Gary Marano

Simultaneous MRI and PET imaging of a rat brain.

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging.

Epidural Lipomatosis Simulating an Epidural Abscess: Case Report and Literature Review

A case of epidural lipomatosis in a 49-year-old man presenting with paraparesis, midthoracic pain, and Staphylococcus aureus pneumonia is reported. The patient had been on low dose corticosteroid therapy for 7 years for rheumatoid arthritis. The clinical and myelographic findings suggested a diagnosis of epidural abscess, but the only abnormality discovered at operation was abundant fatty tissue in the dorsal epidural space significantly compressing the spinal cord, and this was partially removed. Postoperative neurological improvement suggested that the lipomatosis was responsible for the spinal cord compression and dysfunction. If this diagnosis had been suspected, it might have been confirmed by magnetic resonance imaging or postmyelography computed tomographic scanning. With such a diagnosis, an alternative treatment could have been to decrease the steroid dose, observe for clinical improvement, and perhaps avoid operation.

MRI of peroneal nerve entrapment due to a ganglion cyst

Ganglion cysts are relatively common entities, but impingement upon the peripheral nerves is rare. We describe a case in which peroneal nerve palsy was caused by a ganglion cyst demonstrated by MRI.

Initial clinical test of a breast-PET scanner

Introduction: The goal of this initial clinical study was to test a new positron emission/tomography imager and biopsy system (PEM/PET) in a small group of selected subjects to assess its clinical imaging capabilities. Specifically, the main task of this study is to determine whether the new system can successfully be used to produce images of known breast cancer and compare them to those acquired by standard techniques.

Fluorodeoxyglucose-positron emission tomographic imaging for the diagnosis of mesial temporal lobe epilepsy.

OBJECTIVE Fluorodeoxyglucose (FDG)-positron emission tomographic (PET) imaging plays an important role in the evaluation of intractable epilepsy. The metabolic defect has proven utility in the lateralization of temporal lobe epilepsy. However, the role of FDG–PET imaging in the localization of a seizure focus within the temporal lobe is uncertain. We evaluated FDG–PET imaging for the capability to localize a temporal seizure focus within the mesial structures. METHODS Twenty-eight patients who underwent selective amygdalohippocampectomy for intractable temporal lobe epilepsy were studied. Patients were divided into 2 groups: those who were free of seizures (FS) and those with persisting seizures postoperatively. FS patients were defined by having mesial temporal lobe epilepsy (MTLE). Preoperative FDG–PET activity was evaluated in temporal lobe structures and contrasted with magnetic resonance imaging (MRI) for usefulness in identifying MTLE in an individual. RESULTS Pathology of the hippocampus revealed mesial temporal sclerosis in all but 1 patient. Qualitative visual inspection of the MRI scan was not reliable in the identification of MTLE (P = 0.15). MRI volumetry found smaller mesial temporal structures (P = 0.04) in FS patients. Mesial temporal metabolic activity was reduced in the FS group (hippocampus, P = 0.001). However, a combination of imaging modalities was found to be the best predictor of MTLE. PET imaging plus MRI qualitative inspection identified all patients with and without MTLE correctly and was superior to MRI alone (P = 0.01 and P = 0.02, respectively). CONCLUSION MRI volumetry and PET imaging were comparable (P = 0.73) and able to identify MTLE in most patients, but a combination of PET imaging and MRI visual inspection was superior in the recognition of MTLE.

Correlation Among [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography, Cancer Antigen 27.29, and Circulating Tumor Cell Testing in Metastatic Breast Cancer

BACKGROUND Tumor marker cancer antigen (CA) 27.29 and combined [18F]-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) scans are used to follow up response to treatment and disease progression in patients with metastatic breast cancer (MBC). Recently, circulating tumor cell testing (CTC) has been used in this context. It is not known if 1 of the 3 tests can be a surrogate for another. PATIENTS AND METHODS We analyzed a database of 35 patients with MBC. There were 173 time points (> or = 6 weeks apart) when > or = 2 of these tests were performed. Correlation among all the 3 tests was statistically analyzed. RESULTS Results of PET/CT scans were compared with CA 27.29 at 163 time points. There was a statistically significant correlation between both groups (P = .02); however, sensitivity of CA 27.29 to detect metastatic disease observed on PET/CT scan was 59%. The results of PET/CT scans were compared with CTC at 93 events, where there was a statistically significant correlation between both groups (P = .0002); however, sensitivity of CTC to detect metastatic disease shown on PET/CT scans was 55%. Cancer antigen 27.29 results were also compared to CTC at 100 events, where there was a statistically significant correlation between both groups (P = .0002). However, only 64% of patients with high CA 27.29 had abnormal CTC. CONCLUSION Our data shows correlation among PET/CT scan, CA 27.29, and CTC. However, both CA 27.29 and CTC had poor sensitivity and negative predictive value to detect metastatic disease observed on PET/CT scan. Normal CA 27.29 testing or CTC has to be interpreted cautiously in patients with MBC.

