Girish Kumar Parida

Metabolic Skeletal Superscan on 18F-FDG PET/CT in a Case of Acute Lymphoblastic Leukemia.

Superscan is a well-known finding described in skeletal scintigraphy characterized by intense radiotracer uptake in axial skeleton and decreased uptake in soft tissues and kidneys. Metabolic skeletal superscan has also been described in ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in various conditions. We describe here a case of 12-year-old boy who presented with a scalp swelling, progressive pallor, easy fatigability, poor appetite, and fever for 6 months. The initial diagnosis was inconclusive. ¹⁸F-FDG PET/CT revealed metabolic skeletal superscan and the final histopathological diagnosis was acute lymphoblastic leukemia.

In Vivo Demonstration of PSMA Expression in Adenocarcinoma Urinary Bladder Using 68Ga-PSMA 11 PET/CT

In vitro and in vivo studies have demonstrated prostate-specific membrane antigen (PSMA) expression in various malignant and benign tumors. Based on the recent immunohistochemical study showing PSMA expression in adenocarcinoma of urinary bladder, we hypothesized that PSMA expression in adenocarcinoma of urinary bladder can be demonstrated in vivo using Ga-PSMA 11 PET/CT. We present a man with exstrophy bladder, presenting with adenocarcinoma urinary bladder referred for staging PET/CT. Both F-FDG and Ga-PSMA-11 PET/CT were done, which showed PSMA expression in the primary tumor as well as metastatic lymph nodes.

FDG-PET/CT in Skeletal Muscle: Pitfalls and Pathologies

FDG-PET/CT is an integral part of modern-day practice of medicine. By detecting increased cellular metabolism, FDG-PET/CT can help us detect infection, inflammatory disorders, or tumors, and also help us in prognostication of patients. However, one of the most important challenges is to correctly differentiate the abnormal uptake that is potentially pathologic from the physiological uptake. So while interpreting a PET/CT, one must be aware of normal biodistribution and different physiological variants of FDG uptake. Skeletal muscles constitute a large part of our body mass and one of the major users of glucose. Naturally, they are often the site of increased FDG uptake in a PET study. We as a nuclear medicine physician must be aware of all the pitfalls of increased skeletal muscle uptake to differentiate between physiological and pathologic causes. In this review, we have discussed the different causes and patterns of physiological FDG uptake in skeletal muscles. This knowledge of normal physiological variants of FDG uptake in the skeletal muscles is essential for differentiating pathologic uptake from the physiological ones. Also, we reviewed the role of FDG-PET/CT in various benign and malignant diseases involving skeletal muscle.

FDG PET/CT in Carcinoma of the Tongue With Bilateral Adrenal Metastases

Squamous cell carcinoma is the most common malignant neoplasm of the oral cavity, and it contributes approximately 90% of all oral malignancies. We present a case of a squamous cell carcinoma of the tongue with rare site of bilateral adrenal metastases on F-FDG PET/CT with response evaluation after chemotherapy.

Objective improvement in renal function post-Dietl's crisis: Documented on renal dynamic scintigraphy.

Dietls crisis is one of the treatable causes of intermittent abdominal pain. The pain is due to acute hydronephrosis that leads to stretching of the pelvis. The most common cause of this intermittent hydronephrosis is aberrant renal vessel at lower pole that causes pelvi-ureteric junction obstruction.(PUJO). High insertion of the ureter is one of the other rare causes. We present a case of 5-year-old boy with intermittent abdominal pain and distension with ultrasonography features of gross left hydronephrosis. Renal dynamic scan.(RDS) with ethylene dicysteine showed negligible functioning left kidney. On third follow-up day, the patient passed a lot of urine with decrease in abdominal pain and distension. Then, again the patient was sent to us 8.days after the first study for repeat RDS, which showed significant improvement in function and decreased in the size of left kidney though with persistent PUJO. On exploration high insertion of the ureter at pelvis was found to be the cause and was treated.

Pheochromocytoma presenting with remote bony recurrence twenty years after initial surgery: detection with 68Ga-DOTANOC PET/CT.

Pheochromocytomas are rare tumors which can be malignant in 10% of cases. We present the case of a 75-year-old woman who presented with headache and palpitation for 1 year. She had a past history of right adrenalectomy for pheochromocytoma 20 years back. In between, the patient was asymptomatic. Twenty-four-hour urinary vanillylmandelic acid was raised. Noncontrast CT and ultrasound of abdomen were unremarkable. The patient underwent 68Ga-DOTANOC PET/CT that showed metastasis to left ilium, which was confirmed on biopsy.

Pulmonary amyloidosis in a patient with Langerhans cell histiocytosis: diagnostic dilemma on 18F-FDG PET/CT.

Amyloidosis associated with Langerhans cell histiocytosis (LCH) is extremely rare. We here present the 18F-FDG PET/CT images of a 48-year-old male patient with multifocal skeletal involvement of LCH. In addition, he had a left lung upper lobe 18F-FDG avid mass that was misinterpreted as pulmonary involvement of LCH on PET/CT. Biopsy from the mass showed amyloidosis. Therefore, amyloidosis should be kept as a differential for 18F-FDG pulmonary avid nodule.

Quantitative Assessment of Gynecologic Malignancies

18F-fluorodeoxyglucose PET/CT as a dual-modality imaging, plays a key role in the diagnosis, staging, response assessment, and disease surveillance. Uptake by tumor cells offers an opportunity to differentiate viable malignant cells from posttreatment effects. 18F-fluorodeoxyglucose PET/CT-based criteria have been developed to evaluate treatment response. Uptake can reflect the biologic aggressiveness of the tumor, predicting the risk of metastasis and recurrence. The standardized uptake value can be measured as maximum, mean, or peak. Volumetric uptake measurements have shown substantial promise in providing accurate tumor assessment. We discuss these quantitative parameters in the assessment of gynecologic malignancies.

Detection of thymoma on 99mtc mibi scintigraphy: Revisiting the past

Although thymoma is a rare tumor, it is the most common anterior mediastinal tumor, usually affecting the adults in their fifth and sixth decade. We present a case of 68-year-old man with history of myocardial infarction, who presented to the cardiology OPD with recent onset of exertional dyspnea. On 99mTc MIBI myocardial perfusion SPECT, there was an extra cardiac accumulation of radiotracer in the anterior mediastinum just above the heart, which later was diagnosed as thymoma on histopathology.

Active Leprosy Neuritis Detected on FDG PET/CT

Uses of FDG PET/CT have been previously documented in multiple series in peripheral nerve pathologies, including neurolymphomatosis, peripheral nerve sheath tumor, and plexopathies. We present the case of a 24-year-old man with leprosy neuritis who underwent FDG PET/CT. We suggest that FDG PET/CT can be used as an adjunct tool to monitor neuritis in leprosy patients.