Differential diagnosis between Parkinson's disease (PD) and Atypical Parkinsonisms, mainly Progressive Supranuclear Palsy (PSP) and Multiple System Atrophy (MSA), remains challenging. The low sensitivity of macroscopic findings at imaging might limit early diagnosis. The availability of iron-sensitive MR techniques and high magnetic field MR scanners provides new insights in evaluating brain structures in degenerative parkinsonisms. Quantitative Susceptibility Mapping (QSM) allows quantifying tissue iron content and could be sensitive to microstructural abnormalities which precede the appearence of regional atrophy. We measured the magnetic susceptibility (χ) of nigral and extranigral regions in patients with PD, PSP and MSA to evaluate the potential utility of the QSM technique for differential diagnosis. 65 patients (36 PD, 14 MSA, 15 PSP) underwent clinical and radiological evaluation with 3 T MRI. QSM maps were obtained from GRE sequences. ROI were drawn on substantia nigra (SN), red nucleus (RN), subthalamic nucleus (STN), putamen, globus pallidus and caudate. χ values were compared to detect inter-group differences. The highest diagnostic accuracy for PSP (area under the ROC curve, AUC, range 0.9-0.7) was observed for increased χ values in RN, STN and medial part of SN whereas in MSA (AUC range 0.8-0.7) iron deposition was significantly higher in the putamen, according to the patterns of pathological involvement that characterize the different diseases. QSM could be used for iron quantification of nigral and extranigral structures in all degenerative parkinsonisms and should be tested longitudinally in order to identify early microscopical changes.

The decline of voluntary bulbar functions such as speech and swallowing are among the clinical manifestations of amyotrophic lateral sclerosis (ALS) influencing a worst prognosis. Differential diagnosis between the contribution of upper motor neuron (UMN) and lower motor neuron degeneration to the bulbar impairment is often hard. Thinning and T2* hypointensity of the primary motor cortex have been recently suggested as possible MRI markers of UMN impairment in ALS patients, but little research has purposely targeted the orofacial region of the primary motor cortex (fM1). With the aim of finding an MRI marker of UMN impairment responsible for bulbar dysfunction, we investigated the T2* signal intensity of fM1 and the relationship with bulbar impairment in ALS patients. Fifty-five ALS patients were examined with 3 T MRI. Their fM1 was evaluated both qualitatively in terms of T2* signal intensity and quantitatively by measuring its magnetic susceptibility with Quantitative Susceptibility Mapping (QSM). Bulbar functions were assessed clinically, by neurological examination and using the items 1-3 of the ALSFRS-R, and with neurophysiological tests. The marked hypointensity of fM1 was detected in 25% of ALS patients, including all patients with bulbar onset, and was 74% sensitive, 100% specific and 91% accurate in diagnosing functional bulbar impairment. Such hypointensity involved the middle and ventral part of fM1 and was usually visible in both hemispheres. The magnetic susceptibility was significantly higher in patients with marked fM1 hypointensity than in the other patients (p ≤ .001). The relationship with clinical and neurophysiological data suggests that such feature could be a marker of UMN degeneration for voluntary bulbar functions.

Quantitative Susceptibility Mapping (QSM) can measure iron concentration increase in the primary motor cortex (M1) of patients with Amyotrophic Lateral Sclerosis (ALS). However, such alteration is confined to only specific regions interested by upper motor neuron pathology; therefore, mean QSM values in the entire M1 have limited diagnostic accuracy in discriminating between ALS patients and control subjects. This study investigates the diagnostic accuracy of a broader set of M1 QSM distribution indices in classifying ALS patients and controls. Mean, standard deviation, skewness and kurtosis of M1 QSM values were used either individually or as combined predictors in support vector machines. The classification performance was compared to that obtained by the radiological assessment of T2* signal hypo-intensity of M1 in susceptibility-weighted MRI. The least informative index for the classification of ALS patients and controls was the subject’s mean QSM value in M1. The highest diagnostic performance was obtained when all the distribution indices of positive QSM values in M1 were considered, which yielded a diagnostic accuracy of 0.90, with sensitivity = 0.89 and specificity = 1. The radiological assessment of M1 yielded a diagnostic accuracy of 0.79, with sensitivity = 0.76 and specificity = 0.90. The joint evaluation of QSM distribution indices could support the clinical examination in ALS diagnosis and patient monitoring.