Concept of an upright wearable positron emission tomography imager in humans

Positron Emission Tomography (PET) is traditionally used to image patients in restrictive positions, with few devices allowing for upright, brain‐dedicated imaging. Our team has explored the concept of wearable PET imagers which could provide functional brain imaging of freely moving subjects. To test feasibility and determine future considerations for development, we built a rudimentary proof‐of‐concept prototype (Helmet_PET) and conducted tests in phantoms and four human volunteers.

Detection of Axillary Lymph Node Metastases and Extra-Axillary Metastases With FDG PET/CT in Breast Cancer Patients Scheduled for Neoadjuvant Chemotherapy

develop procedures that could be used in the treatment of peripheral vascular disease. In each case, we aim to provide quantitative measurements which will aid physicians in the characterization of disease status and the effects of therapeutic measures, so that treatments can be applied with optimal effectiveness by taking into account the oxygen-dependent aspects of the therapy. The overall goal is to enhance clinical outcomes. Results: Tumor oximetry measurements have been performed in tumor tissues of 12 patients during courses of radiation and chemotherapy. Tumor types include melanoma, basal cell, soft tissue sarcoma, and lymphoma, andmeasurement sites have ranged from the feet to the scalp. Very recent results and analyses indicate that using a simple clinically applicable approach with breathing carbogen, tumors can be characterized in regard to whether or not they respond to this hyperoxic treatment which does raise the pO2 in the vascular system. Some tumors did not respond at all and some had only minimal changes while others had robust changes in tumor pO2. Conclusions: These results indicate that it should be feasible to more adequately determine the effectiveness of hyperoxic treatments and, therefore, both individualize therapy and develop more robust strategies for optimizing hyperoxic therapies.

Positron emission tomography in Warthin’s tumor mimicking malignancy impacts the evaluation of head and neck patients

PURPOSE 1) To determine SUVs and PET/CT characteristics of Warthins tumors in patients presenting to a head and neck cancer clinic. 2) To analyze the impact of PET/CT on the clinical course of these patients. MATERIALS AND METHODS This is a single-institution retrospective analysis of patients with proven Warthins tumors who underwent PET/CT done at or near the time of diagnosis and presented to a head and neck cancer practice. Data were obtained from the electronic medical records of these patients and the imaging and pathology databases. RESULTS Six patients with Warthins tumor met the criteria for and form the study cohort. Three patients had bilateral tumors. The SUVs for Warthins varied from 3.4 to 16.1 in these patients, with an average of 7.8 and these SUVs were higher for Warthins than for the cancers. These findings on PET/CT in this group required additional workup of all patients and required FNA, surgery or SPECT-CT to confirm the diagnosis. CONCLUSION Although it is known that Warthins tumor may be hypermetabolic on PET, this finding in the parotid or neck on PET/CT alters the evaluation and treatment of head and neck cancer patients and patients with cancers outside the head and neck by raising the concern about metastatic disease or multiple primary cancers. In other patients, PET/CT obtained for other reasons may prompt concern about incidental malignancy. This series specifically characterizes clinical features, SPECT-CT and FNA findings that can help reinforce the diagnosis of Warthins and facilitate management.

Radiation exposure in patients (pts) with newly diagnosed breast cancer (BC) within first year (yr) from diagnostic procedures (DP).

123 Background: Radiation exposure is associated with an increased risk of secondary cancers. Few studies have examined radiation exposure from DP in BC. METHODS We retrospectively analyzed the cumulative radiation doses (millisievert [mSv]) of routine DP done in 305 pts during the 1st yr following BC diagnosis between Jan 2008-Oct 2010. Data regarding the frequency of DP including mammograms, sentinel lymph node biopsies, X-rays, computed tomographic (CT) and/or positron emission tomographic (PET) scans, MUGA scans and bone scans were collected. Mean radiation doses of DP were obtained from Departments of Nuclear Medicine and Radiation at our institution. Kruskal-Wallis test and post-hoc pairwise comparisons were used to assess the influence of various factors including age, histology, ER/PR (Estrogen/Progesterone) status and stage on the amount of radiation exposure. RESULTS Mean radiation exposure relative to various factors is shown in the Table. Pts < 40yrs had a significantly higher radiation dose as compared to pts > 60yrs (35.9mSv vs. 19.2mSv; p = 0.009). Pts with DCIS (ductal carcinoma in situ) had a significantly less radiation exposure as compared to IDC (infiltrating ductal carcinoma) and ILC (invasive lobular carcinoma) (8.5mSv vs. 26.7mSv and 22.4mSv respectively; p< 0.0001). Stage ≥ IIB disease was associated with a significantly higher radiation exposure (p< 0.0001). Stage ≥ IIIA was the only factor associated with a higher radiation dose from PET/CTs (p< 0.0001). CONCLUSIONS Radiation exposure from DP is significant in the 1st yr of BC diagnosis, especially for younger and advanced stage pts. Risk is small but relevant, especially in younger pts. [Table: see text].