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Rachel Bar-Shalom

Publications and source records attributed to Rachel Bar-Shalom.

At least 19 recordsLinked to original sources
PubMed2006

The role of FDG-PET/CT in suspected recurrence of breast cancer.

BACKGROUND: Early diagnosis of recurrent breast cancer is crucial to selection of the most appropriate therapy. The current study evaluated the role of FDG-PET/CT in the assessment of suspected recurrent breast cancer in patients who presented with elevated serum tumor markers. METHODS: Forty-seven consecutive FDG-PET/CT studies of 46 women (aged 32-79 years; mean, 59.9 years) with a history of breast cancer presented with elevated serum tumor markers 1-21 years (mean = 6.2 years) after their initial diagnosis and were retrospectively evaluated. PET/CT results were confirmed by pathology (n = 11), further imaging, and follow-up (mean = 17.2 months; n = 36). Changes in further management based on PET/CT were recorded. RESULTS: Thirty (65%) patients had tumor recurrence, and 16 (35%) patients showed no further evidence of disease. Thirty-one patients had 32 abnormal PET/CT studies, and 15 patients had normal studies with an overall sensitivity, specificity, and accuracy of 90%, 71%, and 83%, respectively. In 37 patients, PET/CT was compared with contrast-enhanced CT and had a higher sensitivity (85% vs 70%), specificity (76% vs 47%), and accuracy (81% vs 59%). PET/CT had an impact on the management of 24 (5l%) patients. Of these, chemotherapy or radiotherapy was started in 16 patients, treatment was modified in 2 patients, and 6 patients were referred to biopsy, followed by referral to surgery for 2 patients. CONCLUSIONS: In patients with breast cancer and rising tumor markers, FDG-PET/CT had high performance indices and was superior to CT for diagnosis of tumor recurrence, which led to changes in the subsequent clinical management of 51% of these patients.

Adult↗
PubMed2006

A hybrid algorithm for PET/CT image merger in hybrid scanners.

PURPOSE: To improve the PET image quality of a hybrid PET/CT scanner by merging CT borders with PET texture. PET/CT scanners provide both high-resolution CT images showing anatomical details and PET images of low-resolution physiological information about radiopharmaceutical uptake. Standard smoothing of noisy PET images may further impair PET resolution, reducing small lesion detectability. METHODS: The CT edge data and the PET texture data were merged using a modified form of an algorithm called HCT (hybrid computed tomography). In merged PET/CT images, each PET pixel value was estimated by iteratively applying a corrected 2D Taylor expansion to each of its eight neighbors. The spatial derivative term was used only near anatomical edges provided by the CT. This counts-preserving algorithm was tested on a special resolution phantom and patient data sets obtained by PET/CT acquisitions. RESULTS: The HCT algorithm provided phantom PET images with sharp borders and improved resolution (< or = 3 mm as compared to > or = 4 mm). HCT increased the signal to background contrast ratios by an average of 61% (40-89%) while maintaining noise reduction similar to the Gaussian filtering standard in PET. In the clinical PET images, HCT allowed for an improved delineation of pulmonary and pelvic lesions and an improved visualization of the brain. CONCLUSION: A new reconstruction algorithm for merging CT anatomical edge data with functional PET data has been introduced. The algorithm smooths noisy PET images while retaining sharper edges at corresponding anatomical borders, resulting in an improvement in resolution and contrast ratio.

Algorithms↗
PubMed2006

The incremental value of 18F-FDG PET/CT in paediatric malignancies.

