Correlation of (99m) Tc-DPD SPECT/CT Scan Findings and Diagnostic Blockades of Lumbar Medial Branches in Patients with Unspecific Low Back Pain in a Randomized-Controlled Trial.

OBJECTIVE: Zygapophyseal joints are the origin of pain in up to 30% of those with unspecific chronic low back pain. Until recently, no reliable clinical tests have been found to identify the patients who would benefit from denervation of the zygapophyseal joints by medial branch blockades. DESIGN: We performed a prospective randomized placebo-controlled trial to evaluate the value of high-resolution single-photon emission computed tomography (SPECT)/computed tomography (CT) of the lumbar spine prior to any diagnostic infiltration of the medial branches. METHODS: Patients with suspected zygapophyseal joint-related pain were included in the study. After obtaining a SPECT/CT scan of the lumbar spine a set of infiltrations of the medial branches was done with local anesthetics and placebo on different days. Patients and anesthetists were blinded to the results of SPECT/CT and to the infiltrated agents. RESULTS: In a total of 29 study patients, 7 had positive and 22 negative infiltration tests, and 9 had positive and 20 negative SPECT/CT findings. Sensitivity of SPECT/CT for a positive response after diagnostic infiltration was 0.57 (95% confidence interval [CI] 0.18-0.90); specificity was 0.77 (CI 95% 0.55-0.92); odds ratio was 4.53 (CI 95% 0.75-27.40); and diagnostic accuracy was 0.72. CONCLUSION: Compared with diagnostic infiltrations SPECT/CT scans showed only a moderate sensitivity and specificity and, therefore, may not be recommended as a first line diagnostic tool prior to diagnostic infiltrations.

Impact of an intensive 2-day endovascular training course on technical performance of trainees.

BACKGROUND: The objective of this study was to evaluate the effect of a 2-day international endovascular training course on the performance of trainees as compared with a control group, assessed in a bench model-based task using an objective structured evaluation protocol. METHODS: A total of 50 trainees, 28 course participants of 2 consecutive identical courses and a control group of 22 participants with a similar level of experience without course attendance, underwent baseline and final assessment (simulated arterial access task). The evaluation form consisted of a global assessment (GA), task-specific checklist percentage score (CL), and global rating scale percentage score (GR), with both percentage scores ranging from 0% (worst performance) to 100% (best performance). RESULTS: Course participants were more likely to pass the GA at final testing than the control group (odds ratio=59; 95% confidence interval [CI] 9.5-656; P<0.001). The estimated difference in percentage score at final testing between course participants and the control group was 26% (95% CI 18-34; P<0.001) for the CL and 29% (95% CI 19-40; P<0.001) for the GR. CONCLUSIONS: A 2-day structured endovascular training course significantly improves endovascular performance in a simulated environment. These results are important for the design of endovascular training curricula with the ultimate goal of contributing to patient safety.

ECG-triggered non-enhanced MR angiography of peripheral arteries in comparison to DSA in patients with peripheral artery occlusive disease.

