Krishan Kant Agarwal

Metastatic poorly differentiated prostatic carcinoma with neuroendocrine differentiation: negative on 68Ga-PSMA PET/CT.

Glu-NH-CO-NH-Lys-(Ahx)-[Ga-68(HBED-CC)], abbreviated as Ga-PSMA, is a novel radiotracer undergoing evaluation for PET/CT imaging of prostate carcinoma. Its major advantage is the sensitive detection of lesions even at low prostate-specific antigen level and high target-to-background ratios obtained in metastatic lesions, which is better than that obtained with F-fluoromethylcholine. We present the case of a 28-year-old man with poorly differentiated prostate carcinoma with neuroendocrine differentiation, whose lesions did not show significant Ga-PSMA localization. As literature on utility of Ga-PSMA PET/CT for imaging prostate carcinoma grows, it is important to be aware of potential false negatives that could influence study results.

A Rare Case of Non–small Cell Lung Cancer Metastasizing to the Pituitary Gland: Detection With 18f-fdg Pet-ct

Metastases to the pituitary gland are rare. We here present a case of a 52-year-old man with non-small cell lung cancer where pituitary metastasis was detected on staging F-FDG PET-CT, characterized with MRI and confirmed at histopathology. By demonstrating such rare site of metastasis, F-FDG PET-CT can have significant impact on management of cancer patients.

Metastatic neuroendocrine carcinoma presenting as a "Superscan" on 68Ga-DOTANOC somatostatin receptor PET/CT.

PET/CT imaging using Ga-labeled somatostatin analogs has become a popular noninvasive diagnostic modality in the workup of patients with neuroendocrine tumors. A 65-year-old man with pancreatic neuroendocrine tumor with confirmed liver metastases on conventional imaging underwent restaging Ga-DOTANOC PET/CT to monitor response to cold octreotide therapy. Previous PET/CT had shown presence of multiple liver and skeletal metastases along with a primary pancreatic tumor showing intense tracer uptake. The present PET/CT study showed an increase in number and uptake of the metastatic lesions suggestive of progressive disease resulting in the appearance of a superscan.

Incremental value of 99mTc-MDP hybrid SPECT/CT over planar scintigraphy and SPECT in avascular necrosis of the femoral head.

ObjectiveThe aim of the study was to evaluate the incremental value of technetium-99m-methylene diphosphonate (99mTc-MDP) single-photon emission tomography/computed tomography (SPECT/CT) over planar bone scintigraphy (BS) and SPECT in the diagnosis of avascular necrosis (AVN) of the femoral head. Materials and methodsThe data of 44 patients (mean age 36±16 years, 34 male and 10 female) who underwent 99mTc-MDP BS along with regional SPECT/CT for suspected femoral head AVN were retrospectively evaluated. Planar BS, SPECT and SPECT/CT images were evaluated by two nuclear medicine physicians in consensus. On the basis of diagnostic confidence, a score of 1–5 was given, with 1 being definitely AVN, 2 being probably AVN, 3 being equivocal, 4 being probably normal and 5 being definitely normal. Receiver operating characteristic analysis was performed and the area under the curve was calculated. For calculation of sensitivity, specificity and predictive values for planar, an interpretive score of less than or equal to 2 was taken as AVN and a score of 3 or more was taken as no AVN. Clinical and imaging follow-up and histopathological results were taken as the reference standard. ResultsAmong 44 patients with 64 affected femoral heads, there were 48 true-positive, 13 true-negative, two false-positive and one false-negative lesion on SPECT/CT. The diagnostic accuracy of planar BS, SPECT and SPECT/CT was 67, 78 and 95%, respectively. Planar BS was found to have the lowest sensitivity (75%) and specificity (40%), whereas SPECT/CT had the highest sensitivity (98%) and specificity (87%). The area under the curve was highest for SPECT/CT (0.919), followed by SPECT (0.76) and planar BS (0.567). SPECT/CT was superior to both SPECT (P=0.02) and planar BS (P<0.001), whereas SPECT was superior to planar BS (P=0.03). ConclusionSPECT/CT is superior to planar BS and SPECT alone for the diagnosis of AVN of the femoral head.

