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.

Topography of the cortical motor hand area: prospective study with functional MR imaging and direct motor mapping at surgery.

PURPOSE: To localize the cortical motor hand area with functional magnetic resonance (MR) imaging and electrical stimulation at surgery and to detect changes due to central lesions. MATERIALS AND METHODS: Fast-gradient-echo and functional MR images of the brain were acquired in four healthy volunteers and six patients with tumors in the central region before, during, and after repetitive opening and closing of the hand. Open brain surgery was performed, and the exposed cortex was stimulated. RESULTS: At functional MR imaging, circumscribed changes in signal intensity that correlated in time with the task were seen in the central region of the contralateral brain. In the healthy volunteers, the area of change was spotlike and projected into the posterior bank of the precentral gyrus. In four of the six patients, this area was diffuse and projected into the precentral gyrus. The locations of the cortical hand area as determined with intrasurgical mapping and functional MR imaging were identical. CONCLUSION: Identification of the cortical area responsible for motor hand function was similar with functional MR imaging and with direct stimulation at surgery. A space-occupying lesion can change the cortical representation of motor hand function.

[Diagnosis of fractures of the occipital condyles]. / Diagnostik von Frakturen der Okzipitalkondylen.

The imaging diagnosis of occipital condyle fractures by CT and MRT is reported for cases of 4 patients. Following the conventional X-ray diagnosis of the skull and upper cervical spine, CT proved to be the primary diagnostic method after a skull and brain injury: for all 4 cases we succeeded in detecting the occipital condyle fracture and in determining its size and location by reconstructions (coronal, sagittal, 3-D). In the case of complex accompanying injuries like soft tissue hematomas (cerebral, in the spinal cord, and the soft tissue of the neck) or for the detection of brain stem contusion, MRT had significant advantages. MRT can offer a higher image quality in soft tissue, especially in the spinal cord and the brain.

Glomus tumors of the skull base: combined use of MR angiography and spin-echo imaging.

PURPOSE: To evaluate the use of magnetic resonance (MR) angiography in the diagnosis of glomus tumors of the skull base. MATERIALS AND METHODS: In 40 patients with pulsatile tinnitus, spin-echo (SE) images, single sections, and maximum intensity projections from gradient-echo sequences, including arterial MR angiography and MR venography, were evaluated for tumor detection. Interpretations by two independent observers were correlated with findings from histologic examination, digital subtraction angiography, computed tomography, and clinical follow-up. RESULTS: Glomus tumors were detected near the tympanic plexus (n = 8) and close to the superior (n = 8) and inferior (n = 1) ganglia of the vagus nerve. Sixteen of 18 proved tumors were detected with SE images alone. Although four high-lying jugular bulbs were misinterpreted as tumor due to similar signal intensity, combined evaluation allowed differentiation between tumor and sinusal blood flow in all cases. CONCLUSION: The authors recommend combined SE imaging and MR angiography for ruling out tumor in patients with pulsatile tinnitus.

Dural sinus thrombosis: value of venous MR angiography for diagnosis and follow-up.

OBJECTIVE: The purpose of this study was to determine the value of venous MR angiography as the sole procedure for the diagnosis and follow-up of dural sinus thrombosis. MATERIALS AND METHODS: Forty-two patients with clinical findings suggestive of dural sinus thrombosis were examined with venous MR angiography and spin-echo MR imaging. Maximum-intensity-projection reconstructions and individual sections of the MR angiograms were examined for direct and indirect signs of dural sinus thrombosis by assessing flow signal from the major sinuses, the jugular bulb, upper jugular veins, ascending cortical veins (occlusion or increased flow due to formation of collaterals), diploe (emissary) veins and extracranial veins, and the deep subcortical veins (Galen's and internal cerebral veins). Direct signs of dural sinus thrombosis on MR angiograms included lack of typical high flow signal from a sinus that did not appear aplastic or hypoplastic on single sections from MR angiography and the frayed appearance of the flow signal from a sinus after recanalization. Indirect signs of dural sinus thrombosis included evidence of formation of collaterals, unusually prominent flow signal from deeper medullary veins, cerebral hemorrhage, visualization of emissary veins, and signs of increased intracranial pressure. When available, conventional angiograms were evaluated by analogous criteria as appropriate. Digital subtraction or cut-film angiograms were available for correlation in nine patients. In nine patients, MR angiography was repeated up to eight times during the course of follow-up. The results of MR angiography for all patients were compared with results in 10 control subjects. Confirmation of the diagnosis of dural sinus thrombosis was based either on conventional angiographic findings or on the changes seen in follow-up examinations. RESULTS: Dural sinus thrombosis could be ruled out in 25 of the 42 patients on the basis of clinical and MR angiographic findings. In 17 patients with MR angiographic findings that indicated dural sinus thrombosis, conventional angiography confirmed the diagnosis in nine patients, and changes seen on repeat MR angiograms during follow-up confirmed the diagnosis in nine patients as well (one patient's diagnosis was confirmed by both techniques). Individual frames from two-dimensional fast low-angle shot sequences allowed direct visualization of thrombus. Limited spin-echo sequences as performed here provided inconsistent findings and were insufficient for diagnosis. In the 10 control subjects, attenuation of flow signal was seen in the torcular Herophili in all studies; one subject had a nonpathologic variant of the sinojugular system. CONCLUSION: MR angiography is the technique of choice for diagnostic evaluation and follow-up of dural sinus thrombosis, and it is reliable as the sole examination for this condition. When MR angiographic findings are unremarkable and other abnormalities must be ruled out, routine spin-echo MR imaging should be performed.

