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Biomedical subjects

C Czerny

Publications and source records attributed to C Czerny.

At least 73 records · Page 4Linked to original sources
PubMed1998

Cochlear implantation as a successful rehabilitation for radiation-induced deafness.

Radiotherapy of the head and neck can be associated with conductive and/or sensori-neural hearing loss. We report the case of a 67-year-old man who developed complete bilateral deafness caused by labyrinthitis and radiation-induced neuritis of the acoustic nerve after postoperative radiotherapy of a nasopharyngeal carcinoma. Two years postoperatively extensive clinical workup including computed tomography and magnetic resonance imaging showed no recurrence or secondary brain tumors. To facilitate sound perception a Combi 40 cochlear implant was implanted. Because of fibrosis the insertion depth of the stimulating electrode into the scala tympani was limited and therefore a "short electrode version" was used. Six months after implantation the patient had achieved an excellent environmental sound recognition and moderate speech intelligibility. Present experiences has shown that although radiotherapy can cause damage to the labyrinth and acoustic nerves and central hearing pathways, there may still be surviving auditory nerve fibers that can be stimulated successfully by a cochlear implant.

Aged↗
PubMed1998

Genotoxicity and mutagenicity of the alpha, beta-unsaturated carbonyl compound crotonaldehyde (butenal) on a plasmid shuttle vector.

Crotonaldehyde is an alpha,beta-unsaturated carbonyl compound and an important environmental and industrial toxic substance. Its mutagenic and carcinogenic properties are related to its reactivity to DNA, where it forms different guanine adducts. In order to study the mutagenic consequences of this agent in intact human cells, we treated the shuttle vector plasmid pZ189 with different doses of crotonaldehyde at 37 degrees C for 2 h and then transfected the such damaged plasmid into the normal human lymphoblast cell line GM0621. Within these host cells the guanine adducts are repaired and the plasmids replicated by cellular enzymes. After 2.5 days replicated plasmids were purified from the cells and plasmid survival was quantitated by transformation ability. With increasing doses of crotonaldehyde, we found a significant decline of plasmid survival, reflecting a pronounced genotoxicity of crotonaldehyde-induced DNA damage in intact human cells. Using the plasmid encoded mutagenesis marker gene supF, we were able to screen for mutants and determine mutation frequency in recovered plasmids. A significant increase in mutation frequency with increasing doses of crotonaldehyde reflects mutagenicity of crotonaldehyde-induced DNA damage. Base sequence analysis of recovered mutants revealed 39% point mutations, 46% deletions, and 15% insertions and inversions. Most of the point mutations (82%) were located at G:C base pairs, which is well explained by the DNA damage profile of crotonaldehyde. Among deletions we found a frequent reoccurrence of two hot spot deletions, representing 62% of all deletions. The sites of breakpoints of these deletions hot spots and of other deletions within the plasmid were also found to be sites of DNA breaks, directly induced by crotonaldehyde, as seen in an endlabeled plasmid fragment, treated with crotonaldehyde. Further analysis of the flanking sequences around the deletion breakpoints revealed a high frequency of four different kinds of short sequence homologies of up to eight base pairs.

Aldehydes↗
PubMed1998

Localization of the mandibular neurovascular bundle using dental magnetic resonance imaging.

OBJECTIVE: To assess the reliability of a commercially available 3D-MPR MRI program for the jaws for imaging the mandibular neurovascular bundle. METHODS: A gradient echo sequence (TR: 49 ms/TE: 6.3 ms/flip angle: 25 degrees/excitations: 3) with a spectral fat suppression pre-impulse and a voxel size of 0.9 x 0.9 x 0.8 mm was designed. Cross-sectional and panoramic reconstruction of the whole mandible were performed from the axial scans using Easy Vision (Philips, Best, The Netherlands) software package. The ability of differentiate the mandibular neurovascular bundle was assessed in 11 patients. RESULTS: The mandibular neurovascular bundle was clearly visualized in all cases. CONCLUSION: Dental MRI is a possible alternative to plain films or CT for patients requiring surgery near the mandibular canal.

Anatomy, Cross-Sectional↗
PubMed1998

MR imaging of the inner ear and cerebellopontine angle: comparison of three-dimensional and two-dimensional sequences.

