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Biomedical subjects

J T Wilmink

Publications and source records attributed to J T Wilmink.

At least 19 recordsLinked to original sources
PubMed2006

MR angiography of the great anterior radiculomedullary artery (Adamkiewicz artery) validated by digital subtraction angiography.

BACKGROUND AND PURPOSE: Imaging of the anterior superficial spinal cord arteries by MR angiography is hindered by their small calibers and the similarity in configuration with the anterior superficial spinal cord veins. To validate the location and spatial configuration of the great anterior radiculomedullary artery, (ie, the Adamkiewicz artery [AKA]), contrast-enhanced MR angiography (CE-MRA) was compared with digital subtraction angiography (DSA). METHODS: Fifteen patients with suspected spinal cord vascular pathology underwent both spinal CE-MRA and selective spinal DSA. Two phase CE-MRA was performed with the use of a centric k-space filling scheme synchronized to the contrast bolus arrival. The level and side of the AKA origin were scored on the DSA and CE-MRA images and compared regarding image quality in terms of vessel conspicuity, contrast, continuity, sharpness, and background homogeneity on a relative 5-point scale. RESULTS: Localization and spatial configuration of the AKA by CE-MRA was in agreement with DSA findings in 14 of 15 cases. One mismatch of 1 vertebral level (not side) appeared as a result of the tangled vascular pathology. Comparison of image quality revealed that DSA is superior to CE-MRA concerning vessel continuity, sharpness, and background homogeneity (P < .001). Overall vessel conspicuity and contrast were judged to be similar. CONCLUSION: CE-MRA can visualize and localize the level of the AKA correctly. Image quality of CE-MRA is sufficient for detection of the AKA but is inferior to DSA.

Adult↗
PubMed2002

The ex utero intrapartum treatment (EXIT) procedure in fetal neck masses: a case report and review of the literature.

Large fetal neck masses can cause airway obstructions with potential fetal demise after delivery. The relationship of the neck mass to airway structures can be defined prenatally with ultrasound and magnetic resonance imaging (MRI). The ex utero intrapartum treatment (EXIT) procedure can be used to obtain a fetal airway while feto-maternal circulation is preserved to optimise fetal outcome. We present a case in which prenatally a large fetal neck mass was diagnosed on ultrasound and a successful EXIT procedure was performed. A review of the literature is given and the prenatal use of ultrasonography and MRI in case of fetal neck masses is discussed.

Adult↗
PubMed2002

Prognostic value of MRI findings in sciatica.

The natural course of sciatica due to disc herniation is generally favourable but individually unpredictable. Some patients recover only after prolonged conservative therapy or surgery. This study aims to ascertain whether magnetic resonance (MR) imaging features can be used to predict outcome of sciatica and help to identify patients unlikely to respond to conservative management. For a transversal diagnostic study 274 primary care patients underwent early MR imaging for leg pain. One hundred and thirty-three patients with sciatica were followed for 3 months, both patients and physicians being unaware of MR imaging findings. At 12 weeks a favourable prognosis was indicated by the following features: annular rupture (P= 0.02) and nerve root compression on MR imaging (P = 0.03). Poor prognosis was indicated by disc herniation in the foramen (P = 0.004). Our findings show that early MR imaging features are related to prognosis. However, the associations are not strong enough to justify routine use of early MR imaging to predict the prognosis of sciatica.

Adolescent↗
PubMed2002

Diagnostic value of history and physical examination in patients suspected of lumbosacral nerve root compression.

OBJECTIVE: To evaluate patient characteristics, symptoms, and examination findings in the clinical diagnosis of lumbosacral nerve root compression causing sciatica. METHODS: The study involved 274 patients with pain radiating into the leg. All had a standardised clinical assessment and magnetic resonance (MR) imaging. The associations between patient characteristics, clinical findings, and lumbosacral nerve root compression on MR imaging were analysed. RESULTS: Nerve root compression was associated with three patient characteristics, three symptoms, and four physical examination findings (paresis, absence of tendon reflexes, a positive straight leg raising test, and increased finger-floor distance). Multivariate analysis, analysing the independent diagnostic value of the tests, showed that nerve root compression was predicted by two patient characteristics, four symptoms, and two signs (increased finger-floor distance and paresis). The straight leg raise test was not predictive. The area under the curve of the receiver-operating characteristic was 0.80 for the history items. It increased to 0.83 when the physical examination items were added. CONCLUSIONS: Various clinical findings were found to be associated with nerve root compression on MR imaging. While this set of findings agrees well with those commonly used in daily practice, the tests tended to have lower sensitivity and specificity than previously reported. Stepwise multivariate analysis showed that most of the diagnostic information revealed by physical examination findings had already been revealed by the history items.