PURPOSE: (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) imaging has been used in the assessment of paediatric malignancies. PET/CT increases the diagnostic accuracy in adult cancer patients. The present study assesses the incremental value of FDG PET/CT in paediatric malignancies. METHODS: A total of 118 (18)FDG PET/CT studies of 46 paediatric patients were reviewed retrospectively. PET and PET/CT results were classified as malignant, equivocal or benign, compared on a site- and study-based analysis, and also compared with the clinical outcome. RESULTS: Three hundred and twenty-four sites of increased FDG uptake were detected. Discordant PET and PET/CT interpretations were found in 97 sites (30%) in 27 studies (22%). PET yielded a statistically significant higher proportion of equivocal and a lower proportion of benign lesion and study results (p<0.001) than PET/CT. With PET there were 153 benign (47%), 84 (26%) equivocal and 87 (27%) malignant sites, while PET/CT detected 226 benign (70%), 10 (3%) equivocal and 88 (27%) malignant lesions. PET/CT mainly improved the characterisation of uptake in brown fat (39%), bowel (17%), muscle (8%) and thymus (7%). The study-based analysis showed that 17 equivocal and seven positive PET studies (20%) were interpreted as benign on PET/CT, while three equivocal studies were interpreted as malignant. The study-based sensitivity and specificity of PET/CT were 92% and 78% respectively. CONCLUSION: PET/CT significantly improved the characterisation of abnormal (18)FDG foci in children with cancer, mainly by excluding the presence of active malignancy in sites of increased tracer activity.

Adolescent↗
PubMed2006

Risk-adapted BEACOPP regimen can reduce the cumulative dose of chemotherapy for standard and high-risk Hodgkin lymphoma with no impairment of outcome.

Therapy of Hodgkin disease (HD) is designed to prolong progression-free survival and minimize toxicity. The best regimen to achieve this has not yet been defined. A total of 108 patients with newly diagnosed HD and adverse prognostic factors were prospectively studied between 1999 and 2004. They were assigned to therapy according to defined risk stratification. Patients were defined depending on the International Prognostic Score (IPS). Those with IPS of 3 or higher received 2 cycles of escalated therapy, including bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP [EB]). All others received 2 cycles of standard BEACOPP (SB). Subsequent therapy was prospectively assigned following 2 cycles according to results of early interim 67Ga or positron emission tomography/computed tomography (PET/CT). Following a positive interim scan, 4 cycles of EB were administered, whereas 4 cycles of SB were given to patients with a negative scan. The complete remission rate, the 5-year event-free survival (EFS), and overall survival (OS) rates were 97%, 85% and 90%, respectively. Relapse or progression occurred in 27% of patients with interim positive PET/CT versus 2.3% of negative scans (P<.02). Early interim fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT is a useful tool for adjustment of chemotherapy on an individual basis. Similar EFS and OS rates were observed for patients in both risk groups.

Adult↗
PubMed2006

FDG-PET and CT patterns of bone metastases and their relationship to previously administered anti-cancer therapy.

PURPOSE: To assess (18)F-fluorodeoxyglucose (FDG) uptake in bone metastases in patients with and without previous treatment, and compare positive positron emission tomography (PET) with osteolytic or osteoblastic changes on computed tomography (CT). METHODS: One hundred and thirty-one FDG-PET/CT studies were reviewed for bone metastases. A total of 294 lesions were found in 76 patients, 81 in untreated patients and 213 in previously treated patients. PET was assessed for abnormal FDG uptake localised by PET/CT to the skeleton. CT was evaluated for bone metastases and for blastic or lytic pattern. The relationship between the presence and pattern of bone metastases on PET and CT, and prior treatment was statistically analysed using the chi-square test. RESULTS: PET identified 174 (59%) metastases, while CT detected 280 (95%). FDG-avid metastases included 74/81 (91%) untreated and 100/213 (47%) treated lesions (p<0.001). On CT there were 76/81 (94%) untreated and 204/213 (96%) treated metastases (p NS). In untreated patients, 85% of lesions were seen on both PET and CT (26 blastic, 43 lytic). In treated patients, 53% of lesions were seen only on CT (95 blastic, 18 lytic). Of the osteoblastic metastases, 65/174 (37%) were PET positive and 98/120 (82%), PET negative (p<0.001). CONCLUSION: The results of the present study indicate that when imaging bone metastases, prior treatment can alter the relationship between PET and CT findings. Most untreated bone metastases are PET positive and lytic on CT, while in previously treated patients most lesions are PET negative and blastic on CT. PET and CT therefore appear to be complementary in the assessment of bone metastases.

Adult↗
PubMed2006

Technetium-99m-MIBI SPECT/CT in primary hyperparathyroidism.

