Influence of User-Defined Parameters on Diffusion Tensor Tractography of the Corticospinal Tract

This study discusses the influence of user-defined parameters on fiber tracking results obtained from a standard deterministic streamline tractography algorithm. Diffusion tensor imaging with fiber tractography was performed in five healthy volunteers. A region of interest was highlighted in the ventral part of the pons at the level of the middle cerebellar peduncle. The parameters studied were angle threshold, fractional anisotropy threshold, step length and number of seed samples per voxel. Changes in fiber tracts were described for increasing values per parameter. Increasing the angle threshold resulted in more and longer fibers. A higher fractional anisotropy threshold resulted in decreased length and fiber tracts that were not representative. Increasing the step length decreased the fiber continuity and altered its position. A higher number of seed samples per voxel resulted in a higher fiber tract density. When interpreting diffusion tensor images, the reader should understand the influence of user-defined settings on the results, and should be aware of the inter-dependency of fiber tracking parameters.

Social media for radiologists: an introduction

Abstract

Social media, which can be defined as dynamic and interactive online communication forums, are becoming increasingly popular, not only for the general public but also for radiologists. In addition to assisting radiologists in finding useful profession-related information and interactive educational material in all kinds of formats, they can also contribute towards improving communication with peers, clinicians, and patients. The growing use of social networking in healthcare also has an impact on the visibility and engagement of radiologists in the online virtual community. Although many radiologists are already using social media, a large number of our colleagues are still unaware of the wide spectrum of useful information and interaction available via social media and of the added value these platforms can bring to daily practice. For many, the risk of mixing professional and private data by using social media creates a feeling of insecurity, which still keeps radiologists from using them. In this overview we aim to provide information on the potential benefits, challenges, and inherent risks of social media for radiologists. We will provide a summary of the different types of social media that can be of value for radiologists, including useful tips on how to use them safely and efficiently.

Main Messages

• Online social networking enhances communication and collaboration between peers

• Social media facilitate access to educational and scientific information

• Recommendations and guidelines from policymakers and professional organisations are needed

• Applications are desired for efficient and secure exchange of medical images in social media

Pneumosinus dilatans in anterior skull base meningiomas

INTRODUCTION

Skull base meningiomas are often missed on non-contrast CT or MR examinations due to their close proximity to bone and low lesion to brain contrast. The purpose of this study is to illustrate that pneumosinus dilatans can be an indicator of anterior skull base meningiomas.

METHODS

A retrospective search of the radiology information system and picture archiving and computing system database was performed. Search terms were "meningioma" in association with "pneumosinus dilatans." Medical records and imaging studies were reviewed independently by two experienced neuroradiologists and were read in consensus. We recorded the patient age at the time of discovery of the meningioma, main presenting symptom(s), location of the tumor, and imaging characteristics. We also performed a comparative literature search for pneumosinus dilatans and its association with meningiomas.

RESULTS

Ten patients (six women; four men) were identified in whom a meningioma of the anterior skull base was associated with a pneumosinus dilatans. Three patients had multiple meningiomas, so a total of 14 intracranial tumors were identified. Mean age at discovery was 59 years with an age range of ± 20years. All meningiomas were diagnosed by MRI and/or CT.

CONCLUSION

Pneumosinus dilatans can be a helpful sign to indicate the presence of a meningioma of the anterior skull base.

Structured reporting: if, why, when, how-and at what expense? Results of a focus group meeting of radiology professionals from eight countries

Purpose

To determine why, despite growing evidence that radiologists and referring physicians prefer structured reporting (SR) to free text (FT) reporting, SR has not been widely adopted in most radiology departments.

Methods

A focus group was formed consisting of 11 radiology professionals from eight countries. Eight topics were submitted for discussion. The meeting was videotaped, transcribed, and analyzed according to the principles of qualitative healthcare research.

Results

Perceived advantages of SR were facilitation of research, easy comparison, discouragement of ambiguous reports, embedded links to images, highlighting important findings, not having to dictate text nobody will read, and automatic translation of teleradiology reports. Being compelled to report within a rigid frame was judged unacceptable. Personal convictions appeared to have high emotional value. It was felt that other healthcare stakeholders would impose SR without regard to what radiologists thought of it. If the industry were to provide ready-made templates for selected examinations, most radiologists would use them.

Conclusion

If radiologists can be convinced of the advantages of SR and the risks associated with failing to participate actively in its implementation, they will take a positive stand. The industry should propose technology allowing SR without compromising accuracy, completeness, workflows, and cost-benefit balance.

