Combined Orbital and Cranial Vessel Wall Magnetic Resonance Imaging for the Assessment of Disease Activity in Giant Cell Arteritis.

OBJECTIVE: Acute visual impairment is the most feared complication of giant cell arteritis (GCA) but is challenging to predict. Magnetic resonance imaging (MRI) evaluates orbital pathology not visualized by an ophthalmologic examination. This study combined orbital and cranial vessel wall MRI to assess both orbital and cranial disease activity in patients with GCA, including patients without visual symptoms. METHODS: Patients with suspected active GCA who underwent orbital and cranial vessel wall MRI were included. In 14 patients, repeat imaging over 12 months assessed sensitivity to change. Clinical diagnosis of ocular or nonocular GCA was determined by a rheumatologist and/or ophthalmologist. A radiologist masked to clinical data scored MRI enhancement of structures. RESULTS: Sixty-four patients with suspected GCA were included: 25 (39%) received a clinical diagnosis of GCA, including 12 (19%) with ocular GCA. Orbital MRI enhancement was observed in 83% of patients with ocular GCA, 38% of patients with nonocular GCA, and 5% of patients with non-GCA. MRI had strong diagnostic performance for both any GCA and ocular GCA. Combining MRI with a funduscopic examination reached 100% sensitivity for ocular GCA. MRI enhancement significantly decreased after treatment (P < 0.01). CONCLUSION: In GCA, MRI is a sensitive tool that comprehensively evaluates multiple cranial structures, including the orbits, which are the most concerning site of pathology. Orbital enhancement in patients without visual symptoms suggests that MRI may detect at-risk subclinical ocular disease in GCA. MRI scores decreased following treatment, suggesting scores reflect inflammation. Future studies are needed to determine if MRI can identify patients at low risk for blindness who may receive less glucocorticoid therapy.

Assessment of treatment response to dendritic cell vaccine in patients with glioblastoma using a multiparametric MRI-based prediction model.

PURPOSE: Autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) is a promising treatment modality for glioblastomas. The purpose of this study was to investigate the potential utility of multiparametric MRI-based prediction model in evaluating treatment response in glioblastoma patients treated with DCVax-L. METHODS: Seventeen glioblastoma patients treated with standard-of-care therapy + DCVax-L were included. When tumor progression (TP) was suspected and repeat surgery was being contemplated, we sought to ascertain the number of cases correctly classified as TP + mixed response or pseudoprogression (PsP) from multiparametric MRI-based prediction model using histopathology/mRANO criteria as ground truth. Multiparametric MRI model consisted of predictive probabilities (PP) of tumor progression computed from diffusion and perfusion MRI-derived parameters. A comparison of overall survival (OS) was performed between patients treated with standard-of-care therapy + DCVax-L and standard-of-care therapy alone (external controls). Additionally, Kaplan-Meier analyses were performed to compare OS between two groups of patients using PsP, Ki-67, and MGMT promoter methylation status as stratification variables. RESULTS: Multiparametric MRI model correctly predicted TP + mixed response in 72.7% of cases (8/11) and PsP in 83.3% (5/6) with an overall concordance rate of 76.5% with final diagnosis as determined by histopathology/mRANO criteria. There was a significant concordant correlation coefficient between PP values and histopathology/mRANO criteria (r = 0.54; p = 0.026). DCVax-L-treated patients had significantly prolonged OS than those treated with standard-of-care therapy (22.38 ± 12.8 vs. 13.8 ± 9.5 months, p = 0.040). Additionally, glioblastomas with PsP, MGMT promoter methylation status, and Ki-67 values below median had longer OS than their counterparts. CONCLUSION: Multiparametric MRI-based prediction model can assess treatment response to DCVax-L in patients with glioblastoma.