OBJECTIVE: The aim of the study was to compare the ability of three-dimensional (3D) T2-weighted turbo spin-echo and gadolinium-enhanced 3D T1-weighted gradient-echo sequences with two-dimensional (2D) T2-weighted turbo spin-echo and gadolinium-enhanced T1-weighted spin-echo sequences to reveal anatomic and pathologic structures of the inner ear and cerebellopontine angle. SUBJECTS AND METHODS: Thirty-one patients underwent axial 2D T2-weighted turbo spin-echo and 3D T2-weighted turbo spin-echo MR imaging, axial and coronal 2D T1-weighted spin-echo MR imaging before and after i.v. injection of gadopentetate dimeglumine, and gadolinium-enhanced axial 3D T1-weighted gradient-echo MR imaging. The visualization of anatomic and pathologic structures on the different sequences was evaluated. Statistical analysis was performed from the data obtained from the visual evaluation of the anatomic structures on the different sequences. Signal-to-noise and contrast-to-noise ratios were calculated for the gadolinium-enhanced 3D T1-weighted gradient-echo and 2D T1-weighted spin-echo sequences, and statistical evaluation was performed. RESULTS: The 3D sequences enabled excellent visualization of 94% of all evaluated anatomic structures, and the 2D sequences enabled excellent visualization in only 3% of these structures. Pathologic structures were revealed in all cases by one or both of the 3D sequences. Diagnosis in all patients could be made by using the combination of the 3D T2-weighted turbo spin-echo and the gadolinium-enhanced 3D T1-weighted gradient-echo sequences. However, the 2D sequences failed to show pathologic structures in three patients. We found a significant statistical difference for the visualization of anatomic structures with the 3D and 2D sequences (p < .0001) and no significant statistical difference for the signal-to-noise and contrast-to-noise ratios with the 3D T1-weighted gradient-echo and 2D T1-weighted spin-echo sequences. CONCLUSION: The 3D sequences revealed anatomic structures significantly better than did the 2D sequences and showed pathologic structures considerably more often than did the 2D sequences in all patients. MR imaging of the inner ear and cerebellopontine angle performed with 3D T2-weighted turbo spin-echo and gadolinium-enhanced 3D T1-weighted gradient-echo sequences provided the most accurate imaging leading to diagnosis in cases of abnormality.

Adult↗
PubMed1998

Indium-111-DTPA-D-Phe-1-octreotide and technetium-99m-(V)-dimercaptosuccinic acid scanning in the preoperative staging of medullary thyroid carcinoma.

UNLABELLED: The early detection of all tumor sites in patients with medullary thyroid carcinoma (MTC) before primary surgery is important, because MTC tends to metastasize to regional lymph nodes of the neck and mediastinum early during the course of the disease. METHODS: In an approach to localize the primary tumor sites and to detect additional tumor involvement, we have performed in 22 patients with MTC either 99mTc(V)-dimercaptosuccinic acid (DMSA) and/or 111In-diethylenetriamine pentaacetic acid-D-Phe-1-octreotide scintigraphy. RESULTS: Indium-111-octreotide (150-200 MBq) identified the primary tumor in 10 of 14 patients (71%), whereas the primary tumor was visualized by 99mTc-DMSA (300-370 MBq) in 10 of 17 patients (58%). In 8 of 22 patients (36%), lymph node metastases were present at the time of diagnosis, as confirmed by histopathology and histochemistry after surgery (all <2 mm). Preoperatively, neither scan was able to detect lymph node involvement in these patients (0/8). CONCLUSION: Both 99mTc-DMSA and 111In-octreotide studies have similar sensitivity to localize primary MTC; however, these scans are not able to detect small lymph node involvement (micrometastases) before initial surgery. Unfortunately, both scans have no clinical implication for preoperative staging in patients with MTC.

Carcinoma, Medullary↗
PubMed1998

[The Donauspital-Stolzalpe concept (Danube Hospital, Vienna, Austria). Corrective osteotomy with selective labrum surgery following preoperative MRI arthrography].

Concomitant pathologies (labral lesions, intra-/extra-osseous ganglia and stress bone marrow edema) in adult residual hip dysplasia (RHD) might influence the outcome of conservative hip surgery. The aim of our prospective clinical study was to assess the value of preoperative MR arthrography in diagnosing concomitant lesions and in making surgical decisions in RHD. The first 37 consecutive patients with a minimum follow-up of 18 months have been analysed. All 37 patients presented RHD with the clinical symptomatology of labral lesions and underwent routine preoperative MRA. According to clinical, radiological and MR arthrographical criteria, these 37 patients were subdivided into four therapeutic subgroups: (1) reorientation of the acetabulum using the Tönnis triple pelvic osteotomy (TPO); (2) intertrochanteric varisation osteotomy (IVO); (3) palliative decompression with only symptomatic partial resection of the torn labrum (PALL); (4) primary total hip replacement (TEP). Based on the preliminary clinical and radiological outcomes of these four subgroups, the following conclusions can be drawn: labral lesions are considered to be a sign of chronic joint instability. Therefore, acetabular malorientation should be corrected by redirectional osteotomy of the acetabulum (TPO-subgroup) even in low grades of RHD if labral lesions are present. "Palliative" labral resections without corrective osteotomy (PALL subgroup) in secondary osteoarthritis due to RHD are definitively obsolete, because they rapidly progress to severe osteoarthritis due to surgically accelerated joint instability. In RHD with highly osteoarthritic hip joints and concomitant lesions, one should not hesitate to perform primary THR even in young patients.

