Alexander J. Nemeth

Blood Pressure Reduction, Decreased Diffusion on MRI, and Outcomes After Intracerebral Hemorrhage

Background and Purpose— Decreased diffusion (DD) consistent with acute ischemia may be detected on MRI after acute intracerebral hemorrhage (ICH), but its risk factors and impact on functional outcomes are not well-defined. We tested the hypotheses that DD after ICH is related to acute blood pressure (BP) reduction and lower hemoglobin and presages worse functional outcomes. Methods— Patients who underwent MRI were prospectively evaluated for DD by certified neuroradiologists blinded to outcomes. Hemoglobin and BP data were obtained via electronic queries. Outcomes were obtained at 14 days and 3 months with the modified Rankin Scale, a functional scale scored from 0 (no symptoms) to 6 (dead). We used logistic regression for dependence or death (modified Rankin Scale score 4–6). Results— DD distinct from the hematoma was found on MRI in 39 of 95 patients (41%). DD was associated with greater BP reductions from baseline and a higher risk of dependence or death at 3 months (odds ratio, 4.8; 95% confidence interval, 1.7–13.9; P=0.004) after correction for ICH score (1.8 per point; 95% confidence interval, 1.2–3.1; P=0.01). Lower hemoglobin was associated with worse ICH score, larger hematoma volume, and worse outcomes, but not DD. Conclusions— DD is common after ICH, associated with greater acute BP reductions, and associated with disability and death at 3 months in multivariate analysis. The potential benefits of acute BP reduction to reduce hematoma growth may be limited by DD. The prevention and treatment of cerebral ischemia manifested as DD are potential methods to improve outcomes.

Improved Detection of Skull Metastasis with Diffusion-Weighted MR Imaging

BACKGROUND AND PURPOSE: Metastasis to the skull is clinically important, but routine MR imaging offers moderate sensitivity for skull-metastasis detection in our experience. We sought to determine if diffusion-weighted MR imaging (DWI) could improve the detection of skull metastasis in patients with primary carcinomas that metastasized to bone compared with conventional MR imaging. MATERIALS AND METHODS: Seventy-five patients from the tumor registry of our institution with extracranial primary malignancy who had brain MR imaging with DWI and radionuclide bone scanning (RNBS, gold standard) within a 6-week interval were evaluated. Thirty-eight patients demonstrated increased radiopharmaceutical uptake on RNBS, consistent with skull metastasis of any size, and the remaining 37 were control subjects. Two readers correlated the DWI and conventional MR imaging with RNBS. RESULTS: The overall sensitivity of DWI for detection of skull metastases was 68.4%–71.1% (κ = 0.68) versus 42.1%–55.3% (κ = 0.65) for conventional MR imaging. Breast cancer (n = 20) was detected with greatest sensitivity of 86.7%–93.3% (κ = 0.80) for DWI versus 60%–80% (κ = 0.5) for conventional MR imaging. Lung cancer (n = 32) was detected with 63.6%–72.7% sensitivity (κ = 0.56), and prostate cancer (n = 8) with 14.3% sensitivity (κ = 0.5) for DWI versus 27.3%–36.4% (κ = 0.81) and 14.3–42.9% (κ = 0), respectively, for conventional MR imaging. CONCLUSIONS: DWI is a useful sequence for identifying focal skull metastases for breast and lung malignancies and, compared with conventional MR imaging, provides improved detection of these lesions. DWI is insensitive for detecting skull metastases from prostate carcinoma.

Delayed intraventricular hemorrhage is common and worsens outcomes in intracerebral hemorrhage

Objective: To evaluate the incidence, characteristics, and clinical consequences of delayed intraventricular hemorrhage (dIVH). Methods: Patients with primary intracerebral hemorrhage (ICH) were enrolled into a prospective registry between December 2006 and February 2012. Patients were managed, and serial neuroimaging obtained, per a structured protocol. Initial and delayed IVH were identified on imaging, along with ICH volumes, with outcomes blinded. Multivariate models were developed to test whether the occurrence of dIVH was a predictor of functional outcomes independent of known predictors, including the ICH score elements and ICH growth. Results: A total of 216 patients were studied, and 104 (48%) had IVH on initial imaging. Of the 112 with no IVH, 23 (21%) subsequently developed IVH. Emergent surgical intervention, mostly ventriculostomy placement, was required after discovery of dIVH in 10 (43%) of these 23. In multivariate models adjusting for all elements of the ICH score and hematoma growth, dIVH was an independent predictor of death at 14 days (p = 0.015) and higher modified Rankin Scale scores at 3 months (all p = 0.037). The effect of dIVH remained significant in a secondary analysis that adjusted for all other variables significant in the univariate analysis. Conclusions: Similar to hematoma expansion dIVH is independently associated with death and poor outcomes. Because IVH is easily detected by serial neuroimaging and often requires emergent surgical intervention, monitoring for dIVH is recommended.