The novel trend toward focused parathyroidectomy requires precise preoperative localization of the parathyroid adenoma in patients with primary hyperparathyroidism (PHPT). The present study evaluated the impact of hybrid single photon emission computed tomography/computed tomography (SPECT/CT), using 99mTc-sestamibi (MIBI), on the surgical management of these patients. In a retrospective study of 36 patients with PHPT, SPECT/CT was undertaken when planar 99mTc-MIBI scintigraphy was negative or when an ill-defined focus in the neck or an ectopic site on planar views was visualized. Imaging data were compared with intraoperative findings, and the incremental value of SPECT/CT to lesion localization and surgical procedure was assessed. Three patients with both negative planar and SPECT/CT studies subsequently underwent bilateral neck exploration, with multiglandular hyperplasia diagnosed in two patients and a parathyroid adenoma in one. Of 33 patients with a positive MIBI study, parathyroid adenoma was confined to the neck in 23 patients and to the lower neck-mediastinum in 10. SPECT/CT facilitated the surgical exploration of all 10 ectopic parathyroid adenomas and 4 of 23 cervical parathyroid adenomas, the latter four either at reexploration or in patients with nonvisualization of the thyroid after thyroidectomy. SPECT/CT contributed to the localization of parathyroid adenomas in patients with PHPT and to planning the surgical exploration in 14 of 36 (39%) patients, predominantly those with ectopic parathyroid adenomas or who had distorted neck anatomy.

Adenoma↗
PubMed2006

Fluorodeoxyglucose-positron emission tomography/computed tomography imaging in patients with carcinoma of the larynx: diagnostic accuracy and impact on clinical management.

OBJECTIVES: The objectives of this study were to assess the value of F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with carcinoma of the larynx as compared with PET and CT alone and to assess the impact of PET/CT on further clinical management. STUDY DESIGN: This was a prospective, nonrandomized study. MATERIALS AND METHODS: Forty-two patients with laryngeal cancer had 51 PET/CT examinations. There were 34 men and eight women, aged 39 to 80 years. All studies were interpreted prospectively with knowledge of the clinical history and results of previous imaging tests. The performance of different imaging modalities was compared on both a study- and lesion-based analysis for sensitivity, specificity, positive (PPV) and negative predictive value (NPV), and accuracy. Changes in patient care resulting from the PET/CT studies were recorded. RESULTS: The study analysis showed that PET/CT had a sensitivity of 92%, specificity 96%, PPV 96%, NPV 92%, and accuracy of 94% as compared with 92%, 73%, 76%, 91%, and 82% for PET, and 88%, 8%, 48%, 40%, and 51% for CT, respectively. There were 112 suspicious sites evaluated in the 51 studies. PET/CT altered management in 25 patients (59%) by sparing previously planned diagnostic procedures (n=13), by changing the planned therapeutic approach (n=9), and by guiding a biopsy to a metabolically active laryngeal area (n=3). CONCLUSIONS: The performance of PET/CT is better than standalone PET or CT in patients with cancer of the larynx. PET/CT had a major impact on management of 59% of patients.

Adult↗
PubMed2006

Super-resolution in PET imaging.

This paper demonstrates a super-resolution method for improving the resolution in clinical positron emission tomography (PET) scanners. Super-resolution images were obtained by combining four data sets with spatial shifts between consecutive acquisitions and applying an iterative algorithm. Super-resolution attenuation corrected PET scans of a phantom were obtained using the two-dimensional and three-dimensional (3-D) acquisition modes of a clinical PET/computed tomography (CT) scanner (Discovery LS, GEMS). In a patient study, following a standard 18F-FDG PET/CT scan, a super-resolution scan around one small lesion was performed using axial shifts without increasing the patient radiation exposure. In the phantom study, smaller features (3 mm) could be resolved axially with the super-resolution method than without (6 mm). The super-resolution images had better resolution than the original images and provided higher contrast ratios in coronal images and in 3-D acquisition transaxial images. The coronal super-resolution images had superior resolution and contrast ratios compared to images reconstructed by merely interleaving the data to the proper axial location. In the patient study, super-resolution reconstructions displayed a more localized 18F-FDG uptake. A new approach for improving the resolution of PET images using a super-resolution method has been developed and experimentally confirmed, employing a clinical scanner. The improvement in axial resolution requires no changes in hardware.

