Abstract
Objective
To evaluate the manubrium tracheal index (M-TI) at 3 levels and the correlation between M-TI and other conventional techniques.
Methods
Medical records and thoracic radiographs of healthy bulldogs were investigated. Tracheal luminal diameter (TLD) was measured at the caudal cervical, thoracic inlet, and intrathoracic tracheal regions on right lateral thoracic view. The absolute and average TLDs were standardized by the manubrium length (ML), thoracic inlet distance (Ti-D), and proximal third rib width to calculate M-TI, thoracic inlet tracheal index (Ti-TI), and proximal rib3 tracheal score (PR3-TS), respectively. Correlations between averaged tracheal diameter and each of ML, Ti-D, and proximal third rib width and between M-TI and each of Ti-TI and PR3-TS were evaluated.
Results
100 healthy French (n = 34), English (n = 33), and American (n = 33) Bulldogs met the inclusion criteria. The narrowest tracheal diameter was identified at the thoracic inlet, which was significantly narrower than both the caudal cervical and intrathoracic tracheal regions. There was no significant difference between the caudal cervical and intrathoracic tracheal regions. Strong, positive, linear correlations were identified between TLD and each normalizing parameter (ie, ML, Ti-D, and PR3-TS). Weak-to-moderate correlations were identified between the 3 procedures (ie, M-TI, Ti-TI, and PR3-TS).
Conclusions
M-TI could be an alternative to Ti-TI and PR3-TS for monitoring TLD in bulldogs. Therefore, future screening for tracheal hypoplasia is recommended using M-TI.
Clinical Relevance
Bulldogs with M-TI < 0.29 at the thoracic inlet trachea and < 0.33 at the caudal cervical and intrathoracic trachea (average M-TI < 0.32) may have tracheal hypoplasia. However, further assessments of diseased bulldogs and the repeatability of measurements are still warranted.
Tracheal hypoplasia is one of the common malformations contributing to brachycephalic airway syndrome in dogs.1–3 Respiratory distress secondary to canine congenital tracheal hypoplasia or acquired tracheal stenosis adversely impacts the quality of animal life and could be a life-threatening condition that needs immediate diagnosis and urgent intervention.4 Many radiographic and CT procedures have been established in dogs to determine the tracheal lumen and thus assess the hypoplastic trachea.2,5–10 Nevertheless, radiography remains the most widely available modality for veterinary practitioners worldwide to diagnose and monitor canine tracheal hypoplasia via calculating the corresponding tracheal lumen.8,11,12 Furthermore, quantitative radiographic evaluation of the tracheal lumen was reported to be beneficial in selecting the correct sizes of endotracheal tubes and tracheal stents for dogs with tracheal collapse.8 Quantitative assessment of tracheal diameter is commonly performed at the level of the thoracic inlet using the thoracic inlet distance (Ti-D)2,6,7,13,14 or the width of the proximal third rib (PR3-W)7,15 as references. However, the proximal widths of the rib3 pair were not always equal on lateral thoracic view due to the possibility of minimal dog tilting in lateral recumbency.2,6,16 In addition, using a too-small proximal rib3 width (PR3-W) was more susceptible to errors compared to the use of Ti-D.6 The overlapping of the third pair of ribs limited the measurement of the PR3-W, especially in bulldogs with crowded ribs secondary to foreshortened thoracic vertebrae (ie, thoracic vertebral anomaly [TVA]). Likewise, the Ti-D should be impacted by the existence of foreshortened thoracic vertebrae in bulldogs and the inconsistent landmarks described to measure it. Moreover, bulldogs with TVA may impact the thoracic inlet tracheal index (Ti-TI) and proximal rib3 tracheal score (PR3-TS) results as the Ti-D may appear relatively longer, and the associated thoracic inlet tracheal region is expected to be more caudal in those dogs. Therefore, these limitations are expected to bias the results associated with the PR3-TS and Ti-TI procedures in bulldogs. Recently, manubrium length (ML), which was proven to strongly correlate (rs ≥ 0.81) with the corresponding tracheal lumen, was utilized as a reference parameter to standardize the diameter of the tracheal lumen at 3 different levels along the trachea in nonbrachycephalic and nonbulldog brachycephalic breeds.17,18 This was named the manubrium tracheal index (M-TI).17,18 However, quantitative radiographic evaluation of the tracheal lumen using M-TI has not been determined along the tracheal segments in bulldogs, the most well-known dog breeds affected with tracheal hypoplasia. Therefore, this study aimed to calculate the M-TI for bulldogs and to determine whether or not the diameter of the trachea would vary with the region at which the tracheal lumen was measured (ie, caudal cervical, thoracic inlet, and intrathoracic regions). Our study also determined the correlation between the 3 radiographic procedures (ie, M-TI, Ti-TI, and PR3-TS). We hypothesized that the diameter of the tracheal lumen varies with the anatomic region of the tracheal segment in bulldogs. The second hypothesis was that M-TI can be used as an alternative procedure to objectively evaluate bulldogs’ tracheal luminal diameter (TLD) and as a screening diagnostic protocol for tracheal hypoplasia in these breeds.
