Michele Gaeta

Computed tomography halo sign in pulmonary nodules: frequency and diagnostic value.

On computed tomography (CT) scanning, a ground-glass opacity zone surrounding a pulmonary nodule has been named the computed tomography (CT) halo sign. To investigate the frequency and diagnostic value of the CT halo sign, the authors reviewed the CT examinations of 305 patients with proven diseases producing solitary or multiple nodules. The CT halo sign was seen in 22 patients (7%). Eleven patients had a solitary nodule; five patients had multiple nodules; and six patients had nodules associated with areas of pulmonary consolidation, or ground-glass opacity, or both. Solitary nodules were the result of bronchioloalveolar carcinoma (n = 5), tuberculoma (n = 2), squamous cell carcinoma, non-Hodgkin lymphoma, myxovirus infection, and metastasis (n = 1 each). Multiple nodules were the result of metastasis (n = 2), Kaposi sarcoma (n = 2), and Wegener granulomatosis (n = 1). Nodules associated with areas of consolidation or ground-glass opacity were the result of metastasis (n = 2), bronchioloalveolar carcinoma, bronchiolitis obliterans organizing pneumonia, eosinophilic pneumonia, and invasive pulmonary aspergillosis (n = 1 each). The data showed that the CT halo sign is a nonspecific finding. It is known that in immunocompromised patients the CT halo sign should suggest invasive pulmonary aspergillosis, Kaposi sarcoma, and lymphoproliferative pulmonary disorders. However, in immunocompetent patients, the authors found that a solitary nodule with the CT halo sign and pseudocavitations has a high likelihood of being a bronchioloalveolar carcinoma.

Muscle Fat Fraction in Neuromuscular Disorders: Dual-Echo Dual-Flip-Angle Spoiled Gradient-Recalled MR Imaging Technique for Quantification—A Feasibility Study

PURPOSE To prospectively evaluate the muscle fat fraction (MFF) measured with dual-echo dual-flip-angle spoiled gradient-recalled acquisition in the steady state (SPGR) magnetic resonance (MR) imaging technique by using muscle biopsy as the reference standard. MATERIALS AND METHODS After ethics approval, written informed consent from all patients was obtained. Twenty-seven consecutive patients, evaluated at the Neuromuscular Disorders Center with a possible diagnosis of neuromuscular disorder, were prospectively studied with MR imaging of the lower extremities to quantify muscle fatty infiltration by means of MFF calculation. Spin-density- and T1-weighted fast SPGR in-phase and opposed-phase dual-echo sequences were performed, respectively, with 20° and 80° flip angles. Round regions of interest were drawn by consensus on selected MR sections corresponding to anticipated biopsy sites. These were marked on the patients skin with a pen by using the infrared spider light of the system, and subsequent muscle biopsy was performed. MR images with regions of interest were stored on a secondary console where the MFF calculation was performed by another radiologist blinded to the biopsy results. MFFs calculated with dual-echo dual-flip-angle SPGR MR imaging and biopsy were compared by using a paired t test, Pearson correlation coefficient, and Bland-Altman plots. P value of < .05 was considered to indicate a statistically significant difference. RESULTS The mean MFFs obtained with dual-echo dual-flip-angle SPGR MR imaging and biopsy were 20.3% (range, 1.7%-45.1%) and 20.6% (range, 3%-46.1%), respectively. The mean difference, standard deviation of the difference, and t value were -0.3, 1.3, and -1.3 (P > .2), respectively. The Pearson correlation coefficient was 0.995; with the Bland-Altman method, all data points were within the ± 2 SDs limits of agreement. CONCLUSION The results show that dual-echo dual-flip-angle SPGR MR imaging technique provides reliable calculation of MFF, consistent with biopsy measurements.

Contrast-enhanced MR imaging with fat suppression in adult-onset septic spondylodiscitis.