Algorithms↗
PubMed2006

SPECT/CT using 67Ga and 111In-labeled leukocyte scintigraphy for diagnosis of infection.

UNLABELLED: The present study evaluated the role of SPECT/CT as an adjunct to (67)Ga (GS) or (111)In-labeled white blood cell (WBC) scintigraphy for diagnosis or localization of infection. METHODS: Eighty-two patients (56 male and 26 female; mean age, 62 y) assessed for known or suspected infectious processes underwent 88 SPECT/CT studies. Forty-seven patients underwent GS SPECT/CT (13 with fever of unknown origin, 21 with suspected osteomyelitis, and 13 with suspected soft-tissue infection), and 35 patients underwent WBC SPECT/CT (24 with suspected vascular graft infection, and 11 with suspected osteomyelitis). Ninety-eight suggestive sites were identified (52 on GS and 46 on WBC). Additional information provided by SPECT/CT for diagnosis or localization of infection, as compared with planar and SPECT scintigraphy, was recorded. The SPECT/CT contribution was analyzed on a patient and site basis and was compared for the 2 tracers and clinical indications. RESULTS: SPECT/CT provided additional information for infection diagnosis and localization in 39 (48%) of 82 patients and in 47 (48%) of 98 sites. SPECT/CT defined the extent of infection in 35 patients (43%) in 43 sites (44%) and excluded infection in 4 suggestive sites defined as physiologic bowel uptake on GS. SPECT/CT was incorrect in 2 suggestive sites (1 GS and 1 WBC). The contribution of SPECT/CT was significantly higher for WBC than for GS (P < 0.05)--in 63% versus 36% of patients, respectively, and in 61% versus 36% of sites, respectively. CONCLUSION: SPECT/CT made an incremental contribution to GS and WBC in 48% of patients with suspected infections, by improving diagnosis, localization, and definition of extent of disease. SPECT/CT has an important role mainly with highly specific, low-background infection-seeking tracers such as WBC.

Adolescent↗
PubMed2005

Fever due to aortitis.

We report a case of vasculitis with predominant aortic involvement. Vasculitis of large vessels has a limited number of tools for diagnosis and follow-up. A 78-year-old woman was referred to the internal medicine department with a 2-month history of fever of unknown origin (FUO), night sweats, weight loss and markedly elevated ESR and CRP. The results of an extended routine investigation found no infection, malignancy, hypersensitivity or autoimmune disorder. The patient did not suffer from claudication; systolic blood pressure difference between arms was 20 mm Hg. Temporal artery biopsies were negative. 2-18F-Fluorine-2-deoxy-D -glucose positron emission tomography (FDG PET) scan imaging demonstrated intense FDG uptake along the aorta and in the brachio-cephalic and carotid arteries consistent with arteritis. A high dose of corticosteroid therapy (1 mg/kg) was instituted with further tapering. The therapy was followed by complete resolution of the symptoms and pathological FDG uptake on repeated FDG PET. Second-line therapy was not added because of positive conversion of Mantaux test followed by rifampicin prophylaxis. FDG PET should be a part of the work-up of FUO when routine investigation fails to determine its etiology. FDG PET is useful both for diagnosis and assessment of response to therapy for large-vessel vasculitis.

Aged↗
PubMed2005

Paget's disease of bone or osteopetrosis?

We report a previously undescribed case of diffuse, scan-negative, and low active form of bone disease carrying clinical, x-ray, and biochemistry signs of Paget's disease of bone, which is analyzed in comparison with different forms of osteopetrosis.

Absorptiometry, Photon↗
PubMed2005

The additional value of PET/CT over PET in FDG imaging of oesophageal cancer.