Methods
Population
Veterinary records and thoracic radiographs were retrieved from the Small Animal Hospital in the College of Veterinary Medicine at the University of Florida for bulldogs (American, English, and French) admitted from May 2005 through December 2020. The study enrolled adult, client-owned bulldogs without clinical or radiographic evidence of tracheal, respiratory, or cardiovascular abnormalities. The dogs selected were those without respiratory manifestations (ie, stertorous breathing or exercise intolerance), heart murmurs, or gallops on auscultation, and their thoracic radiographs were within normal limits. All radiographs were presumed to be taken at peak inspiration without animal sedation or anesthesia. We excluded bulldogs with geriatric pulmonary, airway, and/or vascular changes (ie, fibrosis or mineralization/osteomas) as well as those with a history of oral, neck, or chest surgery. Also, subjects with clinical and/or radiographic evidence of thickened soft palate (ie, narrow nasopharynx with associated stridor), tracheal hypoplasia (ie, generalized narrowing of the tracheal lumen with associated respiratory distress), redundant dorsal tracheal membrane, esophageal abnormalities (such as esophageal foreign body or neoplasia, hiatal hernia, megaesophagus, or fluid-filled esophagus), or radiographic evidence of manubrium deformity (such as abnormally shaped, fused, or short manubrium)17 were excluded. The manubrium was interpreted as short if its length equaled or was shorter than the concomitant second sternal segment. The conformation of the manubrium was considered normal if it was elongated and either bullet, rectangular, or camel head/neck shaped.19,20 Thoracic vertebral anomaly was described as “mild” if there were one or few slightly wedge-shaped thoracic vertebrae without radiographic evidence of crowding of the ribs.
Ethical review and approval were not required for the study as the retrospective nature of the present study was based solely on reviews of medical records and radiographs generated during routine veterinary care of the subjects.
Radiographic measurements
A board-certified radiologist (CRB) evaluated the quality and positioning of the thoracic radiographs independently using standard exposure factors and focal spot-film distances. A digital radiography plate (CXDI-50G Digital Plate; Canon USA Inc) was utilized to obtain our radiographs, which were retrieved using an image-archiving communication system (Merge PACS; Merge Healthcare Inc). The right lateral view of the thorax was used, and all measurements were done by the same investigator (AAM) using the same image-archiving PACS system. Vertical TLD was measured at 3 levels (caudal cervical, thoracic inlet, and intrathoracic trachea) from dorsal to ventral mucosal surfaces. The 3 reported tracheal regions utilized to assess each corresponding TLD were selected and modified from previously established procedures.5,7–9,15,17,18,21 The caudal cervical TLD was measured at the level of mid-C5. The thoracic inlet TLD was measured at the level of the caudal C7. The intrathoracic TLD was measured at the mid-distance between the thoracic inlet and the caudal extent of the trachea, which is mostly identified between mid-T2 and mid-T3.17,18 To alleviate the differences in the TLD attributed to breed variation, the absolute and average TLDs were normalized by the ML, the Ti-D, and the PR3-W (Figure 1). The Ti-D was defined as the minimum Ti-D that extends from the cranioventral aspect of the T1 vertebra to the craniodorsal aspect of the manubrium at its most dorsal extent. The PR3-W was measured along the ventral margin of the body T3 vertebra, not at the junction between the dorsal one-third and the ventral two-thirds of rib3 as previously described.7,15 Standardization was then performed by calculating the M-TI (TLD:ML), Ti-TI (TLD:Ti-D), and PR3-TS (TLD:PR3-W) for each tracheal region.
