FDG PET/CT Aiding in Early Diagnosis of Central Pontine Myelinolysis.

ABSTRACT: We report a 70-year-old man with central pontine myelinolysis who presented in the emergency department with recent onset altered sensorium and tremors (Glasgow Coma Scale score, 13). Laboratory findings revealed hyponatremia and hypokalemia. MRI brain was unremarkable. Subsequently, patient was referred for FDG PET/CT to rule out malignancy or paraneoplastic syndrome. FDG PET revealed focal radiotracer uptake in the pons without any underlying CT abnormality consistent with central pontine myelinolysis, thus aiding in early diagnosis where conventional imaging modality was unremarkable.

Solitary Penile Metastasis from Prostate Cancer on 18F-Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography.

We report a case of a 66-year-old man with prostate cancer who underwent 18F-prostate-specific membrane antigen positron emission tomography/computed tomography for baseline staging that revealed primary lesion in prostate gland along with a solitary metastatic deposit in the penile shaft. Penile metastasis is rare and usually associated with widespread metastatic disease. Solitary penile metastasis is even rarer and can present as a unifocal, multifocal, or diffuse lesion. Early detection is important in guiding treatment and preventing complications.

Contrast Media in PET/Computed Tomography Imaging.

Is there a need for the contrast-enhanced PET/computed tomography (CT) scan or is the low-dose, non-contrast-enhanced PET/CT scan sufficient? The topic has been debated time and again. Although low-dose noncontrast CT serves the purpose of simple anatomic correlation and attenuation correction of PET images, many times patients have to undergo additional contrast-enhanced diagnostic imaging modalities, which may lead to a delay in decision-making. In this review, the authors have addressed various such issues related to the use of contrast agents and special techniques of clinical interest based on their utility in dual-modality PET/CT.

18F-FDG PET/CT of Widespread Rosai-Dorfman Disease.

We present a rare case of Rosai-Dorfman disease who was sent for whole-body 18F-FDG PET/CT to know the exact extent of involvement. PET/CT revealed extensive nodal and extranodal involvement from head to toe including osteolytic lesions in metacarpals, metatarsals, and phalanges. It is important to know the exact extent of the disease as this may alter the patient management.

Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with (99m)Tc-methylene diphosphonate single photon emission computed tomography/computed tomography.

We present the case of a 35-year-old man with calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia variant scleroderma who presented with dysphagia, Raynaud's phenomenon and calf pain. (99m)Tc-methylene diphosphonate bone scintigraphy was performed to identify the extent of the calcification. It revealed extensive dystrophic calcification in the left thigh and bilateral legs which was involving the muscles and was well-delineated on single photon emission computed tomography/computed tomography. Calcinosis in scleroderma usually involves the skin but can be found in deeper periarticular tissues. Myopathy is associated with a poor prognosis.

Metastatic superscan on (99m)Tc-methylene diphosphonate bone scintigraphy in pediatric neuroblastoma.

Excessive skeletal radioisotope uptake in relation to soft tissues along with absent or faint activity in the genitourinary tract on bone scintigraphy (BS) is known as a "superscan." However the association of pediatric solid tumor malignancy with metastatic superscan has not been reported previously. We here describe two such cases of neuroblastoma who presented with metastatic superscan on (99m)Tc-methylene diphosphonate BS. Presence of a superscan usually indicates an advanced stage of the disease. The patient prognosis is usually poor. Though extremely rare superscan can be associated with pediatric solid tumor malignancies and should be kept in mind while reporting such cases.

Accurate Characterization of Skeletal Lesions in Tuberous Sclerosis Complex Using 99mTc MDP SPECT/CT.