PURPOSE: The aim of this study was to assess the value of combined PET/CT compared with PET reviewed side-by-side with CT, in patients with oesophageal cancer, before and after surgery. METHODS: Forty-one FDG PET/CT studies were performed in 32 patients with oesophageal cancer, before surgery (n = 18) or during follow-up after resection of the primary tumour (n = 23). One hundred and fifteen sites suspicious for malignancy were evaluated. PET/CT was prospectively compared with PET reviewed side-by-side with CT, for detection, accurate localisation and characterisation of malignant sites. PET/CT performance in different anatomical regions was compared before and after surgery. The impact of fused data on patient management was retrospectively assessed. RESULTS: PET/CT had an incremental value over PET for interpretation of 25 of 115 sites (22%), changing the initial characterisation of ten sites to either malignant (n = 1) or benign (n = 9), and defining the precise anatomical location of 15 sites. PET/CT provided better specificity and accuracy than PET for detecting sites of oesophageal cancer (81% and 90% vs 59% and 83% respectively, p < 0.01). Fusion was of special value for interpretation of cervical and abdomino-pelvic sites, for disease assessment in loco-regional lymph nodes before surgery and in regions of postoperative anatomical distortion. PET/CT had an impact on the further management of four patients (10%), by detecting nodal metastases that warranted disease upstaging (n = 2) and by excluding disease in sites of benign uptake after surgery (n = 2). CONCLUSION: PET/CT improves the accuracy of FDG imaging in oesophageal cancer and provides data of diagnostic and therapeutic significance for further patient management.

Adult↗
PubMed2005

Panaortitis: diagnosis via fluorodeoxyglucose positron emission tomography.

A 57-year-old woman was admitted with a 2-month history of low-grade fever, malaise, and weight loss. Physical examination findings were unremarkable except for a systolic murmur of a known mild aortic regurgitation. Laboratory tests revealed only mild leukocytosis and an elevated sedimentation rate. Serology tests for viral and bacterial pathogens, blood and urine cultures, and immunology tests had negative results. Total body computed tomography, transesophageal echocardiography, and biopsies of bone, liver, and temporal arteries were normal. Wide-spectrum antibiotics effected no change in the patient's illness. Low-dose steroids given for a suspected polymyalgia rheumatica caused only minimal and transient improvement. Re-evaluation showed no new findings. Fluorodeoxyglucose positron emission tomography (FDG-PET) was done and showed an abnormally increased uptake along the aortic arch, the descending aorta, and bilaterally in the subclavian and carotid arteries, compatible with arteritis. High-dose steroids and later methotrexate were given and caused obvious improvement, with complete resolution of symptoms. We conclude that FDG-PET should be a part of the usual work-up of fever of unknown origin, especially in cases in which routine investigation reveals no cause.

Aortitis↗
PubMed2005

The diabetic foot: initial experience with 18F-FDG PET/CT.

UNLABELLED: Osteomyelitis complicates up to one third of diabetic foot infections, is often due to direct contamination from a soft-tissue lesion, and represents a clinical challenge. Early diagnosis is important since antibiotic therapy can be curative and may prevent amputation. The present study assessed the role of PET/CT using 18F-FDG for the diagnosis of diabetic foot osteomyelitis. METHODS: Fourteen diabetic patients (10 men and 4 women; age range, 29-70 y) with 18 clinically suspected sites of infection underwent PET/CT after the injection of 185-370 MBq of 18F-FDG for suspected osteomyelitis complicating diabetic foot disease. PET, CT, and hybrid images were independently evaluated for the diagnosis and localization of an infectious process. Additional data provided by PET/CT for localization of infection in the bone or soft tissues were recorded. The final diagnosis was based on histopathologic findings and bacteriologic assays obtained at surgery or at clinical and imaging follow-up. RESULTS: PET detected 14 foci of increased 18F-FDG uptake suspected as infection in 10 patients. PET/CT correctly localized 8 foci in 4 patients to bone, indicating osteomyelitis. PET/CT correctly excluded osteomyelitis in 5 foci in 5 patients, with the abnormal 18F-FDG uptake limited to infected soft tissues only. One site of mildly increased focal 18F-FDG uptake was localized by PET/CT to diabetic osteoarthropathy changes demonstrated on CT. Four patients showed no abnormally increased 18F-FDG uptake and no further evidence of an infectious process on clinical and imaging follow-up. CONCLUSION: 18F-FDG PET can be used for diagnosis of diabetes-related infection. The precise anatomic localization of increased 18F-FDG uptake provided by PET/CT enables accurate differentiation between osteomyelitis and soft-tissue infection.

