Estimation of Pulmonary Motion in Healthy Subjects and Patients with Intrathoracic Tumors Using 3D-Dynamic MRI: Initial Results

Objective

To estimate a new technique for quantifying regional lung motion using 3D-MRI in healthy volunteers and to apply the technique in patients with intra- or extrapulmonary tumors.

Materials and Methods

Intraparenchymal lung motion during a whole breathing cycle was quantified in 30 healthy volunteers using 3D-dynamic MRI (FLASH [fast low angle shot] 3D, TRICKS [time-resolved interpolated contrast kinetics]). Qualitative and quantitative vector color maps and cumulative histograms were performed using an introduced semiautomatic algorithm. An analysis of lung motion was performed and correlated with an established 2D-MRI technique for verification. As a proof of concept, the technique was applied in five patients with non-small cell lung cancer (NSCLC) and 5 patients with malignant pleural mesothelioma (MPM).

Results

The correlation between intraparenchymal lung motion of the basal lung parts and the 2D-MRI technique was significant (r = 0.89, p < 0.05). Also, the vector color maps quantitatively illustrated regional lung motion in all healthy volunteers. No differences were observed between both hemithoraces, which was verified by cumulative histograms. The patients with NSCLC showed a local lack of lung motion in the area of the tumor. In the patients with MPM, there was global diminished motion of the tumor bearing hemithorax, which improved siginificantly after chemotherapy (CHT) (assessed by the 2D- and 3D-techniques) (p < 0.01). Using global spirometry, an improvement could also be shown (vital capacity 2.9 ± 0.5 versus 3.4 L ± 0.6, FEV1 0.9 ± 0.2 versus 1.4 ± 0.2 L) after CHT, but this improvement was not significant.

Conclusion

A 3D-dynamic MRI is able to quantify intraparenchymal lung motion. Local and global parenchymal pathologies can be precisely located and might be a new tool used to quantify even slight changes in lung motion (e.g. in therapy monitoring, follow-up studies or even benign lung diseases).     

Prospective Analysis on the Relation between Pain and Prostate Volume during Transrectal Prostate Biopsy

Objective

We wanted to assess the relationship between pain and the prostate volume during transrectal ultrasound (TRUS) guided biopsy.

Materials and Methods

Between July and September 2006, 71 patients scheduled for TRUS biopsy of the prostate were considered for inclusion to this study. These patients underwent periprostatic neurovascular bundle block with lidocaine prior to biopsy. Pain was assessed using a Visual Analogue Scale (VAS) during periprostatic neurovascular bundle block (VAS 1), during biopsy (VAS 2), and 20 minutes after biopsy (VAS 3). The mean pain scores were analyzed in the large prostate group (prostate volume > 40 cc) and the small prostate group (prostate volume ≤ 40 cc). P values < 0.05 were considered significant.

Results

The mean prostate volume was 42.2 cc (standard deviation: 8.6). The mean pain scores of VAS 1, 2 and 3 were 4.70 ± 1.61, 3.15 ± 2.44 and 1.05 ± 1.51, respectively. In the large prostate group, the mean pains scores of VAS 1, 2 and 3 were 4.75 ± 1.76, 3.51 ± 2.76 and 1.29 ± 1.70, respectively, whereas in the small prostate group, the means pain scores were 4.66 ± 1.46, 2.77 ± 2.0, and 0.80 ± 1.26, respectively. Although there were no statistical differences of VAS 1, the larger prostate group revealed higher pain scores of VAS 2 and 3 compared with the small prostate group (p < 0.05).

Conclusion

Patients with larger prostate volumes tend to feel more pain during and after TRUS guided prostate biopsy. Our findings suggest that additional analgesic strategies may be necessary when the patients with larger prostate undergo TRUS guided prostate biopsy.     

Perfusion MR Imaging in Gliomas: Comparison with Histologic Tumor Grade

Objective

To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas.

Materials and Methods

In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enhanced T2*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were calculated and compared between glioblastomas, anaplastic gliomas and low-grade gliomas.

