Limits...
Prevalence and imaging characteristics of detectable tonsilloliths on 482 pairs of consecutive CT and panoramic radiographs.

Oda M, Kito S, Tanaka T, Nishida I, Awano S, Fujita Y, Saeki K, Matsumoto-Takeda S, Wakasugi-Sato N, Habu M, Kokuryo S, Kodama M, Kaneuji T, Yoshiga D, Miyamoto I, Nishimura S, Yamashita Y, Maki K, Tominaga K, Yoshioka I, Ansai T, Morimoto Y - BMC Oral Health (2013)

Bottom Line: In addition, the causes in cases of disagreement between the two modalities were analyzed.As the subjects aged, the detection rate increased gradually.A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001).

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Oral and Maxillofacial Radiology, Kyushu Dental University, Kitakyushu, Japan. rad-mori@kyu-dent.ac.jp.

ABSTRACT

Background: Recent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs.

Methods: 482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed.

Results: The detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001). However, the detection rate of tonsilloliths was only 7.3% on panoramic radiographs. A significant correlation was observed between the detection rate of tonsilloliths on panoramic radiographs and CT number (Spearman r = 0.429), size, (Spearman r = 0.318), and number of tonsilloliths (Spearman r = 0.333).

Conclusion: The present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.

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Four kinds of tonsillolith shapes on CT images. A) A dot shape of tonsilloliths (arrowhead) is shown on axial CT images. B) A round shape of tonsilloliths (arrowhead) is shown on axial CT images. C) An oval shape of tonsilloliths (arrowhead) is shown on axial CT images. D) An irregular shape of tonsilloliths (arrowhead) is shown on axial CT images.
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Figure 2: Four kinds of tonsillolith shapes on CT images. A) A dot shape of tonsilloliths (arrowhead) is shown on axial CT images. B) A round shape of tonsilloliths (arrowhead) is shown on axial CT images. C) An oval shape of tonsilloliths (arrowhead) is shown on axial CT images. D) An irregular shape of tonsilloliths (arrowhead) is shown on axial CT images.

Mentions: Of the 482 individuals, 222 (46.1%) were judged to have tonsilloliths on CT scans (Table 1). The 222 patients with tonsilloliths on CT images consisted of 91 males and 131 females, and no difference by sex in the tonsillolith detection rate was seen. However, a significant correlation was found between age and the tonsillolith detection rate (Spearman r = 0.176, p < 0.0001). As the subjects aged, the detection rate increased gradually. In particular, a significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001), but the tonsillolith detection rate was relatively stable among the various groups (Table 2). Overall, 99 patients had one calculus, 37 had two, 27 had three, 21 had four, 12 had five, and so on (Table 3), up to a maximum of 28 (Figure 1). The shapes of tonsilloliths varied, including dot, round, oval, and irregular structures (Figure 2). Round or oval tonsilloliths with a long diameter under 2 mm were considered dots, while those with a long: short diameter ratio of under 3:2 were considered round, those with a long: short diameter ratio of over 3:2 were considered oval, and those with shapes that were neither round nor oval were considered irregular. The most common shape was the dot lump and/or lumps of structure(s) with high CT number(s) within the palatine tonsil on CT images. With respect to the sizes of the tonsilloliths, 59 were under 2 mm, 149 were over 2 mm and under 5 mm, 14 were over 5 mm and under 10 mm, and none were over 8 mm (Table 4). The most common length was from under 3 to 4 mm on CT images. On CT, 63 (13.1%) were on the right side, 78 (16.3%) were on the left side, and 81 (16.8%) were bilateral (Table 5); the rates were almost equal, with no significant difference observed (p = 0.194). Furthermore, 157 were under the soft palate, 95 were coincident with the soft palate, and 0 were over the soft palate. At the same time, 95 were in the medial half and the others were in the lateral half of the tonsil. The calcification levels of tonsilloliths on CT images were over 100 HU and under 300 HU in 95, over 300 HU and under 500 HU in 68, over 500 HU and under 1000 HU in 46, and over 1000 HU in 13 (Table 6).