Acetabulum↗
PubMed1997

Ophthalmoplegia as an unusual initial symptom of non-Hodgkins' lymphoma in the head and neck.

Non-Hodgkins' lymphomas are relatively common tumors in the head and neck and should always be considered in the differential diagnosis of any mass lesion in this region, especially in cases with single enlarged lymphnodes of unknown origin and symptoms that can only be explained by metastasis. The diagnosis is usually established by multidisciplinary collaboration. We report our experience in managing a 48-year-old man who was found to have a non-Hodgkins' lymphoma in his neck that was complicated by a metastasis to his brain causing incomplete ophthalmoplegia, a rare primary complication. The differential diagnosis and the examinations leading to the diagnosis are discussed.

Brain Neoplasms↗
PubMed1997

[MRI on low-field tomography systems (0.2 Tesla). A quantitative comparison with equipment of medium-field strength (1.0 Tesla)].

AIM OF THE STUDY: Using phantom studies, a dedicated low-field MR system with 0.2 T and a whole-body MR-scanner with 1.0 T were compared. METHODS: A spin-echo sequence was performed on the 0.2-T MR unit using the knee coil and on the 1.0-T MR unit with the head coil. In a water-filled phantom, signal-to-noise ratios (SNR) were calculated and contrast measurements on gels with well-defined relaxation times were obtained and compared to nominal relaxation times. Measurements of T1 and T2 relaxation times on the low-field system were compared to the 1.0-T unit. As a parameter for geometrical image quality, magnetic field distortions were calculated. In theory, influence of field strength and and receiver bandwidth on the minimal echo time and on chemical shift artifacts were calculated. RESULTS: The SNR was 63.2 on the 0.2-T and 179.6 on the 1.0-T MR unit (difference factor 3, against a theoretical difference of 5-16). Relaxation times on the low-field system were significantly (around 40-50%) lower. Measurements of contrast were similar on both systems. On the low-field system geometrical distortions of several pixels were recorded. The minimal echo time on the low-field system was 21.3 ms with the low receiver bandwidth and 4.3 ms on the 1.0-T MR unit. The amount of chemical shift artefacts was the same on both systems. DISCUSSION: On low-field MR systems SNR is markedly improved by small read-out gradients and a low receiver bandwidth (factor 3 vs 5-16 in comparison with the 1.0-T MR unit). However, an optimal homogeneous magnetic field is required, since inhomogeneities may create severe geometrical distortion.

Artifacts↗
PubMed1997

[Imaging of the middle ear. CT and MRI].

High-resolution computed tomography (HRCT) provides excellent contrast between osseous structures, air and soft tissue in conjunction with high spatial resolution. Therefore, thin-section HRCT with bone window setting is the method of choice for the examination of the middle ear structures. The indications are acute and chronic inflammatory changes, cholesteatoma and tumor, the "postoperative middle ear", and malformations. In most cases, HRCT enables differentiation between inflammatory changes, cholesteatoma, and tumor. The excellent depiction of subtle osseous details enables the identification of erosions of the ossicles or of the bony walls of the mastoid cells, of osseous defects of the tegmen, of the bony labyrinth, and of the tympanic course of the facial canal. In addition, HRCT enables excellent depiction of reconstructions of the ossicles or prosthesis of the ossicles. Although HRCT is the first method of choice, magnetic resonance imaging (MRI) may provide additional information and lead to a more accurate diagnosis in some cases. This is explained by the excellent soft tissue contrast provided by MRI. In addition, MRI offers the possibility of using various pulse sequences and the administration of i.v. contrast material. Therefore, MRI may allow the differentiation between inflammatory changes, cholesteatoma, and tumor in those cases in which accurate diagnosis cannot be made by HRCT. The differentiation between a meningocele or meningoencephalocele and other entities such as tumors or cholesteatoma can be established by MRI. Furthermore, MRI can accurately depict cases of labyrinthitis or of neuritis of the facial nerve or of intracranial disease caused by middle ear processes, while this is not always possible by HRCT. In summary, HRCT of the middle ear is the method of choice, but MRI may provide supplementary information in those cases in which accurate diagnosis cannot be established by HRCT.

