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Biomedical subjects

G Grevers

Publications and source records attributed to G Grevers.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Extracranial schwannoma of the ENT region. Review of the literature with a case report of benign schwannoma of the base of the tongue].

BACKGROUND: Schwannomas are benign, usually solitary, encapsulated neoplasms which arise from the Schwann cells of the nerve sheath. They often originate from the VIIIth cranial nerve. Extracranially, about 25% of all Schwannomas are located in the head and neck. The lateral cervical region and the mouth are the most common sites. Schwannomas arising from the base of the tongue are very rare, and only a few cases have been reported so far. CASE REPORT: We add the case of a 31-year-old woman who had been suffering from slowly increasing dysphagia for about 4 years. Examination revealed a firm, smooth-shaped, nodular swelling about 3.0 cm in diameter arising from the base of the tongue. SYMPTOMS AND DIAGNOSIS: The symptoms of Schwannomas are nonspecific, and depend on size and location. Sonography, CT or MRI may be helpful for estimation of the tumor margins and infiltration of surrounding structures. To confirm the diagnosis, however, microscopic examination is necessary. Characteristic histological signs are the palisading of the spindle-shaped Schwann cells around the central acellular area (so-called Verocay bodies). THERAPY AND PROGNOSIS: The therapy of choice consists of surgical removal of the tumor; Schwannomas do not recur if they are completely removed. In contrast to multiple neurofibromas (von Recklingshausen's disease) Schwannomas almost never undergo malignant transformation.

Adult↗
PubMed1996

Morphological variability of smooth muscle cells in human nasal swell bodies.

The complex functional behavior of nasal swell bodies is still not completely understood. In the present study the histology of the vessels involved in the swelling mechanism is examined and the ultrastructural appearances described of the different types of smooth muscle cells located in the vascular wall of swell bodies in the human inferior turbinate. Even though the majority of smooth muscle cells of the nasal swell bodies showed a normal, elongated appearance comparable to other smooth muscle cells elsewhere in the body, a variety of cells with atypical shapes could be detected that have not been described previously in vessels of the nasal mucosa. The diameters of the smooth muscle cells in general were strikingly variable. The individual smooth muscle cells were surrounded by a basal lamina that was occasionally disrupted or doubled. Myoblasts were separated by a connective tissue space containing collagen fibrils, mature elastin fibers and bundles of microfibrils. The latter two types of fibers and fibrils occurred mainly in the outer parts of the muscular coat. The endowment of cytoplasmic components was similar in all smooth muscle cells of the vascular wall in the swell bodies. These findings indicate that the specific feature of smooth musculature presumably resides in the unusual morphological variability of the single cells present, as well as in the striking heterogeneity of the arrangement of bundles of these cells in the vascular wall.

Connective Tissue↗
PubMed1996

Sjoegren's syndrome: MR imaging of the parotid gland.

To date, myoepithelial sialoadenitis (Sjoegren's syndrome) has been diagnosed with sialography and other techniques. First results of MR imaging offer new possibilities in the diagnostic imaging of this disease. Thirty-six patients with immunohistologically and serologically confirmed Sjoegren's syndrome and 25 patients suffering from other diseases, included as a control group, were examined by MR in transverse and coronal orientation. T-2-weighted sequences (TR/TE 1600/25/90) and T1-weighted sequences (TR/TE 500/25 ms) plain and after Gd-DTPA administration were obtained. In all patients the parotid gland showed characteristic internal patterns and abnormalities in gland size. There was a nonhomogeneous internal pattern with a characteristic speckled, honeycomb-like appearance visible especially on T2-weighted sequences. Enhancement with Gd-DTPA yielded no additional information. A staging system with four stages of Sjoegren's syndrome (no characteristic changes to a nodular and swollen gland) was developed. Magnetic resonance has become an important new tool in assessing parotid gland changes in patients suffering from Sjoegren's syndrome, and could well replace the more invasive and unpleasant diagnostic methods in the near future.

Acute Disease↗
PubMed1996

[Clinical differential diagnosis of the mouth and oropharynx].