Results

Mean rCBV ratios were 4.90°±1.01 for glioblastomas, 3.97°±0.56 for anaplastic gliomas and 1.75°±1.51 for low-grade gliomas, and were thus significantly different; p < .05 between glioblastomas and anaplastic gliomas, p < .05 between anaplastic gliomas and low-grade gliomas, p < .01 between glioblastomas and low-grade gliomas. The rCBV ratio cutoff value which permitted discrimination between high-grade (glioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and the sensitivity and specificity of this value were 100% and 75%, respectively.

Conclusion

Perfusion MR imaging is a useful and reliable technique for estimating the histologic grade of gliomas.     

Transient Ischemic Attack and Stroke Can Be Differentiated by Analyzing the Diffusion Tensor Imaging

Objective

We wanted to differentiate between transient ischemic attack (TIA) and minor stroke using fractional anisotropy and three-dimensional (3D) fiber tractography.

Materials and Methods

The clinical data, conventional magnetic resonance imaging (MRI), diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) were obtained for 45 TIA patients and 33 minor stroke patients. The fractional anisotrophy ratio (rFA) between the lesion and the mirrored corresponding contralateral normal tissue was calculated and analyzed. The spatial relationship between the lesion and the corticospinal tract (CST) was analyzed and the lesion sizes in the minor stroke patients and TIA patients were compared.

Results

Twenty-two of the 45 TIA patients (49%) revealed focal abnormalities following DWI. The rFA was significantly lower (p < 0.05) in the stroke patients (0.71 ± 0.29) compared to that of the TIA patients (1.05 ± 0.37). The CST was involved in almost all stroke lesions, but it was not involved in 68% of the TIA lesions. The TIA patients had significantly lower CST injury scores (3.25 ± 1.75) than did the stroke patients (8.80 ± 2.39) (p = 0.004).

Conclusion

Our data indicate that TIA and minor stroke can be identified by analyzing the rFA and the degree of CST involvement, and this may also allow more accurate prediction of a patient''s long-term recovery or disability.     

The Role of 18 F-FDG PET/CT in Assessing Therapy Response in Cervix Cancer after Concurrent Chemoradiation Therapy

Purpose

To determine whether persisting cervical fluorodeoxyglucose (FDG) uptake after concurrent chemoradiotherapy (CCRT) for cervical cancer can reflect residual malignancy.

Methods

F-FDG PET/CT was performed before and after CCRT in 136 patients with cervical cancer. The maximum and mean standardized uptake values (SUVmax and SUVmean) were recorded from PET/CT scans performed pre- and post-treatment. SUVs were correlated with treatment response after CCRT. Final treatment response was determined by MRI and further follow-up PET/CT. One hundred four of 136 patients underwent pelvic MRI, and 32 of 136 patients underwent further follow-up PET/CT. Patients were classified into two categories: patients with residual tumor or patients without residual tumor (complete responder). Pre- and post-treatment serum squamous cell carcinoma antigen (SCC) levels were also recorded for comparison. The optimal cutoff value of SUVmax for predicting residual cervical tumor was determined using receiver-operating characteristic (ROC) analysis.

Results

Of 136 patients, 124 showed complete response on further follow-up studies and 12 were confirmed to have residual tumor. The post-treatment SUVmax and pre-/post-treatment SUVmean of complete responders were significantly lower than those of patients with residual tumor: 2.5 ± 0.8 and 7.2 ± 4.2/1.9 ± 0.7 for complete responders and 5.7 ± 2.6 and 12.8 ± 6.9/3.7 ± 0.7 for patients with residual tumor (p < 0.05). The pre-treatment SUVmax and pre-/post-treatment serum SCC levels of the complete responders tended to be lower than those of patients with residual tumor, but this did not have statistical significance. Using ROC analysis, an optimal cutoff SUVmax of 4.0 on the post-treatment PET/CT yielded a sensitivity, specificity, positive predictive value, and negative predictive value of 92 %, 94 %, 61 %, and 99 %, respectively (p < 0.001).

Conclusions

Persistent cervical FDG uptake in¹⁸F-FDG PET/CT after CCRT for cervical cancer may be caused by residual tumor or post-therapy inflammation. A higher cutoff SUVmax than conventional criteria for cervical cancer in post-CCRT PET/CT might help to detect residual tumor.     

No holds barred sport fighting: a 10 year review of mixed martial arts competition

Objective

To identify the most salient medical issues that may be associated with mixed martial arts competition by determining the types and proportions of match stoppages.

