The efficacy of anterior repositioning splint therapy studied by magnetic resonance imaging.

Magnetic resonance images (MRIs) were obtained of 52 temporomandibular joints (TMJs) of 30 patients with TMJ disease, before insertion of an anterior repositioning splint. Ten TMJs showed a normal disc-condyle relationship. Pathological findings were partial or complete anterior disc displacement with disc reduction (n = 18), without (n = 7), or with partial reduction (n = 4) or non-reducing joints combined with osteoarthrosis (n = 13). Associated clinical findings were joint clicking, painful TMJ movements with or without condyle limitation, deviation, or crepitus. The clinical evaluation when compared with the MRIs correlated in 75 per cent of cases. Immediate post-insertion MRIs showed recapture of discs with a protrusive splint in 15 out of 18 reducing displacements. Recapture of the disc was seen in only two out of four joints with anterior disc displacement with partial disc reduction. There was no recapture in non-reducing joints. In severe cases of internal derangement with a wide range of disc displacement combined with changes of the osseous joint surfaces, the recapturing of the articular disc with an anterior repositioning appliance was unsuccessful (0 of 13). The follow-up for pain relief after one week showed a significant reduction of symptoms, despite the fact that recapture of the dislocated disc occurred in only 17 of the 42 pathological TMJs. The possibility for disc recapture depends on the disc-condyle position and configuration, the integrity of the posterior attachment, and the degree of degenerative changes of the intra-articular structures, such as osteophytosis, condylar erosion, or flattening of the articular disc. This diagnostic information influences the method of treatment of TMJ disorders. In non-reducing joints or in the later stages of internal derangement of the TMJ, it is not possible to achieve a normal disc-condyle relationship using protrusive splints.

Functional magnetic resonance imaging of temporomandibular joint disorders.

Fifty-eight temporomandibular joints (TMJs) from 40 patients with TMJ-related symptoms were examined by means of magnetic resonance scans with modified gradient echo sequences and a special double coil. This technique yielded a good spatial resolution of the intra-articular soft tissues, especially the articular disc and the bone structure of the TMJ. In combination with an incremental jaw opener, the disc-condyle complex was analysed in various closed and open mouth positions, depending on the clinical examination. Open mouth movement with differentiation of disc-condyle rotational and translation movement was demonstrated. Disturbances of TMJ motion showed interrupted condylar translation combined with mandibular deviation during open mouth movement (n = 8/58). Early phases of internal derangement of the TMJ with partial anterior disc displacement with (n = 12/58) or without (n = 2/58) reduction, total anterior disc displacement without reduction (n = 10/58), disc deformation (n = 10/58), disc adhesion (n = 2/58), condylar hypermobility (n = 6/58), condylar displacement (n = 8/58), and late phases of internal derangement of the TMJ with osteoarthrosis (n = 14/58) were clearly identified. Bilateral TMJ disorder was found in 72.5 per cent of the patients. By using motion-adapted, semi-dynamic magnetic resonance imaging (MRI), it is possible to improve the understanding of the complexity of TMJ movements.

[Detection of bone metastases in patients with neuroendocrine gastrointestinal tumors]. / Zur Detektion von Knochenmetastasen bei Patienten mit neuroendokrinen gastrointestinalen Tumoren.

INTRODUCTION: In patients with neuroendocrine gastrointestinal tumors and liver metastases, but without known extrahepatic manifestations, liver transplantation may be indicated as curativ or "long-term-palliativ" therapy. For these patients the absence of bone lesions is mandatory. METHODS: 4 patients with a histologically proven neuroendocrine tumor were examined in order to exclude further metastases. We compared the diagnostic value of somatostatin-receptor-scintigraphy (SRS), X-ray, 99mTc-DPD-scintigraphy, CT and MRI. RESULTS: In all 4 patients bone metastases could be detected using SRS, CT und MRT. In one case MRI proved multiple infiltrations, while SRS showed only a solitary, focal lesion. 99mTc-DPD-scintigraphy was positive in 3 cases, X-ray in 1 case. CONCLUSION: As a diagnostic strategy we initially recommend somatostatin-receptor-scintigraphy. When locating suspect areas in SRS, MRI should be the method of choice for the exact evaluation of malignant bone infiltrations. A CT-guided biopsy is necessary to gain histological information.

Contrast-enhanced power Doppler sonography: improved detection of characteristic flow patterns in focal liver lesions.

