Work in progress: NMR anatomy of the larynx and tongue base

Sonographic Staging of Cancer of the Mobile Tongue

In order to determine the value of sonography (US), in staging cancer of the mobile tongue, 57 patients were studied prospectively. Real-time sector scanners (5 and 7.5 MHz) were used with a submental approach. The findings by US were compared with those obtained by inspection and palpation and in 13 operated patients with the surgical results. US failed to visualize the tumor in 3 of the 57 patients (5%); in 30 patients (53%), the tumor was considered to be of nearly the same size by US and by palpation, but in 17 cases (30%), to be larger by US than by palpation, and in the remaining 7 cases (12%), to be smaller by US. Extension across the midline (8/8), and depth of tumor penetration, or extension to adjacent structures (5/5) were more correctly evaluated by US. We conclude that US is useful for staging work-up of tumors of the mobile tongue.

Neurologisch bedingte und neuromuskuläre Funktionsstörungen des Pharynx und Ösophagus

Neurologic swallowing disorders are an increasing diagnostic problem in our overaged population. Undiagnosed chronic aspiration pneumonia is the cause of death in 20-40% of all inhabitants of nursing homes. In neurologic diseases of the pharynx, the physiologic interaction of pharyngeal contraction, closure of the pharynx, and esophageal motility are frequently disturbed. This may be due to cortical, bulbar, or cerebellar brain damage of ischemic or traumatic origin. Furthermore diseases or peripheral nerves, muscles, and synapses cause disturbances. The most life-threatening complication of these disturbances is tracheal aspiration, which requires an iso-osmolar contrast medium for imaging studies that cause no or minimal pulmonary problems. Utilizing fast dynamic documentation we can analyze the swallowing act in 35 images within the passage time of 0.7 s. This requires digital frame sequences from 15-50 images/s, which can be provided by DSI or videofluoroscopy. Neurologic and neuromuscular patterns are demonstrated with and without tracheal aspiration. The differentiation of aspiration in a so-called pre-, intra-, and postdeglutitive form is possible. We distinguish four grades of severity of aspiration, which is also of great clinical impact for the differential rehabilitation therapy. The efficiency of the rehabilitation protocol can be assessed by the dynamic swallowing studies.

[Volumetry of the human tongue by MRI]

AIM

The purpose of this study was to determine the volume of the tongue using MRI. The correlation of the individual volume of the tongue and the size of the oral cavity was to be investigated.

MATERIAL AND METHODS

To analyze the tongue volume we combined coronal and sagittal data acquisition, which divided the tongue virtually into two lateral and one medial part. This procedure helped to decrease artefacts by partial volume effect. In 20 probands (m/f 7/13, average age of 36.3 years) the volume of the tongue was determined. Imaging protocol: Magnetom 63 SP (Siemens, Erlangen), T1-weighted sequences (TR/TE 500 ms/10 ms), slice thickness 5 mm, matrix 256 x 256, FOV 250 mm.

RESULTS

There was a significant linear regression between the tongue volume and height of the mouth cavity. This correlation can be used to calculate the normal volume of a patient's tongue.

DISCUSSION

Volumetry of the tongue can be carried out by means of MRI without application of injurious X-rays. It can be employed before as well as after tongue reduction surgeries for therapy control. The individual ideal tongue volume can be determined easily by determination of the height of the oral cavity.

O espaço sublingual

O espaço sublingual é um espaço de forma semilunar situado no soalho da boca. Estende-se desde a superfície interna da margem alveolar até a base da língua. Localiza-se medialmente ao músculo milo-hióideo, que o separa dos espaços submentoniano e submandibular,anteriormente ao complexo hioglosso-estiloglosso e lateralmente ao músculo genioglosso. A presença de tecido conjuntivo frouxo e tecido gorduroso como conteúdo neste espaço confere aspecto característico na tomografia computadorizada e na ressonância magnética, permitindo sua fácil identificação. Contém ainda a glândula sublingual, a porção profunda da glândula submandibular e seu ducto, a artéria e veia lingual, além dos nervos lingual, glossofaríngeo e hipoglosso. Suas relações são de grande importância, uma vez que lesões originadas na orofaringe e na cavidade oral podem envolver esta área. Os autores analisam a anatomia deste espaço e suas estruturas componentes, relacionando-as com enfermidades que o acometem. Os métodos de imagem são úteis na avaliação e compreensão dessas lesões, podendo também orientar condutas terapêuticas.

