Hydronephrotic kidney: pediatric three-dimensional US for relative renal size assessment--initial experience

PURPOSE

To prospectively evaluate accuracy of three-dimensional (3D) ultrasonography (US) for assessment of relative renal size in infants and children with hydronephrosis.

MATERIALS AND METHODS

Informed consent was obtained from parents and also from children who were older than 8 years. Study was approved by ethics committee. Two-dimensional (2D) US, 3D US, and scintigraphy were performed in 40 patients with hydronephrosis (age range, neonate to 16 years; seven girls, 33 boys) without acute renal disease. Twenty patients also underwent magnetic resonance (MR) urography. US and MR urography were performed by one experienced pediatric radiologist; 3D US and MR urographic volume calculations were performed by specifically trained radiologists. Three-dimensional US was performed with integrated 3D volume probes or external system based on electromagnetic positioning devices. At 2D US, kidney volume was calculated with application of ellipsoid equation. At MR urography and 3D US, real renal parenchymal volume was calculated with subtraction of dilated collecting system. Split renal function was assessed with static renal scintigraphy. Three-dimensional US results were graded with respect to image quality and compared with results of 2D US, scintigraphy, and MR urography by using mean difference percentage and standard deviation of the difference. All investigations were performed with blinding. Inter- and intraobserver variability were calculated with coefficient of variation.

RESULTS

In 76 of 80 kidneys, 3D US image of diagnostic quality was obtained. Three-dimensional US volume measurements compared well with MR urographic measurements (mean difference, -2.5% +/- 7.8 [standard deviation] vs 25.8% +/- 32.2 for 2D US) and with scintigraphically assessed split renal function (mean difference, 1.2% +/- 9.2 vs 15.9% +/- 43.8 for 2D US). Intra- and interobserver variability were +/-6.4% and +/-9.9%, respectively.

CONCLUSION

Initial experience with renal 3D US indicates that it is an accurate method for assessment of renal parenchymal volume and relative renal size, provided there is no acute renal disease.

Aortoiliac enhancement during computed tomography angiography with reduced contrast material dose and saline solution flush: influence on magnitude and uniformity of the contrast column

RATIONALE AND OBJECTIVES

To compare the magnitude and uniformity of aortoiliac contrast enhancement obtained from uniphasic contrast material injections versus contrast material injections with reduced iodine dose followed by a saline flush in aortoiliac multislice CT angiography (CTA).

METHODS

Twenty-nine patients with abdominal aortic aneurysms underwent aortoiliac CTA using protocols A and B. With protocol A, 120 mL contrast material (300 mgI/mL), and with protocol B, 100 mL contrast material followed by a 40-mL saline solution flush were administered at a flow rate of 4 mL/s. Quantitative analysis was performed by calculating mean aortoiliac attenuation, mean plateau deviation, and mean difference between maximum and minimum attenuation value for both groups. Qualitative analysis was performed by visual assessment of vascular enhancement using 2-dimensional and 3-dimensional postprocessing techniques.

RESULTS

The mean aortoiliac attenuation with protocol A was 291 +/- 62 HU, and with protocol B it was 285 +/- 61 HU. The difference of 6 HU was not statistically significant (P = 0.27). Mean plateau deviation was significantly smaller using protocol A than protocol B (16 +/- 9 HU vs. 20 +/- 10 HU, P = 0.03). In addition, the mean difference between maximum and minimum attenuation value was significantly smaller with protocol A than with protocol B (59 +/- 29 HU vs. 72 +/- 32 HU, P = 0.01). Visual analysis showed no difference in contrast material magnitude and homogeneity between the protocols.

CONCLUSIONS

In aortoiliac CTA, a saline solution flush after contrast material bolus allows an iodine dose reduction of approximately 20 mL without impairing the magnitude of contrast enhancement but degrades the uniformity of the contrast column. However, the degradation does not affect visual analysis.

Abdominal multidetector row computed tomography: reduction of cost and contrast material dose using saline flush

OBJECTIVE

To evaluate the potential of a saline solution flush after the contrast material bolus in abdominal multidetector row CT (MDCT) in contrast material dose and cost reduction.

