MRI of atlanto-odontoid osteoarthritis.

We present the MRI appearances of advanced degenerative changes at the atlanto-odontoid (AO) joint. Changes including obliteration of the joint space, subchondral sclerosis and osteophytosis were clearly depicted on fast gradient-echo T1-weighted MRI images. Recognition of these changes may be helpful in the diagnosis in patients with suboccipital pain.

Pulmonary embolism: validation of spiral CT angiography in 149 patients.

PURPOSE: To assess the reliability of spiral computed tomographic (CT) angiography of the pulmonary arteries in the diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: One hundred forty-nine patients clinically suspected of having PE underwent spiral CT angiography and ventilation-perfusion (V-P) scintigraphy. Pulmonary angiography was also performed when the results of the V-P scan were indeterminate. Imaging results of spiral CT angiography were compared and validated against a normal perfusion scan in 40 patients, a high-probability scintigram in 53 patients, and a pulmonary angiogram in 56 patients. RESULTS: Spiral CT angiograms were of satisfactory diagnostic quality in all 149 patients. The sensitivity of spiral CT angiography for the detection of PE was 94% (64 of 68 patients) (observer 1) and 82% (56 of 68 patients) (observer 2), and the specificity was 96% (78 of 81 patients) (observer 2). Good interobserver agreement was obtained for spiral CT angiographic results (kappa = .774). Spiral CT angiography proved to be effective in the detection of PE in pulmonary arteries up to the segmental level but not in the smaller subsegmental branches. Isolated subsegmental PE accounted for three false-negative spiral CT angiographic results for both observers. CONCLUSION: Spiral CT angiography is an accurate method for the detection and exclusion of PE, with the exception of isolated subsegmental PE.

Role of spiral volumetric computed tomographic scanning in the assessment of patients with clinical suspicion of pulmonary embolism and an abnormal ventilation/perfusion lung scan.

BACKGROUND: A study was carried out to evaluate the potential place of spiral volumetric computed tomography (SVCT) in the diagnostic strategy for pulmonary embolism. METHODS: In a prospective study 249 patients with clinical suspicion of pulmonary embolism were evaluated with various imaging techniques. In all patients a ventilation/perfusion (V/Q) scan was performed. Seventy seven patients with an abnormal V/Q scan underwent SVCT. Pulmonary angiography was then performed in all 42 patients with a non-diagnostic V/Q scan and in three patients with a high probability V/Q scan without emboli on the SVCT scan. Patients with an abnormal perfusion scan also underwent ultrasonography of the legs for the detection of deep vein thrombosis. RESULTS: One hundred and seventy two patients (69%) had a normal V/Q scan. Forty two patients (17%) had a non-diagnostic V/Q scan, and in five of these patients pulmonary emboli were found both by SVCT and pulmonary angiography. In one patient, although SVCT showed no emboli, the angiogram was positive for pulmonary embolism. In one of the 42 patients the SVCT scan showed an embolus which was not confirmed by pulmonary angiography. The other 35 patients showed no sign of emboli. Thirty five patients (14%) had a high probability V/Q scan, and in 32 patients emboli were seen on SVCT images. Two patients had both a negative SVCT scan and a negative pulmonary angiogram. In one who had an inconclusive SVCT scan pulmonary angiography was positive. The sensitivity for pulmonary embolism was 95% and the specificity 97%; the positive and negative predicted values of SVCT were 97% and 97%, respectively. CONCLUSIONS: SVCT is a relatively noninvasive test for pulmonary embolism which is both sensitive and specific and which may serve as an alternative to ventilation scintigraphy and possibly to pulmonary angiography in the diagnostic strategy for pulmonary embolism.

Magnetic resonance imaging (MRI) in endometrial carcinoma; preoperative estimation of depth of myometrial invasion.

BACKGROUND: The incidence of pelvic and aortic lymph node involvement in endometrial carcinoma depends on both tumor differentiation grade and myometrial invasion depth. It was evaluated whether magnetic resonance imaging (MRI) provides a preoperative technique to assess the depth of myometrial invasion. METHODS: The study includes 34 patients with an endometrial carcinoma. MRI (T5 Gyroscan, Philips) was made a few days before operation. Myometrial invasion was divided in four categories. Cervical invasion was classified as absent, superficial or deep. For comparison an in vitro MRI of the uterus was made directly after the operation. Histo-pathological examination of the uterus was used as a golden standard of the depth of myometrial invasion. RESULTS: The estimation by MRI of the myometrial invasion depth was correct in 25 out of 31 patients. In three patients estimation was not possible, because of bad image quality. In four patients the MRI underestimated the cervical invasion. CONCLUSIONS: Preoperative MRI in patients with an endometrial carcinoma can be used to estimate myometrial and cervical invasion. Therefore, in combination with the histological grading of the tumor, a preoperative MRI can be used to select patients at high risk of nodal involvement.