Right (R) lateral thoracic radiograph of a clinically normal American Bulldog illustrating measurements of the absolute tracheal luminal diameters (TLDs) at the caudal cervical, thoracic inlet, and intrathoracic tracheal regions and measurements of manubrium length (ML), thoracic inlet distance (Ti-D), and proximal third rib width (PR3-W) for determination of manubrium tracheal index (M-TI) and thoracic inlet tracheal index (Ti-TI) and proximal rib3 tracheal score (PR3-TS). MB = Initails of technician who took the radiographs.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0400
Statistical analysis
According to the central limit theorem, parametric tests were employed to analyze our presumed normally distributed variables.22 Furthermore, data were tested for normality using the D’Agostino and Pearson test and were proven to be normally distributed. Means (± SDs) and 95% CIs were calculated for the variables. Multiple comparisons were carried out using ANOVA, the Tukey test, and unpaired 2-tailed t tests. An absolute significance level of less than 0.05 was used for statistical analysis. The Spearman correlation coefficient was calculated to determine the correlation between the average TLD and each of the ML, Ti-D, and PR3-W. Similarly, the correlation between M-TI and each of Ti-TI and PR3-TS was evaluated. Linear regression analysis was also performed to determine the influence of body weight and age on selected variables. Data were analyzed using GraphPad Prism (version 8.0.0 for Windows; GraphPad Software Inc).
Results
Population
Medical records and thoracic radiographs of 118 bulldogs were reviewed. Eighteen (15.3%) were excluded due to the existence of accompanying short (15 dogs [12.7%]) and fused (3 dogs [2.5%]) manubriums. The investigated 100 bulldogs (34 French, 33 English, and 33 American Bulldogs) met the criteria for inclusion and were admitted to our clinic for reasons other than respiratory or cardiovascular diseases, mostly for routine assessment of pulmonary metastasis with no clinical or radiographic evidence of abnormalities. Among the 100 dogs were 34 French Bulldogs, 33 English Bulldogs, and 33 American Bulldogs. The mean (± SD) age and body weight were 5.8 (± 2.9; range, 0.8 to 11.8) years and 23.3 (± 11.2; range, 6.6 to 57.1) kg, respectively. There were 54 males (36 castrated) and 46 females (37 spayed), with a male-to-female ratio of approximately 1.2:1. Thoracic vertebral anomaly (TVA) was identified in 20 English Bulldogs (5 dogs had mild TVA), 17 French Bulldogs (9 dogs had mild TVA), and 1 American Bulldog showed mild TVA.
Radiographic measurements
The smallest TLDs were identified at the thoracic inlet, and these measurements were significantly smaller than the caudal cervical (P = .006) and intrathoracic (P = .005) regions. There was no difference between the caudal cervical and intrathoracic TLDs (P ≥ .175). The lowest mean TLD was determined at the level of the thoracic inlet (Figure 2; Table 1). The mean absolute TLD calculated at the level of the thoracic inlet (11.4 mm) was approximately 11.6% and 10.9% lower than those calculated at the caudal cervical (12.9 mm) and intrathoracic (12.8 mm) trachea, respectively.
Box-and-whisker plots of the tracheal diameter (A), M-TI (B), Ti-TI (C), and PR3-TS (D) at the caudal cervical, thoracic inlet, and intrathoracic tracheal regions for 100 bulldogs with no clinical or radiographic evidence of respiratory or cardiovascular diseases. Boxes and whiskers represent the 25th to 75th percentiles and ranges, respectively; the lines and crosses within boxes represent the medians and means, respectively.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0400
Mean (± SD) values and 95% CIs for radiographic measurements of the absolute, average, and normalized values of tracheal luminal diameter (TLD) at caudal cervical (A; mid-C5), thoracic inlet (B; Ca-C7), and intrathoracic (C; mid–T2-T3) tracheal regions for 100 “healthy” French (n = 34), English (n = 33), and American (n = 33) Bulldogs.
