Chinese-German Journal of Clinical Oncology

December 2009, Vol. 8, No. 12, P719–P721

DOI  10.1007/s10330-009-0133-4

Study of MR image for involvement of paranasal sinuses in 56 cases with nasopharyngeal carcinoma Lusi Chen, Guangyu Wei, Xuefeng Hu, Xiaohong Zeng, Qiuxia Lu Department of Radiation Oncology, Cancer Hospital, Frist People’s Hospital of Foshan, Foshan 528000, China Received: 17 July 2009 / Revised: 20 August 2009 / Accepted: 25 September 2009 Abstract   Objective: The aim of the study was to study the nuclear magnetic resonance image (MRI) feature for involvement of paranasal sinuses in patients with nasopharyngeal carcinoma (NPC). Methods: The MRI of 56 patients with NPC and paranasal sinuses infringed were evaluated between December 2003 and August 2004. Results: Among them, 56 (100%) showed breakage in the wall of paranasal sinuses, 29 (51.8%) had thick mucous membrane in sinuses, 36 (64.3%) showed tumour invasion sinuses, 55 (98.2%) connected with primary carcinoma with the lesion, and 14 (25%) stored up fluid in sinuses. On MRI scan technique, the positive ratios of diagnoses were 66.1%, 76.8%, and 98.2% respectively (P < 0.000) in the horizontal section, coronal section and sagittal section. And nearly 60% was in the T1W1 and T2W1, but 100% in strengthen scan. Conclusion: The findings of sinuses wall breakage, thick mucous membrane in sinuses, tumour invasion cavity connective mass, and same enhancement signal in MR image may indicate the paranasal sinuses involved by primary tumour. The sagittal section and enhanced MRI scans are helpful to diagnosis. Key words  nasopharyngeal carcinoma (NPC); paranasal sinuses; nuclear magnetic resonance image (MRI)

The nuclear magnetic resonance image (MRI) improved the positive rate of diagnosis in patients with nasopharyngeal carcinoma (NPC) and paranasal sinuses infringed, recently. But the reports about MRI features for involvement of paranasal sinuses in NPCs were less. In the study, the MRI features of 56 patients with NPC and paranasal sinuses infringed were evaluated between December 2003 and August 2004. And that would be propitious to therapy.

Materials and methods Clinical data Fifty-six NPC patients with paranasal sinuses infringed were reviewed. There were 42 males and 14 females. The age ranged from 14 to 79 years, and the mean age was 49.5 years. All patients were diagnosed by pathology, and made MRI check before therapy. MRI data The MRI data of 56 NPC patients saved in the PACStapionPM 3.0 image scan system, could be scanned at any moment.

Correspondence to: Lusi Chen. Email: [email protected]

Study methods All patients made 1.5 T MRI check on their backs. The tier thickness of MRI scan was 6 mm, and the space between tiers was 1 mm. All cases were gathered the enhanced MRI scan in sagittal section, coronal section and horizontal section, and gathered the T1W1, T2W1 MRI scan at the same time. By means of the tumour in involvement of sinus and sinuses wall, mucous membrane in sinuses, the encroaching routes were conjectured. We compared the positive rates of diagnosis in each scan lists. All the MRI scan results were read by one radiation doctor and two radiotherapy doctors. MRI diagnosis for involvement of paranasal sinuses Tumour destroyed sinuses wall, or intruded into sinuses and lock-in sinuses in one MRI scan list. The whole tumour had the same signal. It showed equal signal or lower signal in T1W1 MRI scan. It showed equal signal or higher signal in T2W1 MRI scan. And it showed obvious enhancement in the enhanced MRI scan. Statistical analysis The positive rates of paranasal sinuses infringed in each MRI scan list were compared by χ2 test. While P < 0.05, it was positive in statistical analysis.