Prevalence and imaging characteristics of detectable tonsilloliths on 482 pairs of consecutive CT and panoramic radiographs.

Oda M, Kito S, Tanaka T, Nishida I, Awano S, Fujita Y, Saeki K, Matsumoto-Takeda S, Wakasugi-Sato N, Habu M, Kokuryo S, Kodama M, Kaneuji T, Yoshiga D, Miyamoto I, Nishimura S, Yamashita Y, Maki K, Tominaga K, Yoshioka I, Ansai T, Morimoto Y - BMC Oral Health (2013)

Four kinds of tonsillolith shapes on CT images. A) A dot shape of tonsilloliths (arrowhead) is shown on axial CT images. B) A round shape of tonsilloliths (arrowhead) is shown on axial CT images. C) An oval shape of tonsilloliths (arrowhead) is shown on axial CT images. D) An irregular shape of tonsilloliths (arrowhead) is shown on axial CT images.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3852777&req=5

Figure 2: Four kinds of tonsillolith shapes on CT images. A) A dot shape of tonsilloliths (arrowhead) is shown on axial CT images. B) A round shape of tonsilloliths (arrowhead) is shown on axial CT images. C) An oval shape of tonsilloliths (arrowhead) is shown on axial CT images. D) An irregular shape of tonsilloliths (arrowhead) is shown on axial CT images.
Mentions: Of the 482 individuals, 222 (46.1%) were judged to have tonsilloliths on CT scans (Table 1). The 222 patients with tonsilloliths on CT images consisted of 91 males and 131 females, and no difference by sex in the tonsillolith detection rate was seen. However, a significant correlation was found between age and the tonsillolith detection rate (Spearman r = 0.176, p < 0.0001). As the subjects aged, the detection rate increased gradually. In particular, a significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001), but the tonsillolith detection rate was relatively stable among the various groups (Table 2). Overall, 99 patients had one calculus, 37 had two, 27 had three, 21 had four, 12 had five, and so on (Table 3), up to a maximum of 28 (Figure 1). The shapes of tonsilloliths varied, including dot, round, oval, and irregular structures (Figure 2). Round or oval tonsilloliths with a long diameter under 2 mm were considered dots, while those with a long: short diameter ratio of under 3:2 were considered round, those with a long: short diameter ratio of over 3:2 were considered oval, and those with shapes that were neither round nor oval were considered irregular. The most common shape was the dot lump and/or lumps of structure(s) with high CT number(s) within the palatine tonsil on CT images. With respect to the sizes of the tonsilloliths, 59 were under 2 mm, 149 were over 2 mm and under 5 mm, 14 were over 5 mm and under 10 mm, and none were over 8 mm (Table 4). The most common length was from under 3 to 4 mm on CT images. On CT, 63 (13.1%) were on the right side, 78 (16.3%) were on the left side, and 81 (16.8%) were bilateral (Table 5); the rates were almost equal, with no significant difference observed (p = 0.194). Furthermore, 157 were under the soft palate, 95 were coincident with the soft palate, and 0 were over the soft palate. At the same time, 95 were in the medial half and the others were in the lateral half of the tonsil. The calcification levels of tonsilloliths on CT images were over 100 HU and under 300 HU in 95, over 300 HU and under 500 HU in 68, over 500 HU and under 1000 HU in 46, and over 1000 HU in 13 (Table 6).

Bottom Line: In addition, the causes in cases of disagreement between the two modalities were analyzed.As the subjects aged, the detection rate increased gradually.A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001).

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Oral and Maxillofacial Radiology, Kyushu Dental University, Kitakyushu, Japan. rad-mori@kyu-dent.ac.jp.

ABSTRACT

Background: Recent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs.

Methods: 482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed.

Results: The detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001). However, the detection rate of tonsilloliths was only 7.3% on panoramic radiographs. A significant correlation was observed between the detection rate of tonsilloliths on panoramic radiographs and CT number (Spearman r = 0.429), size, (Spearman r = 0.318), and number of tonsilloliths (Spearman r = 0.333).

Conclusion: The present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.

Show MeSH
Related in: MedlinePlus