OBJECT: The purpose of this study was to evaluate peripheral non-enhanced-MRA (NE-MRA) acquired with a 3D Turbo Spin Echo sequence with electrocardiographt (ECG) triggering in comparison to Digital Subtraction Angiography (DSA) as the gold standard in symptomatic peripheral artery occlusive disease (PAOD) patients. MATERIALS AND METHODS: This IRB approved prospective study included 23 PAOD patients from whom three patients had to be excluded. The remaining 20 subjects were included in the analysis (15 male; mean age 62.4 ± 15.3 years). The patients first underwent DSA followed by NE-MRA on a 1.5-T whole body scanner within 24 h after the DSA study. A NATIVE (Non-contrast Angiography of the Arteries and Veins) SPACE (Sampling Perfection with Application Optimized Contrast by using different flip angle Evolution) sequence at four levels (pelvis, upper leg, knee region and lower leg) was acquired. For evaluation purposes, subtracted standardized MIP (maximum intensity projection) images were generated from the NE-MRA data sets. Qualitative assessment of NE-MRA images in reference to the corresponding DSA images, as well as blinded stenosis grading of preselected segments in NE-MRA images were performed by two experienced readers. Image quality in 95 corresponding arterial segments was rated from 1 (good) to 4 (inadequate) directly comparing the NE-MRA with the corresponding DSA segment as the gold standard. Blinded stenosis grading consisted of 66 preselected stenoses rated from 1 (<10 %) to 4 (>90 %) in NE-MRA which were compared to the grade in the corresponding DSA. RESULTS: The mean image quality of NE-MRA in comparison to DSA was 2.7 ± 1.1 (reader 1) and 3.0 ± 1.0 (reader 2). The kappa value indicating interobserver agreement was 0.34; readers 1 and 2 rated the image quality as good in 21 % and 3 %, sufficient in 19 % and 41 %, limited in 29 % and 14 % and inadequate in 31 % and 42 %, respectively. Stenosis graduation revealed significantly higher grades in NE-MRA (reader 1: 3.0 ± 0.7, p < 0.001 and reader 2: 3.1 + 0.8, p < 0.001) compared to DSA (mean value DSA 2.7 ± 0.8). The kappa value indicating interobserver agreement concerning stenosis grading was 0.59. CONCLUSION: NE-MRA revealed a relatively high number of inadequate quality segments. This is in line with recently published comparable studies of the similar SPACE NE-MRA techniques. Further advance of NE-MRA techniques remains desirable for patients with PAOD.

Percutaneous foot joint needle placement using a C-arm flat-panel detector CT.

PURPOSE: Image guidance is valuable for diagnostic injections in foot orthopaedics. Flat-detector computed tomography (FD-CT) was implemented using a C-arm, and the system was tested for needle guidance in foot joint injections. METHODS: FD-CT-guided joint infiltration was performed in 6 patients referred from the orthopaedic department for diagnostic foot injections. All interventions were performed utilising a flat-panel fluoroscopy system utilising specialised image guidance and planning software. Successful infiltration was defined by localisation of contrast media depot in the targeted joint. The pre- and post-interventional numeric analogue scale (NAS) pain score was assessed. RESULTS: All injections were technically successful. Contrast media deposit was documented in all targeted joints. Significant relief of symptoms was noted by all 6 participants. CONCLUSIONS: FD-CT-guided joint infiltration is a feasible method for diagnostic infiltration of midfoot and hindfoot joints. The FD-CT approach may become an alternative to commonly used 2D-fluoroscopically guidance.

Pain in osteochondral lesions.

Pain is the key symptom of patients suffering from osteochondral lesions (OCLs) of the ankle joint. Routine radiographic imaging methods for diagnosis and staging of OCL fail to visualize the pain-inducing focus within the joint. SPECT-CT (Single-photon emission computed tomography-computed tomography) is a new hybrid imaging technique allowing exact digital fusion of scintigraphic and computer tomographic images. This allows precise localization and size determination of an OCL within the joint. Using this novel imaging method, we conducted a study to evaluate the correlation between pathological uptake within an OCL and pain experienced by patients suffering from this condition; 15 patients were assessed in the orthopaedic ambulatory clinic for unilateral OCL of the ankle joint. Pain status was measured with the Visual Analogue Scale (VAS). A SPECT-CT was performed. All patients underwent CT-guided ankle injection with a local anesthetic and iodine contrast medium. The VAS score assessed immediately postinfiltration was compared with the preinterventional VAS score obtained in the outpatient clinic. Pain relief was defined as a reduction of the VAS score to ≤50% of the preinterventional score, if expected immediately after infiltration. Pain relief was found in all 15 patients. The results of our study show that there is a highly significant correlation between pain and pathological uptake seen on SPECT-CT, indicating that pathologically remodeled bone tissue is an important contributor to pain in OCL. Adequate addressing of involved bone tissue needs to be taken into consideration when choosing a surgical treatment method.