Abstract. Spinal infections typically involve vertebrae as well as discs, and for this reason they are called septic spondylodiscitis. Magnetic resonance imaging is the most sensitive imaging method for the evaluation of this group of spinal diseases. The use of contrast-enhanced T1-weighted sequences with fat suppression, if correctly applied, may increase information provided by MRI. Firstly, this technique allows the primary vertebral focus, which often precedes disc involvement, to be identified at a very early stage. When the disease spreads, T1-weighted fat-suppressed gadolinium dimeglumine (Gd-DTPA) enhanced images provide macroscopic details of the primary vertebral focus, disc involvement patterns, and pathways of infection diffusion. All this information, when correlated with laboratory tests, may be useful in identifying the infectious agents (tuberculous vs piogenic forms), thus enabling a suitable therapy to be started. This technique is also useful in the assessment of the real extension of the disease, providing a clear depiction of paravertebral space involvement and of psoas muscle abscesses. Dangerous complications, such as meningitis, myelitis, and epidural abscesses, may be more promptly diagnosed and fully evaluated with fat-suppressed post-contrast T1-weighted images. Finally, this imaging technique may help to differentiate infectious processes from degenerative disorders, extradural neoplastic processes, and rheumatic diseases.

Cortical and Subcortical Connections of the Human Claustrum Revealed In Vivo by Constrained Spherical Deconvolution Tractography

The claustrum is a thin layer of gray matter that is at the center of an active scientific debate. Recently, Constrained Spherical Deconvolution (CSD) tractography has proved to be an extraordinary tool allowing to track white matter fibers from cortex to cortical and subcortical targets with subvoxel resolution. The aim of this study was to evaluate claustral connectivity in the human brain. Ten normal brains were analyzed by using the High Angular Resolution Diffusion Imaging CSD-based technique. Tractography revealed 4 groups of white matter fibers connecting the claustrum with the brain cortex: Anterior, posterior, superior, and lateral. The anterior and posterior cortico-claustral tracts connected the claustrum to prefrontal cortex and visual areas. The superior tract linked the claustrum with sensory-motor areas, while the lateral pathway connected the claustrum to the auditory cortex. In addition, we demonstrated a claustral medial pathway connecting the claustrum with the basal ganglia, specifically with caudate nucleus, putamen, and globus pallidus. An interesting and exciting new finding was the demonstration of a bilateral connection between claustrum and contralateral cortical areas and a well-represented interclaustral communication with interconnection bundles interspersed within the bulk of the trunk of the corpus callosum. The physiological and pathophysiological relevance of these findings are discussed.

Dual-Source Dual-Energy CT Evaluation of Complex Cystic Renal Masses

OBJECTIVE The purpose of this study was to assess the value of dual-source dual-energy CT in the evaluation of complex cystic renal masses. SUBJECTS AND METHODS Seventy patients underwent contrast-enhanced dual-energy CT that included true unenhanced images acquired in single-energy mode, corticomedullary phase images acquired in dual-energy mode, and nephrographic phase images acquired in single-energy mode. Virtual unenhanced, blended weighted-average, and color-coded iodine overlay images were reconstructed. The acceptance level and image quality of virtual and true unenhanced images were evaluated. Contrast enhancement on both true unenhanced or blended weighted-average images and color-coded iodine overlay images was evaluated with both calculation in regions of interest and use of confidence level scales. Radiation dose parameters were estimated. RESULTS Virtual unenhanced images of 70 lesions (97.2%) and true unenhanced images of 72 lesions (100%) were judged acceptable (p = 0.5). The mean quality score of virtual unenhanced images was 2.0 ± 0.7 and of true unenhanced images was 1.5 ± 0.5 (p < 0.001). Mean contrast enhancement measured on true unenhanced and blended weighted-average images was 45.9 ± 15.9 HU (range, 21-78 HU) and on color-coded iodine overlay images was 47.3 ± 16.8 HU (range, 22-75 HU) with no significant differences. Enhancement was excluded on color-coded iodine overlay images with a significantly (p < 0.03) higher level of confidence than it was on true unenhanced and blended weighted-average images. The mean dose reduction with use of a combined dual- and single-energy dual-phase CT protocol was 29.1% ± 11.9% (p < 0.001). CONCLUSION Dual-source dual-energy CT is a reliable imaging technique in the evaluation of complex cystic renal masses. True unenhanced images can be replaced by virtual unenhanced images with considerable radiation dose reduction. The color-coded iodine overlay technique is a useful tool for both excluding and identifying endocystic enhancement.

