James W. Fletcher

Surveillance for recurrent head and neck cancer using positron emission tomography.

PURPOSE Earlier detection of head and neck cancer recurrence may improve survival. We evaluated the ability of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) to detect recurrence in a prospective trial using sequential PET scans. PATIENTS AND METHODS Serial posttherapy FDG-PET was prospectively performed in 44 patients with stage III or IV head and neck cancer. PET was performed twice during the first posttreatment year (at 2 and 10 months after therapy) and thereafter as needed. After therapy, patients were grouped, based on tissue biopsies, into those who achieved a complete response (CR) and those who had residual disease (RD). Patients who achieved a CR were further grouped into those without evidence of disease and those who had recurrence by 1 year after completion of therapy. Disease status as determined by physical examination (PE), PET, and correlative imaging was compared. RESULTS Eight patients were lost to follow-up and six had RD after therapy. Of the remaining 30 patients with a CR, 16 had recurrence in the first year after therapy. Five of these 16 patients had recurrence detected by PET only, four by PET and correlative imaging only, five by PE and PET only, and two by PE, correlative imaging, and PET. Only PET detected all recurrences in the first year. PET performed better than correlative imaging (P =.013) or PE (P =.002) in the detection of recurrence. CONCLUSION PET can detect head and neck tumor recurrence when it may be undetectable by other clinical methods. FDG-PET permits highly accurate detection of head and neck cancer recurrence in the posttherapy period.

Evaluation of chemotherapy response in patients with advanced head and neck cancer using [F-18]fluorodeoxyglucose positron emission tomography

[F‐18]Fluorodeoxyglucose (FDG)‐positron emission tomography (PET) can measure the metabolic activity of tissues; FDG‐PET may be able to predict response to chemotherapy by identifying changes in tumor metabolism. Measurement of response to treatment may help improve survival in the management of advanced head and neck cancer. We evaluated this particular use of FDG‐PET in patients participating in a neoadjuvant organ‐preservation protocol using taxol and carboplatin and compared pathologic response after chemotherapy with changes in tumor metabolism measured by FDG‐PET.

A Comparison of the Diagnostic Accuracy of 18F-FDG PET and CT in the Characterization of Solitary Pulmonary Nodules

CT and PET are widely used to characterize solitary pulmonary nodules (SPNs). However, most CT accuracy studies have been performed with outdated technology and methods, and previous PET studies have been limited by small sample sizes and incomplete masking. Our objective was to compare CT and PET accuracy in veterans with SPN. Methods: Between January 1999 and June 2001, we recruited 532 participants with SPNs newly diagnosed on radiography and untreated. The SPNs were 7–30 mm. All patients underwent 18F-FDG PET and CT. A masked panel of 3 PET and 3 CT experts rated the studies on a 5-point scale. SPN tissue diagnosis or 2-y follow-up established the final diagnosis. Results: A definitive diagnosis was established for 344 participants. The prevalence of malignancy was 53%. The average size was 16 mm. Likelihood ratios (LRs) for PET and CT results for combined ratings of either definitely benign (33% and 9% of patients, respectively) or probably benign (27% and 12%) were 0.10 and 0.11, respectively. LRs for PET and CT results for combined ratings of indeterminate (1% and 25%), probably malignant (21% and 39%), or definitely malignant (35% and 15%) were 5.18 and 1.61, respectively. Area under the receiver operating characteristic curve was 0.93 (95% confidence interval, 0.90–0.95) for PET and 0.82 (95% confidence interval, 0.77–0.86) for CT (P < 0.0001 for the difference). PET inter- and intraobserver reliability was superior to CT. Conclusion: Definitely and probably benign results on PET and CT strongly predict benign SPN. However, such results were 3 times more common with PET. Definitely malignant results on PET were much more predictive of malignancy than were these results on CT. A malignant final diagnosis was approximately 10 times more likely than a benign final diagnosis in participants with PET results rated definitely malignant.

Magnetic resonance imaging of lesions of synovial origin

Three patients with histologically differing lesions of synovial origin and two with synovial cysts, one of which was a dissecting popliteal cyst, were examined by magnetic resonance imaging (MR) and computerized tomography (CT). The three histologically proven synovial lesions were synovial sarcoma, diffuse giant cell tumor of tendon sheath, and synovial chondromatosis. In two of the five patients MR provided better anatomic and morphologic appreciation than CT, while in the others they were of equal value. CT demonstrated calcification in two of the lesions while on MR calcification could be identified in only one patient where it outlined the mass. MR did not demonstrate calcification in the substance of the diffuse giant cell tumor of tendon sheath. Coronal, transverse, and sagittal images of magnetic resonance graphically demonstrated the extent of the soft tissue masses and their relationship to bone, vessels, and soft tissue structures. Synovial sarcoma had a shorter T1 than diffuse giant cell tumor of tendon sheath (these two lesions being of comparable size) and also had a uniformly longer T2. The dissecting popliteal cyst showed the most intense signals on the T1 weighted images, while the uncomplicated synovial cyst showed a long T1. On the T2 weighted images, each type of cyst showed a long T2. The variance and overlap of intensity of MR signals suggest limited specificity in predicting the histologic nature of the synovial lesion.