In the present paper, common disorders of the oral cavity and oropharynx are described with special emphasis on differential diagnostic aspects. The first part of this presentation covers different inflammatory diseases, mainly focusing on complications like peritonsillar, para- and retropharyngeal abscesses, and Ludwig's angina. These clinical entities can lead to further life-threatening complications, including deep neck infections and mediastinitis. The diagnostic value and necessity of modern imaging in these cases are emphasized. In the second part, the author reports on the incidence, etiology and clinical course of tumors of the oral cavity and oropharynx with special regard to malignancies. Tumors in these areas have been increasing in number over the past decades mainly due to changes in alcohol and nicotine consumption in the developed countries. Diagnostic management includes a thorough clinical evaluation as well as modern imaging for tumor delineation and possible bone infiltration, depending on the site of the original tumor. In addition, therapeutic considerations are discussed, focusing on surgical tumor removal and soft tissue replacement using different pedicled flaps and free flaps. It is also emphasized that postoperative radiotherapy is mandatory in most malignant tumors in this area.

Diagnosis, Differential↗
PubMed1996

[Computerized tomography of malignancies of the oral cavity, the oropharynx and hypopharynx and invasiveness].

Carcinomas of the oral cavity, oropharynx and hypopharynx represents 5% of all malignant neoplasms. The vast majority, over 90%, are squamous cell carcinomas; less common are lymphomas and tumors of the minor salivary glands. In general, the clinical findings already suggest the presence of a tumor. Therefore, the role of imaging is precise tumor localisation and staging of the malignancy. CT is still the gold standard, although MRI is gaining more importance. We present the CT appearance of most frequent malignancies of the oral cavity, oro- and hypopharynx, discussing briefly the pertinent anatomy.

Carcinoma, Squamous Cell↗
PubMed1996

[Value of fat signal suppression MRI pulse sequences for diagnosis of malignant tumors in the area of the head-neck].

PURPOSE: Evaluation of frequency-selective fat saturation (FS) and short-tau inversion recovery (STIR) fat suppression (FU) in MRI of patients with malignant head and neck tumors. METHODS: Forty-five patients with biopsy-proven carcinomas of the extracranial head and neck were examined with MRI at 1.0 T. A T2-weighted TSE sequence with and without STIR-FU and a T1-weighted SE sequence with and without FS were compared in axial slices. RESULTS: STIR-FU was successful in all and FS in 85-88% of the head examinations (nasopharynx, sinuses, oropharynx, and oral cavity) and 33-46% of the neck examinations (hypopharynx and larynx). When visualization and delineation of tumors were ranked on a four-point scale (0-3), respective mean values for images with/without FU or FS were 2.6/1.9 for T2-TSE in all examinations, 2.2/1.7 (nasopharynx and sinuses) and 1.3/1.4-1.6 (oropharynx, oral cavity, hypopharynx, and larynx) for T1-SE without contrast media administration (CM) and 2.3/2.1 (nasopharynx and sinuses) and 2.4-2.5/1.9-2.0 (oropharynx, oral cavity, hypopharynx, and larynx) with CM. CONCLUSIONS: STIR-T2-TSE was a technically reliable pathfinder for localization and extension of both tumors and lymph nodes. FS-T1-SE was technically unreliable in examinations of the hypopharynx and larynx. With CM, FS-T1-SE was most useful for MRI of carcinomas of the oral cavity and oropharynx. In the nasopharynx and sinuses, T1-SE with CM and FS-T1-SE with or without CM were equal for tumor visualization and delineation.

Adipose Tissue↗
PubMed1996

[Short tau inversion recovery fat suppression in T2-weighted turbo spin echo-MRI of malignancies of the mouth and oropharynx].

BACKGROUND: T1-weighted sequences before and after the application of contrast medium and T2-weighted sequences are used for magnetic resonance imaging of malignomas of the oral cavity and the oropharynx. The authors studied the utility of short tau inversion recovery fat suppression (STIR) in T2-weighted turbo spin echo sequences (TSE). METHODS: Twenty patients with malignomas of the oral cavity and oropharynx were examined on a 1.0 Tesla magnetom using T2-weighted TSE-sequences with and without STIR as well as T1-weighted spin echo sequences before and after the application of contrast medium. RESULTS: STIR was successfull in all patients. STIR worsened the signal-noise-ratio significantly, but improved tumor delineation compared to T2-TSE without fat suppression in 75% according to three different investigators. CONCLUSION: The STIR technique is beneficial for the progress in diagnostic imaging of cancer of the oral cavity and oropharynx.

