[Which imaging methods are safe in pregnant patients? A step-by-step plan to choose the right method]

Diagnostic imaging in pregnant patients often causes worries about radiation effects and IV contrast. We use a step-by-step plan to choose the right method and illustrate this with a case. First, we choose the method of imaging, non-ionizing imaging being preferred over ionizing. With ionizing radiation, the fetal dose is limited as much as possible with teratogenic and carcinogenic risk as low as possible (as low as reasonably achievable (ALARA)). The second consideration is whether intravenous contrast medium is necessary. The risks of the imaging procedure for the fetus (and patient) are compared with the risks for the patient (and fetus) without imaging. Furthermore, possible treatment changes are important. Finally, the patient is informed about the procedure, the necessity of it and possible negative effects for the fetus and patient. In our case these risks were minimal and it was not necessary to explicitly discuss them with the patient.

Predicting no return to sports after three months in patients with traumatic knee complaints in general practice by combining patient characteristics, trauma characteristics and knee complaints

Background: It remains unclear to what extent patients with traumatic knee complaints aged 18–45 years seen in general practice experience difficulties with return to sports.

Objectives: This study aims to determine the proportion of patients with a knee trauma that return to sports at six weeks and three months follow-up. Also examined were associations between no return to sports and baseline patient/trauma characteristics, knee complaints and MR (magnetic resonance) findings, as well as the additive value of MR findings.

Methods: Included were patients with traumatic knee complaints participating in a randomized controlled trial assessing the cost-effectiveness of an MR scan in general practice. Patients were classified as ‘no return to sports’ or ‘return to sports’ (sports on pre-injury or adapted level). Potential baseline predictors for no return to sports were assessed using logistic regression analyses. The area under the curves (AUC) was compared.

Results: At six weeks and three months follow-up, 147 (59%) and 175 (74%) patients, respectively, reported return to sports. Combining patient characteristics, trauma characteristics and knee complaints predicted no return to sports with an AUC of 0.86 (95%CI: 0.81–0.90) at six weeks and of 0.82 (95%CI: 0.76–0.88) at three months follow-up. After adding MR findings, the AUC was 0.79 (95%CI: 0.71–0.87) at six weeks and 0.79 (95%CI: 0.70–0.88) at three months follow-up.

Conclusion: Three out of four patients with a knee trauma in general practice reported return to sports at three months follow-up. A combination of patient/trauma characteristics and knee complaints predicted no return to sports, whereas MR findings had no additive value.

 

Trial registration: Dutch trial registration: registration number: NTR3689. registration date: 7 November 2012.

Clinical management of spinal metastases-The Dutch national guideline

This article is a summary of the revised Dutch multidisciplinary evidence-based guideline 'Spinal metastases' (English translation available at: https://www.oncoline.nl/spinal-metastases) that was published at the end of 2015. This summary provides an easy-to-use overview for physicians to use in their daily practice.

Does MRI add value in general practice for patients with traumatic knee complaints? A 1-year randomised controlled trial

OBJECTIVE

To determine whether referral to MRI by the general practitioner (GP) is non-inferior to usual care (no access to MRI by GPs) in patients with traumatic knee complaints regarding knee-related daily function.

METHODS

This was a multicentre, non-inferiority randomised controlled trial with 1-year follow-up. GPs invited eligible patients during or after their consultation. Eligible patients (18-45 years) consulted a GP with knee complaints due to a trauma during the previous 6 months. Patients allocated to the MRI group received an MRI at (median) 7 (IQR 1-33) days after the baseline questionnaire. Patients in the usual care group received information on the course of knee complaints, and a referral to a physiotherapist or orthopaedic surgeon when indicated. The primary outcome measure was knee-related daily function measured with the Lysholm scale (0 to 100; 100=excellent function) over 1 year, with a non-inferiority margin of 6 points.

RESULTS

A total of 356 patients were included and randomised to MRI (n=179) or usual care (n=177) from November 2012 to December 2015. MRI was non-inferior to usual care concerning knee-related daily function during 1-year follow-up, for the intention-to-treat (overall adjusted estimate: 0.33; 95% CI -1.73 to 2.39) and per-protocol (overall adjusted estimate: 0.06; 95% CI -2.08 to 2.19) analysis. There were no differences between both groups in the amount of patients visiting other healthcare providers.

CONCLUSION

MRI in general practice in patients with traumatic knee complaints was non-inferior to usual care regarding knee-related daily function during 1-year follow-up.