Main Messages

• Structured reporting offers radiologists opportunities to improve their service to other stakeholders.

• If radiologists can be convinced of the advantages of structured reporting, they may become early adopters.

• The healthcare industry should propose technology allowing structured reporting.

• Structured reporting will fail if it compromises accuracy, completeness, workflows or cost-benefit balance.

Grading and characterization of soft tissue tumors on magnetic resonance imaging: the value of an expert second opinion report

Objective

To retrospectively compare the accuracy of the initial MRI (magnetic resonance imaging) report of referring radiologists and the second opinion report.

Material and methods

MRI of 155 patients presenting with a soft tissue tumor (STT) in a single large community center were referred for inclusion in the Belgian Soft Tissue Neoplasm Registry (BSTNR). The initial report and the second opinion report were made independently. Histopathology (gold standard) was obtained in 90 patients (group 1). In 65 patients, the diagnosis was made by the combination of clinical findings and/or follow-up (group 2). In group 1, the concordance in grading and tissue-specific (TS) diagnosis between the referring center (RC) and expert center (EC) was reviewed.

Results

In group 1, MR grading yields a sensitivity of 100% and a specificity of 89% in the EC. The sensitivity was 88% and the specificity 81% in the RC. The accuracy was significantly higher in the EC (92%) compared to the RC (83%) (p = 0.039). The TS diagnosis was correct in 50% versus 38.5% of malignant tumors and in 71.8% versus 51.6% of benign tumors in the EC and RC respectively.

Conclusion

A second opinion report increases the accuracy in the diagnosis of STT on MRI.

Main Messages

• A second opinion MRI report increases the overall accuracy in the diagnosis of soft tissue tumors.

• There is a good overall agreement in MR grading between the referring and expert institution.

• In the expert center, there were fewer false-negative and false-positive diagnoses.

• MRI performs better in the tissue-specific diagnosis of benign versus malignant STT.

Impaired coronary flow reserve after a recent myocardial infarction: correlation with infarct size and extent of microvascular obstruction

BACKGROUND

The exact relationship between the coronary flow reserve (CFR) and infarct size remains unknown. In this prospective study the relationship between the CFR both in the infarcted and remote myocardium and infarct size was investigated. Furthermore, the diagnostic value of the CFR to predict the extent of microvascular obstruction (MO) was evaluated.

METHODS

In thirty patients the CFR was measured with a Doppler guide wire 6 ± 3 days after a first myocardial infarction (MI) in the infarct related and in a reference coronary artery. MO and infarct size were determined with magnetic resonance imaging.

RESULTS

The CFR was inversely related to infarct size in the infarcted and remote myocardium (respectively, r=-0.60, p<0.01 and r=-0.62, p<0.01). In the infarcted myocardium the extent of MO was strongly related to the infarct size and was in a multivariate analysis the single significant determinant of the CFR and the hyperaemic flow. In the remote myocardium no relationship was present between infarct size and hyperaemic flow, but the baseline flow increased as the infarct size became larger (r=0.58, p<0.01). In a receiver operator characteristic (ROC) analysis, a CFR value ≤ 2 in the infarct related coronary artery offered the best sensitivity (65%) and specificity (71%) to detect the presence of MO (p<0.05).

CONCLUSIONS

After MI, the CFR both in the infarcted and remote myocardium is inversely related to infarct size. In the infarcted myocardium, a CFR value ≤ 2 predicts the presence of MO with moderate sensitivity and specificity.

Methadone-induced toxic leukoencephalopathy: MR imaging and MR proton spectroscopy findings

We report the clinical, MR imaging, and proton MR spectroscopy findings in a middle-aged woman with proved methadone-induced toxic leukoencephalopathy. The imaging characteristics of this unusual condition have been reported only rarely in the medical literature. We show that the imaging findings in methadone-induced toxic leukoencephalopathy are similar, though not identical, to previously reported cases of neurologic deterioration due to heroin inhalation.

Panhypopituitarism apparently caused by hypophysitis masking a rapid development of a craniopharyngioma. A case report

We report the case of a 39-year-old male presenting with panhypopituitarism and diabetes insipidus. MR imaging showed focal thickening of the pituitary infundibulum and infiltration of the anterior pituitary lobe, suggesting hypophysitis. Hormonal replacement therapy induced a pronounced amelioration of general well-being. Eight months later the subject developed visual disturbances. MR imaging now showed a cystic sellar mass. Surgical drainage was performed. A second operation was necessary six weeks Later because of recurrent visual field defects. Diagnosis of papillary craniopharyngioma was finally made. This case demonstrates the remarkably rapid development of a craniopharyngioma, which initial radiological appearance was suggestive of hypophysitis. It also emphasizes the need of repeat MR examination in case of unusual presentation of hypopituitarism.

