Objective: The aim of this study was to evaluate intra- and inter-observer reproducibility of sinus x-rays in comparison to sinus computed tomography (CT) in chronic rhinosinusitis (CRS) patients. Methods: This was a prospective controlled study for which 14 adult CRS patients were recruited. Patients underwent a sinus multi-detector CT scan as well as additional sinus x-rays at the same time. Symptom interview and skin prick tests were performed. Lund-Mackay (LM) scores and 43 other findings in paranasal sinuses were analyzed by three blinded observers from CT-scans and x-rays. We compared agreement between sinus CT and x-rays (intra-observer reproducibility) and between three observers (inter-observer reproducibility) by Cohen’s kappa. Results: In at least 90% of the cases, the status of 47/49 structures was detectable in CT scans, whereas the status of only 8/49 structures was detectable in x-rays. The majority of the 25 visualized structures had poor intra-observer and inter-observer reproducibility. Conclusion: Only a few structures can be visualized in paranasal sinus x-rays and compared to paranasal sinus CT-scans, their reproducibility is poor. Our results strongly support the current consensus of radiation dose reduction by limiting the number of x-rays.
Chronic rhinosinusitis (CRS) is a multifactorial and variable disease with a prevalence of 10.9% [
CRS surgery has improved many patients’ quality of life with hard to treat CRS [
Despite the novel low dose sinus CT scan modalities, the number of performed sinus x-rays is high in Finland (13.1 per 1000 inhabitants in 2011, according to the statistics of the Radiation and Nuclear Safety Authority) [
The study was approved by the ethics committee of the Pirkanmaa Hospital District (no 96032) and was conducted in accordance with the Helsinki Declaration of 1975, as revised in 1983. Written informed consent was obtained from each participant. Volunteer patients were exposed to an extra radiation dose of 0.02 years (6 days of natural background radiation in Finland).
This study was carried out in the Department of Otorhinolaryngology, at Tampere University Hospital, Finland from 2006 to 2015. A random sample of 14 adult CRS patients, who also had a history of AR and requiring sinus CT scans during 2007-2011, were enrolled. 3 (21%) out of 14 patients also had concomitant asthma. Having another severe disease was an exclusion criterion. 2 (85.7%) out of 14 patients reported as having other diseases (one had arrhythmia, one had resolved melanoma). None of the patients reported using regularly other medication than those due to inflammatory airway diseases. There was no patient record report of any other diseases, nor of psychiatric/psychologic disorders. Patient data was collected from medical records and by a questionnaire at the time of sinus CT scans, as previously described [
Patients underwent routine sinus multiple detector CT scans for clinical purposes. Two different CT scanners were used: GE LightSpeed 16 (GE Healthcare, Milwaukee, Wisconsin) and Philips Brilliance 64 (Philips, Best, Netherlands). Patients were scanned in a supine position with a kilovoltage of 120 kV and a milliampere second of 100 mAs. With the GE scanner, slice thickness was 0.625 mm with coronal reconstructions at 1.5 mm and a radiation dose of 0.8 mSv. With the Philips scanner, slice thickness was 0.9 mm with coronal reconstructions at 0.9 mm and a radiation dose of 0.9 mSv. Both were three dimensional (3D) in nature without any gaps. In all cases, imaging was performed using a bone filter technique. Scans covered the entire sinonasal area in both axial and coronal directions, starting from the nasal tip and ending at the posterior wall of the sphenoid sinuses.
X-rays were performed at the same time as sinus CT scans. Two X-ray projections, Waters and PA-projection (Caldwell), were taken with Philips Pendo Diagnost (Philips, Best, Netherlands) skull unit in a sitting position. Imaging parameters were 85 kV, 12 mAs with Waters, and in PA-projection 85 kV and 8 mAs. The images were captured using photostimulable phosphor plates, pixel size 0.1 mm and read with AGFA CR 25 CR (Agfa-Gevaert N. V. Mortsel, Belgium) system. The radiation dose of x-rays with two projections was 0.06 mSv.