Methods

Publicly available video footage of 1284 men competing in 642 consecutive televised matches from November 1993 to November 2003 was reviewed to determine the reasons for which matches were stopped. Matches were sanctioned by either a United States or Japan based mixed martial arts organisation.

Results

Of the 642 matches, 182 (28.3±3.4%) were stopped because of head impact, 106 (16.5±2.9%) because of musculoskeletal stress, 91 (14.1±2.7%) because of neck choke, 83 (12.9±2.6%) because of miscellaneous trauma, 173 (27.0±3.4%) because of expiration of match time, and seven (1.0±0.8%) because of disqualification, where the values in parentheses are percentages±95% confidence interval.

Conclusions

Blunt force to the head resulted in the highest proportion of match stoppages. Further research is warranted to delineate the morbidity associated with participation in mixed martial arts.     

Spectral CT: Preliminary Studies in the Liver Cirrhosis

Objective

To investigate the value of spectral CT imaging in the diagnosis and classification of liver cirrhosis during the arterial phase (AP) and portal venous phase (PVP).

Materials and Methods

Thirty-eight patients with liver cirrhosis (Child-Pugh class A/B/C: n = 10/14/14), and 43 patients with healthy livers, participated in this study. The researchers used abdominal spectral CT imaging during AP and PVP. Iodine concentration, derived from the iodine-based material-decomposition image and the iodine concentration ratio (IC_ratio) between AP and PVP, were obtained. Statistical analyses {two-sample t test, One-factor analysis of variance, and area under the receiver operating characteristic curve (A [z])} were performed.

Results

The mean normalized iodine concentration (NIC) (0.5 ± 0.12) during PVP in the control group was significantly higher than that in the study group (0.4 ± 0.10 on average, 0.4 ± 0.08 for Class A, 0.4 ± 0.15 for Class B, and 0.4 ± 0.06 for Class C) (All p < 0.05). Within the cirrhotic liver group, the mean NIC for Class C during the AP (0.1 ± 0.05) was significantly higher than NICs for Classes A (0.1 ± 0.06) and B (0.1 ± 0.03) (Both p < 0.05). The IC_ratio in the study group (0.4 ± 0.15), especially for Class C (0.5 ± 0.14), was higher than that in the control group (0.3 ± 0.15) (p < 0.05).The combination of NIC and IC_ratio showed high sensitivity and specificity for differentiating healthy liver from cirrhotic liver, especially in Class C cirrhotic liver.

Conclusion

Spectral CT Provides a quantitative method with which to analyze the cirrhotic liver, and shows the potential value in the classification of liver cirrhosis.     

Oral magnesium therapy, exercise heart rate, exercise tolerance, and myocardial function in coronary artery disease patients

Background

Previous studies have demonstrated that in patients with coronary artery disease (CAD) upward deflection of the heart rate (HR) performance curve can be observed and that this upward deflection and the degree of the deflection are correlated with a diminished stress dependent left ventricular function. Magnesium supplementation improves endothelial function, exercise tolerance, and exercise induced chest pain in patients with CAD.

Purpose

We studied the effects of oral magnesium therapy on exercise dependent HR as related to exercise tolerance and resting myocardial function in patients with CAD.

Methods

In a double blind controlled trial, 53 male patients with stable CAD were randomised to either oral magnesium 15 mmol twice daily (n = 28, age 61±9 years, height 171±7 cm, body weight 79±10 kg, previous myocardial infarction, n = 7) or placebo (n = 25, age 58±10 years, height 172±6 cm, body weight 79±10 kg, previous myocardial infarction, n = 6) for 6 months. Maximal oxygen uptake (VO_2max), the degree and direction of the deflection of the HR performance curve described as factor k<0 (upward deflection), and the left ventricular ejection fraction (LVEF) were the outcomes measured.

Results

Magnesium therapy for 6 months significantly increased intracellular magnesium levels (32.7±2.5 v 35.6±2.1 mEq/l, p<0.001) compared to placebo (33.1±3.1.9 v 33.8±2.0 mEq/l, NS), VO_2max (28.3±6.2 v 30.6±7.1 ml/kg/min, p<0.001; 29.3±5.4 v 29.6±5.2 ml/kg/min, NS), factor k (−0.298±0.242 v −0.208±0.260, p<0.05; −0.269±0.336 v −0.272±0.335, NS), and LVEF (58±11 v 67±10%, p<0.001; 55±11 v 54±12%, NS).