We report a 15-year-old patient with tuberous sclerosis complex or Bourneville's disease with history of generalized tonic-clonic seizure for last 2 years and was currently on antiepileptic medication. He also had a history of left nephrectomy for renal cell carcinoma clear cell type. The patient had multiple adenoma sebaceum over the nasolabial region, ash leaf spots over the lower limbs, a Shagreen patch over the back, and multiple calcified tubers in the subependymal region. He was then referred for the skeletal scintigraphy to look for skeletal lesions, which revealed involvement of bilateral humeri, tibiae, and iliac bones accurately characterized on SPECT/CT.

18F-FDG PET-CT for Evaluation of Cardiac Angiosarcoma: A Case Report and Review of Literature.

Cardiac angiosarcomas are rare neoplasms. We here present the case of a 24 year old male with a cardiac mass which was characterised as malignant on 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT). In addition 18F-FDG PET-CT also demonstrated pericardial infiltration and bone metastases. The tumor was confirmed to be angiosarcoma on biopsy and palliative chemotherapy was started. Here we have highlighted the potential role of 18F-FDG PET-CT in patients with cardiac angiosarcoma and presented a brief review.

Synchronous thoracic and abdominal enteric duplication cysts: Accurate detection with (99m)Tc-pertechnetate scintigraphy.

Enteric duplication cysts (EDCs) are uncommon congenital anomalies, which can occur anywhere along the gastrointestinal tract and vary greatly in presentation, size, location and symptoms. Ectopic gastric mucosa is reported to be found in 20-30% of these duplications. (99m)Tc-pertechnetate scintigraphy is a useful modality for preoperative localization of the ectopic functioning gastric mucosa in the EDCs. We report a case where (99m)Tc-pertechnetate scintigraphy was useful in detecting synchronous thoracic and abdominal duplication cysts with functioning gastric mucosa thus having an impact on the patient management.

An uncommon case showing three different pathologies on (99m)technetium-methylene diphosphonate bone scintigraphy.

(99m)Technetium-methylene diphosphonate bone scintigraphy (BS) has an important role in evaluating skeletal pathology, especially its extent. Incidental extra-osseous uptake may sometimes be seen in soft-tissue pathologies. We present a 64-year-old female with skull base osteomyelitis referred for BS which revealed involvement of the skull base on the left side, uptake was also noted in bilateral lungs secondary to hypercalcemia of renal failure and in the D12-L1 vertebrae as the patient had a history of Pott's spine. This is perhaps a unique case showing three findings each of a different etiology in the same scan.

Evaluation of (68)Ga-DOTANOC PET/CT imaging in a large exclusive population of pancreatic neuroendocrine tumors.

PURPOSE: To evaluate the diagnostic accuracy of (68)Ga-DOTANOC PET/CT imaging in a large exclusive population of pancreatic neuroendocrine tumors (NETs). METHODS: Data of 141 (mean age 46.2 ± 15.2 years) patients who underwent 178 (68)Ga-DOTANOC PET/CT studies for diagnosis/staging (n = 88) and restaging (n = 90) of pancreatic NET were retrospectively analyzed. PET/CT results were compared to conventional imaging (CIM) when available (n = 86). Histopathology and/or clinical/imaging follow-up (minimum 6 months) were used as reference standard. RESULTS: The overall sensitivity, specificity, and accuracy of (68)Ga-DOTANOC PET/CT were 85.7%, 79.1%, and 84.8%. The corresponding values were 73%, 50%, and 70.4% for diagnosis/staging groups and 98.6%, 100%, and 98.8% for restaging groups. The accuracy was significantly higher for restaging as compared to diagnosis/staging (P < 0.0001) and in non-insulinoma tumors than insulinomas (P < 0.0001). The SUVmax of primary tumors was significantly higher than metastatic lesions overall (P = 0.001), as well as in diagnosis/staging (P = 0.041) and restaging (P = 0.0003) subgroups. When available, CIM was less specific than (68)Ga-DOTANOC PET/CT (P < 0.001) and showed fewer lesions. CONCLUSIONS: (68)Ga-DOTANOC PET/CT is useful for diagnosis/staging and restaging of patients with pancreatic NET. It demonstrates more lesions compared to CIM and is more specific.