CT scans and x-rays were observed by three independent observers blinded to each other and to patient history data: an experienced head and neck radiologist (AM), an experienced Ear Nose Throat (ENT)-and rhinosurgeon (JN), and a fifth year ENT resident (ST-S). Examination of the same patient’s images took place at least a week apart. The three observers filled a 49-item form of sinonasal structures from both CT-scan and x-ray bilaterally for each patient (
Statistical analysis was carried out by SPSS Base 15.0 Statistical Software Package (SPSS Inc., Chicago, IL, USA). Cohen’s kappa was used to compare the degree of agreement between CT scans and x-rays (e.g. intra-observer agreement); and the inter-observer agreement of x-rays. The calculation is based on the difference between how much agreement is actually present compared to how much agreement would be expected to be present by chance alone. The established interpretation of Kappa-value is classified into 6 subgroups: Poor < 0.2, Fair 0.21 - 0.4, Moderate 0.41 - 0.6, Good 0.61 - 0.8 and Very Good 0.81 - 1.0. A value under zero means that the agreement is worse than that by chance [
Patient characteristics are shown in
The number of visualized structures in x-rays was 25, e.g. the structures that were visualized in at least one patient´s paranasal sinus x-rays, whereas the number of visualized structures in at least one patient’s CT scan was 49 (
We compared the degree of agreement between x-rays and CT scans of the 25 structures that were visualized in x-rays. In general, the intra-observer agree-
Chronic rhinosinusitis patients | ||||
---|---|---|---|---|
n = 14 | % | |||
Gender | ||||
Male | 2 | 14.3 | ||
Female | 12 | 85.7 | ||
Age | ||||
<45 years | 11 | 78.6 | ||
≥45 years | 3 | 21.4 | ||
Smoking | ||||
No | 9 | 64.3 | ||
Ex | 3 | 21.4 | ||
Current | 1 | 7.1 | ||
Unknown | 1 | 7.1 | ||
Allergic rhinitis | ||||
No | 2 | 14.3 | ||
Yes | 11 | 78.6 | ||
Unknown | 1 | 7.1 | ||
SPT positivity | ||||
No | 3 | 21.4 | ||
Only pollen(s) | 5 | 35.7 | ||
Only animal dander(s) | 1 | 7.1 | ||
Multiple allergen types | 5 | 35.7 | ||
Asthma | ||||
No | 10 | 71.4 | ||
Yes | 3 | 21.4 | ||
Unknown | 1 | 7.1 | ||
Nasal polyps | ||||
No | 12 | 85.7 | ||
Yes | 1 | 7.1 | ||
Unknown | 1 | 7.1 | ||
AERD | ||||
No | 13 | 92.9 | ||
Yes | 0 | 0.0 | ||
Unknown | 1 | 7.1 |
Other diseases2 | |||
---|---|---|---|
No | 12 | 85.7 | |
Yes | 2 | 14.3 | |
Current use of intranasal corticosteroids | |||
No | 1 | 7.1 | |
Yes | 12 | 85.7 | |
Unknown | 1 | 7.1 | |
≥1 peroral corticosteroid course(s) during the past 1 year | |||
No | 13 | 92.9 | |
Yes | 0 | 0.0 | |
Unknown | 1 | 7.1 | |
Previous sinonasal operation(s) | |||
No | 11 | 78.6 | |
Yes | 2 | 14.3 | |
Unknown | 1 | 7.1 | |
Radiological signs in CT scans of previous sinus operation | |||
No | 11 | 78.6 | |
Yes | 3 | 21.4 | |
Total Lund-Mackay score of CT scans | |||
0 - 3 | 7 | 50.0 | |
4 - 12 | 7 | 50.0 | |
13 - 24 | 0 | 0.0 | |
Sinonasal operation performed within a year after the CT scans | |||
No | 5 | 35.7 | |
Yes | 8 | 57.1 | |
Unknown | 1 | 7.1 | |
≥1 sinonasal operation(s) during the 6-year follow-up | |||
No | 12 | 85.7 | |
Yes | 1 | 7.1 | |
Unknown | 1 | 7.1 | |
Number of antibiotic courses during the past 2 years, median (min-max) | 6.0 | (2 - 15) | |
Duration of symptoms in years, median (min-max) | 2.5 | (0.3 - 25.0) | |
Current symptoms by VAS, mean (min?max) | |||
Sense of smell | 3.7 | (0.0 - 7.3) | |
Post-nasal drip | 5.5 | (1.0 - 8.1) | |
Obstruction | 6.1 | (0.7 - 9.8) | |
Facial pain | 5.5 | (2.4 - 9.9) |
Abbreviations: SPT = skin prick test; AERD = patient-reported aspirin exacerbated respiratory disease; CT = computed tomography; VAS= visual analogue scale (0 - 10). 1At least one peroral corticosteroid treatment during the last 12 months. 2Self-reported and patient-record information.
