[Physical and technical aspects of digital mammography]

The establishment of digital mammography systems constitutes a slow process, the reason for this being the general need of particular image quality in mammography. This article provides an overview of the physical basis of digital mammography with high image quality and dose as low as reasonably achievable. The trade-off of high contrast resolution and effective quantum efficiency of the imaging system on the one hand, and the demand of high spatial resolution or very small pixel size on the other hand is discussed. The actual status of the available digital detector technology for mammography is described. The digital systems presently available are superior to conventional screen-film mammographic systems with respect to contrast resolution. An outlook on possible further developments in the field of digital mammography is presented.

[Digital full field mammography: comparison between radiographic direct magnification and digital monitor zooming]

PURPOSE

Our goal was to compare digital magnification mammograms with images zoomed from the digital contact mammogram in patients with microcalcifications.

PATIENTS AND METHODS

Fifty-five patients with 57 microcalcification clusters were evaluated with a FFDM system (Senographe 2000D, GE). In addition to a digital contact mammogram, a digital direct magnification mammogram (factor 1.8 [MAG1.8]) and an image zoomed from the contact mammogram with a magnification factor of 1.8 [ZOOM1.8] were obtained in each patient. The image quality (perfect = 5 points to inadequate = 1 point) and the characterization of microcalcifications (BI-RADS 2-5) were evaluated by 4 readers. The results were compared to histopathologic findings in 35 patients (37 lesions) and follow-up in 20 patients.

RESULTS

Histopathology revealed 16 benign and 21 malignant lesions. 20 patients had benign changes verified by long-term follow-up. Image quality of direct magnification FFDM was assessed superior (4.44 points) to zoomed images (4.14 points). Sensitivity was superior for direct magnification (97.5%) in comparison to the zoomed images (96.3%). However, specificity (MAG1.8: 34.3%, ZOOM1.8: 40%), PPV (MAG1.8: 47.5%, ZOOM1.8: 49.8%) and accuracy (MAG1.8: 58.1%, ZOOM1.8: 61.2%) were better with zooming technique. Deviation steps from best BI-RADS assessment were 0.45 for MAG1.8 and 0.44 for ZOOM1.8.

CONCLUSIONS

In patients with mammographic microcalcifications, monitor zooming of the digital contact mammogram is equivalent to direct magnification FFDM. Therefore, monitor zooming allows a reduction of the radiation exposure and an optimization of the work-flow.

[Soft copy versus hard copy findings in digital mammography]

The advantages of full field digital mammography are the excellent and reliable image quality and the reduction of radiation exposure. Image acquisition and display are decoupled in digital mammography allowing for optimization of both independently. Image displays are currently either hardcopy produced with a laser printer or softcopy using a computer monitor. Since the amount of data is high the hardware and software must meet specific technical specifications. The diagnostic accuracy of softcopy and hardcopy interpretation is comparable if a high resolution laser printer and a high quality workstation with high spatial and contrast resolution monitors are used. However, using film display the potential benefits of digital mammography in terms of manipulation of the data is lost. Additional diagnostic benefits might be gained by the combination of softcopy display and computer assisted diagnosis (CAD) and telemammography.

[Fractures of the cervical vertebrae: diagnosis with multi-slice spiral CT]

PURPOSE

It is the aim of this study to investigate the efficiency of multislice helical CT for the diagnosis of cervical spine fractures. The advantages of this technique are demonstrated by case reports.

MATERIAL AND METHODS

The entire cervical spine or selected vertebral bodies of 66 patients with cervical spine fractures known from preceding plain films were scanned with a multislice helical CT. The CT-scans were obtained with a slice thickness of 1.25 mm and with two different pitches (0.75 or 1.5) and table speeds (3.75 or 7.5 mm/rot.). Additionally, sagittal and coronal reformations were performed.