Carcinoma of unknown primary of neuroendocrine origin: Accurate detection of primary with (68)Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-Octreotide positron emission tomography/computed tomography enterography.

(68)Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-Octreotide ((68)Ga-DOTANOC) positron emission tomography/computed tomography (PET/CT) is an excellent modality in patients with carcinoma of unknown primary of neuroendocrine origin. Most of the primary lesions are located in mid gut region where the lesions have poor resolution due to undistended and overlapping intestinal loops and motility-related artifacts. Although PET/CT enteroclysis, enterography and colonography have been described with (18)F-fluorodeoxyglucose, PET/CT enterography with(68)Ga-DOTANOC has not been described in the literature. Here, we present a case where(68)Ga-DOTANOC PET/CT enterography was useful in identifying the primary neuroendocrine tumor lesion in small intestine with accurate delineation.

Asymmetrically increased rib cage uptake on bone scintigraphy: Incidental detection of pleural mesothelioma on single photon emission computed tomography/computed tomography.

Follow-up bone scintigraphy (BS) in a patient of carcinoma left breast, who was treated with surgery followed by radiotherapy 12 years back, revealed asymmetrically increased radiotracer uptake in left-sided ribs. Since, this pattern was atypical for metastatic rib involvement, single photon emission computed tomography/computed tomography (SPECT/CT) of thorax was done in the same setting which revealed circumferential nodular left-sided pleural thickening. Biopsy confirmed it to be pleural mesothelioma. Left-sided ribs showed no abnormality on CT, thus suggesting the rib uptake as reactive in nature. This pattern of asymmetric rib uptake on BS should be kept in mind and warrants further investigation for determining underlying pathology.

Ciliary body metastasis in a patient with non-small cell lung carcinoma--incidental detection with 18F-FDG PET/CT.

Ciliary body metastasis in a case of lung cancer is very rare. Intraocular metastasis by any cancer most commonly involves choroid followed by iris and ciliary body. We present a case of a 71-year-old male with non-small cell lung cancer who was found to have an 18F-FDG avid right lung mass. Incidentally a focus of abnormal increased 18F-FDG uptake was noted in the region of ciliary body in the right eyeball. The findings were confirmed to be a metastatic lesion in ciliary body on Ultrasonography and MRI. Our case depicts this extremely rare occurrence corroborated by various modalities.

Lymphoma and tuberculosis: temporal evolution of dual pathology on sequential 18F-FDG PET/CT.

Tuberculosis can often be seen in patients undergoing chemotherapy for lymphoma, especially in endemic countries. As both tuberculosis and lymphoma can lead to hypermetabolic lesions of F-FDG PET/CT, a diagnostic dilemma often ensues. We present the sequential F-FDG PET/CT images of a 22-year-old female patient with Hodgkin lymphoma who developed tuberculosis and later relapse of lymphoma. These images present the temporal evaluation of the dual pathology on F-FDG PET/CT.

Diuretic 68Ga DOTANOC PET/CT in imaging of bladder paraganglioma.

Urinary bladder paragangliomas are exceedingly rare tumors. A 22-year-old woman with bladder paraganglioma underwent Ga DOTANOC PET/CT for proper localization of the primary tumor and to rule out locoregional and distant metastases. Ga DOTANOC-avid bladder mass was detected with no other abnormal site of radiotracer uptake elsewhere. Although radioactive urine can mask urinary paragangliomas, diuretic method can aid tumor detection by Ga DOTANOC PET/CT.

Von Hippel-Lindau syndrome: demonstration of entire disease spectrum with (68)Ga-DOTANOC PET-CT.

Von Hippel-Lindau (VHL) syndrome is a rare neoplastic disorder characterized by central nervous system (CNS) and visceral tumors. We here present (68)Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-Nal3-Octreotide positron emission tomography computed tomography findings in a 52 year old female with VHL syndrome, demonstrating both CNS and visceral tumors.