Dietrich H W Groenemeyer

Comparison of Electron Beam Computed Tomography With Intracoronary Ultrasound and Coronary Angiography for Detection of Coronary Atherosclerosis

OBJECTIVES This analysis compared the results of electron beam computed tomography (EBCT) with those of coronary angiography and intracoronary ultrasound (ICUS) for the in vivo detection of coronary atherosclerotic plaques. BACKGROUND EBCT is a new imaging modality for identification of coronary calcifications. Coronary angiography depicts advanced changes in coronary morphology, whereas ICUS is an established diagnostic tool that detects the early stages of coronary artery disease. METHODS In 57 patients (54 +/- 9 years old), 267 coronary segments were analyzed with EBCT (3-mm slices, acquisition time 100 ms, threshold definition of coronary calcification at 130 Hounsfield units in an area > or = 1 mm2, Agatston calcium score), coronary angiography and ICUS. The analysis was based on the number and extent of coronary calcifications on EBCT, coronary lumen reduction on coronary angiography and plaque formation with and without ultrasound signs of calcifications on ICUS. RESULTS Compared with coronary angiography, EBCT yielded a sensitivity of 66%, a specificity of 78%, a positive predictive value of 39% and a negative predictive value of 91%. Compared with ICUS, EBCT yielded an overall sensitivity of 66%, a specificity of 88% and an overall accuracy of 81%. For plaques with and without ultrasound signs of calcifications, the sensitivity of EBCT was 97% and 47%, specificity 80% and 75% and overall accuracy 82% and 69%, respectively. CONCLUSIONS This in vivo correlation between ICUS and EBCT demonstrates that EBCT is a noninvasive method that helps to visualize the atherosclerotic process by localization and quantification of coronary artery calcifications. EBCT detects calcified plaques with high accuracy. Plaques without ultrasound signs of calcifications can be detected by EBCT but with lower sensitivity but equivalent specificity.

A novel Laser Navigation System reduces radiation exposure and improves accuracy and workflow of CT-guided spinal interventions: A prospective, randomized, controlled, clinical trial in comparison to conventional freehand puncture

PURPOSE Phantom model evaluation and prospective randomized clinical trial to assess the clinical feasibility and benefit of using a novel Laser Navigation System (LNS) in CT-guided epidural and perineural injections in comparison to the conventional freehand procedure. METHODS The LNS guided puncture technique was compared to the standard CT-guided freehand treatment using a phantom model and a randomized clinical trial. Spinal injections were administered by an experienced interventional team to evaluate needle placement accuracy, treatment time and radiation exposure. RESULTS In the LNS group of the phantom model study, the needle entrance point accuracy of 0.5mm (freehand 3.1mm), needle target point accuracy of 2.0mm (freehand 3.5mm), number of control CT slices of 1.4 (freehand 2.7) and needle placement time of 5min 4s (freehand: 9min 18s) showed significant improvements compared to freehand in 60 punctures. In the clinical trial the LNS group achieved needle entrance point accuracy of 1.3mm (freehand 4.6mm), needle angulation accuracy of 0.4° (freehand 2.3°), number of control CT slices of 1.1 (freehand 1.8) and needle placement time of 6min 54s (freehand 9min 00s), showing significant improvements compared to freehand in a total of 58 CT-guided interventions. CONCLUSION The LNS group showed significantly improved results in both study designs. Both the phantom model evaluation and the clinical trial of spinal injections showed feasibility and efficacy of using the novel LNS. Even an experienced interventional team worked with it more precise, faster and with reduced radiation exposure.

Localization of acupuncture points BL25 and BL26 using computed tomography.

OBJECTIVES The aim of this study was to provide a metric description of acupuncture points BL25 and BL26, to investigate their relation to individual anatomical landmarks and structures, and to identify anatomical structures that are involved in needle manipulation during de qi. DESIGN Fifty-eight (58) white patients with low-back pain received 107 needlings that were documented using computed tomography (CT). OUTCOME MEASURES For each patient, the body-mass index (BMI) and the interscapular distance were measured. Using the CT scan, the following parameters were assessed: thickness of the soft tissue layer, distance of the puncture site and the needle tip to the vertebral line, distance of the needle tip to the body surface and the intermuscular space, and the needle depth in muscle tissue. RESULTS The mean distance from the puncture site to the vertebral line was 3.5 +/- 0.5 cm for BL25 and 3.4 +/- 0.4 cm for BL26. The distance of the needle tip to the vertebral line was similar (3.4 +/- 0.5 cm for BL25 and 3.2 +/- 0.4 cm for BL26). The mean distance of the needle tip to the body surface was 4.1 +/- 0.9 cm at BL25 and 3.9 +/- 0.8 cm at BL26. The majority of the needle tips were located in the intermuscular region between the erector spinae and the transversospinal muscles. There was a significant correlation between the interscapular distance and the thickness of the soft tissue layer with the BMI at both acupuncture points. Nearly all parameters correlated with the BMI. At BL26, correlations between the distance of needle to the vertebral line and the BMI were not statistically significant but the scatter plots indicate a positive dependency. CONCLUSIONS The results of this study show an association between de qi and needle location within the intermuscular septa. BL25 and BL26 are located as clusters in and around the intermuscular region of the erector spinae and the transversospinal muscles, with a distance to the vertebral line of 3.49 +/- 0.58 cm and 3.32 +/- 0.53 cm, respectively. Using proportional methods is relevant for the success of acupuncture therapy.

Computed Tomography-guided Periradicular Injections on Cervical and Lumbar Spine

Treating sciatic pain caused by intervertebral disk herniation remains challenging. Not only does the symptomatology put a strain on patients, it is also of enormous socioeconomic impact. Next to conservative measures that include physical therapy and adequate pain medication, surgery—absolutely indicated in cases of cauda syndrome and severe motor deficit—seems to be the treatment of choice. In some cases though surgery seems to have identical long-term results compared with conservative management. Yet, neither conservative measures nor surgery always provide sufficient results. Moreover, there are a number of patients who do on the one hand not respond to conservative therapy, but do on the other hand not have the indication for surgery. As a result alternative, minimally invasive, image-guided therapies, such as periradicular therapy, have been introduced in recent years. Periradicular therapy is indicated in patients with radicular pain symptoms or radiculopathy, which may be caused by foraminal or spinal canal stenosis, tumors, or spondylolisthesis, and has become popular in the treatment of lumbar radicular complaints due to disk herniation. This review article focusses on different aspects of CT-guided periradicular injections and emphasizes a selection of practical considerations of important interventions at different spinal regions.

Interventional CT and MRI: a challenge for safety and cost reduction in the health care system

For increasing safety in guidance techniques of endoscopes and instruments, fast radiologic imaging should be integrated. Magnetic resonance imaging (MRI), computer tomography (CT) and electron beam tomography (EBT) scanners permit transparency of the operative field; CT and EBT can be combined with fluoroscopy and ultrasound units. MRI avoids x ray exposure, but entails the possibility for 3 D localization. Open access and keyhole imaging allows nearly real time guidance of instruments. Combining minimally invasive techniques using endoscopes and tomographic guidance these technologies improve surgical access and reduce complications. This offers a safe access into the body and leads to the new field of interventional and surgical tomography. Important cost reduction for health care systems is possible, especially in the outpatient treatment of common diseases like disk herniation, back and tumor pain, metastasis, or arteriosclerosis. For realizing a long term cost reduction effect, these techniques have to be integrated in a quality management combining prevention, modern diagnosis, minimal access techniques and, if necessary, hospital stay with maximal access treatments as well as rehabilitation and secondary/tertiary prevention.