Comparison of anode/filter combinations in digital mammography with respect to the average glandular dose.

PURPOSE: To investigate the average glandular dose (AGD) applied for clinical digital mammograms acquired with the anode/filter combinations molybdenum/molybdenum (Mo/Mo), molybdenum/rhodium (Mo/Rh), and tungsten/rhodium (W/Rh). MATERIALS AND METHODS: Using the method of Dance, the AGD was evaluated from the exposure data of 4867 digital mammograms at two sites equipped with a full-field digital mammography (FFDM) system based on an amorphous selenium detector. 1793 images were acquired and analyzed with Mo/Mo, 643 with Mo/Rh, and 2431 with W/Rh. RESULTS: In the Mo/Mo cases the mean compressed breast thickness was 46 +/- 10 mm with an average AGD of 2.29 +/- 1.31 mGy. For the Mo/Rh cases with a mean compressed thickness of 64 +/- 9 mm, we obtained 2.76 +/- 1.31 mGy. The W/Rh cases with a mean compressed thickness of 52 +/- 13 mm resulted in 1.26 +/- 0.44 mGy. The image quality was assessed as normal and adequate for diagnostic purposes in all cases. CONCLUSION: Applying a W/Rh beam quality permits the reduction of the patient dose by approximately 50 % when using an FFDM system based on amorphous selenium. The dose reduction becomes larger as the breast thickness increases. The results are in agreement with simulations and phantom studies known from the literature.

An electromechanical gait trainer for restoration of gait in hemiparetic stroke patients: preliminary results.

Modern concepts of gait rehabilitation after stroke favor a task-specific repetitive approach. In practice, the required physical effort of the therapists limits the realization of this approach. Therefore, a mechanized gait trainer enabling nonambulatory patients to have the repetitive practice of a gait-like movement without overstraining therapists was constructed. This preliminary study investigated whether an additional 4-week daily therapy on the gait trainer could improve gait ability in 14 chronic wheelchair-bound hemiparetic subjects. The 4 weeks of physiotherapy and gait-trainer therapy resulted in a relevant improvement of gait ability in all subjects. Velocity, cadence, and stride length improved significantly (p < 0.01). The kinesiologic electromyogram of selected lower-limb muscles revealed a more physiologic pattern. The confounding influence of spontaneous recovery, the lack of a control group, and the double amount of therapy limit the clinical relevance of this study. Nevertheless, the gait trainer seems feasible as an adjunctive tool in gait rehabilitation after stroke; further studies are needed.

Gait with and without forearm crutches in patients with total hip arthroplasty.

There is considerable variation between centres in the use of forearm crutches in the rehabilitation of patients with total hip arthroplasty who are capable of full weight bearing. This study aimed to compare the gait of patients with total hip arthroplasty walking with and without crutches. The gait analysis in 19 patients included the assessment of kinematics, kinetics and the kinesiological electromyographic activity of lower limb and trunk muscles. With the forearm crutches patients walked with a reduced cadence, a longer stride length and more symmetrically (P < 0.05). The activity of the gluteus medius, vastus medialis and lateralis, and erector spinae muscles of the affected and of the vastus medialis muscle of the unaffected side decreased significantly (P < 0.05). Furthermore, seven subjects displayed an abnormal activation pattern of the affected hip abductor when walking with forearm crutches, characterized by a second burst during swing (n = 5) or a tonic pattern (n = 2). It is concluded that the use of forearm crutches resulted in a symmetrical gait pattern. The reduced activity of relevant pelvi-trochanteric muscles and the disturbed activation pattern of the affected hip abductor when walking with crutches might indicate that patients should walk unaided as soon as possible to provide a more efficient muscular training under dynamic conditions.

A mechanized gait trainer for restoring gait in nonambulatory subjects.

