Improved retroperitoneal and gastrointestinal sonography using oral contrast agents in a porcine model

PURPOSE: To evaluate use of functional imaging with positron emission tomography (PET) versus computed tomography (CT) for detection of extranodal lymphoma spread. MATERIALS AND METHODS: Eighty-one consecutive and previously untreated patients with malignant non-Hodgkin lymphoma (n = 43) or Hodgkin disease (n = 38) were examined with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) PET and contrast material-enhanced CT. Concordant findings at both CT and FDG PET were regarded as actual locations of disease; discordant results were resolved on the basis of biopsy or follow-up results when possible. RESULTS: Forty-two lesions were identified at both PET and CT, and 19 were verified with biopsy results. PET demonstrated a further 24 lesions. Verification was possible in 15 of these lesions with biopsy (n = 10), magnetic resonance imaging (n = 1), scintigraphic (n = 1), or follow-up (n = 3) results. In 14 of these 15 lesions, PET findings were confirmed (bone marrow, nine; spleen, three; other, two). Seven lesions not visualized at FDG PET were identified at CT, six of which were verified with biopsy (n = 2) or follow-up (n = 4) results. Five of these six CT findings were found to be erroneous. In 13 patients, PET findings led to changes in tumor staging. CONCLUSION: PET may provide more information about extranodal lymphoma than does incremental CT.     

Fluorine-18 deoxyglucose positron emission tomography for the detection of bone metastases in patients with non-small cell lung cancer

Despite advances in morphological imaging, some patients with lung cancer are found to have non resectable disease at surgery or die of recurrence within a year of surgery. At present, metastatic bone involvement is usually assessed using bone scintigraphy, which has a high sensitivity but a poor specificity. We have attempted to evaluate the utility of the fluorine-18 deoxyglucose positron emission tomography (FDG PET) for the detection of bone metastasis. One hundred and ten consecutive patients with histological diagnosis of non-small cell lung cancer (NSCLC) who underwent both FDG PET and bone scintigraphy were selected for this review. In this group, there were 43 patients with metastatic disease (stage IV). Among these, 21 (19% of total group) had one or several bone metastases confirmed by biopsy (n = 8) or radiographic techniques (n = 13). Radionuclide bone scanning correctly identified 54 out of 89 cases without osseous involvement and 19 out of 21 osseous involvements. On the other hand, FDG PET correctly identified the absence of osseous involvement in 87 out of 89 patients and the presence of bone metastasis in 19 out of 21 patients. Thus using PET there were two false-negative and two false-positive cases. PET and bone scanning had, respectively, an accuracy of 96% and 66% in the evaluation of osseous involvement in patients with NSCLC. In conclusion, our data suggest that whole-body FDG PET may be useful in detecting bone metastases in patients with known NSCLC.     

Lymphoma: role of whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) PET in nodal staging

PURPOSE: To compare 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET) with computed tomography (CT) in primary nodal staging of malignant lymphoma. MATERIALS AND METHODS: Sixty consecutive patients with untreated, histopathologically proved malignant lymphoma (aged 7-72 years; 33 with non-Hodgkin lymphoma, 27 with Hodgkin disease) underwent FDG PET and contrast material-enhanced CT for nodal staging. Lymph node regions identified at both CT and PET were regarded as actual locations of disease. Discordant results were verified with biopsy or clinical follow-up whenever possible. RESULTS: One hundred sixty of 740 evaluated lymph node regions were identified as diseased at both CT and PET. Of the 25 additional regions seen with PET, seven were true-positive; two, false-positive; and 16, unresolved. CT showed six additional disease manifestations; three were false-positive, and three were unresolved. Staging was changed in the four patients with the seven confirmed additional PET findings: from stage I to II in one patient and from stage II to III in three patients. Staging was changed from stage II to I in one of the three patients with false-positive CT findings. CONCLUSION: FDG PET may be more accurate for detecting nodal lymphoma than incremental CT.     