RESULTS

The mean scan-time for the cervical spine was 13 seconds. High quality sagittal and coronal reformations were obtained from axial images within a few minutes. Fractures of the dens (n = 17) and of the vertebral body of C3-C7 (n = 12) occurred predominantly.

CONCLUSION

Multislice helical CT is an effective tool to diagnose fractures of the cervical spine rapidly and exactly.

[Intramural hematomas of the aorta]

Intramural hematomas (IMH) are regarded as a hemorrhage into the aortic wall. In general a traumatic form can de differentiated from a spontaneous non-traumatic. There is a predisposition of IMH with arterial hypertension and mesoectodermal dysplastic syndromes. The diagnosis is established with the clinical presentation in combination with the findings of different imaging modalities. Acute and subacute discomfort associated with a tendency of collaps are considered as typical presenting complaints. A semicircular or concentric thickening of the aortic wall with the absence of blood flow or a dissection membrane are typical findings in transesophageal echocardiography, computed tomography and magnetic resonance tomography. From a differential diagnostic point of view a distinction from atherosclerotic wall changes, intraluminal thrombi and inflammatory aortic diseases is essential. The IMH is considered as an early presentation of aortic dissection, put into and treated according to the Stanford classification. In the course of natural history an IMH can disappear, rupture or progress into a classic aortic dissection.

[Diagnosis of lung embolism and underlying venous thrombosis in multi-slice spiral CT]

AIM

To determine the value of multi-slice CT for the diagnosis of acute pulmonary embolism and an underlying venous thrombosis.

METHODS

70 patients with clinically suspected acute pulmonary embolism were examined. Using multi-slice CT a combined examination of the pulmonary arteries and the veins of the lower limb, pelvis and abdomen was performed. Only one single bolus of 150 ml iopromid 300 was injected into a cubital vein with a flow of 4 ml/s. First, the pulmonary arteries were scanned with a slice thickness of 2.5 mm and a pitch of 1.5. On arrival of the contrast medium at the popliteal veins, indicated by bolus trakking, the veins of the lower limbs up to the end of the inferior vena cava were imaged using a slice thickness of 3.75 mm and a pitch of 1.5. The results could be compared with a ventilation-perfusion scan in 48 cases, with a Doppler ultrasound examination in 46 cases, and with a venography in 10 cases. Furthermore, the image quality of all arterial and venous regions was subjectively assessed.

RESULTS

In all patients who underwent multi-slice CT the pulmonary arteries as well as the veins of the lower half of the body could be recorded completely. Regarding the pulmonary arteries the image quality showed excellent results for the central and segmental arteries. The region up to the 3rd division in subsegmental branches could be sufficiently judged. More peripherally, a diagnostic assessment was not possible. The image quality of the veins was excellent in all sections, except the calf, where a reliable diagnosis could not be made. The comparison with the other techniques confirmed the superiority of multi-slice CT concerning the central and segmental pulmonary arteries and the veins from the popliteal vein to the inferior vena cava. In contrast, peripheral pulmonary emboli can be detected more certainly in ventilation/perfusion scans. The veins of the calf can be evaluated more reliably with venography.

CONCLUSION

Multi-slice CT proved to be an outstanding tool in the diagnosis of acute pulmonary embolism. The clinically suspected disease and a causing venous thrombosis can be detected in a fast and reliable way. At present, multi-slice CT is not suitable for the recognition of peripheral emboli. However, expected technical developments hold promise for future improvements.

[Value and significance of digital full-field mammography within the scope of mammography screening]

To evaluate the digital technique for screening mammography various experimental studies and clinical examinations were performed by using direct full-field digital mammography (FFDM). The findings concerning the detectability and characterization of microcalcifications and soft tissue masses as well as the radiation exposure were compared to the state-of-the-art conventional screen-film mammography (SFM). The results of these studies revealed a high performance of the digital images, which are at least equivalent to the conventional images, whereas digital spot views were significantly superior to conventional ones particularly in the detection of microcalcifications. This was especially true, when the potential of post-processing was used. In addition, the sensitivity of FFDM should be increased, if computer-aided-diagnosis (CAD) is available. Furthermore, the patient radiation dose can be significantly reduced. Additional advantages are quick and easy handling, efficient data transfer and digital archiving. Thus, FFDM will become an important tool in screening mammography.

