Eur. Radiol. 6, 553-556 (1996) © Springer-Verlag 1996

European Radiology

Original article

Another CT sign of sinonasal polyposis: truncation of the bony middle turbinate E. Y. Liang 1, W. W. M. Lam 1, J. K. S. Woo 2, C. A. Van Hasselt 2, C. Metreweli 2

1 Department of Diagnostic Radiology and Organ Imaging, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong

2 Division of Otorhinolaryngology, Department of Surgery, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.

Received 9 May 1995; Revised version received 31 July 1995; Accepted 12 September 1995

ment plan [2-4]. Maximum medical treatment should be given before opting for surgery. Computed tomogra- phy is required to properly evaluate deeper pathology within the sinuses and behind the obstructing polyp which is not visualized with endoscopy [1]. Sinus CT is therefore important to confidently diagnose SNP and assess its extent and severity. Our aim was to study the features of SNP on coronal sinus CT, and to report a new sign: truncation of the bony middle turbinate.

Introduction

The development of functional endoscopic sinus surgery (FESS) provides a tool by which surgeons can accu- rately diagnose, and meticulously and atraumatically perform, surgery for nasal polyp disease [1]. However, sinonasal polyposis (SNP) remains a significant chal- lenge to the treating physician. Endoscopic surgery for sinonasal polyposis (SNP) is more extensive, more risky and the results are not as good as other patterns of si- nusitis. Medical treatment is the mainstay of the treat-

Materials and methods

We reviewed retrospectively coronal sinus CT of 100 consecutive patients. All patients had significant symp- toms suggesting recurrent inflammatory sinonasal dis- ease and, FESS was being considered when CT was re- quested. They all had a period of medical treatment prior to CT scanning in order to demonstrate medically nonreversible disease on CT. There were 52 males and 48 females; all were Hong Kong Chinese; age ranged from 7 to 74 years.

Sinonasal polyposis was the commonest pattern found in 34 patients. Seven patients did not have com- plete documentation and were rejected for further anal- ysis. A total of 21 patients had final FESS diagnosis of SNR Six patients had endoscopic examination but no surgery: 5 patients had polyposis and 1 did not have na- sal polyposis on endoscopy, but clearly had extensive bi- lateral polypoidal lesions in the sinuses on CT. The 27 SNPs with complete documentation were analysed. The incidence of our new sign "truncation of bony mid- dle turbinate" were noted. Previously reported CT fea- tures [6], namely polypoidal mass, widened infundibu- lum, bony trabecular attenuation and lateral bulging of lamina papyracea, were also evaluated.

Correspondence to: E.Y. Liang

554 E.Y. Liang et al.: Another CT sign of sinonasal polyposis

E.Y. Liang et al.: Another CT sign of sinonasal polyposis 555

Table 1. Frequencies of various features of sinonasal polyposis on coronal sinus CT in the current series and compared to the series of Drut- man et al. [6]

Features Liang & Lam et al.

Incidence Percentage

Drutman et al.

Bilateral involvement (%) Percentage

Polypoidal mass 22 of 27 81 Widened infundibulum 26 of 27 96 Bony trabecular attenuation 23 of 27 85 Lateral bulging of lamina papyracea 3 of 27 11 Truncation of bony middle turbinate 15 of 26 a 58

8~ (~8 of ~) 9~ 88 (23 of 26) 89

100 (23 of 23) 63 66 (2 of 3) 51 80 (12 of 15) -

a One patient who had previous bilateral middle turbinectomies was excluded from calculation; all 15 patients included had no history of previous turbinectomy

Table 2. Pattern of inflammatory sinus disease in the current series and compared to the series of Harnsberger et al. [5]

Disease-patterns Liang & Lam et al. Harnsberger et al. (%) (%)

SNP 34 10 OMU 37 25 Infundibulum 18 26 SER 1 6 Sporadic 20 24 Normal 3 27

NOTE: In some patients there is simultaneous occurrence of more than one pattern resulting in the total of all percentages greater than 100

We no ted the presence of a previously undescr ibed sign: t runca t ion of the b o n y middle turbinate . The bul- bous par t of the b o n y middle turbinate was missing, leaving beh ind a variable length of the vertical lamellar par t of the b o n y middle turbinate. The sign was present in 16 of the 27 SNP patients. O n e of these pat ients had previous bilateral middle turbinectomies . Thus, the inci- dence of this fea ture was 15 of 26 (58 %); 13 of 15 (87 %) were bilateral. This sign was no t found in o ther pat terns of i n f l ammato ry sinus disease.

Discuss ion

Results

The CT features of these 27 SNPs are summar ized and c o m p a r e d with the findings of D r u t m a n et al. [6] in Ta- ble 1. All our SNPs were bilateral. There was a s t rong t endency for extensive invo lvement including the poste- rior e thmoid and sphenoid, which were m u c h less com- mon ly involved in o ther pat terns of sinusitis.