Whole-body 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for accurate staging of Hodgkin's disease

BACKGROUND: Staging of Hodgkin's disease (HD) is accomplished by a variety of invasive and non-invasive modalities. This prospective study was undertaken to investigate the value of whole-body positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in defining regions involved by lymphoma compared with conventional staging methods in patients with HD. PATIENTS AND METHODS: Fourty-four newly diagnosed patients with HD underwent FDG-PET as part of their initial staging work-up. PET findings were correlated with findings of conventional staging including computed tomography, ultrasound, bone scanning, bone marrow biopsy, liver biopsy and laparotomy. When results of FDG-PET differed to those obtained by conventional methods reevaluation was performed by biopsy, if possible, or magnetic resonance imaging. RESULTS: The results of FDG-PET were compared with three hundred twenty-one conventional staging procedures performed in 44 patients. FDG-PET was positive in 38 of 44 (86%) patients at sites of documented disease. PET detected additional lesions in five cases previously not identified by conventional staging methods. In another case a nodal lesion suspect on CT was negative at FDG-PET and was settled as true negative by biopsy. As a consequence of PET findings five patients had to be upstaged and one patient had to be downstaged, resulting in changes in treatment strategy in all six cases (14%). FDG-PET failed to visualize sites of HD in four patients. In two of our patients a false positive PET result was obtained. CONCLUSIONS: Our data indicate that FDG-PET provides an imaging technique that appears to visualize involved lesions in most patients with HD and is useful in the management of these patients.     

Usefulness of FDG-PET in diagnosing primary lymphoma of the liver

This case report shows for the first time the usefulness of positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in the diagnosis of primary non Hodgkin's lymphoma of the liver. Results of FDG-PET, which in contrast to other imaging techniques offers the advantage of screening the whole body, demonstrated a high glycolytic activity of a solitary mass in the liver with central necrosis (loss of glycolytic activity), but no spread of lymphoma to the body. These results were confirmed by ultrasound, computed tomography, magnetic resonance imaging and were biopsy proven. From our findings we conclude that in patients with liver masses with high uptake of FDG, lack of liver dysfunction and absence of signs indicating other malignancies, a primary lymphoma of the liver should be considered as a possible diagnosis.     

Detection of bone metastases in breast cancer by 18FDG PET: differing metabolic activity in osteoblastic and osteolytic lesions

PURPOSE: 99mTechnetium methylene diphosphonate (99mTc MDP) bone scintigraphy is currently the method of choice for the detection of bone metastases, but 18F-fluoro-deoxy-D-glucose positron emission tomography (18FDG PET) offers superior spatial resolution and improved sensitivity. We have compared 18FDG PET with 99mTc MDP bone scintigraphy in patients with skeletal metastases from breast cancer and have analyzed the data in subgroups based on radiographic characteristics of lesions. PATIENTS AND METHODS: Twenty-three women with breast cancer and confirmed bone metastases were studied with both 99mTC MDP bone scintigraphy and 18FDG PET, and the number of lesions detected and the quantitation of uptake (standardized uptake values [SUVs]) of 18FDG in osteolytic and osteoblastic metastases were compared. Survival was compared for both lytic and blastic bone metastases and for patients with high and low accumulation of 18FDG. RESULTS: 18FDG PET detected more lesions than 99mTc MDP scintigraphy (mean, 14.1 and 7.8 lesions, respectively; P < .01). However, 18FDG detected fewer bone metastases compared with 99mTc MDP scintigraphy in a subgroup of patients with osteoblastic disease (P < .05). Higher SUVs were observed for osteolytic than osteoblastic disease (mean, 6.77 and 0.95, respectively; P < .01). Survival was lower in patients with osteolytic disease compared with the remainder (P=.01). A difference in survival was not found for those patients with high SUVs (> 3.6; P=.4). CONCLUSION: 18FDG PET is superior to bone scintigraphy in the detection of osteolytic breast cancer metastases, which led to a poorer prognosis. In contrast, osteoblastic metastases show lower metabolic activity and are frequently undetectable by PET. The biologic explanation for this observation remains to be elucidated.     

Identification of a novel antigenic structure of the human receptor for interleukin-6 involved in the interaction with the glycoprotein 130 chain

PURPOSE: To evaluate the diagnostic accuracy of positron emission tomography (PET) with administration of 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) relative to that of magnetic resonance (MR) imaging and/or computed tomography (CT) in recurrent head and neck cancers. MATERIALS AND METHODS: Twelve adult patients (mean age, 63 years) with previously treated head and neck cancers and clinical suspicion of recurrence underwent FDG PET and MR imaging and/or CT. All images were blindly and independently interpreted without histopathologic findings (obtained within 1 week of imaging). The level of confidence in image interpretation was graded by using a five-point rating system (0 = definitely no recurrence to 4 = definite recurrence). RESULTS: Recurrence was confirmed in eight patients. With a rating of 4 as a positive finding, FDG PET yielded a sensitivity and specificity of 88% (seven of eight) and 100% (four of four), respectively; MR imaging and/or CT, 25% (two of eight) and 75% (three of four), respectively. Receiver-operating characteristic analysis showed significantly better diagnostic accuracy with FDG PET than with MR imaging and/or CT (area under curve = 0.96 vs 0.55, P < .03). CONCLUSION: These data indicate that PET metabolic imaging, as compared with anatomic methods, has improved diagnostic accuracy for recurrent head and neck cancer.     