Visualized in x-rays | Non-visualized in x-rays | ||||
---|---|---|---|---|---|
Non-detectable cases% | Non-detectable cases% | ||||
CT-scans | x-rays | CT-scans | x-rays | ||
Atrophy-normal hypertrophy of inferior turbinate | 0.0 | 28.6 | Anterior ethmoidal artery | 25.0 | 100.0 |
Atrophy-normal hypertrophy of middle turbinate | 3.6 | 50.0 | Atrophy-normal hypertrophy of superior turbinate | 21.4 | 100.0 |
Hypoplasia/normal/hyperplasia of anterior ethmoidal sinus | 0.0 | 14.3 | Contact to middle turbinate of orbital lamina of ethmoidal bone | 0.0 | 100.0 |
Hypoplasia/normal/hyperplasia of frontal sinus | 0.0 | 14.3 | Frontal recess | 0.0 | 100.0 |
Hypoplasia/normal/hyperplasia of maxillary sinus | 0.0 | 14.3 | Infraorbital cell | 0.0 | 100.0 |
Hypoplasia/normal/hyperplasia of posterior ethmoidal sinus | 0.0 | 14.3 | Keros classification | 0.0 | 100.0 |
Hypoplasia/normal/hyperplasia of sphenoid sinus | 0.0 | 14.3 | Lund-Mackay ostiomeatal unit | 0.0 | 100.0 |
Lund-Mackay anterior ethmoidal sinus | 0.0 | 0.0 | Mucosa of pneumatized middle turbinate | 0.0 | 100.0 |
Lund-Mackay frontal sinus | 0.0 | 7.1 | Mucosa of pneumatized superior turbinate | 0.0 | 100.0 |
Lund-Mackay maxillary sinus | 0.0 | 0.0 | OMC region, accessory maxillary sinus ostium | 7.1 | 100.0 |
Lund-Mackay posterior ethmoidal sinus | 0.0 | 7.1 | OMC region, hiatus | 0.0 | 100.0 |
Lund-Mackay sphenoid sinus | 0.0 | 3.6 | OMC region, infundibulum | 0.0 | 100.0 |
Mucosa of nasal cavity (extent of edema) | 0.0 | 14.3 | OMC region, maxillary antrum | 0.0 | 100.0 |
Mucosa of nasal cavity (normal-polypous) | 0.0 | 14.3 | OMC region, pneumatized superior attachment of uncinate process | 0.0 | 100.0 |
Need for septoplasty1 | 0.0 | 35.7 | OMC region, prominent ethmoid bulla | 0.0 | 100.0 |
Septal deviation obstructing middle meatus | 0.0 | 32.1 | OMC region, superior attachment of uncinate process | 7.1 | 100.0 |
Septum, crest | 0.0 | 17.9 | Optic nerve | 0.0 | 100.0 |
Septum deviation | 0.0 | 21.4 | Sphenoethmoidal recess | 3.6 | 100.0 |
Septum turbinate | 0.0 | 32.1 | Paradoxical middle turbinate | 0.0 | 100.0 |
Septum, spur | 0.0 | 21.4 | Paradoxical superior turbinate | 7.1 | 100.0 |
Sinus mucosal abnormalities of anterior ethmoidal sinus | 0.0 | 7.1 | Pneumatized middle turbinate | 0.0 | 100.0 |
Sinus mucosal abnormalities of frontal sinus | 0.0 | 17.9 | Pneumatized superior turbinate | 7.1 | 100.0 |
Sinus mucosal abnormalities of maxillary sinus | 0.0 | 3.6 | Previous sinus surgery performed | 0.0 | 100.0 |
Sinus mucosal abnormalities of posterior ethmoidal sinus | 0.0 | 7.1 | Thickness of orbital lamina of ethmoidal bone | 0.0 | 100.0 |
Sinus mucosal abnormalities of sphenoid sinus | 0.0 | 10.7 |
The CT scans and x-rays were taken from 14 patients with chronic rhinosinusitis symptoms. Each patient underwent CT scans and x-rays at the same time. The columns show in alphabetical order the evaluated 49 structures from paranasal sinus CT-scans and x-rays. Visualized in x-rays = the 25 structures that were visualized in at least one patient’s paranasal sinus x-rays (left column); Non-visualized in x-rays = the 24 structures that were non-visualized in paranasal sinus x-rays of all cases (right column); OMC = Ostiomeatal complex; Not detectable = the percentage of the observer´s responses “The status of the structure is not detectable” of both sides. 1Evaluated by the ENT surgeon. Other structures evaluated by the radiologist.