| Variables | Mean ± SD | 95% CI | P < .05 | ||
|---|---|---|---|---|---|
| Absolute TLD (mm) | ANOVA test | Tukey test | Unpaired t test | ||
| A: Caudal cervical TLD (mid-C5) | 12.9 ± 3.7 | 12.1–13.7 | A–B, P = .017 | A–B, P = .006 | |
| B: Thoracic inlet TLD (Ca-C7) | 11.4 ± 3.3 | 10.8–12.1 | P = .006 | A–C, P = .994 | A–C, P = .922 |
| C: Intrathoracic TLD (mid–T2-T3) | 12.8 ± 3.5 | 12.1–13.5 | B–C, P = .016 | B–C, P = .005 | |
| Average TLD | 12.2 ± 3.3 | 11.5–12.9 | |||
| Normalizing parameter (mm) | |||||
| Manubrium length | 38.2 ± 9.6 | 36.4–40.1 | |||
| Thoracic inlet distance | 69.4 ± 13.7 | 66.7–72.1 | |||
| Proximal rib3 width | 4.7 ± 1.7 | 4.4–5.1 | |||
| M-TI | |||||
| A: M-TI (caudal cervical trachea) | 0.35 ± 0.06 | 0.33–0.36 | A–B, P < .0001 | A–B, P < .0001 | |
| B: M-TI (thoracic inlet trachea) | 0.30 ± 0.05 | 0.29–0.31 | A–C, P = .547 | A–C, P = .307 | |
| C: M-TI (intrathoracic trachea) | 0.34 ± 0.05 | 0.33–0.35 | B–C, P < .0001 | B–C, P < .0001 | |
| Average M-TI | 0.33 ± 0.05 | 0.32–0.34 | |||
| Ti-TI | |||||
| A: Ti-TI (caudal cervical trachea) | 0.19 ± 0.04 | 0.18–0.20 | A–B, P < .0001 | A–B, P < .0001 | |
| B: Ti-TI (thoracic inlet trachea) | 0.16 ± 0.03 | 0.16–0.17 | A–C, P = .696 | A–C, P = .436 | |
| C: Ti-TI (intrathoracic trachea) | 0.18 ± 0.03 | 0.18–0.19 | P < .0001 | B–C, P < .0001 | B–C, P < .0001 |
| Average Ti-TI | 0.18 ± 0.03 | 0.17–0.18 | |||
| PR3-TS | |||||
| A: PR3-TS (caudal cervical trachea) | 3.0 ± 0.6 | 2.8–3.1 | A–B, P < .0001 | A–B, P < .0001 | |
| B: PR3-TS (thoracic inlet trachea) | 2.5 ± 0.6 | 2.4–2.7 | A–C, P = .337 | A–C, P = .175 | |
| C: PR3-TS (intrathoracic trachea) | 2.9 ± 0.6 | 2.7–3.0 | B–C, P = .0008 | B–C, P = .0002 | |
| Average PR3-TS | 2.8 ± 0.6 | 2.7–2.9 | |||
M-TI = Manubrium tracheal index. PR3-TS = Proximal rib3 tracheal score. Ti-TI = Thoracic inlet tracheal index.
The data showed a strong, positive, linear association between the average TLD and each of the ML (rs = 0.79; P < .0001), Ti-D (rs = 0.77; P < .0001), and PR3-W (rs = 0.80; P < .0001; Figure 3). Weak-to-moderate correlations were determined between the M-TI and each of the Ti-TI (rs = 0.52; P < .0001) and PR3-TS (rs = 0.40; P = .0002; Figure 4). There was no significant correlation (rs = 0.20; P = .06) identified between the Ti-TI and PR3-TS techniques (Figure 4). The body weight and age of the bulldogs did not strongly correlate with the standardized TLDs (ie, M-TI, Ti-TI, and PR3-TS; Figure 5).
Scatter plots of the average tracheal diameter versus ML (A), Ti-D (B), and PR3-W (C) determined for 100 bulldogs with no clinical or radiographic evidence of respiratory or cardiovascular diseases.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0400
Scatter plots of the average M-TI versus average Ti-TI (A) and average PR3-TS (B) and of the average Ti-TI versus average PR3-TS (C) determined for 100 bulldogs with no clinical or radiographic evidence of respiratory or cardiovascular diseases.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0400
Scatter plots of the body weight and age versus average M-TI (A and D), average Ti-TI (B and E), and average PR3-TS (C and F) determined for 100 bulldogs with no clinical or radiographic evidence of respiratory or cardiovascular diseases.