TRIAL REGISTRATION NUMBER

NTR3689.

General Practitioners Referring Adults to MR Imaging for Knee Pain: A Randomized Controlled Trial to Assess Cost-effectiveness

Purpose To determine the cost-effectiveness of early referral by the general practitioner for magnetic resonance (MR) imaging compared with usual care alone in patients aged 18-45 years with traumatic knee symptoms. Materials and Methods Cost-utility analysis was performed parallel to a prospective multicenter randomized controlled trial in Dutch general practice. A total of 356 patients with traumatic knee symptoms were included from November 2012 to December 2015 (mean age, 33 years ± 8 [standard deviation]; 222 men [62%]). Patients were randomly assigned to usual care (n = 177; MR imaging was not performed, but patients were referred to an orthopedic surgeon when conservative treatment was unsatisfactory) or MR imaging (n = 179) within 2 weeks after injury. Main outcome measures were quality-adjusted life years (QALYs) and costs from a healthcare and societal perspective. Multiple imputation was used for missing data. The Student t test was used to assess differences in mean QALYs, costs, and net benefits. Results Mean QALYs were 0.888 in the MR imaging group and 0.899 in the usual care group (P = .255). Healthcare costs per patient were higher in the MR imaging group (€1109) than in the usual care group (€837) (P = .050), mainly due to higher costs for MR imaging, with no reduction in the number of referrals to an orthopedic surgeon in the MR imaging group. Conclusion MR imaging referral by the general practitioner was not cost-effective in patients with traumatic knee symptoms; in fact, MR imaging led to more healthcare costs, without an improvement in health outcomes.

Combining independent decisions increases diagnostic accuracy of reading lumbosacral radiographs and magnetic resonance imaging

Diagnosing the causes of low back pain is a challenging task, prone to errors. A novel approach to increase diagnostic accuracy in medical decision making is collective intelligence, which refers to the ability of groups to outperform individual decision makers in solving problems. We investigated whether combining the independent ratings of chiropractors, chiropractic radiologists and medical radiologists can improve diagnostic accuracy when interpreting diagnostic images of the lumbosacral spine. Evaluations were obtained from two previously published studies: study 1 consisted of 13 raters independently rating 300 lumbosacral radiographs; study 2 consisted of 14 raters independently rating 100 lumbosacral magnetic resonance images. In both studies, raters evaluated the presence of "abnormalities", which are indicators of a serious health risk and warrant immediate further examination. We combined independent decisions of raters using a majority rule which takes as final diagnosis the decision of the majority of the group. We compared the performance of the majority rule to the performance of single raters. Our results show that with increasing group size (i.e., increasing the number of independent decisions) both sensitivity and specificity increased in both data-sets, with groups consistently outperforming single raters. These results were found for radiographs and MR image reading alike. Our findings suggest that combining independent ratings can improve the accuracy of lumbosacral diagnostic image reading.

Direct access to magnetic resonance imaging improved orthopaedic knee referrals in the Netherlands

BACKGROUND

The use of magnetic resonance imaging (MRI) in primary care is under debate, and the majority of GPs have no experience with MRI.

OBJECTIVES

To examine for which patients with knee injury an MRI is ordered and does direct access to MRI in primary care influence the GP referral to an orthopaedic surgeon?

METHODS

Consecutive patients with knee injury who underwent an MRI examination ordered by their GP were included. On the application form for MRI, the GPs indicated their referral intention in advance, as if MRI had not been available. Six months after the MRI scan, written interviews with the GPs were used to collect data on referrals and orthopaedic intervention. The number of patients finally referred to an orthopaedic surgeon in secondary care after MRI was compared with the number of intended referrals.

RESULTS

Of the 588 included, GPs referred fewer patients to the orthopaedic surgeon after receiving the MRI results than they would have done prior to MRI (60% versus 82.8%, P < 0.0001). The reduction was 16.1% for patients older than 50 years and 28.1% for patients younger than 50 years. Orthopaedic intervention was performed in 62.9% of all referred patients. Of the 101 patients whom the GP did not intend to refer prior to MRI, 48 were referred to an orthopaedic surgeon based on the MRI findings.

CONCLUSION

In patients with knee injury, direct access to MRI of the knee in a primary care setting significantly reduced referrals to an orthopaedic surgeon.

LEVEL OF EVIDENCE

Three prospective cohort.

