Symptomatic paroxysmal hypertension without significantly elevated catecholamine concentrations and with no evidence of an underlying adrenal tumor is known as pseudopheochromocytoma. We describe the case of a female patient with paroxysmal hypertensive crises accompanied by headache, vertigo, tachycardia, nausea and altered mental status. Previously, she was treated for a longer period with alprazolam due to panic disorder. Causes of secondary hypertension were excluded. Neurological triggers (intracranial tumor, cerebral vascular lesions, hemorrhage, and epilepsy) could not be detected. Setting of the diagnosis of pseudopheochromocytoma treatment was initiated with alpha- and beta-blockers resulting in reduced frequency of symptoms. Alprazolam was restarted at a daily dose of 1 mg. The patient’s clinical condition improved rapidly and the dosage of alpha- and beta-blockers could be decreased. We conclude that the withdrawal of an anxiolytic therapeutic regimen may generate sympathetic overdrive resulting in life-threatening paroxysmal malignant hypertension and secondary encephalopathy. We emphasize that pseudopheochromocytoma can be diagnosed only after exclusion of the secondary causes of hypertension. We highlight the importance of a psychopharmacological approach to this clinical entity.
20 June 2022 in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Joint Diseases and Related Surgery (JDRS), the official journal of the Turkish Joint Diseases Foundation, is an international, peer-reviewed, immediate open access journal. All published articles in JDRS has been free for everyone, without embargo, since 1990.
Background/Objectives: Artificial intelligence (AI) is a promising tool for the enhancement of physician workflow and serves to further improve the efficiency of their diagnostic evaluations. This study aimed to assess the performance of an AI-based bone scan noise-reduction filter on noisy, low-count images in a routine clinical environment. Methods: The performance of the AI bone-scan filter (BS-AI filter) in question was retrospectively evaluated on 47 different patients’ 99mTc-MDP bone scintigraphy image pairs (anterior- and posterior-view images), which were obtained in such a manner as to represent the diverse characteristics of the general patient population. The BS-AI filter was tested on artificially degraded noisy images—75, 50, and 25% of total counts—which were generated by binominal sampling. The AI-filtered and unfiltered images were concurrently appraised for image quality and contrast by three nuclear medicine physicians. It was also determined whether there was any difference between the lesions seen on the unfiltered and filtered images. For quantitative analysis, an automatic lesion detector (BS-AI annotator) was utilized as a segmentation algorithm. The total number of lesions and their locations as detected by the BS-AI annotator in the BS-AI-filtered low-count images was compared to the total-count filtered images. The total number of pixels labeled as lesions in the filtered low-count images in relation to the number of pixels in the total-count filtered images was also compared to ensure the filtering process did not change lesion sizes significantly. The comparison of pixel numbers was performed using the reduced-count filtered images that contained only those lesions that were detected in the total-count images. Results: Based on visual assessment, observers agreed that image contrast and quality were better in the BS-AI-filtered images, increasing their diagnostic confidence. Similarities in lesion numbers and sites detected by the BS-AI annotator compared to filtered total-count images were 89%, 83%, and 75% for images degraded to counts of 75%, 50%, and 25%, respectively. No significant difference was found in the number of annotated pixels between filtered images with different counts (p > 0.05). Conclusions: Our findings indicate that the BS-AI noise-reduction filter enhances image quality and contrast without loss of vital information. The implementation of this filter in routine diagnostic procedures reliably improves diagnostic confidence in low-count images and elicits a reduction in the administered dose or acquisition time by a minimum of 50% relative to the original dose or acquisition time.
Background: Since metabolic diseases and atherosclerotic vascular events are firmly associated, herein we investigate changes in central microcirculation and atherosclerosis-related body fat distribution in patients with type 2 diabetes mellitus and obesity. Methods: Resting brain perfusion single-photon emission computed tomography (SPECT) imaging with Technetium-99m hexamethylpropylene amine oxime ([99mTc]Tc-HMPAO SPECT) was performed, and the breath-holding index (BHI) and carotid intima-media thickness (cIMT) were measured to characterise central microcirculation. Besides CT-based abdominal fat tissue segmentation, C-peptide level, glycaemic and anthropometric parameters were registered to search for correlations with cerebral blood flow and vasoreactivity. Results: Although no significant difference was found between the resting cerebral perfusion of the two patient cohorts, a greater blood flow increase was experienced in the obese after the breath-holding test than in the diabetics (p < 0.05). A significant positive correlation was encountered between resting and provocation-triggered brain perfusion and C-peptide levels (p < 0.005). BMI and cIMT were negatively correlated (rho = −0.27 and −0.23 for maximum and mean cIMT, respectively), while BMI and BHI showed a positive association (rho = 0.31 and rho = 0.29 for maximum and mean BHI, respectively), which could be explained by BMI-dependent changes in fat tissue distribution. cIMT demonstrated a disproportional relationship with increasing age, and higher cIMT values were observed for the men. Conclusions: Overall, C-peptide levels and circulatory parameters seem to be strong applicants to predict brain microvascular alterations and related cognitive decline in such patient populations.
Background: Neuroblastoma (NB) is one of the most common solid tumors in children, still showing a high mortality rate despite recent advances in therapy. A recent breakthrough was the introduction of Dinutuximab beta, yielding further improvements in survival. Dinutuximab beta is an anti-GD2 monoclonal antibody that targets GD2 expressed on the cell surface of neuroblastoma cells. Evidence suggests that Dinutuximab beta combined with Nivolumab may offer an effective synergistic treatment approach. Methods: In our center, immunotherapy was introduced in 2021 as part of maintenance treatment. The aim of this retrospective study was to analyze our data with a focus on the response, side effect profile and tolerability of Dinutuximab beta in HR and relapsed or refractory (r/r) NB. Results: Between 2021 and 2024, we treated 15 patients with neuroblastoma. Twelve patients had high-risk disease, of whom five received Dinutuximab beta as part of maintenance treatment according to protocol HR-NBL 1.8/SIOPEN. Two patients achieved complete remission after immunotherapy. One achieved long-lasting remission, while another relapsed. Three patients with inoperable tumors developed a partial response, but they relapsed and were diagnosed with metastases later. These patients subsequently initiated treatment with Temozolomide + Irinotecan in combination with Dinutuximab beta and also with Nivolumab as a relapse protocol. Therapeutic responses were assessed by the imaging, pathology and flow cytometry analysis of bone marrow. Apart from one complication (hypotension as part of capillary leak syndrome) subsiding spontaneously, no other severe adverse events were observed. Conclusions: Our experiences confirm that immunotherapy, including Dinutuximab beta and Nivolumab, is safe and well tolerated. The standardization of the application of Dinutuximab beta and in combination with novel therapeutic agents in maintenance and refractory/relapsed cases may contribute to improved treatment outcome results.