Evaluation of pancreatic tumors with positron emission tomography and F-18 fluorodeoxyglucose: comparison with CT and US

PURPOSE: To assess the clinical value of positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose (FDG) for identification of pancreatic carcinoma. MATERIALS AND METHODS: Forty-six patients suspected of having a pancreatic neoplasm and who were to undergo surgery prospectively underwent FDG PET, computed tomography (CT), and transabdominal ultrasound (US). Endoscopic US was performed in 40 patients. Images were independently interpreted and compared with the histopathologic findings at surgery (41 patients) or with clinical follow-up findings (five patients). RESULTS: In 33 of 35 patients, foci of pancreatic carcinomas (10-100 mm in diameter) were identified as an increase in FDG uptake, whereas CT, transabdominal US, and endoscopic US depicted the foci in 31, 31, and 28, cases, respectively. Among 11 benign lesions, nine showed no increased FDG uptake (specificity = 82%). Specificities of the other modalities were lower. False-positive findings were obtained in a case of chronic active pancreatitis and in a serous cystadenoma. CONCLUSION: FDG PET, which provides "biochemical" information, is accurate in identifying pancreatic carcinoma and may be a method of choice when imaging equivocal masses detected with other "anatomic" imaging studies.     

Complications in Paget disease at MR imaging

PURPOSE: To determine the MR imaging findings in patients with complications of Paget disease of bone. MATERIALS AND METHODS: Of 45 patients with Paget disease who underwent MR imaging, 33 (26 men, seven women; age range, 64-91 years) with known complications of the disease were examined. Imaging in this subgroup included radiography (n = 26), computed tomography (n = 12), bone scintigraphy (n = 15), and magnetic resonance (MR) imaging (n = 33). Patients were examined specifically for musculoskeletal and neurologic complications of Paget disease, including fracture, basilar impression, spinal stenosis, bone tumor, and osteoarthrosis. RESULTS: The 56 complications documented in the 33 patients were fracture (n = 17), neurologic entrapment (n = 19), neoplasm (n = 9), and arthropathy (n = 11). MR imaging was beneficial in the diagnostic evaluation of basilar impression (n = 7), spinal stenosis (n = 12), and the tumor stage (n = 9). It also helped to successfully evaluate pagetic bone narrowing of the coracoacromial arch, which was associated with impingement syndrome and rotator cuff rupture (n = 2). The signal intensities in pagetic bone were most commonly similar to those in fat; this finding had a 100% negative predictive value in excluding neoplasm. CONCLUSION: Although Paget disease is diagnosed economically with conventional radiography, MR imaging is well suited for demonstrating the presence and extent of several characteristic disease complications, including basilar impression, spinal stenosis, and secondary neoplasm.     

Chondroblastoma: classic and confusing appearance at MR imaging

PURPOSE: To define the characteristics of chondroblastoma at magnetic resonance (MR) imaging and the combination of findings that are diagnostic for chondroblastoma. MATERIALS AND METHODS: From January 1987 through December 1992, 22 patients with histologically confirmed chondroblastoma and prior MR imaging examinations were seen. Patients included 16 men and six women, aged 10-58 years (median, 17 years). Retrospective analysis of findings at MR imaging, plain radiography, computed tomography, and bone scanning was performed. RESULTS: Low to intermediate heterogeneous signal intensity, lobular internal architecture, and fine lobular margins were well defined with high-resolution T2-weighted (repetition time > or = 1,500 msec, echo time > or = 70 msec) MR imaging. Adjacent bone-marrow and soft-tissue edema and periosteal reactions were more dramatically demonstrated on MR images than on radiographs. Bone marrow edema was prominent in all but five cases. Obvious periosteal reaction and adjacent soft-tissue edema were visible in 17 cases. CONCLUSION: Knowledge of the MR imaging findings of chondroblastoma will allow accurate diagnosis and help avoid confusion with infection and aggressive neoplasms.     