Prognostic value of Sequential Organ Failure Assessment and Simplified Acute Physiology II Score compared with trauma scores in the outcome of multiple-trauma patients.

BACKGROUND: Prospective data regarding the prognostic value of the Sequential Organ Failure Assessment (SOFA) score in comparison with the Simplified Acute Physiology Score (SAPS II) and trauma scores on the outcome of multiple-trauma patients are lacking. METHODS: Single-center evaluation (n = 237, Injury Severity Score [ISS] >16; mean ISS = 29). Uni- and multivariate analysis of SAPS II, SOFA, revised trauma, polytrauma, and trauma and ISS scores (TRISS) was performed. RESULTS: The 30-day mortality was 22.8% (n = 54). SOFA day 1 was significantly higher in nonsurvivors compared with survivors (P < .001) and correlated well with the length of intensive care unit stay (r = .50, P < .001). Logistic regression revealed SAPS II to have the best predictive value of 30-day mortality (area under the receiver operating characteristic = .86 +/- .03). The SOFA score significantly added prognostic information with regard to mortality to both SAPS II and TRISS. CONCLUSIONS: The combination of critically ill and trauma scores may increase the accuracy of mortality prediction in multiple-trauma patients.

Simultaneous dynamic blood oxygen level-dependent magnetic resonance imaging of foot and calf muscles: aging effects at ischemia and postocclusive hyperemia in healthy volunteers.

PURPOSE: To demonstrate the feasibility of simultaneous blood oxygen level-dependent (BOLD) magnetic resonance imaging of calf and foot muscles and investigate age-related changes of BOLD signal changes during ischemia and postocclusive hyperemia in healthy volunteers. MATERIAL AND METHODS: In this study, 15 healthy elderly volunteers (mean age: 69.0 +/- 7.4 years) and 15 healthy young volunteers (mean age: 26.1 +/- 3.9 years) were enrolled. In both legs, simultaneous BOLD imaging of calf and foot muscles was performed at 1.5 Tesla. Short-term ischemia and consecutive reactive hyperemia were provoked by a cuff-compression paradigm. T2*-weighted signal time courses were obtained from foot and calf muscles simultaneously. Ischemia was assessed by T2* minimum ischemic value (MIV) and the time to half ischemic minimum (THIM). Reperfusion was assessed by the time to reach T2* half hyperemia peak (THHP). Reactive hyperemia was characterized by hyperemia peak value (HPV), time to peak (TTP), and relative T2* change from end of ischemia to HPV (deltaS). Parameter differences were assessed using a 2-sided Student t test. RESULTS: Dynamic BOLD measurement of foot and calf muscles was techniqually feasible and successful in all volunteers.In comparison, THIM was significantly longer in elderly than in young volunteers for calf (P < 0.01) muscles (young: 28.9 +/- 3.7 seconds; elderly: 57.8 +/- 31.4 seconds) and foot (P = 0.01) muscles (young: 36.8 +/- 25.5 seconds; elderly: 56.6 +/- 31.7 seconds). MIV relative to baseline T2*-signal was significantly (P < 0.01) lower in the elderly for calf (young: 96.0% +/- 2.6%; elderly: 91.3% +/- 4.4%) and foot (young: 95.8% +/- 2.5%; elderly: 91.1% +/- 8.2%) muscles. TTP was significantly (calf: P = 0.01; foot: P = 0.02) delayed in the elderly (elderly calf: 103.0 +/- 92.7 seconds and foot: 157.1 +/- 109.9 seconds vs. young calf: 54.8 +/- 42.1 seconds and foot: 95.1 +/- 77.6 seconds). HPV was significantly (calf: P < 0.01 and foot: P = 0.03) higher in (young calf: 114.1% +/- 7.2% and foot: 105.8% +/- 3.3% vs. elderly calf: 104.0% +/- 2.1% and foot: 103.9% +/- 3.2% seconds) young volunteers.In a muscle-group comparison, no significant differences in THIM and MIV were observed between calf and foot.THHP was significantly (P = 0.02) longer in foot muscles (foot young: 32.5 +/- 29.8 seconds and elderly: 34.1 +/- 25.0 seconds vs. calf young: 16.8 +/- 14.1 seconds and elderly: 23.6 +/- 14.1 seconds) of both age groups. TTP was significantly (P = 0.01 and 0.02) longer in foot muscles (foot young: 95.1 +/- 77.6 seconds and elderly: 157.1 +/- 109.9 seconds vs. calf young: 54.8 +/- 42.1 seconds and elderly: 103.0 +/- 92.7 seconds) of both age groups. HPV was lower (P < 0.01) in foot muscles of the young (calf: 114.1% +/- 7.2% vs. foot: 105.8 +/- 3.3%). CONCLUSION: Simultaneous BOLD-imaging of calf and foot muscles is feasible and reveals statistically significant age-related differences during ischemia and postocclusive hyperemia in healthy volunteers.