Efficacy of MRI in primary care for patients with knee complaints due to trauma: protocol of a randomised controlled non-inferiority trial (TACKLE trial)

Background

Patients with traumatic knee complaints regularly consult their general practitioner (GP). MRI might be a valuable diagnostic tool to assist GPs in making appropriate treatment decisions and reducing costs. Therefore, this study will assess the cost-effectiveness of referral to MRI by GPs compared with usual care, in patients with persistent traumatic knee complaints.

Design and methods

This is a multi-centre, open-labelled randomised controlled non-inferiority trial in combination with a concurrent observational cohort study. Eligible patients (aged 18–45 years) have knee complaints due to trauma (or sudden onset) occurring in the preceding 6 months and consulting their GP. Participants are randomised to: 1) an MRI group, i.e. GP referral to MRI, or 2) a usual care group, i.e. no MRI. Primary outcomes are knee-related daily function, medical costs (healthcare use and productivity loss), and quality of life. Secondary outcomes are disability due to knee complaints, severity of knee pain, and patients’ perceived recovery and satisfaction. Outcomes are measured at baseline and at 1.5, 3, 6, 9 and 12 months follow-up. Also collected are data on patient demographics, GPs’ initial working diagnosis, GPs’ preferred management at baseline, and MRI findings.

Discussion

In the Netherlands, the additional diagnostic value and cost-effectiveness of direct access to knee MRI for patients presenting with traumatic knee complaints in general practice is unknown. Although GPs increasingly refer patients to MRI, the Dutch clinical guideline ‘Traumatic knee complaints’ for GPs does not recommend referral to MRI, mainly because the cost-effectiveness is still unknown.

Trial registration

Dutch Trial Registration: NTR3689.

[Using functional MRI to measure happiness]

In addition to MRI for use in diagnostic imaging we now also have functional MRI (fMRI) at our disposal. This can be used to map activity in different areas of the brain. Since its introduction, this technique has been used extensively in preoperative analysis of brain tumours. Emotional centres can also be mapped. Various applications and limitations of fMRI for studying emotions are discussed in this article.

'No-reflow' after acute myocardial infarction: direct visualisation of microvascular obstruction by gadolinium-enhanced CMR

Cardiovascular magnetic resonance is considered the standard imaging modality in clinical trials to monitor patients after acute myocardial infarction. However, limited data are available with respect to infarct size, presence and extent of microvascular injury (MVO) and changes over time, in relation to cardiac function in optimally treated patients. In the current study we prospectively investigate the change of infarct size over time, and the incidence and significance of MVO in a uniform, optimally treated patient group after AMI. (Neth Heart J 2008;16:179-81.).

[MRI diagnostics should be available to general practice]

With its high negative predictive value, MRI is of great value to the general practitioner's (GP) unequivocal task of excluding pathology in a large proportion of their patient population. While GPs prefer open access to MRI, insurance companies prefer to limit or discourage GP use of MRI, the main fear being unlimited unnecessary requests. Studies have shown these fears to be unfounded. Dutch Health Care Insurance Board (CVZ) regulations stipulate that GPs should have access to MRI on specific indications that are described in the Dutch College of General Practitioners' (NHG) practice guidelines. In the Netherlands, Alkmaar Medical Center (MCA) has offered open access to MRI since 1993 (knee) and 2006 (hernia nuclei pulposi), with excellent results. The percentage of normal report rates and of pathological findings of GPs is comparable to that of both neurologists and orthopaedic surgeons. Open access to MRI helps to speed up the diagnostic process, reduce outpatient waiting lists and limit unnecessary consultations. International publications have reported the cost-effectiveness of MRI. Experience both outside the Netherlands and at MCA has shown that open access to MRI results in reduced waiting lists and enhanced cost-effectiveness. This is best practice and should be incorporated into NHG practice guidelines.

Assessment of microvascular obstruction and prediction of short-term remodeling after acute myocardial infarction: cardiac MR imaging study

PURPOSE

To evaluate which cardiac magnetic resonance (MR) imaging technique for detection of microvascular obstruction (MVO) best predicts left ventricular (LV) remodeling after acute myocardial infarction (MI).

