Higher Hounsfield Unit Values Research Articles

Stones hounsfield unit value and predictors of urinary leakage after PCNL

BackgroundTo evaluate the predictive factors of urinary leakage (UL) following percutaneous nephrolithotomy (PNL) and to investigate the relationship between Hounsfield unit (HU) of stone and UL.MethodsWe retrospectively reviewed the data of 728 patients who underwent PNL between January 2012 and January 2017. In total, 396 patients were eligible for the study. Patient demographics, renal factors, stone properties and operative details were collected. The association between UL and these variables were assessed by univariate and multivariate analysis.ResultsThere was no statistically significant correlation considering age, body mass index and the presence of hypertension. The presence of diabetes mellitus (DM) was significantly correlated with UL (p < 0.001). Kidney related factors such as parenchymal thickness, hydronephrosis grade (HN), previous stone treatment, and stone related factors, such as stone surface area, stone burden, stone localization and HU value of stone, were found to affect UL status significantly (p < 0.001). Operation time, fluoroscopy time, treatment outcome, j stent use, percutenous nephrostomy (PCN) catheter stay time and the hospitalization time also had significant effect on UL (p < 0.001). Multivariable logistic analysis showed that presence of DM, parenchymal thickness, HU values, HN, operation time, j stent use, and PCN catheter stay time are independently related with UL following PCNL. Moreover, we determined a HU cut-off value of 933 with ROC analysis, which demostrated 84.9% sensitivity and 67.1% specificity for predicting UL.ConclusionThis study has shown that we are more likely to encounter postoperative UL in stones with higher HU values. Therefore, we suggest clinicians to inform patients with this type of kidney stones about the probable complication of UL.

Computed tomography osteoabsorptiometry-based investigation on subchondral bone plate alterations in sacroiliac joint dysfunction

Sacroiliac joint dysfunction (SIJD) is an underappreciated source of back pain. Mineralization patterns of the sacroiliac (SIJ) subchondral bone plate (SCB) may reflect long-term adaptations to the loading of the joint. Mineralization densitograms of 27 SIJD patients and 39 controls, were obtained using CT osteoabsorptiometry. Hounsfield unit (HU) values of the SCB mineralization of superior, anterior and inferior regions on the iliac and sacral auricular surfaces were derived and statistically compared between SIJD-affected and control cohorts. Healthy controls showed higher HU values in the iliac; 868 ± 211 (superior), 825 ± 121 (anterior), 509 ± 114 (inferior), than in the sacral side; 541 ± 136 (superior), 618 ± 159 (anterior), 447 ± 91 (inferior), of all regions (p < 0.01). This was similar in SIJD; ilium 908 ± 170 (superior), 799 ± 166 (anterior), 560 ± 135 (inferior), sacrum 518 ± 150 (superior), 667 ± 151 (anterior), 524 ± 94 (inferior). In SIJD, no significant HU differences were found when comparing inferior sacral and iliac regions. Furthermore, HU values in the inferior sacral region were significantly higher when compared to the same region of the healthy controls (524 ± 94 vs. 447 ± 91, p < 0.01). Region mineralization correlated negatively with age (p < 0.01). SIJD-affected joints reflect a high mineralization of the sacral inferior region, suggesting increased SIJD-related mechanical stresses. Age-related SCB demineralization is present in all individuals, regardless of dysfunction.

Synthesis of colloidal silver, platinum, and mixture of silver-platinum nanoparticles using pulsed laser ablation as contrast agent in computed tomography

Introduction : Over the last seven years, the development of nanoparticles as computed tomography (CT) contrast agents has increased significantly. In this present work, syntheses of colloidal silver nanoparticles (Ag NPs), platinum nanoparticles (Pt NPs), and silver-platinum nanoparticles (Ag-Pt NPs) have been successfully performed using pulsed laser ablation method in deionized water media.Materials and Methods : Experimentally, an neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm, 45 mJ, 10 Hz) was focused on a high-purity metal plate including Ag and Pt plates, which are placed in deionized water medium. Colloidal Ag NPs has been succesfully produced with a dark brownish-yellow color with an averaged diameter of 24 nm. For colloidal Pt NPs, the liquid has transparent color with an averaged diameter of 20 nm. Both colloidal nanoparticles of Ag and Pt were then mixed to obtain a mixture composition of Ag and Pt with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, respectively, with a concentration of each of 10 part per million (ppm). The Ag NPs, Pt NPs, and Ag-Pt NPs mixture were then examined as contrast agents in computed tomography (CT) scan. The CT Scan was set at 80 kV and 100 mAs. Results: The imaging results of these agents were measured in Hounsfield Unit (HU), showing 13.5, 12.8, 13.3, 14.1, and 17.3 HUs for colloidal Ag NPs only, colloidal Ag and Pt NPs with ratios of Ag:Pt of 75:25%, 50:50%, 25:75%, and colloidal Pt NPs only, respectively.Conclusion: These findings confirmed that for colloidal solution containing high concentration of platinum (Pt NPs only and colloidal Ag and Pt NPs with ratio of 25:75%) has higher HU values compared to the case of Pt NPs. The higher HU value for platinium can be attributed to its higher density.