720 Table  1  patients

www. springerlink. com/content/1613-9089 The MRI features of paranasal sinuses infringed in 56 NPC

MRI Paranasal sinuses infringed Sinus sphenoidalis Sinus ethmoidales Sinus maxillaris MRI features Breakage in the wall of paranasal sinuses Thick mucous membrane in sinuses Tumour invasion sinuses Connected with primary carcinoma with the lesion Stored up fluid in sinuses Degrees of paranasal sinuses infringed Only breakage in the wall or/and thick mucous membrane in sinuses Tumour invasion sinuses Multiple sinuses infringed With clivus infringed Only breakage in the wall or/and thick mucous membrane in sinuses Tumour invasion sinuses Multiple sinuses infringed

n

Percent

56 9 7

100.0 16.1 12.5

56 29 36 55 14

100.0 51.8 64.3 98.2 25.0

20

35.7

25 11

44.6 19.7

9

45.0

22 11

88.0 100.0

Table  2  The positive rates of paranasal sinuses infringed in each MRI scan list MRI scan list Horizontal section Coronal section Sagittal section T1 T2 Strengthen scan

Positive cases

%

P

37 43 55 34 33 56

66.1 76.8 98.2 60.7 58.9 100.0

χ = 19.006 P = 0.000 2

χ2 = 30.777 P = 0.000

Results The circs of paranasal sinuses infringed and MRI features were showed in Table 1. The positive rates of paranasal sinuses infringed in each MRI scan list were showed in Table 2. The patients missed diagnosis in horizontal section or coronal section MRI scan lists were all sinus sphenoidalis lesions in the study. In the patients missed diagnosis in horizontal section MRI scan list, 5 cases had tumour invasion sinuses, and 14 cases hadn’t; but in coronal section, only one patient had tumour invasion sinuses, 12 cases hadn’t.

tumour and inflammation inside the sinus by multiple MRI scan lists and strengthen scan. So MRI had higher positive rate of diagnosis than CT in patients with NPC and paranasal sinuses infringed, and that was propitious to therapy [2]. Comprehending the image features in sinuses infringed was very importance. In the study, the MRI scan showed the sinuses wall breakage and tumour signal filling in breakage in 100% patients. It also showed thick mucous membrane inside sinuses in 51.8% cases. The thickness of mucous membrane in sinus forehead and sinus sphenoidalis was less than 2 mm, and in sinus maxillaris or sinus ethmoidales was less than 5 mm as a rule [3]. So the thick mucous membrane and equal signal or higher signal in T2W1 MRI scan were considered tumour encroaching [4]. In the team, the MRI scan of 64.3% patients showed tumour invasion sinuses (36/56), and that of 98.2% patients showed the tumour within sinuses or thick mucous membrane inside sinuses connecting with primary carcinoma, and having the same signal in strengthen scan. Therefore, they could be considered as a consecutive whole with the same character. This trait was propitious to diagnosis. There were 25% cases storing up fluid in sinuses, might be connected with the hatchs of sinuses walled up by tumour or inflammation. So, the most MRI characters of paranasal sinuses infringed were concluded: (1) The finding of sinuses wall was discontinuous; (2) Uneven thick mucous membrane in sinuses, and some storing up fluid in sinuses; (3) Tumour invasion sinuses cavity connective mass, and same enhancement signal in MR image (Fig. 1); (4) Presentation as equal signal or lower signal in T1W1 MRI scan, equal signal or higher signal in T2W1 and obvious enhancement in the enhanced MRI scan. In this study, the rate of clivus infringed was interrelated with the extent of sinuses infringed. In the team of early sinuses infringed cases, which only showed breakage in the wall or thick mucous membrane in sinuses, the rate of clivus infringed was 45% (9/20). In the team of single sinus infringed, the rate was 88% (22/25). And in the team of multiple sinuses infringed, the rate was 100% (11/11). The encroachment route for paranasal sinuses was

Discussion According to nasopharyngeal carcinoma “92 stage”, paranasal sinuses infringed was T4 stage, IV clinical stage. That implied prognosis worse [1]. MRI could distinguish

