Piyush Chandra

Functional imaging in primary tumour-induced osteomalacia: relative performance of FDG PET/CT vs somatostatin receptor-based functional scans: a series of nine patients.

Localization of phosphatonin‐producing mesenchymal tumours in patients with primary tumour‐induced osteomalacia (pTIO) is challenging. Functional imaging plays an important role in the localization of these tumours.

Somatostatin receptor spect/ct using 99mTc labeled hynic-toc aids in diagnosis of primary optic nerve sheath meningioma

Primary optic nerve sheath meningiomas (ONSM) are rare, benign and slow growing tumor involving the intra-orbital/intra-canalicular segment of the optic nerve. Untreated, they can potentially lead to visual deterioration. Magnetic resonance (MR) is the gold standard imaging modality for diagnosing the entity. Often, a clinical dilemma exists to narrow the differential diagnosis of an enhancing intra-orbital mass on MR. Molecular imaging provides a high degree of precision in diagnosing meningioma in view of relatively high levels of somatostatin receptor expression by these tumors. The following case demonstrates the potential clinical utility of somatostatin receptor SPECT using 99mTc- labeled HYNIC-TOC in clinical diagnosis of ONSM.

Clinical Utility of 18 F-FDG PET/CT in brachial plexopathy secondary to metastatic breast cancer

Role of fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in breast cancer is rapidly evolving. Brachial plexopathy is a rare clinical entity in follow-up of operated breast cancer patients, who presents with disease recurrence in the axilla. Conventionally, magnetic resonance imaging is the imaging modality of choice for diagnostic evaluation in these cases and only few case reports/short studies have explored the utility of PET/CT in this clinical indication. We present here a short case series to demonstrate the utility of PET/CT as an important adjunctive imaging modality to magnetic resonance to supplement diagnosis of brachial plexopathy, differentiate radiation-induced brachial plexopathy from neoplastic plexopathy, accurately restage the disease and to monitor response to chemotherapy.

Common patterns of perineural spread in head-neck squamous cell carcinoma identified on fluoro-deoxy-glucose positron emission tomography/computed tomography

Perineural spread in HNSCC is associated with dismal prognosis and decreased overall survival. Clinical diagnosis of this relatively asymptomatic entity is usually delayed and made incidentally on imaging. MRI is gold standard imaging for early diagnosing of this condition owing to its excellent anatomic resolution. With the ever increasing use of PET/CT in commonly encountered cancer such as HNSCC for staging and re-staging, observing perineural spread on PET/CT is not infrequent. Through this pictorial essay we demonstrate the common patterns of perineural spread in HNSCC on PET/CT with the aim of improving reporting accuracy across readers.

Calcified peritoneal metastasis identified on 18F-fluoride positron emission tomography/computed tomography: Importance of extraosseous uptake of F-18 fluoride.

F-18 NaF positron emission tomography/computed tomography (PET/CT) is used for the evaluation of malignant and nonmalignant osseous disease. Extraosseous uptake of 18 fluoride-NaF has been observed in the arterial vasculature, gastrointestinal tract, and genitourinary tract. We describe a case of a woman with carcinoma of unknown primary in whom F-18 NaF PET/CT showed tracer uptake in the calcified peritoneal metastasis. Extraosseous findings on F-18 NaF PET/CT, though rare, may be visualized and may result in important management changes.

Comparison of SPECT/CT and planar lympho-scintigraphy in sentinel node biopsies of oral cavity squamous cell carcinomas

Introduction: Evidence supporting the use of Sentinel node biopsy (SNB) for nodal staging of early oral squamous cell carcinomas (OSCC) appears to be very promising. Pre-operative lymphatic mapping using planar lymphoscinitigraphy (PL) with or without SPECT/CT in the SNB procedure is useful in sentinel node localization and for planning appropriate surgery. Recently, a large prospective multi-centric study evaluating SNB in cutaneous melanoma, breast and pelvic malignancies, demonstrated that adding SPECT to PL leads to surgical adjustments in a considerable number of patients. Our aim of this study was to evaluate the incremental value of additional SPECT/CT over PL alone in SNB for OSCC. Materials and Methods: This was a retrospective analysis of 44 patients (40- tongue, 4- buccal mucosa) with T1-T2, clinically N0 oral cavity SCC who underwent sentinel node biopsy procedure. PL and SPECT lymphoscinitigraphy images were compared for pre-operative mapping of sentinel nodes. Results: Using a handheld gamma probe, a total of 179 sentinel nodes were harvested, with a mean of 4.06 per patient. PL revealed 75 hotspots with a mean of 1.70 per patient, and SPECT/CT revealed 92 hotspots with a mean of 2.09 per patient. Additional hotpots were identified in 14 patients on SPECT/CT, which included 4 patients, where PL did not detect any sentinel nodes. Conclusion: Pre-operative SPECT/CT in addition to planar lympho-scinitigraphy in sentinel node biopsies of oral cavity SCC detects more number of sentinel nodes compared to planar imaging alone. The higher sensitivity of SPECT combined with better anatomical localization using diagnostic CT may further improve the precision of SNB procedure.