A neuroendocrine tumour of the sphenoid sinus and nasopharynx: a case report

It is rare for neuroendocrine tumours to originate in the sphenoid sinus and the nasopharynx. Neuroendocrine tumours can be classified into typical carcinoids, atypical carcinoids and small cell neuroendocrine carcinomas. Here we report the case of a 48-year-old man with a typical carcinoid tumour of the nasopharynx and sphenoid sinus. This is a very rare diagnosis, and only a few cases of a typical carcinoid in this region have been described in the literature.

Spontaneous closure of cerebral dural arteriovenous fistulas with direct cortical venous drainage. A case report

SUMMARY

We describe two rare cases of spontaneous closure of cerebral dural arteriovenous fistulas (DAVFs) with a small nidus and draining directly in a single cortical vein with several ectasias. Eighteen previously published cases of spontaneous closure of cerebral DAVF comprised more benign fistula types. In literature, several explanations for DAVF occlusion have been proposed. We hypothesize that, in addition to the known causes, the specific contrast medium used during the diagnostic selective angiography might have played a role in the thrombosis and subsequent fistula closure.

Tears of the supraspinatus tendon: assessment with indirect magnetic resonance arthrography in 67 patients with arthroscopic correlation

BACKGROUND

Magnetic resonance (MR) arthrography is generally regarded as the gold standard for shoulder imaging. As an alternative to direct MR arthrography, the less invasive indirect MR arthrography technique was proposed, offering logistic advantages because fluoroscopic or ultrasonographic guidance for joint injection is not required.

PURPOSE

To assess the diagnostic performance of indirect MR arthrography in the diagnosis of full- and partial-thickness supraspinatus tears in a symptomatic population.

MATERIAL AND METHODS

Two radiologists with different levels of experience independently and retrospectively interpreted indirect MR (1.5T) arthrograms of the shoulder obtained in 67 symptomatic patients who underwent subsequent arthroscopy. On MR, the supraspinatus tendon was evaluated for full- or partial-thickness tear. With arthroscopy as the standard of reference, sensitivity, specificity, and diagnostic accuracy of indirect MR arthrography in the detection of full- and partial-thickness tears of the supraspinatus tendon was calculated. Kappa (kappa) statistics were used for the assessment of the agreement between arthroscopic and imaging findings and for the assessment of interobserver agreement.

RESULTS

For full-thickness tears of the supraspinatus tendon, sensitivities, specificities, and accuracies exceeded 90% for both observers, with excellent interobserver agreement (kappa = 0.910). For partial-thickness tears, sensitivities (38-50%) and accuracies (76-78%) were poor for both reviewers, and interobserver agreement was moderate (kappa = 0.491). Discrepancies between MR diagnosis and arthroscopy were predominantly observed with small partial-thickness tears.

CONCLUSION

Indirect MR arthrography is highly accurate in the diagnosis of full-thickness rotator cuff tears. However, the diagnosis of partial-thickness tears with indirect MR arthrography remains faulty, because exact demarcation of degenerative change and partial rupture is difficult. On the basis of the above findings, we do not recommend indirect MR arthrography on patients for whom rotator cuff disease is suspected clinically.

Trauma of the spine and spinal cord: imaging strategies

Traumatic injuries of the spine and spinal cord are common and potentially devastating lesions. We present a comprehensive overview of the classification of vertebral fractures, based on morphology (e.g., wedge, (bi)concave, or crush fractures) or on the mechanism of injury (flexion-compression, axial compression, flexion-distraction, or rotational fracture-dislocation lesions). The merits and limitations of different imaging techniques are discussed, including plain X-ray films, multi-detector computed tomography (MDCT), and magnetic resonance imaging (MRI) for the detection. There is growing evidence that state-of-the-art imaging techniques provide answers to some of the key questions in the management of patients with spine and spinal cord trauma: is the fracture stable or unstable? Is the fracture recent or old? Is the fracture benign or malignant? In summary, we show that high-quality radiological investigations are essential in the diagnosis and management of patients with spinal trauma.