Adolescent↗
PubMed2001

MR imaging of alar ligament in whiplash-associated disorders: an observer study.

Rotational CT studies have been previously used in whiplash-associated disorders (WAD) to document rotatory instability of the upper cervical spine thought to be due to alar ligamentous injury. More recently MR imaging has been employed to image such injury more directly. Our study aimed to assess the reliability and reproducibility of such MRI findings. In 12 WAD patients and six asymptomatic controls the alar ligaments were imaged in the coronal plane with an 0.5-T MRI system using a quadrature neck coil and applying a fast spin echo proton density/T2-weighted sequence (TR/TE/ETL 2,500/18 ms/16, FOV 140 mm, matrix 200 x 256, 16 x 3 mm slices, scan time 25 min). Images were graded for symmetry of imaging plane using a 3-point scale and also for presence of ligamentous injury with a 4-point scale, by two independent observers on two separate occasions. The alar ligaments could be identified in all cases. Asymmetry of the imaging plane was found to some degree in over half of the cases. Such images were much more likely to be graded as indicating injury. Of a total of 72 assessments, clearly and probably normal grades were given in 75%, and clearly or probably abnormal grades in 25%. Kappa values for intra- and inter-observer agreement were moderate to very poor, however, and the grading system could not reliably distinguish between patients and controls. It was concluded that with MRI techniques presently employed, alar ligamentous damage as a causative factor in WAD has not been proven.

Adolescent↗
PubMed2001

The internal vertebral venous plexus prevents compression of the dural sac during atlanto-axial rotation.

Deformation of the extradural space and the possibility of impression upon the dural sac during atlanto-axial rotation are investigated. Atlanto-axial rotation leads to a reduction in the cross-sectional area of the bony spinal canal of approximately 40%. Atlanto-axial rotation was recorded by endocanalar views from a video camera fixed inside the skull of six unembalmed cadavers. Axial thin-section T1-weighted MRI slice sets were acquired from three volunteers (mid-position and maximal left and right rotation of the head and cervical spine). The axial cross-sectional areas of the bony spinal canal, dural sac and spinal cord were measured. In two other persons post-gadolinium contrast-enhanced T1-weighted MRI volume scans with fat-suppression prepulse were acquired (mid-position and rotation) to determine venous contents of the extradural space. The 50:50 ratio between left and right extradural halves in mid-position changed to an ipsilateral:contralateral ratio of 20:80 in maximum rotation at the level just above the lateral C1-C2 joints. Directly below these joints the opposite occurred. The post-contrast studies showed an enhancing internal vertebral venous plexus (IVVP), which almost completely occupied the extradural space at the atlanto-axial level. This could not be shown in the cadaver experiments, because of absence of blood and cerebrospinal fluid (CSF) pressure. During atlanto-axial rotation blood displacement in the IVVP allows major deformations of the extradural space. This prevents dural sac impression.

Aged↗
PubMed2001

Slight cognitive impairment and magnetic resonance imaging abnormalities but normal school levels in children treated for acute lymphoblastic leukemia with chemotherapy only.