ment was poor (kappa < 0.2) in the majority of structures, such as LM scores. Moderate and good agreement was only achieved for gross anatomical structures on the right hand-side only, concerning respectively, nasal septum deviation and size of the frontal sinus (
The 25 structures that were visualized in x-rays were evaluated by a radiologist, an ENT surgeon and an ENT resident. The inter-observer agreement between radiologist and ENT resident for x-rays was poor (kappa ≤ 0.02) in 88% of the structures and fair (kappa 0.21 - 0.4) for the rest (12%) of the structures. The agreement between radiologist and ENT surgeon for x-rays was poor or fair in 80% of the structures and the agreement between ENT surgeon and ENT resident was poor or fair in 92% of the structures.
This study was carried out to evaluate intra- and inter-observer reproducibility of sinus x-rays in comparison to sinus CT scans. When this study was started, multi- detector CT scans had a high radiation dose (in average 0.9 mSv) and x-rays were still relative widely used due to a clearly smaller radiation dose (in average 0.03 mSV per image). After this, low-dose CT scans (such as cone beam CT scans) have emerged (radiation dose between 0.08 - 0.27 mSv) and hence have largely replaced both sinus x-rays and high-dose sinus CT scans [
Our main finding was that a small proportion of structures can be visualized in x-rays; and x-ray evaluations have poor reproducibility. CRS specific changes that should be observed in CT-scans including degree of opacification of the paranasal sinuses and/or obstruction of the ostiomeatal complex cannot be visualized or only poorly in simple x-rays, making CRS diagnosis unreliable [
Intra-observer agreement was fair to poor regarding most of the 25 structures that could be visualized in plain x-rays. Similarly to us, others report in a study with 47 patients with acute rhinosinusitis that plain sinus radiograms have a low sensitivity for detecting sinus inflammatory changes in other paranasal sinuses besides the maxillary sinus, in comparison to CT-scans [
Inter-observer agreement was poor for the majority of structures that could be visualized by the radiologist, ENT surgeon and ENT resident. Very good inter- observer agreement was only achieved in regard to structures that could not be visualized, between ENT resident and surgeon.