MRI of Cardiac Involvement in Transthyretin Familial Amyloid Polyneuropathy

OBJECTIVE The purpose of this study was to evaluate cardiac MRI features in a group of patients with transthyretin familial amyloid polyneuropathy (FAP). SUBJECTS AND METHODS Sixteen patients with transthyretin FAP underwent 2D echocardiography with Doppler examination, cardiac MRI, and (99m)Tc-diphosphonate (DPD) scintigraphy. Four patients had peripheral polyneuropathy, three had carpal tunnel syndrome, one patient had symptoms and signs of heart failure, and eight patients had no symptoms but had a family history of FAP. At MRI, cardiac function parameters and delayed contrast enhancement findings were evaluated. RESULTS Six patients had cardiac radiotracer uptake at scintigraphy (FAP cardiac group), and 10 patients had no cardiac uptake (FAP noncardiac group). The FAP cardiac group included the four patients with peripheral neuropathy, one patient with carpal tunnel syndrome, and the only patient with heart failure. At MRI, abnormal contrast enhancement was found in all patients with positive scintigraphic findings and in no patient with negative scintigraphic findings. All patients had involvement of the left ventricle and other chambers or structures (atria, right ventricle, tricuspid valve leaflets). Left ventricular contrast enhancement was focal in four patients, subendocardial circumferential in one patient, and diffuse in one patient. The only patient with signs of heart failure had circumferential subendocardial enhancement. CONCLUSION Cardiac contrast-enhanced MRI can be used to identify cardiac amyloidosis in patients with FAP who do not have clinical signs of heart involvement. In these patients, the typical subendocardial circumferential pattern of contrast enhancement is rare. We observed unusual enhancement patterns as focal or diffuse left ventricular enhancement accompanied by enhancement of the atria, tricuspid valve, or right ventricle.

High-Resolution CT Grading of Tibial Stress Reactions in Distance Runners

OBJECTIVE The purpose of this study was twofold: to determine whether asymptomatic distance runners exhibit cortical tibial abnormalities on CT and to determine the diagnostic accuracy of CT in athletes with medial tibial stress syndrome. MATERIALS AND METHODS A cross-sectional study with high-resolution CT of both tibiae was performed on 41 subjects: 20 asymptomatic distance runners, 11 distance runners with unilateral or bilateral pain due to medial tibial stress syndrome (14 painful tibiae), and 10 volunteers not involved in a sport. The group was composed of 13 women and 28 men, ranging in age from 18 to 26 years. A total of 82 tibiae, 14 painful and 68 painless, were evaluated. On the basis of CT findings, tibiae were classified in three groups, and correlation between CT classification and symptoms was made. RESULTS Among distance runners, the presence of CT abnormalities was found in 14 (100%) of 14 painful tibiae in patients with medial tibial stress syndrome and in 8 (16.6%) of 48 painless tibiae. The difference was statistically significant (p < 0.001, Fishers exact test). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT in diagnosing medial tibial stress syndrome were 100%, 88.2%, 63.6%, 100%, and 90.2%, respectively. CONCLUSION High-resolution CT has high diagnostic accuracy in depicting medial tibial stress syndrome. Cortical abnormalities can also be seen in some asymptomatic distance runners.