[The value of the liver-specific superparamagnetic contrast medium AMI-25 for the detection and differential diagnosis of primary liver tumors versus metastases]. / Wertigkeit des leberspezifischen superparamagnetischen Kontrastmittels AMI-25 für die Detektion und Differential-diagnose lebereigener Tumoren versus Metastasen.

The value of the superparamagnetic contrast medium AMI-25 and its clinical acceptability was investigated in a phase-III-multicenter study. 18 patients with primary and secondary hepatic tumours were studied using T2- and T1-weighted spin-echo sequences, FATSAT sequences and FLASH-2-D-breathold sequences, both before and after intravenous application of AMI-25 (0.2 mmol GE/ml 15 mmol/kg KG in 100 ml 5% glucose infusion), using a 1.5 Tesla MRT (Magnetom 63 SP, Siemens). In 6 patients the MRT findings could be correlated with in vitro results within 30 minutes following surgical resection. In 8 patients a diagnosis of metastases was made. Amongst patients with primary liver tumours (FNH 6 cases, HCC 3 cases, adenomatosis 1 case) 3 of the 10 patients showed more lesions following the injection of contrast; similarly, in 4 patients of the 8 with secondary tumours contrast increased the number of visible lesions. The absence of contrast enhancement separated primary from secondary lesions. Amongst the patients with secondary liver tumours, in vitro correlation always showed more tumours than had been visualised whereas there was exact in vivo/in vitro correlation amongst patients with primary liver tumours.

MRI in pre- and postoperative assessment of tracheal stenosis due to pulmonary artery sling.

OBJECTIVE: To evaluate the potential of MRI in the assessment of tracheal stenosis due to tracheal or vascular malformations, 45 children with severe respiratory distress were examined prospectively during a period of 1 year. Five of these children had tracheal stenosis due to a sling left pulmonary artery (SLPA). MATERIALS AND METHODS: Magnetic resonance examinations of the anesthetized children were performed with a 1.5 T Siemens MR imager using electrocardiographically gated T1-weighted SE sequences in transverse and sagittal slice orientations. Slice thickness was 3 mm and each sequence was repeated after shifting the slice position by 1 mm. Monitoring during the examinations included ECG, oscillatory blood pressure, respiratory rate, and oxygen concentration. Magnetic resonance findings were compared with esophagography, selective pulmonary angiography, bronchoscopy, Doppler sonography, and surgery. All examinations were repeated after surgical therapy to assess the improvement in tracheal stenoses and the patency of the ligated and reimplanted left pulmonary arteries. RESULTS: Magnetic resonance imaging clearly revealed the course of the SLPA and its topographic relationship to the trachea as well as the coexistence of cardiovascular and tracheobronchial or esophageal malformations. The degree and length of tracheal stenoses, which were measured in the pre- and postoperative axial slices and graphically displayed, as well as the angles of the right and left main stem bronchi, could be accurately determined. CONCLUSION: Magnetic resonance imaging in combination with bronchoscopy yielded the necessary and sufficient information for diagnosis and aided the surgeon in planning operative strategy and in postoperative follow-up.

Third cranial nerve palsy caused by gummatous neurosyphilis: MR findings.