CT-guided robotically-assisted infiltration of foot and ankle joints.

It was our aim to describe a CT-guided robotically-assisted infiltration technique for diagnostic injections in foot and ankle orthopaedics. CT-guided mechatronically-assisted joint infiltration was performed on 16 patients referred to the orthopaedic department for diagnostic foot and ankle assessment. All interventions were performed using an INNOMOTION-assistance device on a multislice CT scanner in an image-guided therapy suite. Successful infiltration was defined as CT localization of contrast media in the target joint. Additionally, pre- and post-interventional VAS pain scores were assessed. All injections (16/16 joints) were technically successful. Contrast media deposit was documented in all targeted joints. Significant relief of pain was noted by all 16 patients (p<0.01). CT-guided robotically-assisted intervention is an exact, reliable and safe application method for diagnostic infiltration of midfoot and hindfoot joints. The high accuracy and feasibility in a clinical environment make it a viable alternative to the commonly used fluoroscopic-guided procedures.

Dynamic magnetic resonance angiography of the arteries of the hand. A comparison between an extracellular and an intravascular contrast agent.

The purpose of this study was to compare the image quality of the intravascular contrast agent gadofosveset with the extracellular contrast agent gadoterate meglumine in time-resolved three-dimensional magnetic resonance (MR) angiography of the human arteries of the hand. The value of cuff compression technique for suppression of venous enhancement for both contrast agents was also investigated. Three-dimensional MR angiograms of both hands of 11 healthy volunteers were acquired for each contrast agent at 1.5-T, while subsystolic cuff compression was applied at one side. Quantitative and qualitative evaluation were performed and analyzed with Student's t-test. Visualization of vessels was superior in the images acquired with gadofosveset, especially in the late phases. Quantitative and qualitative evaluation showed significantly higher values for gadofosveset. The cuff compression at the lower arm proved to be an effective method to enhance arterial vessels. In conclusion the blood pool agent gadofosveset is superior for the dynamic imaging of the vessels of the hand when compared with the extracellular contrast agent gadoterate meglumine. To fully utilize the advantages of intravascular contrast agents, venous overlay has to be delayed or reduced, which can be achieved effectively by subsystolic lower arm cuff compression.

A CT database for research, development and education: concept and potential.

Both in radiology and in surgery, numerous applications are emerging that enable 3D visualization of data from various imaging modalities. In clinical practice, the patient's images are analyzed on work stations in the Radiology Department. For specific preclinical and educational applications, however, data from single patients are insufficient. Instead, similar scans from a number of individuals within a collective must be compiled. The definition of standardized acquisition procedures and archiving formats are prerequisite for subsequent analysis of multiple data sets. Focusing on bone morphology, we describe our concept of a computer database of 3D human bone models obtained from computed tomography (CT) scans. We further discuss and illustrate deployment areas ranging from prosthesis design, over virtual operation simulation up to 3D anatomy atlases. The database of 3D bone models described in this work, created and maintained by the AO Development Institute, may be accessible to research institutes on request.