MATERIALS AND METHODS

This study had local ethics committee approval; all patients gave written informed consent. Sixty-three patients with first acute MI, treated with primary stent placement and optimal medical therapy, underwent cine MR imaging at 4-7 days and at 4 months after MI. Presence of MVO was qualitatively evaluated at baseline by using three techniques: (a) a single-shot saturation-recovery gradient-echo first-pass perfusion sequence (early hypoenhancement), mean time, 1.09 minutes +/- 0.07 (standard deviation) after contrast material administration; (b) a three-dimensional segmented saturation-recovery gradient-echo sequence (intermediate hypoenhancement), mean time, 2.17 minutes +/- 0.26; and (c) a two-dimensional segmented inversion-recovery gradient-echo late gadolinium enhancement sequence (late hypoenhancement), mean time, 13.32 minutes +/- 1.26. Contrast-to-noise ratios (CNRs) were calculated from the signal-to-noise ratios of the infarcted myocardium and MVO areas. Univariable linear regression analysis was used to identify the predictive value of each MR imaging technique.

RESULTS

Early hypoenhancement was detected in 44 (70%) of 63 patients; intermediate hypoenhancement, in 39 (62%); and late hypoenhancement, in 37 (59%). Late hypoenhancement was the strongest predictor of change in LV end-diastolic and end-systolic volumes over time (beta = 14.3, r = 0.40, P = .001 and beta = 11.3, r = 0.44, P < .001, respectively), whereas intermediate and late hypoenhancement had comparable predictive values of change in LV ejection fraction (beta = -3.1, r = -0.29, P = .02 and beta = -2.8, r = -0.27, P = .04, respectively). CNR corrected for spatial resolution was significantly superior for late enhancement compared with the other sequences (P < .001).

CONCLUSION

By using cardiac MR imaging, late hypoenhancement is the best prognostic marker of LV remodeling, with highest CNR between the infarcted myocardium and MVO regions.

Functional recovery after acute myocardial infarction: comparison between angiography, electrocardiography, and cardiovascular magnetic resonance measures of microvascular injury

OBJECTIVES

We examined the relation between angiographic, electrocardiographic, and gadolinium-enhanced cardiovascular magnetic resonance (CMR) characteristics of microvascular obstruction (MVO), and their predictive value on functional recovery after acute myocardial infarction (AMI).

BACKGROUND

Microvascular obstruction on CMR has been shown to predict left ventricular (LV) remodeling, but it is not well known how it compares with commonly used criteria of microvascular injury, and earlier reports have produced conflicting results on the significance and extent of MVO.

METHODS

Thrombolysis In Myocardial Infarction (TIMI) flow grade, myocardial blush grade (MBG), and ST-segment resolution were assessed in 60 patients with AMI treated with primary stenting. Cardiovascular magnetic resonance was performed between 2 and 9 days after revascularization to determine early MVO on first-pass perfusion imaging, late MVO on late gadolinium-enhanced imaging, and infarct size and transmural extent. Cine imaging was used to determine LV volumes and global and regional function at baseline and 4-month follow-up.

RESULTS

Early and late MVO were both related to incomplete ST-segment resolution (p = 0.002 and p = 0.01, respectively), but not to TIMI flow grade and MBG. Of all angiographic, electrocardiographic, and CMR variables, late MVO was the strongest parameter to predict changes in end-diastolic volume (beta = 0.53; p = 0.001), end-systolic volume (beta = 8.67; p = 0.001), and ejection fraction (beta = 3.94; p = 0.006) at follow-up. Regional analysis showed that late MVO had incremental diagnostic value to transmural extent of infarction (odds ratio: 0.18; p < 0.0001).

CONCLUSIONS

In patients after revascularized AMI, late MVO proved a more powerful predictor of global and regional functional recovery than all of the other characteristics, including transmural extent of infarction.

Late Gadolinium-Enhanced Cardiovascular Magnetic Resonance Evaluation of Infarct Size and Microvascular Obstruction in Optimally Treated Patients after Acute Myocardial Infarction

PURPOSE

Cardiovascular magnetic resonance (CMR) is considered the standard imaging modality in clinical trials to monitor patients after acute myocardial infarction (AMI). However, limited data is available with respect to infarct size, presence, and extent of microvascular injury (MVO), and changes over time, in relation to cardiac function in these optimally treated patients. In this study, we prospectively investigate the change of infarct size over time, and the incidence and significance of MVO in a uniform, optimally treated patient group after AMI.

METHODS

Forty patients underwent cine and late gadolinium-enhanced CMR within 9 days and at 4 months after primary stenting. Left ventricular ejection fraction (LVEF), infarct size (IS) and MVO size were calculated.