Fluorine-18-FDG PET and technetium-99m antigranulocyte antibody scintigraphy in chronic osteomyelitis

The aim of this study was to assess the usefulness of PET with 2-18F-fluoro-2-deoxy-D-glucose (FDG), as compared to immunoscintigraphy (IS) with 99mTc-labeled monoclonal antigranulocyte antibodies (AGAbs), in the detection of chronic osteomyelitis. METHODS: Fifty-one patients suspected of having chronic osteomyelitis in the peripheral (n = 36) or central (n = 15) skeleton were evaluated prospectively with static FDG PET imaging and combined 99mTc-AGAb/99mTc-methylene diphosphonate (MDP) bone scanning within 5 days. FDG PET and IS were evaluated in a blinded and independent manner by visual interpretation, which was graded on a five-point scale of two observers' confident diagnosis of osteomyelitis. Receiver operating characteristic (ROC) curve analysis was performed for both imaging modalities. The final diagnosis was established by means of bacteriologic culture of surgical specimens and histopathologic analysis (n = 31) or by biopsy and clinical follow-up over 2 yr (n = 20). RESULTS: Of 51 patients, 28 had osteomyelitis and 23 did not. According to the unanimous evaluation of both readers, FDG PET correctly identified 27 of the 28 positives and 22 of the 23 negatives (IS identified 15 of 28 positives and 17 of 23 negatives, respectively). The area under the ROC curve was 0.97/0.97 (reader 1/reader 2) for FDG PET and 0.87/0.90 for IS, with a high degree of interobserver concordance (K-values were 0.96 for FDG PET and 0.91 for IS). In the central skeleton, the ROC curve area was 0.98/1.00 for FDG PET and 0.71/0.77 for IS (p<0.05). On the basis of ROC analysis, the overall accuracies of FDG PET and IS in the detection of chronic osteomyelitis were 96%/96% and 82%/ 88%, respectively. With regard to the optimal threshold values, sensitivity and specificity were 100%/97% and 95%/95% with FDG PET, compared to 86%/92% and 77%/82% with IS, respectively. CONCLUSION: In the peripheral skeleton, both FDG PET and combined 99mTc-AGAb/99mTc-MDP scanning are appropriate imaging modalities to diagnose chronic osteomyelitis. FDG PET additionally allows reliable differentiation between osteomyelitis and infection of the surrounding soft tissue. In the central skeleton within active bone marrow, FDG PET is highly accurate and superior to AGAb imaging in the diagnosis of chronic osteomyelitis, which frequently presents as a nonspecific photopenic lesion at scintigraphy with labeled white blood cells.     

Assessment of axillary lymph node involvement in breast cancer patients with positron emission tomography using radiolabeled 2-(fluorine-18)-fluoro-2-deoxy-D-glucose

BACKGROUND: The presence of metastatic tumor cells in the axillary lymph nodes is an important factor when deciding whether or not to treat breast cancer patients with adjuvant therapy. Positron emission tomography (PET) imaging with the radiolabeled glucose analogue 2-(fluorine-18)-fluoro-2-deoxy-D-glucose (F-18 FDG) has been used to visualize primary breast tumors as well as bone and soft-tissue metastases. PURPOSE: This study was undertaken to evaluate before surgery the diagnostic accuracy of PET for detection of axillary lymph node metastases in patients suspected of having breast cancer. METHODS: Women who were scheduled to undergo surgery for newly discovered, suspected breast cancers were referred for PET imaging of the axilla region. The women were first clinically examined to determine the status of their axillary lymph nodes (i.e., presence or absence of metastases). Fifty-one women were intravenously administered F-18 FDG and were studied by PET imaging. Attenuation-corrected transaxial and coronal images were visually evaluated by two nuclear medicine physicians (blinded to the patient's medical history) for foci of increased F-18 FDG uptake in the axilla region. All patients underwent surgery for their suspected breast cancers. Axillary lymph node dissection was also performed on all patients with breast cancer, with the exception of four patients who received primary chemotherapy for locally advanced breast cancer. A single pathologist analyzed breast tumor and lymph node tissue specimens. RESULTS: The overall sensitivity (i.e., the ability of the test to detect disease in patients who actually have disease) and specificity (i.e., the ability of the test to rule out disease in patients who do not have disease) of this method for detection of axillary lymph node metastases in these patients were 79% and 96%, respectively. When only patients with primary breast tumors larger than 2 cm in diameter (more advanced than stage pT1; n = 23) were considered, the sensitivity of axillary PET imaging increased to 94%, and the corresponding specificity was 100%. Lymph node metastases could not be identified in four of six patients with small primary breast cancers (stage pT1), resulting in a sensitivity of only 33%. Axillary PET imaging provided additional diagnostic information in 12 (29%) of 41 breast cancer patients with regard to the extension of disease to other sites (i.e., other lymph nodes, skin, bone, and lung). CONCLUSIONS: PET imaging with F-18 FDG allowed accurate and noninvasive detection of axillary lymph node metastases, primarily in patients with breast cancer more advanced than stage pT1. Detection of micrometastases and small tumor-infiltrated lymph nodes is limited by the currently achievable spatial resolution of PET imaging. IMPLICATIONS: In clinical practice, PET imaging cannot substitute for histopathologic analysis in detecting axillary lymph node metastases in breast cancer patients. PET imaging, however, improves the preoperative staging of the disease in breast cancer patients and, therefore, might alter therapeutic regimen options.     

