Assessing the effect of CT slice interval on unidimensional, bidimensional and volumetric measurements of solid tumours.

OBJECTIVES: To study the magnitude of differences in tumour unidimensional (1D), bidimensional (2D) and volumetric (VOL) measurements determined from computed tomography (CT) images reconstructed at 5, 2.5 and 1.25 mm slice intervals. MATERIALS AND METHODS: A total of 118 lesions in lung, liver and lymph nodes were selected from 30 patients enrolled in early phase clinical trials. Each CT scan was reconstructed at 5, 2.5 and 1.25 mm slice intervals during the image acquisition. Lesions were semi-automatically segmented on each interval image series and supervised by a radiologist. 1D, 2D and VOL were computed based on the final segmentation results. Average measurement differences across different slice intervals were obtained using linear mixed-effects analysis of variance models. RESULTS: Lesion diameters ranged from 6.1 to 80.1 mm (median 18.4 mm). The largest difference was seen between 1.25 and 5 mm (mean difference of 7.6% for 1D [P < 0.0001], 13.1% for 2D [P < 0.0001], -5.7% for VOL [P = 0.0001]). Mean differences between 1.25 and 2.5 mm were all within ±3.5% (within ±6% confidence interval). For VOL, there was a larger average difference between measurements on different slice intervals for the smaller lesions (<10 mm) compared with the larger lesions. CONCLUSIONS: Different slice intervals may give different 1D, 2D and VOL measurements. In clinical practice, it would be prudent to use the same slice interval for consecutive measurements.

[Renal cell carcinoma- diagnosis by computed tomography]. / Rolul tomografiei computerizate în diagnosticul cancerului renal chistic.

In approximately 10% of cases, renal cell carcinoma (RCC) could present as a fluid- filled cystic mass. There are three mechanisms by which RCC may become cystic: extensive cystic necrosis, intrinsic cystic growth and origin from the epithelium lining a simple renal cyst. Simple renal cysts are very common. Uncommonly these cysts are complicated by hemorrhage, infection and possibly ischemia. The goal of the radiologist in evaluating these cystic lesions is to distinguish malignant neoplastic cystic masses from non-neoplastic complicated cysts so that appropriate management can be undertaken: RCC is best treated by surgical excision while non-neoplastic complicated cysts do not require surgery. The radiologic findings in these cystic masses which must be carefully evaluated include calcification, abnormal density, septations, nodularity, wall thickening and enhancement.

[Role of computerized tomography in the diagnosis of transitional cell carcinoma of the upper urinary tract]. / Rolul tomografiei computerizate în diagnosticul carcinomului tranzitional de uroteliu superior.

PURPOSE: To evaluate the computed tomography (CT) semiological criteria used in the diagnosis of transitional cell carcinoma of the upper urinary tract. MATERIALS AND METHODS: 26 patients with transitional cell carcinoma of the upper urinary tract underwent preoperative CT. In all cases nephroureterectomy was performed and CT and histopathologic findings were compared. RESULTS: 16 tumors were infiltrative and 10 tumors were sessile. The smallest tumour had 7 mm diameter and the largest one 13 cm. Associated focal hydronephrosis appeared in 11 cases and diffuse hydronephrosis in 7 cases. The vast majority of these tumors (69.23%) had a 21 to 50 Hounsfield Units enhancement. CONCLUSIONS: CT is a powerful tool to diagnose transitional cell carcinoma of the upper urinary tract when data acquired in intravenous urography and echography are equivocal.