Meigs syndrome revisited

The association of a benign ovarian tumor with ascites and hydrothorax that resolve after tumor resection is known as Meigs syndrome, and its importance was first emphasized by Meigs and Cass in 1937. The importance of Meigs syndrome is that the presence of ascites and pleural effusion does not necessarily indicate that a pelvic mass is malignant. The benign tumors in Meigs syndrome are usually fibromas or fibrothecomas and constitute 4% of all ovarian neoplasms. The authors present a case of Meigs syndrome with an ovarian fibroma. They focus on the evaluation of pleural fluid in the setting of an ovarian mass and then briefly discuss the imaging of ovarian fibromas and fibrothecomas.

Predictors of hemorrhage volume and disability after perimesencephalic subarachnoid hemorrhage

Objective: The determinants of subarachnoid hemorrhage (SAH) volume and an atypical pattern of blood are not clear. Our objective was to determine if reduced platelet activity on admission and abnormal venous drainage are associated with greater SAH volume. Methods: We prospectively identified noncomatose patients with SAH without an identifiable aneurysm. We routinely measured platelet activity on admission and recorded aspirin use. SAH volumes were calculated with a validated technique. CT angiograms were reviewed by a certified neuroradiologist for venous drainage. Patients were followed for clinical outcomes through 3 months with the modified Rankin Scale (mRS). Data are Q1–Q3. Results: There were 31 patients in the cohort. Thirty (97%) underwent an angiogram on admission, and 25 (81%) an additional delayed angiogram. SAH volume was lowest with normal venous drainage bilaterally (4.4 [3.7–16.4] mL) and higher with 1 (12.9 [3.7–20.4]) or 2 (20.9 [12.5–34.6] mL, p = 0.03) discontinuous venous drainages. Patients with reduced platelet activity had more SAH on the diagnostic CT (17.5 [10.6–20.9] vs 6.1 [2.3–15.3] mL) (p = 0.046). SAH volume was greater for patients requiring drainage for hydrocephalus (16.4 [11.5–20.5] vs 5.4 [2.7–16.4] mL) (p = 0.009). Outcomes at 3 months were generally excellent (median mRS = 0, no symptoms). Conclusions: Discontinuous venous drainage and reduced platelet activity were associated with increased SAH volume and hydrocephalus. These factors may explain thick SAH and reduce the need for repeated invasive imaging in such patients.

An Introduction to the Fourier Transform: Relationship to MRI

OBJECTIVE The Fourier transform, a fundamental mathematic tool widely used in signal analysis, is ubiquitous in radiology and integral to modern MR image formation. Understanding MRI techniques requires a basic understanding of what the Fourier transform accomplishes. MR image encoding, filling of k-space, and a wide spectrum of artifacts are all rooted in the Fourier transform. CONCLUSION This article illustrates these basic Fourier principles and their relationship to MRI.

Placebo-Controlled Trial of Familiar Auditory Sensory Training for Acute Severe Traumatic Brain Injury: A Preliminary Report

Background. Sensory stimulation is often provided to persons incurring severe traumatic brain injury (TBI), but therapeutic effects are unclear. Objective. This preliminary study investigated neurobehavioral and neurophysiological effects related to sensory stimulation on global neurobehavioral functioning, arousal, and awareness. Methods. A double-blind randomized placebo-controlled trial where 15 participants in states of disordered consciousness (DOC), an average of 70 days after TBI, were provided either the Familiar Auditory Sensory Training (FAST) or Placebo of silence. Global neurobehavioral functioning was measured with the Disorders of Consciousness Scale (DOCS). Arousal and awareness were measured with the Coma-Near-Coma (CNC) scale. Neurophysiological effect was measured using functional magnetic resonance imaging (fMRI). Results. FAST (n = 8) and Placebo (n = 7) groups each showed neurobehavioral improvement. Mean DOCS change (FAST = 13.5, SD = 8.2; Placebo = 18.9, SD = 15.6) was not different, but FAST patients had significantly (P = .049; 95% confidence interval [CI] = −1.51, −.005) more CNC gains (FAST = 1.01, SD = 0.60; Placebo = 0.25, SD = 0.70). Mixed-effects models confirm CNC findings (P = .002). Treatment effect, based on CNC, is large (d = 1.88, 95% CI = 0.77, 3.00). Number needed to treat is 2. FAST patients had more fMRI activation in language regions and whole brain (P values <.05) resembling healthy controls’ activation. Conclusions. For persons with DOC 29 to 170 days after TBI, FAST resulted in CNC gains and increased neural responsivity to vocal stimuli in language regions. Clinicians should consider providing the FAST to support patient engagement in neurorehabilitation.

