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- Dahlman, Pär, et al.
(author)
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CT of the kidneys : what size are renal cell carcinomas when they cause symptoms or signs?
- 2007
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In: Scandinavian Journal of Urology and Nephrology. - : Informa UK Limited. - 0036-5599 .- 1651-2065. ; 41:6, s. 490-495
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Journal article (peer-reviewed)abstract
- Objective. To investigate the size of renal cell carcinomas (RCCs) when they cause macroscopic hematuria or other symptoms and/or signs. Material and methods. A retrospective review of 232 patients (136 males, 96 females; mean age 68±11 years; age range 40–90 years) with a diagnosis of RCC was undertaken. Patients were grouped according to the presenting symptoms and/or signs caused by the RCCs. Tumor size was measured on CT images. Results. Of the RCCs, 29% were found incidentally and 71% caused symptoms and/or signs. The incidentally found RCCs measured 4.9±2.6 cm (range 2–12 cm) and RCCs causing symptoms and signs measured 8.9±3.2 cm (range 3–18 cm); this size difference was significant (p<0.001). None of the RCCs causing macroscopic hematuria were <4 cm in size and only 3/165 (2%) of the symptomatic RCCs were <4 cm in size. Discussion. If small (<4 cm) RCCs do not cause symptoms, patients with them will not be referred for CT or any other imaging modality. Therefore, if a 2-cm RCC is found in a patient presenting with macroscopic hematuria, it is unlikely that this small RCC caused the hematuria and another cause of the hematuria must be ruled out.
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| 2. |
- Dahlman, Pär, et al.
(author)
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Optimization of computed tomography urography protocol, 1997 to 2008 : effects on radiation dose
- 2009
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In: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 50:4, s. 446-454
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Journal article (peer-reviewed)abstract
- BACKGROUND: Since computed tomography (CT) urography began to replace excretory urography as the primary imaging technique in uroradiology, the collective radiation dose to the patients has increased. PURPOSE: To examine the changes in the CT urography protocol for investigating suspected urinary tract malignancy between the years 1997 and 2008, and how these changes have influenced the mean effective dose. MATERIAL AND METHODS: The study was based on 102 patients (mean age 66.1+/-14.8 years, range 31-89 years; 30 female, 72 male) divided into five groups (groups A-E) corresponding to the time points at which changes were made to the CT urography protocol. The mean effective doses were estimated using the ImPACT CT Patient Dosimetry Calculator. RESULTS: The number of scan phases at CT urography was reduced from four to three in 1999, resulting in a reduction of the mean effective dose from 29.9/22.5 (female [F]/male [M]) mSv (group A) to 26.1/18.9 (F/M) mSv (group B). In 2001, mAs settings were adapted to patient size, and the mean effective dose was reduced to 16.8/12.0 (F/M) mSv (group C). In 2005, scans were performed with a multidetector-row CT equipped with automatic tube current modulation in the x- and y-axis (CARE Dose). The effective mAs was also lowered in the unenhanced and excretory phase, yet the mean effective dose increased to 18.2/13.1 (F/M) mSv (group D), since the effective mAs had to be increased in the corticomedullary phase to maintain image quality. In 2008, as tube current modulation in the x-, y-, and z-axis was introduced (CARE Dose4D), the mean effective dose was reduced to 11.7/8.8 (F/M) mSv (group E). CONCLUSION: This study shows that the individual mean effective dose to patients undergoing CT urography has decreased by 60%, from 29.9/22.5 (F/M) mSv in 1997 to 11.7/8.8 (F/M) mSv in 2008.
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