High signal intensity soft tissue masses on T1 weighted pulsing sequences

On T1 weighted pulsing sequences, the majority of soft tissue masses are of low signal intensity and show high intensity signals on T2 weighting. There however is a subset of soft tissue masses of varied histology that shows high signal intensity on T1 weighted pulsing sequences. These masses have either fat or blood in their substance. Lipomatous and hemangiomatous lesions that did not show high-signal intensity on T1 weighting were also encountered and are discussed. Present experience with MRI of soft tissue masses suggests that there is a limited spectrum of entities that produce high-signal intensity T1 weighted soft tissue masses.

Analysis of radiocontrast-induced nephropathy by dual-labeled radionuclide clearance

RATIONALE AND OBJECTIVES.This study was devised to develop a method of measuring the acute effects of radiocontrast media on renal function and assessing the relationship of the dose of radiocontrast media infused with the incidence of radiocontrast- induced renal failure. In addition, the drug adenosine phosphate-magnesium chloride (ATP-MgCl2) was evaluated as a renoprotective agent. METHODS.Eighteen patients with pre-existing renal impairment, (serum creatinine greater than 133 µmol/L) were randomized to receive a continuous infusion of ATP-MgCI2 or placebo before and during a radiocontrast procedure. Subjects were monitored with daily serum creatinine and with radionuclide renal clearance studies at baseline, during, and 24 hours after the radiocontrast procedure. RESULTS.There was an initial deterioration in renal clearance in the entire study group (from 44.2 ± 4.6 to 32.6 ± 3.9 mL/min, P = .001) which was independent of the dose of radiocontrast infused. There was a persistent deterioration in renal clearance only in those who received greater than 135 mL of contrast media (from 48.6 ± 7.8 to 37.1 ± 3.9 mL/min, P = .05). There also was an increase in serum creatinine that persisted only in those subjects who received greater than 135 mL of contrast media (230 ± 27 to 283 ± 44 ( µmol/L, P = .01). CONCLUSION.Persistent deterioration in renal function after radiocontrast administration appears to be dose-dependent and is not prevented by the use of ATP-MgCl2. Radionuclide techniques are useful in monitoring acute changes in renal function during radiocontrast procedures and may be of value in assessing renal impairment in future intervention studies.

Evaluation of 99mTc-Pyrophosphate as a Bone Imaging Agent

A preliminary evaluation of the bone-localizing properties of 99mTc-pyrophosphate demonstrates favorable skeletal concentration, rapid blood and renal clearance, and ease of chemical reproducibility. The authors report the results of bone imaging with 99mTc-pyrophosphate for the detection of osseous metastases in 30 patients with known or suspected primary carcinoma.

67Ga Citrate Distribution Following Whole-Body Irradiation or Chemotherapy

Whole-body retention, organ distribution, excretion, and serum binding of 67Ga were evaluated in rats under normal conditions and following whole-body gamma irradiation, vincristine sulfate, or mechlorethamine. The results suggest that both irradiation and chemotherapy lead to reduced whole-body retention of injected radiogallium, explained in part by an alteration in the serum binding of gallium. Recognition of these findings should be considered in interpreting decreased tumor concentration of gallium in patients following radiotherapy or chemotherapy.

American Society of Nuclear Cardiology and Society of Nuclear Medicine and Molecular Imaging Joint Position Statement on the Clinical Indications for Myocardial Perfusion PET

Expert Content Reviewers: Frank M. Bengel MD, Daniel S. Berman MD, Dennis A. Calnon MD, Paolo Camici MD, James A. Case PhD, Manuel D. Cerqueira MD, Panithaya Chareonthaitawee MD, Robert A. deKemp PhD, Dominique Delbeke MD, PhD, Marcelo F. Di Carli MD, Sharmila Dorbala MD, James W. Fletcher MD, Henry Gewirtz MD, K. Lance Gould MD, PhD, Robert Gropler MD, PhD, Justin A. Lundbye MD, Jamshid Maddahi MD, Terrence Ruddy MD, Heinz R. Schelbert MD, PhD, Thomas H. Schindler MD, Leslee J. Shaw PhD, H. William Strauss MD, and Patrick White MPH

Tropolone: A Lipid Solubilizing Agent for Cationic Metals

Lipid soluble agents which chelate radioactive cations have several potential uses in nuclear medicine including: brain imaging, labeling of blood elements, and identifying fatty infiltration of organs. A tropolone-gallium complex has been characterized by the determination of in vitro partition ratios correlated with in vivo organ distribution in the rat. Partition ratios were determined for gallium-67 citrate, indium-114m chloride, and iron-59 chloride cations complexed with tropolone in chloroform+water, octanol+water, olive oil+water, and olive oil+plasma two-phased systems. Tropolone proved to be highly effective in the lipid solubilization of these metal cations. Distribution studies in animals of these cations complexed with tropolone demonstrated an increased concentration of these cation complexes in tissues of high lipid content when compared with appropriate controls.