Magnetic resonance imaging of renal lymphoma with computed tomography correlation

The magnetic resonance (MR) imaging and computed tomography (CT) findings in four patients (five kidneys) with non-Hodgkin's lymphoma involving the kidneys and perirenal spaces are presented. The patterns of disease in each case were as follows: bilateral renal nodules, infiltration in the perirenal space, infiltration in the perirenal space with renal involvement, and direct invasion from contiguous retroperitoneum. On plain CT, the lesions showed slight hyperdensity (three kidneys) and isodensity (two kidneys) as compared with normal renal parenchyma. But all lesions appeared as hypodense masses with more definite margins after contrast enhancement. MR imaging findings showed iso- or slight hypointense masses on T1-weighted images and definite hypointense masses on T2-weighted images as compared with the signal intensity of the renal cortex. Dynamic imaging and conventional delayed T1-weighted imaging following Gd-DTPA injection showed no significant enhancement of the lesions. In comparison with contrast enhanced CT, despite its poorer resolution, T2-weighted MR imaging showed nearly the same accuracy in the evaluation of number and extent of the lesions without contrast medium administration. MR imaging was also useful to evaluate the patency of vessel lumen surrounded by tumor mass and to determine the location and extent of huge lesions by its multiplanar imaging capabilities.     

Comparison of fluorine-18 fluorodeoxyglucose positron emission tomography and technetium-99m methoxyisobutylisonitrile scintimammography in the detection of breast tumours

The aim of this study was to compare, in breast cancer patients, the diagnostic accuracy of positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) and scintimammography (SMM) using technetium-99m methoxyisobutylisonitrile (MIBI). A total of 20 patients (40 breasts with 22 lesions) were evaluated serially with MIBI and, on the following day, with FDG. For SMM, planar and single-photon emission tomography imaging in the prone position was performed starting at 10 min following the injection of MIBI (740 MBq). For PET, scans were acquired 45-60 min after the injection of FDG (370 MBq) and attentuation correction was performed following transmission scans. Results from SMM and PET were subsequently compared with the histopathology results. True-positive results were obtained in 12/13 primary breast cancers (mean diameter=29 mm, range 8-53 mm) with both FDG and MIBI. False-negative results were obtained in two local recurrences (diameter <9 mm) with both FDG and MIBI. In benign disease, FDG and MIBI did not localize three fibrocystic lesions, two fibroadenomas and one inflammatory lesion (true-negative), but both localized one fibroadenoma (false-positive). Collectively, the results demonstrate a sensitivity of 92%, and a specificity of 86%, for primary breast cancer regardless of whether FDG or MIBI was used. In contrast to MIBI scintigraphy, FDG PET scored the axillae correctly as either positive (metastatic disease) or negative (no axillary disease) in all 12 patients. The tumour/non-tumour ratio for MIBI was 1.97 (range 1.43-3.1). The mean standard uptake value (SUV) for FDG uptake was 2.57 (range 0.3-6.2). The diagnostic accuracy of SMM was equivalent to that of FDG PET for the detection of primary breast cancer. For the detection of in situ lymph node metastases of the axilla, FDG seems to be more sensitive than 99mTc-MIBI.     

