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G Heidrich

Publications and source records attributed to G Heidrich.

17 recordsLinked to original sources
PubMed2006

The interobserver-validated relevance of intervertebral spacer materials in MRI artifacting.

Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post-fusion MRI scans. Implant-related susceptibility artifacts can decrease the quality of MRI scans, thwarting proper evaluation. This cadaver study aimed to demonstrate the extent that implant-related MRI artifacting affects the post-fusion evaluation of intervertebral spacers. In a cadaveric porcine spine, we evaluated the post-implantation MRI scans of three intervertebral spacers that differed in shape, material, surface qualities and implantation technique. A spacer made of human cortical bone was used as a control. The median sagittal MRI slice was divided into 12 regions of interest (ROI). No significant differences were found on 15 different MRI sequences read independently by an interobserver-validated team of specialists (P>0.05). Artifact-affected image quality was rated on a score of 0-1-2. A maximum score of 24 points (100%) was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. The carbon, titanium and cobalt-chrome spacers scored 83.3, 62.5 and 50%, respectively. Our scoring system allowed us to create an implant-related ranking of MRI scan quality in reference to the control that was independent of artifact dimensions. The carbon spacer had the lowest percentage of susceptibility artifacts. Even with turbo spin echo sequences, the susceptibility artifacts produced by the metallic spacers showed a high degree of variability. Despite optimum sequencing, implant design and material are relevant factors in MRI artifacting.

Animals↗
PubMed2006

[Improvement of tomographic reconstruction in bone SPECT].

AIM: The comparison between iterative reconstruction and filtered backprojection in the reconstruction of bone SPECT in the diagnosis of skeletal metastases. PATIENTS, METHODS: 47 consecutive patients (vertebral segments: n = 435), with suspected malignancy of the vertebral column, were examined by bone scintigraphy and MRI (maximal interval between the two procedures +/- 5 weeks). The SPECT-data were reconstructed with an iterative algorithm (ISA) and with filtered backprojection. We defined semiquantitative criteria in order to assess the quality of the tomograms. Conventional reconstruction was performed both by a Wiener-filter and a low-pass-filter. Iterative reconstruction was performed by the ISA algorithm. The clinical evaluation of the different reconstruction algorithms was performed by MRI as the gold-standard. RESULTS: Sensitivity (%): 87.3 (ISA), 86.4 (low-pass), 79.7 (Wiener); specificity (%): 95.3 (ISA), 95 (low-pass), 85.4 (Wiener). The sensitivity of iterative reconstructed SPECT and low-pass reconstructed SPECT was significantly higher (p < 0.05) compared with the sensitivity of SPECT reconstructed by the Wiener-filter. The specificity of iterative reconstruction ISA and low-pass-filter reconstructed SPECT were significantly higher compared with the SPECT data reconstructed by the Wiener-filter. ISA was significantly superior to the Wiener-SPECT relating to all criteria of quality. Iterative reconstruction was significantly superior to the low-pass-SPECT relating to 2 of 3 criteria. In addition the Wiener-SPECT was significantly inferior to the low-pass-SPECT regarding to 2 of 3 criteria. CONCLUSION: In our series the iterative algorithm ISA was the method of choice in the reconstruction of bone SPECT data. In comparison with conventional algorithms ISA offers a significantly higher quality of the tomograms and yields a high diagnostic accuracy.

Female↗
PubMed2006

Autologous chondrocyte transplantation for treating cartilage defects of the talus.

BACKGROUND: Despite its highly specialized nature, articular cartilage has a poor reparative capability. Treatment of symptomatic osteochondral defects of the talus has been especially difficult until now. METHODS: We performed autologous chondrocyte transplantation in twelve patients with a focal deep cartilage lesion of the talus. There were seven female and five male patients with a mean age of 29.7 years. The mean size of the lesion was 2.3 cm(2). All patients were studied prospectively. Evaluation was performed with use of the Hannover ankle rating score, the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, a visual analogue scale for pain, and magnetic resonance imaging. RESULTS: All patients were available for follow-up at a mean of sixty-three months. There was a significant improvement in the Hannover score, from 40.4 points preoperatively to 85.5 points at the follow-up examination, with seven excellent results, four good results, and one satisfactory result. The AOFAS mean score was 88.4 points compared with 43.5 points preoperatively. Magnetic resonance imaging showed a nearly congruent joint surface in seven patients, discrete irregularities in four, and an incongruent surface in one. The patients who had been involved in competitive sports were able to return to their full activity level. CONCLUSIONS: The promising clinical results of this study suggest that autologous chondrocyte transplantation is an effective and safe way to treat symptomatic osteochondral defects of the talus in appropriately selected patients.