Fig.1. Normal appearance of the bony middle turbinates (short thin arrows) despite adjacent inflammatory changes. Osteomeatal unit pattern on the left side, with mucosal thickening in the left eth- moid and maxillary sinus (thick arrows), narrow left infundibulum occluded by thickened mucosa (long thin arrow) leading towards the hiatus semilunaris and the middle meatus, both with thickened mucosa. On the right there is a mucus retention cyst in the antrum

Fig. 2. Sinonasal polyposis without truncation of bony middle tur- binates. There is bilateral symmetrical extensive involvement of maxillary sinuses, ethmoidal sinuses and the middle meati. The fol- lowing are noted: polypoidal masses (asterisks), the grossly wid- ened infundibula (stars), the remains of the eroded uncinate pro- cess (arrow), lateral bulging of lamina papyracea (large arrow- heads), and attenuation of ethmoid bony trabeculae. The bony middle turbinates are not yet truncated, but are eroded on the right side (small arrowheads)

Fig.3. Sinonasal polyposis with bilateral truncation of middle tur- binates (arrowheads). Note the bilateral symmetrical involvement: polypoidal masses (stars) and the widened infundibula (asterisks). Also note the deossification of the nasal septum

Fig.4. Sinonasal polyposis with unilateral truncation of bony mid- dle turbinate. Note the bilateral, but asymmetrical, involvement that on the left side is more severe than on the right side. The left bony middle turbinate is truncated (black arrow) whilst the right one (white arrow) is intact. Note also the widened infundibulum on the left (asterisk)

Sinonasal polyposis is relat ively c o m m o n in our locality. The relat ive incidence of SNP d iagnosed on corona l si- nus CT in our series is m o r e than three t imes that of Ha rnsbe rge r et al.'s series (Table 2), a l though the same CT diagnostic criteria were used [5]. The difference could be due to a var ie ty of reasons. There m a y be a dif- ference in genet ic allergic predisposi t ion and mucosa l hyperreact ivi ty; different env i ronmenta l factors m a y also be impor tant . Refer ra l pa t terns were p robab ly dif- ferent. Because we had m u c h lower incidence of no rma l sinus CT, our pat ients were m o r e likely to be long to a se- lected g roup with severe and recur ren t symptoms. These pat ients were m o r e likely to have SNP than o ther pat- terns of i n f l ammato ry sinus disease.

Inc idence of var ious a l ready- recognized CT features of SNP in our series was similar to that r epor ted by D r u t m a n et al. (Table 1), except tha t lateral bulging of lamina papyracea was less c o m m o n in our series.

Polypoidal masses in nasal vault and within sinuses were very c o m m o n in bo th series. W h e n the nasal vault or sinus was comple te ly opaque , the presence o f polyps was no t apprec ia ted [7].

Widen ing of in fundibu lum was also c o m m o n in bo th series. This sign can occur in diseases such as an t rochoana l polyp, inver ted papi l loma or any o ther condi t ions where there is a s low-growing mass within the in fundibu lum expanding it. However , when there is bilateral widening toge the r with o ther signs of ex- tensive sinusitis, SNP would be the mos t likely diagno- sis. All our SNP pat ients have bilateral sinus involve- ment . Pansinusit is with extensive and bilateral in- • vo lvemen t is a s t rong suggest ion o f SNR ra ther than neoplast ic condit ion, which tends to be focal and uni- lateral.

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Ethmoid bony trabecular at tenuation was more com- mon in our series. It is our empirical observation that the degree of deossification is related to chronicity of symptomatic SNR

Truncation of the bony middle turbinate was charac- teristic and easily recognizable. It is likely to be due to deossification caused by mechanical pressure erosion from polyposis as well as hyperaemia from mucosal in- flammation. As with ethmoid bony trabecular attenua- tion, the presence of this sign might be related to chro- nicity of the disease. Usually, it is the bulbous part of the bony middle turbinate that is missing and the verti- cal part remains intact. In patients with previous middle turbinectomy, the resection is high at the root of the middle turbinate and the vertical part is also missing. I n the absence of previous middle turbinectomy, we found this sign to be specific for SNP and not observed in other patterns of inflammatory sinus disease.

Conclusion

Computed tomography is an important adjunct to endo- scopy in preoperat ive assessment of patients with chron- ic sinus disease. It is important to diagnose sinonasal polyposis preoperat ively so that medical t rea tment is

E.Y. Liang et al.: Another CT sign of sinonasal polyposis

maximized before opting for surgery. Truncation of the bony middle turbinate is a characteristic and easily rec- ognizable sign. This new sign is not a cardinal sign, but is instead an ancillary sign. It appears to be specific to SNR and it does add confidence in the diagnosis.

References

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3. Lildholt T, Fogstrup J, Gammelgaard Net al. (1988) Surgical versus medical treatment of nasal polyps. Acta Otolaryngol (Stockh) 105:140-143

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