METHODS

Abdominal MDCT was performed in 78 patients who were assigned randomly to 2 groups receiving 120 mL nonionic contrast material (300 mgI/mL) alone or 100 mL of the same contrast material pushed with 40 mL of saline solution. Mean attenuation values for both groups were measured in the liver, the spleen, the pancreas, the portal vein, the inferior vena cava, and the abdominal aorta. Cost analyses were performed for both groups.

RESULTS

There was no significant difference in parenchymal and vascular enhancement between both groups. The difference of the enhancement was 2 HU for the liver (P = 0.11), 2 HU for the spleen (P = 0.44), 3 HU for the pancreas (P = 0.38), 9 HU for the portal vein (P = 0.11), 3 HU for the inferior vena cava (P = 0.55), and 10 HU for the aorta (P = 0.06). Taking the costs of contrast material, saline solution, and disposal material into account, 7.30 dollars was saved by the patient using a saline solution flush.

CONCLUSIONS

Using a saline flush after the contrast material bolus in abdominal MDCT allows an iodine dose reduction of approximately 6 g, or 17%, without impairing mean parenchymal and vascular enhancement and a cost reduction of 7.30 dollars per patient.

Improvement of parenchymal and vascular enhancement using saline flush and power injection for multiple-detector-row abdominal CT

The aim of this study was to determine if a saline solution flush following low dose contrast material bolus improves parenchymal and vascular enhancement during abdominal multiple detector-row computed tomography (MDCT). Forty-one patients (24 men and 17 women; mean age 49 years, age range 27-86 years) underwent abdominal MDCT (collimation 4x5 mm, 15-mm table increment, reconstruction interval 5 mm, gantry rotation period 0.8 s) with a single- as well as with a double syringe power injector. Indication for examination were benign and malignant tumors and inflammatory diseases. Patients received 100 ml nonionic contrast material (300 mgI/ml) alone or pushed with 20 ml saline solution. Mean enhancement values for both protocols were measured in the liver, the spleen, the pancreas, the renal cortex, the portal vein, the inferior vena cava and the abdominal aorta. Double syringe power-injector protocol led to significantly higher parenchymal and vascular enhancement than single syringe power-injector protocol (p<0.05). The improvement in mean enhancement of the liver was 9 +/- 9 HU, of the spleen 8 +/- 10 HU, of the pancreas 7 +/- 9 HU, and of the renal cortex 8 +/- 20 HU. The improvement in mean enhancement of the portal vein was 10 +/- 17 HU of the inferior vena cava 8 +/- 13 HU and of the abdominal aorta 10 +/- 17 HU. The use of a double syringe power injector with saline flush following contrast material bolus significantly improves parenchymal and vascular enhancement during contrast-enhanced abdominal MDCT with low iodine doses.

Search for occult secondary osteoporosis: impact of identified possible risk factors on bone mineral density

OBJECTIVES

To determine whether the use of more elaborate diagnostic tests can identify possible risk factors for secondary osteoporosis and to evaluate the impact of these possible risk factors on the severity of bone disease in the study population.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

We have investigated 377 subjects (285 females, 92 males) with osteoporosis (T-score less than -2.5 in dual energy X-ray absorption) or nontraumatic lumbar vertebral fractures; these patients were referred to our hospital, a secondary care centre, for evaluation and treatment of osteoporosis.

RESULTS

Osteoporosis without attributable risk factor was diagnosed in 106 women (37%) and 30 men (33%). In 241 patients (179 women, 62 men) one or more possible risk factors for osteoporosis (in this paper also called subclinical disease) were revealed. The most common were lactose malabsorption, disturbed exocrine pancreatic function and renal tubular disturbances, including renal hypercalciuria, incomplete renal tubular acidosis and mild phosphate diabetes. The number of possible risk factors in the individual patient was significantly related to the severity of osteoporosis as assessed by Z-scores (Spearman correlation r = -0.43, P < 0.001, n = 172 for females; r = -0.28, P < 0.05, n = 65 for males).

CONCLUSIONS

All the identified subclinical diseases would have remained undetected if the currently accepted guidelines for the investigation of patients with osteoporosis were applied. The statistically significant correlation between the number of identified possible risk factors and the severity of bone disease in the individual patient strongly suggests the pathogenetic significance of the identified subclinical diseases. It is yet to be shown, whether specific treatment of these subclinical diseases yields additional improvement of bone mass as compared with standard treatment of osteoporosis.