Magnetic resonance imaging and computed tomography in pediatric head and neck masses

Fifty-three magnetic resonance imaging (MRI) and 25 computed tomography (CT) studies of 53 head and neck masses in pediatric patients were reviewed retrospectively. All lesions had pathologic proof except for 2 metastatic and 2 recurrent lesions, which only had prior pathologic confirmation at their primary sites. These included 12 malignant tumors, 23 benign tumors, 6 inflammatory masses, and 12 congenital lesions. The MRI performance ranged predominantly from good to excellent in detection of the lesion and the extent of involvement and in contrast to the surrounding tissue; when CT comparison was available, MRI proved to be equal to or better than it in detection of these factors and in preoperative diagnosis. Our results suggest that MRI should be the method of choice for the initial evaluation of the pediatric head and neck region, especially in those patients requiring multiple examinations. However, CT and MRI should be used conjunctively in complicated cases, especially those possibly involving lesions with calcifications or bony involvement.

The use of MRI in the identification of post-traumatic laryngeal deformities

Suspected post-traumatic deformity of the laryngeal cartilages can be diagnosed by using current magnetic resonance imaging (MRI) scanning techniques. This is of particular aid to the clinician who is evaluating a laryngeal mass with no history of injury to the neck. Computed tomography (CT) and magnetic resonance imaging are both effective in this situation, but MRI appreciates better soft tissue contrast, and can offer coronal and sagittal views.

Glottic dimensions in healthy men and women

Glottic aperture is important in modulating respiratory system resistance. Male patients with obstructive sleep apnea (OSA) have a smaller glottic cross-sectional area compared to controls. Since OSA has a strong male predominance, we reasoned that glottic dimensions may differ between healthy men and women. Therefore, we utilized the acoustic reflection to measure glottic cross-sectional area in 44 non-smoking, non-obese, healthy subjects, 25 men and 19 women. Glottic area was measured during a continuous slow expiration from total lung capacity (TLC) to residual volume (RV). We compared glottic areas in men and women at three lung volumes: TLC, 50% of vital capacity (VC), and RV. We found that in all but 2 subjects, glottic areas at TLC was greater than at 50% VC or RV. At any given lung volume, there was no significant difference in glottic area between men and women. The reduction in glottic area between TLC and RV was also similar between men and women (36 +/- 24% and 33 +/- 21%, respectively). However, this reduction in glottic area occurred mainly at low lung volumes in women, and more uniformly throughout the vital capacity range in men. We conclude that changes in glottic dimensions are dependent on lung volume, that healthy men and women have similar glottic areas, and that the glottic aperture shows similar variation with lung volume among both sexes.

Magnetic resonance imaging of head and neck tumors

Magnetic resonance imaging has revolutionized the imaging of head and neck malignancies and is now rapidly replacing computed tomography as the study of choice in the majority of lesions in the head, neck, larynx, hypopharynx, oropharynx, paranasal sinuses, paranasopharynx, and skull base. CT scanning can be used in the same region; however, inflammation obtained in CT is not as clearly demonstrated and in some situations, such as malignancies of the tongue, the lesions may be missed entirely. There are still occasional difficult clinical problems when the two studies are complementary, but this situation will definitely be rare.

