Publications by authors named "Ashok Muthukrishnan"

Our rationale was to review the imaging options for patients with primary hyperparathyroidism and to advocate for judicious use of 4-dimensional (4D) SPECT/CT to visualize diseased parathyroid glands in patients with complex medical profiles or in whom other imaging modalities fail. We review the advantages and disadvantages of traditional imaging modalities used in preoperative assessment of patients with primary hyperparathyroidism: ultrasound, SPECT, and 4D CT. We describe a scheme for optimizing and individualizing preoperative imaging of patients with hyperfunctioning parathyroid glands using traditional modalities in tandem with 4D SPECT/CT.

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The field of nuclear medicine is entering a new era of gamma-camera technology. Solid-state SPECT/CT systems will gradually replace the thallium-activated sodium-iodide NaI(Tl) systems. This digital technology allows drastic improvements in image quality, radiotracer dose reduction, and procedure efficiency.

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 Olfactory neuroblastoma (ONB), or esthesioneuroblastoma, is a rare neuroectodermal tumor of the nasal cavity and paranasal sinuses. Most of these tumors express somatostatin receptors (SSTRs), providing a potential target for radionuclide imaging with Ga-68 DOTATATE. However, this imaging modality has not been extensively studied in ONB.

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Background: Human nasal epithelial (HNE) cells can be sampled noninvasively and cultured to provide a model of the airway epithelium that reflects cystic fibrosis (CF) pathophysiology. We hypothesised that measures of HNE cell physiology would correlate directly with measures of lung physiology and therapeutic response, providing a framework for using HNE cells for therapeutic development and precision medicine.

Methods: We sampled nasal cells from participants with CF (CF group, n=26), healthy controls (HC group, n=14) and single CF transmembrane conductance regulator (CFTR) mutation carrier parents of the CF group (CR group, n=16).

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Background: Although mucus plugging is a well-reported feature of asthma, whether asthma and type 2 inflammation affect mucociliary clearance (MCC) is unknown.

Research Question: Does type 2 inflammation influence mucus clearance rates in patients with mild asthma who are not receiving corticosteroids?

Study Design And Methods: The clearance rates of inhaled radiolabeled particles were compared between patients with mild asthma with low (n = 17) and high (n = 18) levels of T2 inflammation. Fraction exhaled nitric oxide (Feno) was used to prospectively segregate subjects into T2 Lo (Feno < 25 ppb) and T2 Hi (Feno > 35 ppb) cohorts.

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Hybrid imaging with F-18 fludeoxyglucose positron emission tomography/magnetic resonance imaging (FDG PET/MRI) has increasing clinical applications supplementing conventional ultrasound, CT, and MRI imaging as well as hybrid PET/CT imaging in assessing cervical, endometrial, and ovarian cancer. This article summarizes the existing literature and discusses the emerging role of hybrid PET/MRI in gynecologic malignancies. Thus, far, the published literature on the applications of FDG PET/MRI shows that it can have a significant impact on patient management by improving the staging of the cancers compared with PET/CT, influencing clinical decision and treatment strategy.

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Neuroendocrine tumors (NETs) constitute a variety of neoplastic entities and exhibit variable degrees of neuroendocrine differentiation and phenotypes, as well as genetic profiles. Ga-DOTATATE PET is a novel imaging technique for NET. Although PET/CT is commonly utilized for oncologic imaging, PET/MRI is particularly suited for NETs, as MRI provides greater soft tissue contrast than CT, allowing for improved detection and characterization of NETs, particularly when liver metastasis is suspected or needs to be ruled out.

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Background: The addition of SPECT-CT to Tc-99 sestamibi has become a valuable tool for parathyroid localization in primary hyperparathyroidism (PHP). However, the enhanced sensitivity of this test can lead to unexpected and significant findings. We sought to identify the frequency and types of nonparathyroid detections by SPECT-CT.

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A 72-year-old man with a history of T1cN0M0 prostate adenocarcinoma and rising prostate-specific antigen underwent a fluciclovine PET/CT scan that showed high uptake in several para-aortic nodes, suspicious for prostate cancer. A right upper lobe single pulmonary nodule (SPN), demonstrated only mild uptake, which raised the suspicion for a lung primary. Subsequent FDG PET/CT showed high uptake in the SPN, revealing poorly differentiated adenocarcinoma at biopsy, but with no abnormal uptake in the para-aortic nodes.

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Nuclear imaging biomarkers illustrate unique aspects of lung physiology and are useful for assessing therapeutic effects in cystic fibrosis (CF) lung disease. We have developed a multiprobe method to simultaneously measure mucociliary clearance (MCC) and paracellular absorption (ABS). MCC is a direct measure of mucus clearance.

