Magnetic resonance (MR) imaging in the open- and closed-mouth positions is the method of choice for visualizing the temporomandibular joint (TMJ). To analyze the TMJ in response to various degrees of mouth opening, the authors constructed a hydraulic incremental jaw opener. This apparatus enables obtaining of reproducible and stable positions of TMJ articulation. With modified gradient pulse sequences, the technique yields good spatial resolution of joint anatomy, including that of the articular disk. The application of a cine program allows cinematographic display of TMJ motion, which in conjunction with static open- and closed-mouth views can be useful in the diagnosis of TMJ dysfunction. The authors used the incremental jaw opener to examine the disk-condyle complex at each open-mouth position, with particular attention to extreme open-mouth positions.

Equipment Design↗

PubMedDate not supplied

Mn-DPDP enhancement patterns of hepatocellular lesions on MR images.

The recently developed paramagnetic hepatobiliary contrast agent manganese dipyridoxyl diphosphate (DPDP) was evaluated in eight patients. Pathologic diagnoses included five hepatocellular carcinomas, two cirrhoses, and one focal nodular hyperplasia. T1-weighted spin-echo and gradient-echo images were obtained after intravenous injection of 5 or 10 mumol/kg Mn-DPDP; these were compared with unenhanced T1-weighted spin-echo and gradient-echo images and T2-weighted spin-echo images. In all patients with lesions of hepatocellular origin, focal areas of increased enhancement were seen in the lesions after administration of Mn-DPDP. In the cirrhotic livers, these areas corresponded to foci of hepatic regeneration. In all patients, the signal-to-noise ratio in normal liver tissue increased significantly after injection of Mn-DPDP. Signal intensity in the six primary liver tumors was further increased, so that they appeared hyperintense relative to surrounding liver tissue on all T1-weighted images. Conspicuity and demarcation of all lesions were improved on Mn-DPDP-enhanced images.

Adult↗

PubMedDate not supplied

Three-dimensional MR reconstruction images of skull base tumors.

Forty-eight patients with skull base tumors were evaluated prospectively with T1-weighted spin-echo two-dimensional (2D) magnetic resonance (MR) sequences, a three-dimensional (3D) MR TurboFLASH (fast low-angle shot) sequence, and a 3D reconstruction window technique. All patients underwent surgery with histopathologic correlation, and the three MR imaging techniques were compared to assess representation of tumor margins and the topographic relationship of tumor to surrounding tissue and adjacent vasculature. The best results were obtained with standard 2D spin-echo sequences after administration of the paramagnetic contrast agent gadopentetate dimeglumine. The 2D MR sequences gave the highest contrast-to-noise ratios, with decreasing values for 3D sequences and 3D reconstructions, respectively. Nevertheless, 3D MR imaging, by virtue of its good representation of adjacent structures, aided surgeons in planning surgical intervention. This study presents the technical features of 3D imaging of the skull base, the choices involved in its implementation, and its potential clinical applications.

Brain Neoplasms↗

PubMedDate not supplied

Experiences with a small selfmade RIS in the University Hospital of Munich, and future plans.

Explore the source record for details and available documents.

Forecasting↗

PubMedDate not supplied

31P-spectroscopy of head and neck tumors--surface coil technique.

Comparative phosphorus-31 magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) of 15 patients with superficial masses such as sarcoma, carcinoma, lymphoma, adenoma, and tuberculosis revealed significant increased concentrations of phosphomonoester, phosphodiester, and inorganic phosphorus in the lesion, whereas the concentration of the phosphocreatine was lower in comparison to muscle tissue. In nearly all masses, pH showed a slight alkaline shift. Existence of necrotic regions detected by MRI was marked by an increase of inorganic phosphorous in the spectra. Tumor growth was characterized by raised concentrations of phosphomonoester. Follow-up studies in a case of lymphoma showed a six-fold decrease of the tumor, while the spectra indicated a gradual transition of tumor values to muscle values. A follow-up study during irradiation of a squamous cell carcinoma revealed a considerable decrease of inorganic phosphate and a subsequent increase of phosphodiester.

Adult↗

PubMedDate not supplied

MR imaging of the breast using gadolinium-DTPA.

In a preliminary study 20 patients underwent breast examinations by magnetic resonance (MR) imaging without and with Gd-DTPA as contrast medium. All carcinomas enhanced, whereas dysplastic tissue enhanced slightly or not at all. Significant additional diagnostic information was available on the Gd-DTPA examinations in at least four of 20 cases compared with MR without contrast medium and X-ray mammography. Our preliminary results indicate that MR imaging of breast using Gd-DTPA may be helpful for the evaluation of dense breasts and the differentiation of dysplasia and scar tissue from carcinoma.

Biopsy↗

PubMedDate not supplied

Comparison of CT with MR imaging of endobronchial tumors.

Twenty-nine patients suspected of having an endobronchial mass were examined by magnetic resonance (MR) and CT. Seventy-nine pathological and 319 normal bronchi were confirmed by bronchoscopy and/or operation in these patients. The studies were evaluated by two observers (A and B): By MR, only 72% (A) or 71% (B) of the pathological and 45% (A) or 43% (B) of the normal bronchi, respectively, were visualized. Computed tomography identified all pathological and 97% of the normal bronchi (A and B). Therefore, comparison between MR and CT was based only on those bronchi that were adequately visualized on MR as well as CT. For these bronchi the sensitivity of MR was 88% (A) or 77% (B) and of CT 96% (A) and 93% (B). Specificity was 92% (A) and 94% (B) for MR and 97% (A and B) for CT. At the present stage of development CT proved to be superior to MR in demonstrating endobronchial lesions.

Adenocarcinoma↗

PubMedDate not supplied

MR imaging of the oropharynx and tongue: comparison of plain and Gd-DTPA studies.

The effect of intravenously administered gadolinium-diethylene-triamine pentaacetic acid (Gd-DTPA) on signal intensity in comparison to plain noncontrast imaging was analyzed. Sixty-one patients with diseases of the oropharynx and tongue base were examined using multiplanar magnetic resonance (MR) imaging. The contrast medium Gd-DTPA was administered in 26 cases. Thirty-eight patients also underwent CT. Forty-one patients had surgery and pathological verification. Plain MR imaging was equal or superior to CT in all except one patient. Marked contrast enhancement produced by Gd-DTPA was observed in carcinomas, sarcomas, inflamed salivary glands, and in normal pharyngeal mucosa. The usefulness of Gd-DTPA may be increased by measuring the enhancement in signal intensity versus time to allow a better differentiation of histological features.

Gadolinium↗