OBJECTIVES: To investigate persistent neuropsychologic late effects in children treated for acute lymphoblastic leukemia at a young age with chemotherapy only by means of serial neuropsychologic assessments (NPAs), magnetic resonance imaging (MRI) of the brain, and evaluation of school levels. STUDY DESIGN: Consecutive patients (n = 17) had 2 extensive NPAs (12 psychometric measures) after cessation of therapy. Test results were compared with those of both healthy control subjects and 28 previously treated children who received cranial irradiation. MRI findings were related to test scores. School levels were evaluated in the patients and their healthy siblings. RESULTS: Initial participation (n = 17) and availability of the study group after 8 years of follow-up were 100%. Significant group differences between patients who received chemotherapy and healthy control subjects were found for memory and fine-motor functioning. The 17 patients combined showed 16 deficits on various test measures. MRI abnormalities were seen in 6 children, but these did not correlate with cognitive performance. No differences in school levels were seen when the patients who received chemotherapy were compared with their siblings. The current nonirradiated patients demonstrated significantly better test results and significantly fewer learning disabilities and MRI abnormalities than did the previously irradiated group. CONCLUSION: Treatment with chemotherapy only may be associated with some cognitive impairment. However, these children attained normal school levels.

Antineoplastic Agents↗
PubMed2001

Teaching anatomy; a clinicians view.

The General Plan Anatomy as defined by the Netherlands Association of Anatomists and published in the European Journal of Morphology in 1999 is a good starting point for discussion between anatomists and clinicians to define what is indispensable anatomical knowledge for a competent physician. The plan to teach anatomy within a clinical context and to relate form and structure on function makes learning anatomy more attractive and will have a greater appeal for the student. The list of discipline-related objectives is too extensive for a general practitioner whereas parts of this list are too limited for related medical specialists. Teaching anatomy and teaching clinical sciences and expertise must become more integrated.

Anatomy↗
PubMed2001

MR imaging, single-photon emission CT, and neurocognitive performance after mild traumatic brain injury.

BACKGROUND AND PURPOSE: Mild traumatic brain injury (mTBI) (Glasgow Coma Scale = 14-15) is a common neurologic disorder and a common cause of neurocognitive deficits in the young population. Most patients recover fully from mTBI, but 15% to 29% of patients have persistent neurocognitive problems. Although a partially organic origin is considered likely, little brain imaging evidence exists for this assumption. The aims of the present study were to establish the prevalence of posttraumatic lesions in mTBI patients on MR images and to assess the relation between these imaging findings and posttraumatic symptoms. Secondly, we explored the value of early posttraumatic single-photon emission CT (SPECT) for the evaluation of mTBI. METHODS: Twenty-one consecutive patients were included in the study. Patients underwent MR examination, technetium-99m hexamethylpropylene amine oxime SPECT, and neurocognitive assessment within 5 days after injury. Neurocognitive follow-up was conducted 2 and 6 months after injury, and MR imaging was repeated after 6 months. Lesion size and brain atrophy were measured on the MR studies. RESULTS: Twelve (57%) of 21 patients had abnormal MR findings, and 11 (61%) of 18 had abnormal SPECT findings. Patients with abnormal MR or SPECT findings had brain atrophy at follow-up. The mean neurocognitive performance of all subjects was within normal range. There was no difference in neurocognitive performance between patients with normal and abnormal MR findings. Patients with abnormal MR findings only showed significantly slower reaction times during a reaction-time task. Seven patients had persistent neurocognitive complaints and one patient met the criteria for a postconcussional syndrome. CONCLUSION: Brain lesions are common after mTBI; up to 77% of patients may have abnormal findings either on MR images or SPECT scans, and these lesions may lead to brain atrophy. The association between hypoperfusion seen on acute SPECT and brain atrophy after 6 months suggests the possibility of (secondary) ischemic brain damage. There is only a weak correlation between neuroimaging findings and neurocognitive outcome.

Adolescent↗
PubMed2000

[Thrombolytic therapy in patients with acute brain infarction: favorable preliminary results in Maastricht].

OBJECTIVE: To assess the feasibility of acute thrombolysis for ischaemic stroke in clinical practice. DESIGN: Prospective. METHOD: On July 1st, 1998 thrombolytic therapy for ischaemic stroke was introduced in the University Hospital Maastricht, the Netherlands. All patients admitted with ischaemic stroke were prospectively registered during the first year. Of all patients with ischaemic stroke, it was determined how many were potentially eligible for thrombolysis within 3 hours of stroke symptom onset, and how many of these patients were actually treated with thrombolysis. Furthermore, the reasons for exclusion from thrombolytic therapy were assessed. Several baseline and clinical patient characteristics were noted. RESULTS: During the first year 18 ischaemic stroke patients were treated with thrombolysis within 3 hours of stroke onset. These 18 patients constituted 7% of all 256 ischaemic stroke patients and 18% of the potentially eligible patients who arrived in the hospital within 3 hours. More than 40% of the ischaemic stroke patients were not eligible for thrombolysis due to late arrival in the hospital. There were no major complications in the 18 treated patients: 3 patients developed an asymptomatic haemorrhagic transformation of the infarct. CONCLUSION: Acute thrombolysis for ischaemic stroke within 3 hours from stroke onset is feasible, and can under specific conditions be applied in clinical practice. Only 7% of all ischaemic stroke patients underwent thrombolysis. This percentage of patients could be increased by an earlier presentation of patients to the hospital.