A faster method for 3D/2D medical image registration--a simulation study.

3D/2D patient-to-computed-tomography (CT) registration is a method to determine a transformation that maps two coordinate systems by comparing a projection image rendered from CT to a real projection image. Iterative variation of the CT's position between rendering steps finally leads to exact registration. Applications include exact patient positioning in radiation therapy, calibration of surgical robots, and pose estimation in computer-aided surgery. One of the problems associated with 3D/2D registration is the fact that finding a registration includes solving a minimization problem in six degrees of freedom (dof) in motion. This results in considerable time requirements since for each iteration step at least one volume rendering has to be computed. We show that by choosing an appropriate world coordinate system and by applying a 2D/2D registration method in each iteration step, the number of iterations can be grossly reduced from n6 to n5. Here, n is the number of discrete variations around a given coordinate. Depending on the configuration of the optimization algorithm, this reduces the total number of iterations necessary to at least 1/3 of it's original value. The method was implemented and extensively tested on simulated x-ray images of a tibia, a pelvis and a skull base. When using one projective image and a discrete full parameter space search for solving the optimization problem, average accuracy was found to be 1.0 +/- 0.6(degrees) and 4.1 +/- 1.9 (mm) for a registration in six parameters, and 1.0 +/- 0.7(degrees) and 4.2 +/- 1.6 (mm) when using the 5 + 1 dof method described in this paper. Time requirements were reduced by a factor 3.1. We conclude that this hardware-independent optimization of 3D/2D registration is a step towards increasing the acceptance of this promising method for a wide number of clinical applications.

Stenting for pulmonary artery stenosis due to a recurrent primary leiomyosarcoma.

PURPOSE: To report stent implantation for a malignant obstruction within the pulmonary artery (PA) caused by a recurrent leiomyosarcoma in the pulmonary trunk. CASE REPORT: A 62-year-old man with a non-metastatic primary leiomyosarcoma of the right PA underwent pneumectomy of the right lung and postoperative radiotherapy in 1994. Six years later, he presented with symptoms of progressive right ventricular dysfunction. Computed tomography (CT) identified a high-grade stenosis of the left PA due to recurrent tumor within the pulmonary trunk extending into the left PA. Transthoracic ultrasound documented severe pulmonary hypertension with a high pressure gradient across the stenosis. A stent was deployed percutaneously, successfully establishing PA patency. Pressure measurements showed a significantly reduced gradient across the stented area. In follow-up, the patient reported subjective improvement of symptoms; CT scans revealed a fully patent stent. His status remained stable 11 months after stent implantation. CONCLUSIONS: PA leiomyosarcoma is a rare and highly malignant tumor. In most cases, surgery can only prolong survival for the short term. Palliative interventional PA stenting performed under local anesthesia can offer improvement in quality of life by reducing excessive pulmonary hypertension.

CT-guided percutaneous embolization of a lumbar artery maintaining a type II endoleak.

PURPOSE: To demonstrate the possibility of percutaneous embolization of a type II endoleak guided by computed tomographic (CT) fluoroscopy. CASE REPORT: A type II endoleak maintained by a hypertrophic fourth lumbar artery failed to occlude spontaneously 7 months after stent-graft deployment for endovascular repair of an infrarenal abdominal aortic aneurysm. A percutaneous procedure was performed to eliminate the endoleak using needle puncture and embolization under CT fluoroscopic guidance. The sagittal diameter of the aneurysm sac, which had remained constant after initial endovascular exclusion, shrank from 5.2 to 4.8 cm in the 3 months following embolization. CONCLUSIONS: Percutaneous embolization of lumbar branches guided by CT fluoroscopy may be an alternative to other therapies for type II endoleaks.