18fluorodeoxyglucose positron emission tomography to detect mediastinal or internal mammary metastases in breast cancer

PURPOSE

To determine the prevalence of suspected disease in the mediastinum and internal mammary (IM) node chain by 18fluorodeoxyglucose (FDG) positron emission tomography (PET), compared with conventional staging by computed tomography (CT) in patients with recurrent or metastatic breast cancer.

PATIENTS AND METHODS

We retrospectively evaluated intrathoracic lymph nodes using FDG PET and CT data in 73 consecutive patients with recurrent or metastatic breast cancer who had both CT and FDG PET within 30 days of each other. In reviews of CT scans, mediastinal nodes measuring 1 cm or greater in the short axis were considered positive. PET was considered positive when there were one or more mediastinal foci of FDG uptake greater than the mediastinal blood pool.

RESULTS

Overall, 40% of patients had abnormal mediastinal or IM FDG uptake consistent with metastases, compared with 23% of patients who had suspiciously enlarged mediastinal or IM nodes by CT. Both FDG PET and CT were positive in 22%. In the subset of 33 patients with assessable follow-up by CT or biopsy, the sensitivity, specificity, and accuracy for nodal disease was 85%, 90%, and 88%, respectively, by FDG PET; 54%, 85%, and 73%, respectively, by prospective interpretation of CT; and 50%, 83%, and 70%, respectively, by blinded observer interpretation of CT. Among patients suspected of having only locoregional disease recurrence (n = 33), 10 had unsuspected mediastinal or IM disease by FDG PET.

CONCLUSION

FDG PET may uncover disease in these nodal regions not recognized by conventional staging methods. Future prospective studies using histopathology for confirmation are needed to validate the preliminary findings of this retrospective study.

Venous thrombosis and occlusion after pancreas transplantation: evaluation with breath-hold gadolinium-enhanced three-dimensional MR imaging

OBJECTIVE

We describe the imaging findings of venous thrombosis and occlusion after pancreatic transplantation in five patients who underwent multiphasic breath-hold gadolinium-enhanced three-dimensional MR imaging.

CONCLUSION

Venous thrombus appeared as serpetine voids within the graft parenchyma or at the venous anastomosis during the venous phase of MR imaging. Nonenhancement or heterogeneous enhancement of graft parenchyma corresponded to glandular necrosis at pancreatectomy in two patients. Initial sonographic evaluation was nondiagnostic of venous thrombosis in two of five patients. Multiphasic breath-hold gadolinium-enhanced three-dimensional MR imaging of pancreatic transplants can provide information to make the specific diagnosis of venous thrombosis or occlusion.

The presentation of gallstones and results of biliary surgery in a spinal cord injured population

BACKGROUND

Since spinal cord injured patients lack visceral sensation, their clinical manifestations of gallstones could be relatively occult. A higher proportion of these individuals may present with advanced biliary disease compared with the general population. Prophylactic cholecystectomy for asymptomatic stones may therefore be justified.

METHODS

All spinal cord injured patients seen at the Seattle Veterans Hospital over a 5-year period were retrospectively surveyed to define a set of patients who had undergone a cholecystectomy. The operative indications and results were compared with those from a series of cholecystectomies in neurologically intact patients.

RESULTS

The presentation of biliary disease in spinal cord injured patients was not more advanced than that of neurologically intact patients. Patients with high cord injuries presented in a similar fashion to those with low injuries.

CONCLUSIONS

Since most spinal cord injured patients with biliary disease present with typical findings, prophylactic removal of gallstones in these patients is not warranted.

The prevalence and natural history of gallstones in spinal cord injured patients

BACKGROUND

Individuals with a spinal cord injury are at increased risk for the development of gallstones. Because these patients cannot reliably manifest classic symptoms of biliary colic, they may be more likely to present with advanced biliary complications than patients with intact abdominal innervation. The natural history of gallstones in spinal cord injured patients has not been described.

STUDY DESIGN

All spinal cord injured patients seen at the Seattle Veterans Affairs Medical Center from January 1, 1993, to December 31, 1997 were included in the study. For each patient, the presence or absence of gallstones had been determined previously through screening abdominal ultrasonographic evaluations. Pertinent demographic information was obtained from medical records and patient interviews. Patients with gallstones were followed until death, cholecystectomy, or the conclusion of the study, and the annual incidence of biliary complications and patients requiring a cholecystectomy were determined. The prevalence of gallstones was established by studying the subset of patients seen at the Seattle Spinal Cord Injury Unit from January 1, 1995 to December 31, 1997.

RESULTS

Among the spinal cord injured patients, 31% either had gallstones or had undergone a cholecystectomy at some point after their injury. Increasing age, female gender, and greater severity of injury were risk factors for the formation of gallstones. Over the first 5 years after the diagnosis of gallstones, the annual incidence of cholecystectomy or biliary complications was 6.3% and 2.2%, respectively.

