Andrea Righini

Imaging essential tremor.

To investigate over time changes in striatal dopamine transporter (DAT), we performed two sequential N‐ω‐fluoropropyl‐2β‐carbomethoxy‐3β‐(4‐iodophenyl) tropane single photon computed tomography (SPECT) scans in 20 subjects with essential tremor (ET), in 13 with Parkinson disease (PD) and in 23 healthy controls (HC, one scan only). We also performed an [99mTc]ethyl cysteinate dimer bicisate SPECT exam for regional brain network analysis in 9 ET, in a second group of 18 PD (9 with tremor, tPD and 9 akinetic‐rigid dominant, arPD) and in 8 HC. PD subjects had a reduced DAT binding in comparison to ET and HC with an annual decline rate of 7.3% in the contralateral putamen. There were no mean uptake differences between ET and HC at baseline and no uptake loss over time in ET. A discriminant analysis grouped 30% (first scan) and 5% (second scan) of ET as PD and a partition analysis showed overlap between ET and PD for caudate nucleus uptake. Spatial covariance analysis revealed that the expression of the PD‐related regional pattern separated both tPD and arPD from ET and HC. In conclusion, PD and ET do not share a common pattern of dopaminergic loss over time. However, mild impairment of dopamine transporter in the caudate nucleus may contribute to tremor onset in ET.

Early Cerebral Lesions in Cytomegalovirus Infection: Prenatal MR Imaging

PURPOSEnTo assess the diagnostic and prognostic value of fetal cerebral magnetic resonance (MR) imaging of congenital cytomegalovirus (CMV) infection in comparison with that of level II ultrasonography (US).nnnMATERIALS AND METHODSnInstitutional review board approval and informed consent for fetal MR imaging and data collection were obtained. Thirty-eight fetuses with CMV infection, examined by using serial level II US, underwent fetal MR imaging (mean gestational age, 25 weeks; age range at first fetal MR examination, 20-34 weeks). The frequency of pathologic findings at US (29 cases with transabdominal examination and nine cases with both transabdominal and transvaginal examination) and MR imaging was calculated, and a comparison between techniques by considering number (paired Student t test) and type (McNemar test) of finding was made. A comparison (paired Student t test) in cases of repeated fetal (nine of 38) and/or postnatal (14 of 38) MR imaging was obtained. Diagnostic and prognostic sensitivity was calculated for both techniques.nnnRESULTSnUS and MR imaging findings were both normal in 47% of cases (18 of 38). Abnormal studies were reported in 26% (10 of 38) of US and 53% (20 of 38) of MR imaging cases. In 47% of cases (18 of 38), MR imaging provided additional information (P = .0002). MR imaging had better results than US in detecting polar temporal lesions (P = .0001), microencephaly (P = .03), and cortical anomalies (P = .06). In 44.5% of cases (four of nine), the second fetal MR examination results showed new findings (P = .05). In 79% of cases, postnatal MR imaging results confirmed prenatal findings (P = .08). MR imaging had higher sensitivity than US in detecting brain anomalies (92% vs 38%) and in predicting symptomatic infection (83% vs 33%). US and MR imaging revealed low positive predictive values (29% vs 36%).nnnCONCLUSIONnFetal MR imaging results can show abnormalities in the fetal brain after CMV infection, even when US results are normal. The early detection of some brain abnormalities, such as microencephaly and cortical anomalies, may substantially influence the prognosis of fetal infection.

Magnetic resonance imaging assessment of brain maturation in preterm neonates with punctate white matter lesions

IntroductionEarly white matter (WM) injury affects brain maturation in preterm infants as revealed by diffusion tensor imaging and volumetric magnetic resonance (MR) imaging at term postmenstrual age (PMA). The aim of the study was to assess quantitatively brain maturation in preterm infants with and without milder forms of WM damage (punctate WM lesions, PWML) using conventional MRI.MethodsBrain development was quantitatively assessed using a previously validated scoring system (total maturation score, TMS) which utilizes four parameters (progressive myelination and cortical infolding, progressive involution of glial cell migration bands and germinal matrix tissue). PWML were defined as foci of increased signal on T1-weighted images and decreased signal on T2-weighted images with no evidence of cystic degeneration. A group of 22 preterm infants with PWML at term PMA (PWML group) were compared with 22 matched controls with a normal MR appearance.ResultsThe two groups were comparable concerning gestational age, birth weight and PMA. TMS was significantly lower in the PWML group than in the control group (mean TMS 12.44u2009±u20092.31 vs 14.00u2009±u20091.44; Pu2009=u20090.011). Myelination (mean 2.76u2009±u20090.42 PWML group vs 3.32u2009±u20090.55 control group, Pu2009=u20090.003) and cortical folding (3.64u2009±u20090.79 vs 4.09u2009±u20090.43, Pu2009=u20090.027) appeared to be significantly delayed in babies with PWML.ConclusionConventional MRI appears able to quantify morphological changes in brain maturation of preterm babies with PWML; delayed myelination and reduced cortical infolding seem to be the most significant aspects.

Prenatal magnetic resonance imaging evaluation of ischemic brain lesions in the survivors of monochorionic twin pregnancies: report of 3 cases.

