Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2797_Библиотеки_им_академика_М_И_Перельмана
.pdf
62 Textbook of Diagnostic and Therapeutic Procedures in Allergy
https://t.me/medicina_free
(A)
(B)
(C) (D)
Figure 3. Anterior drainage pathway. (A) The middle meatus is the air space lateral and inferior to the middle turbinate,
indicated by white arrows. (B) The maxillary sinus drains into the middle meatus via the infundibulum (hatched arrow) which
leads to the hiatus semilunaris at the superior aspect of the uncinate process (solid arrow). (C) The frontal sinus drains via
the frontoethmoidal recess (arrow). (D) The anterior ethmoid sinuses each drain directly into the middle meatus (arrows).
Figure 4. Common normal variants in the nasal cavity and paranasal sinuses. (A) A Haller air cell (arrow) is an ethmoid air
cell that lies within the maxillary sinus bordering the orbital floor. (B) An Onodi air cell (solid arrow) is an ethmoid air cell
that lies superior to the sphenoid sinus, bordering on the optic canal (dashed arrow). (C) A pneumatized middle turbinate is
called a concha bullosa, seen here bilaterally (arrows). (D) Nasal septal deviations are very common variants. In this case,
there is a rightward nasal septal deviation with a large nasal septal spur (arrow).
(A)
(B)
(C) (D)
Sinus Imaging for Patients with Allergy and Asthma 63
https://t.me/medicina_free
to recognize because many of them are associated with increased complications during Functional
Endoscopic Sinus Surgery (FESS) (Shpilberg et al. 2015).
Findings of Sinonasal Inflammation
Though the sinuses are lined by mucosa, the normal non-inflamed mucosa is so thin it is not
visualized on CT and the sinuses typically appear to have a bone-air interface at their walls
(Figure 5A). Patients with chronic rhinosinusitis will tend to have opacified sinuses. There may be
circumferential mucosal thickening (Figure 5B), or a more focal rounded soft tissue density known
as a mucous retention cyst (Figure 5C). Air-fluid levels may be recognized by the presence of a
dependent meniscus on the axial images (Figure 6). Although air-fluid levels can be seen with acute
sinusitis, CSF (in the setting of a leak), and hemorrhage (particularly due to orbital floor fracture)
can also result in air-fluid levels.
The density of material in the paranasal sinuses can vary significantly according to the
concentration of protein in the sinonasal secretions. Watery secretions will be isodense to muscle
on CT (Figure 7A). As mucous becomes thicker and more inspissated, the density will increase
(Figure 7B). Ultimately secretions can harden into concretions which may become calcified.
Calcification in an opacified sinus may herald the presence of a fungus ball (Ng et al. 2015)
(Figure 8).
When a sinus becomes completely obstructed, secretions may continue to accumulate causing
pressure to increase within the sinus cavity. This pressure results in the expansion of the sinus with
smooth bony erosion of the walls. The expanded sinus is referred to as a mucocele and may exert a
mass effect on adjacent structures (Figure 9).
Figure 5. Patterns of opacification of the paranasal sinuses. (A) Axial and coronal images of normal maxillary sinuses.
The normal mucosa is imperceptibly thin and there is a bone-air interface at the sinus margins. (B) In this patient there is
moderate opacification of the right maxillary sinus but some aeration persists in the center. The left maxillary sinus is nearly
completely opacified. (C) Sinus opacification may be more focal as in this case where there is a retention cyst in the left
(A)
(B)
(C)
maxillary sinus (arrow).
64 Textbook of Diagnostic and Therapeutic Procedures in Allergy
https://t.me/medicina_free
Figure 6. Air-fluid level. In this image, there is mild circumferential mucosal thickening in the bilateral maxillary sinuses.
There is also fluid, recognized by the curved meniscus which indicates an air-fluid level (arrows). While air-fluid levels can
be associated with acute sinusitis, they are also seen in hemorrhage and CSF leaks.