CONCLUSIONS

Spinal cord injured patients are at increased risk for the development of gallstones. Patients with gallstones are at an increased risk for the development of biliary complications compared with neurologically intact patients, but the magnitude of this risk does not warrant prophylactic cholecystectomy.

Imaging of oncologic patients: benefit of combined CT and FDG PET in the diagnosis of malignancy

OBJECTIVE

The purpose of this study was to assess the benefit of combined CT and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in diagnosing malignancy.

MATERIALS AND METHODS

The records of 26 patients with intraabdominal and intrathoracic neoplasms who underwent CT and FDG PET between January 1995 and September 1996 were retrospectively reviewed. Most of these patients had inconclusive findings on prior CT for the diagnosis of malignancy. Only sites of potential malignant disease were included in the data analysis. Presence or absence of malignancy was confirmed by histopathology or follow-up CT. Three observers experienced in abdominal imaging used CT findings alone to estimate level of suspicion (1 = definitely not malignant to 5 = definitely malignant) for primary or recurrent neoplasms (n = 21), distant metastases (n = 25), and neoplastic nodal involvement (n = 18). Six weeks later the three observers reviewed the same CT examinations supplemented with FDG PET and reestimated suspicion of malignancy. Receiver operating characteristic methodology was used to analyze the results. Sensitivity, specificity, positive and negative predictive values, and accuracy in diagnosis of malignant disease were calculated using level 4 (probable malignancy) as the cutoff for the presence of disease.

RESULTS

The mean area under the receiver operating characteristic curve, indicating successful diagnosis of malignancy, was .82 for CT alone and .92 for CT with FDG PET (p < .05). The accuracies for diagnosis of primary or recurrent neoplasms, distant metastases, and neoplastic nodal involvement were 62%, 68%, and 83%, respectively, for CT alone and 81% (p = .06), 88% (p = .03), and 89% (p > .25), respectively, for CT with FDG PET. Also, supplemental FDG PET imaging improved observer confidence and accuracy in diagnosing recurrent neoplasm in four (36%) of 11 patients who had undergone surgery or chemoradiation and in diagnosing four (29%) of 14 extrahepatic sites that had potential metastases.

CONCLUSION

Diagnosis of malignancy in oncologic patients is significantly improved when CT is supplemented with FDG PET. Combined imaging is particularly helpful in the evaluation of potential recurrence in previously treated patients and for diagnosing extrahepatic lesions that may be distant metastases.

Black blood magnetic resonance angiography with Dy-DTPA polymer: effect on arterial intraluminal signal intensity, lumen diameter, and wall thickness

Four rabbits in which atherosclerotic disease was induced by diet and balloon angioplasty underwent conventional angiography and MR angiography (MRA) using a black blood pulse sequence before and 10 minutes after the i.v. injection of a macromolecular contrast agent, NC 100283 (1.0 mmol/kg), a dysprosium diethylenetriaminepentaacetic acid hexamethylenediamine copolymer (Dy-DTPA polymer). Intraluminal signal intensity, apparent wall thickness, and lumen size measurements of the aorta and proximal common iliac arteries on precontrast MRA images were compared with postcontrast images. Aortic lumen diameter measurements on the precontrast and postcontrast MRA studies were compared with lumen diameters from conventional angiograms. Intraluminal signal intensity decreased on postcontrast MRA images compared with precontrast images, with an average loss of signal equal to 29% (P < .05). Apparent wall thickness decreased by 24% (P < .05). Lumen diameter and area were generally larger (average of 15% and 33%, respectively) on postcontrast MRA images than on precontrast images. Aortic lumen diameter measurements from postcontrast MRA agreed closely (95% confidence interval of the mean difference was -.2 to .3 mm), and precontrast MRA images tended to underestimate aortic lumen diameter (95% confidence interval of the mean difference was .3 to .8 mm) compared with conventional angiography. Postcontrast MRA with NC 100283, a macromolecular Dy-DTPA contrast agent, provides more accurate assessment of aortic lumen diameter than precontrast MRA, using conventional angiography as the standard reference.

Growth inhibition of axenic Entamoeba histolytica by tubercidin and ara-A

Several analogs of nucleic acid components including 7-deazaadenosine (tubercidin), adenine 9-beta-D-arabinofuranoside (ara-A), 8-azaguanine, 6-azathymine, 6-mercaptopurine, 6-mercaptopurine arabinoside, 6-mercaptopurine riboside and 1,3-dideazapurine (benzimidazole) were tested for inhibition of growth of an axenic strain of Entamoeba histolytica in 72 hour experiments. Metronidazole and emetine were included in the experiments for comparison. Tubercidin and ara-A, analogs of adenosine, were the most potent of the tested growth inhibitors with amebistatic concentrations of about 0.6 and 3.0 microM, respectively. The other analogs did not significantly inhibit amebal growth below 100 microM. In the present study metronidazole and emetine had amebistatic concentrations, respectively, 17- and 60-fold higher than tubercidin.