Fig.  1  Nasopharynx tumor intruded into sinus sphenoidalis by destroying the floor of sinus sphenoidalis

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Chinese-German J Clin Oncol, December 2009, Vol. 8, No. 12

Fig.  2  (a) It only showed the tumor inside the sinus ethmoidales in the horizontal section. (b) It showed the tumor intruded into sinus ethmoidales in the sagittal section

based mainly on the tumour extent and breakage in the wall of paranasal sinuses. The floor of sinus sphenoidalis bordered upon nasopharynx roof, and the front wall was near by sinus ethmoidales. The encroachment route was that primary tumour directly destroyed the floor of sinus sphenoidalis in most patients, the next route was the sinus ethmoidales invaded toward the front wall of sinus sphenoidalis. They showed only the floor of sinus sphenoidalis breakage (47/56), or the floor, back wall of sinus ethmoidales and the front wall of sinus sphenoidalis united breakage (5/56) in the MRI scans. The nasal cavity was under sinus ethmoidales. The posterior wall of sinus ethmoidales was near by the front wall of sinus sphenoidalis. So the invasive route of sinus ethmoidales was mostly by nasal cavity or sinus sphenoidalis encroached first, then sinus ethmoidales. In the MRI scans, they showed tumour broke into nasal cavity and destroyed the floor of sinus ethmoidales (5/56), or destroyed the floor, front wall of sinus sphenoidalis and back wall of sinus ethmoidales at the same time (4/56). The paper reported that tumour could break into sinus maxillaris first and then break into sinus ethmoidales [5]. The encroachment route of sinus maxillaris was by encroaching the nasal cavity or parapharynx space first and then destroying the wall of sinus maxillaris. In the MRI scans, they showed the wall of sinus maxillaris destroyed (7/56). The routes of paranasal sinuses were as same as those reported in papers [5]. Because the sinus sphenoidalis was next to the sinus ethmoidales, so when the tumor intruded into one sinus, the another sinus would be involved easily. When multiple sinuses were invaded, the prognosis would be worse to these patients [6]. In order to assess the tumour infiltration extent accurately, it is of extreme importance to recognize these features. On MRI scan technique, the positive rate of paranasal sinuses infringed was 98.2% in the sagittal section, and it was the highest. And that was 66.1% in the horizontal

section, and it was the lowest (P < 0.000). Looked back the missed cases in the horizontal section and coronal section were all the patients with sinus sphenoidalis infringed. And the early cases that only breakage in the floor of sinus sphenoidalis were more than anther cases in them (14/56 and 12/56). The misdiagnosis might be correlate with thickness of MRI scan. Because the width was longer than deepness in nasopharyngeal cavity, so the information about the floor of sinus sphenoidalis and the number of MRI scan in the sagittal section scan were more than those in coronal section scan. The sinus sphenoidalis was above the nasopharyngeal cavity, and we could observe nasopharyngeal tumor intruding into sinus sphenoidalis distinctly in the sagittal section scan. The sinus ethmoidales was forward and above the nasopharyngeal cavity, it was difficult to display the sinus ethmoidales and the nasopharyngeal cavity at a scan in the horizontal section or coronal section. So it was not ideal in estimating encroaching range of tumor in the horizontal section or coronal section. It could display the sinus ethmoidales and the nasopharyngeal cavity at a scan in the sagittal section, that we could observe nasopharyngeal tumor intruding into sinus ethmoidales easily (Fig. 2). On MRI list, the positive rate of paranasal sinuses infringed was 100% in strengthen scan, but that was nearly 60% in the T1W1 or T2W1. The T2W1 list was very important in distinguishing paranasal sinuses infringed and inflammation of sinuses. Because over 95% inflammation of sinuses showed higher signal, and over 95% tumor showed equal or high signal in the T2W1 list [4]. Thus it could be seen that to improve the positive rate of paranasal sinuses infringed, we must diagnose by multi-list of MRI scan and read carefully the MRI scan result.

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