Morphological and Metabolic Criteria of COVID-19 Vaccine Associated Axillary Nodes on 18-Fluorodeouxyglucose PET/CT Imaging in Breast Cancer Patients.

Background:  In the current era vaccine-associated lymphadenopathy (VAL) is not an uncommon presentation on 18F-FDG PET/CT examinations in patients inoculated with Coronavirus disease 2019 (COVID-19) vaccination. In this study, we are presenting data of VAL on 18F-FDG PET/CT regarding its prevalence, temporal response to vaccination and imaging characteristics of VAL.

Methods: Seventy-eight (78) consecutive vaccinated breast cancer (BC) patients who had 18FDG PET/CT were retrospectively analyzed.

Intense Fluorodeoxyglucose Uptake in Aggressive Systemic Mastocytosis without Associated Hematological Neoplasm: Unusual Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Presentation.

Systemic mastocytosis (SM) is a relatively rare heterogeneous group of disorders characterized by uncontrolled proliferation and accumulation of clonal mast cells in one or more organs. Indolent SM is the most common variety. Less common variety is aggressive systemic mastocytosis (aSM) type with or without associated hematological neopalsm (AHN).

Hyperammonemic Encephalopathy Secondary to Urinary Tract Infection.

Hyperammonemic encephalopathy (HE) refers to a clinical condition characterized by abrupt alteration in mental status (AMS) with markedly elevated plasma ammonia levels and frequently results in intractable coma and death. While hepatic cirrhosis is by far the most common etiology for hyperammonemia together with drugs such as valproic acid as well as urea cycle disorders, non-hepatic causes of hyperammonemia are rare and pose a clinical challenge. In this report, we describe a case of HE caused by obstructive urinary tract infection due to urease-producing bacteria in a 69-year-old man with two episodes of obstructive uropathy associated with AMS resolving with treatment with antibiotics and lactulose with normalization of ammonia level.

Impact of Primary Tumor Size, SUVmax of Primary Tumor and the Most Avid Neck Node on Baseline FDG PET/CT upon Disease Recurrence in Head and Neck Oropharyngeal SCC Using Standardized Imaging Protocol.

 The purpose fo this prospective study was to find the impact of primary tumor size (Ts), standardized uptake values (SUVmax) of primary tumor, and the most avid neck node on disease recurrence in patients with head and neck oropharyngeal squamous cell carcinoma (HNOP-SCC).  We included patients with HNOP-SCC (without distant metastasis-M0 disease) who had pre- and post-treatment F-18 fluorodeoxyglucose positron emission tomography/computed tomography ( FDG PET/CT) using strict standardized imaging protocol from 2017 to 2019. Based on follow-up ( FDG PET/CT) findings, patients were categorized as disease free (no or minimal FDG uptake ≤ background over surgical bed and no distant metastasis) and disease recurrence ( FDG uptake > background over surgical bed with or without nodal and/or distant metastasis).

Neurolymphomatosis - Rare presentation in non-Hodgkin's lymphoma: The role of F-fluorodeoxyglucose positron-emission tomography and computerized tomography imaging.

Neurolymphomatosis (NLS) is infiltration of lymphoma cells into the peripheral or cranial nervous system and is a rare manifestation of non-Hodgkin lymphoma (NHL). Nerve biopsy is considered as the gold standard for diagnosis but not a preferred choice, and magnetic resonance imaging has lower reported sensitivity. F-Fluorodeoxyglucose (FDG) positron-emission tomography and computerized tomography (PET/CT) has a higher sensitivity for diagnosing and assessing the neurological and nonneurological metabolic tumor volume and response evaluation to therapy.

Staging and Response Evaluation to Neo-Adjuvant Chemoradiation in Esophageal Cancers Using 18FDG PET/ CT with Standardized Protocol.

Background: Precise staging of esophageal cancer (EC) is important for selection of optimal treatment option and prognostication. Aim of this study was to assess the role of 18FDG PET/CT in staging and response evaluation to neoadjuvant chemoradiation (nCR) in EC patients using standardized imaging protocol. Material and methods: This prospective study was conducted at PET/CT Section of Department of Radiology, Aga Khan University Hospital Karachi, Pakistan from July 2017 till February 2018.

Pure Uterine Lipoma on 18FDG PET/CT: Rare But Easy to Diagnose.

Tumors of the uterus are extremely uncommon. Pure lipomas of the uterus are very rare, and only a few cases have been reported. We are presenting a case of a post-menopausal lady, a survivor of right breast cancer who had an 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) for evaluation of a suspected right lung nodule.

Higher event rate in patients with high-risk Duke Treadmill Score despite normal exercise-gated myocardial perfusion imaging.

This prospective study was carried out to find the negative predictive value of various Duke Treadmill Scores (DTSs) in patients with normal myocardial perfusion imaging (MPI). This study was conducted from August 2012 to July 2015, and 603 patients having normal exercise MPIs were included. Patients were followed for 2 years for fatal myocardial infarction (FMI) and nonfatal myocardial infarction (NFMI).

Massive Tumor Thrombus in Left Renal Vein and Inferior Vena Cava in Renal Cell Carcinoma on 18-fluorodeoxyglucose Positron Emission Tomography/computerized Tomography: "Suspension Bridge Sign".

