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G J Cook

Publications and source records attributed to G J Cook.

At least 37 records · Page 2Linked to original sources
PubMed1998

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.

Adult↗
PubMed1998

[11C]Methionine positron emission tomography for patients with persistent or recurrent hyperparathyroidism after surgery.

OBJECTIVE: Reoperation in patients with recurrent hyperparathyroidism usually requires localisation of abnormal glands. Current imaging techniques are not always successful in this group of patients. An evaluation of [11C]methionine positron emission tomography (PET) has been made to assess the ability of the technique to localise abnormal glands in patients with hyperparathyroidism after previous surgery. SUBJECTS AND METHODS: Eight patients (five with primary, and three with tertiary hyperparathyroidism) who had undergone one to three previous surgical explorations were studied. [11C]methionine PET scans of the neck and mediastinum were performed in all patients. All had recent technetium-99m (99mTc)-labelled sestamibi (n = 7) or thallium-201 (201Tl)/99mTc subtraction (n = 1) parathyroid scans available for comparison. Subsequent surgical correlation was available in all cases. RESULTS: [11C]methionine PET correctly located an abnormal site of uptake in all five patients with primary hyperparathyroidism compared with only one when conventional nuclear medicine methods were used. In the patients with tertiary hyperparathyroidism, [11C]methionine PET correctly located one, confirmed the absence of cervical or mediastinal abnormality in a patient with an autotransplanted forearm autonomous gland, and failed to demonstrate an abnormality in a third. 99mTc-labelled sestamibi scans were negative in all three patients. CONCLUSION: [11C]methionine PET correctly locates abnormal parathyroid glands in the majority of patients with persistent or recurrent hyperparathyroidism after surgery in whom conventional non-invasive nuclear medicine imaging has failed.

Adenoma↗
PubMed1998

Technetium-99m-labeled HL91 to identify tumor hypoxia: correlation with fluorine-18-FDG.

UNLABELLED: Technetium-99m HL91 is a potential agent for imaging hypoxic tissue in vivo. A pilot evaluation using a prototype formulation assessed efficacy in tumor imaging and compared results with 18F-fluorodeoxyglucose (FDG) PET. METHODS: Ten patients with malignant tumors were included. Tumors included carcinoma of the bronchus (n = 3), carcinoma of the thyroid (n = 2), lymphoma (n = 2), soft tissue sarcoma (n = 1), carcinoid (n = 1) and carcinoma of the breast (n = 1). Whole-body planar scans and localized SPECT scans were performed at 1 and 4 hr postinjection of 600 MBq 99mTc HL91. Half-body and localized emission/transmission 18F-FDG PET scans were performed 60 min postinjection 370 MBq 18F-FDG in eight patients. Lesion-to-normal tissue background ratios were measured for all 99mTc HL91 and 18F-FDG PET scans and percentage uptake and standardized uptake values measured for 99mTc HL91 and 18F-FDG PET, respectively. RESULTS: Technetium-99m HL91 showed visible uptake into the tumor area in all seven studies where the tumor was clearly identified by 18F-FDG PET; 99mTc HL91 uptake was not detected in one study (carcinoid) in which 18F-FDG was weakly positive. Two further tumors, in which PET correlation was not available, showed accumulation of 99mTc HL91. In two 99mTc HL91 studies, abnormality was apparent only on SPECT images. Lesion-to-normal tissue background ratios for 99mTc HL91 ranged from 1.22/2.53 at 1 hr and 1.33/2.89 at 4 hr on planar images and 1.23/5.2 and 1.67/14.6 on SPECT images, respectively. CONCLUSION: In this study, the use of 99mTc HL91 resulted in uptake in the majority of malignant tumors identified by 18F-FDG-PET. Technetium-99m HL91 exhibits good imaging characteristics, with imaging at 4 hr providing good lesion-to-normal tissue background ratios, that are further enhanced by SPECT.

Aged↗
PubMed1997

Hepatic artery thrombosis and infarction: evolution of the ultrasound appearances in liver transplant recipients.

