[Juxta-facet cysts: magnetic resonance tomography diagnosis]. / Juxtafacettenzysten: Magnetresonanztomographische Diagnostik.

The term juxta-facet cyst summarizes synovial cysts, arising from degenerated facet joints and ganglion cysts, developing from mucinous degeneration of periarticular connective tissue. Most juxta-facet cysts are observed at the L4/5 level, which generally has the most motion within the lumbar spine. In this retrospective study 31 juxta-facet cysts in 28 patients were detected within 2898 lumbar MRI studies over a 2-year period (frequency 1%). 24 patients complained of back and lower extremity pain, the other 4 patients had unilateral back pain. In 7 cases radicular symptoms were observed, in 6 patients a neurogenic claudication. In 78% of the patients juxta-facet cysts were responsible for clinical symptoms. MRI is the diagnostic imaging technique of choice due to a high sensitivity. The juxta-facet cysts were located extradural, laterally to the thecal sack and adjacent to a degenerated facet joint. In all but one cases the cysts showed a signal intensity equivalent to cerebrospinal fluid. T2-weighted pulse sequences in sagittal orientation were very useful in delineating the hypointense cyst wall. In 1 patient with acute radicular pain MRI demonstrated a subacute hemorrhage within a juxta-facet cyst. Calcifications and gas-filled cysts can be missed with MRI, but will be demonstrated by computed tomography. 45% of the juxta-facet cysts showed an enhancement of the cyst wall after injection of Gd-DTPA. Spontaneous reduction or resolution of the cyst may occur during rest. Injection of corticosteroids into the corresponding facet joint may reduce the inflammatory process and resolve the symptoms in up to 70%. Surgical resection of the cyst is indicated in case of intractable pain and significant neurologic deficit and generally produces good relief from radicular symptoms.

Fluorine-18-FDG PET and iodine-123-IMT SPECT in the evaluation of brain tumors.

UNLABELLED: The high glucose utilization of normal gray matter limits the detection of brain tumor tissue by PET using 18F-fluorodeoxyglucose (FDG). The aim of this study was to evaluate whether the examination of amino acid transport with the SPECT tracer 123l-alpha-methyl-L-tyrosine (IMT) allows better identification of tumor tissue than FDG-PET. METHODS: Nineteen patients (16 with gliomas, 3 with nontumorous lesions) were included in the study. Two independent observers classified PET and SPECT images as positive or negative for tumor tissue and defined the extent of tumor with regions of interest. Tracer uptake of FDG and IMT was quantified by calculating the tumor uptake relative to contralateral gray and white matter. RESULTS: SPECT studies were interpreted concordantly in 18 patients (kappa = 0.77) and all tumors were identified by both observers. PET studies were interpreted discordantly in 4 patients (kappa = 0.52) and only 10 tumors were identified by both observers, interobserver variability in definition of tumor extent was significantly lower in the IMT-SPECT than in the FDG-PET studies (p = 0.03). Mean tumor uptake relative to gray and white matter was 1.93 +/- 0.42 and 2.25 +/- 0.46 for IMT and 0.93 +/- 0.32 and 1.61 +/- 0.52 for FDG. All tumor uptake ratios were significantly (p < 0.01) higher for IMT than FDG, even when only glioblastomas were analyzed. No significant correlation was observed between the various uptake ratios of FDG and IMT. CONCLUSION: Despite the lower resolution and lower sensitivity of SPECT compared with PET, IMT-SPECT was clearly superior to FDG-PET in the detection and delineation of tumor tissue.

[Osteomyelitis sicca in Crohn disease--coincidence or extraintestinal manifestation?]. / Osteomyelitis sicca bei Morbus Crohn--Koinzidenz oder extraintestinale Manifestation?

In patients with Crohn's disease arthritis of the large joints, osteomalacia, osteoporosis and aseptic bone necrosis as a consequence of malabsorption and glucocorticoid intake may occur. The case of a patient with long-standing Crohn's disease is presented who subsequently developed abacterial osteomyelitis of the jaw ("osteomyelitis sicca"). The symptoms of the osteomyelitis improved under immuno-suppressive therapy. Because the etiopathogenetic concepts for Crohn's disease and osteomyelitis sicca are similar, the latter could be a rare extraintestinal manifestation in Crohn's disease, not described previously.

[A comparison of plain film, axial CT, 2D and 3D reconstructions in unstable spinal injuries following surgery]. / Vergleich von Ubersichtsbild, axialer CT, 2D- und 3D-Rekonstruktion bei instabilen operierten Wirbelsäulenverletzungen.