Conclusion

The present study supports the intake of oral magnesium and its favourable effects on exercise tolerance and left ventricular function during rest and exercise in stable CAD patients.     

Myocardial Blood Flow and Flow Reserve in Proximal and Mid-to-Distal Lesions of Left Anterior Descending Artery Measured By N-13 Ammonia PET/CT

Purpose

The purpose of this study is to compare the myocardial blood flow (MBF) and flow reserve (MFR) between proximal and mid-to-distal lesions of the left anterior descending artery (pLAD and mdLAD, respectively) using N-13 ammonia positron emission tomography/computed tomography (PET/CT).

Methods

Subjects were 11 patients (six men and five women, mean age 64.5 years) with known coronary artery disease (CAD) involving LAD studied by N-13 ammonia PET/CT. They were divided into two groups by the location of stenotic lesions, i.e. pLAD versus mdLAD. Global and regional MBF and MFR were measured and compared. Characteristics of perfusion defects including the number of involved segments, basal area involvement, location, size, and shape were also compared between the two groups.

Results

The regional MFR in mid-anterior segment was significantly lower in pLAD group (1.80 ± 0.35 vs 2.76 ± 1.13 for pLAD and mdLAD groups, respectively, p = 0.034), while global MFR was not different (2.10 ± 1.10 vs 2.34 ± 0.84). Both stress and rest MBF in LAD territories were not different in both groups. The size of the perfusion defects were significantly larger in pLAD group (44.0 ± 11.5 % vs 21.1 ± 15.8 %, p = 0.041). Other characteristics such as location, basal area involvement, and shape were not significantly different between two groups.

Conclusions

The proximal lesion makes lower MFR in the mid-anterior segment and larger perfusion defect in the LAD territory but comparable MBF compared with mdLAD lesion.

Electronic supplementary material

The online version of this article (doi:10.1007/s13139-013-0208-6) contains supplementary material, which is available to authorized users.     

Localized 1H-MR Spectroscopy in Moyamoya Disease before and after Revascularization Surgery

Objective

To evaluate, using localized proton magnetic resonance spectroscopy (¹H-MRS), the cerebral metabolic change apparent after revascularization surgery in patients with moyamoya disease.

Materials and Methods

Sixteen children with moyamoya disease and eight age-matched normal controls underwent MR imaging, MR angiography, conventional angiography, and ^99mTc-ECD SPECT. Frontal white matter and the basal ganglia of both hemispheres were subjected to localized ¹H-MRS, and after revascularization surgery, four patients underwent follow-up ¹H-MRS.

Results

Decreased NAA/Cr ratios (1.35±0.14 in patients vs. 1.55±0.24 in controls) and Cho/Cr ratios (0.96±0.13 in patients vs. 1.10±0.11 in controls) were observed in frontal white matter. After revascularization surgery, NAA/Cr and Cho/Cr ratios in this region increased. In the basal ganglia, there is no abnormal metabolic ratios.

Conclusion

Localized 1H-MRS revealed abnormal metabolic change in both hemispheres of children with moyamoya disease. Because of its non-invasive nature, ¹H-MRS is potentially useful for the preoperative evaluation of metabolic abnormalities and their postoperative monitoring.     

Evaluation of Tracheobronchial Diseases: Comparison of Different Imaging Techniques

Objective

To compare the clinical utility of the different imaging techniques used for the evaluation of tracheobronchial diseases.

Materials and Methods

Forty-one patients with tracheobronchial diseases [tuberculosis (n = 18), bronchogenic carcinoma (n = 10), congenital abnormality (n = 3), post-operative stenosis (n = 2), and others (n = 8)] underwent chest radiography and spiral CT. Two sets of scan data were obtained: one from routine thick-section axial images and the other from thin-section axial images. Multiplanar reconstruction (MPR) and shaded surface display (SSD) images were obtained from thin-section data. Applying a 5-point scale, two observers compared chest radiography, routine CT, thin-section spiral CT, MPR and SSD imaging with regard to the detection, localization, extent, and characterization of a lesion, information on its relationship with adjacent structures, and overall information.

