MR imaging of cerebral tumors: state of the art and work in progress

Risk Factors for Perceptual-versus-Interpretative Errors in Diagnostic Neuroradiology

BACKGROUND AND PURPOSE

Diagnostic errors in radiology are classified as perception or interpretation errors. This study determined whether specific conditions differed when perception or interpretation errors occurred during neuroradiology image interpretation.

MATERIALS AND METHODS

In a sample of 254 clinical error cases in diagnostic neuroradiology, we classified errors as perception or interpretation errors, then characterized imaging technique, interpreting radiologist's experience, anatomic location of the abnormality, disease etiology, time of day, and day of the week. Interpretation and perception errors were compared with hours worked per shift, cases read per shift, average cases read per shift hour, and the order of case during the shift when the error occurred.

RESULTS

Perception and interpretation errors were 74.8% (n = 190) and 25.2% (n = 64) of errors, respectively. Logistic regression analyses showed that the odds of an interpretation error were 2 times greater (OR, 2.09; 95% CI, 1.05-4.15; P = .04) for neuroradiology attending physicians with ≤5 years of experience. Interpretation errors were more likely with MR imaging compared with CT (OR, 2.10; 95% CI, 1.09-4.01; P = .03). Infectious/inflammatory/autoimmune diseases were more frequently associated with interpretation errors (P = .04). Perception errors were associated with faster reading rates (6.01 versus 5.03 cases read per hour; P = .004) and occurred later during the shift (24th-versus-18th case; P = .04).

CONCLUSIONS

Among diagnostic neuroradiology error cases, interpretation-versus-perception errors are affected by the neuroradiologist's experience, technique, and the volume and rate of cases read. Recognition of these risk factors may help guide programs for error reduction in clinical neuroradiology services.

ProApolipoprotein A1: a serum marker of brain metastases in lung cancer patients

BACKGROUND

Central nervous system (CNS) diagnostics is a promising tool for detection of neurological disorders, including brain metastases. One of the earliest applications of CNS diagnostics was based on serum markers of blood-brain barrier (BBB) dysfunction, which often correlates with acute, chronic, or incipient brain disease. In the case of brain metastases, serum levels of S100beta demonstrated a good negative predictive value comparable to radiologic investigations. However, a confounding factor was the presence of BBB changes due to cerebrovascular disease.

METHODS

Of 103 patients enrolled in a lung cancer study, greater than 50% presented with magnetic resonance imaging (MRI) changes consistent with chronic cerebrovascular disease and reflected by elevated serum S100beta. To unveil serum protein, the authors used proteomic techniques that allow discrimination between patients with brain metastases and lung cancer patients affected by cerebrovascular ischemic changes without infiltrating tumor.

RESULTS

ProApolipoprotein A1, transferrin, haptoglobin, and transthyretin were upregulated in patients affected by chronic cerebrovascular disease and brain metastases compared with those affected only by vascular diseases. ProApolipoprotein A1 was significantly increased (p<.05) in patients with CNS disease.

CONCLUSIONS

In conclusion, these data support the use of serum markers for the early detection of brain metastases. ProApolipoprotein A1 may be used in conjunction with S100beta for serum-based, MRI-independent diagnosis of metastatic brain tumors.

Meningiomas: Updating Basic Science, Management, and Outcome

BACKGROUND

Meningiomas are biologically complex and clinically and surgically challenging. These features, combined with the rewarding potential for cure, make them of great interest to neurologists, neurosurgeons, and neuroscientists alike.

REVIEW SUMMARY

Initially, we review the clinical context of meningiomas, particularly recent changes in histopathological classification, diagnosis, and neuroimaging. Secondly, the underlying basic science as it has evolved over the last decades is summarized. The status of areas recently of intense interest, such as steroid hormone receptors and oncogenic viruses is described. Additionally, emerging areas of great promise, such as cytogenetics and molecular biology are presented. Lastly, we describe recent advances in management. In particular, skull-base surgery, image-guided surgery, and advances in radiotherapy are emphasized. The possible impact of basic research on management and outcome is also outlined.

CONCLUSIONS

Although usually benign and amenable to cure, meningiomas still present significant diagnostic and treatment challenges. Advances in basic science, surgery, and adjuvant therapy are widening the potential for safe, effective, evidence-based management leading to even better outcomes

Diagnostic accuracy of MRI compared to CCT in patients with brain metastases

OBJECTIVES

In patients with extracranial neoplasms, the occurrence and number of brain metastases (BM) are critical for further diagnostic approaches and therapeutic strategies and the patient's prognosis. Although widely accepted, there is surprisingly little evidence in the literature that MRI is superior to CCT. Therefore, in patients with solitary BM according to diagnostic contrast-enhanced computed tomography (CCT), we investigated, what additional information could be gained by contrast-enhanced magnetic resonance imaging (MRI).