Utility of 99m Tc-MDP SPECT-CT for the diagnosis of sesamoiditis as cause of metatarsalgia

Metatarsalgia is a general term for pain in the area of the metatarsophalangeal joints. Sesamoiditis is an uncommon cause of metatarsalgia. It is pain at the sesamoid bones beneath the head of the first metatarsal with inflammation or fracture. The diagnosis is usually clinical, with localized tenderness on palpation. Diagnosing the cause of metatarsalgia in patients without this classical sign is difficult. We present here such a case of a 37-year-old lady in whom sesamoiditis was diagnosed with technetium-99m (99mTc)-methylene diphosphonate (MDP) single photon emission tomography-computed tomography (SPECT-CT).

Diuretic 18F-Fluorodeoxyglucose PET/Computed Tomography in Evaluation of Genitourinary Malignancies

The interpretation of fluorodeoxyglucose (FDG) PET/computed tomography (CT) is often challenging for pelvic pathologies because of the physiologic bowel and urinary tract activity. Intense radiotracer activity in urinary tract interferes in image interpretation and leads to false-negative results in diagnosis and detection of local recurrence and regional lymph node metastases. It is imperative to minimize unnecessary urinary bladder activity to improve the diagnostic yield of PET/CT. All the techniques described in the literature have their pros and cons. This article discusses FDG PET/CT in evaluation of urinary bladder cancer, cervical cancer, and ovarian cancer.

Incremental value of single photon emission tomography/computed tomography in 3-phase bone scintigraphy of an accessory navicular bone

Accessory navicular bone is one of the supernumerary ossicles in the foot. Radiography is non diagnostic in symptomatic cases. Accessory navicular has been reported as a cause of foot pain and is usually associated with flat foot. Increased radio tracer uptake on bone scan is found to be more sensitive. We report a case highlighting the significance of single photon emission tomography/computed tomography in methylene diphosphonate bone scan in the evaluation of symptomatic accessory navicular bone where three phase bone scan is equivocal.

Incremental value of single-photon emission computed tomography/computed tomography in the diagnosis of active condylar hyperplasia.

Objective To evaluate the incremental value of technetium-99m methylene diphosphonate (99mTc-MDP) single-photon emission computed tomography/computed tomography (SPECT/CT) over planar bone scintigraphy (BS) and SPECT for the diagnosis of active condylar hyperplasia (CH). Patients and methods Data of 21 patients (mean age: 21.9±5.3 years, 10 males, 11 females) who underwent 99mTc-MDP BS along with regional SPECT/CT for the diagnosis of active CH were retrospectively evaluated. Planar BS, SPECT, and SPECT/CT images were evaluated by two nuclear medicine physician in consensus. Radioactive counts were measured per region of interest and the respective ratios were calculated. A percentage of condylar uptake 55% or higher, generating differences of 10% or more between condyles, was considered to be indicative of active unilateral condylar hyperactivity. Sensitivity, specificity, and positive and negative predictive values were calculated separately for planar BS, SPECT, and SPECT/CT. Clinical/imaging follow-up and histopathology was considered the reference standard. Results Planar BS, SPECT, and SPECT-CT of 21 patients with suspected CH were retrospectively evaluated. Planar BS was positive in eight patients, of whom six had active CH as the final diagnosis. SPECT was positive in 14 patients, of whom 12 patients had CH. Out of 14 patients who were positive in SPECT, two patients were considered negative in SPECT-CT. The diagnostic accuracy was the lowest for planar BS (47.6%) and the highest for SPECT/CT (85.8%). SPECT/CT and SPECT had similar sensitivity (80%), whereas SPECT-CT had the highest specificity (100%). Conclusion SPECT/CT is superior to planar BS and SPECT for the diagnosis of active CH.

18F-Fluorodeoxyglucose PET/CT in Langerhans cell histiocytosis: spectrum of manifestations

The objective of this article is to provide an illustrative tutorial highlighting the utility of 18F-FDG PET/CT imaging to detect the spectrum of manifestations in patients with Langerhans cell histiocytosis. FDG PET/CT is a powerful tool for making an early diagnosis; it allows higher diagnostic confidence with regard to lesions, measuring the extent of disease (staging) and assessing disease activity, and is consequently useful for evaluating the response to therapy in patients with Langerhans cell histiocytosis.

Primary pulmonary lymphoma-role of fluoro-deoxy-glucose positron emission tomography-computed tomography in the initial staging and evaluating response to treatment - case reports and review of literature

Primary pulmonary lymphoma (PPL) is an uncommon entity of non-Hodgkin lymphoma, which accounts for <1% of all cases of lymphoma. We present two rare cases of PPL of diffuse large B-cell lymphoma, which underwent 18fluorine fluoro-deoxy-glucose positron emission tomography-computed tomography for initial staging and response evaluation after chemotherapy.