Results

SSD images were the most informative with regard to the detection (3.95±0.31), localization (3.95±0.22) and extent of a lesion (3.85±0.42), and overall information (3.83±0.44), while thin-section spiral CT scans provided most information regarding its relationship with adjacent structures (3.56±0.50) and characterization of the lesion (3.51±0.61).

Conclusion

SSD images and thin-section spiral CT scans can provide valuable information for the evaluation of tracheobronchial disease.     

Anti-tumour effects of transcatheter arterial embolisation administered in combination with thalidomide in a rabbit VX2 liver tumour model

Objective

Using a liver tumour model we investigated whether thalidomide enhances the anti-tumour effect of transcatheter arterial embolisation (TAE).

Method

First, the viability of VX2 tumour cells co-cultured with thalidomide in a 21% and 1% O₂ atmosphere was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Second, we randomly assigned 20 rabbits bearing VX2 liver tumours to 4 groups: Group 1 (thalidomide plus TAE), Group 2 (TAE only), Group 3 (thalidomide only) and Group 4 (control). Thalidomide was orally administered for 5 days. The anti-tumour effects were assessed by the tumour proliferation rate using MRI and by immunohistochemical analysis of the area of intratumoural vessels. Analysis of variance and Tukey''s honestly significant difference test were used for statistical analysis.

Results

The viability of cells grown under hypoxic and normal conditions was not significantly different, nor was there a difference among the four groups. The tumour size increased by 55.9±29.3% in Group 1, 250.6±73.3% in Group 2, 355.2±51.7% in Group 3 and 424.7±110.7% in Group 4; the difference between Group 1 and the other three groups was significant. The area of intratumour vessels in specimens was 0.22±0.28% in Group 1, 0.42±0.29% in Group 2, 1.44±1.00% in Group 3 and 6.00±2.17% in Group 4; the difference between Group 1 and the other groups was statistically significant, as was the difference between Groups 3 and 4.

Conclusion

Thalidomide used in combination with TAE enhanced anti-tumour effects in rabbits bearing VX2 liver tumours.     

CT evaluation of the bony nasal pyramid dimensions in Anatolian people

Objectives

The aim of this study was to evaluate the nasal bone and bony nasal pyramid in adult Anatolian people.

Method

A total of 80 patients (48 males, 32 females, mean age of 40.03 years) were all evaluated using CT. Upper, intermediate and inferior thickness of the nasal bone on each side and on the lateral and medial osteotomy line were measured. In addition, nasal bone length and pyriform aperture width were determined.

Results

The bone thickness was 2.23 mm ± 0.15 mm in males and 2.19 mm ± 0.14 mm in females at the level of upper border of the nasal bone; 1.82 mm ± 0.32 mm in males and 1.81 mm ± 0.25 mm in females at the intermediate level; and 1.73 mm ± 0.30 mm in males and 1.86 mm ± 0.69 mm in females at the lower border of the nasal bone. The mean thickness on the lateral osteotomy line was 1.85 mm ± 0.32 mm in males and 1.91 mm ± 0.46 mm in females. The mean thickness of the medial osteotomy line was 2.08 ± 0.17 mm in males and 2.04 mm ± 0.17 mm in females. The mean length of the nasal bone was 30.61 mm ± 1.26 mm in males and 29.01 mm ± 1.12 mm in females. The mean width of the pyriform aperture was 18.83 mm ± 2.17 mm in males and 18.19 mm ± 1.85 in females.

Conclusion

The dimensions of the nasal pyramid are known to be important in the selection of appropriate osteotome. Our results can be used for pre-operative evaluation of Anatolian people undergoing nasal surgery.     

Expression Patterns of Glucose Transporter-1 Gene and Thyroid Specific Genes in Human Papillary Thyroid Carcinoma

Purpose

The expression of glucose transporter-1 (Glut-1) gene and those of major thyroid-specific genes were examined in papillary carcinoma tissues, and the expressions of these genes were compared with cancer differentiation grades.

Materials and Methods

Twenty-four human papillary carcinoma tissues were included in this study. The expressions of Glut-1- and thyroid-specific genes [sodium/iodide symporter (NIS), thyroid peroxidase, thyroglobulin, TSH receptor and pendrin] were analyzed by RT-PCR. Expression levels were expressed as ratios versus the expression of beta-actin. Pathologic differentiation of papillary carcinoma was classified into a relatively well-differentiated group (n = 13) and relatively less differentiated group (n = 11).