RESULTS

IS decreased with 19.0% at follow-up (p<0.01). The 23 (57.5%) patients with MVO had larger infarct size, higher left ventricular volumes and lower LVEF and more involution of IS at follow-up. Overall, LVEF improved from 42.3+/-9.8% to 44.0+/-9.8% (p=0.06), irrespective of presence or size of MVO.

CONCLUSION

Infarct size reduces over time by 19.0% in optimally treated patients after AMI. Despite optimal reperfusion, MVO was found in the majority of patients. Although patients with MVO had larger infarcts and worse indices of left ventricular remodelling, functional change at follow-up was comparable to patients without MVO.

Role of Radiology in a National Initiative to Interdict Drug Smuggling: The Dutch Experience

OBJECTIVE

The purpose of this pictorial essay is to describe the role of radiology in a national initiative to intercept illegal narcotics concealed within the bodies of human transporters.

CONCLUSION

Radiologic examination is increasingly important in identifying intracorporeal drug smuggling as improved wrapping techniques undermine the usefulness of blood and urine testing and clinical observation. Detection rates of high accuracy, sensitivity, and specificity are achieved by experienced radiologists.

Interobserver agreement on the radiological criteria of the International Panel on the diagnosis of multiple sclerosis

We assessed the interobserver agreement on the radiological part of the International Panel (IP) criteria for the diagnosis of multiple sclerosis (MS), comprising the assessment of dissemination in space (DIS) and time (DIT) based exclusively on MRI. Four radiologists trained and four radiologists naive in the application of the IP criteria scored the fulfillment for DIS (i.e., > or =3 periventricular, > or =1 infratentorial, > or =1 juxtacortical, > or = 1 enhancing lesion or a total of > or =9 T2-weighted lesions) and DIT (presence of new or enhancing lesions at follow-up) in baseline and two follow-up scans from 20 patients suspected for having MS. The IP-trained radiologists agreed at least moderately on all assessments (kappa>0.40), whereas the IP-naive radiologists showed fair agreement (kappa<0.40) on five of 16 assessments. In the final conclusion on DIS and DIT, the IP-trained radiologists agreed substantially on both items (kappa=0.62 and kappa=0.60, respectively) compared with a fair agreement on DIS (kappa=0.29) and moderate agreement on DIT (kappa=0.52) among the IP-naive radiologists. Given the poor interobserver agreement among IP-naive observers, the new IP criteria for MS require additional training and should perhaps be simplified.

Reliability and validity of lumbosacral spine radiograph reading by chiropractors, chiropractic radiologists, and medical radiologists

STUDY DESIGN

A cross-sectional diagnostic study was conducted in two sessions.

OBJECTIVE

To determine and compare the reliability and validity of contraindications to chiropractic treatment (infections, malignancies, inflammatory spondylitis, and spondylolysis-listhesis) detected by chiropractors, chiropractic radiologists, and medical radiologists on plain lumbosacral radiographs.

SUMMARY OF BACKGROUND DATA

Plain radiography of the spine is an established part of chiropractic practice. Few studies have assessed the ability of chiropractors to read plain radiographs.

METHODS

Five chiropractors, three chiropractic radiologists and five medical radiologists read a set of 300 blinded lumbosacral radiographs, 50 of which showed an abnormality (prevalence, 16.7%), in two sessions. The results were expressed in terms of reliability (percentage and kappa) and validity (sensitivity and specificity).

RESULTS

The interobserver agreement in the first session showed generalized kappas of 0.44 for the chiropractors, 0.55 for the chiropractic radiologists, and 0.60 for the medical radiologists. The intraobserver agreement showed mean kappas of 0.58, 0.68, and 0.72, respectively. The difference between the chiropractic radiologists and medical radiologists was not significant. However, there was a difference between the chiropractors and the other professional groups. The mean sensitivity and specificity of the first round, respectively was 0.86 and 0.88 for the chiropractors, 0.90 and 0.84 for the chiropractic radiologists, and 0.84 and 0.92 for the medical radiologists. No differences in the sensitivities were found between the professional groups. The medical radiologists were more specific than the others.

CONCLUSIONS

Small differences with little clinical relevance were found. All the professional groups could adequately detect contraindications to chiropractic treatment on radiographs. For this indication, there is no reason to restrict interpretation of radiographs to medical radiologists. Good professional relationships between the professions are recommended to facilitate interprofessional consultation in case of doubt by the chiropractors.