OBJECTIVE: To construct an advanced mechanized gait trainer to enable patients the repetitive practice of a gaitlike movement without overstraining therapists. DEVICE: Prototype gait trainer that simulates the phases of gait (by generating a ratio of 40% to 60% between swing and stance phases), supports the subjects according to their ability (lifts the foot during swing phase), and controls the center of mass in the vertical and horizontal directions. PATIENTS: Two nonambulatory, hemiparetic patients who regained their walking ability after 4 weeks of daily training on the gait trainer, a 55-year-old woman and a 62-year-old man, both of whom had a first-time ischemic stroke. INTERVENTION: Four weeks of training, five times a week, each session 20 minutes long. MAIN OUTCOME MEASURES: Functional ambulation category (FAC, levels 0-5) to assess gait ability and ground level walking velocity. Rivermead motor assessment score (RMAS, 0-13) to assess gross motor function. RESULTS: Patient 1: At the end of treatment, she was able to walk independently on level ground with use of a walking stick. Her walking velocity had improved from .29m/sec to .59m/sec. Her RMAS score increased from 4 to 10, meaning she could walk at least 40 meters outside, pick up objects from floor, and climb stairs independently. Patient 2: At end of 4-week training, he could walk independently on even surfaces (FAC level 4), using an ankle-foot orthosis and a walking stick. His walking velocity improved from .14m/sec to .63m/sec. His RMAS increased from 3 to 10. CONCLUSION: The gait trainer enabled severely affected patients the repetitive practice of a gaitlike movement. Future studies may elucidate its value in gait rehabilitation of nonambulatory subjects.

A mechanized gait trainer for restoration of gait.

The newly developed gait trainer allows wheel-chair-bound subjects the repetitive practice of a gait-like movement without overstressing therapists. The device simulates the phases of gait, supports the subjects according to their abilities, and controls the center of mass (CoM) in the vertical and horizontal directions. The patterns of sagittal lower limb joint kinematics and of muscle activation for a normal subject were similar when using the mechanized trainer and when walking on a treadmill. A non-ambulatory hemiparetic subject required little help from one therapist on the gait trainer, while two therapists were required to support treadmill walking. Gait movements on the trainer were highly symmetrical, impact free, and less spastic. The vertical displacement of the CoM was bi-phasic instead of mono-phasic during each gait cycle on the new device. Two cases of non-ambulatory patients, who regained their walking ability after 4 weeks of daily training on the gait trainer, are reported.

Development of an advanced mechanised gait trainer, controlling movement of the centre of mass, for restoring gait in non-ambulant subjects.

The study aimed at further development of a mechanised gait trainer which would allow non-ambulant people to practice a gait-like motion repeatedly. To simulate normal gait, discrete stance and swing phases, lasting 60% and 40% of the gait cycle respectively, and the control of the movement of the centre of mass were required. A complex gear system provided the gait-like movement of two foot plates with a ratio of 60% to 40% between the stance and swing phases. A controlled propulsion system adjusted its output according to patient's efforts. Two eccenters on the central gear controlled phase-adjusted the vertical and horizontal position of the centre of mass. The patterns of sagittal lower limb joint kinematics and of muscle activation of a normal subject were similar when using the mechanised trainer and when walking on a treadmill. A non-ambulatory hemiparetic subject required little help from one therapist on the gait trainer, while two therapists supported treadmill walking. Gait movements on the trainer were highly symmetrical, impact-free, and less spastic. The weight-bearing muscles were activated in a similar fashion during both conditions. The vertical displacement of the centre of mass was bi-instead of mono-phasic during each gait cycle on the new device. In conclusion, the gait trainer allowed wheelchair-bound subjects the repetitive practice of a gait-like movement without overstraining therapists.

Gait pattern of severely disabled hemiparetic subjects on a new controlled gait trainer as compared to assisted treadmill walking with partial body weight support.

OBJECTIVES: To investigate to what extent and with how much therapeutic effort nonambulatory stroke patients could train a gait-like movement on a newly developed, machine-supported gait trainer. DESIGN: Open study comparing the movement on the gait trainer with assisted walking on the treadmill. SETTING: Motion analysis laboratory of a rehabilitation centre. SUBJECTS: Fourteen chronic, nonambulatory hemiparetic patients. INTERVENTION: Complex gait analysis while training on the gait trainer and while walking on the treadmill. MAIN OUTCOME MEASURES: Gait kinematics, kinesiological EMG of several lower limb muscles and the required assistance. RESULTS: Patients could train a gait-like movement on the gait trainer, characterized kinematically by a perfect symmetry, larger hip extension during stance, less knee flexion and less ankle plantar flexion during swing as compared to treadmill walking (p <0.01). The pattern and amount of activation of relevant weight-bearing muscles was comparable with an even larger activation of the M. biceps femoris on the gait trainer (p <0.01). The tibialis anterior muscle of the nonaffected side, however, was less activated during swing (p <0.01). Two therapists assisted walking on the treadmill while only one therapist was necessary to help with weight shifting on the new device. CONCLUSION: The newly developed gait trainer offered severely disabled hemiparetic subjects the possibility of training a gait-like, highly symmetrical movement with a favourable facilitation of relevant anti-gravity muscles. At the same time, the effort required of the therapists was reduced.