Adipose Tissue↗
PubMed1996

[Cat scratch disease. An overview for the ENT physician].

BACKGROUND: Cat scratch disease (CSD) is a relatively common cause of chronic lymphadenopathy in the USA. In the present paper the authors describe recent advances in the understanding of this disorder focusing on etiology, clinical aspects, diagnostic management, and therapy. ETIOLOGY: Rochalimaea henselae and Afipia felis, two gram-negative bacteria, have recently been isolated from lymph node tissue of patients suffering from CSD. The current literature reveals that Rochalimaea henselae seems to be the most probable agent responsible for CSD. Serum samples from CSD patients' cats have shown titers of 1:64 or higher for antibodies to Rochallmaea henselae. EPIDEMIOLOGY: The incidence of CSD in the USA is between 0.77 and 9.3 per 100,000 per year. The incidence of CSD in Europe is unknown, but the prevalence of antibodies to Rochalimaea henselae among cats is comparable. CLINICAL MANIFESTATIONS: Most common symptoms of CSD are regional lymphadenopathy, fever, and malaise. Other manifestations occur in about 5% of patients and include encephalitis, granulomatous hepatitis, and Parinaud's oculoglandular syndrome. Fatal complications and irreversible sequelae have not been reported. DIAGNOSIS: To establish the diagnosis of CSD, the presence of regional lymphadenopathy, cat contact, and papula are required. Additional procedures include indirect fluorescent antibody assays and PCR. THERAPY: Up to now there is no standard therapy for CSD. Antibiotic treatment, however, might be considered for CSD patients with severe symptoms. Rifampicin, ciprofloxacin, trimethoprim sulfamethoxazole, and gentamicin are known to be effective antibiotic agents.

Adolescent↗
PubMed1996

[Local anesthesia in operations of the head-neck area].

BACKGROUND: Many operations in the head and neck area can be performed under local anesthesia. However, the use of local anesthesia does not automatically reduce the risk for the patient undergoing surgery. RESULTS: In the present paper, the authors discuss local anesthetics used in surgical procedures in the head and neck region. Aminoesters are currently the most commonly used local anesthetics. Local anesthetics vary with respect to the onset and duration of the local anesthetic effect. The choice of local anesthetic depends on the estimated duration of the surgical procedure. Possible side effects of these substances may affect the central nervous as well as the cardiovascular system. Certain changes in serum electrolytes (i.e., hyperkalemia) as well as hypoxia and hypercapnia significantly increase the cardiotoxic potential of local anesthetics. Different vasoconstrictor agents are used in addition to local anesthetics to prolong the duration of the local anesthetic effect and to provide the surgeon with a nearly bloodless field. The two groups of vasoconstrictors used in these days are catecholamines (epinephrine) and vasopressin analogs. Systemic side effects of catecholamines include cardiovascular reaction, mainly in patients with typical risk factors (i.e., coronary heart disease, high blood pressure, or chronic heart failure). Vasopressin analogs produce fewer side effects than epinephrine. Even so, an overdose of these vasoconstrictors might still result in severe cardiac complications. The recommended maximum doses of these drugs should be strictly observed. CONCLUSIONS: For several reasons, local anesthesia has become popular for a variety of surgical procedures in the head and neck in recent years. Even though the use of local anesthetics and vasoconstrictors in head and neck procedures has its advantages for both the patient and the surgeon, the limitations for the use of these drugs must always be taken into consideration.

Anesthesia, Local↗
PubMed1996

[Nasal cerebral heterotopic tissue (nasal glioma) in the adult: a rare cause of primary cerebrospinal fluid rhinorrhea].