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Ga-DOTATATE imaging for meningiomas is gaining clinical use for selecting patients that may benefit from targeted therapy (eg, Lu-DOTATATE). We present an image of a 67-year-old man with an intracranial WHO grade III anaplastic meningioma. He underwent tumor resection followed by intensity-modulated radiation therapy but experienced a recurrence 25 months later.

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Background: Primary hyperparathyroidism is caused by single gland disease in 85% of cases and by multiglandular disease in 15%. Our aim was to discover if the addition of computed tomography acquisition/fusion on a hybrid scanner to traditional dual-phase single-photon emission tomography improves localization accuracy.

Methods: A prospective database was queried for the perioperative data of patients with sporadic primary hyperparathyroidism who had initial exploration from 2006-2014 with ≥6 month follow-up to define anatomy.

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Aim: Inhaled hypertonic saline increases mucociliary clearance, improves pulmonary function, and decreases exacerbations in cystic fibrosis (CF) but contributes to the already significant treatment burden of CF. Overnight delivery of inhaled medications via a specially designed nasal cannula-aerosol device (Trans-nasal Pulmonary Aerosol Delivery [tPAD]) is an alternative approach. Here, we test whether overnight inhalation of hypertonic saline via tPAD improves mucociliary clearance and assess the tolerability of the device.

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Brown adipose tissue (BAT) has been widely reported to affect the efficacy of F-FDG PET in oncology. Several small studies have found that warming the patient both before F-FDG injection and during the uptake phase can reduce the frequency of BAT uptake. Pharmaceutical approaches such as propranolol and diazepam have also been used.

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Airway surface liquid hyperabsorption and mucus accumulation are key elements of cystic fibrosis lung disease that can be assessed in vivo using functional imaging methods. In this study we evaluated experimental factors affecting measurements of mucociliary clearance (MCC) and small-molecule absorption (ABS) and patient factors associated with abnormal absorption and mucus clearance.Our imaging technique utilises two radiopharmaceutical probes delivered by inhalation.

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Objectives/hypothesis: Preoperative localization for parathyroid disease has improved in recent years with the advent of dual-phase (99m) Tc-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) imaging. However, dual-phase imaging is associated with increased cost, time, and radiation dose. The aim of this study was to investigate the need for late-phase imaging when using SPECT/CT for the preoperative localization of parathyroid disease.

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Parathyromatosis is a rare clinical condition resulting in recurrent hyperparathyroidism that often poses challenges in its diagnosis and complete surgical cure. We report the (99m)Tc MIBI SPECT findings in a patient with recurrent hyperparathyroidism requiring multiple parathyroid explorations. MIBI SPECT helped localize the areas of these "recurrent parathyroid lesions" that were often found outside of the expected locations within the neck.

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Objective: To assess the clinical utility of SPECT/ CT in subjects with endocrine and neuroendocrine tumors compared to SPECT alone.

Material And Methods: 48 subjects (31 women;17 men; mean age 54±11) with clinical suspicion or diagnosis of endocrine and neuroendocrine tumor had 50 SPECT/CT scans (32 Tc-99m MIBI, 5 post treatment I-131, 8 In-111 Pentetreotide, and 5 I-123 MIBG). SPECT alone findings were compared to SPECT/CT and to pathology or radiological follow up.

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Cardiac metastases from renal cell carcinoma are rare but should be recognized when present. We report PET/CT findings in a patient with headache and diplopia and cerebral metastasis from an unknown primary of clear cell adenocarcinoma origin. PET/CT revealed uptake with a left renal cell carcinoma, and revealed multiple metastatic lesions, including an FDG-avid metastasis within the left ventricular myocardium.

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Objective: To report a case of intestinal malrotation predisposing to cecal volvulus following nonabdominal surgery in an adult.

Presentation And Intervention: A 23-year-old male with known anorectal malformation developed a postoperative intestinal obstruction following percutaneous nephrolithotomy for left renal calculus. Computed tomography of the abdomen revealed a grossly dilated cecum (9 cm) with ileocecal junction on the left side and small bowel loops on the right side of the abdomen.

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Introduction: The objective of the study was to identify the predictive factors for malignancy in pancreatic head mass as a primary outcome and assess the value of CA 19-9 as a diagnostic tool for malignancy as a secondary outcome.

Methods: A prospective study of patients presented with pancreatic head mass was conducted in a tertiary care referral hospital, Manipal, India from May 2006 to November 2008. The study population was divided into malignant and benign groups based on the final histopathology report.

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Recent studies have advocated the utility of fluorine-18 fluorodeoxyglucose-positron emission tomography (18)F-FDG-PET imaging in evaluation of various hematological disorders. We report a case of a 61-year-old man with clinical suspicion of post-transplant lymphoproliferative disorder (PTLD) where (18)F-FDG-PET/CT (computerized tomography) was helpful in identifying myelofibrosis. This paper aims to reveal the potential diagnostic value of PET/CT as an imaging modality in the evaluation of myelofibrosis.

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