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M Lenz

Publications and source records attributed to M Lenz.

At least 91 records · Page 5Linked to original sources
PubMed1991

[Computed tomography of the soft tissue of the neck. Lymph node metastases and their differential diagnosis].

Computed tomography is considered as the method of choice concerning N-staging in patients with known malignant tumours of the head and neck region. The application of an intravenous contrast medium (50 ml as a bolus, 100 ml as a fast infusion) is obligatory. In lesions of the neck with unknown histology the plain CT scan is important followed by the application of contrast medium, optional in form of a dynamic sequential CT. Calcifications, the densities pre and post contrast medium application, the curve of enhancement and the structure of the lesion are the important criteria of differential diagnosis.

Diagnosis, Differential↗
PubMed1991

Imaging of the oropharynx and oral cavity.

Imaging methods play a significant role in the diagnosis of oropharynx and oral cavity lesions. Contrast-enhanced CT has been established as the baseline technique for T- and N-staging of malignomas. CT yields significant additional information to clinical methods, especially in examining large tumors. With an examination time of only 10 minutes, it is the method of choice. MR imaging requires more time (40 minutes or more) but the superior tissue contrast allows the depiction of smaller lesions. The use of fast gradient-echo sequences in combination with the application of gadolinium diethylenetriamine penta-acetic acid offers new perspectives. High-resolution real-time ultrasound in the hands of an experienced examiner may be helpful because it is easily available; however, it does not allow a complete tumor staging.

Diagnostic Imaging↗
PubMed1990

[The clinical value of contrast CT in lymph node staging in the neck region].

Pre-treatment CT examinations of 333 patients with squamous carcinomas in the head and neck region have been analysed. Two hundred and six patients had lymph-node metastases and lymph-node staging was ascertained. The criteria for metastatic involvement were lymph node size greater than 15 mm. and changes in structure (inhomogeneity, central hypodensity and ring enhancement). CT had a sensitivity of 93% and accuracy of 89%. This was better than palpation (sensitivity 64%, accuracy 72%). CT can be regarded as a reliable basis for treatment planning.

Adolescent↗
PubMed1990

[T-staging of tongue and mouth floor tumors: comparison of ultrasonography and computerized tomography].

A comparison was made between the pretherapeutic CT and ultrasound findings of 43 patients with tumors of the oral tongue and the floor of the mouth. Two tumors of the edge of the tongue (T1) each were not diagnosed by computed tomography and by sonography. In three cases a more precise determination of the tumor size was achieved by sonography. In 25 out of 38 cases the contrast between tumor and sound tissue was better in the sonographic image. The reduction and regressive modification of the tumor following to radiotherapy could be observed in eleven cases. Despite the benefits of sonographic investigation in this area due to the excellent contrast without any need of contrast media, the good availability and the absence of metal and movement artefacts, this method is not able to replace computed tomography. The most important disadvantages of sonography were found to be the incapability to show osseous erosions and the restricted or lacking possibility to assess the parapharyngeal and the retropharyngeal area.

Adult↗
PubMed1990

[Computed tomography of the soft tissues of the neck. Lymph node metastases and their differential diagnosis. I. Methods and the principal CT criteria for lymph node metastases].

Standardisation of the examination method is imperative to guarantee reproducible and valid assessability of the cervical lymph node status. To this end, update high-resolution CT equipment of the third generation will be suitable, provided it meets certain minimum requirements, such as: 120 kV, 280 mAs, 480 projections over 360 degrees, 4-5 mm slice thickness, continuous tomography. If a primary tumour is known to exist, no plain examination is needed. The decisive examination is effected after intravenous administration of contrast medium in a dosage of 2.0-2.5 ml contrast medium/kg body weight (assuming a body weight of 70 kg, this would amount to 150 ml = 45 g iodine), one-third of the total dosage to be given as bolus and two-thirds as a rapid infusion. This procedure ensures sharp definition of lymph nodes against vessels and musculature over the entire period of examination. If tumour anamnesis has been established the size of the lymph node is significant for assessing the lymph node status. Even lymph node metastases less than 15 mm can be properly identified if the structure of the lymph nodes is known and employed as a criterion (central hypodensity with rim enhancement, inhomogeneity).

