Cost analysis of vestibular schwannoma screening with contrast-enhanced magnetic resonance imaging in patients with asymmetrical hearing loss.

BACKGROUND: Vestibular schwannomas are a rare cause of asymmetrical hearing loss, and routine screening with magnetic resonance imaging can be costly. This paper reports results on vestibular schwannoma screening at our institution and compares the cost of screening to a utility of hearing benefit. METHOD: All screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss between 2006 and 2011 were retrospectively reviewed. The cost per new vestibular schwannoma diagnosis was calculated. The cost per patient for those who benefitted from intervention was estimated based on rates of hearing preservation reported in the literature. RESULTS: Forty-five (4.3 per cent) of 1050 screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss were positive for vestibular schwannoma, and the cost per new diagnosis was $11,436. The estimated screening cost per patient for those who benefitted from surgery or radiation was $147,030, while US federal compensation for unilateral hearing loss was $44,888. CONCLUSION: Although we achieved a lower screening cost per new diagnosis than reported in the current literature, there remains disparity between the screening cost per benefitted patient and the 'benefit' of hearing.

Detection of carotid artery calcification on the panoramic images of post-menopausal females is significantly associated with severe abdominal aortic calcification: a risk indicator of future adverse vascular events.

OBJECTIVES: Outcome studies among post-menopausal females with calcified carotid artery plaque (CCAP) on their panoramic images have not been previously undertaken. We sought to compare the extent of abdominal aortic calcification (AAC) on lateral lumbar spine radiographs (LLSRs), among groups of females with (CCAP+) and without (CCAP-) carotid lesions on their panoramic images. "Severe" levels of AAC have previously been validated as a risk indicator of future adverse cardiovascular events. METHODS: This cross-sectional case-control study included a "CCAP+ group" consisting of females more than 50 years of age having the carotid lesion diagnosed by their dentists and an atherogenic risk factor (age, body mass index, hypertension, diabetes and dyslipidaemia)-matched "CCAP- group". A physician radiologist, using the Framingham index, evaluated the LLSRs for the magnitude of AAC. Summary statistics for key variables were computed and conditional logistic regression techniques were considered. RESULTS: Members of the CCAP+ group were significantly (p=0.038) more likely to demonstrate "severe" levels of AAC on their LLSRs than members of the CCAP group. CONCLUSIONS: This is the first published study demonstrating that CCAP on panoramic images of post-menopausal females is significantly associated with "severe" levels of AACs on LLSRs independent of traditional risk factors. Given that these levels of AAC are a validated risk indicator of future myocardial infarction and stroke, dentists must evaluate the panoramic images of post-menopausal females for the presence of CCAP. Patients with carotid atheromas should be referred to their physicians for further evaluation given the systemic implications.

Imaging of the internal carotid artery: the dilemma of total versus near total occlusion.

PURPOSE: To evaluate ultrasonography (US) and magnetic resonance (MR) angiography in the differentiation between occlusion and near occlusion of internal carotid artery (ICA). MATERIALS AND METHODS: Consecutive patients with occlusion or near occlusion of ICA at catheter angiography and who underwent MR angiography and US were included. MR angiography and US were compared with catheter angiography, the standard, for the ability to help distinguish occlusion from near occlusion. Noninvasive examinations were evaluated for the ability to classify near occlusions as having severe focal stenosis with distal luminal collapse versus diffuse nonfocal disease. The 95% CIs were calculated. RESULTS: In 55 of 274 patients with 548 ICAs, catheter angiography depicted 37 total occlusions and 21 near occlusions. US depicted all total occlusions; MR angiography depicted 34 (92%) (95% CI: 0.78, 0.98). US depicted 18 (86%) of 21 (95% CI: 0.64, 0.97) near occlusions; MR angiography depicted all (100%). Of 18 vessels that were determined to be patent at US, 17 (94%) (95% CI: 0.73, 0.99) were classified as having focal stenosis or diffuse disease. Because flow gaps were identified in vessels with focal and diffuse disease, MR angiography was not effective in helping to differentiate these lesions. CONCLUSION: Assuming US is the initial imaging examination, when occlusion is diagnosed, MR angiography can depict it. If occlusion is confirmed, no further imaging is necessary. US performed well in helping to differentiate vessels with focal severe stenosis from those with diffuse disease. MR angiography added little in this group. Catheter angiography remains beneficial for vessels with diffuse nonfocal narrowing.

Ability to use duplex US to quantify internal carotid arterial stenoses: fact or fiction?

PURPOSE: To determine if duplex ultrasonography (US) can help predict the degree of internal carotid arterial (ICA) stenosis. MATERIALS AND METHODS: ICA peak systolic velocity (PSV) and the ratio of the PSV in the ICA to that in the ipsilateral common carotid artery (VICA/VCCA) were compared with the degree of arteriographically measured stenosis. ICAs were arteriographically subgrouped at 10% incremental levels of stenosis and broader ranges. Mean PSV, VICA/VCCA, and SDs were calculated for each category. Histograms showing the numbers of stenotic ICAs in subgroups and for vessels with stenoses of greater than or equal to or less than 70% narrowing were constructed. The number of vessels correctly subgrouped with typical Doppler US thresholds was calculated. RESULTS: Mean PSV and VICA/VCCA increased with stenosis level (P < .01); SDs were wide. Histograms showed Doppler US values in the central groups across all disease levels. Histograms differentiating at least or less than 70% stenosis showed minimal overlap. PSV and VICA/VCCA helped classify, respectively, 185 and 181 of 204 vessels with stenoses of less than 50%, 15 and 21 of 46 vessels with stenoses of 50%-69%, and 73 and 67 of 84 vessels with stenoses of 70% or greater. When classifying stenoses as 69% or less or 70% or more, PSV and VICA/VCCA were correct in 90.6% and 90.3% of vessels. CONCLUSION: Doppler US is excellent for classifying stenoses as above or below a single degree of severity but does not function well in stenosis subclassification.