Adult↗
PubMed2000

On the pathogenesis of brain tumour cysts: a volumetric study of tumour, oedema and cyst.

Chemical analysis of brain tumour cyst contents has invalidated the concept of cyst formation being the result of tumour necrosis, and a common mechanism of vasogenic brain oedema and cyst formation, namely blood-brain barrier (BBB) disruption, has been suggested. To analyse a possible relationship between the occurrence of vasogenic oedema and the presence of cysts, we performed a volumetric analysis on the MRI and CT studies of 60 patients with primary or metastatic brain tumours. We compared four groups of tumours: 30 gliomas, of which 15 were cystic and 15 not and 30 metastatic brain tumours of which 15 were cystic and 15 not. Although the mean volume of oedema was similar for cystic and noncystic tumours, the ratio of oedema to tumour volume was approximately four times as high in cystic supratentorial tumours. This would support the view that cyst formation may be related to relatively greater production of oedema, possibly due to fusion of microcysts containing oedema fluid. The ratio of oedema to tumour volume is not greater in cystic cerebellar and intraventricular tumours. This may be due to the different anatomical organization of the cerebellar white matter, and the fact that the intraventricular tumours are bordered by subcortical grey matter. In these cases, spread of oedema is impeded. Formation of a large amount of brain oedema is therefore not an essential prerequisite for cyst formation.

Adolescent↗
PubMed2000

Asymptomatic brain metastases (BM) in small cell lung cancer (SCLC): MR-imaging is useful at initial diagnosis.

PURPOSE: In this study we evaluated the usefulness of MR-imaging in the detection of asymptomatic brain metastases (BM) at the initial diagnosis in patients with small cell lung cancer (SCLC) and studied the follow-up of these patients. PATIENTS AND METHODS: One-hundred and twenty-five patients with SCLC were investigated with MR-imaging. RESULTS: In 112 patients with normal neurological findings, MR-imaging of the brain demonstrated BM in 17 patients (15%). Six of these 17 patients were therefore upgraded to extensive disease (ED). Two of these 17 patients died during chemotherapy because of progressive disease and 3 patients became neurologic symptomatic with progressive disease on MR-imaging of the brain. After completion of chemotherapy a repeated MR-imaging of the brain in the remaining 12 patients showed 1 complete remission, 4 partial remission and 7 progressive disease of the BM. CONCLUSION: This study showed that at presentation an unexpectedly high percentage of SCLC patients had asymptomatic BM on MR-imaging. We propose that MR-imaging of the brain should be included in the staging of SCLC patients as well for staging, prognosis and therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Value of radiological diagnosis of skull fracture in the management of mild head injury: meta-analysis.

OBJECTIVES: Head injury is a common event. Most patients sustain a mild head injury (MHI), and management depends on the risk of an intracranial haemorrhage (ICH). The value of a plain skull radiograph as a screening tool for ICH is controversial. The aim of this meta-analysis was to estimate and explain differences in reported sensitivity and specificity of the finding of a skull fracture for the diagnosis of ICH, in order to assess the value of the plain skull radiograph in the investigation of patients with MHI, and to estimate the prevalence of ICH in these patients. METHOD: After a systematic literature search 20 studies were selected that reported data on the prevalence of ICH after MHI and/or data on the diagnostic value of skull fracture for the diagnosis of ICH. The mean prevalence of ICH weighted for the sample size was determined. The sensitivity and specificity of different studies were combined using a summary receiver operator characteristic curve. Correlation analysis was used to determine factors that could explain the reported differences between studies. RESULTS: The weighted mean prevalence of ICH after MHI is 0.083. The potential for verification bias and the percentage of patients who had suffered loss of consciousness or post-traumatic amnesia were the most significant factors explaining interstudy differences in sensitivity and specificity. Based on studies wherein at least 50% of patients had a CT study of the brain, the estimated sensitivity of a radiographic finding of skull fracture for the diagnosis of ICH is 0.38 with a corresponding specificity of 0.95. CONCLUSION: The plain skull radiograph is of little value in the initial assessment of MHI patients.