Ear Diseases↗
PubMed1997

[Temporal bone trauma and imaging].

Fractures of the temporal bone result from direct trauma to the temporal bone or occur as one component of a severe craniocerebral injury. Complications of temporal trauma are hemotympanon, facial nerve paralysis, conductive or sensorineur hearing loss, and leakage of cerebrospinal fluid. Early recognition and an appropriate therapy may improve or prevent permanent deficits related to such complications. Only 20-30% of temporal bone fractures can be visualized by plain films (7). CT has displaced plain radiography in the investigation of the otological trauma because subtle bony details are best evaluated by CT which even can be reformatted in multiple projections, regardless of the original plane of scanning. Associated epidural, subdural, and intracerebral hemorrhagic lesions are better defined by MRI.

Ear↗
PubMed1997

[Rehabilitation of patients with hearing loss by cochlear implants].

In the last decade, the rehabilitation of postlingually deaf adults and prelingually deaf children with cochlear implants has been established as a treatment of deafness. The technological development of the implant devices and improvement of the surgical technique have led to a considerable increase of hearing performance during the last years. The postlingually deaf adults are able to use the telephone and may be integrated in their original job. Prelingually deaf children can even visit normal schools after cochlear implantation and hearing rehabilitation training. In order to preoperatively establish the state of the cochlea, radiological diagnosis of the temporal bone is necessary. High resolution computerized tomography imaging of the temporal bone with coronar and axial 1 mm slices and MRI with thin slice technique (three dimensional, T2 weighted turbo-spinecho sequence with 0.7 mm slices) have proved to be valuable according to our experience. Furthermore a postoperative synoptical X-ray, in a modified Chausse III projection, offers good information about the position of the implant and insertion of the stimulating electrode into the cochlea.

Adult↗
PubMed1997

[MRI of the regions of the inner ear and cerebellopontine angle using a 3D T2-weighted turbo spin-echo sequence. Comparison with conventional 2D T2-weighted turbo spin-echo sequences and T1-weighted spin-echo sequences].

PURPOSE: To assess the value of a three-dimensional (3D) T2-weighted turbo spin-echo sequence (3D T2-TSE) in comparison to conventional two-dimensional (2D) T2-weighted TSE and unenhanced and enhanced T1-weighted spin-echo sequences (SE) in imaging anatomic structures and pathologic changes of the inner ear and cerebellopontine angle. PATIENTS AND METHODS: The inner ear and cerebellopontine angle were investigated by MRI in three healthy volunteers and 18 patients performing a 2D T2-weighted turbo spin-echo sequence and a 3D T2-TSE in the axial plane. In the patient study, 2D T1-weighted SE sequences both before and after the i.v. injection of gadopentetate dimeglumine in both the axial and coronal plane were performed in addition. RESULTS: Only the 3D T2-TSE enabled an accurate imaging of the anatomic structures. In cases of pathology, the 3D T2-TSE provided additional information to the performed 2D sequences. The combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted SE enabled the most accurate diagnosis in cases of pathology. CONCLUSIONS: Accurate depiction of anatomic structures of the inner ear and cerebellopontine angle could be obtained by 3D T2-TSE only. The most accurate diagnosis in cases of pathology was provided by the combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted spin-echo sequences.

Adult↗
PubMed1997

Postoperative radiographic assessment of the Combi 40 cochlear implant.

OBJECTIVE: The aims of this study were to establish a plain radiographic technique for the assessment of the postoperative appearance, position, and insertion depth of the Combi 40 cochlear implant and to correlate the radiologic findings with surgical reports. SUBJECTS AND METHODS: In an experimental study, an electrode of the Combi 40 device was inserted into the cochlea of a cadaveric skull. Digital radiographs were obtained in a modified Chausse III projection, in which the skull was placed supine on the radiography table with the infraorbitomeatal line strictly perpendicular to the film cassette. The skull was then rotated 30 degrees away from the side to be examined, and the central X-ray beam was angled 15 degrees cephalad to the infraorbitomeatal line. On these radiographs, the point of cochleostomy was marked by a needle tip and was projected inferior to the vestibule and on a line drawn through the superior semicircular canal and the vestibule. The appearance and position of the electrode was evaluated. An electrode was defined as completely inserted if all electrode contacts projected medial to the line drawn through the superior semicircular canal and the vestibule. We also studied cochlear implant insertion of the Combi 40 device in 37 patients. Postoperative digital radiographs of these patients were obtained and analyzed for the criteria as defined in the cadaveric study. In addition, the insertion depth of the electrode and the angle of insertion were measured on the radiographs. This depth was correlated with depth of insertion as estimated at surgery. RESULTS: The cadaveric study showed that the completely inserted electrode was seen on radiographs as a nonoverlapping spiral within the cochlea. All electrode contacts projected medial to the line drawn through the superior semicircular canal and the vestibule. In all 37 patients, the electrode could be seen without overlapping. According to our criteria, a completely inserted electrode was seen in 32 patients. In these patients, the insertion depth ranged from 21 to 34 mm and the angle of insertion ranged from 350 degrees to 810 degrees. In two patients, we saw a completely inserted electrode with a bend. In three patients, an incompletely inserted electrode was seen. Excellent correlation existed between the radiologic and surgical results with regard to insertion depth (r = .92). CONCLUSION: Digital radiographs obtained in the modified Chausse III projection allow clear depiction of the electrode and avoid overlapping. Such radiographs enable a reliable and accurate assessment of the position and insertion depth of the electrode of this new cochlear implant. Such images can serve as a baseline for further radiographic examinations when extrusion or slippage of the electrode is clinically suspected.