Diagnostic accuracy and impact of fluorodeoxyglucose positron emission tomography/computed tomography in preoperative staging of cutaneous malignant melanoma: Results of a prospective study in Indian population

The aim of the study was to evaluate the diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) in staging patients with primary cutaneous malignant melanoma (CMM). We further compared the performance of PET/CT with conventional imaging (CI) (CT and ultrasonography [USG]) and assessed the impact of PET/CT on disease management. This was a single institution, prospective, double-blinded study, recruiting a total of 70 treatment naïve patients. The sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of PET/CT for N staging were 86%, 96%, 80%, and 97%, respectively. The sensitivity, specificity, NPV, and PPV of PET/CT for M staging were 87%, 100%, 93%, and 100%, respectively. The diagnostic accuracy of the PET/CT was superior to CI for N staging (90% vs. 84% for CT and 80% for USG) and M staging (95% vs. 90% for CT). No statistically significant difference was noted between PET/CT and CI for N staging (PET/CT vs. CT, P = 0.125; PET/CT vs. USG, P- 0.063) or M staging (PET/CT vs. CT, P = 0.125). PET/CT upstaged 23% of patients with clinically localized disease and 58% of patients with clinically palpable regional nodes. To conclude, fluorodeoxyglucose PET/CT is a highly sensitive and specific imaging modality for preoperative staging of primary CMMs. PET/CT impacts disease management in significant number of patients and should be especially recommended in all patients with clinically palpable regional nodes.

Initial clinical experience with 68Ga-DOTA-NOC prepared using 68Ga from nanoceria-polyacrylonitrile composite sorbent-based 68Ge/68Ga generator and freeze-dried DOTA-NOC kits

Somatostatin receptor positron emission tomography–computed tomography (PET/CT) with 68Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) peptides have become an indispensable part of disease assessment in patients with neuroendocrine tumors and forms the basis of personalized therapy with peptide receptor-based radionuclide therapy. With growing utilization of PET/CT in developing countries, availability of the indigenous GMP-certified 68Ge/68Ga generators is expected to further promote cost-effective molecular imaging service to the cancer patients. We present our initial clinical experience in 32 patients injected with 68Ga-DOTA-NOC prepared using 68Ga eluted from Bhabha Atomic Research Centre nanoceria-polyacrylonitrile sorbent-based 68Ge/68Ga generator and freeze-dried DOTA-NOC cold kits.

“Drop” metastases from an operated case of intracranial anaplastic ependymoma identified on fluoro-2-deoxyglucose positron emission tomography/computed tomography

The seeding of tumor through cerebrospinal fluid (CSF) from primary intracranial tumors is very rare, often goes undetected, and is usually identified only on autopsy. CSF cytology along with magnetic resonance imaging constitutes the standard approach of diagnosing this grave condition. Use of fluoro-2-deoxyglucose positron emission tomography/computed tomography (PET/CT) in indentifying spinal metastases from primary intracranial malignancies is very limited and has been reported in patients with metastatic glioblastoma multiforme and medulloblastomas. We present a rare case of metastatic anaplastic ependymoma to show the potentially clinically utility of PET/CT in diagnosing leptomeningeal or the so-called “drop” metastases.

Perineural spread of mucoepidermoid carcinoma of parotid gland involving V, VI, and VII cranial nerves demonstrated on positron emission tomography/computed tomography

Perineural spread (PNS) in head and neck malignancies has been associated with extremely poor prognosis. Through this interesting case, we demonstrate the PNS of a mucoepidermoid carcinoma of parotid gland with simultaneous involvement of V, VI, and VII cranial nerves identified on positron emission tomography/computed tomography.