Integrated contrast-enhanced diagnostic whole-body PET/CT as a first-line restaging modality in patients with suspected metastatic recurrence of breast cancer

Objective(s)

Only few information exist about the diagnostic accuracy of PET/CT for restaging patients with metastatic recurrence of breast carcinoma. Therefore, our study hypothesis was to perform diagnostic contrast enhanced CT (ce-CT) and FDG-PET in a one-step investigation, to prove sensitivity of each modality and to determine whether diagnostic PET/CT adds information over PET or contrast enhanced CT alone for restaging of patients with suspected recurrence of breast cancer.

Methods

Fifty-two patients with suspected recurrence of breast cancer were included in our study. All of them were free of metastasis after the first line therapy. Indications for restaging were: Elevated tumor markers n = 32, clinical deterioration n = 16 and/or suspicious findings on other imaging studies n = 48. Integrated PET/CT was performed using contrast-enhanced diagnostic CT for attenuation correction.

Results

PET was correct in 44/52 patients (85%), ce-CT in 38/52 patients (73%) and PET/CT in 50/52 patients (96%). Sensitivity and specificity of lesion detection of PET, CT and PET/CT were 84%, 66% and 93%, and 100%, 92%, and 100%, respectively.

Discussion

PET/CT can improve staging and alter therapeutic options in patients suspected to have breast cancer recurrence and distant metastatic disease, primarily by demonstrating local or distant nodal involvement occult at other imaging studies. The added value of FDG-PET/CT over other diagnostic modalities is mainly expressed by the fact that a noninvasive whole-body evaluation is possible in a single examination.     

Breast MRI and<Superscript>18</Superscript>F FDG PET/CT in the management of breast cancer

GOALS: 18F FDG PET/CT is used for diagnosis, staging and establishing the response to therapy in various malignancies, including breast cancer (BC). Dedicated breast MRI (BMRI) is gaining a role in the management of BC patients (pts), demonstrating high sensitivity and specificity for detection of small lesions. We were therefore prompted to review our experience with PET and BMRI in BC. METHODS: This is a retrospective study of 21 women with BC, 30-76 years old, who had BMRI and whole-body FDG PET/CT at our institution from Jun 2002 to May 2005. A total of 6 patients (group A) had BMRI and PET/CT in the preoperative period and 15 patients (group B) had BMRI and PET/CT after surgery. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed. RESULTS: For group A, BMRI identified breast lesions in 4 patients, while PET/CT was able to identify breast lesions in 5 patients. All these were proven to be malignancy on pathology examination. In group B, BMRI detected recurrent breast lesions in 8 patients, with 88.9% sensitivity and 83.3% specificity. In the same patient population, PET/CT was 33.3% sensitive and 91.7% specific. As a whole body examination, PET/CT revealed metastatic disease in 6 patients (100% sensitive and 90% specific). Overall, sensitivities and specificities for breast disease detection were 85.7% and 85.7% for BMRI, and 75% and 92.3% for 18F FDG PET/ CT. CONCLUSIONS: As expected, BMRI is more sensitive than PET/CT in the detection of breast lesions. However, PET/CT as a whole-body examination changed the management of disease by detection of distant lesions in 6 of the 21 patients. Our study suggests that 18F FDG PET/CT and BMRI should be considered as complimentary imaging tools in the pre- and postoperative work-up of patients diagnosed with breast cancer.     

False-Positive FDG PET Uptake−the Role of PET/CT

Positron emission tomography (PET) is a powerful molecular imaging technique for the human body-imaging applications currently available. As altered glucose metabolism is characteristic for many malignancies, FDG-PET is mostly used in oncology for staging and therapy control. Although PET is a sensitive tool for detecting malignancy, FDG uptake is not tumor specific. It can also be seen in healthy tissue or in benign disease as inflammation or posttraumatic repair and could be mistaken for cancer. The experienced nuclear medicine physician mostly manages to differentiate malignant from non-malignant FDG uptake, but some findings may remain ambiguous. In these cases, the difficulties in differentiating physiologic variants or benign causes of FDG uptake from tumor tissue can often be overcome by combined PET and CT (PET/CT) as anatomic information is added to the metabolic data. Thus, PET/CT improves the diagnostic accuracy compared to PET alone and helps to avoid unnecessary surgery/therapy. However, PET/CT involves other sources of artifacts that may occur when using CT for attenuation correction of PET or by patient motion caused by respiration or bowel movements.     