Treadmill walking with partial body weight support versus floor walking in hemiparetic subjects.

OBJECTIVE: To compare the gait of hemiparetic subjects walking on a treadmill with various body weight supports and walking on the floor. DESIGN: Hemiparetic subjects walked on a treadmill, secured in a harness, with no body weight support and with 15% and 30% body weight relief, and walked on a floor. SETTING: Kinematic laboratory of a department of rehabilitation. SUBJECTS: Eighteen hemiparetic stroke patients. MAIN OUTCOME MEASURES: Gait cycle parameters and kinesiologic electromyogram of six muscles of the affected side and of two muscles of the nonaffected side. RESULTS: On the treadmill, patients walked more slowly because of a reduced cadence, with a longer single stance period of the paretic limb, more symmetrically, and with a larger hip extension (multivariate profile analysis, p<.05). The mean functional activities of the gastrocnemius muscle and of the first crest of the erector spinae of the paretic side were smaller on the treadmill (univariate test, p<.05). Further, the premature activity of the gastrocnemius muscle, indicating spasticity, was less on the treadmill (univariate test, p<.05); correspondingly the qualitative muscle pattern analysis revealed less co-contraction between the gastrocnemius and tibialis anterior muscles in 11 of the 18 subjects. CONCLUSIONS: Treadmill training with partial body weight support in hemiparetic subjects allows them to practice a favorable gait characterized by a greater stimulus for balance training because of the prolonged single stance period of the affected limb, a higher symmetry, less plantar flexor spasticity, and a more regular activation pattern of the shank muscles as compared with floor walking.

[Development of a gait trainer with regulated servo-drive for rehabilitation of locomotor disabled patients]. / Entwicklung eines Gangtrainers mit geregeltem Servoantrieb zur Rehabilitation gehunfähiger Patienten.

The aim of the present study was to develop a new gait trainer for the rehabilitation of non-ambulatory patients. For the simulation of the gait phase, we used a commercially available fitness trainer (Fast Track) with two foot plates moving in an alternating fashion and connected to a servo-controlled propulsion system providing the necessary support for the movement depending on the patient's impairment level. To compensate deficient equilibrium reflexes, the patient was suspended in a harness capable of supporting some of his/her weight. Video analysis of gait and the kinesiological EMG were used to assess the pattern of movement and the corresponding muscle activity, which were then evaluated in healthy subjects, spinal cord injured and stroke patients and compared with walking on the flat or on a treadmill. Walking on the gait trainer was characterised by a symmetrical, sinusoidal movement of lower amplitude than in normal gait. The EMG showed a low activity of the tibialis anterior muscle, while the antigravity muscles were clearly activated by the gait trainer during the stance phase. In summary, the new gait trainer generates a symmetrical gait-like movement, promoting weight acceptance in the stance phase, which is important for the restoration of walking ability.

[Results of CT-guided periradicular pain therapy]. / Ergebnisse der CT-gesteuerten periradikulären Schmerztherapie.

PURPOSE: The effectiveness of CT-guided periradicular pain therapy was studied. MATERIAL AND METHOD: 55 patients with lumbar and/or radicular pain were treated by periradicular injections of 40 ml triamcinolon, in some cases combined with injection of the facets of the lumbar vertebrae. 36 patients had chronic symptoms; in 7, these were acute, and 12 patients complained of renewed disc symptoms following previous disc surgery. Approximately 4 months after the conclusion of treatment, the patients were requested to complete a questionnaire giving information on the course and after-effects of treatment. The questionnaire was repeated after 5 months. RESULTS: 55% of patients were free of symptoms or had had some improvement at the time of the questionnaire; 30% reported temporary improvement, and in 15% there was no change compared with the pre-treatment symptoms. At the time of the second questionnaire, the proportion of patients who had derived benefit from the treatment was somewhat lower, 49% reported that they were pain-free or improved, while temporary improvement was reported by 36% of patients. CONCLUSION: CT-guided periradicular pain therapy is a valuable procedure in patients in whom conservative measures prove ineffective, and when surgery is not indicated. However, only about half the treated patients maintain permanent improvement.

