Adel Maataoui

Navigation-Based Needle Puncture of a Cadaver Using a Hybrid Tracking Navigational System

Purpose:The purpose of this study was to determine the puncture accuracy of a navigational system, Medarpa, in a soft tissue environment using augmented overlay imaging. Materials and Methods:Medarpa is an optical electromagnetic tracking system, which allows tracking of instruments, the radiologist’s head position, and the transparent display. The display superimposes a computed tomography scan of a cadaver chest on a human cadaver in real time. In group A, needle puncture was performed using the Medarpa system. Three targets located inside the cadaver chest were selected. In group B, the same targets were used to perform standard computed tomography-guided puncture using a single-slice technique. A total of 42 punctures were performed in each group. Postpuncture computed tomography scans were made to verify needle tip positions. Results:Mean deviation from targets was 8.42 mm ± 1.78 mm for group A and 8.90 mm ± 1.71 mm for group B. No significant difference was found between group A and B in any target (P > 0.05). No significant difference was found between the targets of the same group (P > 0.05). Procedural time for 42 punctures was 160 minutes in group A versus 289 minutes in group B (P < 0.05). Conclusion:Needle puncture in a soft tissue environment using the navigational system Medarpa can be reliably performed and matches the accuracy achieved by a computed tomography-guided puncture technique.

Transarterial chemoembolization alone and in combination with other therapies: a comparative study in an animal HCC model

The purpose of this study is to compare transarterial chemoembolization (TACE) alone and in combination with other therapies in an animal model. Subcapsular implantation of a solid Morris hepatoma 3924A in the liver was carried out in 50 male ACI rats (day 0). Tumor volume (V1) was measured by MRI (day 13). After laparotomy and retrograde placement of a catheter into the gastroduodenal artery (day 14), the following protocols of the interventional procedure were applied: TACE (mitomycin C + lipiodol) + immunotherapy (group A: TNFα + IL-2, group B: OK-432 + IL-2); TACE + antiangiogenesis therapy (group C: TNP-470, group D: endostatin); TACE alone in group E (control group). Tumor volume (V2) was assessed by MRI and the mean ratio of x (V2/V1) was calculated. Data were analyzed using Dunnett’s t test (comparing therapeutic groups with the control group) and the Student-Newman-Keuls test (comparing significant therapeutic groups). Multivariate analysis showed a significant reduction in the tumor growth rate (P<0.05) in groups B (x=6.53) and C (x=4.01) compared to the mean ratio of the control group E (x=9.14). Significant results were observed in group C (P<0.05) in comparison with the other therapeutic groups. TACE combined with immunotherapy (OK-432) and antiangiogenesis therapy (TNP-470) retards tumor growth compared with TACE alone in an HCC animal model.

Visualisation of non-invasive coronary bypass imaging: 4-row vs. 16-row multidetector computed tomography

The purpose of this study was to investigate the image quality of coronary artery bypass graft visualization in 4- and 16-row multidetector CT using multiple imaging reformations. Material and Methods: One hundred sixteen patients underwent CT examination of the heart after receiving CABG. Group A (n=58) received 4-row MDCT; group B (n=58) received 16-row MDCT. Various bypass types such as LITA to LAD and venous grafts to the RCA and RCX were included in the study. A five-point Likert scale was used to grade image quality. Each bypass was reviewed under different imaging reformations: thin slap maximum intensity projection (MIP thin), multiplanar reformation (MPR) and volume rendering technique (VRT). Special attention was paid to the delineation of the distal anastomosis. Interobserver correlation was determined. Results: From 289 bypass grafts examined, 279 (96.54%) were classified as patent and 10 (3.46%) as not patent. Except for the distal anastomosis, 16-row MDCT showed significantly better results for all segments of bypasses. Comparison of reformations within group A and B showed that MIP thin (P<0.05) and VRT (P<0.05) displayed better visualization as compared to MPR. Conclusion: Significantly better imaging of all bypass types is possible using 16-row MDCT as compared to 4-row MDCT. Assessment of the distal anastomosis yields no difference between 4- and 16-row technology.

MDCT of the proximal anastomoses created by nitinol implants in coronary artery bypass grafting: a retrospective two-observer evaluation

The purpose of this study was to investigate the proximal anastomosis of CABG grafts created by a nitinol aortic connector. After receiving CABG, 33 patients underwent CT examination of the heart. On the same patients, CT was performed on postoperative day 5 (4-row CT, group A) and again 1 year thereafter (16-row CT, group B). Twenty-three ACVB to RCX and 27 ACVB to RCA grafts were included. Every anastomosis was reviewed under different reformations (MIP, MPR and VRT). Interobserver correlation was determined. Five days postoperatively, 48/50 anastomoses were classified as patent. One year postoperatively, 42/50 anastomoses were classified as patent. In both groups, the aortic connector could be visualized with good quality: 1.82±1.10 (group A) and 1.93±1.22 (group B) for ACVB to RCA, similar results for ACVB to RCX grafts (MPR). Image quality at the aortic connector site did not display a significant difference for any reformation between groups (P>0.05). Within groups, MPR displayed better visualization than MIP and VRT (P<0.05). In the presence of metal implants, CT provides reliable data in evaluation of the proximal anastomosis. Sixteen-row CT does not bring a significant benefit to image quality. MPR displayed the best visualization within both groups.