(18)F-FDG PET versus (18)F-FDG PET/CT for adrenal gland lesion characterization: a comparison of diagnostic efficacy in lung cancer patients.

OBJECTIVE: The aim of this study was to assess the diagnostic efficacy of integrated PET/CT using fluorodeoxyglucose (FDG) for the differentiation of benign and metastatic adrenal gland lesions in patients with lung cancer and to compare the diagnostic efficacy with the use of PET alone. MATERIALS AND METHODS: Sixty-one adrenal lesions (size range, 5-104 mm; mean size, 16 mm) were evaluated retrospectively in 42 lung cancer patients. Both PET images alone and integrated PET/CT images were assessed, respectively, at two-month intervals. PET findings were interpreted as positive if the FDG uptake of adrenal lesions was greater than or equal to that of the liver, and the PET/CT findings were interpreted as positive if an adrenal lesion show attenuation > 10 HU and showed increased FDG uptake. Final diagnoses of adrenal gland lesions were made at clinical follow-up (n = 52) or by a biopsy (n = 9) when available. The diagnostic accuracies of PET and PET/CT for the characterization of adrenal lesions were compared using the McNemar test. RESULTS: Thirty-five (57%) of the 61 adrenal lesions were metastatic and the remaining 26 lesions were benign. For the depiction of adrenal gland metastasis, the sensitivity, specificity, and accuracy of PET were 74%, 73%, and 74%, respectively, whereas those of integrated PET/CT were 80%, 89%, and 84%, respectively (p values; 0.5, 0.125, and 0.031, respectively). CONCLUSION: The use of integrated PET/CT is more accurate than the use of PET alone for differentiating benign and metastatic adrenal gland lesions in lung cancer patients.     

Clinical value of FDG PET or PET/CT in urinary bladder cancer: a systemic review and meta-analysis

Aim

The purpose of the current study was to conduct a systemic review and meta-analysis of the published literature to evaluate the diagnostic accuracy of FDG PET or PET/CT in urinary bladder cancer.

Materials and methods

The authors conducted a systematic MEDLINE search of articles published between January 2000 and December 2010. Two reviewers independently assessed the methodological quality of each study. We conducted a meta-analysis of pooled sensitivity and specificity in detecting primary and metastatic lesions of bladder cancer.

Results

Six studies met the inclusion criteria. The pooled sensitivity and specificity of PET/CT for primary lesion detection of bladder cancer were 0.90 (95% CI: 0.70–0.99) and 1.00 (95% CI: 0.74–1.00), respectively. The pooled sensitivity and specificity of FDG PET or PET/CT for staging or restaging (metastatic lesions) of bladder cancer were 0.82 (95% CI: 0.72–0.89) and 0.89 (95% CI: 0.81–0.95), respectively.

Conclusion

The diagnostic accuracy of FDG PET or PET/CT is good in metastatic lesions of urinary bladder cancer. Due to the small number of patients and limited number of studies analyzed, the diagnostic capability of FDG PET or PET/CT in detection of primary bladder wall lesions could not be assessed.     

Comparative study of FDG PET/CT and conventional imaging in the staging of rhabdomyosarcoma

Objective  The current study was conducted to compare the diagnostic accuracy between ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT), and conventional imaging (CI) for the staging and re-staging of patients with rhabdomyosarcomas. Methods  Thirty-five patients who underwent FDG PET/CT prior to treatment were evaluated retrospectively. CI methods consisted of ^99mTc-hydroxymethylene diphosphonate bone scintigraphy, chest radiograph, whole body CT, and magnetic resonance imaging of the primary site. The images were reviewed and two boardcertified radiologists reached a diagnostic consensus. Tumor stage was confirmed by histological examination and/or follow-up examinations. Results  Interpretation on the basis of FDG PET/CT, and CI, diagnostic accuracies of the T and N stages were similar. Using FDG PET/CT, the M stage was correctly assigned in 31 patients (89%), whereas the accuracy of CI in M stage was 63%. TNM stage was correctly assessed with FDG PET/CT in 30 of 35 patients (86%) and with CI in 19 of 35 patients (54%). The overall TNM staging and M staging accuracies of FDG PET/CT were significantly higher than that of CI (P < 0.01). Conclusions  FDG PET/CT is more accurate than CI regarding clinical staging and re-staging of patients with rhabdomyosarcomas.     

