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Stress insufficiency fracture is usually diagnosed clinically and on the basis of routine X-ray imaging findings. However, the absence of any known predisposing factors and negative or occult radiographic findings pose diagnostic challenges. We report the case of an elderly male patient who presented with a chief complaint of trivial left hip pain and with equivocal radiographic findings. Triphasic 99mTc-methylene diphosphonate bone scan and single-photon emission computed tomography/computed tomography helped in arriving at the diagnosis of stress insufficiency fracture involving femoral neck. [ABSTRACT FROM AUTHOR]

Introduction: Targeted therapeutic agents are indicated in metastatic lung cancers. These being receptor specific · · M I Ä B M * * ! therapies, manifestation of response can be best assessed by estimating the metabolic activity of tumor, rather than the size. This retrospective analysis studied metabolic and morphological response on Positron Emission Tomography (PET) and Computed Tomography (CT), respectively to these agents. Materials and Methods: Thirty-one patients (23 males, 8 females with an age range of 42-77 years) with Epidermal Growth Factor Receptor (EGFR) positive metastatic lung cancer on Gefitinib, who underwent PET/CT, at baseline and at 4 -6 weeks, were assessed by Response Evaluation Criteria In Solid Tumors [RECIST] 1.1 and European Organization for Research and Treatment of Cancer (EORTC) criteria. Results: Concordance between RECIST 1.1 and EORTC was seen in 26 (83.7%) patients. Discordance was seen in 5 (16.3%) patients. In patients with discordance, the results were confirmed by follow-up imaging. Metabolic EORTC criteria changed the disease status from stable disease to partial response (3 out of 5) and progressive disease (2 out of 5) in these five patients. Conclusions: Metabolic criteria using PET/CT could accurately predict response as well as disease progression early in the course of targeted therapy, compared to morphologic criteria. In addition, early metabolic response assessment can predict refractoriness of therapy [ABSTRACT FROM AUTHOR]

Majority of patients with head and neck cancer are treated with combined treatment regimes such as surgery, radiation therapy, and chemotherapy. The loss of structural symmetry and imaging landmarks as a result of therapy makes post-treatment imaging a daunting task on conventional modalities like computed tomography (CT) scan and magnetic resonance imaging (MRI) as well as on 18 Fluorine-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F FDG PET/CT). Combined multimodality treatment approach causes various tissue changes that give rise to a spectrum of findings on FDG PET/CT imaging, which are depicted in this atlas along with a few commonly encountered imaging pitfalls. The incremental value of FDG PET/CT in detecting locoregional recurrences in the neck as well as distant failures has also been demonstrated. [ABSTRACT FROM AUTHOR]

Nonspecific uptake of prostate-specific membrane antigen (PSMA) on PSMA positron-emission tomography/computed tomography (CT) is normally encountered in benign conditions, which is detected on morphological changes on CT component. However, having a site of uptake without any CT finding is a rare occurrence. We herewith report one such rare case of a 66-year-old male with metastatic prostatic adenocarcinoma, who demonstrated an incidental finding of intense focal PSMA uptake in the lung parenchyma. [ABSTRACT FROM AUTHOR]

Chondroblastic osteosarcoma is an uncommon subtype of osteosarcoma, constituting about 25% of all osteosarcoma cases. It has shown high propensity for developing tumor thrombi and thromboembolism, with poor overall survival rate. Differentiation between tumor thrombus and bland thrombus is an important factor in making treatment decisions. 18 F fluorodeoxyglucose positron emission tomography/computed tomography plays a very important role in detecting and differentiating bland thrombus from tumor thrombus. [ABSTRACT FROM AUTHOR]