(A)
Figure 7. Differences in attenuation. Sinus secretions may be watery or more proteinaceous. In both (A) and (B), the sinuses
are severely opacified; but on soft tissue windows, the opacification in A is isodense to the extraocular muscles in the orbit,
whereas in B the secretions are very hyperdense compared with the extraocular muscles.
Figure 8. Coronal images through the paranasal sinuses in soft tissue windows show a severely opacified maxillary sinus
with curvilinear calcification within it. Calcification within an opacified sinus is more common in patients with fungus balls
and this patient was found to have a fungus ball at the surgery.
(B)
CT may also demonstrate opacification of the nasal cavity, particularly in patients with nasal
polyposis. Nasal polyps appear as soft tissue lobulations within the sinus cavity (Figure 10A). If
there are numerous nasal polyps the entire nasal cavity may be opacified (Figure 10B).
History and clinical exams are essential components of accurate diagnosis of inflammatory
chronic rhinosinusitis. However, certain imaging patterns can be associated with particular etiologies
of chronic rhinosinusitis and can guide the differential. For example, diffuse polyposis with severe
Sinus Imaging for Patients with Allergy and Asthma 65
https://t.me/medicina_free
Figure 9. A patient with the severe sinonasal disease and multiple mucoceles. Coronal bone and soft tissue windows
demonstrate complete opacification of the nasal cavity and paranasal sinuses by a combination of polypoid soft tissue and
hyperdense secretions. There is a smooth bony expansion of ethmoid sinus walls bilaterally (solid arrows). There is a smooth
bony expansion of a left supraorbital air cell which is also filled with hyperdense secretions (dashed arrows). This is a typical
appearance of allergic fungal rhinosinusitis.
(A)
Figure 10. Nasal polyps. (A) Axial and coronal images through the paranasal sinuses demonstrate lobulated foci of soft
tissue (arrows) medial to the turbinates in this patient with nasal polyposis. (B) In this patient with more severe disease, axial
soft tissue and coronal bone windows show severe obstruction of the nasal cavity by polyps.
Figure 11. Allergic polyposis. Axial and coronal soft tissue images demonstrate severe opacification of the bilateral nasal
cavity, ethmoid sinuses and maxillary sinuses. There are hyperdense secretions filling the maxillary and ethmoid sinuses. At
surgery, the patient had thick allergic mucin but there was no evidence of fungal elements in pathology.
(B)
pan-sinus opacification can be seen in both NSAID-associated nasal polyposis and allergic fungal
rhinosinusitis. Additional findings may include increased density of the sinonasal secretions,
bilateral involvement and sinus expansion (Aribandi et al. 2007) (Figure 11). Inflammatory change
which predilects the nasal cavity may be seen in Central Compartment Atopic Disease. In CCAD,
even opacification of the sinuses has a more central pattern as it tends to occur along the medial
walls and floors of the involved sinuses (Roland et al. 2020). CT has poorer contrast resolution than
MRI when evaluating soft tissues. For this reason, MRI is an important addition to CT for tumor
evaluation and for evaluation of intracranial complications of sinusitis. In addition, many times
patients will have had MRIs, which include the paranasal sinuses for other indications (these are
most commonly brain MRIs). It is important to recognize that sinonasal opacification in MRIs done
66 Textbook of Diagnostic and Therapeutic Procedures in Allergy
https://t.me/medicina_free
for non-sinus indications may reveal clinically unimportant asymptomatic disease (Wani et al. 2001).
Nevertheless, for patients with chronic rhinosinusitis who have had MRI imaging, recognition of the
typical features of inflammatory disease is helpful.
Characteristics of Sinus Opacification on T1 and T2 Weighted Images
On T1 weighted images free water is relatively hypointense (to muscle). On T2 weighted images,
free water is hyperintense. Similarly, watery sinus secretions tend to be low in signal on T1-weighted
images and high in signal on T2-weighted images (Figure 12). However, sinus secretions vary in
their water content with chronic secretions becoming more inspissated over time. As the secretions
become less watery and more proteinaceous, the signal intensity increases on T1-weighted images
and can be bright on T1-weighted imaging (Figure 13). As sinus secretions begin to desiccate, signal
intensity declines until it is low on both T1 and T2 weighted images. This occurs at approximately
a 40% protein concentration (Som et al. 1989).