Economic impact of selective use of contrast for routine follow-up MRI of patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Imaging and autopsy studies show intracranial gadolinium deposition in patients who have undergone serial contrast-enhanced MRIs. This observation has raised concerns when using contrast administration in patients who receive frequent MRIs. To address this, we implemented a contrast-conditional protocol wherein gadolinium is administered only for multiple sclerosis (MS) patients with imaging evidence of new disease activity on precontrast imaging. In this study, we explore the economic impact of our new MRI protocol. METHODS: We compared scanner time and Medicare reimbursement using our contrast-conditional methodology versus that of prior protocols where all patients received gadolinium. RESULTS: For 422 patients over 4 months, the contrast-conditional protocol amounted to 60% decrease in contrast injection and savings of approximately 20% of MRI scanner time. If the extra scanner time was used for performing MS follow-up MRIs in additional patients, the contrast-conditional protocol would amount to net revenue loss of $21,707 (∼3.7%). CONCLUSIONS: Implementation of a new protocol to limit contrast in MS follow-up MRIs led to a minimal decrease in revenue when controlled for scanner time utilized and is outweighed by other benefits, including substantial decreased gadolinium administration, increased patient comfort, and increased availability of scanner time, which depending on type of studies performed could result in additional financial benefit.

The diagnostic and economic yield of neuroimaging in neuro-ophthalmology.

BACKGROUND: Diagnostic studies such as computed tomography scans (CT) and magnetic resonance imaging (MRI) are ordered frequently in neuro-ophthalmic practice, although the diagnostic yield and cost-effectiveness of these tests have been studied for only a few conditions. We assessed the diagnostic and economic yield of CT and MRI across all patients evaluated in a neuro-ophthalmology practice. METHODS: This retrospective review included all patients referred by the division of neuro-ophthalmology at the Scheie Eye Institute for CT, CT angiography, MRI, MRA, or magnetic resonance venography over a 12-month period. Abnormal imaging findings were categorized as significant (one that elicited changes in management) and/or relevant (one that related to the patient's neuro-ophthalmic complaint or examination findings). The diagnostic yield of the test ordered was analyzed according to the patient's chief complaint, neuro-ophthalmic examination findings, and indication for imaging. The total costs for each diagnostic group and costs per significant finding were calculated using the global Resource-Based Relative Value Units for each examination from the Centers for Medicare and Medicaid Services Web site. RESULTS: Two hundred eleven imaging studies in 157 patients were evaluated. 28.9% (95% confidence interval, 22.5%-36.2%) of imaging studies had significant abnormalities relevant to the neuro-ophthalmic complaint. Imaging obtained for evaluation of progressive optic nerve dysfunction and cranial nerve palsy had statistically significant higher diagnostic yield than studies performed for other reasons. Total cost of all imaging studies performed was $107,615.72. Cost per clinically significant and relevant finding was $1,764.19. CONCLUSIONS: In comparison to the diagnostic yield of neuroimaging studies in other specialties, CT and MRI of the brain requested by neuro-ophthalmologists provide significant and relevant data at a reasonable cost.

CT-guided aspirations in the head and neck: assessment of the first 216 cases.

BACKGROUND AND PURPOSE: The growth of cross-sectional imaging has increased the detection of nonpalpable head and neck masses. We sought to determine the reliability of CT-guided fine-needle aspiration (FNA) over 216 consecutive cases. METHODS: We retrospectively reviewed histopathologic findings and notes from 216 consecutive head and neck CT-guided FNA procedures performed between 1993 and 2003. Types of needles used, passes required, lesion location, initial cytologic diagnosis, and final histopathologic or clinical diagnosis were reviewed. RESULTS: Diagnostic samples were obtained in 195 (90.3%) of the lesions, with 21 (9.7%) inadequate samples. A correct diagnosis was made in 191 cases (88.4%). Final FNA diagnosis was discordant in four (1.9%) specimens, with the parapharyngeal space and parotid gland having the highest rate of inaccuracy. The range in number of passes required for final diagnosis was one to six (mode, 2.0 passes per specimen; median, 2.0; mean, 2.6; standard deviation, 1.13). In 135 (63%) of 216 cases, definitive surgical pathologic results, including findings for the four discordant specimens, were obtained. Of the nondiagnostic specimens, six (29%) of 21 went to surgery, five (83%) of six were neoplastic, and one (17%) of six was fibrous tissue. The remainder underwent clinical and imaging follow-up. CONCLUSION: CT-guided FNA is a safe, well tolerated, and accurate for the diagnosis of head and neck lesions. In our series, the percentage of diagnostic samples obtained improved compared with prior reports. The low diagnostic error rate overall was possibly related to onsite evaluation by the cytopathologist and to improved FNA technique.