Adolescent↗
PubMed2005

[Non-destructive, preclinical evaluation of root canal anatomy of human teeth with flat-panel detector volume CT (FD-VCT)].

PURPOSE: Successful endodontic diagnostics and therapy call for adequate depiction of the root canal anatomy with multimodal diagnostic imaging. The aim of the present study is to evaluate visualization of the endodont with flat-panel detector volume CT (FD-VCT). MATERIALS AND METHODS: 13 human teeth were examined with the prototype of a FD-VCT. After data acquisition and generation of volume data sets in volume rendering technology (VRT), the findings obtained were compared to conventional X-rays and cross-section preparations of the teeth. RESULTS: The anatomical structures of the endodont such as root canals, side canals and communications between different root canals as well as denticles could be detected precisely with FD-VCT. The length of curved root canals was also determined accurately. The spatial resolution of the system is around 140 microm. Only around 73 % of the main root canals detected with FD-VCT and 87 % of the roots could be visualized with conventional dental X-rays. None of the side canals, shown with FD-VCT, was detectable on conventional X-rays. In all cases the enamel and dentin of the teeth could be well delineated. No differences in image quality could be discerned between stored and freshly extracted teeth, or between primary and adult teeth. CONCLUSION: FD-VCT is an innovative diagnostic modality in preclinical and experimental use for non-destructive three-dimensional analysis of teeth. Thanks to the high isotropic spatial resolution compared with conventional X-rays, even the minutest structures, such as side canals, can be detected and evaluated. Potential applications in endodontics include diagnostics and evaluation of all steps of root canal treatment, ranging from trepanation through determination of the length of the root canal to obturation.

Adult↗
PubMed2005

Three-dimensional, non-destructive visualization of vertical root fractures using flat panel volume detector computer tomography: an ex vivo in vitro case report.

AIM: To detect and to visualize radiographically vertical root fractures in extracted teeth with a prototype of a novel, high resolution, three-dimensional flat panel volume detector computer tomograph (FD-VCT) system. SUMMARY: Five teeth with root fillings and clinical symptoms such as fistulas and isolated periodontal pockets of 8 mm or more were extracted after dental radiography indicating lateral or periapical lesions. Vertical root fractures or cracks were suspected because of the symptoms and clinical findings were evident after extraction in all cases but fracture lines were not visible on routine dental radiographs acquired before extraction. The extracted teeth were explored with a prototype of a FD-VCT. Using the FD-VCT, in all cases vertical root fractures or crack lines could be detected clearly in different views, depiction-modes and cross-sections at a spatial resolution of 140 microm. The evaluation of the fracture lines and teeth could be performed in three-dimensional views. The FD-VCT findings were confirmed by detailed inspection of the extracted teeth. KEY LEARNING POINTS: The FD-VCT is an innovative diagnostic tool for non-destructive, three-dimensional evaluation of extracted teeth in pre-clinical and experimental studies. The FD-VCT allows precise visualization and evaluation of vertical root fractures or cracks in extracted teeth. Clinical application of the system may be possible if technical modifications reduce the exposure dose: the high resolution detector systems of the FD-VCT should be combined with radiation systems that focus the radiation to the area of interest.

Humans↗
PubMed1997

Sickle cell-related pain: perceptions of medical practitioners.