PURPOSE: The aim of this study was to evaluate whether intravenous injection of an ultrasound contrast agent aids in the visualization of focal liver lesions on power Doppler images. METHODS: Fifty patients with focal liver lesions were studied by B-mode and power Doppler sonography before and after intravenous injection of the contrast agent Levovist (galactose-based microbubbles; 10 ml of a concentration of 300 mg/ml). Thirty-two patients had malignant liver lesions (19 metastases, 12 hepatocellular carcinomas, 1 cholangiocellular carcinoma), while 18 had benign lesions (12 hemangiomas, 2 focal nodular hyperplasias, 4 others). RESULTS: After contrast medium injection, the number of lesions with no intralesional flow dropped from 18 to 9. Flow signal intensity was rated subjectively as marked on contrast-enhanced images in 17 patients; only 4 patients had marked flow on precontrast images. On precontrast studies, central flow in 10 lesions and peripheral flow in 29 lesions could be observed. After enhancement, the numbers increased to 18 and 34 lesions, respectively. CONCLUSIONS: On power Doppler images, a greater number of intratumoral vessels are seen in focal liver lesions after contrast medium administration.

[Dose distribution in conventional CT and spiral CT and on the topic of dose reduction with spiral CT]. / Zur Dosisverteilung in konventioneller CT und Spiral-CT und zur Frage der Dosisreduktion mit Spiral-CT.

OBJECTIVE: To compare spiral CT with conventional CT with regard to the dose distribution in the irradiated body and to examine when an increase in the table feed in spiral CT leads to a dose reduction compared with conventional CT. METHODS: In order to show the dose distribution, films were exposed in an acrylic phantom. The nominal slice thickness was 5 mm; the slice distance in conventional CT was 5 and 10 mm; the table feed in spiral CT was 5 and 10 mm per rotation (pitch 1 and 2). The integral doses delivered in spiral CT and conventional CT were related to the table feed per rotation or slice distance, respectively, and were compared arithmetically with each other. RESULTS: Spiral CT showed reduced dose fluctuations in axial direction compared with conventional CT. Only in conventional CT with a slice distance of 5 mm did the axial dose distribution show relative dose peaks near the rotation axis. The longer the body region to be examined is, the less table feed is necessary in spiral CT for a dose reduction. From a length of 15 times the slice thickness, a pitch of > 1.1 leads to a reduction of the integral dose compared with conventional CT. CONCLUSIONS: The continuous table feed in spiral CT results in evenly distributed axial dose distributions compared with the discontinuous scanning in conventional CT. The spiral technique can give an important contribution to dose reduction in CT.

[Doppler sonographic monitoring control of perfusion of hepatocellular carcinoma after arterial chemoembolization]. / Dopplersonographische Verlaufskontrolle der Perfusion hepatozellulärer Karzinome nach arterieller Chemoembolisation.

INTRODUCTION: 22 patients with hepato-cellular carcinomas were examined sonographically before and after intra-arterial chemo-embolisation. The aim was to evaluate different techniques for judging tumour morphology and for assessing changes in perfusion. MATERIAL AND METHODS: The morphological appearances and perfusion changes were analysed by means of colour coded duplex sonography and power Doppler sonography before and after intravenous contrast medium. Pulsatility (Pl) and resistance index (RI) were used as quantitative parameters for judging changes in perfusion. RESULTS: In 13 patients intra-tumoral arteries were identified by duplex sonography and in four patients only by the power Doppler procedure. In three patients arterial vessels could only be identified after intravenous contrast. In 9 patients it was possible to document a reduction in arterial perfusion following embolisation. The indices calculated from these findings gave no prognostic indication. DISCUSSION: The methods described give information concerning changes in perfusion of a tumour following chemo-embolisation and, in conjunction with CT and clinical findings, provide indications for further tumour embolisation.

[Vascularization patterns in focal liver lesions: comparison of plain and signal-enhanced amplitude-modulated color duplex ultrasonography]. / Vaskularisationsmuster in fokalen Leberläsionen: Vergleich der nativen und signalverstärkten amplitudenmodulierten Farbduplexsonographie.