Correlation of lumbar lateral recess stenosis in magnetic resonance imaging and clinical symptoms

AIM To assess the correlation of lateral recess stenosis (LRS) of lumbar segments L4/5 and L5/S1 and the Oswestry Disability Index (ODI). METHODS Nine hundred and twenty-seven patients with history of low back pain were included in this uncontrolled study. On magnetic resonance images (MRI) the lateral recesses (LR) at lumbar levels L4/5 and L5/S1 were evaluated and each nerve root was classified into a 4-point grading scale (Grade 0-3) as normal, not deviated, deviated or compressed. Patient symptoms and disability were assessed using ODI. The Spearman’s rank correlation coefficient was used for statistical analysis (P < 0.05). RESULTS Approximately half of the LR revealed stenosis (grade 1-3; 52% at level L4/5 and 42% at level L5/S1) with 2.2% and 1.9% respectively reveal a nerve root compression. The ODI score ranged from 0%-91.11% with an arithmetic mean of 34.06% ± 16.89%. We observed a very weak statistically significant positive correlation between ODI and LRS at lumbar levels L4/5 and L5/S1, each bilaterally (L4/5 left: rho < 0.105, P < 0.01; L4/5 right: rho < 0.111, P < 0.01; L5/S1 left: rho 0.128, P < 0.01; L5/S1 right: rho < 0.157, P < 0.001). CONCLUSION Although MRI is the standard imaging tool for diagnosing lumbar spinal stenosis, this study showed only a weak correlation of LRS on MRI and clinical findings. This can be attributed to a number of reasons outlined in this study, underlining that imaging findings alone are not sufficient to establish a reliable diagnosis for patients with LRS.

Does therapist’s attitude affect clinical outcome of lumbar facet joint injections?

AIM To investigate if the clinical outcome of intra-articular lumbar facet joint injections is affected by the therapists attitude. METHODS A total of 40 patients with facet joint-associated chronic low back pain were randomly divided into two groups. All patients received computed tomography-guided, monosegmental intra-articular facet joint injections. Following the therapeutic procedure, the patients of the experimental group (EG) held a conversation with the radiologist in a comfortable atmosphere. During the dialog, the patients were encouraged to ask questions and were shown four images. The patients of the control group (CG) left the clinic without any further contact with the radiologist. Outcome was assessed using a pain-based Verbal Numeric Scale at baseline, at 1 wk and at 1, 3, and 6 mo after first treatment. RESULTS The patient demographics showed no differences between the groups. The patients of the EG received 57 interventional procedures in total, while the patients of the CG received 70 interventional procedures. In both groups, the pain scores decreased significantly over the entire observation period. Compared to the CG, the EG showed a statistically significant reduction of pain at 1 wk and 1 mo post-treatment, while at 3 and 6 mo after treatment, there were no significant differences between both groups. CONCLUSION Our results show a significant effect on pain relief during the early post-interventional period in the EG as compared to the CG. The basic principle behind the higher efficacy might be the phenomenon of hetero-suggestion.

Magnetic resonance imaging-based interpretation of degenerative changes in the lower lumbar segments and therapeutic consequences

Intervertebral disc degeneration and facet joint osteoarthritis of the lumbar spine are, among others, well known as a cause of low back and lower extremity pain. Together with their secondary disorders they set a big burden on health care systems and economics worldwide. Despite modern imaging modalities, such as magnetic resonance imaging, for a large proportion of patients with low back pain (LBP) it remains difficult to provide a specific diagnosis. The fact that nearly all the lumbar structures are possible sources of LBP, may serve as a possible explanation. Furthermore, our clinical experience confirms, that imaging alone is not a sufficient approach explaining LBP. Here, the Oswestry Disability Index, as the most commonly used measure to quantify disability for LBP, may serve as an easy-to-apply questionnaire to evaluate the patients ability to cope with everyday life. For therapeutic purposes, among the different options, the lumbar facet joint intra-articular injection of corticosteroids in combination with an anaesthetic solution is one of the most frequently performed interventional procedures. Although widely used the clinical benefit of intra-articular steroid injections remains controversial. Therefore, prior to therapy, standardized diagnostic algorithms for an accurate assessment, classification and correlation of degenerative changes of the lumbar spine are needed.

Facilitating cartilage volume measurement using MRI.

PURPOSE To compare quantitative cartilage volume measurement (CVM) using different slice thicknesses. MATERIALS AND METHODS Ten knees were scanned with a 1.5T MRI (Sonata, Siemens, Erlangen, Germany) using a 3D gradient echo sequence (FLASH, fast low-angle shot). Cartilage volume of the medial and lateral tibial plateau was measured by two independent readers in 1.5mm, 3.0mm and 5.0mm slices using the Argus software application. Accuracy and time effectiveness served as control parameters. RESULTS Determining cartilage volume, time for calculation diminished for the lateral tibial plateau from 384.6+/-127.7s and 379.1+/-117.6s to 214.9+/-109.9s and 213.9+/-102.2s to 122.1+/-60.1s and 126.8+/-56.2s and for the medial tibial plateau from 465.0+/-147.7s and 461.8+/-142.7s to 214.0+/-67.9s and 208.9+/-66.2s to 132.6+/-41.5s and 130.6+/-42.0s measuring 1.5mm, 3mm and 5mm slices, respectively. No statistically significant difference between cartilage volume measurements was observed (p>0.05) while very good inter-reader correlation was evaluated. CONCLUSION CVM using 1.5mm slices provides no higher accuracy than cartilage volume measurement in 5mm slices while an overall time saving up to 70% is possible.