Adult↗
PubMed2005

PET/CT detection of unexpected gastrointestinal foci of 18F-FDG uptake: incidence, localization patterns, and clinical significance.

UNLABELLED: Precise PET/CT localization of focal (18)F-FDG uptake in the gastrointestinal tract (GIT) may exclude malignancy in sites of physiologic activity but may also induce false-negative reports for malignant or premalignant lesions. The purpose of the present study was to retrospectively evaluate the nature and significance of unexpected focal (18)F-FDG uptake localized by PET/CT within the GIT. METHODS: The files of 4,390 patients referred for (18)F-FDG PET/CT were retrospectively reviewed. The incidence of studies showing unexpected focal uptake of (18)F-FDG localized by PET/CT to the GIT was determined. The position of these foci along the GIT and their intensity were recorded. The etiology of the findings was confirmed histologically or by long-term follow-up. RESULTS: Unexpected focal (18)F-FDG uptake in the GIT was found in 58 patients (1.3%). Follow-up data were available for 34 of these patients, including 4 with sites in the stomach, 2 in the small bowel, and 28 in the colon. GIT-related disease was confirmed in 24 patients (71%). There were 11 malignant tumors, 9 premalignant lesions, and 4 benign processes including 2 benign polyps, 1 case of active gastritis, and 1 abscess of the sigmoid. Ten patients (29%) had no further evidence of GIT abnormality, and the suggestive sites were considered to be physiologic uptake. Maximal standardized uptake value was 17.3 +/- 10.2 in malignant lesions, 14.0 +/- 10.5 in premalignant lesions, 18.0 +/- 12.1 in benign lesions, and 11.1 +/- 7.4 in foci of physiologic (18)F-FDG uptake in the GIT, with no statistically significant difference among the 4 subgroups. CONCLUSION: Incidental focal (18)F-FDG uptake localized by PET/CT within the GIT is of clinical significance in most patients. These findings should be followed up with appropriate invasive procedures guided by hybrid imaging results.

Adult↗
PubMed2004

Non-malignant FDG uptake in infradiaphragmatic adipose tissue: a new site of physiological tracer biodistribution characterised by PET/CT.

The purpose of this study was to characterise a benign pattern of infradiaphragmatic 18F-fluorodeoxyglucose (FDG) uptake in cancer patients using PET/CT. Infradiaphragmatic foci of FDG uptake, localised by PET/CT in regions of normal fat tissues, were demonstrated, in conjunction with fatty uptake in the neck and shoulders, in 9 of 1,241 (0.7%) patients. The imaging and clinical characteristics of this pattern and its possible clinical significance were assessed. PET/CT precisely localised infradiaphragmatic fat uptake (IDFU) within normal retroperitoneal fatty tissue of the perirenal space (nine patients) and in the paracolic or parahepatic space (four patients). Perirenal uptake was bilateral in five patients and focal in six. Paracolic and parahepatic uptake was bilateral in three patients and linear in all four patients. There was no evidence of malignancy at any of the sites during a follow-up period of 9-21 months. IDFU was significantly more prevalent in young patients assessed for monitoring response to therapy, and was always associated with the benign supradiaphragmatic uptake pattern, although its prevalence was significantly lower. There were no significant differences between the clinical characteristics of these two patterns of benign fatty FDG uptake. It is concluded that PET/CT allows for precise identification of increased FDG uptake in abdominal fatty tissue and further exclusion of disease at such sites. This benign uptake may represent increased glucose consumption in activated brown adipose tissue, similar to the mechanism suggested for supradiaphragmatic uptake. Recognition of this benign IDFU pattern is important for correct interpretation of abdominal PET findings in cancer patients.

Abdominal Neoplasms↗