Carcinoma, Squamous Cell↗
PubMed1990

[Computerized tomography imaging of laryngocele. Its importance in the differential diagnosis of tumors of the larynx and pharynx].

The laryngocele is a dilatation of the laryngeal ventricle and represents a rare condition. In most cases there is a typical history. Patients with an internal laryngocele usually complain of hoarseness, dyspnea and cough. Laryngoscopy shows a swelling of the false cord on one side. The external laryngocele presents as a swelling in the neck. In some cases the clinical presentation is not that typical, so that computed tomography (CT) can be a helpful, additional investigation. CT scans show either an air- or mucus-containing tumor at the level of the false cord. This internal laryngocele may proceed into an external one, which presents as a swelling at the level of the hyoid bone. We now present 13 cases of laryngoceles with special regard to the CT and intraoperative findings. In the differential diagnosis other tumors of the larynx are considered, since the mucus-filled laryngocele is difficult to distinguish.

Adult↗
PubMed1990

[Computerized tomography of the soft tissue of the neck. Lymph nodes and their differential diagnosis. II: Clinical value of CT in lymph node staging].

Basing on an analyses of pretherapeutic CT examinations of 333 patients suffering from squamous cell carcinomas of the head and neck region (206 of these had lymph node metastases), the clinical diagnostic value of CT for lymph node staging was determined. CT criteria for metastatic infestation of the lymph nodes were the lymph node size (greater than 15 mm) and structural characteristics (inhomogenity, central hypdensity with rim enhancement), and it became evident that CT with its 93% sensitivity and 89% accuracy was superior to clinical palpation, where the sensitivity was only 64% and the accuracy 72%. It can be concluded from these results that CT provides a reliable basis for a therapeutic approach.

Adolescent↗
PubMed1989

[Comparison of the results of preoperative studies with imaging procedures with the surgical status of ovarian cancer].

Optimal cytoreductive surgery of ovarian cancer is based on the preoperative diagnosis and assessment of tumour spread. Of 147 patients who underwent staging laparotomy at the Department of Gynaecology of the University of Tübingen, intraoperative staging was compared retrospectively with the results of sonography, computed tomography, double-contrast enema and urography. Ultrasound and computed tomography were comparable concerning accuracy of the diagnosis in 86 and 79% of the cases, respectively. Combined application of both methods resulted in an accuracy of 90%. Involvement of colon was diagnosed by double-contrast enema in only 41% of the cases in which enterotomy had to be performed. Involvement of bladder and ureter was observed in 80% of the cases by intravenous urography. According to our results abdominal ultrasound and urography should be performed in patients with palpable pelvic masses. The application of computed tomography as an additional method is indicated in patients with tumour classified as benign by sonographic examination. Double-contrast enema is of limited value in the diagnosis of colon involvement.

Adolescent↗
PubMed1989

[Magnetic resonance tomography of the oral cavity, the oropharynx and the mouth floor: comparison with computed tomography].

42 CT and MR examinations of orofacial tumours have been analysed and their value has been compared. In 78% of cases MR was superior to CT in delineating the tumour borders. T1-weighted and gradient echo sequences after intravenous gadolinium injection were particularly useful. Nevertheless, T-staging based on clinical and CT findings was altered in only two cases (5%) by MR. MR should, at present, be used in those cases where small tumours can not be demonstrated by CT, or where metal artifacts obscure the region of interest.

Adult↗
PubMed1989

[CT functional images of the larynx and hypopharynx].

Ten healthy volunteers and sixty-four patients with various abnormalities of the hypopharynx and larynx were examined by CT in different functional stages in order to study the normal anatomy and the diagnostic value of CT. CT images during quiet respiration are best for showing small glottic carcinomas. To demonstrate, or exclude, fixation of the vocal cords, it is important to obtain images during "E" phonation. Images during "E" phonation, or during Valsalva's manoeuvre, are essential for demonstrating small carcinomas of the hypopharynx and should be obtained in these cases. These images are also helpful in studying functional abnormalities from paralyses of the recurrent laryngeal nerve, trauma of the larynx and laryngoceles. Images during "E" phonation should therefore be obtained in addition to those during quiet respiration as part of the standard examination of the hypopharynx and larynx.