Pain is the most common problem encountered by patients with sickle cell disease (SCD). We report the results of a survey sent to hematologists and emergency department (ED) physicians regarding their perceptions and practices concerning pain and its management. Hematologists and ED physicians differed considerably in their perceptions about the natural history of the pain, and about the percentage of patients who are addicted to analgesics. Fifty-three percent of the ED physicians and 23% of the hematologists thought that more than 20% of patients are addicted. These beliefs and perceptions about SCD-related pain and the prevalence of addiction must be addressed if clinical care is to be changed substantively.

Anemia, Sickle Cell↗
PubMed1984

Ibuprofen in the treatment of postoperative pain.

The site and type of operation and the age of the patient help determine the intensity of postoperative pain and the level of medication necessary for relief. Controlled clinical trials have shown that ibuprofen (Motrin) is an effective and safe analgesic for patients with mild to moderate postoperative pain. In a study of 120 patients with postoperative orthopedic pain, ibuprofen was more effective than acetaminophen-codeine and had a longer duration of action.

Acetaminophen↗
PubMed1983

Central nervous system excitatory effects of meperidine in cancer patients.

The analgesic meperidine has been reported to produce signs of central nervous system excitation in human beings. To determine the relationship between signs and symptoms of central nervous system excitation and plasma levels of meperidine and normeperidine, we studied 67 patients receiving meperidine for the relief of postoperative or chronic pain. In 48 patients, excitatory effects ranging from mild nervousness to tremors, twitches, multifocal myoclonus, and seizures were directly correlated with accumulation of normeperidine in plasma. Evidence of compromised renal function occurred in only 14 of the 48 symptomatic patients, suggesting that renal dysfunction may contribute to but is not the sole factor in the accumulation of normeperidine or its relation to adverse neurological signs. In a second study we surveyed mood alterations in 47 patients receiving meperidine and 29 receiving other narcotic analgesics for postoperative pain. The repeated administration of meperidine was associated with adverse alterations in various elements of mood (e.g., apprehension, sadness, restlessness).

Adolescent↗
PubMed1980

Relative analgesic potency of oral zomepirac and intramuscular morphine in cancer patients with postoperative pain.

A twin crossover assay of oral zomepirac and intramuscular morphine was completed in 159 cancer patients with postoperative pain. Zomepirac was a surprisingly effective oral analgesic in these patients, 100 mg orally being roughly equivalent to 16 mg intramuscular morphine. Time-effect data indicate that the peak effect for oral zomepirac may occur slightly later than that for morphine but that zomepirac is relatively rapidly effective after oral administration. Side effect occurrence was roughly in the same range for both drugs, with drowsiness, nausea, dry mouth, and feelings of weakness being observed after both drugs while sweating was observed more frequently after zomepirac. The assay further provided a demonstration of the effectiveness of the twin crossover design as a clinical assay method, providing increased sensitivity of crossover data in a patient population available for only a limited number of study treatments.

Administration, Oral↗
PubMed1979

Relative analgesic potency of intramuscular heroin and morphine in cancer patients with postoperative pain: a preliminary report.

The results of this study in postoperative patients have, thus far, revealed little that was not expected from a review of the literature. Heroin hydrochloride appears to be about two to three times more potent than morphine sulfate as an analgesic, to act more promptly and to have a slightly shorter duration of action. There is a suggestion that heroin may have a somewhat different spectrum of side effects and mood effects compared to morphine, but the effects of both drugs on mood were inversely correlated with the patients' feelings at the time of drug administration. Regardless, as a group, patients responded to both drugs with significantly improved moods. A lag time between the peak intensity of analgesic and mood effects of both heroin and morphine suggest a dissociation between these effects. Whether or not these early impressions will be reinforced as this study proceeds, and whether or not the effects of the drugs in patients with chronic pain due to advanced cancer will be any different than in these patients with postoperative pain, remains to be seen.

Affect↗
PubMed1979

Clinical analgesic assay of oral zomepirac and intramuscular morphine.

Zomepirac appears to be an unexpectedly effective oral, non-opioid analgesic. The relative potency of oral zomepirac is roughly 1/5 to 1/8 that of intramuscular morphine. Visual analogues of pain relief offer a reliable alternative to verbal categorical scales, and may provide some advantages in assays of peak drug effect, and in relatively small patient populations.

Administration, Oral↗