The clinical and MR findings in an unusual case of gummatous neurosyphilis are reported. A 44-year-old woman suffering from diplopia and right-sided headaches was admitted. Physical examination and routine laboratory parameters were normal except for a third-nerve palsy. MR images revealed a contrast-enhancing lesion of the upper brain stem and third cranial nerve. Differential diagnosis included neuroma of the third cranial nerve, as well as neurosarcoidosis and other inflammatory processes. Serologic tests and lumbar puncture revealed the presence of active syphilis. After intravenous treatment with penicillin G, follow-up MR examinations showed diminishing size of the lesion with its complete resolution within 3 months.

MR imaging with Gd-DTPA in lesions of the head and neck.

The diagnostic value of MR in the head and neck with special emphasis on the contrast medium Gd-DTPA will be demonstrated. A total of 1,260 patients underwent MR with different pulse sequences plain and with Gd-DTPA. The sequences were analyzed and compared with CT. Due to the different pattern of enhancement the contrast medium helped in differentiating malignant and benign tumors from other processes like cysts and inflammatory changes. Except lesions with small bony erosion and inflammatory changes of the salivary glands MR with Gd-DTPA proved to be diagnostically advantageous in all cases. Gd-DTPA improved the delineation of tumor margins. MR in combination with Gd-DTPA offers a lot of new advantages for diagnosing lesions of the head and neck. However, due to the prolonged examination time and the lack of noninvasiveness the use of Gd-DTPA has to be considered critical for every single area of the head and neck.

Skull base tumors: gadodiamide injection--enhanced MR imaging--drop-out effect in the early enhancement pattern of paragangliomas versus different tumors.

A phase III trial was conducted in 40 patients with known or suspected skull base tumors to evaluate the safety and efficacy of high-dose gadodiamide injection for use as a paramagnetic contrast medium in conventional and dynamic magnetic resonance (MR) imaging. Contrast material enhancement was assessed dynamically with use of a gradient-recalled sequence. The time-intensity curve of selected regions of interest showed a reproducible dropout effect in the form of a dip in the curve during the early enhancement of the sigmoid sinus and jugular bulb; the same phenomenon was observed in all glomus tumors of the skull base, regardless of size or location. In contrast, schwannomas, meningiomas, and a variety of other lesions showed a continuous increase in the time-intensity curve. The drop-out sign, which is probably a result of a paramagnetic phenomenon during the early phase of enhancement, seems to be specific for glomus tumors. High-dose gadodiamide injection may show a specific dynamic pattern for glomus tumors, allowing differentiation from other tumors of the middle and posterior skull base.

MR and MR angiography of Sturge-Weber syndrome.

PURPOSE: To assess the potential of magnetic resonance angiography (MRA) as an adjunct to spin-echo sequences in evaluating the cerebral vascular anomalies seen in Sturge-Weber syndrome. METHODS: Four pediatric patients with Sturge-Weber syndrome were evaluated with conventional MR imaging and with arterial and venous MRA. Resultant images were evaluated for evidence of volume loss, cortical enhancement, vascular anomalies, and enlarged choroid plexus. RESULTS: Venous MRA revealed reduced flow of the transverse sinuses and jugular veins, prominent deep collateral venous system, and a lack of superficial cortical veins. Arterial MRA, performed in all cases, revealed a reduced flow signal from the left middle cerebral artery in one hemiparetic patient and angiomatous changes of high branches of a middle cerebral artery in two patients. CONCLUSION: Arterial and, in particular, venous MRA can be useful adjuncts to standard spin-echo sequences in diagnosing Sturge-Weber syndrome.

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.

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.

[The 31-phosphorus spectroscopy of space-occupying lesions of the salivary glands. The clinical results and differential diagnosis]. / 31Phosphorspektroskopie von Raumforderungen der Speicheldrüsen. Klinische Ergebnisse und Differentialdiagnostik.

In a prospective study, 15 normals and 20 patients with space-occupying lesions of the salivary glands were examined by MRT images and by in vivo 31-phosphorus spectroscopy. The spectra of malignant tumours showed a significant increase in concentration of phosphomonoesters, phosphodiesters and inorganic phosphates when compared with normals. In addition there was an enormous reduction in creatine phosphates. Increased pH values and marked increase in concentration of inorganic phosphates correlated with poorly vascularised necrotic tumour segments. Concentrations of ATP and PCr were similar to normal muscle tissue. High concentrations of PME and PDE correlated directly with the proliferation of tumour cells and were an important marker for the bioenergy and phospholipid metabolism of the growing tumour. Standardised in vivo 31-phosphorus spectroscopy of space-occupying lesions of the salivary glands provides noninvasive prognostic information on the type and behaviour of the lesion and is complementary to clinical and histological findings.