Citation: American Journal of Veterinary Research 2025; 10.2460/ajvr.24.12.0400
Discussion
The main findings of the present study were that (1) TLD was significantly smaller (slightly more than 10%) at the thoracic inlet than the caudal cervical and intrathoracic portions; (2) relatively similar correlations (rs ≥ 0.77) were identified between the average TLD and each of the ML, Ti-D, and proximal third rib width (PR3-W); and (3) the mean M-TI calculated at the caudal cervical, thoracic inlet, and intrathoracic tracheal regions was 0.35, 0.30, and 0.34, respectively.
Across a variety of studies,9,17,18,23 the thoracic inlet was consistently the smallest tracheal diameter in most dog breeds. In English Bulldogs, the thoracic inlet tracheal diameter was the narrowest on radiography, which was confirmed via CT and tracheoscopy.9 Our results match those that found that tracheal rings have the narrowest diameter and smallest thickness at the thoracic inlet.23 The change of the direction of the trachea at a relatively small and bony thoracic inlet and the dynamic compression of the esophagus on the trachea at this region alter the TLD, predisposing to thoracic inlet tracheal collapse.23–26 In 2 recent similar studies17,18 performed on nonbrachycephalic and nonbulldog brachycephalic breeds, the narrowest TLD was also identified at the level of the thoracic inlet. In nonbrachycephalic and nonbulldog brachycephalic breeds, thoracic inlet TLDs were 20.7% and 10.9% narrower than TLDs measured at the corresponding cervical and intrathoracic regions, respectively,17,18 compared to 11.6% and 10.9% calculated for our enrolled bulldogs. These percentages are greater than those calculated for large-breed dogs, where thoracic inlet TLD was only 5.7% narrower than that measured at the caudal cervical region and 7.6% narrower than that measured at the intrathoracic trachea region.23 Thus, the results of this study indicate that the tracheal lumen narrows mildly at the thoracic inlet, as seen in the right lateral radiograph, consistent with previous studies.17,18,23 Even though TLD measures 1.0 mm lower with radiography compared to CT,8 radiography is still the most available modality evaluating tracheal diameter in dogs.11,12 Radiographic evaluation of TLD was routinely standardized at the level of the thoracic inlet using either Ti-D to calculate Ti-TI or PR3-W to calculate PR3-TS.2,6,7,13–15 However, the limitations associated with the PR3-W and Ti-D measurements due to dog tilting2,6,16 and TVA are expected to bias the results of the PR3-TS and Ti-TI procedures in bulldogs. The current study measured the Ti-D and PR3-W in consistent approaches as described in the methodology; however, the mild TVA identified in 39% of our investigated bulldogs may still have impacted the results of both Ti-TI and PR3-TS procedures. In the 39% of bulldogs with mild TVA, the Ti-D appeared relatively longer, and the thoracic inlet tracheal region was more caudal than bulldogs without TVA. This may again have biased the results of the Ti-TI calculated at the 3 tracheal levels. As a result, the authors suggest that M-TI could serve as an alternative method for assessing TLD in bulldogs.