Tumor thrombosis is a relatively uncommon complication of renal cell carcinoma (RCC), and its diagnosis has therapeutic and prognostic implication. Computerized tomography (CT) is the primary imaging modality for staging RCC, but it has low sensitivity to differentiate between tumor thrombus and bland or benign thrombus. 18-fluorodeoxyglucose positron emission tomography/CT (PET/CT) has a limited role in diagnosis and staging of RCC, but its diagnostic accuracy is considerably high for detection of metabolically active tumor thrombus.

Comparison of Hemodynamic Effects and Negative Predictive Value of Normal Adenosine Gated Myocardial Perfusion Scan With or Without Caffeine Abstinence.

For vasodilator stress, myocardial perfusion imaging (MPI) with at least 12-h caffeine abstinence is recommended, as it attenuates cardiovascular hyperemic response of adenosine and dipyridamole. However, many published conflicting results have shown no significant effect upon perfusion abnormalities in MPI performed without caffeine abstinence. The aim of this study was to compare the hemodynamic changes and negative predictive value (NPV) of normal MPIs with adenosine stress performed with or without caffeine abstinence.

Comparable Ablation Efficiency of 30 and 100 mCi of I-131 for Low to Intermediate Risk Thyroid Cancers Using Triple Negative Criteria.

Background: There is controversy about ablation efficacy of low or high doses of radioiodine-131 (RAI) in patients with differentiated thyroid cancers (DTC). The purpose of this prospective study was to determine efficacy of 30 mCi and 100 mCi of RAI to achieve successful ablation in patients with low to intermediate risk DTC.

Materials And Methods: This prospective cross sectional study was conducted from April 2013 to November 2015.

Factors Predicting Early Release of Thyroid Cancer Patients from the Isolation Room after Radioiodine-131 Treatment.

Background: Patients with differentiated thyroid cancers (DTC) who receive radioactive iodine-131 (RAI) are released from isolation when their dose rate is below the regulatory requirements. The purpose of this study was establish predicting factors for early release from the isolation facility after RAI administration in patients with DTC.

Materials And Methods: This was a prospective study which included 96 (58 females and 38 males) patients with DTC who had received RAI from April 2013 till August 2015.

Predictive value of pyramidal lobe, percentage thyroid uptake and age for ablation outcome after 15 mCi fixed dose of radioiodine-131 in Graves' disease.

Purpose: The purpose was to find out the efficacy of fixed 15 mCi radioactive iodine-131 (RAI) dose and predictive values of various factors for inducing hypothyroidism in Graves' disease (GD).

Materials And Methods: Retrospective study conducted from January 2012 till August 2014. Patients with GD who had a technetium-99m thyroid scan, thyroid antibodies, received fixed 15 mCi RAI and did follow endocrine clinics for at least 6 months were selected.

Hybrid Imaging in Oncology.

In oncology various imaging modalities play a crucial role in diagnosis, staging, restaging, treatment monitoring and follow up of various cancers. Stand-alone morphological imaging like computerized tomography (CT) and magnetic resonance imaging (MRI) provide a high magnitude of anatomical details about the tumor but are relatively dumb about tumor physiology. Stand-alone functional imaging like positron emission tomography (PET) and single photon emission tomography (SPECT) are rich in functional information but provide little insight into tumor morphology.

Temporal trends in results of 9170 myocardial perfusion imaging studies (2004 to 2013).

Background: To assess the frequency of normal and abnormal myocardial perfusion imaging (MPI) in a consecutive cohort of patients from Pakistan over a period of 8.5 years.

Material And Methods: We assessed 9170 patients who had undergone stress-rest MPI between January 2004 and June 2013.

"Pseudo-thyroid lobe": A diagnostic conundrum caused by ossified anterior longitudinal ligament on bone scan.

Radionuclide bone imaging is one of the most commonly performed nuclear medicine procedure around the world and characterized by its high sensitivity and relatively low specificity. False positive findings on a bone scan are very common; however, dense uptake over unilateral ossified anterior longitudinal ligament appearing as single thyroid lobe on a bone scan has not been described in the literature.

18FDG synthesis and supply: a journey from existing centralized to future decentralized models.

Positron emission tomography (PET) as the functional component of current hybrid imaging (like PET/ CT or PET/MRI) seems to dominate the horizon of medical imaging in coming decades. 18Flourodeoxyglucose (18FDG) is the most commonly used probe in oncology and also in cardiology and neurology around the globe. However, the major capital cost and exorbitant running expenditure of low to medium energy cyclotrons (about 20 MeV) and radiochemistry units are the seminal reasons of low number of cyclotrons but mushroom growth pattern of PET scanners.

Baseline stimulated thyroglobulin level as a good predictor of successful ablation after adjuvant radioiodine treatment for differentiated thyroid cancers.

Background: To determine the predictive value of the baseline stimulated thyroglobulin (STg) level for ablation outcome in patients undergoing adjuvant remnant radioiodine ablation (RRA) for differentiated thyroid carcinoma (DTC).

Materials And Methods: This retrospective study accrued 64 patients (23 male and 41 female; mean age of 40±14 years) who had total thyroidectomy followed by RRA for DTC from January 2012 till April 2014. Patients with positive anti-Tg antibodies and distant metastasis on post-ablative whole body iodine scans (TWBIS) were excluded.