[Magnetic resonance tomography of the hepatobiliary system: indications, limitations and outlook]. / Magnet-Resonanz-Tomographie des hepatobiliären Systems: Indikation, Limitationen und Ausblick.

In a prospective study we examined the diagnostic value of MRI and MR cholangiography (MRC) in patients suffering from hepatobiliary disease. By using hepatobiliary contrast media (Mn-DPDP, Gd-BOPTA), sensitivity and specificity of MRI were significantly increased. In 65 patients we comparatively analyzed the diagnostic results of MRI and MRC versus ultrasound, CT and invasive techniques such as ERCP. We conclude that the use of MRI and MRC improves the diagnostic evaluation of patients with hepatobiliary disease.

MR angiography in children with cerebral neurovascular diseases: findings in 31 cases.

OBJECTIVE: We evaluated the suitability of MR angiography for routine use in children with suspected intracranial vascular disease. SUBJECTS AND METHODS: Thirty-one children, 6 months to 14 years old, with intracranial lesions or clinically suspected vascular malformations were studied prospectively with conventional MR imaging and time-of-flight MR angiography. In nine cases, MR angiographic findings were verified with digital subtraction angiography or conventional angiography. All MR studies were performed on a 1.5-T MR system using a circularly polarized head coil. RESULTS: Arterial MR angiography, performed in 24 cases, revealed congenital abnormalities of the arterial vessels in 20 cases. Vessel stenosis was observed in nine patients, and displacement of intracranial arteries due to tumors could be seen in 10 patients. Seven children had no abnormal findings. Venous MR angiography was performed in seven children, with depiction of sinus thrombosis in six cases. The comparative analysis of MR angiography and digital subtraction angiography showed equivalent results in nine patients; in one patient the degree of stenosis was overestimated with MR angiography. CONCLUSION: MR angiography, when combined with MR imaging, reveals information about soft-tissue and vascular structures in a single setting. At this point, MR angiography can replace invasive conventional angiography or digital subtraction angiography only in selected cases because of software and hardware limitations. Arterial or venous MR angiography can be helpful as an additional scan in MR examinations of children with suspected cerebral neurovascular diseases, and its noninvasive nature makes it well suited for routine use in children.

[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.

[Magnetic resonance tomography and magnetic resonance angiography in lymphangiomatosis]. / Magnetresonanztomographie und Magnetresonanzangiographie der Lymphangiomatose.

Generalised lymphangiomatosis is a rare benign congenital abnormality of the lymphatic vessels with a complex pattern. 3 patients with different types of lymphangiomatosis were studied by MRT and MRA and histopathologically. All patients had multiple organ involvement in the abdomen, the skeleton and the skull. The basis in each case was lymphangiomatosis of capillary-cavernous, cystic or cavernous type. The results of MRT and MRA in diagnosing splenic, vascular and skeletal changes correlated accurately with operative findings and with the histopathological classification. In summary, MRT combined with MRA and using paramagnetic contrast media are the diagnostic methods of choice for the investigation of generalised lymphangiomatosis with multiple organ involvement.

[The proton MR spectroscopy of intracranial tumors. The differential diagnostic aspects for gliomas, metastases and meningiomas]. / Protonen-MR-Spektroskopie intrakranieller Tumoren. Differentialdiagnostische Aspekte für Gliome, Metastasen und Meningeome.

Twenty-two patients with intracranial tumours were examined by MR images and in vivo proton-MR-spectroscopy. The changes of relative concentrations of NAA, PCr/Cr, Cho, and Ins were measured spectroscopically and the amount of these metabolites were related to different tumour groups. Analysis of the results has shown that the spectra from all the tumours differed from normal spectra. All cerebral tumours showed marked reduction of the Pcr/Cho quotient and the NAA/Cho quotient was also reduced. The Ins/Cho quotient for meningiomas and metastases was also lower than in normals; in gliomas of low malignancy the quotient was slightly raised and in gliomas of greater malignancy it was significantly higher than normal. The spectra of cerebral metastases showed unusual high lipid signals of 0.9 ppm and 1.25 ppm. The only common feature for meningiomas was marked reduction of NAA concentration. In summary, localised in vivo proton-MR-spectroscopy can be used clinically to obtain valuable information for the differential diagnosis of gliomas and intracerebral metastases.