[Pachygyria and laminar heterotopic tissue. A rare case of unique expression of a neuronal migration disorder in twins]. / Pachygyrie und laminare Heterotopie. Seltener Fall einer unterschiedlich ausgeprägten neuronalen Migrationsstörung bei Zwillingen.

We report of 16 year old twinsisters with a neuronal migration disorder, twin I with mental retardation and focal epileptic seizures on MRI showed general pachygyria, laminar subcortical heterotopia and mildly dilated lateral ventricles, whereas twin II whose first symptom was a cerebral seizure only showed a focal pachygyria and laminar subcortical heterotopia; the location of pachygyria corresponded to the epileptogenic focus. The morphological expression seems to correspond with the severeness of the clinical features. Genetic as well as exogenic factors must be assumed to be causative for the migration anomalies.

[Migration disorders of the brain--an evaluation of computed tomographic and magnetic resonance tomographic studies]. / Migrationsstörungen des Gehirns--eine Auswertung computertomographischer und kernspintomographischer Untersuchungen.

Twenty-eight patients with abnormalities of migration were examined with CT and MRI. Thirteen patients had heterotopia, ten patients had agyria/pachygyria, two with unilateral schizencephaly and three with hemimegalencephaly. MRI proved markedly superior because of its wider contrast range and its ability to obtain various imaging planes. The various conditions are described in detail.

[Intracranial calcification--how much more information can be obtained by MR than CT?]. / Intrakranielle Verkalkungen--welche Mehrinformation bietet das MR gegenüber dem CT?

Thirty-four patients known to have intracerebral calcification that had been demonstrated by CT, were also examined by MR to determine which modality would provide more information concerning the underlying pathology. There were seven patients with intra- or extracerebral intracranial calcification without any known cause, seven cavernous haemangiomas, six meningiomas, five oligodendrogliomas, one astrocytoma, one optic nerve glioma, one plexus papilloma, one pinealoma, one histologically unclassified tumour, one healed tuberculous meningitis, one old haematoma, one tuberous sclerosis and one case of basal ganglia calcification due to hypoxia. In 16 cases the two methods were of equal value, in four cases CT was more valuable than MR, but in 14 cases MR provided more information than CT. In cases of tumour calcification, MR was frequently more valuable than CT in demonstrating the tumour and its extent. It was also better in diagnosing vascular malformations and old bleedings. MR provided more information in tuberous sclerosis, but less in inflammatory lesions. MR was better than CT in excluding pathology in cases of isolated calcification.

Magnetic resonance imaging of moyamoya disease in a child with Down's syndrome.

A case of Down's syndrome and associated moyamoya disease is described in a 2-year-old child. The condition was demonstrated by the non-invasive technique of magnetic resonance imaging.

[Detection of osteomyelitis and septic arthritis by nuclear magnetic resonance tomography in children]. / Kernspintomographischer Nachweis einer Osteomyelitis bzw. septischen Arthritis bei Kindern.

Suspected osteomyelitis or septic arthritis, respectively, is usually proven by means of clinical symptoms, laboratory data and microbiologic findings of blood cultures and joint fluids. In the early phase of the diseases conventional X-rays are not helpful. Imaging with isotopes is the most important procedure to describe localisation and extension of the inflammatory processes. Nuclear magnetic resonance imaging as a newer method is capable to detect these inflammatory processes very early, precisely and without discomfort for the patient. In four children with osteomyelitis and in one infant with septic arthritis, respectively, we were able to confirm the clinical diagnosis in a very early phase of the disease. In the patient with septic arthritis nuclear magnetic resonance was the only imaging procedure successfully localising the inflammatory process. Nuclear magnetic resonance imaging localises precisely inflammatory bone and joint diseases during the early stage of the disease.

Signal suppression of normal liver tissue by phase corrected inversion recovery: a screening technique.

A new pulse sequence characterized by simultaneous multislice spin echo (SE) and short inversion time (TI) with inversion recovery (STIR) acquisitions is demonstrated. For the STIR component, a repetition time of 1,000 ms and TI of 210 ms were chosen to suppress the signal from normal liver at 0.5 T and create a fast sequence suitable for screening purposes. Phase correction of the STIR with the SE's signal as a reference resulted in high contrast real IR images that were free of phase error artifact. In 13 min the entire liver could be imaged in 14 adjacent slices, each slice portrayed in an ensemble of four images: a T1-weighted SE image, IR real and modulus images, and a T1 map. Forty-one patients with liver pathology and 10 normal volunteers were examined with the sequence implemented on a commercially available 0.5 T imager (Gyroscan; Phillips). Images demonstrated high liver-lesion contrast and sensitivity to liver lesions. Lesions of less than 1 cm in diameter and lymphomatous lesions, commonly occult to magnetic resonance, were detected.

