Detectability of peripheral lung cancer on chest radiographs: effect of the size, location and extent of ground-glass opacity

Influence of radiologic expertise in detecting lung tumors on chest radiographs

PURPOSE

To analyze the influence of radiologic expertise in detecting lung tumors on chest radiographs.

MATERIALS AND METHODS

We retrieved posteroanterior chest radiographs and CT examination obtained from 283 patients with solitary primary malignant lung tumors who underwent surgical resection. There were 176 men and 107 women with a mean age of 67.0±9.1 (SD) years (range: 33-88 years). Thirteen first-year post-graduate (PGY-1) trainees and nine pulmonary specialists (three radiologists, three thoracic surgeons, and three pulmonologists) interpreted the chest radiographs. Detection rates among trainees and specialists were compared using Student t test.

RESULTS

The total numbers of detected tumors ranged from 103 (36.4%) to 136 (48.1%) with a mean of 127.9±9.1 (45.2±3.2%) in the trainee group, and 137 (48.4%) to 182 (64.3%) with a mean of 161.6±13.1 (57.1±4.6%) in the specialist group; the intergroup difference was statistically significant (P<0.001). Significant intergroup detectability differences of >10% were noted for tumors in the peripheral zone with (i) ground glass opacity (GGO) ratio ≥10% and <70% and any size, or (ii) GGO ratio <10% and size ≤2cm; and for tumors hidden by the mediastinum, heart, or diaphragm with (i) GGO ratio ≥10% and <30% and size >3cm, or (ii) GGO ratio <10% and size >2cm.

CONCLUSION

Our study demonstrates significant differences in lung tumor detectability on chest radiographs between PGY-1 trainees and pulmonary specialists according to tumor size, extent of GGO, and tumor location.

Radiographers' performance in chest X-ray interpretation: the Nigerian experience

OBJECTIVE

To assess the performance of Nigerian radiographers in interpretation of plain chest radiographs and to assess whether age, years since qualification and sector of practice are associated with performance.

METHODS

A test set of 50 radiographs containing 23 cases with no pathology (normal) and 27 abnormal cases (cardiopulmonary conditions) independently confirmed by 3 radiologists were presented to 51 radiographers in a random order. Readers independently evaluated radiographs for absence or presence of disease and stated the location, radiographic features and diagnosis. Readers self-reported their age, years since qualification and sector of practice. Receiver operating characteristic was used to assess the performance. Mann-Whitney U test was used to assess whether age, years since qualification and sector of practice were associated with performance.

RESULTS

Mean location sensitivity was 88.9 [95% confidence interval (CI), 0.787-0.980]. Mean sensitivity and specificity were 76.9 (95% CI, 0.658-0.864) and 79.8 (95% CI, 0.658-0.864), respectively. Age was not associated with performance (p = 0.07). Number of years qualified as radiographer (p = 0.005) and private practice (p = 0.004) were positively associated with performance.

CONCLUSION

Nigerian radiographers can correctly report chest radiographs to a reasonable standard, and performance is associated with number of years since qualification and the sector of practice.

ADVANCES IN KNOWLEDGE

There are less than 300 radiologists serving a Nigerian population of about 170 million; therefore, X-ray interpretation by radiographers deserves consideration. Nigerian radiographers have potential to interpret chest X-ray in the clinical setting, and this may significantly improve radiology service delivery in this region.

Cost–effectiveness of endobronchial percutaneous biopsy compared with transthoracic biopsy for diagnosis of peripheral lung lesions

SUMMARY: 

Aim: This study compares the cost–effectiveness of radial endobronchial ultrasound (R-EBUS; Olympus Medical Systems Group, Tokyo, Japan) and electromagnetic navigation (ENB) to transthoracic needle biopsy (TTNB) to attain a confirmative diagnosis of the suspect lung lesions(s). Methods: The National Lung Screening Trial enrolled over 50,000 people aged 55–74 years with at least a 30-pack/year smoking history, in fairly good health and not symptomatic of lung disease. The study found low-dose computed tomography of the chest resulted in a 20% lower chance of dying from lung cancer compared with those who had chest x-rays. Approximately 25% of the low-dose computed tomography-screened patients had a positive screen requiring confirmation of the lung lesion. Using an estimate of 5.2 million annual chest CT scans in the USA as a basis for the number of patients seeking a confirmative result before being recommended for surgery for possible benign lung lesions our study seeks to identify the most cost-effective biopsy protocol to reduce costs, and deliver improved diagnostic accuracy. Results: Modeling 200 representative patients assigned to; TTNB, bronchoscopy, or R-EBUS-/ENB-enabled endobronchial percutaneous (Endo-Perc) when comparing procedure costs, insurance payment and clinical outcomes the Endo-Perc procedure resulted in the most cost-effective option to biopsy the suspect lung lesion. The lower adverse event profile of pneumothorax and reduced cost the Endo-Perc procedure resulted in a gain of US$130,464 compared with a loss of US$562,863 for TTNB, or a loss of US$103,487 for bronchoscopy. Conclusion: Our findings suggest combining R-EBUS with ENB delivers a high-diagnostic yield at a lower cost owing to the lower risk of a pneumothorax when compared with transthoracic lung biopsy.

Highly sensitive detection of cancer cells using femtosecond dual-wavelength near-IR two-photon imaging

We describe novel imaging protocols that allow detection of small cancer cell colonies deep inside tissue phantoms with high sensitivity and specificity. We compare fluorescence excited in Styryl-9M molecules by femtosecond pulses at near IR wavelengths, where Styryl-9M shows the largest dependence of the two-photon absorption (2PA) cross section on the local environment. We show that by calculating the normalized ratio of the two-photon excited fluorescence (2PEF) intensity at 1200 nm and 1100 nm excitation wavelengths we can achieve high sensitivity and specificity for determining the location of cancer cells surrounded by normal cells. The 2PEF results showed a positive correlation with the levels of MDR1 proteins expressed by the cells, and, for high MDR1 expressors, as few as ten cancer cells could be detected. Similar high sensitivity is also demonstrated for tumor colonies induced in mouse external ears. This technique could be useful in early cancer detection, and, perhaps, also in monitoring dormant cancer deposits.

Flat-panel detector computed tomography imaging: observer performance in detecting pulmonary nodules in comparison with conventional chest radiography and multidetector computed tomography

PURPOSE

The aim of this study was to compare the detectability of lung nodules on images obtained with a flat-panel detector computed tomography (FPD-CT) system and by chest radiographs (CXRs) using receiver-operating characteristic (ROC) analysis.

MATERIALS AND METHODS

FPD-CT was conducted with the patients in the sitting position. For the CXR study, the patients stood erect. Our study population consisted of 26 individuals ranging in age from 50 to 83 years. The reference standard was based on the interpretations obtained by consensus of 2 radiologists on multidetector CT images for the presence or absence of nodules. Four other radiologists independently assessed and recorded the absence or presence of lung nodules and their location on FPD-CT and CXR images. ROC analysis was used to evaluate lung nodule detectability by both imaging modalities.

RESULTS

Two radiologists identified 34 nodules whose diameter was 5 to 42 mm (mean, 19.3 mm) in 23 of the 26 study participants on the multidetector CT images. Overall, analysis of variance for ROC analysis showed that FPD-CT was significantly better in detecting nodules than CXR (P=0.02). The estimated mean Az value was 0.9818±0.0083 with FPD-CT and 0.7610±0.0908 with CXR. The sensitivity for nodule detection on FPD-CT and CXR images was 79.4% and 33.8%, respectively.

CONCLUSION

The detectability of pulmonary nodules was better on images of FPD-CT than on CXRs.