BACKGROUND: Nasal cerebral heterotopia is a congenital lesion that is mainly detected in early childhood. The rare cases of this disorder found in adult patients are located intranasally. A common symptom is compromised nasal air passage. Clinical findings include polypoid masses in either the nasal cavity or the paranasal sinuses. To our knowledge, primary cerebrospinal fluid (CSF) rhinorrhea has been reported only twice in these patients. PATIENT: A 64-year-old female patient presented with CSF rhinorrhea proven by beta 2-transferrin testing. Previous head injury or intranasal manipulation were excluded. Anterior rhinoscopy revealed a watery drainage from the right middle meatus. CT scan showed a defect in the lateral roof of the right ethmoid sinus, approximately 5 mm in diameter; MRI revealed a mass in the right ethmoid and frontal sinuses, penetrating the anterior skull base. The lesion was resected by an extranasal approach. It showed a fibrous connection to the frontal lobe. Histologically, the lesion consisted of neural tissue composed of gray and white matter, both with a normal structuring. Dura and skull base were reconstructed. There were no signs of a CSF leak postoperatively. RESULTS AND CONCLUSIONS: The differential diagnosis of CSF rhinorrhea includes traumatic events and neoplasms, elevated intracranial pressure, and connate lesions as encephaloceles and, in rare cases, nasal cerebral heterotopia.

Adult↗
PubMed1996

[Central (reparative) giant cell granuloma of the paranasal sinus].

BACKGROUND: The central giant-cell (reprative) granuloma is an uncommon bone lesion usually located in the mandible and maxilla. In contrast to giant cell tumors of the extra-craniofacial skeleton, the origin of this lesion is considered to be non-neoplastic, reactive, and triggered by trauma or inflammation. The tumor occurs mainly in young people; they complain of regional indolent swelling of the jaw eventually leading to loosening of the teeth. CASE REPORT: In the paper, the authors describe the unusual case of a central giant-cell granuloma in a young male. Diagnostic procedures, adequate therapeutic approach, and an overview of differential diagnostic considerations are provided. RESULTS: The pedunculate tumor was removed surgically. In endoscopic controls no recurrent growth has been seen up to one year after removal. CONCLUSIONS: Even though the giant-cell reparative granuloma is rare, it may also occur in the nasal cavity. Diagnosis is established by histologic findings and the typical clinical appearance. Surgical removal is the treatment of choice.

Biopsy↗
PubMed1996

Functional morphology of nasal blood vessels in humans.

"Secretion" and "obstruction" as predominant clinical symptoms in rhinology affect a great number of patients with disorders of the nose. According to clinical experience as well as morphological investigations, the endonasal vascular system is most likely to be involved in these functional mechanisms. In the present study, we report morphological findings on the angioarchitecture of human nasal mucosa. Meticulous investigation of the structure and ultrastructure of nasal mucosal capillaries revealed differences in the appearance of the endothelial lining. Especially the morphological feature of attenuated fenestrated endothelia in these vessels might be correlated with the functional behaviour under various physiological and pathological conditions. Inspection of the vascular wall of nasal swell bodies revealed differences in the orientation as well as the shape of muscle cells in different parts of this vascular system. The functional role of special morphological features known as muscular bolsters and intervascular muscle fibres for the swelling mechanism of the nasal mucosa is emphasized. Our results enabled us to define the muscular structures that are most probably responsible for constriction and dilatation of nasal swell bodies.

Blood Vessels↗
PubMed1996

Visualization of inner ear structures by three-dimensional high-resolution magnetic resonance imaging.

High-resolution computed tomography (CT) has long been the method of choice in the visualization of the petrous bone, the internal auditory canal, and the cerebellopontine angle. The introduction of magnetic resonance imaging (MRI), especially of the three-dimensional Fourier transformation constructive interference in steady state (3DFT-CISS), has proved to be superior in the detection of soft-tissue lesions in the inner ear. The aim of this study was to visualize small anatomic structures of the inner ear and cerebellopontine angle. The examinations were performed with a standard head coil on a 1.5-T Magnetom ("Vision"; Siemens, Erlangen, Germany). The three-dimensional reconstruction of the cochlea, semicircular canals, and vestibulum allowed detailed visualization, as well as the imaging of cranial nerves VII and VIII. Our results indicate that 3DFT-CISS MRI is a valuable diagnostic tool in the evaluation of inner ear anatomy and pathology; in most cases, however, it must be supplemented by HR-CT.

Aged↗
PubMed1996

MR characteristics of primary extramedullary plasmacytoma in the head and neck.