Cerebral gangliogliomas: preoperative grading using FDG-PET and 201Tl-SPECT.

PURPOSE: To date there have been only scattered case reports comparing the nuclear medicine characteristics of gangliogliomas with their histologic grade. We sought to determine the relative usefulness of nuclear medicine scanning, CT, and MR imaging in predicting the histologic grade of these tumors. METHODS: Eleven cases of pathologically proved ganglioglioma were analyzed retrospectively. Preoperative positron emission tomography with 18-fluorodeoxyglucose (FDG-PET), thallium chloride Tl 201 single-photon emission computed tomography (201Tl-SPECT), CT, and MR imaging studies were reviewed and compared with histologic tumor grade. FDG-PET scans were inspected visually for tumor metabolic activity relative to activity of normal gray and white matter. 201Tl-SPECT scans were analyzed for tumor activity using regions of interest and activity ratios. CT and MR studies were reviewed for the presence of conventional radiologic features of malignancy (ie, enhancement and edema). RESULTS: Eleven patients had a total of 15 nuclear scans. Eight of nine gangliogliomas scanned with FDG-PET showed tumor hypometabolism, the ninth was normal. All nine were low-grade gangliogliomas. Increased 201Tl-SPECT activity was seen in two high-grade gangliogliomas. The third 201Tl-SPECT scan, of a low-grade ganglioglioma, was normal. CT and MR studies showed enhancement in four gangliogliomas, of which two were high grade and two low grade. Edema was seen only in conjunction with the two high-grade gangliogliomas. CONCLUSION: FDG-PET and 201Tl-SPECT are 100% correlative in preoperative prediction of histologic grade of ganglioglioma. Tumors with decreased or normal PET or SPECT activity were low grade; tumors with increased SPECT activity were high grade. These results may be more reliable than CT and MR imaging findings in assessing tumor grade, and they may be of value for surgical planning and determining patient prognosis.

Immunosuppressant neurotoxicity in liver transplant recipients. Clinical challenges for the consultation-liaison psychiatrist.

Neuropsychiatric problems are common among liver transplant recipients, and immunosuppressant neurotoxicity is an important etiologic factor in the posttransplant period. Four typical cases of immunosuppressant neurotoxicity are presented from the clinical experience of the University of California, Los Angeles-Dumont Liver Transplant program. All patients presented with acute behavioral symptoms and received urgent psychiatric consultation; each proved to be suffering from a variant of immunosuppressive-related neurotoxicity. Correlative neuroimaging studies and descriptions of clinical course are included. Psychiatrists are urged to become familiar with the signs, symptoms, differential diagnosis, neuroimaging findings, and management of immunosuppressive neurotoxicity and secondary psychiatric disorders in solid organ recipients.

Transcranial color Doppler imaging of brain arteriovenous malformations in adults.

This study was performed to investigate the utility of transcranial color Doppler sonography in evaluating adult cerebral arteriovenous malformations. Twelve patients with such malformations underwent sonography. Spectral Doppler sonographic assessment included peak systolic velocity, end diastolic velocity, and resistive index within the intracranial and extracranial vessels. Color Doppler sonography was used to visualize the site of shunting. Paired and unpaired Student's t-tests were used to determine significance of spectral findings. The nidus was seen in eight of 10 pial malformations. The nidi in two patients were located in the parietal region and not visualized. When compared with the corresponding contralateral artery, feeding arteries (identified in all 10 of the pial lesions) demonstrated diminished resistive indices (P = 0.09). Similarly, the end diastolic velocity was increased in all feeding arteries (P = 0.03). When compared with published normal values, the peak systolic and end diastolic velocities were significantly elevated and the resistive indices were low (P < 0.0003). Transcranial color Doppler sonography depicted the nidi of pial arteriovenous malformations in 80% of cases. Feeding arteries demonstrated abnormal peak systolic velocity, end diastolic velocity, and resistive index in all cases when compared with published values. Transcranial color Doppler sonography is not a good screening tool due to limited acoustical window, but it may be useful for noninvasive study of the physiology of arteriovenous malformations as they are treated.

Assessment of intraaxial and extraaxial brain lesions with digitized computed tomographic images versus film: ROC analysis.

RATIONALE AND OBJECTIVES: The authors evaluated the diagnostic accuracy of viewing computed tomographic (CT) scans as film versus soft-copy images at a workstation. METHODS: Receiver operating characteristic analysis of the interpretation of 202 CT scans (103 were normal, 99 were abnormal) by five neuroradiologists was performed. Abnormal images contained high- or low-attenuation intraaxial lesions or extraaxial fluid (subdural, subarachnoid, or epidural hemorrhage). Hard copies were read on a standard light box, and digital images were examined at a 1,024 x 1,250 workstation. Lesion location and type and confidence ratings were recorded on a worksheet. RESULTS: There were no statistically significant differences in diagnostic accuracy between the two display modes. Reader performance was slightly better with the workstation in the assessment of low-attenuation lesions. CONCLUSION: Diagnostic accuracy is similar for CT scans displayed at a workstation and those displayed as hard copy in the assessment of subtle intra- and extraaxial brain lesions.