Abstract
To determine to what extent the ‘non-diagnostic’ lung scans made because of a clinical suspicion of pulmonary embolism enable further determination of the risk of pulmonary embolism.
Design
Retrospective.
Method
All non-diagnostic lung perfusion ventilation scans made in the Academic Medical Centre of Amsterdam in 1997 of 114 patients in succession (55 males and 59 females aged 27-85 years) were subjected to blind and independent re-evaluation by three observers (an experienced nuclear medicine expert, an experienced and an unexperienced interne) who, using a lung segment chart, estimated the risk of embolism as < 25, 25-50, 50-75 and > 75. They did this first without and then with the chest X-ray. The findings were grouped on the basis of accordance or non-accordance with the pulmonary angiogram. The interobserver agreement was calculated by means of kappa statistics.
Results
Of 58 patients the lung scan could be compared with a chest X-ray and a pulmonary angiogram. In 43 patients with a normal angiogram the observers in an average of 50 of the scans estimated the risk of pulmonary embolism as < 25, as against 25-50 in 27, 50-75 in 9 and > 75 in 5. In 15 patients with a deviant pulmonary angiogram, these figures were 22, 38, 20, and 12, respectively. The interobserver kappa for evaluation without chest X-ray was ≤ 0.16, as against ≤ 0.41 with the chest X-ray.
Conclusions
A reliable classification of the risk of pulmonary embolism was not possible on the basis of non-diagnostic lung scans, regardless of whether the patient did or did not have pulmonary embolism. The interobserver variability was less when the lung scan was evaluated together with the chest X-ray, but even so it was unacceptably high.
Design
Retrospective.
Method
All non-diagnostic lung perfusion ventilation scans made in the Academic Medical Centre of Amsterdam in 1997 of 114 patients in succession (55 males and 59 females aged 27-85 years) were subjected to blind and independent re-evaluation by three observers (an experienced nuclear medicine expert, an experienced and an unexperienced interne) who, using a lung segment chart, estimated the risk of embolism as < 25, 25-50, 50-75 and > 75. They did this first without and then with the chest X-ray. The findings were grouped on the basis of accordance or non-accordance with the pulmonary angiogram. The interobserver agreement was calculated by means of kappa statistics.
Results
Of 58 patients the lung scan could be compared with a chest X-ray and a pulmonary angiogram. In 43 patients with a normal angiogram the observers in an average of 50 of the scans estimated the risk of pulmonary embolism as < 25, as against 25-50 in 27, 50-75 in 9 and > 75 in 5. In 15 patients with a deviant pulmonary angiogram, these figures were 22, 38, 20, and 12, respectively. The interobserver kappa for evaluation without chest X-ray was ≤ 0.16, as against ≤ 0.41 with the chest X-ray.
Conclusions
A reliable classification of the risk of pulmonary embolism was not possible on the basis of non-diagnostic lung scans, regardless of whether the patient did or did not have pulmonary embolism. The interobserver variability was less when the lung scan was evaluated together with the chest X-ray, but even so it was unacceptably high.
| Translated title of the contribution | The value of the 'non diagnostic' lung scan - further classification according to the risk of pulmonary embolism not reliable |
|---|---|
| Original language | Dutch |
| Pages (from-to) | 1537-1542 |
| Journal | Nederlands tijdschrift voor geneeskunde |
| Volume | 144 |
| Publication status | Published - 11 Aug 2000 |