Comparison of sonography and magnetic resonance imaging for the diagnosis of partial tears of finger extensor tendons in rheumatoid arthritis

OBJECTIVE

Finger extensor tenosynovitis in rheumatoid arthritis (RA) may lead to partial and eventually to complete tendon tears. The aim of this study was to investigate the diagnostic value of sonography (SG) and/or magnetic resonance imaging (MRI) to visualize partial tendon tears.

METHODS

Twenty-one RA patients with finger extensor tenosynovitis for more than 12 months underwent SG, MRI and surgical inspection, the latter being the gold standard.

RESULTS

For partial tears, sensitivity and specificity were 0.27 and 0.83 for MRI, and 0.33 and 0.89 for SG, respectively. Positive and negative predictive values were 0.35 and 0.78 for MRI, and 0.50 and 0.80 for SG, respectively. Accuracy was 0.69 for MRI and 0.75 for SG.

CONCLUSION

For visualization of partial finger extensor tendon tears in RA patients, SG performs slightly better than MRI, but both techniques are at present not sensitive enough to be used in daily practice.

Sonography and magnetic resonance imaging equivalent for the assessment of full-thickness rotator cuff tears

OBJECTIVE

To investigate the diagnostic value of sonography (SG) and magnetic resonance imaging (MRI) in the assessment of full-thickness rotator cuff tears (RCTs).

METHODS

Twenty-one consecutive, otherwise healthy patients with noninflammatory unilateral chronic (>3 months) shoulder complaints due to a possible full-thickness RCT were studied (9 women and 12 men, mean +/- SD age 56 +/- 12). According to standardized procedures, SG was performed by both a radiologist and a rheumatologist, and MRI was evaluated by 2 radiologists. All assessors were blinded to the patient's diagnosis. Within 3 weeks after SG and MRI, arthroscopy was performed. SG, MRI, and arthroscopy results were scored as negative or positive for the presence of a full-thickness RCT. The result of surgical inspection was used as the "gold standard."

RESULTS

For full-thickness RCTs, the sensitivity was 0.81 for SG and 0.81 for MRI. The specificity was 0.94 for SG and 0.88 for MRI. The positive predictive value was 0.96 for SG and 0.91 for MRI. The negative predictive value was 0.77 for SG and 0.74 for MRI. Accuracy was 0.86 for SG and 0.83 for MRI.

CONCLUSION

Full-thickness RCTs can be identified accurately by both SG and MRI. Because of its low cost and because it can be performed in the rheumatology unit, SG seems to be a promising diagnostic tool for use by the rheumatologist.

Cortical lesions in multiple sclerosis

Although previous studies have shown that the lesions of multiple sclerosis may involve the cerebral cortex, there is little published research on the prevalence and distribution of such lesions. Using neuropathological techniques and MRI, a series of studies has been undertaken in order to assess this, in particular to identify their relationship to cortical veins. A serial MRI study showed that the use of gadolinium proffered an increase in cortical lesion detection of 140% and showed that 26% of active lesions arose within or adjacent to the cortex. In a post-mortem study, MRI under-reported lesions subsequently analysed neuropathologically, particularly those arising within the cortex. In a further 12 cases examined, 478 cortical lesions were identified, of which 372 also involved the subcortical white matter. Seven different lesion types were identified; the majority arose within the territory of the principal cortical veins, whilst the remaining quarter arose within the territory of the small branch or superficial veins. Small cortical lesions are common in multiple sclerosis and are under-reported by MRI. Investigation of the cortical venous supply shows how such lesions may arise, and why the majority also involve the underlying white matter.

Remote expert consultation for MRI procedures by means of teleradiology

From April 1992 to January 1993, radiology expert opinion for MRI procedures was offered by means of teleradiology. The experiment was carried out in addition to an existing service of a mobile MRI unit. MRI images were sent by means of teleradiology via regular telephone lines from the mobile MRI unit to an academic hospital, which served as expert consultation centre. During this period, 43 requests for expert opinions were performed. This article describes the clinical effects of these expert opinions, and the technical and organisational requirements to perform teleradiology in daily clinical practice.

Toxic leukoencephalopathy after inhalation of poisoned heroin: MR findings

Retrospective MR studies of four patients with neurologic symptoms after inhalation of contaminated heroin vapor revealed extensive, typically symmetrical lesions in the white matter of the cerebrum, cerebellum, and midbrain. Selective involvement of the corticospinal tract, the solitary tract, and the lemniscus medialis also has been found.