Computed tomography scans vs. x-rays | ||||
---|---|---|---|---|
Right kappa | P | Left kappa | P | |
Lund-Mackay frontal sinus | −0.057 | <0.001 | −0.050 | <0.001 |
Lund-Mackay anterior ethmoidal sinus | 0.109 | 1.00 | 0.243 | 0.357 |
Lund-Mackay posterior ethmoidal sinus | 0.155 | <0.001 | 0.200 | <0.001 |
Lund-Mackay sphenoid sinus | −0.148 | <0.001 | 0.323 | 0.286 |
Lund-Mackay maxillary sinus | 0.125 | 0.560 | 0.087 | 1.00 |
Sinus mucosal abnormalities of frontal sinus | −0.120 | 1.00 | 0.192 | 1.00 |
Sinus mucosal abnormalities of anterior ethmoidal sinus | 0.155 | <0.001 | 0.114 | 1.00 |
Sinus mucosal abnormalities of posterior ethmoidal sinus | 0.142 | <0.001 | 0.067 | 1.00 |
Sinus mucosal abnormalities of sphenoid sinus | 0.058 | <0.001 | 0.233 | 1.00 |
Sinus mucosal abnormalities of maxillary sinus | 0.355 | <0.001 | 0.339 | <0.001 |
Hypoplasia/normal/hyperplasia of frontal sinus | 0.650 | <0.001 | 0.344 | <0.001 |
Hypoplasia/normal/hyperplasia of anterior ethmoidal sinus | 0.000 | <0.001 | 0.000 | <0.001 |
Hypoplasia/normal/hyperplasia of posterior ethmoidal sinus | 0.000 | <0.001 | 0.000 | <0.001 |
Hypoplasia/normal/hyperplasia of sphenoid sinus | 0.192 | <0.001 | 0.208 | <0.001 |
Hypoplasia/normal/hyperplasia of maxillary sinus | 0.000 | <0.001 | 0.000 | <0.001 |
Need for septoplasty1 | 0.114 | 1.00 | 0.114 | 1.00 |
Septal deviation obstructing middle meatus | 0.079 | 1.00 | 0.114 | 1.00 |
Septum turbinate | 0.000 | <0.001 | 0.000 | <0.001 |
Septum deviation | 0.462 | <0.001 | 0.385 | <0.001 |
Septum, crest | 0.133 | <0.001 | −0.061 | 1.00 |
Septum, spur | 0.023 | <0.001 | −0.094 | <0.001 |
Atrophy-normal-hypertrophy of inferior turbinate | 0.250 | <0.001 | 0.381 | .019 |
Atrophy-normal-hypertrophy of middle turbinate | −0.083 | 0.143 | −0.051 | <0.001 |
Mucosa of nasal cavity (extent of edema) | 0.030 | 0.250 | −0.054 | <0.001 |
Mucosa of nasal cavity (normal-polypous) | 0.175 | <0.001 | −0.054 | 1.00 |
Agreement | kappa |
---|---|
Poor | ≤0.2 |
Fair | 0.21 - 0.4 |
Moderate | 0.41 - 0.6 |
Good | 0.61 - 0.8 |
Very good | 0.81 - 1.0 |
The CT scans and x-rays were taken from 14 patients with chronic rhinosinusitis symptoms. Each patient underwent CT scans and x-rays at the same time. Agreement is presented only of the 25 structures that were detected in x-rays (
Simple X-rays of sinuses are currently used to exclude acute sinusitis. Long- term smoking, decline in lung function and poor health-related quality of life are risk factors for exacerbation of asthma exacerbations and emergency room [
The limitation of our study is the small sample size, which was due to ethical reasons and to difficulties in recruiting volunteer patients for additional x-ray images, carrying extra radiation. We acknowledge that small sample size hinders large scale extrapolation of results and selection bias may have occurred.
Only a very small number of structures can be visualized in paranasal sinus x-rays and their evaluation reproducibility is poor compared to paranasal sinus CT scans. Despite the small study sample size, our results strongly support the current European position paper on rhinosinusitis and nasal polyps consensus that sinus CT-scans are needed when estimating the need for surgical treatment of CRS (
The authors thank MD Mikko Suvinen and MD Anna-Maija Kuukka for collaboration and research nurse Marja-Leena Oksanen for her excellent assistance.
The study was supported in part by research grants from the Ahokas Foundation, Competitive Research Funding of the Tampere University Hospital (Grants 9H067, 9J108, 9L087), the Finnish Cultural Foundation, the Finnish Association of Otorhinolaryngology and Head and Neck Surgery, the Finnish Medical Society Duodecim, the Finnish Society of Allergology and Immunology, Helsinki University Central Hospital Research Funds, the Tampere Tuberculosis Foundation, the Ida Montin Foundation, the Jane and Aatos Erkko Foundation, the Väinö and Laina Kivi Foundation and the Yrjö Jahnsson Foundation. The authors report no conflicts of interest.
Luukkainen, A., Terna, E., Numminen, J., Markkola, A., Dastidar, P., Jarnstedt, J., Huhtala, H., Karjalainen, M., Blomgren, K., Kauppi, P., Rautiainen, M. and Toppila-Salmi, S. (2017) Poor Reproducibility in the Evaluation of Paranasal Sinus X-Rays in Chronic Rhinosinusitis. Open Journal of Radiology, 7, 23- 34. https://doi.org/10.4236/ojrad.2017.71003