Results

Glut-1 gene expression was significantly higher in the less differentiated group (0.66 ± 0.04) than in the well-differentiated group (0.59 ± 0.07). The expression levels of the NIS, PD and TG genes were significantly higher in the well-differentiated group (NIS: 0.67 ± 0.20, PD: 0.65 ± 0.21, TG: 0.74 ± 0.16) than in the less differentiated group (NIS: 0.36 ± 0.05, PD: 0.49 ± 0.08, TG: 0.60 ± 0.11), respectively. A significant negative correlation was found between Glut-1 and NIS expression, and positive correlations were found between NIS and TG, and between NIS and PD.

Conclusion

The NIS, PD and TG genes were highly expressed in well-differentiated thyroid carcinomas, whereas the Glut-1 gene was highly expressed in less differentiated thyroid carcinomas. These findings provide a molecular rationale for the management of papillary carcinoma, especially in the selection of FDG PET or radioiodine whole-body scan and I-131-based therapy.     

Molecular MR Imaging for Visualizing ICAM-1 Expression in the Inflamed Synovium of Collagen-Induced Arthritic Mice

Objective

To determine the utility of intercellular adhesion molecule (ICAM)-1 antibody-conjugated gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA-anti-ICAM-1) as a targeted contrast agent for the molecular magnetic resonance imaging (MRI) in collagen-induced arthritis (CIA).

Materials and Methods

Three groups of mice were used: non-arthritic normal, CIA mice in both the early inflammatory and chronic destructive phases. The MR images of knee joints were obtained before and after injection of Gd-DTPA-anti-ICAM-1, Gd-DTPA, and Gd-DTPA-Immunoglobulin G (Ig G) and were analyzed quantitatively. The patterns of enhancement on the MR images were compared with the histological and immunohistochemical ICAM-1 staining.

Results

The images obtained after injection of Gd-DTPA-anti-ICAM-1 displayed gradually increasing signal enhancement from the moment following injection (mean ± standard deviation [SD]: 424.3 ± 35.2, n = 3) to 24 hours (532 ± 11.3), rather than on pre-enhanced images (293 ± 37.6) in the early inflammatory phase of CIA mice. However, signal enhancement by Gd-DTPA and Gd-DTPA-IgG disappeared after 80 minutes and 24 hours, respectively. In addition, no significant enhancement was seen in the chronic destructive phase of CIA mice, even though they also showed inflammatory changes on T2-weighted MR images. ICAM-1 expression was demonstrated in the endothelium and proliferating synovium of the early inflammatory phase of CIA mice, but not in the chronic destructive phase.

Conclusion

Molecular MRI with Gd-DTPA-anti-ICAM-1 displays specific images targeted to ICAM-1 that is expressed in the inflamed synovium of CIA. This novel tool may be useful for the early diagnosis and differentiation of the various stages of rheumatoid arthritis.     

Introducer Curving Technique for the Prevention of Tilting of Transfemoral G��nther Tulip Inferior Vena Cava Filter

Objective

To determine whether the introducer curving technique is useful in decreasing the degree of tilting of transfemoral Tulip filters.

Materials and Methods

The study sample group consisted of 108 patients with deep vein thrombosis who were enrolled and planned to undergo thrombolysis, and who accepted transfemoral Tulip filter insertion procedure. The patients were randomly divided into Group C and Group T. The introducer curving technique was Adopted in Group T. The post-implantation filter tilting angle (ACF) was measured in an anteroposterior projection. The retrieval hook adhering to the vascular wall was measured via tangential cavogram during retrieval.

Results

The overall average ACF was 5.8 ± 4.14 degrees. In Group C, the average ACF was 7.1 ± 4.52 degrees. In Group T, the average ACF was 4.4 ± 3.20 degrees. The groups displayed a statistically significant difference (t = 3.573, p = 0.001) in ACF. Additionally, the difference of ACF between the left and right approaches turned out to be statistically significant (7.1 ± 4.59 vs. 5.1 ± 3.82, t = 2.301, p = 0.023). The proportion of severe tilt (ACF ≥ 10°) in Group T was significantly lower than that in Group C (9.3% vs. 24.1%, χ² = 4.267, p = 0.039). Between the groups, the difference in the rate of the retrieval hook adhering to the vascular wall was also statistically significant (2.9% vs. 24.2%, χ² = 5.030, p = 0.025).