Gadolinium-DTPA enhanced magnetic resonance imaging of bone cysts in patients with rheumatoid arthritis

OBJECTIVES

To examine the contents of intraosseous cysts in patients with rheumatoid arthritis (RA) through the signal intensity characteristics on gadolinium-DTPA (Gd-DTPA) enhanced magnetic resonance imaging.

METHODS

The hand or foot joints of nine patients with the cystic form of RA (where the initial radiological abnormality consisted of intraosseous cysts without erosions) were imaged before and after intravenous administration of Gd-DTPA. A 0.6 unit, T1 weighted spin echo and T2* weighted gradient echo were used to obtain images in at least two perpendicular planes.

RESULTS

Most cysts showed a low signal intensity on the non-enhanced T1 weighted (spin echo) images and a high signal intensity on the T2* weighted (gradient echo) images, consistent with a fluid content. No cyst showed an enhancement of signal intensity on the T1 weighted images after intravenous administration of Gd-DTPA, whereas synovium hyperplasia at the site of bony erosions did show an increased signal intensity after Gd-DTPA. Magnetic resonance imaging detected more cysts (as small as 2 mm) than plain films, and the cysts were located truly intraosseously. In six patients no other joint abnormalities were identified by magnetic resonance imaging; the three other patients also showed, after Gd-DTPA administration, an enhanced synovium at the site of bony erosions.

CONCLUSIONS

It is suggested that intraosseous bone cysts in patients with RA do not contain hyperaemic synovial proliferation. The bone cysts in patients with the cystic form of RA may be the only joint abnormality.

Angiotropic intravascular large-cell lymphoma with massive cerebral extension

Angiotropic intravascular large-cell lymphoma (AILL) is a rare, generally fatal disease characterised by a multifocal proliferation of neoplastic mononuclear cells within small blood vessels. The diagnosis of a patient was made at necropsy. The malignant cells had infiltrated the periventricular areas of the brain.

Presentation and course of AIDS dementia complex: 10 years of follow-up in Amsterdam, The Netherlands

OBJECTIVE

To assess the clinical presentation and course of the AIDS dementia complex (ADC).

DESIGN

Retrospective study of a consecutive series of symptomatic HIV-1-infected patients [Centers for Disease Control and Prevention (CDC) stages IVA, B, C and D] evaluated for neurological symptoms between 1982 and 1992.

SETTING

An academic referral centre for AIDS.

PATIENTS

A total of 536 symptomatic HIV-1-infected patients evaluated for neurological symptoms between 1982 and 1992.

INTERVENTIONS

Zidovudine treatment, which was introduced in The Netherlands on 1 May 1987 for patients with severe symptoms of HIV infection (CDC stages IVA, B, C and D).

MAIN OUTCOME MEASURES

Diagnosis of ADC and CD4 cell count, clinical features, neuropsychological abnormalities, computed tomography (CT) and magnetic resonance imaging (MRI) abnormalities, cerebrospinal fluid (CSF) findings and course in patients with ADC.

RESULTS

ADC was diagnosed in 40 out of 536 (7.5%) immunosuppressed, neurologically symptomatic HIV-1-infected patients in CDC stage IV, and was the AIDS-defining illness in six. The mean CD4 cell count of the 40 patients with ADC was 109 x 10(6)/l. Neuropsychological abnormalities in 15 out of 17 patients tested were in accordance with subcortical dementia. On CT scan of the brain, 70% showed no or only mild cortical atrophy. MRI was more sensitive than CT scan for detecting white matter abnormalities (73 versus 35%; P = 0.02). CSF examination showed mononuclear pleocytosis in 25%, protein level increase in 55%, and HIV-1 p24 core protein in 38% (13 out of 34). The mean survival was 6.7 months in the 40 ADC patients, but 4 months in 20 patients who had never used zidovudine, compared with 14.8 months in 10 patients who started zidovudine after they were classified as having ADC (P < 0.001). Three of these 10 patients improved remarkably, and two slightly, after starting zidovudine. ADC developed after discontinuation of zidovudine in nine patients. Only one patient developed ADC while receiving 600 mg zidovudine.

CONCLUSIONS

MRI is more sensitive than CT for detecting white matter abnormalities. To date, there is no specific or sensitive CSF marker for ADC. Zidovudine may improve symptoms and prolong survival in patients with ADC, which rarely developed with continued zidovudine use in our study.

