Partha Sinha

The role of positron emission tomography with fluorine-18-deoxyglucose in identifying colorectal cancer metastases to liver.

Liver metastasis is a common consequence of colorectal carcinoma. Early and accurate detection of liver metastasis is crucial for a decision about partial hepatectomy, which is considered a standard and potentially curative therapy in such a setting. The presence of extrahepatic metastases will exclude surgical resection as a therapeutic option. Positron emission tomography with fluorine-18-deoxyglucose (FDG-PET) has been successful in detecting and staging a variety of malignancies. The purpose of this study was to assess the utility of FDG-PET in the accurate detection of liver and distal metastases from colorectal cancer. The results of 80 PET and computed tomography (CT) scans were compared with surgical pathology and clinical outcome. FDG-PET detected liver metastases in 28 patients, with a sensitivity of 100%. CT detected metastasis in 20 patients, giving a sensitivity of 71.4%. In addition, in one patient with negative CT findings, PET detected a focus of hypermetabolism in the region adjacent to liver, which was proven to be a second focus of primary colon carcinoma. In six patients with liver metastases, PET correctly detected extrahepatic lesions, while CT only detected hepatic lesions. In conclusion, FDG-PET is an excellent imaging modality for the detection and staging of liver metastases in patients with colorectal carcinomas.

Stereotactic Body Radiation Therapy Can Be Used Safely to Boost Residual Disease in Locally Advanced Non-Small Cell Lung Cancer: A Prospective Study

PURPOSE To report the results of a prospective, single-institution study evaluating the feasibility of conventional chemoradiation (CRT) followed by stereotactic body radiation therapy (SBRT) as a means of dose escalation for patients with stage II-III non-small cell lung cancer (NSCLC) with residual disease. METHODS AND MATERIALS Patients without metastatic disease and with radiologic evidence of limited residual disease (≤5 cm) within the site of the primary tumor and good or complete nodal responses after standard CRT to a target dose of 60 Gy were considered eligible. The SBRT boost was done to achieve a total combined dose biological equivalent dose >100 Gy to the residual primary tumor, consisting of 10 Gy × 2 fractions (20 Gy total) for peripheral tumors, and 6.5 Gy × 3 fractions (19.5 Gy total) for medial tumors using the Radiation Therapy Oncology Group protocol 0813 definitions. The primary endpoint was the development of grade ≥3 radiation pneumonitis (RP). RESULTS After a median follow-up of 13 months, 4 patients developed acute grade 3 RP, and 1 (2.9%) developed late and persistent grade 3 RP. No patients developed grade 4 or 5 RP. Mean lung dose, V2.5, V5, V10, and V20 values were calculated for the SBRT boost, and none were found to significantly predict for RP. Only advancing age (P=.0147), previous smoking status (P=.0505), and high CRT mean lung dose (P=.0295) were significantly associated with RP development. At the time of analysis, the actuarial local control rate at the primary tumor site was 82.9%, with only 6 patients demonstrating recurrence. CONCLUSIONS Linear accelerator-based SBRT for dose escalation of limited residual NSCLC after definitive CRT was feasible and did not increase the risk for toxicity above that for standard radiation therapy.

Perineural spread of skin carcinoma to the base of the skull: detection with FDG PET and CT fusion.

Abstract:A 66-year-old man underwent 2-F-18 fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) for evaluation of new-onset left jaw pain approximately 5 years after the diagnosis of squamous cell carcinoma of the lower lip. His initial surgery included a Mohs excision. As a result of

Scintigraphic confirmation of brain death.

The concept of brain death has gained importance in the past few decades to prevent futile attempts to sustain ventilation and blood circulation when the brain has lost all function and to procure beneficial tissues or life-saving organs for transplantation. However, differences remain among professional societies and various study group recommendations, as well as among individual legal statutes, in how brain death is defined and the methodology for which the diagnosis is attained. Furthermore, reports have appeared both in the medical literature and the lay press concerning quality assurance measures in brain death documentation. Scintigraphy is a commonly used technique in the evaluation of brain death and can be performed with the use of either nonspecific tracers, such as Tc99m diethylene triamine pentaacetic acid, or brain-specific tracers, such as Tc99m hexamethylpropyleneamineoxime (HMPAO). Planar imaging, with or without radionuclide angiography, continues to be the mainstay for the scintigraphic confirmation of brain death. Flow with multiprojection static planar imaging with the use of Tc99m HMPAO can be used to evaluate the cerebral hemispheres, basal ganglia, thalamus, and cerebellum. Single-photon emission computed tomography (SPECT) can provide cross-sectional information but can be difficult to perform in the context of brain death. The current use of SPECT primarily is supplemental to help differentiate overlying scalp from intracerebral activity. The reliability of SPECT to exclude flow and metabolism in the brainstem remains to be scientifically validated.