[Factitious wounds in plastic surgery]

Self-inflicted disorders of wound healing were diagnosed in two women (aged 24 and 25 years) after long years of history. A detailed medical history and the characteristic course helped to confirm the diagnosis. The artificial wounds were an expression of a severe psychic disturbance in both young women. Operative therapy was able to restore the local findings, the basic psychological disorder required a long-term psychotherapeutic treatment to prevent irreversible, partially iatrogenic co-induced somatic mutilations, due to an exceptionally high recurrence rate.

The relationship of magnetic source imaging to ictal electrocorticography in a neuronavigational workspace

Magnetic source imaging (MSI) registers magnetoencephalographic (MEG) activity to a three-dimensional MRI volume. State-of-the-art MSI allows concurrent whole head coverage, but is practically restricted to interictal recording. However, the purpose of the presurgical evaluation of epileptic patients, in which MSI is playing an increasing role, is the elucidation of the ictal epileptogenic focus. The manner in which interictal MSI activity relates to the ictal focus has not yet been adequately examined. To facilitate this analysis, we are developing techniques to precisely coregister MSI to the ictal onset zone as defined by extraoperative intracranial grid/strip monitoring. The neuronavigational workspace is a convenient area in which to precisely coregister these (and other) imaging and physiological data sets.

[Intra-individual comparison of alpha- and beta-TCP ceramics in an animal experiment]

In the quest for bioinert adaptable alloplastic materials, TCP ceramics have gained a new application in craniofacial bone substitutes. Therefore, a histomorphological, intraindividual, comparative study was conducted on seven adult Goettingen miniature pigs (GMP) to analyze the difference of the degradation and remodelling processes of alpha-TCP and beta-TCP in critical size defects of the proximal tibiae. In addition, primary insertion of dental implants followed to study osseous integration. The critical size defects, which were created in the proximal tibiae in GMPs, were filled on the left side with beta-TCP and on the right side with alpha-TCP. Two GMPs were used as control group. After 4-68 weeks of investigation, the GMPs were sacrificed by narcosis. The histological investigation showed that these ceramics have an osteoconductive effect. It was noted that ossification proceeds centripetally. It could be demonstrated that the degradation of the materials follows a hydrolytical process and that the intratrabecular integrated ceramic remnants follow a dynamic remodelling process. Within 68 weeks after implantation, 90% of the TCP granulae were degraded. Macrophages were found in the marrow space, containing microparticles of TCP, especially after alpha-TCP implantation. In conclusion, defined degradation of these ceramics allows early functional bone regeneration with an additional undisturbed biofunctional unisotrop orientation of new trabeculae. Furthermore, dental implants should be inserted 5-6 months after TCP implantation.

[Full-field digital mammography: a phantom study for detection of microcalcification]

OBJECTIVES

The study compares direct full-field digital mammography (FFDM) to the state-of-the-art conventional screen-film mammography (SFM) concerning the detectability of simulated microcalcifications.

MATERIALS AND METHODS

The investigations were performed with a FFDM system (Senographe 2000D, GEMS) and a SFM system (Senographe DMR, GEMS, Fuji UM MA film with Fuji UM MAMMO FINE screen). An anthropomorphic breast phantom with superimposed microcalcifications (50-200 microns) was used to evaluate the detectability of microcalcifications with a confidence level ranging from 1 to 5. Contact mammograms and magnification spot views (m = 1.8) of the FFDM and SFM systems were compared. A receiver operating characteristic (ROC) analysis was performed by three well-experienced readers.

