Minor Structural Differences in the Cervical Spine Between Patients With Cervical Dystonia and Age-Matched Healthy Controls.

Background: Cervical dystonia is the most common form of focal dystonia. The frequency and pattern of degenerative changes of the cervical spine in patients with cervical dystonia and their relation to clinical symptoms remain unclear as no direct comparison to healthy controls has been performed yet. Here, we used magnetic resonance imaging (MRI) to investigate (1) whether structural abnormalities of the cervical spine are more common in patients with cervical dystonia compared to age-matched healthy controls, (2) if there are clinical predictors for abnormalities on MRI, and (3) to calculate the inter-rater reliability of the respective radiological scales. Methods: Twenty-five consecutive patients with cervical dystonia and 20 age-matched healthy controls were included in the study. MRI scans of the cervical spine were analyzed separately by three experienced raters blinded to clinical information, applying different MRI rating scales. Structural abnormalities were compared between groups for upper, middle, and lower cervical spine segments. The associations between scores differentiating both groups and clinical parameters were assessed in dystonia patients. Additionally, inter-rater reliability of the MRI scales was calculated. Results: Comparing structural abnormalities, we found minor differences in the middle cervical spine, indicated by a higher MRI total score in patients but no significant correlation between clinical parameters and MRI changes. Inter-rater reliability was satisfying for most of the MRI rating scales. Conclusion: Our results do not provide evidence for a role of MRI of the cervical spine in the routine work-up of patients with cervical dystonia in the absence of specific clinical signs or symptoms.

Successful Retrieval of an Embolized Vascular Closure Device (Angio-Seal®) After Peripheral Angioplasty.

A 55-year-old male with peripheral arterial disease underwent angioplasty of the right lower limb arteries via antegrade femoral access. Angio-Seal® closure device was used to treat the puncture site, whereby the intravascular sealing anchor accidentally embolized into the malleolar region of the right posterior tibial artery. Successful retrieval of the anchor was accomplished by a SpiderFX embolic protection device. This technique may be a useful approach to retrieve embolized foreign bodies via endovascular access.

First pass dual input volume CT-perfusion of lung lesions: The influence of the CT- value range settings on the perfusion values of benign and malignant entities.

OBJECTIVE: To assess the influence of the lower threshold for segmentation of the volume of interest on the perfusion values in first-pass dual input volume CT-perfusion of lung lesions. MATERIALS AND METHODS: Dual input maximum slope volume CT-perfusion was performed in 48 patients (mean age±standard deviation [SD], 68±10years; range, 46-87 years) who underwent subsequent CT-guided biopsy to evaluate a lung lesion. Using commercial perfusion software, a lower and upper threshold was set for determination of the CT-value range, which again determined the volume of interest for perfusion calculation. The pulmonary arterial flow (PAF), bronchial arterial flow (BAF), and perfusion index (PI; PAF/(PAF+BAF)) were calculated at following pre contrast CT value range settings: -80 to 150HU (setting 1), -200 to 150HU (setting 2), -300 to 150HU (setting 3), and -500 to 150HU (setting 4). Perfusion parameters were compared between benign (n, 15) and malignant (n, 33) lesions for each setting. Intraobserver- and interobserver reliability were calculated for setting 4. RESULTS: Median PAF was significantly higher in malignant lesions than in benign lesions for all settings (53-96 versus 29-62mL/min/100mL, P<0.05). There was no significant difference in BAF between malignant and benign lesions. Median PAF of all lesions was significantly influenced by the CT value range setting (P<0.05), whereas the values increased from setting 1 to 4. Intraobserver analysis as well as interobserver analysis of PAF at setting 4 showed excellent reliability (Cronbach's alpha 0.98 and 0.95, respectively, P<0.01). CONCLUSION: PAF derived from first-pass dual-input maximum slope volume CT perfusion is statistically significantly higher in malignant than in benign lesion, whereas the measurements are influenced by the lower threshold of the CT value range setting. This has to be considered when using cutoff values provided in the literature for differentiation between benign and malignant lung lesions.

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.

Placement of hemoparin-coated stents in the iliac arteries: early experience and midterm results in 28 patients.

PURPOSE: Aim was to determine immediate results and mid-term outcome of the hemoparin-coated (HC) stainless-steel stent (camouflage coating) in the treatment of occlusive lesions of the iliac arteries. MATERIALS AND METHODS: Twenty-eight patients were prospectively treated with the use of a HC stent between January 2007 and March 2010. Clinical examination and color-doppler ultrasound were performed at 1, 3, 6 and 12 months, CT angiography (CTA) or MR angiography (MRA) at 12 months. Indication for treatment was a high-grade stenosis of the common iliac and/or external iliac artery. RESULTS: Successful placement was achieved in all patients. Significant decrease in translesional pressure gradient (>10 mm Hg) was measured in 27 patients (96%). In one patient, proximal dissection occurred without flow limitation. A minor complication (small access site hematoma) occurred in one patient (4%). Two patients (7%) were lost to follow-up. After 12 months, stent patency in CTA, MRA and ultrasound was 100%. 20 patients (77%) experienced an initial improvement of at least one clinical stage. In one patient (4%), mild intimal hyperplasia without significant stenosis was observed. In three patients (12%), proximal or distal stenosis occurred. A non-significant increase of mean ankle-brachial index (ABI) after treatment was measured (0.85 ± 0.27 vs. 0.75 ± 0.22, respectively; p=0.328). CONCLUSIONS: The use of HC stents in patients with iliac artery occlusive disease may lead to a lower rate of intimal hyperplasia and thus to increased patency rates even in heavily calcified vessels. However, large-scale prospective trials have to be performed to evaluate the long-term patency rates of the HC coated stents.

A HLA-Cw6 specific single-chain antibody fragment (scFv) recognizing a natural killer cell receptor epitope.

Major histocompatibility complex (MHC) class I molecules induce inhibitory signals on natural killer (NK) cells via killer cell immunoglobulin-like receptors (KIR). We recently reported a human single-chain antibody (scFv#1), which recognizes an epitope on HLA-Cw6 (genotype: *0602). Flow cytometry showed scFv#1 binding to HLA-Cw6 (strong) and also to HLA-Cw2, 4, 5 (very weak) but not to HLA-Cw1, 3, 7, 8. The presumptive epitope of the antibody fragment, which includes residues Asn77 and Lys80 was verified by introducing point mutations into HLA-Cw6 encoding cDNAs. Asn77 --> Ser77 (N77S) and Lys80- -> Asn80 (K80N) mutants of Cw6 lost scFv#1 binding capacity whereas an additional mutation at aa position 90 (Asp-->Ala, D90A) did not influence scFv#1 binding characteristics. Since residues 77 and 80 of HLA-C are directly involved in KIR/MHC interaction, we expected the induction of target cell lysis upon addition of scFv#1 when bringing NK and HLA-Cw6 positive cells together. To prove this interference, we performed Cr-release assays, using Cw*0602 and mock-transfected K562 erythroleukemia cells as targets and freshly prepared peripheral blood NK cells as effector cells. scFv#1 appeared to influence KIR on ligand binding and restored lysis at low effector to target (E/T) ratios. Pan HLA class I antibody W6/32 did not show such effects. Taken together scFv#1 binding patterns with mutagenized HLA-Cw6 and Cr-release assays are strong evidence that the scFv#1 epitope on HLA-Cw6 is at or close to the binding site of CD158a.