Hepatic infarction is a serious complication of liver transplantation, causing significant morbidity and mortality and often requiring retransplantation. Real time ultrasonography with Doppler examination is often the first imaging modality employed to investigate post-operative complications. We report on the sonographic appearances of three patients in whom hepatic infarction followed transplantation but who did not require retransplantation, allowing us to study the evolution of sonographic features. Geographic areas of decreased echogenicity with preservation of the portal tracts are an early sign of hepatic ischaemia and may either resolve completely or progress to true infarction with the development of transient small hyperechoic lesions. Calcification may also occur quite rapidly. Biliary strictures, bilomas and abscess formation are later complications.

Adolescent↗
PubMed1997

Fluorine-18-FDG PET in Paget's disease of bone.

UNLABELLED: Paget's disease of bone is common in the elderly and is associated with increased osteoblastic and osteoclastic activity at affected sites in the skeleton. It is not known whether this high metabolic activity is associated with increased glycolysis and, hence, uptake of [18F]FDG. The appearances of Paget's disease with [18F]FDG PET have not been described and it is not known whether Paget's may cause false-positive studies in those undergoing oncological staging or whether [18F]FDG PET can reliably differentiate benign pagetic change from osteosarcoma that may complicate Paget's disease. We reviewed [18F]FDG PET scans in patients with uncomplicated Paget's disease and documented its appearances. METHODS: Eighteen patients with established Paget's disease and typical radiological features had 99mTc-MDP bone scans and [18F]FDG PET scans performed. Serum alkaline phosphatase (ALP) was also measured. RESULTS: All patients showed high uptake of MDP in affected bones. Of the 18 patients only six showed any uptake of [18F]FDG. This occurred in some but not all bones shown to be involved on MDP bone scans. Three patients demonstrated low-grade uptake and three showed marked accumulation of [18F]FDG. The [18F]FDG-positive group had higher serum ALP levels than the [18F]FDG-negative patients (p < 0.05). CONCLUSION: Paget's disease of bone is not associated with abnormal [18F]FDG uptake in the majority of patients and, therefore, there is potential for discriminating between benign Paget's disease and associated Paget's sarcoma. However, low-grade uptake may be seen in patients with more active disease as measured by ALP. Rarely, marked uptake of [18F]FDG may be seen and Paget's disease should be included as a possible cause of false-positive scans in elderly patients who are being assessed for metastatic disease.

Aged↗
PubMed1996

Lateral collateral ligament tear of the knee: appearances on bone scintigraphy with single-photon emission tomography.

We report two cases, with magnetic resonance imaging correlation, of acute lateral collateral ligament tear of the knee following trauma with findings on bone scintigraphy with single-photon emission tomography (SPET). The typical bone scan features are presented. In addition, the advantages of the use of SPET in the detection of associated lesions are discussed.

Adult↗
PubMed1996

Normal physiological and benign pathological variants of 18-fluoro-2-deoxyglucose positron-emission tomography scanning: potential for error in interpretation.

The use of positron-emission tomography in clinical practice is increasing, particularly with the use of 18-fluoro-2-deoxyglucose (FDG) for oncological studies. As in other imaging modalities, it is important to be aware of normal variants and benign diseases that may mimic more serious pathology. Uptake of FDG in a number of sites may be variable. Uptake of FDG may be seen normally in the skeletal muscle after exercise or under tension, in the myocardium, in parts of the gastrointestinal tract, especially the stomach and cecum, and in the urinary tract. Some causes of increased physiological uptake are avoidable, and measures can be taken to minimize accumulation, thus aiding study interpretation. Inflammatory lesions may cause an increase in FDG uptake, but not usually to the same degree as malignancy. Benign disease such as Paget's disease of bone, sarcoidosis, and tuberculosis may cause uptake that occasionally mimics that of malignancy. Typical examples of a number of physiological and benign variants are described and illustrated.

Artifacts↗
PubMed1996

SPECT bone scintigraphy of anterior cruciate ligament injury.