RESULTS

The ROC analysis revealed a higher performance of the digital images compared to the conventional screen-film mammograms. The area under the ROC-curve (Az) in the digital contact mammograms was 0.68 versus 0.63 in the conventional technique. The results were not significantly different. In digital spot views, Az was 0.79 versus 0.70 in the conventional spot views.

CONCLUSIONS

The results suggest that FFDM is at least equivalent or--as far as spot views are concerned--may be superior to conventional SFM in the detection of microcalcifications.

Flap perfusion after free musculocutaneous tissue transfer: the impact of postoperative complications

In a previous study, the authors found persistence of pedicle blood flow up to 10 years after uncomplicated free latissimus dorsi transfer. In this study, the impact of postoperative complications (hematoma, thrombosis, infection) and successful surgical revision was tested. Since 1982, more than 1200 free tissue transfers have been performed at the authors' institution (Hannover Medical School). Of these, the authors selected two groups of 30 patients each who had received a free latissimus dorsi transfer to the lower leg without microsurgical nerve coaptation for wound coverage. All patients included in this study were carefully selected for clinical homogeneity, with one difference: group I comprised patients who had no postoperative complications after free latissimus dorsi transfer. Group II included only patients with major postoperative complications after the procedure. All flaps in group II survived after successful surgical revision. The arteries, which nourished the lower leg, were visualized and documented by means of a duplex scanner in both groups. Three different time intervals were chosen for measurements of blood flow: 4 to 6 months (groups I.I and II.I), 4 to 6 years (groups I.II and II.II), and 8 to 10 years (groups I.III and II.III). Quantitative measurements of local flap perfusion in milliliters per minute per 100 g tissue were performed by means of the hydrogen clearance technique. In each patient, a total of nine measurements was performed in three phases: phase A, before closing the vascular pedicle by manual compression (n = 3); phase B, with a closed pedicle (n = 3); and phase C, after releasing the vascular pedicle from manual compression (n = 3). Each measurement took approximately 10 minutes. One hundred percent closure of each pedicle in phase B was confirmed by the duplex scanner. Furthermore, all patients were monitored both clinically and by means of the hydrogen clearance technique during phase B for adequate blood supply to the lower leg. Lower leg perfusion showed no statistical differences for phases A, B, and C in all groups of patients. In group I, no statistical differences in local flap perfusion were encountered for phases A and C. In phase B, however, a statistically significant (p < 0.01) complete extinction of local flap perfusion was registered in all patients of group I at the site of the flap's skin paddle. In group II, however, persistent flap perfusion was registered during phase B in up to 50 percent of cases in one subgroup (II.III). No statistically significant alterations of local blood flow were registered in the surrounding tissue of group II during phases A, B, and C. Patients with thrombosis of the venous anastomosis (n = 7) seemed to have the highest incidence of loss of autonomous blood supply through the vascular pedicle (5 out of 11 cases). No inconstant results were found during the repetitive measurements (n = 3) for each patient in each phase. After uncomplicated free tissue transfer, the flap's intact vascular pedicle seems to play an important role in permanent flap survival up to 10 years after the procedure. Postoperative complications after free tissue transfer with successful surgical revision, especially venous thrombosis of the vascular anastomosis, may lead to loss of vascular flap autonomy over time.

[Does tissue perfusion after free microvascular tissue transplantation remain autonomous?]

In a retrospective study, including 60 patients, after free latissimus dorsi transplantation (FLDT) to the lower leg, we found persistent pedicle blood flow up to ten years postoperatively. After uncomplicated FLDT, the pedicle supported the flap in all cases. After complicated FLDT (hematoma, thrombosis, infection) only 50% of all flaps after ten years were perfused by the vascular pedicle.