Whole-body FDG PET/CT is more accurate than conventional imaging for staging primary breast cancer patients

Purpose

This retrospective study aimed (1) to compare the diagnostic accuracy of whole-body FDG PET/CT for initial breast cancer staging with the accuracy of a conventional, multimodal imaging algorithm, and (2) to assess potential alteration in patient management based on the FDG PET/CT findings.

Methods

Patients with primary breast cancer (106 women, mean age 57?±?13?years) underwent whole-body FDG PET/CT and conventional imaging (X-ray mammography, MR mammography, chest plain radiography, bone scintigraphy and breast, axillary and liver ultrasonography). The diagnostic accuracies of FDG PET/CT and a conventional algorithm were compared. Diagnostic accuracy was assessed in terms of primary tumour detection rate, correct assessment of primary lesion focality, T stage and the detection rates for lymph node and distant metastases. Histopathology, imaging or clinical follow-up served as the standards of reference.

Results

FDG PET/CT was significantly more accurate for detecting axillary lymph node and distant metastases (p?=?0.0125 and p?Conclusion Full-dose, intravenous contrast-enhanced FDG PET/CT was more accurate than conventional imaging for initial breast cancer staging due to the higher detection rate of metastases and synchronous tumours, although the study had several limitations including a retrospective design, a possible selection bias and a relevant false-positive rate for the detection of axillary lymph node metastases. FDG PET/CT resulted in a change of treatment in a substantial proportion of patients.     

Integrated PET/CT as a first-line re-staging modality in patients with suspected recurrence of ovarian cancer

Purpose The aims of this study were to compare CT with PET/CT results in patients with suspected ovarian cancer recurrence and to assess the impact of the PET/CT findings on their clinical management. Methods Thirty-two consecutive patients with suspected ovarian cancer recurrence were retrospectively included in the study. Abdominal contrast-enhanced CT and PET/CT with [¹⁸F]FDG, in addition to conventional follow-up, were performed in all 32 patients. After the comparison between CT and PET/CT results, based on clinical reports, changes in the clinical management of patients (intermodality changes) due to PET/CT information were analysed. Results Twenty of the 32 patients were positive at CT (62.5%) versus 29 (90.6%) at PET/CT. Intermodality changes in management, i.e. use of a different treatment modality, after PET/CT examination were indicated in 14/32 (44%) patients. In particular, before PET/CT study, the planned management was as follows: wait-and-see in 7/32 (22%), further instrumental examinations in 4/32 (12%), chemotherapy in 10/32 (31%), diagnostic surgical treatment in 6/32 (19%) and surgical treatment in the remaining 5/32 (16%). After PET/CT study, wait-and-see was indicated in 1/32 (3%), further instrumental examinations in 7/32 (22%), chemotherapy in 16/32 (50%), diagnostic surgical treatment in 2/32 (6%) and surgical treatment in the remaining 6/32 (19%). Conclusion Integrated PET/CT could detect tumour relapse in a higher percentage of patients than could CT. A change in the clinical management was observed in 44% of cases when PET/CT information was added to conventional follow-up findings. G. Mangili and M. Picchio contributed equally to this work.     

The diagnostic value of PET/CT in recurrence and distant metastasis in breast cancer patients and impact on disease free survival

Aim of work

To detect the diagnostic value of PET/CT in breast cancer patients. We compared the performance of PET/CT with that of conventional imaging in detection of recurrence and distant metastasis and evaluated the impact PET/CT results have on disease free survival.

Materials and methods

We retrospectively studied 50 patients with breast cancer with clinical suspicion of recurrent or metastatic lesion and who underwent PET/CT and conventional imaging procedures. The imaging results were retrospectively compared with histopathology and clinical follow-up as a reference standard.

