ABSTRACT
Background & objectives: With the ethical concern about the dose of CT scan and wide use of CT in protocol of suspected renal colic, more attention has been paid to low dose CT. The aim of the present study was to make a comparison of unenhanced low-dose spiral CT localization with unenhanced standard-dose spiral CT in patients with upper urinary tract calculi for minimally invasive percutaneous nephrolithotomy (MPCNL) treatment. Methods: Twenty eight patients with ureter and renal calculus, preparing to take MPCNL, underwent both abdominal low-dose CT (25 mAs) and standard-dose CT (100 mAs). Low-dose CT and standard-dose CT were independently evaluated for the characterization of renal/ureteral calculi, perirenal adjacent organs, blood vessels, indirect signs of renal or ureteral calculus (renal enlargement, pyeloureteral dilatation), and the indices of localization (percutaneous puncture angulation and depth) used in the MPCNL procedure. Results: In all 28 patients, low-dose CT was 100 per cent coincidence 100 per cent sensitive and 100 per cent specific for depicting the location of the renal and ureteral calculus, renal enlargement, pyeloureteral dilatation, adjacent organs, and the presumptive puncture point and a 96.3 per cent coincidence 96 per cent sensitivity and 93 per cent specificity for blood vessel signs within the renal sinus, and with an obvious lower radiation exposure for patients when compared to standard-dose CT (P<0.05). The indices of puncture depth, puncture angulation, and maximum calculus transverse diameter on the axial surface showed no significant difference between the two doses of CT scans, with a significant variation in calculus visualization slice numbers (P<0.05). Interpretation & conclusions: Our findings show that unenhanced low-dose CT achieves a sensitivity and accuracy similar to that of standard-dose CT in assessing the localization of renal ureteral calculus and adjacent organs conditions and identifying the maximum calculus transverse diameter on the axial surface, percutaneous puncture depth, and angulation in patients, with a significant lower radiation exposure, who are to be treated by MPCNL, and can be used as an alternative localization method.
ABSTRACT
BACKGROUND AND OBJECTIVES: The aim of this study is to compare polysomnography (PSG) data and upper airway morphology between a position-dependent sleep apnea (PDSA) group and a position-independent sleep apnea (PISA) group. MATERIALS AND METHODS: This is a retrospective analysis into which 58 patients who were evaluated with overnight polysomnography, lateral cephalometry, and multidetector computed tomography (MD-CT, spiral CT scan) to diagnosis obstructive sleep apnea were enrolled. The patients were divided in two groups: the PDSA group who had a supine apnea-hypopnea index (AHI) that was at least two times higher than the non-supine AHI and the PISA group in whom the AHI in the supine position was less than twice that in the lateral position. Twelve cephalometric variables were measured. MD-CT measurements were evaluated in four neck levels from the hard palate to the top of the epiglottis. Minimal cross-sectional area (mCSA) and collapsibility index (CI) were calculated at each level. RESULTS: AHI was significantly higher in the PISA compared with PDSA. None of the cephalomeric measurements were significantly different between the two groups. In the MD-CT measurements, the mCSA of the low retropalate area (LRP) in the awake state was significantly lower in the PISA group compared to that in the PDSA group. In the sleep state, the CI was significantly higher in the high and low retroglossal areas (HRG and LRG) in the PISA compared to those in the PDSA group. CONCLUSION: In the supine position, PISA had increased collapsibility at the levels of the HRG and LRG during sleep compared to those in PDSA. In the future, a further evaluation with MD-CT in a non-supine position is needed.
Subject(s)
Humans , Cephalometry , Epiglottis , Multidetector Computed Tomography , Neck , Palate, Hard , Polysomnography , Retrospective Studies , Sleep Apnea Syndromes , Sleep Apnea, Obstructive , Supine Position , Tomography, Spiral ComputedABSTRACT
Objective:To established a modified implanting model of VX2 liver tumor in rabbit on the base of the classic implanting method, and compared the results within the two methods. Methods:30 rabbits with the mean weight of (2.65?0.29)kg were divided randomly into two groups with 15 rabbits each. The rabbits in Group A received classic implantation for induction of the liver tumor model, and Group B were inducted by injecting a piece of tumor tissue into the left anterior lobes of liver. Implanting time of each group was recorded and compared, and spiral CT scan was performed at 8th day, 15th day, 22nd day, 29th day postoperatively. The manifestation of tumors in CT scan was observed and tumor volume was calculated simultaneously with formula V=1/2ab2 (a=the shortest diameter and b=the longest diameter).Each tumor was confirmed through pathology. Results:The implanting time of Group A and Group B were (9.47?2.85)min and (5.85?1.62)min, respectively, with significant difference between them. Besides, there was statistical difference of the achievement ratio between two groups, as it was 53.3% for Group A and 86.7% for Group B. No significant difference was found for the tumor growth between two groups. Conclusion:Modified implanting method for induction of the rabbit liver tumor model was superior to the classic implanting method.