Three-dimensional distribution of CT attenuation in the lumbar spine pedicle wall

This study investigated in vivo the three-dimensional distribution of CT attenuation in the lumbar spine pedicle wall measured in Hounsfield Unit (HU). Seventy-five volunteers underwent clinical lumbar spine CT scans. Data was analyzed with custom-written software to determine the regional variation in pedicle wall attenuation values. A cylindrical coordinate system oriented along the pedicle’s long axis was used to calculate the pedicular wall attenuation distribution three-dimensionally and the highest attenuation value was identified. The pedicular cross-section was divided into four quadrants: lateral, medial, cranial, and caudal. The mean HU value for each quadrant was calculated for all lumbar spine levels (L1–5). The pedicle wall attenuation was analyzed by gender, age, spinal levels and anatomical quadrant. The mean HU values of the pedicle wall at L1 and L5 were significantly lower than the values between L2–4 in both genders and in both age groups. Furthermore, the medial quadrant showed higher HU values than the lateral quadrant at all levels and the caudal quadrant showed higher HU values at L1–3 and lower HU values at L4–5 than the cranial quadrant. These findings may explain why there is a higher incidence of pedicle screw breach in the pedicle lateral wall.

The correlation of CBCT analysis derived bone density parameters with primary implant stability - a clinical study

Background/Aim. There are numerous studies on the usefulness of computed tomography (CT) in the assessment of the bone volume and morphology and on the relationship between CT and primary implant stability. But there is the scarcity of data about the correlation between bone density and the value of primary implant stability. The aim of this study was to examine the correlation of cone beam CT (CBCT) analysis derived bone density with primary stability value. Methods. Clinical prospective experimental study was conducted on 38 healthy patients missing one tooth in the lateral region. It was planned to install Bredent Blue Sky Narrow self-taping dental implants with dimensions 3.5 ? 10 mm. During preoperative preparation, a CBCT scan was performed on Planmeca apparatus, followed by preimplantation measurements and planning in the CBCT apparatus software (Romexis). The mean value of the average bone density was automatically generated and expressed in Hounsfield units (HU). Upon implant placement, we performed measurements of the primary implant stability using Osstell apparatus. Results. Of the 38 patients included in the study, there were 68.4% male patients and 31.6% female patients. The arithmetic mean of the measured bone density of all subjects in the study amounted to 536.2 HU. The arithmetic mean of dental implant primary stability for all subjects in the study was 68.7 ISQ. There was a statistically significant strong positive connection between HU and ISQ (r = 0.744, p &lt; 0.001). Higher HU values were connected to higher ISQ values. In the multivariate linear regression model, statistically significant predictors of higher ISQ values: males (B = 4.669; p = 0.047) and higher HU values (B = 0.032; p &lt; 0.001). Conclusion. In our clinical study, there was a statistically significant strong positive correlation between the bone density expressed in HU units, measured in the software of the CBCT device and the primary stability of dental implants expressed in ISQ units.

Relationship of Lower-extremity Deep Venous Thrombosis Density at CT Venography to Acute Pulmonary Embolism and the Risk of Postthrombotic Syndrome.