Auxin-dependent cell wall depositions in the epidermal periplasmic space of graviresponding nodes of Tradescantia fluminensis

Differential growth of the nodal regions of graviresponding Tradescantia fluminensis (Wandering Jew) was analysed with special respect to the extension-restricting epidermal cells of the opposite growing and growth-inhibited organ flanks. Gravicurvature of horizontally gravistimulated isolated nodes depends on auxin (indolyl-3-acetic acid, IAA) and shows a node-specific profile in which the third node below the tip showed the greatest response. Exogenously supplied gibberellic acid induced no gravitropic growth. Vertically oriented isolated nodes supplied with exogenous IAA showed, on an electron microscopical level, conspicuous membrane invaginations with adjacent wall depositions restricted to the outer tangential epidermal cell walls. Their number was more than doubled by exogenously supplied Ca2+, which inhibited IAA-induced growth. No such changes could be detected in water-incubated segments or inner tissues of IAA-supplied segments. Gravistimulated differential growth of nodes of intact shoots and of nodal segments was characterized by changes similar to the ones induced by exogenous IAA, with greatly increased numbers of wall depositions within the epidermal cells of the growth-inhibited upper organ flank. Similar to the gravistimulated wall depositions, an asymmetric distribution pattern of Ca2+ was detected in the epidermal cell walls employing x-ray energy spectrum analysis (EDX). The results indicate that growth of nodes of Tradescantia fluminensis is regulated via IAA-induced secretion and subsequent infiltration of wall components enabling wall extension. The data support the hypothesis that temporary differential growth during gravicurvature of Tradescantia fluminensis is mediated by the antagonistic effect of Ca(2+)-ions on the infiltration of IAA-induced wall-loosening components into the outer, extension-restricting epidermal walls thereby inhibiting growth.

[Computer-assisted visualization of digital mammography images]

PURPOSE

In a clinical study, the feasibility of using a mammography workstation for the display and interpretation of digital mammography images was evaluated and the results were compared with the corresponding laser film hard copies.

MATERIALS AND METHODS

Digital phosphorous plate radiographs of the entire breast were obtained in 30 patients using a direct magnification mammography system. The images were displayed for interpretation on the computer monitor of a dedicated mammography workstation and also presented as laser film hard copies on a film view box for comparison. The images were evaluated with respect to the image handling, the image quality and the visualization of relevant structures by 3 readers.

RESULTS

Handling and contrast of the monitor displayed images were found to be superior compared with the film hard copies. Image noise was found in some cases but did not compromise the interpretation of the monitor images. The visualization of relevant structures was equal with both modalities. Altogether, image interpretation with the mammography workstation was considered to be easy, quick and confident.

CONCLUSIONS

Computer-assisted visualization and interpretation of digital mammography images using a dedicated workstation can be performed with sufficiently high diagnostic accuracy.

[Slice sensitivity profile and image pixel noise of multi-slice spiral CT in comparison with single slice spiral CT]

PURPOSE

Presentation and evaluation of slice sensitivity profile and pixel noise of multi-slice CT in comparison to single-slice CT.

METHODS

Slice sensitivity profiles and pixel noise of a multi-slice CT equipped with a 2D matrix detector array and of a single-slice CT were evaluated in phantom studies.

RESULTS

For the single-slice CT the width of the slice sensitivity profiles increased with increasing pitch. In spite of a much higher table speed the slice sensitivity profiles of multi-slice CT were narrower and did not increase with higher pitch. Noise in single-slice CT was independent of pitch. For multi-slice CT noise increased with higher pitch and for the higher pitch decreased slightly with higher detector row collimation.

CONCLUSIONS

Multi-slice CT provides superior z-resolution and higher volume coverage speed. These qualities fulfill one of the prerequisites for improvement of 3D postprocessing.

Magnetoencephalographic patterns of epileptiform activity in children with regressive autism spectrum disorders

BACKGROUND

One-third of children diagnosed with autism spectrum disorders (ASDs) are reported to have had normal early development followed by an autistic regression between the ages of 2 and 3 years. This clinical profile partly parallels that seen in Landau-Kleffner syndrome (LKS), an acquired language disorder (aphasia) believed to be caused by epileptiform activity. Given the additional observation that one-third of autistic children experience one or more seizures by adolescence, epileptiform activity may play a causal role in some cases of autism.

