Value of multislice helical CT scans and maximum-intensity-projection images to improve detection of ureteral stones at abdominal radiography.

OBJECTIVE: The purpose of this study was to assess the improvement in the detection of ureteral stones on abdominal radiographs when the stones were viewed on multislice helical CT scans and maximum-intensity-projection (MIP) images. SUBJECTS AND METHODS: The study included 72 patients with renal colic who underwent abdominal radiography and multislice helical CT. For each patient, a frontal MIP image was generated, and the stone, when present, was marked with a cross on the transverse CT scan. The cross appeared automatically on the corresponding MIP image. The CT examination was used as the standard of reference. The presence and location of ureteral stones on the abdominal radiographs were assessed during three interpretation sessions. In the first session, the abdominal radiographs were viewed alone. In the second, they were viewed with the transverse CT scans. In the third, the abdominal radiographs were viewed with the CT scans and the MIP images. RESULTS: Ureteral stones were present in 58 patients. The percentage of stones detected on the abdominal radiographs was 45% when the radiographs were viewed alone, 66% when they were viewed with the CT scans (p = 0.002 vs radiographs alone), and 78% when viewed with the CT scans and MIP images (p = 0.016 vs radiographs with CT scans). CONCLUSION: The sensitivity of stone detection on abdominal radiographs was greatest when the interpreters viewed the radiographs in conjunction with the CT scans and MIP images.

Lhermitte-Duclos disease. A case report.

We report one case of histologically proved Lhermitte-Duclos disease. Suspected on the basis of CT and angiography, the pre-operative diagnosis has been confirmed by the characteristic features of the lesion on MRI: a unilateral posterior fossa mass, hyperintense on proton density and T2-weighted images, hypointense on T1-weighted images, non enhancing after Gd administration. The gyral pattern was preserved, but a specific thickening of cerebellar folia was demonstrated. Despite a good post-operative short term prognosis, recurrence may occur. With a better depiction of lesion limits, MRI could improve the surgical approach and reduce the risk of subtotal excision.

Cervical myelopathy: MRI evaluation of cord compression.

In order to assess the consequences of cervical spinal cord compression in cervical myelopathy, MRI measurements of the sagittal diameter of the cervical spinal cord were obtained in 50 normal volunteers and 50 patients suffering from cervical myelopathy. Whatever the degree of stenosis, the values obtained in the latter group are significantly inferior to those of the normal control group (average mean diameter: normal group: 8.2 mm; cervical myelopathy: 6.2 mm).

MRI assessment of unsuspected dural sinus thrombosis.

In three patients with clinically unsuspected diagnosis, MRI has afforded a positive and conspicuous demonstration of dural sinus thrombosis, allowing specific treatment and followed by improvement in the patients' condition. Even in retrospect, CT examinations were nondiagnostic. Presenting symptoms were usual and nonspecific. CT and radionuclide scanning have proved valuable when performed on a clinically oriented basis. Angiography cannot be carried out without clear indications. MRI offers advantages in being a non-invasive technique without ionising radiation, allowing direct visualization and accurate delineation of the thrombus. MRI is definitely the method of choice to assess clinically suspected cerebral venous occlusion. As MRI diagnosis relies on a routine examination protocol, we believe that it will detect other unsuspected cases of dural sinus thrombosis.