Interobserver variability and accuracy of computed tomographic assessment of nodal status in lung cancer.

To assess the interobserver variability of computed tomography in determining nodal status in non-small cell lung carcinoma, four experienced radiologists reviewed the computed tomographic scans of 147 patients. Interobserver variability was calculated using the kappa statistic. In addition, the accuracy of CT assessment of the nodal status by the four observers was measured by comparing their findings with thorough mediastinal exploration at both mediastinoscopy (n = 35) and thoracotomy (n = 112). Interobserver variability was large between the four radiologists regarding nodal status on a per-patient basis (kappa = 0.38). Sensitivity of computed tomography for the observers on a per-patient basis ranged from 40% to 69% with a 1.0-cm criterion and from 28% to 56% with a 1.5-cm criterion. From the large interobserver variability and the low sensitivities in this study it can be concluded that a negative result of computed tomography regarding mediastinal lymph nodes does not eliminate the need for mediastinoscopy or exploration of the mediastinum at the time of operation in patients with non-small cell lung cancer.

Computed tomography-guided scalp marking of cerebral surface lesions; an alternative to stereotaxis for small convexity lesions.

Marking of the skull prior to craniotomy on the basis of CT images can prove to be a difficult problem. The method reported here essentially consists of a procedure which involves tilting and manoeuvreing the head within the scanner so that the surface marker is perpendicular to the skull at the site of the lesion. This is easy, useful and not time consuming.

The "dural tail sign" in MRI of spinal meningiomas.

OBJECTIVE: Evaluation of "dural tail sign" in spinal meningiomas with gadolinium enhanced MRI in sagittal, axial, and especially coronal planes. MATERIALS AND METHODS: On a 0.5 T system, sagittal and axial T1 spin echo images (TR/TE 550/22) and sagittal T2 turbo spin echo images (TR/TE 2855/150) of the thoracolumbar spine were acquired. After administration of gadolinium (0.1 mmol/kg), sagittal, axial, and coronal T1 spin echo images (TR/TE 500/30) were acquired at the area of the tumors. RESULTS: The nonenhanced images demonstrated intradural and extramedullary tumors with a signal intensity in the T1 images a little higher than the adjacent spinal cord. After the administration of gadolinium, homogeneous enhancement of the tumors was seen. An even stronger enhancement was noticed at the borders of the tumors with the adjacent meninges, seen in the sagittal, axial, and even better in the coronal views. Both tumors proved histologically to be meningiomas. CONCLUSION: In evaluating spinal meningiomas, a gadolinium enhanced MRI of the spine in sagittal, axial, and especially coronal planes should be performed to detect "dural tails," very suggestive of meningioma. These three scanning planes are necessary to visualize the localization and extent of the tumors and their tails prior to surgery.

The best fit method. A simple way for measuring the volume of an intracerebral haematoma.

A method is described in which the volumes of intracerebral haematomas were measured by a method of best-fitting circles, in 23 consecutive patients. The results were compared with computer measurements of the haematoma volumes. The two measures corresponded well: mean difference 0.14 cc (-0.5%), range -4.5 to +6.5 cc (-17 to +26%).

Computed tomographic determination of coordinates for stereotaxis.

A visual, a computer-assisted and a trigonometric method for obtaining coordinates for stereotaxis are compared. Each method had its own deficiencies and produced comparable results.

Accuracy of computed tomography of the mediastinum in bronchogenic carcinoma.

The results of preoperative CT-scanning were compared with the pathological findings in lymph-nodes taken at mediastinoscopy and/or thoracotomy in 144 patients to determine the accuracy of CT of the mediastinum in staging lung cancer. Ninety-nine patients had squamous cell carcinoma, 31 adenocarcinoma, nine undifferentiated large-cell carcinoma and five patients had carcinoma of a mixed cellular type. Mediastinoscopy was done in 105 patients and thoracotomy in 126. The results of our study showed that CT is useful to select patients for mediastinoscopy for T1 lung cancer in general because of a negative predictive value of 98 per cent. CT is also useful for T2 and T3 lung cancer located at the left lower lobe or the right upper, middle or lower lobe (negative predictive value 87%). However, mediastinoscopy is always necessary in patients with T2 or T3 lung cancer at a main bronchus or a left upper lobe because of the low negative predictive value (58%). Preoperative aorto-pulmonary window evaluation is not recommended in case the CT-scan for the aortopulmonary window is negative because of a reasonable negative predictive value (81%).

Computed tomography in staging untreated patients with cervical cancer.

In a study to test the accuracy of computed tomography (CT) in staging untreated patients with cervical cancer, the interpretations of the CT scans of pelvis and abdomen of 56 consecutive patients were compared with surgical and/or clinical findings. This study clearly demonstrates that CT is unreliable in diagnosing parametrial tumour invasion and that it is not justified to make the therapeutically important differentiation between a IB or IIB stage with CT. In demonstrating metastatic lymph nodes, the accuracy of CT was only 75%, predominantly due to metastatic deposits in normal-sized nodes. CT was less accurate in diagnosing bladder wall and sigmoid invasion than cystoscopy and sigmoidoscopy, respectively, and was as accurate as urography in diagnosing ureteric obstruction. For these reasons, CT is not indicated as a routine procedure in cervical cancer staging, particularly not in the early stages of the disease. CT may be helpful in the higher clinical stages to measure tumour bulk and to get an impression about the whole extent of the disease.