OBJECTIVE

To compare and contrast patterns of epileptiform activity in children with autistic regressions versus classic LKS to determine if there is neurobiological overlap between these conditions. It was hypothesized that many children with regressive ASDs would show epileptiform activity in a multifocal pattern that includes the same brain regions implicated in LKS.

DESIGN

Magnetoencephalography (MEG), a noninvasive method for identifying zones of abnormal brain electrophysiology, was used to evaluate patterns of epileptiform activity during stage III sleep in 6 children with classic LKS and 50 children with regressive ASDs with onset between 20 and 36 months of age (16 with autism and 34 with pervasive developmental disorder-not otherwise specified). Whereas 5 of the 6 children with LKS had been previously diagnosed with complex-partial seizures, a clinical seizure disorder had been diagnosed for only 15 of the 50 ASD children. However, all the children in this study had been reported to occasionally demonstrate unusual behaviors (eg, rapid blinking, holding of the hands to the ears, unprovoked crying episodes, and/or brief staring spells) which, if exhibited by a normal child, might be interpreted as indicative of a subclinical epileptiform condition. MEG data were compared with simultaneously recorded electroencephalography (EEG) data, and with data from previous 1-hour and/or 24-hour clinical EEG, when available. Multiple-dipole, spatiotemporal modeling was used to identify sites of origin and propagation for epileptiform transients.

RESULTS

The MEG of all children with LKS showed primary or secondary epileptiform involvement of the left intra/perisylvian region, with all but 1 child showing additional involvement of the right sylvian region. In all cases of LKS, independent epileptiform activity beyond the sylvian region was absent, although propagation of activity to frontal or parietal regions was seen occasionally. MEG identified epileptiform activity in 41 of the 50 (82%) children with ASDs. In contrast, simultaneous EEG revealed epileptiform activity in only 68%. When epileptiform activity was present in the ASDs, the same intra/perisylvian regions seen to be epileptiform in LKS were active in 85% of the cases. Whereas primary activity outside of the sylvian regions was not seen for any of the children with LKS, 75% of the ASD children with epileptiform activity demonstrated additional nonsylvian zones of independent epileptiform activity. Despite the multifocal nature of the epileptiform activity in the ASDs, neurosurgical intervention aimed at control has lead to a reduction of autistic features and improvement in language skills in 12 of 18 cases.

CONCLUSIONS

This study demonstrates that there is a subset of children with ASDs who demonstrate clinically relevant epileptiform activity during slow-wave sleep, and that this activity may be present even in the absence of a clinical seizure disorder. MEG showed significantly greater sensitivity to this epileptiform activity than simultaneous EEG, 1-hour clinical EEG, and 24-hour clinical EEG. The multifocal epileptiform pattern identified by MEG in the ASDs typically includes the same perisylvian brain regions identified as abnormal in LKS. When epileptiform activity is present in the ASDs, therapeutic strategies (antiepileptic drugs, steroids, and even neurosurgery) aimed at its control can lead to a significa

Psychoendocrine sequelae of chronic testosterone deficiency

The precise role of testosterone in regulating mood, especially in alleviating depression, remains unclear although converging evidence indicates that androgens may exert antidepressant action. A model that may potentially assist in the clarification of androgen-mediated effects on mood is the study of cryptorchid men who may grow up with varying degrees of testosterone deficiency depending on the time in their life when cryptorchism is corrected. In this report, we describe a rare case of bilateral cryptorchism that did not come to the attention of the physician to implement effective substitution with testosterone until much later in adult life. The patient developed severe and suicidal depression which responded solely to testosterone. In addition, the patient experienced a delayed but accelerated puberty without any adverse events. These observations, although based on a single case, provide strong evidence that testosterone may exert powerful antidepressant action in the absence of concomitant antidepressant agents.