One-year MR imaging follow-up of patients with multiple sclerosis under cortisone therapy.

Twenty patients with relapsing/remitting course of MS were studied four times with MR imaging over the course of one year. First MR was undertaken during the acute relapse, afterwards patients were given cortisone therapy for four to six weeks. The second MR study followed 4-6 weeks after the first, the patients at this time being in remission. The third MR study was carried out 4 months after the first, the last scan one year after the first. The total number of lesions varied, though not greatly, over the whole follow-up, but there was an influence of the clinical course of MS on the pattern of lesions in MR imaging, mostly in respect to the number of confluences and the size of the lesions. Follow-up over one year showed that the inflammatory process produced an increase in the number of plaques, independent of the fact that most patients stayed in remission. A delayed effect of the cortisone therapy on the size, number, and confluence of plaques is suggested whilst clinical signs improved in most cases immediately after the beginning of drug therapy. Independent of the clinical course of the disease in some cases plaques previously seen vanished and others appeared in one and the same examination.

The value of T1-weighted images in the differentiation between MS, white matter lesions, and subcortical arteriosclerotic encephalopathy (SAE).

The aim of the study was to define reliable criteria for the differentiation of MR imaging between patients with MS and with "vascular" white matter lesions/SAE. We examined 35 patients with proven MS according to the Poser criteria and 35 patients with other white matter lesions and/or SAE. The result is that with MR a differentiation can be achieved provided that T1-weighted spin-echo sequences are included and the different pattern of distribution is considered. MS plaques are predominantly located in the subependymal region, vascular white matter lesions are mainly located in the water-shed of the superficial middle cerebral branches and the deep perforating long medullary vessels in the centrum semiovale. Infratentorial lesions are more often seen in MS. Confluence at the lateral ventricles is frequently accompanied by confluent abnormalities around the third ventricle, Sylvian aqueduct, and fourth ventricle, which is uncommon in SAE. In MS many lesions visible on T2-weighted images have a cellular or intracellular composition that renders them visible also on T1-weighted ones as regions with low signal intensity and more or less distinct boundary. "Vascular" white matter lesions and SAE mainly represent demyelination and can therefore be seen on T2-weighted images, but corresponding low signal intensity lesions on T1-weighted images are uncommon. In some exceptions there are such lesions with low signal representing lacunar infarcts or widened Virchow-Robin-spaces.

Angiomyolipoma of the kidney. Comparison between magnetic resonance imaging, computed tomography, and ultrasonography for diagnosis.

In six patients with angiomyolipoma of the kidney, five showed a typical pattern in T1, proton and T2 weighted images, with magnetic resonance imaging (MRI). Angiomyolipoma is recognized by its characteristic fatty tissue components, which result in high signal intensity in T1 and proton weighted images and a low signal in T2 weighted images. Five of the patients were also examined with ultrasonography (US); in four of these, the tumor could be recognized by its echodense pattern. Computed tomography (CT) was slightly less sensitive; three out of six examinations failed to produce a definite diagnosis. Instead of the typical low attenuation values of fat, Hounsfield units similar to either muscle or kidney tissue were observed in these 3 cases. In conclusion, the specific diagnosis of angiomyolipoma depends on the amount of fatty tissue present at MRI, CT, and sonography.

[Differential diagnosis of focal kidney diseases using nuclear magnetic resonance tomography]. / Differentialdiagnose fokaler Nierenerkrankungen mit der Kernspintomographie.

The value of T1 and T2-weighted spin echo sequences for making a specific diagnosis of focal renal disease was evaluated in 105 MR examinations. Typically, hypernephromas are characterised by a reduced or only slightly increased T1 or T2 signal, whereas previous bleeding and long-standing abscesses result in increased signal strength, particularly with T2-weighted sequences. In this way, hypernephromas can be characterised; this is not always possible with CT. Angiomyolipomas also have characteristic signals. MR has no advantages in the diagnosis of recent bleeding, acute focal inflammatory lesions, metastases, carcinoma of the renal pelvis or atypical cysts.