Can the CT planning image determine whether a kidney stone is radiopaque on a plain KUB?

Perioperative Fast-Track Surgery Nursing Intervention for Patients with Kidney Stone Disease under Computed Tomography Imaging

This research aims to analyze the clinical intervention effect of perioperative fast-track surgery (FTS) nursing on patients with kidney stone disease (KSD) under computed tomography (CT) imaging. One-hundred KSD patients were selected as research objects and grouped after CT examination. These objects were randomly divided into a research group (FTS nursing intervention, n = 50) and a control group (general routine nursing intervention, n = 50). The preoperative psychological status of patients was compared between the two groups, using Self-rating Anxiety Scale and Self-rating Depression Scale. The hunger and thirst situations were compared using Numerical Rating Scale; postoperative recovery time, incidence of complications, and nursing satisfaction were also compared. The high-density shadow could be clearly observed in the right kidney of the patients in the CT imaging examination. The nursing outcomes suggested that there was no notable difference in hunger between the two groups, and anxiety, depression, and thirst in the research group were highly better than those in the control group (P < 0.01). The time of the first exhaust, the time of body temperature returning to normal, the time of getting out of bed, and the length of hospital stay in the research group were all shorter than those in the control group (P < 0.05). The total postoperative satisfaction of the research group (98.00%) was greatly better than the 88.00% in the control group (P < 0.05). As the FTS concept was applied in the perioperative nursing of KSD patients under CT imaging, the preoperative and postoperative negative emotions of patients could be improved. Thereby, the postoperative recovery rate of patients was promoted, postoperative complications and patients' pain were reduced, and the postoperative quality of life of patients was also improved.

Ray sum image: its efficacy in renal tract calculus detection

AIM

To determine the efficacy of a ray sum image derived from computed tomography of the kidneys, ureters and bladder (CT KUB) in detecting renal tract calculi and whether this can replace the baseline abdominal radiograph (AXR).

MATERIALS AND METHODS

This is a retrospective study performed at a tertiary referral centre examining adult patients referred for urolithiasis who had undergone AXR within 24 hours of the diagnostic CT KUB. AXR and ray sum image for calculus visibility were reviewed blindly by two readers. Anteroposterior thickness of the patient, presence of excess gas/faecal material, calculus size, location, and mean attenuation were analysed to determine effect on the AXR and ray sum sensitivity.

RESULTS

One hundred and fifty-two calculi were examined with ray sum image sensitivity of 44% (95% confidence interval [CI]: 36-52) and AXR 30% (95% CI: 22-38). Calculus size and mean attenuation significantly affected sensitivities of both ray sum and AXR. There was substantial agreement between the two techniques with κ(Kappa)=0.70 (95% CI: 0.58-0.81, p<0.001).

CONCLUSION

Ray sum image as a post-processed image derived from CT KUB dataset may be a viable alternative to the baseline AXR in patients with CT proven urolithiasis. This would reduce patient radiation dose and streamline workflow in busy radiology and emergency departments.

Alternatives to the baseline KUB for CTKUB-detected calculi: evaluation of CT scout and average and maximum intensity projection images

PURPOSE

A CT of the kidneys, ureters, and bladder (CTKUB) is the investigation of choice in suspected renal colic. Plain kidney, ureter, and bladder radiographs (KUB) can be used to monitor the progress of a stone if radiographically visible on a baseline KUB. This study aims to determine if a low-dose CT Scout, thick-slab average intensity projection (AIP), or maximum intensity projection (MIP) images are suitable as substitutes for a baseline KUB.

METHOD

A retrospective review of patients from a tertiary adult institute that had a positive CTKUB and a KUB within 4 h of the CT was performed. Two consultant radiologists independently reviewed the KUB, CT Scout, AIP, and MIP for stone visibility and their sensitivities and agreement values were compared. Stone characteristics (size, location, and peak Hounsfield units) and patient thickness were recorded and examined for any association with discordant results.

RESULTS

74 stones were evaluated for the study. KUB had a sensitivity of 66.2% (95% CI 54.3-76.8), CT Scout 47.3% (95% CI 35.6-59.3), AIP 55.4% (95% CI 43.4-67.0), and MIP 83.8% (95% CI 73.4-91.3). Fair agreement was found between the KUB and both CT Scout (κ=0.363, 95% CI 0.167-0.558) and AIP (κ=0.384, 95% CI 0.175-0.592). Moderate agreement was found between the KUB and MIP (κ=0.412, 95% CI 0.198-0.625). Neither any stone characteristic nor patient thickness had a significant association with discordant results.

CONCLUSION

None of the possible substitutes for a baseline KUB showed strong agreement with the KUB. Low-dose CT Scouts have a similar sensitivity to the published literature for higher dose CT Scouts.