Adult↗
PubMed1997

Cochlear implant deep electrode insertion: extent of insertional trauma.

We have recently undertaken deep insertions of the Combi-40 cochlear implant electrode (Med-E1 Corp., Innsbruck, Austria) into apical regions of the scala tympani using a cochleostomy approach. In order to examine the extent of the insertional trauma, 12 fresh human temporal bones were implanted with original Combi-40 electrodes. The specimens were histologically processed with the implants in place by employing a sawing and grinding technique. In most cases, only very discrete distortions of the epithelium of the spiral ligament occurred within the middle cochlear turns. Furthermore, a slight displacement of the basilar membrane caused by the electrode was occasionally seen. However, in 2 cases more severe damage such as basilar membrane rupture and electrode displacement was found. Attempts to insert the electrode beyond the point of first resistance resulted in electrode kinking within the basal cochlear turn with subsequent fracture of the osseous spiral lamina. According to our results, deep electrode insertions do not aggravate the insertional trauma provided no force is applied when resistance is felt.

Cochlea↗
PubMed1996

[Differential diagnosis of diseases of the Achilles tendon. A clinico-sonographic concept].

Ultrasound of the Achilles tendon is a suitable means of differentiating various diseases of the tendon and the surrounding tissue. Different forms of degenerative disease (tendinitis, peritendinitis or bursitis, fibroosteitis, and Haglund's disease) can be discriminated from rheumatic and metabolic diseases. Congenital and developmental abnormalities can also be detected. Tendon degeneration mainly occurs in the ventral part of the medial third of the tendon ("critical zone"). Immature tissue in this area leads to temporary [correction of temorary] instability of the tendon with a high risk of rupture ("vulnerable phase"). With sonography, lesions of the Achilles tendon are visible early in the course of the disease.

Achilles Tendon↗
PubMed1996

[MRI and ultrasound in rheumatology].

Technical innovations and software improvements in magnetic resonance imaging (MRI) and high-resolution sonography (US) have definitely influenced the diagnostic imaging of rheumatic diseases. For MRI, improvements in surface coils, dedicated low-field systems (0.2 T), and software improvements (shorter acquisition times and refinements of fat suppressing techniques) must be mentioned. For sonography, the main innovations concern the development of higher transducer frequencies (7-15 Mhz) and power Doppler imaging. Clinical evaluations have shown that MRI and US are most useful in cases of suspected rheumatic disease with negative plain film radiographs and for documenting the course of the disease, diagnosing of early rheumatoid arthritis, making a differential diagnosis in clinically unclear rheumatic diseases, investigating vascularization, and quantifying pannus formation. In order to improve diagnostic efficacy the role of MRI and US in the management of patients with rheumatic disease should be reconsidered.

Arthritis, Rheumatoid↗
PubMed1996

MRI in assessment of the systemic manifestations of rheumatological disease.

Magnetic resonance imaging (MRI) has emerged as complementary imaging modality to conventional radiography. The same diagnostic rules that are used in the interpretation of the routine radiographs should be applied to the analysis of MR images with the macroscopic spread of the disease as a main diagnostic clue. MRI has been shown to be a sensitive tool in detecting early arthritic changes and erosions, inflammation in periarticular tendons and tendon sheaths, and in juxtaarticular bursae. MRI plays a pivotal role in diagnosis of arthritis of the craniocervical junction and its complications. It also has been used effectively to detect insufficiency fractures and osteonecrosis. MRI may be important in diagnosing early arthritis, in specifying the differential diagnosis of rheumatic disease, and in selecting subgroups of patients to provide tailored therapeutic regimens.

Arthritis, Rheumatoid↗