In addition, the presence of fungal elements may alter the paramagnetic qualities of the sinus
secretions. Because of their metabolism, fungi may accumulate iron and manganese in their local
environment, resulting in significant loss of signal due to paramagnetic effects (Zinreich et al.
1989). Patients with fungal sinusitis, either allergic fungal rhinosinusitis or fungus ball, may have
secretions that are so hypointense, they mimic a partially aerated sinus even when totally opacified
(Figure 14).
In addition to air, fungal disease and desiccated secretions, acute hemorrhage and bone or enamel
may also result in signal dropout on MRI imaging (Som et al. 1990). Therefore, interpretation of an
MRI of the sinuses should be performed with caution and typically a review of a contemporaneous
CT is helpful for accurate characterization.
Figure 12. MRI of watery secretions. T1 (left) and T2 (right) weighted images through the sphenoid sinus demonstrate
layering fluid with a meniscus (arrow). On the T1 weighted images, the fluid is relatively hypointense. On the T2 weighted
images, the fluid is hyperintense. This is typical of watery secretions with low protein content.
Figure 13. MRI of proteinaceous secretions. T1 (left) and T2 (right) weighted images demonstrate a right ethmoid mucocele
with proteinaceous secretions. No contrast was given (note that the nasal mucosa is dark gray and unenhanced) yet the
contents of this ethmoid mucocele are hyperintense on T1 weighted imaging. As the protein content of sinus secretions
increase, signal intensity increases on T1-weighted imaging until the secretions become densely inspissated.
Sinus Imaging for Patients with Allergy and Asthma 67
https://t.me/medicina_free
Figure 14. CT and MRI in a patient with AFRS. CT through the sphenoid sinuses clearly demonstrates completely opacified
sphenoid sinuses bilaterally with bone thinning posteriorly suggesting mucocele formation. On both T2 weighted images
(center image) and post-contrast T1 weighted images (right image), there is a complete signal dropout in these same sinuses
with the sinuses almost appearing aerated. This can be seen in fungal sinusitis and is thought to be caused not only by the
high protein content of the thick allergic mucin but also by increased concentrations of iron and manganese as a result of
fungal metabolism.
Magnetic Resonance Imaging
Characterization of Sinus Enhancement in Benign and Malignant Sinus Disease
After the administration of gadolinium, the intravenous contrast material used for MRI, the highly
vascular nasal and paranasal sinus mucosa markedly enhance. A few typical patterns of enhancement
are seen in the benign sinonasal disease. There is an avid enhancement of mild mucosal thickening.
There can also be polypoid mucosal thickening in the sinuses. In this case, a thin rim of mucosal
enhancement may be seen as superficial to more non-enhancing submucosal edema (Figure 15).
In contrast, sinonasal tumors have a more solid pattern of enhancement. Inverted papillomas
demonstrate what is termed a cerebriform appearance of enhancement with a heterogeneous
enhancement pattern, which has an appearance resembling the gyri and sulci of the brain (Ojiri et al.
2000) (Figure 16). Most malignant tumors enhance to a lesser degree than the adjacent mucosa and
can demonstrate the destruction of bony borders and extension outside of the sinus walls (Figure 17)
(Agarwal and Policeni 2019).
While an MRI of the sinuses is often performed for evaluation of malignancy, MRI can also
be useful for the identification of intracranial complications of benign sinus disease, such as dural
inflammation and empyema (Pulickal et al. 2018) (Figure 18).
Figure 15. MRI of benign mucosal thickening in the maxillary sinus. T2 weighted image demonstrates T2 hyperintense
lobulated thickening in the left maxillary sinus. On post-contrast imaging, we see two different patterns of benign
enhancement; along the roof and medial wall of the maxillary sinus, there is an avid enhancement of slightly thickened
mucosa (solid arrow). Along the floor of the left maxillary sinus, there is enhancing linear mucosa stretched over non-
enhancing submucosal edema (dashed arrow).