UNLABELLED: This retrospective analysis of SPECT bone scans of the knee was undertaken to define typical bone scan appearances and to assess the sensitivity of this method. We looked at 14 patients, mostly with chronic knee pain, who had anterior cruciate ligament (ACL) tears detected by MRI. METHOD: Of the 14 patients, 10 were referred for bone scanning following injury and 4 complained of chronic knee pain without injury. Planar scans were performed 4 hr after the injection of 750 MBq of 99mTc-MDP. Tomographic images were obtained by a 64 x 20-sec acquisition over 360 degrees using a high-resolution collimator. MRI imaging included axial and sagittal, T1 weighted and coronal fast field echo (FFE) sequences. Ten patients also had arthroscopy performed. RESULTS: MRI scans showed 6 lone ACL tears and 8 combined with other ligamentous injuries. SPECT scans showed abnormalities in 10 patients in the region of ACL insertions but only 4 planar studies were abnormal. SPECT identified focal activity at the upper (n = 8) or lower (n = 2) insertion of the ACL. Six of 10 arthroscopies confirmed ACL tears, 2 complete and 4 partial. Overall, agreement was found with MRI in 10 of 14 cases and in 8 of 10 with arthroscopy. Abnormalities were identified in 10 of 11 regions of other ligament or bone injury identified by MRI. CONCLUSION: SPECT bone scanning of the knee is superior to planar imaging in detecting ACL injury and is a sensitive technique. Focal activity may be seen at either end of ACL attachment but more commonly at the upper femoral insertion. Knee SPECT may be a valuable examination in suspected ACL injury, particularly if MRI is not available, is equivocal or where clinical signs are absent.

Adult↗
PubMed1996

Pseudo pulmonary embolism in complex congenital heart disease.

Two children (aged 12 and 14 yr) with a history of complex congenital heart disease presented with symptoms and signs suggestive of pulmonary embolism. Initial ventilation-perfusion lung scans showed normal, approximately equal ventilation to both lungs. Global reduction of perfusion to the right lung was observed in one and was observed in the left lung in the other patient. It was not possible to exclude a large, central embolus in either case. Due to complex cardiac anatomy, however, which included bilateral cavopulmonary anastomoses in the first patient and SVC-right pulmonary artery and right atrial-pulmonary artery anastomoses in the second, repeat scans were performed within a short period in each case with different injection sites, including the contralateral arm and a leg injection, respectively. In both patients, these follow-up scans showed a different perfusion agent distribution to each lung when compared to the initial scans. These results demonstrated that there was no evidence of pulmonary embolism in either case.

Adolescent↗
PubMed1995

An evaluation of 99Tcm-DMSA SPET with three-dimensional reconstruction in 68 patients with varied renal pathology.

Sixty-eight patients (135 kidneys) with varied renal pathology were evaluated with 99Tcm-dimercaptosuccinic acid (DMSA) single photon emission tomography (SPET) to determine whether it is possible to detect more renal abnormalities and to reduce the number of false-positives due to anatomical variants when compared with planar imaging. The patients ranged in age from 1 to 78 years and their pathologies included urinary tract infection (n = 50), space occupying lesions (n = 5), calculi (n = 4), hypertension (n = 4) and others (n = 5). Planar scans were performed 3 h after the injection of 80 MBq of 99Tcm-DMSA and a 64 x 20 s acquisition over 360 degrees was used for SPET. High-resolution collimation was used for both. Slices were displayed as transaxial, coronal and sagittal and/or oblique sagittal in the plane of the kidney. Three-dimensional (3D) images were formed by volume rendering. Each kidney was divided into three regions and each region scored separately for the presence of an abnormality. Planar scans were reviewed alone and then in conjunction with SPET and 3D images. Planar imaging detected 95 abnormal regions compared with 103 using SPET. SPET reduced the number of equivocal regions in 8 (12%) patients. The diagnosis was altered by SPET in 17 (4%) regions in 14 (21%) patients. SPET and 3D 99Tcm-DMSA allow more abnormalities to be detected but also allow more specific definition of apparent abnormalities on planar imaging.

Adolescent↗