Aim: The study aimed at developing a scoring system for scintigraphic grading of gastro-esophageal reflux (GER), on gastro-esophageal reflux scintigraphy (GERS) and comparison of clinical and scintigraphic scores, pre- and post-treatment. Materials and Methods: A total of 39 cases with clinically symptomatic GER underwent 99mTc sulfur colloid GERS; scores were assigned based on the clinical and scintigraphic parameters. Post domperidone GERS was performed after completion of treatment. Follow up GERS was performed and clinical and scintigraphic parameters were compared with baseline parameters. Results: Paired t-test on pre and post domperidone treatment clinical scores showed that the decline in post-treatment scores was highly significant, with P value < 0.001. The scintigraphic scoring system had a sensitivity of 93.9% in assessing treatment response to domperidone, specificity of 83.3% i.e., 83.3% of children with no decline in scintigraphic scores show no clinical response to Domperidone. The scintigraphic scoring system had a positive predictive value of 96.9% and a negative predictive value of 71.4%. Conclusion: GERS with its quantitative parameters is a good investigation for assessing the severity of reflux and also for following children post-treatment. [ABSTRACT FROM AUTHOR]

Autism is a neurodevelopmental disorder with multifactorial etiology and varied presentation, in which early diagnosis is crucial to the implementation of early treatment. A 6-year-old child clinically diagnosed with autism, and a normal magnetic resonance imaging underwent dedicated 18F-fluorodeoxyglucose brain positron emission tomography (PET) as an ancillary investigation. PET image showed diffuse bilateral temporal hypometabolism. Although PET imaging is currently not indicated in the evaluation of autism, characteristic imaging patterns on PET can provide corroborative information and increase the diagnostic confidence for the same. [ABSTRACT FROM AUTHOR]

Sclerotic bone dysplasias are diagnosed based on clinical and radiological features; however, in some instances pose a dilemma. We herewith report a case of a 38-year-old female who presented with right lower extremity pain, and was detected to have sclerotic diaphyseal lesion on X-ray. Triphasic 99mTc methylene diphosphonate (MDP) Bone scan helped in confirming the diagnosis of intramedullary osteosclerosis, a dysplastic bone disorder. [ABSTRACT FROM AUTHOR]

Multi-modality positron emission tomography/computed tomography (PET/CT) with 18F-fluoro-deoxy-glucose (FDG) depicts the enhancement pattern and metabolic intensity of lesions. Benign lesions with multiplicity, like neurofibromas often mimic similar appearing malignant neoplasms. We, report, a similar case where FDG PET/CT shows imaging hallmarks for diagnosing benign neurofibromas, in a patient with clinical presentation of lymphoma. [ABSTRACT FROM AUTHOR]

Finding of focal 18F-fluoro-deoxyglucose (FDG) uptake in liver on FDG positron emission tomography/computed tomography (FDG PET/CT) in a known case of malignancy is often considered to be metastases. We report a similar finding on FDG PET/CT in a case of Ewing's sarcoma of thigh, which turned out to be of tuberculous etiology, an unusual cause of false positive FDG uptake in the liver. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article related to unilateral vocal cord paralysis.

A letter to the editor is presented related to a 61-year-old man suffering from oral cavity cancer who was diagnosed with multiple skip lesions in oropharynx and contralateral synchronous primary in hypopharynx following a fluorodeoxyglucose (FDG) positron emission tomography.

Area of fat sparing in fatty liver is known to pose a diagnostic challenge in an oncological setting, especially in cancers with higher propensity for liver metastases. We report an unusual appearance of hepatic metastases in a fat spared area, on both computed tomography (CT) and positron emission tomography (PET), in a combined 18 fluorine-fluorodeoxyglucose (18 F-FDG) PET/CT study done in metastatic adenocarcinoma of colon. [ABSTRACT FROM AUTHOR]

Bone metastases from recurrent cervical cancer is a rare scenario, with commonly involved sites being lumbar spine and pelvic bones report an extremely rare manifestation of cervical cancer recurrence presenting as a painful jaw swelling due to metastasis to the mandibular condyle. [ABSTRACT FROM AUTHOR]

Gall bladder (GB) duplication is a rare condition often found incidentally; most of these detected on screening Ultrasonography (USG) for abdominal colic. Nuclear hepatobiliary scan, popularly known as hepatobiliary iminodiacetic acid (HIDA) scan, with its biliary kinetics, is highly specific for picking up abnormalities related to biliary tract and GB. We report two cases of duplication of GB visualized on HIDA scan. First case highlights the role of HIDA scan in diagnosis of duplicated GB, where USG was equivocal with a number of differentials, whereas in the second case, HIDA helped to rule out obstruction in this case of duplicated GB identified on USG; ruling out biliary cause for the abdominal colic. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding the case study of a 40-year-old female who was diagnosed with extra-renal malignant rhabdoid tumour (MRT) of head and neck region.