PURPOSE: Morphology of focal liver lesions was studied by power Doppler. Plain images and images after i.v. application of galactose-based microbubbles (Levovist, Schering AG) were compared. METHODS: 21 patients with focal liver lesions were studied by power Doppler before and after application of the signal enhancer. RESULTS: In lesions that showed short pulsations in plain studies, vascular structures were visible after application of the signal enhancer. In hepatocellular carcinomas, multiple arteries with small diameter became visible. Peripheral veins were detected in metastases. A large feeding artery was detected in 1/2 haemangiomas with flow and in a focal nodular hyperplasia. CONCLUSION: In comparison to plain amplitude-modulated colour-coded duplex ultrasound, vascular patterns of focal liver lesions were more clearly visible after injection of a signal-enhancer.

[HIV-associated cysts of the parotid glands. An histomorphologic and magnetic resonance tomography study of formal pathogenesis]. / HIV-assoziierte Zysten der Ohrspeicheldrüsen. Eine histomorphologische und magnetresonanztomographische Untersuchung zur formalen Pathogenese.

BACKGROUND: Multiple and bilateral parotid Lymphoepithelial cysts (LEC) are encountered in 3-6% of HIV-infected patients. The formal pathogenesis of LEC is controversial. They are thought to develop from embryological salivary gland inclusions in intraparotid lymphnodes. METHODS: Seventeen operative parotid specimens from HIV-infected patients were examined histologically and immunohistologically. Findings of magnetic resonance imaging (MRI) were correlated with the histological results. RESULTS: A continuous spectrum of a lymphoepithelial salivary gland lesion is found, developing initially from a lymphoid infiltration of salivary lobules to lymphoepithelial duct lesions with cystic dilatation up to large ductal cysts (diameter up to 3.5 cm) with highgrade parenchymal atrophy. The ductal and cystic lesions demonstrate an intense basal cell hyperplasia without participation of myoepithelial cells. The MRI findings indicate involvement of the entire tissue of both parotid glands. CONCLUSIONS: The preferred hypothesis of a development of HIV-associated Lymphoepithelial cysts from preexisting salivary lymphnode inclusions cannot be verified. Our results demonstrate a continuous development of the cysts from a Sjögren-like cystic lymphoepithelial lesion of parotid glands. The enormous cystic dilatation of the duct lesions presumably is a consequence of ductal obstruction through basal cell hyperplasia of striated ducts and intense intraglandular lymphofollicular hyperplasia.

[Skull injury in childhood: comparison of ultrasonography with conventional X-rays and computerized tomography]. / Schädeltrauma im Kindesalter: Vergleich der Sonographie mit konventionellen Röntgenaufnahmen und der Computertomographie.

PURPOSE: The purpose of our study was to compare the value of ultrasound, conventional x-ray diagnosis and CT in detecting skull fractures and intracranial haemorrhage in children suffering from a head injury. MATERIAL AND METHODS: We examined 210 children who had a head injury. In all cases the calvarium was investigated by ultrasound using a 7.0 MHz linear transducer. In children with an open fontanel (n = 190) the cerebrum was screened additionally by ultrasound following a standard protocol. The sonographic findings were correlated to the x-ray examination (n = 21) and CT (n = 13). RESULTS: Ultrasound enabled diagnosis of linear calvarial fractures (n = 29), depressed fractures (n = 6) and intracranial haemorrhage (n = 8). X-Ray and CT examination confirmed the diagnosis of linear calvarial fractures in 16 cases, of depressed fractures in 6 cases. CT confirmed the sonographic diagnosis of intracranial haemorrhage in 8 cases. CONCLUSION: Ultrasound as a primary method can replace the conventional x-ray in detecting calvarial fracture and posttraumatic sequelae. Additional CT examination depends on the sonographic and neurological status.

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.

[Perioperative evaluation of internal carotid artery stenoses: value of multislab MR angiography]. / Perioperative Evaluierung von A.-carotis-interna-Stenosen: Stellenwert der Multislab-MR-Angiographie.