Magnetic resonance imaging of the head and neck

Magnetic resonance imaging (MR) has already gained wide acceptance in the evaluation of intracranial and spinal canal abnormalities. MR also provides excellent resolution of certain tumors of the head and neck and is particularly useful for the evaluation of neoplasms in the vicinity of the skull base. The absence of a bone signal prevents the streaking artifact so troublesome with computerized axial tomography (CT) and allows better definition of tumor. MR does not use ionizing radiation and appears to be an innocuous imaging mode--thus multiple examinations in young patients are not objectionable with MR. The ability to obtain images in multiple planes by control of the magnetic gradients allows for axial, sagittal, and coronal imaging, without changing the supine position of the patient. Multiple projections are helpful in providing better preoperative assessment of the extent and size of certain neoplasms of the neck.

Magnetic resonance imaging of the larynx: a correlation with histologic sections

To date, high-resolution computed tomographic (CT) scanning has proved to be the most valuable preoperative study for the evaluation of the anatomic extent of head and neck cancers. Now, with the development of magnetic resonance (MR) imaging, the prospect of having an equally reliable test without associated radiation exposure has emerged. This study is designed to compare MR images of the larynx with corresponding histologic sections obtained by step-serial sectioning of whole organ specimens. Images were generated by a 0.3 Tesla permanent magnet MR imager. Additional correlation with CT scans was obtained when possible. CT resolution proved to be slightly superior in the axial plane but markedly inferior to MR imaging in the coronal and sagittal planes. Overall, MR imaging appeared to have good resolution of the larynx.

Magnetic resonance imaging of the neoplasms involving the head

Magnetic resonance (MR) imaging is a new method for producing high quality tomographic images with improved soft-tissue definition. MR imaging is conceptually quite different from conventional imaging modalities. A number of variations in MR technique may be chosen to provide better resolution or improved specificity. Some of the current and future roles of MR in the evaluation of both cranial and extracranial neoplasms involving the head are discussed.

Magnetic resonance. Principles and applications

Magnetic resonance is a unique, noninvasive imaging modality which allows direct, multiplanar imaging and the possibility of obtaining biochemical information in vivo. Presently, MR appears most applicable to the evaluation of central nervous system abnormalities. The high sensitivity of MR in the evaluation of intracranial pathology suggests that it may eventually replace CT for many suspected diseases, if future investigations are able to improve its specificity. As previously noted, MR may be more diagnostic than other radiologic studies in the evaluation of suspected Chiari malformation, syringomyelia, congenital abnormalities, tumors of the spinal axis, and disc space infection. In the chest, MR appears to be more accurate than CT in the determination of the extent of mediastinal tumor, but at present cannot replace CT because of the lack of experience in imaging parenchymal nodules and benign diseases. MR of the breast is promising, but the size of the lesion may prove to be a limiting factor with magnetic field strengths commonly being utilized. There are inherent difficulties in the evaluation of cardiac disease with MR, but it offers a noninvasive method of investigating congenital heart disease and may provide valuable information in suspected myocardial ischemia and altered cardiac function. MR provides a new method of evaluating the vascular system, both in terms of providing anatomic information on large and medium-sized vessels and flow analysis. In the abdomen, MR appears to be most sensitive in the evaluation of suspected hepatic masses, but as with the brain, greater specificity will be needed to replace CT. At the present time, MR offers no distinct advantage over conventional imaging modalities in the evaluation of pancreatic disease, it maybe more accurate than CT in the staging of renal cell carcinoma. Larger studies are needed to determine the role of MR in the investigation of retroperitoneal adenopathy and adrenal abnormalities. In the pelvis, MR offers the hope of earlier diagnosis of prostatic carcinoma and may replace CT for staging of prostatic carcinoma and transitional cell carcinoma of the bladder. Limited MR experience with benign disease of the female pelvis suggests that it is currently more accurately evaluated with ultrasound. MR appears to be highly sensitive and specific for the diagnosis of avascular necrosis and may provide an early clue in suspected osteomyelitis. Finally, in vivo MR spectroscopy may provide unique metabolic information that was unobtainable prior to the advent of magnetic resonance, if this proves to be technically feasible.