Conclusion

The introducer curving technique appears to minimize the incidence and extent of transfemoral Tulip filter tilting.     

Influence of individual brightness and contrast adjustment on accuracy of radiographic measurements of infrabony defects

Objectives

To assess the accuracy of radiographic measurements of infrabony defects and to compare the accuracy with and without individual digital adjustment of brightness and contrast.

Methods

In 41 periodontitis patients (19 females, 22 males; age range 23–73 years), 50 radiographs of 50 infrabony defects were obtained. All radiographs were digitized. Using a personal computer program, the linear distances between cemento-enamel junction (CEJ) and alveolar crest (AC) and between CEJ and bony defect (BD), and the depth of the infrabony defect (INFRA), were measured twice, according to the individual judgement of the radiographic examiner: (1) without digital adjustment (W) and (2) after use of contrast and brightness adjustment (A). Intrasurgical bone measurements served as the gold standard. The accuracy of measurements with or without digital adjustment was compared.

Results

Radiographic measurements underestimated the gold standard for CEJ-BD (W: 1.1 mm ± 1.8 mm, P < 0.001; A: 1.0 mm ± 1.9 mm, P = 0.001). Both CEJ-AC (W: 0.2 mm ± 2.5 mm; A: 0.5 mm ± 2.6 mm) and INFRA (W: −0.4 mm ± 2.4 mm; A: −0.6 mm ± 2.5 mm) measurements came close to the gold standard. Statistically significant differences between W and A regarding accuracy were not observed.

Conclusions

The measurement tool used in this study provided high-accuracy measurements of periodontal bone loss in INFRA. Individual brightness and contrast adjustment failed to improve accuracy.     

Interventional Management of Malignant Colorectal Obstruction: Use of Covered and Uncovered Stents

Objective

We wanted to evaluate usefulness of uncovered stent in comparison with covered stent for the palliative treatment of malignant colorectal obstruction.

Materials and Methods

Covered (n = 52, type 1 and type 2) and uncovered (n = 22, type 3) stents were placed in 74 patients with malignant colorectal obstruction. Stent insertion was performed for palliative treatment in 37 patients (covered stent: n = 23 and uncovered stent: n = 14). In the palliative group, the data on the success of the procedure, the stent patency and the complications between the two groups (covered versus uncovered stents) were compared.

Results

The technical success rate was 89% (33/37). Symptomatic improvement was achieved in 86% (18/21) of the covered stent group and in 92% (11/12) of the uncovered stent group patients. The period of follow-up ranged from three to 319 days (mean period: 116±85 days). The mean period of stent patency was 157±33 days in the covered stent group and 165±25 days in the uncovered stent group. In the covered stent group, stent migration (n = 11), stent fracture (n = 2) and poor expansion of the stent (n = 2) were noted. In the uncovered stent group, tumor ingrowth into the stents (n = 3) was noted.

Conclusion

Self-expanding metallic stents are effective for relieving malignant colorectal obstruction. The rate of complications is lower in the uncovered stent group than in the covered stent group.     

Optimization of Wet Radiofrequency Ablation Using a Perfused-Cooled Electrode: A Comparative Study in Ex Vivo Bovine Livers

Objective

To determine the optimized protocol for wet monopolar radiofrequency ablation (RFA) using a perfused-cooled electrode to induce coagulation necrosis in the ex vivo bovine liver.

Materials and Methods

Radiofrequency was applied to excised bovine livers in a monopolar mode using a 200W generator with an internally cooled electrode (groups A and B) or a perfused-cooled electrode (groups C, D, E, and F) at maximum power (150-200 W) for 10 minutes. A total of 60 ablation zones were created with six different regimens: group A - dry RFA using intra-electrode cooling; group B - dry RFA using intra-electrode cooling and a pulsing algorithm; group C - wet RFA using only interstitial hypertonic saline (HS) infusion; group D - wet RFA using interstitial HS infusion and a pulsing algorithm; group E - wet RFA using interstitial HS infusion and intra-electrode cooling; and group F - wet RFA using interstitial HS infusion, intra-electrode cooling and a pulsing algorithm. In groups C, D, E, and F, RFA was performed with the infusion of 6% HS through the perfused cooled electrode at a rate of 2 mL/minute. During RFA, we measured the tissue temperature at a distance of 15 mm from the electrode. The dimensions of the ablation zones and the changes in impedance, currents, and liver temperature during RFA were compared between these six groups.

