Invasive Pulmonary Adenocarcinomas Versus Preinvasive Lesions Appearing as Pure Ground-Glass Nodules: Differentiation Using Enhanced Dual-Source Dual-Energy CT.

OBJECTIVE. The objective of our study was to investigate the potentials of enhanced dual-source dual-energy CT (DECT) and three-planar measurements for differentiating invasive pulmonary adenocarcinomas (IPAs) from preinvasive lesions appearing as pure ground-glass nodules (pGGNs). MATERIALS AND METHODS. Thirty-nine patients with 53 pGGNs who underwent enhanced dual-source DECT were included in this retrospective study. All pGGNs were pathologically confirmed and categorized into two groups: preinvasive lesions or IPAs. The traditional CT features of the pGGNs were evaluated on unenhanced images. Quantitative parameters were measured on iodine-enhanced images of dual-source DECT in three planes, and both intra- and interobserver reproducibility analyses were performed to assess the measurement reproducibility of quantitative parameters. To identify significant factors for differentiating IPAs from preinvasive lesions, we performed logistic regression analysis and ROC curve analysis. RESULTS. For traditional CT features, only lesion size and unenhanced CT attenuation value showed significant differences between preinvasive lesions and IPAs (p < 0.05). Preinvasive lesions and IPAs exhibited significant differences in attenuation on virtual images, so-called "virtual HU" or "VHU," and the modified normalized iodine concentration (NIC) (p < 0.05), and both intra- and interobserver agreement for the quantitative measurements were excellent. Multivariate logistic regression analysis revealed that larger lesion size (adjusted odds ratio [OR], 3.65) and higher modified NIC (adjusted OR, 19.01) were significant differentiators of IPAs from preinvasive lesions (p < 0.05). ROC curve analysis revealed that modified NIC showed excellent performance (AUC, 0.924) and significantly higher performance than lesion size (AUC, 0.711) for differentiating IPAs from preinvasive lesions. CONCLUSION. In pGGNs, a lesion with a modified NIC value of more than 0.29 can be a very specific discriminator of IPAs from preinvasive lesions, and IPAs can be accurately and reliably differentiated from preinvasive lesions using enhanced dual-source DECT and three-planar measurements.

Brain iron deposition analysis using susceptibility weighted imaging and its association with body iron level in patients with mild cognitive impairment.

The aim of the present study was to analyze brain and body iron levels among patients with mild cognitive impairment (MCI), Alzheimer's disease (AD), and normal controls (NCs). A total of 90 participants (30 MCI, 30 AD, 30 NC) were enrolled. Brain iron content was quantified using susceptibility weighted imaging (SWI). Phase values were used to calculate bilateral iron content in the hippocampus (HP), substantia nigra, red nucleus (RN), dentate nucleus (DN), caudate nucleus (CN), globus pallidus (GP), putamen (PUT), frontal white matter, temporal cortex (TC), and parietal cortex. Body iron indices, including serum iron, serum transferrin, ferritin and total iron binding capacity, were measured. Phase values of the left (L)­DN, L­CN, and bilateral PUT in the MCI group were significantly lower compared with NC group. Phase values of the right (R)­RN, bilateral DN, and bilateral PUT in the AD group were significantly lower compared with the MCI group. Phase values of the bilateral HP, DN, RN, CN, GP, PUT, and L­TC in the AD group were significantly lower compared with the NC group. Serum ferritin levels in the MCI and AD groups were significantly lower compared with the NC group. Only serum iron in the AD group was positively associated with iron content in the R­HP. Brain iron deposition and body iron levels both increased in MCI and AD patients, however, excessive brain iron accumulation may have no association with body iron level. SWI was particularly effective at recognizing the presence of brain iron in the MCI and AD groups.

A perfusion-metabolic mismatch in Sturge-Weber syndrome: a multimodality imaging study.

OBJECTIVE: We combined perfusion weighted imaging (PWI) with 2-deoxy-2[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET) to study the relationship between regional metabolic and perfusion abnormalities and their clinical correlates in children with Sturge-Weber syndrome (SWS). METHODS: Fifteen children (age: 0.9-10 years) with unilateral SWS underwent high-resolution PWI and FDG PET prospectively. Regional (lobar) asymmetry indices (AIs) of subcortical white matter (WM) cerebral blood flow (CBF) were correlated with corresponding cortical FDG uptake asymmetries, extent of leptomeningeal vascular malformation and clinical seizure variables. RESULTS: Abnormal cortical glucose metabolism and/or subcortical WM CBF were seen in all lobes affected by vascular malformation and extended to lobes not affected by abnormal pial vessels in 6 patients. Lower CBF was associated with lower cortical glucose metabolism in the temporal, parietal and occipital lobes (p≤0.02). While decreased perfusion was associated with hypometabolism in most cases, increased regional CBF (found in 6 patients) was commonly associated with relatively mild or no hypometabolism. Ten of 24 cerebral lobes with normal glucose metabolism in the affected hemisphere showed abnormal perfusion. High seizure frequency was associated with severe parieto-occipital hypoperfusion (p≤0.03), while long duration of epilepsy was related to frontal lobe hypometabolism (p=0.015). CONCLUSIONS: Regional perfusion and cortical metabolic abnormalities can extend beyond lobes affected by leptomeningeal vascular malformations and are related to epilepsy in SWS. Despite a general correlation between perfusion and metabolism, increased WM perfusion with preserved cortical metabolism in overlying cortex is a common pattern of a perfusion/metabolic mismatch. This may represent a disease stage where cortical function is preserved while increased WM perfusion provides collateral drainage of cortex via the deep vein system.

Cortical calcification in Sturge-Weber Syndrome on MRI-SWI: relation to brain perfusion status and seizure severity.

PURPOSE: To determine the relationship between calcified cortex and perfusion status of white matter and seizure severity in patients with Sturge-Weber Syndrome (SWS), a sporadic neurocutaneous disorder characterized by a leptomeningeal angioma, progressive brain ischemia, and a high incidence of seizures using susceptibility weighted imaging (SWI) and dynamic susceptibility contrast-enhanced perfusion weighted imaging (DSC-PWI). MATERIALS AND METHODS: Fifteen children (ages: 0.9-10 years) with unilateral SWS prospectively underwent magnetic resonance imaging (MRI). The degree of cortical calcification was assessed using SWI while perfusion status was quantified using DSC-PWI images (asymmetries of various perfusion parameters). Comparisons between calcification, perfusion status, and seizure variables were performed. RESULTS: Patients with severely calcified cortex demonstrated significantly lower perfusion in the ipsilateral white matter (mean asymmetry: -0.52 ± 0.22) as compared to patients with only mildly calcified cortex or no calcification (mean asymmetry: 0.08 ± 0.25). Patients with severely calcified cortex also suffered from a higher seizure burden (a composite measure of seizure frequency and epilepsy duration; P = 0.01) and a trend for earlier seizure onset and longer epilepsy duration. CONCLUSION: Severe calcification in the affected hemisphere is related to severely decreased perfusion in underlying white matter and is associated with more severe epilepsy in SWS patients.