Background and Purpose: We aimed to test whether synthetic T1‐weighted imaging derived from a post‐contrast Quantitative Transient‐state Imaging (QTI) acquisition enabled revealing pathological contrast enhancement in intracranial lesions.Methods: The analysis included 141 patients who underwent a 3 Tesla‐MRI brain exam with intravenous contrast media administration, with the post‐contrast acquisition protocol comprising a three‐dimensional fast spoiled gradient echo (FSPGR) sequence and a QTI acquisition. Synthetic T1‐weighted images were generated from QTI‐derived quantitative maps of relaxation times and proton density. Two neuroradiologists assessed synthetic and conventional post‐contrast T1‐weighted images for the presence and pattern of pathological contrast enhancement in intracranial lesions. Enhancement volumes were quantitatively compared.Results: Using conventional imaging as a reference, synthetic T1‐weighted imaging was 93% sensitive in revealing the presence of contrast enhancing lesions. The agreement for the presence/absence of contrast enhancement was almost perfect both between readers (k = 1 for both conventional and synthetic imaging) and between sequences (k = 0.98 for both readers). In 91% of lesions, synthetic T1‐weighted imaging showed the same pattern of contrast enhancement visible in conventional imaging. Differences in enhancement pattern in the remaining lesions can be due to the lower spatial resolution and the longer acquisition delay from contrast media administration of QTI compared to FSPGR. Overall, enhancement volumes appeared larger in synthetic imaging.Conclusions: QTI‐derived post‐contrast synthetic T1‐weighted imaging captures pathological contrast enhancement in most intracranial enhancing lesions. Further comparative studies employing quantitative imaging with higher spatial resolution is needed to support our data and explore possible future applications in clinical trials.

Two patients with CSF shunting systems exhibited symptoms of altered intracranial pressure. Initial neuroimaging led to misinterpretation, but integrating clinical history and follow-up imaging revealed the true diagnosis. In the first case, reduced ventricular size was mistaken for CSF overdrainage, while the actual problem was increased intracranial pressure, as seen in slit ventricle syndrome. In the second case, symptoms attributed to intracranial hypertension were due to CSF overdrainage causing tonsillar displacement and hydrocephalus. Adjusting the spinoperitoneal shunt pressure resolved symptoms and imaging abnormalities. These cases highlight the necessity of correlating clinical presentation with a deep understanding of CSF dynamics in shunt assessments.

Patients with corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP) often show the loss of the "swallow tail sign", which reflects degeneration of dopaminergic neurons and iron accumulation in the substantia nigra pars compacta, and peculiar neuroradiological signs which are, respectively, asymmetrical frontoparietal atrophy and midbrain atrophy. A T2* hypointense rim likely reflecting presence and distribution of neuroinflammation has been recently reported in the frontal cortex of CBS patients. Here we investigated (i) the frequency of conventional radiological signs associated with CBS and PSP and (ii) presence, distribution and frequency of the T2* signal hypointensity in the frontal cortex in CBS and PSP patients. In addition, (iii) we explored possible associations between T2* hypointensity in the frontal cortex and clinical symptoms. Sixty-two patients were retrospectively included in the study (14 CBS and 48 PSP). Two neuroradiologists inspected the 3T MR datasets and recorded the presence/absence of: asymmetric frontoparietal atrophy, midbrain atrophy, loss of the "swallow tail sign" and T2* hypointensity of the frontal cortex. Asymmetrical frontoparietal atrophy and T2* hypointensity in the frontal cortex were more frequent in CBS patients (p<0.001) whereas midbrain atrophy and the loss of the "swallow tail sign" were so in PSP patients (p<0.001). The T2* signal hypointensity in the frontal cortex was detected in 14 CBS (100%) and five PSP (10%) patients and had three possible patterns of distribution associated with specific symptoms: (A) involvement of the hand knob only (three CBS and no PSP patients) in patients with unilateral ideomotor apraxia; (B) involvement of the primary motor cortex which extended beyond the hand knob (two CBS and five PSP patients); both CBS patients had bilateral ideomotor apraxia; (C) involvement of the primary motor cortex, the superior and/or the middle frontal gyrus (nine CBS and no PSP patients); all but one of these patients had ideomotor limb apraxia and all had speech/language impairment. The T2* signal hypointensity in the frontal cortex may be an additional radiological sign to be assessed in patients with atypical parkinsonism. Its distribution across the frontal gyri likely reflects clinical symptoms. The pathological assessment of CBS cases would support the robustness of these results.