Results

PET/CT detected distant metastases with a sensitivity of 97% and a specificity of 93%. In contrast, the sensitivity and specificity of combined conventional imaging procedures were 75% and 73%, respectively, disease-free survival was significantly shorter in the 34 M1-PET/CT patients than in the 14 M0-PET/CT patients (log-rank P = 0.002) also PET/CT detected recurrence in 1 patient with equivocal mammographic findings.

Conclusion

In breast cancer, PET/CT is superior to conventional imaging procedures for detection of recurrence, distant metastases and PET/CT can be used to improve prediction of the clinical outcome of breast cancer patients.     

PET/CT for the staging and follow-up of patients with malignancies

Positron emission tomography (PET) and computed tomography (CT) complement each other's strengths in integrated PET/CT. PET is a highly sensitive modality to depict the whole-body distribution of positron-emitting biomarkers indicating tumour metabolic activity. However, conventional PET imaging is lacking detailed anatomical information to precisely localise pathologic findings. CT imaging can readily provide the required morphological data. Thus, integrated PET/CT represents an efficient tool for whole-body staging and functional assessment within one examination. Due to developments in system technology PET/CT devices are continually gaining spatial resolution and imaging speed. Whole-body imaging from the head to the upper thighs is accomplished in less than 20 min. Spatial resolution approaches 2–4 mm. Most PET/CT studies in oncology are performed with ¹⁸F-labelled fluoro-deoxy-d-glucose (FDG). FDG is a glucose analogue that is taken up and trapped within viable cells. An increased glycolytic activity is a characteristic in many types of cancers resulting in avid accumulation of FDG. These tumours excel as “hot spots” in FDG-PET/CT imaging. FDG-PET/CT proved to be of high diagnostic value in staging and restaging of different malignant diseases, such as colorectal cancer, lung cancer, breast cancer, head and neck cancer, malignant lymphomas, and many more. The standard whole-body coverage simplifies staging and speeds up decision processes to determine appropriate therapeutic strategies. Further development and implementation of new PET-tracers in clinical routine will continually increase the number of PET/CT indications. This promotes PET/CT as the imaging modality of choice for working-up of the most common tumour entities as well as some of the rare malignancies.     

Initial evaluation of <Superscript>18</Superscript>F-fluorothymidine (FLT) PET/CT scanning for primary pancreatic cancer

Purpose The aim of this study was to evaluate the potential of ¹⁸F-fluorothymidine (FLT) PET/CT for imaging pancreatic adenocarcinoma. Methods This was a pilot study of five patients (four males, one female) with newly diagnosed and previously untreated pancreatic adenocarcinoma. Patients underwent FLT PET/CT, ¹⁸F-fluorodeoxyglucose (FDG) PET/CT, and contrast-enhanced CT scanning before treatment. The presence of cancer was confirmed by histopathological analysis at the time of scanning in all five patients. The degree of FLT and FDG uptake at the primary tumor site was assessed using visual interpretation and semi-quantitative SUV analyses. Results The primary tumor size ranged from 2.5×2.8 cm to 3.5 × 7.0 cm. The SUV of FLT uptake within the primary tumor ranged from 2.1 to 3.1. Using visual interpretation, the primary cancer could be detected from background activity in two of five patients (40%) on FLT PET/CT. By comparison, FDG uptake was higher in each patient with a SUV range of 3.4 to 10.8, and the primary cancer could be detected from background in all five patients (100%). Conclusions In this pilot study of five patients with primary pancreatic adenocarcinoma, FLT PET/CT scanning showed poor lesion detectability and relatively low levels of radiotracer uptake in the primary tumor.     