PURPOSE: Evaluation of the diagnostic potential of high resolution multislab 3D-TOF-magnetic resonance angiography (MRA) in the pre- and postoperative assessment of carotid artery stenosis in comparison to conventional angiography. METHODS: 120 Patients were evaluated with MRA and DSA prior to carotid endarterectomy (CEA). Additionally 26 patients underwent MRA after CEA. All MRA examinations were carried out on a 1.5 T MR-unit (Siemens Magnetom SP63) using a Helmholtz surface coil. For the visualization of the vascular structures in the head and neck region, flow compensated GE-sequences were employed. Both original MRA data set and MIP angiograms were included in the evaluation. The determination of the extent of stenoses was performed according to the recommendation of NASCET. RESULTS: In 195 (92.9%) of 210 cases included in the review MRA revealed the same results as DSA (grade I+II: 114, grade III: 24, grade IV: 44, grade V: 13). None of the cases showed a deviation higher than one grade. The sensitivity and specificity of hemodynamic relevant stenoses (> 60%) was 0.964 respectively 0.952. 23 out of 26 patients with postoperative follow-up examination revealed regular reperfusion of the former affected internal carotid artery. The remaining 3 patients showed a restenosis of the operated vessel (n = 2) and a reocclusion of the ICA after surgery (n = 1). MRA proofed to be an accurate and reliable method for the perioperative evaluation of vascular structures in the head and neck region. Despite of some drawbacks MRA reached a high accuracy in the diagnostic imaging before and after CEA. MRA is accurate and useful in screening carotid artery diseases. The indication of MRA employment therefore not only covers the screening of vascular structures but also includes pre- and postoperative evaluation of vascular stenoses.

[MRI of focal liver lesions using a 1.5 turbo-spin-echo technique compared with spin-echo technique]. / MRT fokaler Leberläsionen bei 1,5T Turbo-Spinecho-im Vergleich mit derSpinecho-Technik.

AIM: The aim of our study was to evaluate a T2-weighted turbo-spinecho sequence in comparison to a T2-weighted spinecho sequence in imaging focal liver lesions. METHODS: In our study 35 patients with suspected focal liver lesions were examined. Standardised imaging protocol included a conventional T2-weighted SE sequence (TR/TE = 2000/90/45, acquisition time = 10.20) as well as a T2-weighted TSE sequence (TR/TE = 4700/90, acquisition time = 6.33). Calculation of S/N and C/N ratio as a basis of quantitative evaluation was done using standard methods. A diagnostic score was implemented to enable qualitative assessment. RESULTS: In 7% (n = 2) the TSE sequence enabled detection of further liver lesions showing a size of less than 1 cm in diameter. Comparing anatomical details the TSE sequence was superior. S/N and C/N ratio of anatomic and pathologic structures of the TSE sequence were higher compared to results of the SE sequence. CONCLUSION: Our results indicate that the T2-weighted turbo-spinecho sequence is well appropriate for imaging focal liver lesions, and leads to reduction of imaging time.

[CT angiography in carotid stenosis. Diagnostic value compared to color-coded duplex ultrasonography and MR angiography]. / CT-Angiographie bei Karotisstenosen. Diagnostischer Wert im Vergleich zur farbkodierten Duplexsonographie und MR-Angiographie.

PURPOSE: To evaluate the accuracy of different diagnostic methods for the visualization of the carotid arteries and their pathological changes in order to avoid invasive angiography whenever surgery was considered. MATERIAL AND METHODS: 24 patients with clinically suspected stenosis or occlusion of the carotid arteries were prospectively examined via CT angiography. MR angiography and colour-coded duplex sonography (ccds) to evaluate the degree of stenosis and the extent of calcification. RESULTS: In 36 cases stenoses of different extent could be documented with CT angiography, 33 cases were found using colour-coded duplex sonography and MRA. Sonography could not prove mild stenoses (< 30%), and in two patients with sonographically suspected total occlusion vessel perfusion was documented via CT angiography. MR angiography led to a overestimation in patients with high-grade stenosis compared to the degree of stenosis obtained via ccds and CTA. With regard to the diagnosis of calcification MIP, reconstructions after CT examination showed best correlation to the plain CT slices referring to length (94.6%) and thickness (89.2%). CONCLUSION: CTA with MIP reconstructions is an excellent screening method and, in combination with ccds, CT angiography may replace DSA before surgery or intervention.

[The value of MRT in primary extramedullary plasmacytoma involvement of the head-neck area]. / Die Wertigkeit der MRT beim primär extramedullären Plasmozytombefall in der Kopf-Hals-Region.

Six patients with a primary extramedullary plasmocytoma in the head and neck were examined using MR imaging. The morphological appearance of these lesions was described to support the radiologist in the differential diagnosis of this rare lesion. All tumours appeared as oval-shaped and sharply delineated without any signs of infiltration. After contrast media application a distinct central inhomogeneity could be proved in all cases. Furthermore, demoscopical, clinical and therapeutical problems were discussed based on the literature.

