Impact of urinary stone volume on computed tomography stone attenuations measured in Hounsfield units in a large group of Austrian patients with urolithiasis.

INTRODUCTION: To investigate retrospectively the impact of urinary stone volume on computed tomography stone attenuations measured in Hounsfield units in 253 patients with urolithiasis. MATERIAL AND METHODS: CT scans were performed in 253 patients with suspected urinary stone disease from 2008 to 2010 using CT-Scanner Siemens, SOMATOM, Sensation 64. One experienced radiologist (A.L) who was blinded to the chemical composition of the stones retrospectively reviewed images and analyzed data to determine the composition of the stones. The results were compared with the biochemical analysis results obtained by infrared spectroscopy (100 FTIR, PerkinElmer). RESULTS: 253 consecutive patients from 2008 to 2010 were included into analysis: 189 males, and 64 females. Mean age was 51.2. According to stone volume, stones were divided into 2 groups: 126 stones with volume of 4.3 mm or more, 127 stones with volume less than 4.3 mm. There was a significant relationship between stone volume and its CT attenuation only in stones with a volume 4.3 mm or more (p <0.05). CONCLUSIONS: We failed to show a significant relationship between stone volume and its attenuations in Hounsfield units. We could not distinguish uric acid stones from non uric acid stones.

Real-time sonoelastography of salivary glands for diagnosis and functional assessment of primary Sjögren's syndrome.

The purpose of this study was to investigate the value of real-time sonoelastography (RTS) of salivary glands for the diagnosis and assessment of glandular damage in primary Sjögren's syndrome (pSS). After institutional review board approval, 45 pSS patients, 24 sicca patients and 11 healthy controls were investigated prospectively. Questionnaires were completed and Saxon and Schirmer tests and routine blood tests carried out in all patients. All patients underwent B-mode ultrasonography and RTS of parotid and submandibular glands. Abnormal findings were graded from 0 to 48 and from 0 to 16, respectively. Sialoscintigraphy was done according to a routine protocol; scoring ranged from 0 to 12. Statistical analysis comprised receiver operating characteristic curve and multivariate regression analysis. Patients with pSS had higher B-mode (median score = 25 [range: 2-44] vs. 9 [1-20], p < 0.001) and RTS (6.5 [2-13] versus 4 [1-9], p < 0.001) scores than controls with sicca syndrome, yielding areas under the curve of 0.83 and 0.85 (p < 0.05 each), respectively for pSS diagnosis. In cases with an inconclusive B-mode ultrasonography result, RTS (cutoff score: ≥ 6) led to a sensitive (66.7%) and specific (85.7%) classification of patients and sicca controls. In multivariate regression analysis, RTS (regression coefficient = -0.48, p = 0.005), but not B-mode ultrasonography, reflected impaired salivary gland function according to the Saxon test, whereas none of the subjective measures of dryness or discomfort were related to ultrasonography results. B-mode and RTS results were both associated with sialoscintigraphy scores (regression coefficient = 0.66, p < 0.001, and regression coefficient = 0.55, p = 0.001, respectively). Reproducibility of B-mode ultrasonography and RTS was good, with intra-class correlation coefficients of 0.93 (95% confidence interval: 0.57-0.98) and 0.93 (95% confidence interval: 0.79-0.98), respectively. In summary, RTS might be a useful adjunct to B-mode ultrasonography for diagnosis and assessment of salivary gland impairment in primary Sjögren's syndrome.

The impact of iterative reconstruction on image quality and radiation dose in thoracic and abdominal CT.

PURPOSE: To compare the image quality and radiation dose between iterative reconstruction (IR) and standard filtered back projection (FBP) in CT of the chest and abdomen. MATERIALS AND METHODS: Thoracic CT was performed in 50 patients (38 male, 12 female; mean age, 51 ± 23 yrs; range, 7-85 yrs) and abdominal CT was performed in 50 patients (36 male, 14 female; mean age, 62 ± 13 yrs; range, 20-85 yrs), using IR as well as FBP for image reconstruction. Image noise was quantitatively assessed measuring standard deviation of Hounsfield Units (HU) in defined regions of interest in subcutaneous tissue. Scan length and Computed Tomography Dose Index (CTDI) were documented. Scan length, image noise, and CTDI of both reconstruction techniques were compared by using paired tests according to the nature of variables (McNemar test or Student t test). Overall subjective image quality and subjective image noise were compared. RESULTS: There was no significant difference between the protocols in terms of mean scan length (p>0.05). Image noise was statistically significantly higher with IR, although the difference was clinically insignificant (13.3 ± 3.0 HU and 13.6 ± 3.0 HU for thoracic CT and 11.5 ± 3.1 HU and 11.7 ± 3.0 HU for abdominal CT, p<0.05). There was no significant difference in overall subjective image quality and subjective image noise. The radiation dose was significantly lower with IR. Volume-weighted CTDI decreased by 64% (6.2 ± 2.5 mGy versus 17.1 ± 9.5 mGy, p<0.001) for thoracic CT and by 58% (7.8 ± 4.6 mGy versus 18.5 ± 8.6 mGy, p<0.001) for abdominal CT. CONCLUSIONS: Our study shows that in thoracic and abdominal CT with IR, there is no clinically significant impact on image quality, yet a significant radiation dose reduction compared to FBP.

Gd-EOB-DTPA enhanced MRI of the liver: correlation of relative hepatic enhancement, relative renal enhancement, and liver to kidneys enhancement ratio with serum hepatic enzyme levels and eGFR.

OBJECTIVES: To assess the correlation of relative hepatic enhancement (RHE), relative renal enhancement (RRE) and liver to kidneys enhancement ratio (LKR) with serum hepatic enzyme levels and eGFR in Gd-EOB-DTPA enhanced MRI of the liver and to assess threshold levels for predicting enhancement of the liver parenchyma. METHODS: Data of 75 patients who underwent Gd-EOB-DTPA enhanced MRI of the liver were collected. Images were obtained before contrast injection, during the early arterial phase, late arterial phase, venous phase, delayed phase, and hepatobiliary phase which was 20 min after Gd-EOB-DTPA administration. Signal intensity of the liver and the kidneys in all phases was defined using region-of-interest measurements for relative enhancement calculation. Serum hepatic enzyme levels and eGFR were available in all patients. Spearman correlation test was used to test the correlation of RHE, RRE and LKR with serum hepatic enzyme levels and eGFR. RESULTS: In the hepatobiliary phase all serum hepatic enzymes were significantly correlated with RHE; total bilirubin (TBIL) and cholin esterase (CHE) showed strongest correlations. TBIL and CHE were significantly correlated with RRE in the arterial phases. TBIL and CHE were significantly correlated with LKR in the arterial phase and hepatobiliary phase. eGFR showed no correlation. CONCLUSIONS: In Gd-EOB-DTPA enhanced MRI, TBIL and CHE levels may predict RHE, RRE and LKR.