Role of [<Superscript>18</Superscript>F]FDG PET/CT in the assessment of suspected recurrent ovarian cancer: correlation with clinical or histological findings

Purpose To evaluate the accuracy of integrated positron emission tomography (PET) and computed tomography (CT) for depiction of suspected recurrent ovarian carcinoma after treatment, with use of clinical or histological findings as the reference standard. Methods Seventy-seven women (median age, 51 years) with ovarian carcinoma treated with primary cytoreductive surgery followed by platinum-based combination chemotherapy were included, and [¹⁸F]fluorodeoxyglucose (FDG) PET/CT was performed for suspected recurrence. In all patients, imaging findings were compared with results of histological examination after surgical exploration or clinical follow-up to determine the diagnostic accuracy of PET/CT in the evaluation of disease status. Fisher’s exact test was used to measure the ability of PET/CT to predict recurrent lesions. Results Forty-five (58.4%) of the 77 patients had documented recurrence during surgical exploration or clinical follow-up, while 32 (41.6%) had no evidence of recurrent tumour. Of the 45 patients with recurrent disease, 27 (60%) were confirmed to have recurrence by surgical biopsy. A correlation was found between PET/CT and histological or clinical analyses (κ = 0.894). The overall sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PET/CT were 93.3%, 96.9%, 94.8%, 97.7% and 91.2%, respectively. PET/CT modified the diagnostic or treatment plan in 19 (24.7%) patients, by leading to the use of previously unplanned therapeutic procedures in 11 (57.9%) patients and the avoidance of previously planned diagnostic procedures in eight (42.1%) patients. Conclusion Integrated FDG PET/CT is a sensitive post-therapy surveillance modality for the detection of recurrent ovarian cancer; it aids decisions on treatment plans and may ultimately have a favourable impact on prognosis.     

Comparison of imaging with FDG PET/CT with other imaging modalities in myeloma

Objective To determine the usefulness of FDG PET/CT scanning in the management and staging of myeloma and to assess its strengths and limitations.Design FDG PET/CT scans and all other available imaging studies were reviewed retrospectively from 16 consecutive patients by two experienced musculoskeletal radiologists and two nuclear medicine physicians working in consensus.Patients The 16 patients had undergone a total of 19 FDG PET/CT scans. Radiographs were available in all cases, including 13 skeletal surveys; 25 CT scans (16 chest, three abdominal, four pelvic, one spine, one neck) and 22 MR imaging studies (17 spine, three pelvic, two extremity) also were reviewed. Patients’ records were examined for relevant clinical information. All focal areas of abnormal FDG uptake were correlated with the other imaging studies to determine clinical significance. FDG PET/CT scans also were reviewed to see if small lesions shown on the other imaging studies could be identified in retrospect.Results The 12 men and four women had an average age of 58 years (range 30–69 years). All 16 patients had an established diagnosis of multiple myeloma, with average duration of disease, from time of initial diagnosis to review, of 30 months (range 6 months to 11+ years). The FDG PET/CT scans revealed a total of 104 sites (90 in bone, 14 soft tissue) that were suspicious for neoplastic activity based on a standardized uptake value (SUV) greater than 2.5. Fifty-seven of these sites (55%) were new or previously undetected. The other imaging studies (X-ray, CT, MR) and clinical information confirmed the other 47 areas but also revealed 133 other small skeletal lesions. Six of these 133 additional lesions showed mild FDG uptake on re-review of the PET/CT scans. The FDG PET/CT findings led to management changes in 9/16 patients. MR imaging revealed five cases of diffuse bone involvement (four spine, one scapula) that were not evident by FDG PET/CT.Conclusion FDG PET/CT scans are useful for the management and staging of myeloma. However, if PET/CT were the sole imaging study done, it would miss many additional small lytic skeletal lesions and could miss diffuse spine involvement.     

Brown fat in breast cancer patients: analysis of serial 18F-FDG PET/CT scans

Purpose It has recently been suggested that FDG accumulation in the brown adipose tissue varies as a function of age, sex and outdoor temperature. The aim of this study was to assess changes in FDG uptake in brown fat in patients based on serial PET/CT scans and to compare our results with previous findings. Methods Early response to neoadjuvant chemotherapy in 33 female breast cancer patients was assessed by FDG PET. Five PET/CT scans were performed for each patient. PET/CT images were analysed retrospectively. PET scans were considered positive when diffuse, symmetrical, abnormal “USA” (uptake in supraclavicular area) fat was detected. Results A total of 163 PET images were analysed. Seventy-four PET scans (45%) revealed abnormal FDG uptake in the supraclavicular area. These foci were present on uncorrected and attenuation-corrected images. FDG uptake was identical on all five scans in only five patients. No significant relationship was found between abnormal FDG uptake and outdoor temperature, age or time interval between chemotherapy and PET. Abnormal FDG uptake in the neck seemed to predominantly occur in patients with a low body mass index (p<0.05). Most significant changes in the PET/CT scan results were observed during chemotherapy with docetaxel (p<0.05). When observed, bilateral uptake in the neck was more intense than background uptake (p<0.00001). Conclusion This study shows that FDG uptake in the neck varies as a function of time, that it is unrelated to age or outdoor temperature, and that bilateral uptake is generally intense.     

