones, but this difference did not reach significance (90° vs 240°, p=0.07). The diagnosis was adenocarcinoma in all but three cases. Histologic analysis showed that the cystic space was a bulla, a fibrous walled cyst without a defined lining, or a pleural bleb and that in all but one case, the tumor was eccentric relative to the airspace and the wall of the airspace was unevenly thickened. CONCLUSION At annual repeat CT screening, the finding of an isolated cystic airspace with increased wall thickness should raise the suspicion of lung cancer.

CT- and computer-based features of small hamartomas

PURPOSE To identify characteristic computed tomographic (CT) and computer-derived features of hamartomas manifesting as small pulmonary nodules. METHODS Individuals with a diagnosis of hamartoma were identified among participants in the International Early Lung Cancer Action Program and were included if there thin section CT images that included the entire nodule. The CT findings were reviewed to determine the nodule consistency (solid, part-solid, nonsolid), nodule diameter (average of length and width), shape (round, lobulated, neither) and edge (smooth, not smooth). Computer measures of nodule compactness, sphericity, surface regularity and gradient (change in gray-scale between the nodule and the surrounding parenchyma) were determined. Volume doubling time (VDT) was also determined for those with at least two scans with similar imaging acquisitions. RESULTS A total of 21 cases of hamartomas that had histologic or cytologic confirmation were identified. The median age was 60 and 12 (57%) were men. Average diameter was 10.7 mm (5-20.7 mm). All were solid in consistency and were described by the radiologist as having either round or lobulated shape with a smooth edge. None had pathognomonic radiologic findings for hamartoma. Computer measures demonstrated that all were compact and spherical, with a regular surface and a sharp margin between the nodule and surrounding parenchyma. Of nine on whom the VDT could be calculated, eight had VDTs longer than 450 days. CONCLUSION Both radiologist and computer derived features of small hamartomas suggest a consistent presentation for these lesions which may be helpful in distinguishing them from other types of nodules.

CT screening for lung cancer: Value of expert review of initial baseline screenings

OBJECTIVE. Appropriate radiologic interpretation of screening CT can minimize unnecessary workup and intervention. This is particularly challenging in the baseline round. We report on the quality assurance process we developed for the International Early Lung Cancer Action Program. MATERIALS AND METHODS. After initial training at the coordinating center, radiologists at 10 participating institutions and at the center independently interpreted the first 100 baseline screenings. The radiologist at the institutions had access to the center interpretations before issuing the final reports. After the first 100 screenings, the interpretations were jointly discussed. This report summarizes the results of the initial 100 dual interpretations at the 10 institutions. RESULTS. The final institution interpretations agreed with the center in 895 of the 1000 interpretations. Compared with the center, the frequency of positive results was higher at eight of the 10 institutions. The most frequent reason of discrepant interpretations was not following the protocol (n = 55) and the least frequent was not identifying a nodule (n = 3). CONCLUSION. The quality assurance process helped focus educational programs and provided an excellent vehicle for review of the protocol with participating physicians. It also suggests that the rate of positive results can be reduced by such measures.