68 Textbook of Diagnostic and Therapeutic Procedures in Allergy
https://t.me/medicina_free
Figure 16. Contrast-enhanced MRI in the axial plane in a patient with an inverted papilloma which involves both the
nasal cavity and nasopharynx. Unlike the benign thin linear enhancement surrounding submucosal edema seen in the right
maxillary sinus (curved arrow), the inverted papilloma demonstrates heterogeneous solid enhancement (straight arrow) in a
pattern reminiscent of the gyri and sulci of the brain, termed “cerebriform.”
Figure 17. Sinonasal squamous cell carcinoma. Fat-saturated, contrast-enhanced MRI of the sinuses demonstrates a large
heterogeneously enhancing, destructive mass in the right maxillary sinus (arrows). Notice how the enhancement is less
intense than the benign sinus disease in the left maxillary sinus and sphenoid sinuses. Notice also that the tumor has extended
beyond the walls of the maxillary sinus into the premaxillary soft tissues, indicative of the aggressive nature of this tumor.
Figure 18. Axial CT and contrast-enhanced T1 weighted MRI images through the frontal sinuses both demonstrate
a left frontal mucocele; however, only the MRI also demonstrates the associated dural enhancement (arrow) in the
intracranial compartment.
Summary
Both CT and MRI can display abnormalities in patients with chronic sinusitis. Findings can be
variable depending on the density of the secretions in the sinuses. CT allows for the best delineation
of bony borders and thick proteinaceous secretions. MRI is superior to CT for tumor characterization
and evaluation of intracranial complications of sinusitis such as dural thickening or empyema.
Sinus Imaging for Patients with Allergy and Asthma 69
https://t.me/medicina_free
Glossary of Abbreviations
CT – Computed Tomography
MRI – Magnetic Resonance Imaging
References
Agarwal, M. and Policeni, B. 2019. Sinonasal neoplasms. Seminars in Roentgenology 54: 244–257.
Aribandi, M., McCoy, V. A. and Bazan, C. 3rd. 2007. Imaging features of invasive and noninvasive fungal sinusitis:
a review. Radiographics 27: 1283–96.
Ng, T. Y., Wang, J. Y., Tsai, M. H., Lin, C. C., Tai, C. J. and Ng, Y. K. 2015. Hyperdense findings in sinus computed
tomography of chronic rhinosinusitis. Int. Forum Allergy Rhinol. 5: 1181–4.
Ojiri, H., Ujita, M., Tada, S. and Fukuda, K. 2000. Potentially distinctive features of sinonasal inverted papilloma on
MR imaging. AJR Am. J. Roentgenol. 175: 465–8.
Pulickal, G. G., Navaratnam, A. V., Nguyen, T., Dragan, A. D., Dziedzic, M. and Lingam, R. K. 2018. Imaging
sinonasal disease with MRI: providing insight over and above CT. European Journal of Radiology 102: 157–168.
Roland, L. T., Marcus, S., Schertzer, J. S., Wise, S. K., Levy, J. M. and DelGaudio, J. M. 2020. Computed Tomography
findings can help identify different chronic rhinosinusitis with nasal polyp phenotypes. American Journal of
Rhinology & Allergy 34: 679–685.
Sahay, S., Gera, K., Bhargava, S. K. and Shah, A. 2016. Occurrence and impact of sinusitis in patients with asthma
and/or allergic rhinitis. J. Asthma 53: 635–43.
Shpilberg, K. A., Daniel, S. C., Doshi, A. H., Lawson, W. and Som, P. M. 2015. CT of anatomic variants of the
paranasal sinuses and nasal cavity: poor correlation with radiologically significant rhinosinusitis but importance
in surgical planning. AJR American Journal of Roentgenology 204: 1255–1260.
Som, P. M., Dillon, W. P., Fullerton, G. D., Zimmerman, R. A., Rajagopalan, B. and Marom, Z. 1989, Chronically
obstructed sinonasal secretions: observations on T1 and T2 shortening. Radiology 172: 515–20.