Results

During RFA, the mean tissue impedances in groups A (243 ± 88 Ω) and C (252.5 ± 108 Ω) were significantly higher than those in groups B (85 ± 18.7 Ω), D (108.2 ± 85 Ω), E (70.0 ± 16.3 Ω), and F (66.5 ± 7 Ω) (p < 0.05). The mean currents in groups E and F were significantly higher than those in groups B and D, which were significantly higher than those in groups A and C (p < 0.05): 520 ± 425 mA in group A, 1163 ± 34 mA in group B, 652.5 ± 418 mA in group C, 842.5 ± 773 mA in group D, 1665 ± 295 mA in group E, and 1830 ± 109 mA in group F. The mean volumes of the ablation regions in groups E and F were significantly larger than those in the other groups (p < 0.05): 17.7 ± 5.6 cm³ in group A, 34.5 ± 3.0 cm³ in group B, 20.2 ± 15.6 cm³ in group C, 36.1 ± 19.5 cm³ in group D, 68.1 ± 12.4 cm³ in group E, and 79.5 ± 31 cm³ in group F. The final tissue temperatures at a distance of 15 mm from the electrode were higher in groups E and F than those in groups A, C, and D (p < 0.05): 50 ± 7.5℃ in group A, 66 ± 13.6℃ in group B, 60 ± 13.4℃ in group C, 61 ±12.7℃ in group D, 78 ± 14.2℃ in group E, and 79 ± 12.0℃ in group F.

Conclusion

Wet monopolar RFA, using intra-electrode cooling and interstitial saline infusion, showed better performance in creating a large ablation zone than either dry RFA or wet RFA without intra-electrode cooling.     

Percutaneous Radiofrequency Thermal Ablation with Hypertonic Saline Injection: In Vivo Study in a Rabbit Liver Model

Objective

To determine whether hypertonic saline (HS, 36% NaCl) injection prior to or during radiofrequency ablation (RFA) can increase the extent of thermally mediated coagulation in in-vivo rabbit liver tissue, and also to establish the ideal injection time in relation to RFA in order to maximize its effect on the extent of radiofrequency (RF)-induced coagulation.

Materials and Methods

In 26 rabbits, 43 RFA lesions were produced using a 17-gauge internally cooled electrode with a 1-cm active tip under ultrasound (US) guidance. Rabbits were assigned to one of three groups: Group A: RFA alone (n=8); Group B: RFA after the instillation of 1 mL HS (n=8); Group C: RFA after and during the instillation of 0.5 mL HS (n=10). RF energy (30 W) was applied for 3 minutes, and changes occurring in tissue impedance, current, power output, and the temperature of the electrode tip were automatically measured. After RFA, contrast-enhanced spiral CT was performed, and in each group the maximum diameters of the thermal lesions in gross specimens were compared. Technical success and the complications arising were evaluated by CT and on the basis of autopsy findings.

Results

All procedures were technically successful. There were six procedure-related complications (6/26; 23%), including five localized perihepatic hematomas and one thermal injury to the stomach. With instillation of HS in group B rabbits, markedly decreased tissue impedance (73Ω ± 5) and increased current (704 mA ± 41) were noted, compared to RF ablation without saline infusion (116.3Ω ± 13, 308 mA ± 80). With instillation of the solution before RFA (group B), coagulation necrosis was greater (14.9 mm ± 3.8) than in rabbits not injected (group A: 11.5 mm ± 2.4; Group A vs. B: p < .05) and in those injected before and during RFA (group C: 12.5 mm ± 3.1; Group B vs. C: p > .05).

Conclusion

RFA using HS instillation can increase the volume of RFA-induced necrosis of the liver with a single application, thereby simplifying and accelerating the treatment of larger lesions. In addition, HS instillation before RFA more effectively achieves coagulation necrosis than HS instillation before and during RFA.