Artifacts present in computed tomography (CT) image often degrade the image quality and ultimately, the diagnostic outcome. Ring artifact in trans-axial image is caused by either miscalibrated or defective detector element of detector row, which is often categorized as scanner based artifact. A ring artifact detected on trans-axial CT image of positron emission tomography/computed tomography (PET/CT), was caused by contamination of CT tube aperture by droplet of injectable contrast medium. This artifact was corrected by removal of contrast droplet from CT tube aperture. The ring artifact is a very common artifact, commonly cited in the literature. Our case puts forward an uncommon cause of this artifact and its method of correction, which also, has no mention in the existing literature. [ABSTRACT FROM AUTHOR]

Sinister undesirable pathologies often accompany malignancies. Though the entire emphasis is on cancer management, these benign conditions are more life-threatening than the primary malignancy itself. We report an interesting imaging finding of broncho-esophageal fistula leading to lung abscess on 18F- fluoro-deoxy-glucose positron emission tomography/computed tomography (FDG PET/CT) in large middle esophageal cancer, which due to early detection, was promptly managed. [ABSTRACT FROM AUTHOR]

A letter to the editor related to a case study of a 64-year-old gentleman was diagnose with fluorodeoxyglucose positron emission tomography/computed tomography (FDG) PET/CT for radiotherapy treated laryngeal cancer.

Reconstruction artifacts often affect the image quality. An unusual wavy imaging pattern was seen on computed tomography (CT) part of positron emission tomography/CT, on sagittal and coronal images. This pattern was corrected on realignment of CT tube. This artifact, popularly known as stair step artifact, is rarely cited in the literature and our case generates a practical scenario of how it affects the image quality and how it is corrected. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article related to multicentric Castleman's disease that was published in the previous issue.

Autoimmune pancreatitis (AIP) is most often incidentally detected, with the diagnosis being based on radiological characteristics. A steroid regimen for 6 weeks is the standard line of treatment for AIP. In our case, AIP was incidentally suspected on fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) performed for staging a malignancy, and a follow-up PET/CT study after steroid treatment, showed complete metabolic and morphological response; thus confirming the imaging diagnosis of AIP. [ABSTRACT FROM AUTHOR]

Scenario such as uptake of Fluoro-deoxyglucose (FDG) with no corresponding abnormality on computed tomography (CT) is encountered in case of brown fat uptake. However, it is rarely encountered in the lung parenchyma. We report one such case of a focal FDG uptake in the lung parenchyma with no corresponding CT abnormality, in a treated case of hypopharyngeal cancer. [ABSTRACT FROM AUTHOR]

Unexpected findings are seen on FDG PET/CT outside the primary site of abnormality. Such incidental findings are common in the genitourinary tract due to normal urinary excretion of FDG. We report a case of incidentally detected grade 3 cystocele in a patient who underwent FDG PET/CT study for a suspected lung malignancy. [ABSTRACT FROM AUTHOR]

Dual left anterior descending artery (LAD) is a rare variation in the coronary artery anatomy having 4 different subtypes. We report a rare scenario of type IV dual LAD, with short LAD critical stenosis, compensated by a long LAD perfusing the same territory, which was missed on initial angiographic evaluation. Myocardial perfusion scan (MPS) of this patient showed preserved perfusion. A review of angiogram revealed this anomaly, indicating that a meticulous correlation of anatomic and functional modalities is necessary as it could change further management of patient. [ABSTRACT FROM AUTHOR]