A relatively similar strong correlation coefficient was identified between the average TLD and the length of the corresponding ML in 3 groups of dog breeds (rs = 0.82 in nonbrachycephalic breeds17 and rs = 0.81 in nonbulldog brachycephalic18 vs rs = 0.79 in our investigated bulldogs). Furthermore, M-TI correlated better with Ti-TI (0.83 ≥ rs ≥ 0.52) compared to PR3-TS (0.63 ≥ rs ≥ 0.40) in the 3 groups of dogs. Therefore, our current and previous studies17,18 strongly recommend calculating the M-TIs at the caudal cervical, thoracic inlet, and intrathoracic tracheal levels as a simpler alternative measure to objectively evaluate the tracheal lumen in dogs. The means M-TI calculated at the cervical, thoracic inlet, and intrathoracic regions were relatively higher in nonbrachycephalic dogs (0.45, 0.35, and 0.39; average, 0.40)17 compared to those calculated for nonbulldog brachycephalic breeds (0.41, 0.32, and 0.35; average, 0.36)18 and our current investigated bulldogs (0.35, 0.30, and 0.34; average, 0.33), respectively. Similar to a previous report9 (rs = 0.23), no correlation was found in this study between Ti-TI and PR3-TS (rs = 0.20). Furthermore, both Ti-TI and PR3-TS revealed questionable diagnostic value due to their reported poor agreement, which has influenced their reliability.7 The previous reference values of Ti-TI calculated at the thoracic inlet were 0.11, 0.12, or 0.13 in bulldogs, 0.16 or 0.17 in nonbulldog brachycephalic, and 0.20 or 0.21 in nonbrachycephalic breeds.2,14,15,17,18,27 Hypoplasia was previously indicated by a Ti-TI value less than 0.09 for English Bulldogs and less than 0.13 for the other examined brachycephalic dogs (French Bulldog, Pug, Maltese, Cavalier King Charles Spaniel, Shih Tzu, and Pekingese).2,27 In our investigated bulldogs, a reference Ti-TI value calculated at the thoracic inlet below 0.16 may indicate tracheal hypoplasia. The minimal discrepancy in the Ti-TI values between our and previous reports may be due to the different landmarks employed in our study to measure the Ti-D as well as the relatively larger population of healthy bulldogs investigated here. Nevertheless, the present study remains in agreement with a previous report9 where the mean Ti-TI (0.16 ± 0.03) was relatively consistent with that (0.17 ± 0.03) calculated for 40 healthy English Bulldogs. Therefore, we would suggest the use of M-TI along with Ti-TI reference values to radiographically diagnose hypoplastic trachea in bulldogs. In this study, the PR3-TS of the intrathoracic trachea was established at 2.9, slightly lower than previously reported values for brachycephalic breeds (> 3.0)2,15,28,29 but well above proposed cutoffs for tracheal hypoplasia PR3-TS < 2.0.14,30 In another study,9 the mean PR3-TS calculated for 40 healthy English Bulldogs was 2.5. To the best of our knowledge, quantitative radiographic evaluation of the tracheal lumen at the caudal cervical region was not established in bulldogs using different normalizing parameters. Therefore, the M-TI, Ti-TI, and PR3-TS means (0.35, 0.19, and 3.0, respectively) were calculated at the caudal cervical trachea for the currently investigated bulldogs.
The present study remains limited by the lack of assessment of inter- and intraobserver variability of the M-TI procedure despite the ease of defining the landmarks of ML and TLD. Another limitation is the retrospective nature of the study, which did not allow for calculation of the sample size and evaluation of the cranial and midcervical tracheal lumen. The present study focused solely on healthy bulldogs; therefore, future validation studies should compare healthy and diseased bulldogs to establish diagnostic cutoffs. Although body weight did not influence the measurement of M-TI, it is still necessary to conduct another study to compare M-TI across bulldog breeds.
Tracheal luminal diameters measured along the trachea of bulldogs varied according to the location of the tracheal segment. The narrowest TLD was identified at the thoracic inlet tracheal region. Manubrium tracheal index could be an alternative to Ti-TI and PR3-TS for radiographic assessment of TLD in bulldogs. Bulldogs with M-TI < 0.29 at the thoracic inlet trachea and < 0.33 at the caudal cervical and intrathoracic trachea (average M-TI < 0.32) may have tracheal hypoplasia. An average M-TI, Ti-TI, or PR3-TS less than 0.32, 0.17, or 2.7, respectively, may indicate tracheal hypoplasia in bulldogs. A screening protocol (likely named TLD scheme) could be established in the future to assess the TLD at 3 different levels along the trachea of normal and dyspneic bulldogs. Nevertheless, future studies validating our reported radiographic measurements are still recommended via calculating their repeatability and assessing tracheal diameters in healthy versus dyspneic dogs.
Acknowledgments
The authors would like to acknowledge the technicians and personnel in radiology services for their assistance with data collection.
Disclosures
The authors have nothing to disclose. No AI-assisted technologies were used in the composition of this manuscript.
Funding
The authors have nothing to disclose.
ORCID
Ayman A. Mostafa https://orcid.org/0000-0001-5909-8581
Clifford R. Berry https://orcid.org/0000-0003-4682-8885
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