Usefulness of power Doppler and contrast-enhanced sonography in the differentiation of hyperechoic renal masses

AbstractBackground: In a prospective study, we compared power Doppler with and without contrast medium in the depiction of vascularity for the characterization of hyperechoic renal lesions. Methods: Forty-one hyperechoic renal expansive lesions (29 benign, 12 malignant) in 32 patients were studied with power-Doppler ultrasonography before and after administration of an echo-enhancing agent (Levovist Schering AG, Berlin, Germany). Vascular architecture of the lesions was categorized into five different patterns. Results: Power Doppler ultrasonography showed vascular structures in 25 lesions. The study enhanced with Levovist showed vascularity in eight of 16 lesions not seen on the unenhanced study. The characterization of vascular patterns with unenhanced power Doppler ultrasonography improved diagnostic accuracy compared with gray-scale ultrasonography (59% vs. 32%). The combination of B mode and power Doppler produced even greater diagnostic accuracy (78%), independent of the administration of echo-enhancing agent. Levovist administration was useful in the differential diagnosis between pseudotumor and neoplasm. Conclusion: The use of songraphic contrast agent did not increase the diagnostic accuracy of power Doppler in the differential diagnosis of hyperechoic renal lesions but was advantageous for the characterization of suspected pseudomasses.

Patterns of recurrence of bronchioloalveolar cell carcinoma after surgical resection: a radiological, histological, and immunohistochemical study.

PURPOSE Bronchioloalveolar carcinoma (BAC) is a subtype of lung adenocarcinoma whose incidence is raising. Bronchioloalveolar carcinoma has a tendency to involve diffusely the lung. No agreement exists about whether diffuse bronchioloalveolar carcinoma has a multicentric or unicentric origin. The purpose of this work is to evaluate the correlation between intrapulmonary spread of bronchioloalveolar carcinoma and its histologic and immunohistochemical characteristics. DESIGN Surgical specimens of 20 bronchioloalveolar carcinomas with radiologically proved evolution from focal to diffuse disease were retrieved and reviewed. Patterns of pulmonary spread were defined on the basis of CT and MR imaging examinations. Immunohistochemical studies were performed to investigate the expression of gelatinase A and alpha2-integrin. Correlation between immunohistochemical results and patterns of pulmonary spread was evaluated. Statistical evaluation was performed by using Fisher Exact Test. RESULTS Three histological subtypes of bronchioloalveolar carcinoma were found: mucinous (11 cases), non-mucinous (3 cases), and mixed adenocarcinoma with prominent bronchioloalveolar pattern (6 cases). Three patterns of pulmonary spread were depicted radiologically: parenchymal opacification (11 cases), multiple nodules (7 cases) and mixed pattern (2 cases). Eleven out of 12 mucin-producing versus none out of 8 non-mucin producing cancers developed parenchymal opacification. The difference was statistically significant (P<0.028). A statistically significant difference was also found between the development of parenchymal opacification and the level of alpha2-integrin: 11 out of 13 tumors with negative alpha2-integrin versus none out of 7 with positive alpha2-integrin immunoreactivity (P>0.033). CONCLUSIONS Diffuse bronchioloalveolar carcinoma may develop from a prior focal cancer. Mucinous subtype is the most prone to develop diffuse disease with parenchymal opacification, probably representing aerogenous spread. Low levels of alpha2-integrin receptors were found in bronchioloalveolar carcinoma which developed parenchymal opacification.

Basal ganglia network by constrained spherical deconvolution: a possible cortico-pallidal pathway?

In the recent past, basal ganglia circuitry was simplified as represented by the direct and indirect pathways and by hyperdirect pathways. Based on data from animal studies, we hypothesized a fourth pathway, the cortico‐pallidal, pathway, that complements the hyperdirect pathway to the subthalamus. Ten normal brains were analyzed by using the high angular resolution diffusion imaging—constrained spherical deconvolution (CSD)‐based technique. The study was performed with a 3T magnetic resonance imaging (MRI) scanner (Achieva, Philips Healthcare, Best, Netherlands); by using a 32‐channel SENSE head coil. We showed that CSD is a powerful technique that allows a fine evaluation of both the long and small tracts between cortex and basal ganglia, including direct, indirect, and hyperdirect pathways. In addition, a pathway directly connecting the cortex to the globus pallidus was seen. Our results confirm that the CSD tractography is a valuable technique allowing a reliable reconstruction of small‐ and long‐fiber pathways in brain regions with multiple fiber orientations, such as basal ganglia. This could open a future scenario in which CSD could be used to focally target with deep brain stimulation (DBS) the small bundles within the basal ganglia loops.