Methotrexate induced brain necrosis and severe leukoencephalopathy due to disconnection of an Ommaya device

A 63-year old woman with breast carcinoma developed leucoencephalopathy and local brain necrosis after intraparenchymal infusion of methotrexate. This iatrogenic condition was caused by drain disconnection of the Ommaya device (bore hole type). The diagnosis of this rare complication of an Ommaya device was based on multiplanar MR-imaging. The case is discussed with regard to the complications of intraventricular chemotherapy by means of an Ommaya reservoir.

A double-blind, comparative study of gadodiamide injection and gadopentetate dimeglumine in MRI of the central nervous system

Seventy-nine patients with known or suspected central nervous system lesions were studied with MRI in a phase III double-blind study. Forty were given gadopentetate dimeglumine (Gd-DTPA) and 39 gadodiamide injection (Gd-DTPA BMA), a new low-osmolar nonionic contrast enhancing medium. The dosage was 0.1 mmol/kg body weight, corresponding to 0.2 ml/kg. Spin-echo sequences were performed before and immediately after injection. The safety and efficacy of the two contrast media were assessed. No changes were observed in blood pressure, heart rate or neurological status. Five adverse effects (two episodes of headaches, two of nausea and one of dizziness) were reported by 2 patients who received gadodiamide injection and 1 who received gadopentetate dimeglumine. All events were mild and their relationship to the contrast media was uncertain. For both contrast media statistically significant changes in serum iron were observed 24 h after injection. More than 70% of the patients had abnormal findings on MRI, and in 56% of these contrast enhancement of the abnormal structure or lesion was seen. Contrast enhancement provided the diagnosis in about 50%, changed it in 40% and increased diagnostic confidence in 95%.

MR imaging of skeletal metastases from medulloblastoma

The findings of MR imaging in 3 patients with bone metastases from medulloblastoma are reported. The first patient showed focal lesions of low signal intensity on T1-weighted spin echo images at a time when bone scintigraphy was negative for metastases. This patient later developed extensive osteosclerotic lesions visible on plain films. The bone marrow of the second patient showed diffuse low signal intensity on T1-weighted images. After chemotherapy the signal intensity of the bone marrow increased which correlated with a return of normal hematopoietic tissue. A response to chemotherapy was also found on MR imaging and repeat bone marrow biopsies in a third patient. A consistent finding was a low signal intensity on pre-gadolinium images, but the pattern (focal or diffuse abnormal signal intensity) was different in each patient. To our knowledge, this is the first report on MR imaging findings in bone metastases from medulloblastoma.

White matter lesions on magnetic resonance imaging in clinically diagnosed Alzheimer's disease. Evidence for heterogeneity

In a prospective magnetic resonance imaging (MRI) study we evaluated the prevalence and severity of white matter changes in 29 patients with Alzheimer's Disease (AD) and 24 age-matched healthy elderly, all without cerebrovascular risk factors. The AD patients were divided into two groups according to age at onset of symptoms, one with presenile onset AD (n = 13) and one with senile onset AD (n = 16), who were matched for dementia severity. Signal hyperintensities were rated using a semiquantitative scoring method, separately in the periventricular region (PVH) and in the lobar white matter (WMH), as well as in the basal ganglia (BGH) and in the infratentorial region (ITFH). Cortical atrophy as a parameter of grey matter involvement was rated on a 0 (absent) to 3 (severe) scale. We found PVH, WMH and BGH scores to be significantly higher in senile onset AD patients than in age-matched controls. By means of multiple linear logistic regression we found that PVH, WMH and BGH scores were significantly dependent on the diagnosis of senile onset AD, while the PVH score also showed a significant age dependency. Cortical atrophy did not differ significantly between presenile onset AD and senile onset AD patients. These results indicate that presenile onset AD and senile onset AD patients differ with respect to white matter involvement, but not with respect to grey matter involvement on MRI. Since cerebrovascular risk factors were excluded these findings may indicate that senile onset AD patients display more small vessel involvement (arteriolosclerosis) than presenile onset AD patients, suggesting additional (microvascular) factors for the dementia syndrome in senile onset AD. Our data lend support to the growing body of evidence that AD is heterogeneous, consisting of at least two types. Based on our findings two forms can be distinguished: (i) a 'pure' form of the disease, usually with early disease onset, and no more white matter changes than normal for age; (ii) a 'mixed' form, usually with disease onset later in life, and showing more white matter changes on MRI than normal for age.