PURPOSE: To define MR characteristics of primary extramedullary plasmacytoma in the head and neck using a variety of plain and contrast-enhanced MR protocols. METHODS: Six patients with primary extramedullary plasmacytoma in the head and neck were examined clinically and with MR imaging at 1.5 T. The morphologic appearance and signal intensities of the lesions were analyzed and the results of the imaging findings were compared with histopathologic findings. RESULTS: Qualitative analysis showed that five lesions were oval and sharply demarcated without signs of infiltration; the other lesion filled the parapharyngeal space bilaterally. On t2-weighted sequences, the lesions had moderate signal intensity. On plain T1-weighted sequences, the tumors were isointense or slightly hyperintense with respect to surrounding muscles; after administration of contrast medium, four lesions notable enhancement, with distinct central inhomogeneity. CONCLUSION: Although morphologic features or evidence of contrast enhancement do not assure certain diagnosis of extramedullary plasmacytoma, these MR imaging characteristics should prompt the radiologist to include this rare lesion in the differential diagnosis.

Adolescent↗
PubMed1995

[Epistaxis--a stepwise plan for diagnosis and therapy].

Although nosebleed is usually an uncomplicated condition, in extreme cases it can certainly cause complications and even lead to exsanguination. In principle, local causes of bleeding, for example due to changes within the nose itself, need to be differentiated from symptomatic causes (e.g. infectious diseases, hypertension, coagulation disorders, malignant systemic diseases). The present article deals not so much with the details of nosebleed, but rather with the suitable therapeutic measures required. The author has developed a stepped approach which is intended to provide orientational aid in the treatment of this condition.

Catheterization↗
PubMed1995

[The facial nerve in the petrous bone in thin-layer paratransverse and sagittal magnetic-resonance-tomographic T1-spin-echo and FLASH images].

PURPOSE: It is difficult to effect visualization and delineation of the facial nerve and its neighbouring structures in the temporal bone with conventional MRI examination protocols. We tested temporal bone MRI with 2 mm slices and compared T1-weighted FLASH (TR = 400 ms, TE = 10 ms, 90 degrees flip angle) and spin-echo (TR = 540 ms, TE = 15 ms) sequences. PATIENT AND METHODS: 5 volunteers and 14 patients were examined with the head coil of a 1.0T whole body MRI scanner (Impact, Siemens, Erlangen) with para-transversal images orientated parallel to the inferior outline of the clivus and sagittal images orientated along the brainstem. RESULTS: The facial nerve and its neighbouring structures could be reliably visualized and differentiated along its entire course. The FLASH sequence was superior to the spin-echo sequence. 8 of 11 patients with peripheral facial nerve palsy showed contrast enhancement. In two patients, local swelling of the affected facial nerve was evident. CONCLUSION: The MRI technique tested here seems promising for temporal bone examinations.

Adult↗
PubMed1995

[The MRT of malignant tumors of the oral cavity and oropharynx with frequency-selective and inversion-recovery fat-signal suppression].

PURPOSE: Evaluation of frequency-selective fat saturation (FS) and Short-Tau-Inversion-Recovery (STIR) fat suppression (FU) in MRI of patients with malignant tumours of the oral cavity or oropharynx. METHODS: Twenty patients with biopsy-proven squamous cell carcinoma of the oral cavity or oropharynx were examined by MRI at 1.0 T. A T2-weighted TSE-sequence with and without STIR-FU and a T1-weighted SE-sequence with and without FS were compared in axial slices. RESULTS: STIR-FU was successful in all and FS in 29/33 (87.9%) of the examinations. When visualisation and delineation of tumours were ranked on a four-point scale (0-3), respective mean values for images without/with FU or FS of 1.9 and 2.6 for T2-TSE, 1.4 and 1.3 for T1-SE without contrast media administration (CM) and 2.0 and 2.5 with CM were found. Signal/noise-ratios were inferior with FU and FS, but the tumour/muscle intensity ratio in CM-T1-SE improved with FS. CONCLUSIONS: STIR-T2-TSE and FS-T1-SE with CM were most useful for MRI of carcinomas of the oral cavity and oropharynx.

Adipose Tissue↗