Subarachnoid Extension of Primary Intracerebral Hemorrhage is Associated With Poor Outcomes

Background and Purpose— Extension of hemorrhage into the subarachnoid space is observed in primary intracerebral hemorrhage (ICH), yet the phenomenon has undergone limited study and is of unknown significance. The objective of this study is to evaluate the incidence, characteristics, and clinical consequences of subarachnoid hemorrhage extension (SAHE) in ICH on functional outcomes. Methods— Patients with primary ICH were enrolled into a prospective registry between December 2006 and June 2012. Patients were managed and serial neuroimaging was obtained per a structured protocol. Presence of any subarachnoid blood on imaging was identified as SAHE by expert reviewers blinded to outcomes. Regression models were developed to test whether the occurrence of SAHE was an independent predictor of functional outcomes as measured with the modified Rankin Scale. Results— Of 234 patients with ICH, 93 (39.7%) had SAHE. Interrater agreement for SAHE was excellent (kappa=0.991). SAHE was associated with lobar hemorrhage location (65% of SAHE vs 19% of non-SAHE cases; P<0.001) and larger hematoma volumes (median 23.8 vs 6.7; P<0.001). Fever (69.9% vs 51.1%; P=0.005) and seizures (8.6% vs 2.8%; P=0.07) were more common in patients with SAHE. SAHE was a predictor of death by day 14 (odds ratio, 4.45; 95% confidence interval, 1.88–10.53; P=0.001) and of higher (worse) modified Rankin Scale scores at 28 days (odds ratio, 1.76 per mRS point; 95% confidence interval, 1.01–3.05; P=0.012) after adjustment for ICH score. Conclusions— SAHE is associated with worse modified Rankin Scale independent of traditional ICH severity measures. Underlying mechanisms and potential treatments of SAHE require further study.

Posterior reversible encephalopathy syndrome and venous thrombosis

Posterior reversible encephalopathy syndrome (PRES) and venous thrombosis are frequently encountered first in the emergency setting and share some common characteristics. The clinical presentation in both entities is vague, and the brain parenchymal findings of PRES syndrome may resemble those of venous thrombosis in some ways. Both entities often occur in a bilateral posterior distribution and may be associated with reversible parenchymal findings if the inciting factor is treated. These diagnoses should be at the forefront of the differential diagnosis when confronted with otherwise unexplained brain edema, among other findings described in this article.

Magnetic resonance imaging versus computed tomography for identification and quantification of intraventricular hemorrhage.

BACKGROUND Intraventricular hemorrhage (IVH) may be difficult to detect especially when in small amounts and may affect outcomes. The objective of this study was to compare the sensitivity of magnetic resonance imaging (MRI) vs computed tomography (CT) for the identification and quantification of IVH. METHODS Patients with primary intracerebral hemorrhage were enrolled into a prospective registry between December 2006 and June 2013. Diagnostic and surveillance neuroimaging studies were analyzed for the presence of IVH and quantified by Graeb score. In subjects who developed IVH and underwent both MRI and CT, each MRI was paired with the CT scan done at the closest time point, and Graeb scores were compared with the Wilcoxon signed rank test for related samples. RESULTS There were 289 subjects in the cohort with IVH found in 171. Sixty-eight pairs of MRI and CT were available for comparison. CT failed to detect IVH in 3% of cases, whereas MRI was 100% sensitive. MRI and CT yielded equal Graeb scores in 72% of the pairs, and MRI Graeb score was higher in 24% (P = .007). CONCLUSIONS MRI identifies small volumes of IVH in cases not detected by CT and yields higher estimates of intraventricular blood volume. These data indicate that consideration of technical differences is needed when comparing images from the 2 modalities in the evaluation for IVH.