Som, P. M., Dillon, W. P., Curtin, H. D., Fullerton, G. D. and Lidov, M. 1990. Hypointense paranasal sinus foci:
differential diagnosis with MR imaging and relation to CT findings. Radiology 176: 777–81.
Wani, M. K., Ruckenstein, M. J. and Parikh, S. 2001. Magnetic resonance imaging of the paranasal sinuses: incidental
abnormalities and their relationship to patient symptoms. J. Otolaryngol. 30: 257–62.
Zinreich, S. J., Kennedy, D. W., Malat, J., Curtin, H. D., Epstein, J. I., Huff, L. C. et al. 1988. Fungal sinusitis:
diagnosis with CT and MR imaging. Radiology 169: 439–44.
Chapter 3D
https://t.me/medicina_free
Endoscopic Examination of the
Upper Airway
Jerald W. Koepke1,* and William K. Dolen2,*
Introduction
In patients presenting with upper airway complaints, the routine examination usually consists
of inspection of the anterior nares with an otoscope or nasal speculum and examination of the
pharynx with a tongue depressor. The otoscope permits only limited examination of the proximal
structures. Such an examination might suffice in patients with uncomplicated chronic rhinitis but
will not identify underlying anatomic variants or structural pathology in children or adults that
might complicate chronic rhinitis, allergic or nonallergic. The flexible fiberoptic rhinoscope
(Figure 1) makes upper airway examination a simple and convenient procedure, permitting
comprehensive evaluation of the upper airway. The performance of fiberoptic rhinolaryngoscopy
requires a basic understanding of relevant anatomy, physiology and pathology and relatively
frequent use of the endoscope.
1
Colorado Allergy and Asthma Centers, Denver, Colorado.
2
Allergy-Immunology and Pediatric Rheumatology Division, Departments of Pediatrics and Medicine, Medical College of
Georgia at Augusta University, Augusta, Georgia 30912.
* Corresponding authors: jwkmlk@gmail.com; bdolen@augusta.edu
Figure 1. The Olympus ENF-P3 rhinolaryngoscope.
Endoscopic Examination of the Upper Airway 71
https://t.me/medicina_free
An Overview of Normal Upper Airway Anatomy
The upper airway may be divided into regions (Figure 2). In adults, the nasal cavity is a channel
approximately 9 to 10 cm in length from the meatus to the posterior choana. The posterior choana
separates the nasal cavity from the nasopharynx. The oropharynx, in which the palatine tonsils are
located, extends from the inferior margin of the soft palate to the upper edge of the epiglottis. The
hypopharynx is located posterior to the aperture of the larynx. The triangular inlet of the larynx
(aditus laryngis) is formed by the superior margin of the epiglottis, the aryepiglottic folds and the
arytenoid cartilages. The larynx becomes continuous with the trachea.
Figure 2. The anatomic divisions of the upper airway; all five divisions may be inspected with a fiberoptic endoscope.
Anterior Nasal Structures
The septum divides the nasal cavity into the right and left chambers. The nasal vestibule is the most
anterior and inferior portion of the nasal cavity (Figure 3). It is bounded medially and laterally by the
alar cartilages and extends to the inferior border of the lateral nasal cartilage. Above the vestibule and
in front of the middle meatus is the nasal atrium, and above this is the agger nasi, a prominence that
generally contains anterior ethmoid air cells. The nasal floor is formed anteriorly by the maxillary
bone and posteriorly by the palatine bone. It is slightly concave and passes horizontally from the
vestibule to the choana. The nasal vault narrows superiorly to form the roof of the nose.
Nasal Septum
The nasal septum, rarely straight in normal adults, consists of both cartilaginous and bony components
(Figure 4), with mucous membrane overlying the perichondrium or periosteum of the underlying
cartilage or bone. The mobile, anterior portion of the septum, is composed of a quadrangular septal
cartilage resting in a groove on the maxillary bone and articulating posteriorly with the thin, delicate
bone of the perpendicular plate of the ethmoid and inferiorly with the thicker, more rigid bone of
the vomer. The vomer forms the medial border of the choanae and rests on the crest of the maxillary
Соседние файлы в папке Библиотека им академика М.И. Перельмана