The death of 1 twin of monochorionic pairs is associated with a significant risk of brain hypoxic-ischemic damage in the survivor. Ultrasound may diagnose cerebral anomalies only a few weeks after the event. We report 3 cases of single survivors of monochorionic-twin pregnancies in which prenatal magnetic resonance imaging detected brain changes earlier and with better definition of the brain abnormalities than ultrasound.

Water apparent diffusion coefficient and T2 changes in the acute stage of maple syrup urine disease: evidence of intramyelinic and vasogenic-interstitial edema.

Background. The acute phase of the neonatal classical form of maple syrup urine disease (MSUD) is usually associated with generalized brain edema. Methods and Results. The authors present the case of a newborn infant in the acute stage of the classical form of MSUD in whom a remarkable decrease in the water apparent diffusion coefficient (ADC) in advanced myelinating white matter areas was associated with an increase in the T2 signal. This diffusion magnetic resonance imaging (MRI) pattern appears to be compatible with a rare kind of cytotoxic edema, the so‐called intramyelinic edema. At the same time, an increase in the ADC was seen in unmyelinated areas together with an increase in the T2 signal, a sign of a coexistent vasogenic‐interstitial edema. Conclusions. ADC measurements in MSUD provide more specific information than conventional MRI about the pathophysiology of white matter changes.

Genetic, clinical, and imaging characterization of one patient with late-onset, slowly progressive, pantothenate kinase-associated neurodegeneration

We report on a patient with late‐onset, pantothenate kinase‐associated neurodegeneration (PKAN) who revealed two new heterozygous mutations at gene testing and showed asymmetric moderately reduced striatal dopamine transporter binding with single photon emission computed tomography, possibly due to prolonged neuroleptic treatment. These findings expand the genetic and imaging spectrum of this rare disorder.

Prenatal magnetic resonance imaging of rhombencephalosynapsis and associated brain anomalies: report of 3 cases.

Rhombencephalosynapsis (RES) is a rare congenital abnormality characterized by vermian agenesis and fusion of the cerebellar hemispheres. In the 3 cases reported here, prenatal magnetic resonance imaging clearly depicted cerebellar features characteristic of RES, allowing a definite diagnosis.

Early Formative Stage of Human Focal Cortical Gyration Anomalies: Fetal MRI

OBJECTIVEnLimited information is available about the development of focal cortical gyration anomalies in the human brain. Using prenatal MRI, we characterized focal cortical gyration anomalies at an early formative stage and sought clues about the mechanisms of their development.nnnMATERIALS AND METHODSnFrom a large prenatal MRI database, 30 cases (gestational age, ≤ 24 weeks) with reported focal distortion of the cortical rim profile were selected. Eight cases were matched with histologic examinations; another seven had prenatal MRI, MRI autopsy, or postnatal MRI follow-up; and 15 had no follow-up but did present analogous abnormal cortical features. Focal cortical gyration anomalies were detectable when the brain was still smooth (i.e., physiological lissencephaly).nnnRESULTSnFour patterns of cortical plate anomaly were identified: wartlike (11 cases), abnormal invaginating sulcus (11 cases), sawtooth (six cases), and single or multiple bumps (two cases). A thinned or blurred subplate and intermediate zone in the focal cortical gyration anomaly site was detected in 80% of cases. All but two cases had other intracranial anomalies. Seven cases were classified as hypoxic-ischemic, five as genetic, and three as infective. In 15 cases, the cause could not be established. In five fetuses with further intrauterine or postnatal MRI, focal cortical gyration anomalies increased in complexity, fulfilling postnatal imaging criteria of polymicrogyria.nnnCONCLUSIONnFocal cortical gyration anomalies can be detected at the early sulcation process stage. The process leading to abnormal gyration may evolve faster than physiologic ones and seems to be related to alterations of parenchymal layering occurring before 24 weeks gestation. Most focal cortical gyration anomalies evolve toward what is currently considered polymicrogyria.

Is fetal magnetic resonance imaging indicated when ultrasound isolated mild ventriculomegaly is present in pregnancies with no risk factors?: Role of MR in fetuses with mild isolated ventriculomegaly on US

Ventriculomegaly (VM) is the most common brain anomaly in prenatal ultrasound (US) diagnosis. There is a general trend to perform fetal magnetic resonance imaging (MRI) when VM is severe (greater than 15u2009mm) and/or it is not isolated. The role of MRI is debated when VM is borderline (between 10 and 15u2009mm) and isolated. Some authors have subdivided borderline VM into mild (10 to 12u2009mm) and moderate (>12 to15u2009mm). The aim of the study was to evaluate the role of MR in the imaging protocol of fetal cases characterized by mild isolated VM and no risk factors.

Magnetic resonance imaging in prenatal diagnosis of dacryocystocele: report of 3 cases.

The presence of cystic dilation of the lacrimal drainage system (dacryocystocele) in the fetus must be differentiated from less benign paraocular masses. Three cases of dacryocystocele studied during fetal life by ultrasound and magnetic resonance (MR) imaging are reported. The accuracy of prenatal MR imaging facilitated a definite diagnosis depicting the characteristic triad of dacryocystocele: paraocular cystic mass in the medial canthus region, nasolacrimal duct enlargement, and intranasal cyst.