Screen-detected subsolid pulmonary nodules: long-term follow-up and application of the PanCan lung cancer risk prediction model.

OBJECTIVE: To report the long-term follow-up of subsolid nodules (SSNs) detected in participants of a prospective low-dose CT lung cancer screening cohort, and to investigate the utility of the PanCan model in stratifying risk in baseline SSNs. METHODS: Participants underwent a baseline scan, two annual incidence scans and further follow-up scans for the detected nodules. All SSNs underwent a minimum of 2 years of follow-up (unless resolved or resected). Risk of malignancy was estimated using the PanCan model; discrimination [area under the receiver-operating characteristic curve (AUC)] and calibration (Hosmer-Lemeshow goodness-of-fit test) were assessed. The Mann-Whitney U-Wilcoxon test was used to compare estimated risk between groups. RESULTS: 70 SSNs were detected in 41 (16.0%) out of 256 total participants. Median follow-up period was 25.5 months (range 2.0-74.0 months). 29 (41.4%) SSNs were transient. Five (7.1%) SSNs were resected, all found to be Stage I lung adenocarcinoma, including one SSN stable in size for 3.0 years before growth was detected. The PanCan model had good discrimination for the 52 baseline SSNs (AUC = 0.89; 95% confidence interval 0.76-1); the Hosmer-Lemeshow goodness-of-fit test was non-significant (p = 0.27). Estimated risk was significantly higher in the baseline SSNs found to be cancer vs those not found to be cancer after 2-6 years of follow-up (p < 0.01). CONCLUSION: Our findings support a long-term follow-up approach for screen-detected SSNs for 3 years or longer. The PanCan model appeared discriminatory and well calibrated in this cohort. ADVANCES IN KNOWLEDGE: The PanCan model may have utility in identifying low-risk SSNs which could be followed with less frequent CT scans.

Using DynaCT for the assessment of ilio-femoral arterial calibre, calcification and tortuosity index in patients selected for trans-catheter aortic valve replacement.

Adequate vascular access for femoral trans-catheter aortic valve replacement is fundamental to the success of the procedure. Assessment of vascular calibre, tortuosity and calcification is performed by angiography and multi-slice computed tomography (MSCT). Can DynaCT provide the same information as MSCT? 15 Patients underwent MSCT, angiography and DynaCT. Vessel diameter measurements were taken in three positions of the left and right ilio-femoral arteries. Tortuosity was assessed using an index of the direct distance and the distance taken by the artery between two points. Calcification was assessed in MSCT and DynaCT using a simple scoring system. Concordance correlation coefficient of arterial calibre between angiography and MSCT was 0.96 (95 % CI 0.94-0.97). DynaCT and angiography was 0.94 (95 % CI 0.91-0.96) and Dyna CT and MSCT, 0.95 (95 % CI 0.92-0.97). Bland-Altman tests demonstrate a mean difference between the angiogram and the MSCT of 0.06 mm (+0.97, -1.42), angiogram and DynaCT, 0.13 mm, (+1.00, -0.87), DynaCT and MSCT, 0.2 mm, (+1.15, -0.76). Tortuosity comparisons gave a median tortuosity index for MSCT 1.29 and DynaCT 1.23 (p = 0.472). Calcification comparisons of MSCT and DynaCT using correlation coefficients demonstrate a correlation of 0.245 (p = 0.378). Effective radiation doses were: DynaCT; 3.63 ± 0.65 mSv and angiography; 0.57 ± 0.72 mSv, MSCT; 7.15 ± 2.58 mSv. DynaCT is equal to MSCT and angiography in assessing femoral artery calibre. Like MSCT, it can assess tortuosity and can produce 3D images but is inferior in the assessment of calcification.

Does addition of CT pelvic venography to CT pulmonary angiography protocols contribute to the diagnosis of thromboembolic disease?

AIM: To evaluate the contribution which addition of pelvic computed tomography venography (CTV) to a standard CT pulmonary angiography (CTPA) imaging protocol makes to a definitive diagnosis of thromboembolic disease. MATERIALS AND METHODS: One hundred and six consecutive patients over the age of 55 years referred for (CTPA) for suspected pulmonary embolism between June and November 1999 had pelvic CTV performed at the time of the CTPA study. RESULTS: Ninety-six of 106 CTPA studies were technically adequate. In total, 29/96 (29.6%) CTPA studies were positive for pulmonary embolism, 10/96 (10.4%) CTV studies were positive and five of these 10 examinations showed venous thrombus when the CTPA study was negative (n = 4) or equivocal (n = 1). CONCLUSION: Addition of CTV shows residual thrombus in the pelvis in a proportion of patients with positive CTPA studies and demonstrates venous thrombus in a small number of patients with no CT evidence of pulmonary embolism.