Cystic masses in the floor of the mouth: value of MR imaging in planning surgery.

OBJECTIVE: The purpose of this study was to determine the value of preoperative MR imaging for planning the best surgical approach for excising cystic masses in the floor of the mouth. In addition, different sequences and slice orientations were compared in order to develop a standard MR examination technique for this purpose. SUBJECTS AND METHODS: Eleven patients with cystic masses in the floor of the mouth were prospectively examined with MR imaging after palpation and sonography. The imaging protocol included T1- and T2-weighted spin-echo sequences, both unenhanced and contrast enhanced. The exact topographic relationship of these cysts to the surrounding muscles and the value of different MR techniques were analyzed. RESULTS: The mylohyoid muscle, which serves as a key structure in determining the exact position of a cystic mass, was visualized in all cases. T2-weighted images facilitated the primary diagnosis of cystic lesions, whereas T1-weighted images allowed the best visualization of anatomic details. Use of gadopentetate dimeglumine did not provide significant diagnostic information. Coronal and axial slices provided the best visualization of the topographic relationship of cyst and muscles. Sagittal slices were helpful only for midline lesions. In two cases, the choice between the intraoral and the cervical surgical approach was altered by MR imaging findings. CONCLUSION: MR imaging facilitates exact visualization of the location and extent of cystic lesions in the floor of the mouth and is useful for determining their relationship to the surrounding muscles. We conclude that MR imaging is an important adjunct to palpation and sonography in planning the best surgical approach.

[The clinical value of magnetic resonance tomography in cystic space-occupying lesions of the mouth floor]. / Klinische Wertigkeit der Magnetresonanztomographie bei zystischen Raumforderungen des Mundbodens.

11 patients with cystic lesions of the floor of the mouth were examined by MR imaging. Coronal slices provided an optimal visualisation of the lesions, but axial and sagittal slices added important information with regard to the exact topographic relationship between tumour and muscles. In particular, the mylohyoid muscle could be defined as a key structure. T1-weighted sequences enabled best visualisation of anatomic details, whereas T2-weighted sequences facilitated the primary diagnosis of cystic lesions. The contrast agent Gd-DTPA did not add information of significant diagnostic value. Our results indicate that MRI allows an exact visualisation of location and extent of cystic lesions and their relationship to surrounding muscles. We conclude that MRI is of high value in planning the operative strategy.

[NMR tomographic diagnosis with Gd-DTPA in HIV-associated diseases in the head-neck area]. / Kernspintomographische Diagnostik mit Gd-DTPA bei HIV-assoziierten Erkrankungen im Kopf-Hals-Bereich.

In a prospective study 21 patients suffering from HIV-1 infection underwent MR imaging. The following tumours were found: eight Kaposi's sarcomas, four lymphomas, two squamous-cell carcinomas, and three cases of lymphoid hyperplasia. Furthermore, three cases with lymphoepithelial cysts and one case of inflammatory changes of the parotid glands were studied. Optimal diagnostic results were obtained by using T1- and T2-weighted sequences plain and Gd-DTPA enhanced. Different signal intensities enabled the differentiation of lesions such as inflammation, lymphomas and lymphoid hyperplasia. Besides clinical examination modalities, MR imaging proves to be an important tool in investigating solid, cystic or inflamed processes in HIV-positive patients in the head and neck area.

[Magnetic resonance tomography of the oropharynx and oral cavity with Gd-DTPA. An optimized study technic and its diagnostic value]. / Kernspintomographie des Oropharynx und des Cavum oris mit Gd-DTPA. Optimierte Untersuchungstechnik und diagnostische Wertigkeit.

In the evaluation of space-occupying lesions of the oropharynx it is necessary to perform modern imaging methods, such as magnetic resonance imaging additionally to clinical and endoscopical methods. 126 patients were examined using T1-weighted (TR = 500 ms, TE = 25 ms) and T2-weighted (TR = 3000 ms, TE = 25/90 ms) spin-echo-sequences before and after i.v. application of Gd-DTPA. Superficially growing lesions of stage T1 could not be delineated from isointense mucosa. The preoperative staging of T2-T4 lesions can be markedly improved by using T1- and T2-weighted sequences in combination with Gd-DTPA. MR imaging with Gd-DTPA is recommended as the primary diagnostic tool for diagnosing lesions in the region of the oropharynx.