Background Acute deep venous thrombi (DVT) have higher Hounsfield unit values than chronic (bland) thrombi at CT venography. Purpose To determine the relationship between DVT thrombus density found on CT venography images to the presence of acute pulmonary embolism (PE) and the future risk of postthrombotic syndrome (PTS) in patients with DVT. Materials and Methods In this retrospective study, patients were divided into two groups: PE with DVT group and DVT-only group. Wells scores were recorded. Thrombus density ratios were calculated (DVT thrombus Hounsfield units/surrounding vein Hounsfield units). The presence or absence of PTS was determined from the results of the Venous Insufficiency Epidemiologic and Economic Study on Quality of Life (VEINES-QOL) questionnaires given to the patients with DVT. Statistical analyses used receiver operating characteristic curves and Spearman correlation analyses. Results Eighty-six patients were included; the mean age was 60 years ± 17 (51 men; PE with DVT group, 54 patients [63%]; DVT-only group, 32 patients [37%]). The mean thrombus density ratio was significantly higher in the PE with DVT group than in the DVT-only group (53.6% ± 12.4 [standard deviation] vs 42.8% ± 11.9, respectively; P < .001). At multivariable analysis, Wells score greater than 4 (odds ratio, 12.0; 95% confidence interval [CI]: 3.0, 47; P < .001) and higher thrombus density ratio (odds ratio, 1.1; 95% CI: 1.0, 1.2; P = .001) were independent predictors of PE. The diagnostic performance for the thrombus density ratio (area under the receiver operating characteristic curve, 0.74; 95% CI: 0.63, 0.85; P < .001) may be more discriminative than that of the Wells score (area under the receiver operating characteristic curve, 0.70; 95% CI: 0.59, 0.81; P = .002) for the presence of PE. In subgroup analysis, the thrombus density ratio and VEINES-QOL score were correlated (r = 0.61; 95% CI: 0.30, 0.80; P < .001). Conclusion Deep venous thrombosis (DVT) density ratio at CT venography was associated with acute pulmonary embolism in patients with lower-extremity DVT. © RSNA, 2019 Online supplemental material is available for this article.

Effect of Porous Titanium Granules on Bone Regeneration and Primary Stability in Maxillary Sinus

The aim of this randomized controlled study was to comparatively analyze the new bone (NB), residual bone, and graft-bone association in bone biopsies retrieved from augmented maxillary sinus sites by histomorphometry and microcomputed tomography (MicroCT) in a split-mouth model to test the efficacy of porous titanium granules (PTG) in maxillary sinus augmentation. Fifteen patients were included in the study and each patient was treated with bilateral sinus augmentation procedure using xenograft (equine origine, granule size 1000-2000 μm) and xenograft (1 g) + PTG (granule size 700-1000 μm, pore size >50 μm) (1 g), respectively. After a mean of 8.4 months, 30 bone biopsies were retrieved from the implant sites for three-dimensional MicroCT and two-dimensional histomorphometric analyses. Bone volume and vital NB percentages were calculated. Immediate after core biopsy, implants having standard dimensions were placed and implant stability quotient values were recorded at baseline and 3 months follow-up. There were no significant differences between groups according to residual bone height, residual bone width, implant dimensions, and implant stability quotient values (baseline and 3 months). According to MicroCT and two-dimensional histomorphometric analyses, the volume of newly formed bone was 57.05% and 52.67%, and 56.5% and 55.08% for xenograft + PTG and xenograft groups, respectively. No statistically significant differences found between groups according to NB percentages and higher Hounsfield unit values were found for xenograft + PTG group. The findings of the current study supports that PTG, which is a porous, permanent nonresorbable bone substitute, may have a beneficial osteoconductive effect on mechanical strength of NB in augmented maxillary sinus.

Does the Hounsfield Unit Value Determined by Computed Tomography Predict the Outcome of Percutaneous Nephrolithotomy?

We aimed to evaluate whether the Hounsfield unit (HU) value predicts outcome in percutaneous nephrolithotomy (PCNL). One hundred and seventy-nine patients who had undergone PCNL in our clinics in the last 4 years were included. Demographic and clinical data of the patients and complications, if any, were recorded. The mean age of the patients was 45.3 ± 14.3 years (range 5-82 y), and 111 of them were males (62%). The mean stone size and HU values were found to be 693.1 ± 628.0 (95-4200) mm(2) and 706.3 ± 245.0 (214-1325), respectively. In logistic regression analysis, the size of the stone, the opacity of the stone, and the HU values were found to be independent predictors of the failure of the procedure (P<0.05). A cutoff value of 677.5 was used for the HU in the receiver operating characteristics analysis. Having a HU value under the cutoff value increased the likelihood of procedure failure by 2.65 times, whereas stones residing in the staghorn localization increased failure by 5.68. It was also observed that if the stone's size was 485 mm(2) or more, the chance of failure increased by 1.9, whereas when the stone was nonopaque, failure increased by 6.04 times (P<0.05). There was a positive correlation between hematocrit decrease and a decrease in HU values (P<0.05), but no correlation was observed between the HU values and duration of surgery or fluoroscopy (P>0.05). In addition to the size and location of the stones, the HU value determined in the unenhanced CT scan may be one of the parameters affecting PCNL outcomes. PCNL is a more efficient method in stones with higher HU values. Therefore, the HU values may be a useful tool for the selection of the treatment modality in patients with renal stones.

