PET-CT in brain disorders: The South African context.

Positron emission tomography combined with X-ray computed tomography (PET-CT) has an established role in the management of brain disorders, but may be underutilised in South Africa. Possible barriers to access include the limited number of PET-CT facilities and the lack of contemporary guidelines for the use of brain PET-CT in South Africa. The current review aims to highlight the evidence-based usage of brain Positron emission tomography (PET) in dementia, movement disorders, brain tumours, epilepsy, neuropsychiatric lupus, immune-mediated encephalitides, and brain infections. While being areas of research, there is currently no clinical role for the use of PET-CT in traumatic brain injury or in psychiatric or neurodevelopmental disorders. Strategies to expand the appropriate use of PET-CT in brain disorders are discussed in this article.

Nuclear Neuroimaging in Social Anxiety Disorder: A Review.

In psychiatric research, nuclear imaging complements MRI. A recent neuroimaging review of social anxiety disorder focused predominantly on MRI, omitting the contribution of nuclear imaging methods. Nuclear imaging investigations of neural activity are sparse but have generally yielded results consistent with studies performed using MRI. Evidence for disturbances in neurotransmitter systems in social anxiety disorder is limited but suggestive of both serotonergic and dopaminergic dysfunction. Research focusing on additional molecular targets using existing and novel tracers, combined with recent technologic innovations and trends in collaborative methodology, may shape future nuclear imaging endeavors in this field.

Resting functional connectivity in social anxiety disorder and the effect of pharmacotherapy.

Neuroimaging research has reported differences in resting-state functional connectivity (RFC) between social anxiety disorder (SAD) patients and healthy controls (HCs). Limited research has examined the effect of treatment on RFC in SAD. We performed a study to identify differences in RFC between SAD and HC groups, and to investigate the effect of pharmacotherapy on RFC in SAD. Seed-based RFC analysis was performed on technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) SPECT scans using a cross-subject approach in SPM-12. Seeds were chosen to represent regions in a recently published network model of SAD. A second-level regression analysis was performed to further characterize the underlying relationships identified in the group contrasts. Twenty-three SAD participants were included, of which 18 underwent follow-up measures after an 8-week course of citalopram or moclobemide. Fifteen healthy control (HC) scans were included. SAD participants at baseline demonstrated several significant connectivity disturbances consistent with the existing network model as well as one previously unreported finding (increased connectivity between cerebellum and posterior cingulate cortex). After therapy, the SAD group demonstrated significant increases in connectivity with dorsal anterior cingulate cortex which may explain therapy-induced modifications in how SAD sufferers interpret emotions in others and improvements in self-related and emotional processing.

Chest pain on exertion after the Takeuchi repair of anomalous origin of the left coronary artery: right ventricular ischemia due to severe pulmonary outflow tract obstruction.

Right ventricular (RV) outflow obstruction (in the form of valvar or supravalvular pulmonary stenosis) is a well-known complication of the Takeuchi procedure. We describe a 13-year-old male with exertional chest pain, pulmonary stenosis, RV hypertrophy, and consequent RV ischemia, which was confirmed using stress echocardiography and single-photon emission tomography.

Hybrid imaging using low-dose, localizing computed tomography enhances lesion localization in renal hyperparathyroidism.

BACKGROUND: Preoperative localization of parathyroid lesions is potentially beneficial in renal patients with hyperparathyroidism. The aim of this study was to determine the localizing value of hybrid single-photon emission computed tomography combined with low-dose x-ray computed tomography (SPECT/LDCT) compared with SPECT alone and whether the LDCT improved reader confidence. PATIENTS AND METHODS: A retrospective study examined parathyroid scintigraphy results of patients previously referred with a diagnosis of renal hyperparathyroidism. All patients underwent planar scintigraphy using technetium-99m (Tc)-pertechnetate, which was immediately followed with Tc-sestamibi and SPECT/LDCT ∼60 min after sestamibi injection and a delayed static image to assess differential washout. Planar subtraction images were generated. Two nuclear physicians, assisted by a radiologist, reported on planar+SPECT images followed by planar+SPECT/LDCT images. RESULTS: Thirty-seven patients (males: 21; females: 16) were included (mean age 39 years, range: 23.9-55.5). Mean creatinine level was 878 µmol/l (109-1839), mean corrected calcium level was 2.42 mmol/l (1.77-3.64), and median parathyroid hormone level was 156.2 pmol/l (2.4 to >201). Twenty-three patients had positive planar and SPECT results (46 lesions), six had positive planar results only, and eight had negative scintigraphy results. In the patients with positive planar and SPECT results, 35 lesions were classified as eutopic and 11 as ectopic. After the addition of LDCT, localization of five eutopic lesions (on SPECT) was amended to ectopic locations (on SPECT/LDCT), principally by identifying posteriorly situated glands. The addition of LDCT led to increased confidence in localization in all cases. CONCLUSION: Compared with SPECT alone, SPECT/LDCT is beneficial in preoperative localization of lesions in renal hyperparathyroidism.