Whole-body [18F]FDG PET in the management of metastatic brain tumours

BACKGROUND: To determine its roles in the diagnosis and the systemic evaluation of metastatic brain tumours, whole-body positron emission tomography (PET) using [18F]FDG was performed in 20 consecutive patients. METHODS: All patients were thought to be suffering or needing to be differentiated from metastatic brain tumours. Nine patients had multiple brain lesions; six were older and showed a rim-enhancing lesion with surrounding oedema; seven had homogeneously enhancing periventricular lesion(s) on computed tomography (CT) and/or magnetic resonance (MR) imaging, thought to be central nervous system lymphomas. Two patients had skull mass(es) and two patients had a solid mass suspected to be, respectively, a haemorrhagic metastasis and a metastatic malignant melanoma. All of them received whole-body [18F]FDG PET and conventional systemic work-up for metastasis in order to compare the results of the two methods. RESULTS: Metastatic brain tumours were diagnosed on whole-body [18F]FDG PET in eleven patients who had extracranial and intracranial hypermetabolic lesions. In nine of these, a conventional work-up also detected primary lesions which on whole-body [18F]FDG PET were seen to be hypermetabolic foci. Systemic lymph node metastases were detected by whole-body [18F]FDG PET only in two patients and histological diagnosis was possible by biopsy of lymph nodes rather than of brain lesions. In the remaining nine patients who had only intracranial hypermetabolic foci, histological diagnosis was made by craniotomy or stereotactic biopsy. It was confirmed that seven of nine patients were suffering from a primary brain tumour and two from metastatic carcinoma. None of the nine showed evidence of systemic cancer on conventional work-up. Histological diagnoses of the primary brain tumours were four cases of primary central nervous system lymphoma and one each of multifocal glioblastoma, Ewing's sarcoma, and cavernous angioma. Patients felt no discomfort during the whole-body [18F]FDG PET procedure and there were no complications. The false negative rate in [18F]FDG PET and in conventional work-up was 15.4% and 30.7% respectively. There were no false positives on either [18F]FDG PET or conventional work-up. CONCLUSION: It is suggested that whole-body [18F]FDG PET is a safe, reliable, and convenient method for the diagnosis and systemic evaluation of patients thought to be suffering or needing to be differentiated from a metastatic brain tumour.     

Uremic leontiasis ossea: "bighead" disease in humans? Radiologic, clinical, and pathologic features

PURPOSE: To describe the clinical, radiologic, and pathologic findings in patients with uremic leontiasis ossea (ULO). MATERIALS AND METHODS: Five patients with renal osteodystrophy developed marked hyperostosis of the facial and cranial bones. Radiologic studies included plain radiography of the skull (n = 5), computed tomography with three-dimensional reconstruction (n = 4), magnetic resonance imaging (n = 3), and fluorine-18 sodium fluoride positron emission tomography (PET) (n = 1). Specimens from bone biopsies (three patients) were examined. RESULTS: Skull and facial alterations were remarkably similar. Numerous nodules of varying attenuation and signal intensity in the widened diploic space suggested brown tumors in different stages of evolution. Biochemical data and PET findings enabled confirmation of markedly increased bone turnover. Bone specimens demonstrated severe osteitis fibrosa. After parathyroidectomy, facial changes in all patients stabilized or improved mildly. CONCLUSION: A similar entity in animals, "bighead" disease, which results from nutritional and uremic secondary hyperparathyroidism, may provide a useful animal model for ULO in humans. Mild forms of this entity may be more common than the scarcity of previous reports suggests.     