Using a three-dimensional computer assisted stone volume estimates to evaluate extracorporeal shockwave lithotripsy treatment of kidney stones

This study describes and evaluates the use of non-contrast enhanced computerized tomography (NCCT) before and after extracorporeal shockwave lithotripsy (SWL). Computer measured stone volume was used as an exact measurement for treatment response. 81 patients received SWL of kidney stones at Herlev Hospital between April 2013 and January 2014 and follow-up was possible in 77 (95 %) patients. NCCT was used before and after treatment. Treatment response was expressed as a reduction of the stone volume. Stone characteristics as the stone volumes, HU, SSD and localization were measured by radiologist using a vendor non-specific computer program. Complications, patient characteristics and additional treatment were registered. On average, 5858 shocks were given each patient. The follow-up NCCT was performed 24 days after treatment. It was possible to calculate the stone volume in 88 % of the patients-the remaining 12 % it was not possible due to stone disintegration. The stone free rate was 22 %. The average relative reduction in stone burden was 62 %. Only 8 % of the patients were radiological non-responders. Steinstrasse was observed in 13 (17 %) and 28 (36 %) patients had additional treatment performed. Irradiation dose per NCCT was 2.6 mSv. Stone volume could be calculated in most patients. The relative reduction in stone burden after treatment was 62 %. The stone volume was redundant when evaluating stone free patients, but in cases of partial response it gave an exact quantification, to be used in the further management and follow-up of the patients.

Do we really need kidneys-ureters-bladder radiography to predict stone radiopacity before treatment with shockwave lithotripsy? Development and internal validation of a novel predictive model based on computed tomography parameters

PURPOSE

To produce and validate a predictive model based on CT parameters for calculating the probability of a stone to be visible on fluoroscopy of shockwave lithotripsy (SWL) and to compare its accuracy to that of kidneys-ureters-bladder (KUB) radiography.

METHODS

We retrospectively analyzed 306 patients (sample group) who underwent an SWL between March 2011 and August 2012. A multivariate analysis of several parameters extracted from the preoperative CT scan was conducted to identify independent predictors for radiopacity on SWL fluoroscopy. The results were used for the creation of a predictive model. Internal validation was made on a group of 75 patients (validation group) treated from September 2012 until December 2012. Predictive accuracy of the model was evaluated by receiver operating characteristic (ROC) curve and calibration plot. The ROC curve was also used for comparing the predictive accuracy of the model to that of KUB radiography.

RESULTS

From 306 evaluated stones, 238 (77.8%) were visible on fluoroscopy. Results of the multivariate analysis revealed that stone size (P<0.001), stone attenuation (P<0.001), location in the midureter (P<0.001), the distance between the stone and the anterior abdominal wall (P<0.001), and fat thickness of the anterior abdominal wall (P=0.001) were all independent predictors for stone radiopacity on fluoroscopy. A predictive model was produced based on the above parameters. The model demonstrated high calibration and areas under the curve of 0.923 and 0.965 in the sample and validation group, respectively, while its predictive performance was significantly higher (P<0.001) of that of KUB radiography (area under the curve=0.727).

CONCLUSIONS

This novel model can estimate with high accuracy stone radiopacity on SWL fluoroscopy using parameters of CT scan and thus it can be used as an alternative to KUB radiography for treatment planning.

CT-Based Determination of Ureteral Stone Volume: A Predictor of Spontaneous Passage

INTRODUCTION AND OBJECTIVES

Which ureteral stone can pass spontaneously? It is hard to answer this question exactly. The size and location of the stone are the most important predictors. However, there is still a considerable gray zone that needs to be clarified. We try to identify the role of stone volume (SV) in the prediction of spontaneous passage (SP).

MATERIALS AND METHODS

Seventy-eight patients with a solitary ureteral stone were retrospectively evaluated. Ureter SV measurements were taken in three planes and were calculated using the following formula: V = (X) × (Y) × (Z) × 0.52. SVs, and the longest diameters (LDs) were compared between patients who passed stones spontaneously and those who needed intervention.

RESULTS

The SVs and LDs were significantly lower in patients who passed stones spontaneously than in patients who required intervention (41.2 ± 35.5 vs 128.1 ± 91.1 mm(3), p = 0.001; 5.7 ± 1.8 vs 7.4 ± 1.7 mm, p = 0.001). The optimum cutoff values were 7.0 mm and 52.6 mm(3) for the LD and SV, respectively. For those stones of ≤7 mm, the volumes of the stones that could and could not pass did not differ significantly. However, the volume of the stones >7.0 mm that could pass was significantly higher than of those that could not. SP was 30.6% for stones >7 mm; however, when we removed the stones >52.6 mm(3), SP increased to 75% for stones higher than 7 mm (p = 0.001).

CONCLUSIONS

To classify ureteral stones using only one parameter such as stone diameter may lead to heterogeneity within the group. SV may be used in addition to size to determine a more definite homogeneous group to predict SP more precisely.