[Direct digital magnification mammography with a large-surface detector made of amorphous silicon]

PURPOSE

To investigate the image quality of a new direct digital mammography system using a large-area amorphous silicon X-ray detector in a phantom study.

MATERIALS AND METHODS

The contrast-detail resolution as a function of the tube voltages, the magnification factors and the mean glandular doses were investigated using dedicated test objects.

RESULTS

The contrast-detail resolution was significantly improved in comparison with conventional screen-film mammography. Usually, the doses necessary to obtain these high-quality survey mammograms were smaller.

CONCLUSIONS

By combining the direct magnification technique and a digital flat panel detector the limited spatial resolution of such image receptors can be overcome. With this direct digital mammography technique, a digital image was directly captured without an intermediate step of optical or mechanical scan.

[Does tissue perfusion after free microvascular tissue transplantation stay autonomous?]

In a prospective study including 60 patients after free latissimus dorsi transfer (FLDT) to the lower leg, we found persistence of pedicle blood flow up to 10 years postoperatively. After uncomplicated FLDT the pedicle supported the flap in all cases, whereas after complicated FLDT (hematoma, thrombosis, infection) we found only 50% of all flaps autonomously perfused by the vascular pedicle.

[Dental CT: image quality and radiation exposure in relation to scan parameters]

PURPOSE

To develop a scan protocol for dental-CT which guarantees good image quality at the lowest possible radiation dose.

METHODS

In an experimental investigation Dental-CT (HSA, GE, Milwaukee, USA) of the mandible of two human skeletons positioned in a water tank were performed in order to define the most advantageous scan protocol. Tube currents ranged from 40 to 200 mA and the scan technique was modified (axial mode or helical mode with pitches of 1 to 3 and corresponding increments of 0.4 to 1.0 mm). 39 patients underwent a dental-CT with decreased current (80 mA) in the helical scan mode (pitch 2, slice thickness 1 mm). Dose measurements were performed for two different scan protocols (A: axial, 130 mAs, B: helical, 80 mA, pitch 2).

RESULTS

The preliminary investigations of image quality showed only a minor effect of the applied current. For the helical scan mode, pitches of more than 2 impaired image quality. A low increment had no advantages. There were no disadvantages in clinical practice using protocol B with decreased tube current. Absorbed radiation dose of dental CT performed with protocol B was decreased to one third in comparison to protocol A.

CONCLUSIONS

A scan protocol with a low tube current (e.g., 80 mA, for a rotation time of 1 s) and a helical scan mode (e.g., for a slice thickness of 1 mm with a pitch of 2 and an increment of 1 mm) is recommended for performing dental-CT.

[Instability of spinal fractures--therapeutic relevance of different classifications]

PURPOSE

To investigate if the assessment of spinal fracture stability according to the Magerl classification permits a better therapy decision than using the Denis 3-column model.

MATERIAL AND METHODS

The X-ray and CT images of 99 consecutive patients treated for thoracolumbar spine fractures were analysed and the fractures were classified according to the above mentioned classifications. Using the 3-column model, the involvement of two or more columns was considered as unstable, whereas the fracture types A3.2, A3.3, B and C of the Magerl classification were defined as unstable. The stability evaluation was compared with the therapy decision and outcome.

RESULTS

According to the 3-column model, 23 of 53 fractures which were classified as unstable were operated. Only five of the 30 conservatively treated unstable fractures showed a reduced healing process. The 46 stable fractures were treated conservatively with good results. Using the Magerl classification, 21 of the 28 unstable fractures were operated and 4 of the remaining 7 cases showed a reduced healing process. Of the 71 stable fractures only 2 were operated and in one patient minimal neurological symptoms occurred.

CONCLUSION

The Magerl classification enables a more exact definition of stable and unstable spinal fractures.