Loredana Satta

Role of SPECT/CT in the preoperative assessment of hyperparathyroid patients

Purpose.Our purpose was to assess the clinical value and additional benefit of fusion single-photon computed tomography (SPECT) and computed tomography (CT) images in locating the parathyroids in a selected group of patients affected by primary (PHP) and secondary hyperparathyroidism (SHP).Materials and methods.Sixteen patients (11 women and five men; age range 35–80 years) with severe hyperparathyroidism (HP) (ten PHP, six SHP) were studied by ultrasound (US), and, after i.v. injection of 370 MBq of 99mTc-sestamibi, by planar parathyroid scintigraphy, SPECT and SPECT/CT using a dualdetector scintillation camera GE Infinia Hawkeye. All patients underwent parathyroidectomy.Results.US findings were inconclusive in 12/16 patients affected by multinodular goitre, and two probable eutopic parathyroid glands were identified. “Double phase” parathyroid scintigraphy identified 14 probable parathyroid glands, SPECT 23 (14 ectopic and nine eutopic) and SPECT/CT confirmed all 23 probable parathyroid lesions, offering more precise localisation and an evident improvement in diagnostic accuracy. Sixteen of these foci of increased uptake were hyperplastic parathyroid glands, six were adenomas, one was a parathyroid carcinoma and one was a thyroid follicular carcinoma. Surgical detection of the 23 sestamibi-positive lesions was correctly matched with 100% of SPECT/CT images and 61% of SPECT data alone. Hybrid imaging thus provided additional data in 39% of lesions, and in three patients with retrotracheal glands, it modified the surgical approach.Conclusions.We believe 99mTc-sestambi SPECT/CT to be a more reliable presurgical method to study a patient subgroup affected by PHP or SHP in whom conventional US and other scintigraphic methods have failed for intrinsic reasons due to the concomitant presence of multinodular goitre or ectopic parathyroid gland. The additional practical benefit derived from this methodology was evident. In fact, anatomical information provided by CT enables precise localisation of the functional abnormalities highlighted by SPECT, and both are essential to a correct surgical approach.

Comparison of MRI, EEG, EPs and ECD-SPECT in Wilson's disease

Objectives – The purpose of this study is to evaluate the efficiency of a few methodologies in detecting anatomo‐functional brain abnormalities in patients with Wilsons disease. Materials and methods – Twenty‐three patients with Wilsons disease underwent almost simultaneously brain magnetic resonance imaging (MRI), computerized electroencephalography (EEG), multimodal evoked potentials (EPs) and ECD single photon computerized tomography (SPECT) evaluation. The clinical picture was of the neurologic type in 8 patients and of the hepatic type in 15. Results – MRI was abnormal in 7 patients with neurological manifestations. The EPs proved pathologic in 7 neurologically symptomatic patients and in 4 cases with hepatic form. These results agree with those reported in other case studies. The EEG records were abnormal only in 3 cases. Nevertheless, the most interesting finding of this study is the particular frequency (86%) of diffuse or focal decrease of ECD uptake shown by brain SPECT. Conclusion – We highlight the use of this interesting procedure in the therapeutic monitoring of this disease.

Brain perfusion abnormalities in patients with euthyroid autoimmune thyroiditis

PurposeBrain perfusion abnormalities have recently been demonstrated by single-photon emission computed tomography (SPECT) in rare cases of severe Hashimoto’s thyroiditis (HT) encephalopathy; moreover, some degree of subtle central nervous system (CNS) involvement has been hypothesised in HT, but no direct evidence has been provided so far. The aim of this study was to assess cortical brain perfusion in patients with euthyroid HT without any clinical evidence of CNS involvement by means of 99mTc-ECD brain SPECT. Sixteen adult patients with HT entered this study following informed consent.MethodsThe diagnosis was based on the coexistence of high titres of anti-thyroid auto-antibodies and diffuse hypoechogenicity of the thyroid on ultrasound in association with normal circulating thyroid hormone and TSH concentrations. Nine consecutive adult patients with non-toxic nodular goitre (NTNG) and ten healthy subjects matched for age and sex were included as control groups. All patients underwent 99mTc-ECD brain SPECT. Image assessment was both qualitative and semiquantitative. Semiquantitative analysis was performed by generation of four regions of interest (ROI) for each cerebral hemisphere—frontal, temporal, parietal and occipital—and one for each cerebellar hemisphere in order to evaluate cortical perfusion asymmetry. The Asymmetry Index (AI) was calculated to provide a measurement of both magnitude and direction of perfusion asymmetry.ResultsAs assessed by visual examination, 99mTc-ECD cerebral distribution was irregular and patchy in HT patients, hypoperfusion being more frequently found in frontal lobes. AI revealed abnormalities in 12/16 HT patients, in three of the nine NTNG patients and in none of the normal controls. A significant difference in the mean AI was found between patients with HT and both patients with NTNG (p<0.003) and normal controls (p<0.001), when only frontal lobes were considered.ConclusionThese results show the high prevalence of brain perfusion abnormalities in euthyroid HT. These abnormalities are similar to those observed in cases of severe Hashimoto’s encephalopathy and may suggest a higher than expected involvement of CNS in thyroid autoimmune disease.

Brain MRI and SPECT in the diagnosis of early neurological involvement in Wilson’s disease

PurposeTo evaluate the impact of brain MRI and single-photon emission computed tomography (SPECT) in early detection of central nervous system abnormalities in patients affected by Wilson’s disease (WD) with or without neurological involvement.MethodsOut of 25 consecutive WD patients, 13 showed hepatic involvement, ten hepatic and neurological manifestations, and twp hepatic, neurological, and psychiatric symptoms, including mainly movement disorders, major depression, and psychosis. Twenty-four healthy, age-gender matched subjects served as controls. All patients underwent brain MRI and 99mTc-ethyl-cysteinate dimer (ECD) SPECT before starting specific therapy. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare differences in 99mTc-ECD brain uptake between the two groups.ResultsBrain MRI showed T2-weighted hyperintensities in seven patients (28%), six of whom were affected by hepatic and neurological forms. Brain perfusion SPECT showed pathological data in 19 patients (76%), revealing diffuse or focal hypoperfusion in superior frontal (Brodmann area (BA) 6), prefrontal (BA 9), parietal (BA 40), and occipital (BA 18, BA 39) cortices in temporal gyri (BA 37, BA 21) and in caudatus and putamen. Moreover, hepatic involvement was detected in nine subjects; eight presented both hepatic and neurological signs, while two exhibited WD-correlated hepatic, neurological, and psychiatric alterations. All but one patient with abnormal MRI matched with abnormal ECD SPECT. Pathologic MRI findings were obtained in six out of ten patients with hepatic and neurological involvement while abnormal ECD SPECT was revealed in eight patients. Both patients with hepatic, neurological, and psychiatric involvement displayed abnormal ECD SPECT and one displayed an altered MRI.DiscussionThese findings suggest that ECD SPECT might be useful in detecting early brain damage in WD, not only in the perspective of assessing and treating motor impairment but also in evaluating better the less investigated disorders in the cognitive domain.