FDG PET in head and neck cancer

In our extensive experience with FDG PET imaging in head and neck cancer, we have found the technique to be of high accuracy but of limited usefulness. This seeming paradox arises from several causes. Competing techniques such as CT, MR imaging, and even clinical examination already have good accuracy. In addition, high-resolution studies such as CT and MR imaging provide information required for treatment planning that is unavailable from FDG PET images. The high cost of FDG PET militates against its use in this setting, in which only a small marginal gain can be expected. In the special problem areas in which FDG PET might be expected to offer unique advantages, such as screening for second primary lesions, searching for unknown primary lesions, or differentiating benign salivary rumors from malignant lesions, the results of FDG PET have been disappointedly poor. Of these special problem areas, only the question of accuracy in finding occult primary lesions appears unresolved and in need of further study. The single application in which FDG PET appears to be advantageous is the posttherapy setting. In this setting, the technique is definitely superior to alternative methods of determining tumor recurrence and differentiating posttherapy sequelae such as radiation necrosis from tumor recurrence. We believe that considerable opportunity remains for further research on the use of FDG PET in head and neck cancer. Other agents such as 11C-methionine for example, might improve the diagnostic accuracy of FDG PET in some of the problem areas that we have identified, such as the early postirradiation period. We currently have such a study under way. Also, because FDG PET offers a unique way to measure tumor metabolism, further investigation of the use of FDG PET tracers to evaluate various biologic parameters such as proliferation rates or tumor hypoxia are needed. Such studies could provide a noninvasive technique to identify which fractionation schemes or combinations of therapy might be useful for individual patients. A final caveat is in order. Although our findings of the usefulness (and lack thereof) of FDG PET in head and neck cancer may be disappointing to many, these results should not be generalized to other applications of FDG PET in oncology. Each tumor type and setting presents its own specific problems, and in some instances FDG PET offers unique advantages over other imaging techniques. A good example is the setting of primary lung cancer, in which FDG PET appears clearly superior to all other methods of pretherapy screening [19-20].     

Design of an isolated pig heart preparation for positron emission tomography and magnetic resonance imaging

RATIONALE AND OBJECTIVES: Validation of new positron emission tomography (PET) tracers or magnetic (MR) imaging contrast agents is based on isolated rodent heart preparations. The use of larger animals could provide a more direct validation using the devices used for humans. METHODS: An isolated pig heart preparation has been developed and adapted to the technical constraints of whole body PET and MR imaging. This preparation could be used either in the Langendorff or working mode after selective cannulation of both coronary arteries. RESULTS: The authors showed that quantification of regional kinetics of PET tracers was possible using this preparation by measuring fluorine-18-labeled deoxyglycose (18FDG) kinetics in remote and ischemic territories. Experiments using MR imaging contrast agents, for myocardial perfusion, demonstrated the ability of this preparation to accurately validate these contrast agents over a wide range of flow rates. CONCLUSIONS: An isolated pig heart preparation could be developed to fulfill the constraints of PET and MR imaging, and proved useful for the study of the distribution of different tracers or contrast media developed for functional cardiac imaging in humans.     

Bone marrow uptake of fluorine-18-fluorodeoxyglucose following treatment with hematopoietic growth factors: initial evaluation

Hematopoietic growth factors (HGF) such as G-CSF and GM-CSF stimulate cell growth of the bone marrow and thereby mitigate the myelotoxic effect of chemotherapy. Using 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) for therapy response monitoring of patients with small-cell lung cancer, both an extension and an intensification of thoracic bone marrow uptake were noted in patients treated with HGF (n = 5) compared to those patients without HGF supplementation (n = 11). FDG uptake was a very sensitive marker of stimulated hematopoiesis, and both the extension and the intensification of uptake have to be noted during HGF therapy.     

Findings at mammographic screening on only one standard projection: outcomes analysis

PURPOSE: To compare thallium-201 scintigraphy with gallium-67 scintigraphy in the detection of residual or recurrent mediastinal Hodgkin disease after treatment. MATERIALS AND METHODS: The authors performed planar Ga-67 and Tl-201 scintigraphy in 39 patients aged 7-18 years (27 with mediastinal primary disease) after primary treatment. These scans and those in a control group of 14 patients with newly diagnosed known mediastinal Hodgkin disease were evaluated independently by two radiologists for abnormal mediastinal activity. Results were compared with chest computed tomographic (CT) findings and with the clinical criteria of disease status. Interobserver agreement and consensus agreement on gallium and thallium scan findings were evaluated with the kappa statistic, and the specificity of the two imaging methods was analyzed. RESULTS: All study patients were judged to be free of mediastinal disease with CT and the clinical criteria. Interobserver agreement on findings in the treated and control patients was stronger with gallium scintigraphy (kappa +/- SD = 0.956 +/- 0.044) than with thallium scintigraphy (kappa = 0.638 +/- 0.110). Specificity of ratings based on thallium (85% +/- 6) and gallium (90% +/- 5) scintigraphic findings of mediastinal disease did not differ significantly (P = .48). Specificity improved when the results of the two examinations were combined (97% +/- 2). CONCLUSION: Thallium scintigraphy can help to predict the absence of mediastinal Hodgkin disease after treatment.