Similar pelvic abnormalities on FDG positron emission tomography of different origins.

Fluorodeoxyglucose positron emission tomography (FDG PET) has been used extensively to detect and stage various cancers. However, normal variation and inflammatory lesions may lead to false-positive interpretations of PET findings. The authors report three cases of increased pelvic FDG uptake with differing origins. Although the findings are similar, a postpartum uterus, lymphoma, and a bleeding uterus caused pelvic FDG uptake in these patients. Interestingly, of these three patients, the patient with lymphoma had the lowest level of FDG uptake. Clinical correlation is needed for the accurate interpretation of FDG-PET findings.

FDG PET/CT findings of a glomangiopericytoma.

Glomangiopericytoma (GPC) is a rare vascular neoplasm that arises almost exclusively from the nasal cavity or paranasal sinuses. GPC is also called sinonasal-type hemangiopericytoma, although current nomenclature, as well as classification in a group with myopericytomas, better emphasizes the relatively indolent behavior of this tumor. The authors present the FDG PET/CT findings of GPC in a 53-year-old with symptoms of nasal congestion and facial pressure. CT and MRI showed a nasal mass to extend along the sphenoid ridge from the posterior nasal cavity into the posterior nasopharynx. PET showed the mass to have uniformly low-grade FDG hypermetabolism. Pathologic examination of the surgical specimen showed classic features of GPC.

FDG PET of alveolar soft part sarcoma.

Alveolar soft part sarcoma (ASPS) is a very rare, but distinctive type of soft tissue sarcoma, whose name is derived from the pseudoalveolar appearance of its histology. In this report, the FDG PET/CT findings of ASPS are described in a 17-year-old asthmatic female who presented with worsening respiratory symptoms and a pelvic mass. The staging PET showed heterogeneous intense incorporation of FDG within the mass and variable FDG incorporation within the multiple lung nodules. In concordance with other soft tissue sarcomas, PET/CT helped to confirm the anatomic origin of the ASPS, to direct its biopsy, and to assess the distribution of disease.

Incidental detection of a falx meningioma on post-therapy radioiodide whole-body imaging.

An angiomatous meningioma was discovered incidentally on post-therapy whole-body imaging after 1-131 administration for papillary carcinoma of the thyroid. The patient had no neurologic signs or symptoms. He was treated for an increasing serum thyroglobulin level, and findings of previous pretherapy 1-131 and TI-201 whole-body images were negative. The mechanism for radioiodide localization within the meningioma is uncertain, although the vascularity of the tumor might be a significant factor. Primary neoplasia should be considered when intracranial localization of I-131 occurs with low to moderate intensity.

Detection of late chest wall recurrence of breast carcinoma during Tc-99m sestamibi parathyroid scintigraphy.

A 59-year-old woman underwent dual-phase parathyroid scintigraphy with Tc-99m hexakis 2-methoxy-isobutyl isonitrile (sestamibi) to aid surgical planning for primary hyperparathyroidism. Scintigraphy revealed an incidental recurrence of breast carcinoma within the anterior chest wall 8 years after mastectomy. This case illustrates how parathyroid scintigrams require careful scrutiny for second neoplasia, and why any unusual or unexpected localization should be pursued for diagnosis.

Detection of prostatic glandular adenocarcinoma during staging of non-small-cell lung carcinoma with F-18 FDG PET.

Abstract: The value of F-18 FDG PET for the staging of non–small-cell carcinoma is well established. PET reveals sites of metastatic disease undetected by conventional imaging, and it has the potential for disclosing unrelated pathology. Reported is the case of a 59-year old, with right chest wall pain and a nonproductive cough. A staging whole torso PET revealed an intensely hypermetabolic cavitary right lung mass and a site of intense FDG localization within the floor of the pelvis near the midline of the prostatic base. Subsequent right pneumonectomy and prostatic needle core biopsies yielded histologically different carcinomas of the lung (poorly differentiated non–small-cell) and prostate (extensive adenocarcinoma). The difficulty in differentiating urinary tract pathology from normal urinary activity of FDG is illustrated.