During a period of 18 months about 70 patients suffering from an unstable spinal injury were operated in the surgical department of our clinic. In 50 of these patients it was possible to correlate the results of preoperative radiography and CT with the operative findings. Several cases of distraction instability in the dorsal column had not been recognised in the preoperative radiologic evaluation. Therefore the rationale of this study was the question as to whether modern CT technology can help to avoid such wrong diagnoses. For that purpose radiographs, axial CT-scans of 2 mm thickness or less, sagittal and coronal 2D and (in 35 cases) 3D reconstructions were re-evaluated step by step by a specifically trained radiologist without knowing the operative findings. 15 additional lesions out of 28 were demonstrated and specifically classified as distraction instabilities of the dorsal column using the improved CT technology.

[The MRT criteria for the differentiation of "pseudotumorous" lesions from bone sarcomas of the extremities]. / MRT-Kriterien zur Differenzierung "pseudotumoröser" Läsionen von Knochensarkomen der Extremitäten.

The MRT scans of 57 patients with Ewing or osteosarcomas and 34 patients with haematogenous osteomyelitis or periostitis/stress fractures were examined in order to determine whether a distinction between benign or malignant lesions is possible. Four criteria were evaluated: the margin of the bone marrow component; intensity and homogeneity of the T1 weighted signal in the bone marrow; presence of an extraosseous structured soft tissue mass and/or soft tissue edema. It was found that central osteosarcomas and Ewing's sarcomas reduced signal intensity of the marrow to become muscle-isointense with a well-defined margin. In acute haematogenous osteomyelitis and periostitis/stress fracture the marrow lesion was not sharply demarcated. In contrast to patients with bone sarcomas, only one case of osteomyelitis showed an extraosseous structured soft tissue mass. On the basis of these findings we believe that acute haematogenous osteomyelitis can be distinguished with high degree of accuracy from Ewing's sarcoma and central osteosarcomas.

[Computed tomographic assessment of breathing-induced "pseudo" pneumoperitoneum]. / Computertomographische Beurteilung des beatmungsinduzierten "Pseudo"-Pneumoperitoneums.

The differentiation between a "pseudo" pneumoperitoneum and a pneumoperitoneum due to a perforation may be difficult in unconscious or ventilated patients. The use of CT for differentiating between extraperitoneal and intraperitoneal air is demonstrated by three examples in whom air below the diaphragm was shown by conventional radiographs. CT can prove the extraperitoneal position of an air crescent below the diaphragm in cases of "pseudo" pneumoperitoneum. CT will also show that extraperitoneal air does not rise in the way that true peritoneal air will do when the patient is supine. In this position the viscera therefore do not fall backwards in the presence of a "pseudo" pneumoperitoneum.

[Formation of a neosphincter following loss of function of the upper esophageal sphincter]. / Ausbildung eines Neosphinkters nach Funktionsverlust des oberen Osophagussphinkters (OOS).

In order to prevent aspiration following loss of function of the UOS a new sphincter may develop. This usually arises from the oblique part of the cricopharyngeus muscle and the caudal part of the thyropharyngeus muscle and it is functionally independent of the UOS. We examined 40 patients by cinematography: these included 30 patients with a Zenker's diverticulum, 8 patients following myotomy of the UOS and 2 patients with tumour infiltration of the UOS. The new sphincter could be demonstrated in 70% of patients with Zenker's diverticulum: its function depended on the size and localisation of the diverticulum. Following myotomy of the UOS the new sphincter is usually only just perceptible. In one case there was, however, marked dyskinesia, requiring further myotomy.

[Ventral impressions of the hypopharynx. A differential diagnostic problem]. / Ventrale Impressionen des Hypopharynx. Ein differentialdiagnostisches Problem.

Two impressions can be seen on the ventral aspect of the hypopharynx and upper oesophagus; on static images it is difficult to differentiate these from small tumours. In order to evaluate this region more accurately, we have examined 150 patients by means of rapid rate cinematography. In 52.6% we found a constant irregular or convex impression formed by the cricoid; in the other cases this was not seen or was quite minimal. In 93% a sub-cricoid impression could be demonstrated which was due to lax mucosa. Characteristically, this showed a variable appearance during the passage of a bolus. Only the cricoid impression was associated with dysphagia.

[Imaging of epiphyseolysis of the femur head in the magnetic resonance tomogram]. / Die Darstellung der Epiphyseolysis capitis femoris (ECF) im Magnetresonanztomogramm (MRT).

The diagnosis of epiphyseolysis of the femoral head in its early stages is often unclear when using conventional radiography. In order to obtain additional information, we examined seven patients by means of MRT. In all cases the T1-weighted sequences showed widened, ill-defined epiphyseal plates. The epiphyseal displacement was shown accurately by sections of the sagittal plane. T2-weighted sequences showed the presence of an effusion in the hip joints of five patients. In all patients there was increased signal intensity in the metaphysis and in the femoral neck and head. The increased signal intensity appears to be an early sign for the presence of an epiphyseolysis.