Diffuse midline glioma, H3 K27-altered is a rare and aggressive pediatric brain tumor with a grim prognosis. Diffuse midline glioma is characterized by specific molecular alterations, including H3 K27 mutations, and involves deep midline structures such as the brainstem, cerebellum, spinal cord, and thalamus. These tumors present with a classic triad of symptoms and have limited surgical options due to their challenging locations. Extra-neural metastases are an unusual occurrence in diffuse midline glioma and have been rarely described. Here we report a 17-year-old girl with spinal diffuse midline glioma, H3 K27M-mutant, who presented with multiple metastatic osseous lesions confirmed on biopsy of the thoracic vertebral lesion. Due to the rapid disease progression, the patient was recommended palliative therapy. Extra-neural metastases in diffuse midline glioma are rare, with only 16 reported patients, and no standard therapy exists. An accurate and early diagnosis is necessary to develop a personalized plan of treatment. Further research is needed to gain insights into the molecular pathology of diffuse midline glioma, H3 K27-altered, and improve the quality of life and the outcome of patients with this deadly disease. [ABSTRACT FROM AUTHOR]

Fibroblast-activated protein (FAP) expression in glial cells is attributed to FAP-positive foci on tumor vessels and neoplastic cells. Preclinical and pilot studies have shown FAP expression in high-grade gliomas. We aimed at comparing PET imaging with FAP-inhibitor (FAPI-PET) with current standard, i.e., fluoro-ethyl tyrosine (FET) PET in post-treatment setting to differentiate recurrence and post-treatment changes. 6 patients with WHO Grade III and IV glioma who received standard treatment underwent Ga-68-FAPI-04 PET/CT (FAPI-PET/CT). Tracer uptake greater than background was considered positive. FET PET was performed and interpreted as per institutional standards, which formed the basis of treatment decision. There was concordance between FAPI expression and FET uptake in 5 patients suggestive of disease recurrence. There was no FAPI expression seen in 1 patient, in whom FET PET was suggestive of post-treatment changes. FAPI PET uptake correlated with amino acid expression to differentiate post treatment changes from recurrence in high-grade glial tumors; further validation with prospective study and histopathological confirmation is needed., Competing Interests: The authors declare that they have no conflicts of interest., (© The Author(s) 2024.)

National Electrical Manufacturers Association (NEMA) provides guidelines to assess the performance of Positron Emission Tomography (PET). A PET/CT scanner, Discovery IQ, GE Medical systems, Milwaukee, USA was installed in our department which has high a sensitivity PET component. We have performed the NEMA NU-2 2012 quality control tests to evaluate this system on site before clinical use. Performance measurements of the PET scanner were made using the NEMA NU2-2012 procedures for spatial resolution, scatter fraction, sensitivity, count rate loss and random coincidence estimation, Noise Equivalent Count Rate (NECR) and image quality. As per NU2 2012, spatial resolution was measured at 1 cm, 10 cm and 20 cm vertically from the centre and at each of these points resolution was measured at tangential, radial and axial directions. Sensitivity was measured at centre and 10 cm off center vertically from the center. The system sensitivity is reported as an average of the two measured values. Scatter fraction and NECR measurements, Image quality test was also performed. The tangential, radial and axial FWHM were 4.99 mm, 4.20 mm and 4.79 mm at 1 cm off centre, 5.49 mm, 4.69 mm and 4.81 mm at 10 cm off centre and 7.99 mm, 5.07 mm and 4.95 mm at 20 cm off centre respectively. The absolute sensitivity of this scanner was found to be 20.1 cps/kBq. The scatter fraction calculated from the decay method was 37.94% and NECR was 125 kcps. The peak NECR was achieved at activity concentration of 8.7 KBq/ml and the count loss below the peak NECR was found to be 0.68%. Image quality test for, contrast recovery, background variability and lung error residual mean met all specifications. Overall PET performance of Discovery IQ whole-body scanner was satisfactory and the scanner met all the performance specifications required by NEMA 2012., Competing Interests: There are no conflicts of interest., (Copyright: © 2019 World Journal of Nuclear Medicine.)