Indian Journal of Nuclear Medicine最新文献

Primary central nervous system lymphoma (PCNSL) is a rare, aggressive variant of extranodal non-Hodgkin's lymphoma. Although gadolinium-enhanced magnetic resonance imaging remains the initial imaging modality of choice, a whole-body F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is imperative to exclude systemic lymphomatous involvement. Furthermore, the metabolic parameter, maximum standardized uptake value (SUV_max) of the lesion, tumor-to-normal cerebral tissue SUV_max ratio, and FDG uptake patterns help in differentiating intracranial lymphomas from High-grade Glioblastoma Multiforme (HGM) and infectious lesions, and hence, consolidating the diagnosis. In this pictorial essay, we present a series of PCNSL cases, representing the different imaging characteristics and metabolic uptake patterns.

Thyroid gland metastases from nonthyroidal malignancies are extremely rare. The most common primary malignancies associated with metastasis to thyroid gland include renal cell carcinoma, colorectal carcinoma, lung cancer, and breast cancer. Metastasis to thyroid rarely arises from primary laryngeal cancer. The presence of metastasis to thyroid gland is invariable and associated with poor prognosis and thus, should be differentiated from primary thyroid malignancy. Hereby, we have one such case of metastasis to thyroid gland from laryngeal cancer diagnosed on 18F-fluorodeoxyglucose positron emission tomography/computed tomography scan.

Avascular necrosis (AVN) of the femoral head is a condition characterized by limited mobility, discomfort, and changes in walking patterns due to insufficient blood supply in this region. Our objective is to investigate the possible connection between COVID-19 and AVN. In this study, we detail the case of a 41-year-old male patient who developed AVN in both femoral heads after contracting COVID-19. The mere occurrence of a COVID-19 infection and the use of corticosteroids for its treatment may increase the probability of AVN in the femoral head. Hence, post the COVID-19 pandemic, it is crucial to consider AVN vigilantly for timely detection and treatment.

Objective: Biochemical recurrence (BCR) after initial management of Prostate Carcinoma (PC) is frequent. Subsequent interventions rely on disease burden and metastasis distribution. ⁶⁸Ga prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) is an excellent imaging modality in BCR. However, ⁶⁸Ga is radionuclide generator produced and has restricted availability. ⁹⁹mTc-labeled PSMA could be a potential cost-effective alternative. We compared the performance of ^99mTc-PSMA single-photon emission CT (SPECT)/CT and ⁶⁸Ga-PSMA PET/CT in BCR with a serum prostate surface antigen (PSA) level of <20 ng/mL.

Materials and methods: The prospective study included 25 patients with BCR and at least one lesion on a ⁶⁸Ga-PSMA PET/CT. All patients underwent 99 mTc-PSMA SPECT/CT, and disease distribution and metastatic burden were compared with ⁶⁸Ga-PSMA PET/CT. The maximum standard uptake value (SUVmax) and the tumor-to-background ratio (TBR) were computed and analyzed.

Results: The mean age and serum PSA (SPSA) were 69.72 ± 6.69 years and 5.65 ± 6.07 ng/mL. Eleven patients (44%) had SPSA ≤2 ng/mL. Recurrent sites were noted in the prostate (19, 76%), prostatic bed (3, 12%), and pelvis lymph nodes (LNs) (13, 52%). Distant metastasis to bones (13, 52%), lungs (5, 20%), and retroperitoneal LNs (2, 8%) were noted. Both modalities were concordant for the recurrent disease at the prostate, prostatic bed, bone, and lung lesions. ^99mTc-PSMA could localize pelvis LNs in most patients (10/13, 76.9%). The site-specific sensitivity and specificity between the two modalities were not significantly different (P > 0.05). TBR shows excellent correlation with SUVmax (0.783, P < 0.001). Four (16%) patients were understaged with ^99mTc-PSMA due to the nonvisualization of the subcentimeter size LNs. No patient with systemic metastases was understaged.

Conclusions: ^99mTc-PSMA SPECT/CT has good concordance with ⁶⁸Ga-PSMA PET/CT in BCR, even at low PSA levels. However, it may miss a few subcentimeter LNs due to lower resolution. ^99mTc-PSMA SPECT/CT could be a simple, cost-effective, and readily available imaging alternative to PET/CT.

A 25-year-old woman with a known case of papillary thyroid carcinoma conventional type referred to our center for treatment with radioactive iodine after total thyroidectomy. She received 200 mCi of radioiodine, and in the whole-body scan 1 week after the radioiodine therapy, an area of increased absorption was seen on the right side of the pelvis, which was diagnosed as an endometriotic ovarian cyst in the follow-up examinations.

A diverticulum is an outpouching of a hollow (or fluid-filled) structure in the body. They are most commonly seen in the urinary bladder, intestine, and pharyngeal region and are rarely seen in renal calyces. They are usually benign, asymptomatic, and are coincidentally detected. Due to their nonspecific clinical and radiological picture, sometimes they mimic malignant tumors, leading to misdiagnosis and treatment. We are presenting a case of 60-year-old female with right breast carcinoma, on whole body 18-fluorodeoxyglucose positron emission tomography-computed tomography; we observed an interesting finding in the right renal region mimicking renal metastasis.

Extracranial metastasis from high-grade glial tumors is an extremely rare condition with its reported incidence being <1%. The most common sites reported in the literature are leptomeninges and spinal cord, followed by the liver, lung, and skeletal system. Its low incidence is thought to be related to the intrinsic aggressive biology of the tumor, thus reducing median overall survival in patients. As there is lack of knowledge about the mechanism of extracranial spread of glioma cells, its diagnosis and management remain a major challenge. We report two cases of extracranial metastases from glial tumors to cervical nodes and postoperative site involving preauricular region detected on F18 Fluoro ethyl tyrosine (FET) positron emission tomography-computed tomography and later on confirmed with histopathology Fluoro ethyl tyrosine.

[This corrects the article on p. 83 in vol. 39, PMID: 38989319.].