METHODS/RESULTS

Among 55 patients with solitary BM according to CCT, 17 had multiple BM on MRI (31%) and 38 had solitary BM in both. Based on a presumed binomial distribution of our data, we calculated a rate of at least 19% of patients with solitary BM on CCT, in which MRI would show multiple lesions (p = 0.05). The two main characteristics for BM missed by CCT were the smaller diameter, which averages 2 cm less than in BM identified with both modalities, and a preferential frontotemporal location.

CONCLUSION

MRI is indeed superior to CCT in the diagnosis of BM the essential reasons besides detection of smaller lesions being a better soft tissue contrast, significantly stronger enhancement with paramagnetic contrast agents, the lack of bone artifacts, fewer partial volume effects, and direct imaging in three different planes. Therefore, MRI is indispensable in the diagnostic workup of patients with BM for choosing the optimum therapeutic approach, especially with regard to the decision whether to operate or to primarily irradiate the patient's metastases.

Review of skull base surgery approaches: with special reference to pediatric patients

The techniques of skull base surgery attempt to maximize the exposure of a cranial base lesion while using the least amount of brain retraction. Cranial base surgery is not a 'new' area of neurosurgical or otolaryngologic interest, but instead represents a resurgence of efforts to treat difficult lesions involving the cranial base. This resurgence of interest and effort is a product of recent advances in microanatomical knowledge of the cranial base, advances in microsurgical technique, improved neurophysiologic monitoring, and improved collaborative relationships between neurosurgery, otolaryngology and plastic surgery. Furthermore, improved neuroanesthetic techniques allow the surgeon to proceed with surgery without undue concern about time, and improved neuroimaging techniques provide the surgeon with detailed knowledge of the three dimensional characteristics of the tumor and surrounding structures. This review will focus on the surgical management of cranial base tumors primarily affecting the pediatric population. Little has been written on the techniques of skull base surgery as they apply to the pediatric population, since cranially-based tumors are a relatively rare occurrence in this patient population. In most instances, however, many of the 'standard' skull base approaches can be applied to the pediatric patient with few modifications, and in our experience, the pediatric patients have tolerated these approaches as well as their adult counterparts.

Meningiomas

This article reviews the recent literature on the pathogenesis and pathology of meningiomas, contemporary techniques of surgical resection, and new nonsurgical treatments, including radiation and hormone therapy. Factors predisposing to meningioma formation include female sex, previous ionizing radiation, and Type 2 neurofibromatosis. The first factor may act through the expression of sex hormone receptors, especially the progesterone receptor, in these tumors; the other two probably act by causing a deletion on Chromosome 22. The pathological classifications of meningiomas include the traditional division into histological subtypes and the World Health Organization classification that selects characteristics that may lead to recurrence. There is an increasing emphasis on proliferative indices and other characteristics that may predict aggressive behavior in these tumors. On computed tomography, meningiomas are enhancing, well-marginated, dural-based lesions that may have considerable surrounding edema; the cause of the edema is uncertain but may result from secretory products of the tumor. Magnetic resonance imaging with enhancement will demonstrate these lesions accurately and can be used for three-dimensional reconstruction as well. Computed tomography and magnetic resonance imaging have largely replaced angiography in the preoperative diagnosis of meningiomas, but angiographic embolization may be a useful operative adjunct. Although meningioma surgery is sometimes thought of as benign and curative, the reported surgical mortality rate is as high as 14.3% and the reported 10-year survival rate after surgery varies from 43 to 77%. Surgery has advanced most in the management of suprasellar, cavernous sinus, clivus, tentorial, and posterior fossa meningiomas, because new approaches and a better understanding of anatomy have allowed more radical resection. There is still substantial morbidity associated with surgery in these regions, however, and the long-term recurrence rates are still unknown for these new radical techniques. For convexity, parasagittal, lateral sphenoid wing, and olfactory groove meningiomas, complete resection should be the goal and operative morbidity appears to be low. There is a high recurrence rate after surgery. With apparent total removal, the recurrence rate varies from 9 to 20% at 10 years, with subtotal resection varying from 18.4 to 50%. The degree of resection appears to be most important in recurrence, but histopathological features are also important. Recently, radiation therapy has been recognized as a useful adjunct to surgery, and with radiosurgical techniques may become more important in the future. Antiprogesterone therapy appears to have had some success as well, and it or other hormonal therapy may be another future option for residual or recurrent meningiomas.