Cranial Nerve Diseases↗
PubMed1989

[Angiodynography of idiopathic varicocele compared to conventional methods].

21 patients with left-sided idiopathic varicoceles were examined by angiodynography, Doppler sonography and phlebography. Patients treated by sclerosis therapy were re-examined by angiodynography and Doppler sonography after six weeks. Both methods permitted classification into a "stop & shunt type". Angiodynography, particularly for small varicoceles, was quicker and more pleasant for the patient. Real time imaging by angiodynography makes it possible to evaluate pre- and posttherapeutic changes in the pampiniform plexus and in the scrotum.

Adolescent↗
PubMed1989

[The clinical value of computed tomography in the pretherapeutic T-staging of orofacial tumors].

The clinical role of contrast-enhanced CT for pre-operative T-staging of oro-facial tumours was evaluated in 174 patients. During stages T1 and T2, clinical examination is 90% accurate and has a significantly higher sensitivity than CT, with an accuracy of only 53%. The clinical diagnosis of T1 and T2 is, however, made with undue frequency; CT makes it possible to obtain correct staging. Combination of CT and clinical examination can improve correct staging from 46% to 81%. During stages T3 and T4. CT has sensitivity of 91% and is markedly superior to clinical examination, with a sensitivity of 34%. Combined clinical and CT examination improves the predictive value from 52% to 92%. Combination of clinical and CT staging, when the higher stage is accepted as being correct, has a sensitivity and reliability of over 90%. It can be used as a firm basis for treatment planning, judging the prognosis and the effects of treatment.

Adolescent↗
PubMed1987

Idiopathic varicoceles: feasibility of percutaneous sclerotherapy.

Percutaneous retrograde venography was performed in 717 patients with a left-sided idiopathic varicocele. In 674 (94.0%), testicular (internal spermatic) vein insufficiency was proved by contrast medium reflux from the left renal vein into the testicular vein, down to the pampiniform plexus. The different venographic patterns of the testicular veins were classified into seven basic types. Five of these, comprising 624 patients, had incompetent or missing valves all along the trunk of the testicular vein. In 554 of the 624 (88.8%), sclerotherapy was performed, but such treatment was possible in only three of 50 patients with a competent orifice valve bypassed by an insufficient collateral (type IVb). In 43 of the 717 patients (6.0%), no insufficient vein could be found at all (type 0). The mean fluoroscopy time was 4.4 minutes. There were no serious complications associated with venography or sclerotherapy, and the initial recurrence rate was 9.8%. Percutaneous sclerotherapy is therefore a simple, safe, and effective treatment of testicular vein insufficiency and is suitable for almost 80% of patients with varicoceles.

Adolescent↗
PubMed1987

[Nuclear magnetic resonance tomography: a new imaging diagnostic procedure of the petrous bone and cerebellopontile angle].

Nuclear magnetic resonance imaging (NMRI) is a new technique enabling three dimensional scanning of the petrous bone without ionizing radiation. Contrary to computer tomography NMRI enables visualization of the structures of the inner ear and the cerebello-pontine angle without masking by overprojecting bony structures. The resolution of inflammatory processes and tumors is excellent. NMRI is inferior to CT in demonstrating bony destruction, and is therefore not so effective in the evaluation of glomus tumours. The use of surface coils in combination with a special gradient-zoom-technique allows high resolution imaging. This and Gadolinium-DTPA for enhancement opens new perspectives in the diagnosis of small acoustic neuromas.

Cerebellar Neoplasms↗
PubMed1987

MRI of facial skeleton and parapharyngeal space.

The diagnostic value of magnetic resonance imaging is examined in relation to computed tomography on the basis of 66 patients, who had pathological processes in the midfacial and nasopharyngeal space. The high power of contrast resolution in imaging soft tissue masses and the direct multiplanar capability of magnetic resonance offer advantages over computed tomography in respect of space occupying lesions in the median and lower parts of the craniofacial skull. Lymph nodes of more than 1 cm. in diameter were detected by both modalities. A disadvantage is the poorer detectability of tumour conditioned bone destruction at the base of the skull. In such cases, computed tomography remains the method of choice.

Facial Bones↗