Implant stability and bone density: assessment of correlation in fresh cadavers using conventional and osteotome implant sockets

To compare the primary stability of implants placed in conventional and osteotome sites and to evaluate the level of correlation between cutting torque measurements, resonance frequency analysis (RFA), and bone density. Eight human femoral heads were scanned with computed tomography for bone density measurements as Hounsfield units (HU), and individualized computed tomography-based surgical stents were prepared for placement of implants. Five implant sockets were prepared in each collum (CoF), caput (CaF), and trochanter (Tr-MM) section of the femoral heads using the conventional drilling technique or by a combination of drilling and use of an osteotome. Cutting-torque values (CTV) of the implants were measured by a manual torque wrench, followed by determination of implant stability quotients (ISQ) by RFA. The CTVs of implants were similar in the conventional group, but different in the osteotome group (P<0.05). There was a general tendency toward achieving higher CTV and ISQ values in CoF than CaF and Tr-MM (P<0.05), and measurements in CaF and Tr-MM were comparable (P>0.05). The mean HU of sites were similar, although CoF had higher HU values (P>0.05). CTV of implants in CaF and Tr-MM and ISQ values in CoF in the conventional groups were higher than those in the osteotome groups (P<0.05). The correlation between CTV and HU in Tr-MM was significant in the osteotome group, although no other correlations between CTV, ISQ, and HU could be detected (P>0.025). Conventional placement led to higher implant stability than the drilling and osteotome technique used in the study. No correlation could be found between CTV, RFA, and bone density.

Abstract 6108: Cardiac 64-slice Multidetector Computerized Tomography in the Management of Prosthetic Heart Valve Obstruction

Differentiation of pannus (P) and thrombus (THR) in prosthetic heart valve obstruction (PHVO) is still a confusive state at the present cardiological practise. Transesophageal echocardiography (TEE) is not fully capable method in this condition. We considered that cardiac 64-slice multidetector computerized tomography (MDCT) may have a value in the management of PHVO. Thirtytwo of 37 pts (22 male, mean age 47±11 years, 17 with atrial fibrillation) with PHVO (35 mitral, 2 tricuspid) were detected with TEE and also with MDCT before and after thrombolytic therapy (TT). Five pts having monoleaflet valves were excluded due to excessive artifacts. Pre-TT MDCT revealed at least 1 culprit mass (CM) which was considered to be the cause of PHVO and the Hounsfield unit (HU) values of CM’s were measured. All pts underwent TT under the guidance of serial TEE. The study consisted of 2 groups up to response of CM’s to TT demonstrated by post-TT MDCT. Group I: Successfully lysed CM’s, Group II: Nonresponder CM’s. TEE disclosed THR in 26 pts, however the cause of PHVO in 6 pts remained undefined. Pre-TT MDCT disclosed 45 distinct CM’s on 32 valves. Post-TT MDCT disclosed the number of CM’s for groups I and II: 26 and 19, respectively. Significant difference between mean HU values of groups was found [87 (range 11–180), 331 (range 168–510), respectively, p&lt;0.001]. A cut-off value of HU&gt;200 predicted nonresponder CM’s (sensitivity 94%, specificity 96%, p&lt;0.001). CM’s of 6 pts with undefined TEE findings were all in group II and pure P was demonstrated surgically. In group I, 17 of 26 (%65) CM’s were completely and the remaining partially lysed which was confirmed by TEE. A cut-off value of HU&lt;100 predicted complete lysis (sensitivity 100%, specificity %95, p&lt;0.001). Subgroup analysis of CM’s with HU=100–200 revealed 10% completely and 80% partially lysis and 10% remained unresponded as confirmed by TEE. MDCT can be a useful technique for evaluation of PHVO caused by THR or P formation. Higher HU values denote P whereas the lower values THR. MDCT can also predict the response to TT. The higher the HU value the less the successful outcome. The CM’s with HU&gt;200 are almost always resistant to TT.