Thymic pathologies in myasthenia gravis: a preoperative assessment of CAT scan and nuclear based imaging.

Precise diagnostic work up of a suspected thymic pathology in patients with myasthenia gravis (MG) is very important for potential surgical implications and further disease course. In this study the diagnostic value of combined preoperative radiological (CAT scan) and nuclear based imaging (octreotide and thallium scintigraphy) in patients with MG was evaluated. Twenty four patients were included. Histopathology revealed thymoma in nine patients, thymic carcinoma (TC) in one patient, lymphofollicular hyperplasia in seven patients, and involuted thymus in another seven patients. Diagnostic sensitivity for detecting thymoma/TC was 80 % in CAT scan as well as in somatostatin scintigraphy; the combination of both procedures reached 90 %. However, the diagnostic specifity to exclude thymoma in CAT scan was 100 % and in octreotide scintigraphy 85.7 %. Semiquantitative octreotide uptake significantly correlated with histological grading of thymoma/TC (r = 0.764) and histological proliferation rate Ki67 (r = 0.894). Thallium scintigraphy was positive only in one out of four thymoma cases. In this study, somatostatin scintigraphy has been shown to be a useful additional diagnostic technique in detecting thymic malignancies in patients with MG. These results might be especially helpful in patients with late onset MG as these patients are in general no candidates for thymectomy.

Recessively inherited parkinsonism: effect of ATP13A2 mutations on the clinical and neuroimaging phenotype.

OBJECTIVE: To determine clinical features and to identify changes in brain structure and function in compound heterozygous and heterozygous ATP13A2 mutation carriers. DESIGN: Prospective multimodal clinical and neuroimaging study. SETTING: University of Lübeck, Lübeck, Germany. PARTICIPANTS: Eight family members of a large Chilean pedigree with Kufor-Rakeb syndrome (KRS). INTERVENTIONS: Clinical characterization, dopamine transporter (DAT) imaging, voxel-based morphometry (VBM), and transcranial sonography (TCS). MAIN OUTCOME MEASURES: Frequency of parkinsonian signs, brain structure, and functional alterations. RESULTS: The only available patient with compound heterozygous KRS showed a markedly reduced striatal DAT density bilaterally. Magnetic resonance imaging revealed severe global brain atrophy as well as iron deposition in the basal ganglia. The heterozygous mother had definite parkinsonism with reduced DAT density in both putamina. While all asymptomatic heterozygous siblings displayed subtle extrapyramidal signs, DAT imaging revealed striatal tracer uptake within physiological levels. Voxel-based morphometry revealed an increase in gray matter volume in the right putamen and a decrease in the cerebellum of the heterozygous carriers. In all mutation carriers, the substantia nigra had a normal appearance on TCS. CONCLUSIONS: Single ATP13A2 heterozygous mutations may be associated with clinical signs of parkinsonism and contribute to structural and functional brain changes. Lack of hyperechogenicity in the substantia nigra may be a distinctive feature of this form of genetic parkinsonism. This, along with the finding of iron in the basal ganglia in our patient with KRS, implies a different underlying pathophysiology compared with other monogenic forms of parkinsonism and idiopathic PD and may place KRS among the syndromes of neurodegeneration with brain iron accumulation (NBIA).