Humans↗
PubMed2000

Cognitive performance in relation to MRI temporal lobe volume in schizophrenic patients and healthy control subjects.

The aim of this study was to identify whether specific deficits in cognitive processing are present in schizophrenia and whether these are related to the volume of temporal and limbic structures. Twenty-seven schizophrenic outpatients were compared with 19 matched control subjects. Compared with control subjects, patients performed complex tasks disproportionately worse than they performed simple tasks. No group differences were found with regard to temporal and limbic volume. Volume of the parahippocampal gyrus was correlated with cognitive performance. The findings are interpreted as evidence for a dysfunction in the maintenance of task-relevant information and the inhibition of irrelevant information.

Adult↗
PubMed2000

Pathoanatomy of clinical findings in patients with sciatica: a magnetic resonance imaging study.

OBJECT: Anatomical details of nerve root compression may explain the production of the signs and symptoms of sciatica. The authors of anatomical studies have offered many theories without clearly demonstrating the clinical relevance of the observations. Clinicoanatomical series are scarce and are affected to a great extent by selection bias. METHODS: The authors created a schematic drawing of the lumbar anatomy based on both the literature and in vitro anatomical observations. A diagnosis was then made with the aid of detailed and standardized clinical and magnetic resonance (MR) imaging studies in primary-care patients who presented with pain that radiated into the leg. Clinical and MR imaging findings were correlated. Finally, the anatomical drawing was compared with the clinical data. The higher the vertebral level of symptomatic disc herniations, the more likely the compression will be more laterally situated. Classic symptoms of sciatica (typically, dermatomal pain; increase in pain when coughing, sneezing, or straining; and testing positive for pain during straight leg raising) were most likely to occur with compression of the nerve root in the axilla and with mediolateral disc herniations. CONCLUSIONS: The L-3, L-4, L-5, and S-1 nerve roots each tend to be compressed at different sites along the rostrocaudal course of the nerve root. Disc herniations become symptomatic at different sites for each disc level. The schematic drawing produced a priori could well be used to explain these findings. Expectations of particular clinical findings can be predicted by specific pathoanatomical findings.

Adult↗
PubMed1999

Lack of effectiveness of bed rest for sciatica.

BACKGROUND AND METHODS: Bed rest is widely advocated for sciatica, but its effectiveness has not been established. To study the effectiveness of bed rest in patients with a lumbosacral radicular syndrome of sufficient severity to justify treatment with bed rest for two weeks, we randomly assigned 183 subjects to either bed rest or watchful waiting for this period. The primary outcome measures were the investigator's and patient's global assessments of improvement after 2 and 12 weeks, and the secondary outcome measures were changes in functional status and in pain scores (after 2, 3, and 12 weeks), absenteeism from work, and the need for surgical intervention. Neither the investigators who assessed the outcomes nor those involved in data entry and analysis were aware of the patients' treatment assignments. RESULTS: After two weeks, 64 of the 92 patients in the bed-rest group (70 percent) reported improvement, as compared with 59 of the 91 patients in the control (watchful-waiting) group (65 percent) (adjusted odds ratio for improvement in the bed-rest group, 1.2; 95 percent confidence interval, 0.6 to 2.3). After 12 weeks, 87 percent of the patients in both groups reported improvement. The results of assessments of the intensity of pain, the bothersomeness of symptoms, and functional status revealed no significant differences between the two groups. The extent of absenteeism from work and rates of surgical intervention were similar in the two groups. CONCLUSIONS: Among patients with symptoms and signs of a lumbosacral radicular syndrome, bed rest is not a more effective therapy than watchful waiting.

Absenteeism↗