Is There Any Additional Benefit of Contrast-Enhanced CT as Part of Routine PET/CT Protocols for the Differentiation of Suspicious Incidental Gastrointestinal 2-Deoxy-18F-FDG Uptake?

Objective

Suspicious incidental gastrointestinal FDG uptake during positron-emission tomography/computed tomography (PET/CT) examinations can be caused by different diseases, including malignancies. However, differentiation with PET alone is difficult. The aim of this study was to investigate the potential of PET alone, contrast-enhanced CT (ceCT), and low-dose CT (ldCT) in routine PET/CT protocols for differentiation of incidental gastrointestinal lesions.

Materials and Methods

Sixty patients with incidental gastrointestinal lesions who underwent a routine PET/CT protocol with ldCT and ceCT were retrospectively analysed. The PET lesions were evaluated regarding their FDG uptake patterns and the standard uptake value. The anatomical correlates in both CT protocols were compared in regard to the correct lesion classification with the reference standard endoscopy.

Results

Sixty-two lesions were found in 60 patients (17 malignant, 10 premalignant, 5 benign, 13 inflammatory, 17 physiological). The differentiation of the FDG uptake patterns did not enable reliable lesion classification. The positive predictive value for pathology was 0.81 for ceCT in PET/CT and 0.70 for ldCT. Malignancies were detected in 100% of the patients by ceCT vs. 29.4% by ldCT. The false negative rate of ceCT for all pathologies was 31.1%, vs. 68.9% for ldCT. False positive results (17/62) could not be excluded sufficiently by either CT protocol.

Conclusion

PET/ceCT protocols provide additional benefit especially in detecting gastrointestinal malignancies as a cause of suspicious incidental gastrointestinal FDG uptake. However, since follow-up endoscopy cannot be forgone due to the considerable false negative rate even with ceCT, the addition of ceCT to a routine PET/ldCT protocol cannot be recommended for this purpose.     

Bone metastasis in patients with non-small cell lung cancer: The diagnostic role of F-18 FDG PET/CT

Purpose

To evaluate the performance of F-18 FDG PET/CT in the detection of bone metastasis in non-small cell lung cancer (NSCLC) patients.

Materials and methods

Three hundred and sixty-two consecutive NSCLC patients who underwent F-18 FDG PET/CT scanning were retrospectively analyzed. Each image of PET/CT, combined CT, and PET was performed at 10 separate areas and interpreted blindly and separately. The sensitivity, specificity and accuracy of F-18 FDG PET/CT, combined CT and F-18 FDG PET were calculated and the results were statistically analyzed.

Results

Bone metastasis was confirmed in 82 patients with 331 positive segments based on the image findings and clinical follow-up. On patient-based analysis, the sensitivity of F-18 FDG PET/CT (93.9%) was significantly higher than those of combined CT (74.4%) and F-18 FDG PET (84.1%), respectively (p < 0.05). The overall specificity and accuracy of combined CT, F-18 FDG PET, and F-18 FDG PET/CT were 90.7%, 93.2%, 98.9% and 87.0%, 91.2%, and 97.8%, respectively (compared with PET/CT, p < 0.05). On segment-based analysis, the sensitivity of the three modalities were 79.5%, 94.3%, and 98.8%, respectively (compared with PET/CT, p < 0.05). The overall specificity and accuracy of the three modalities were 87.9%, 89.2%, 98.6% and 84.5%, 91.2%, 98.7%, respectively (compared with PET/CT, p < 0.05).

Conclusion

F-18 FDG PET/CT is superior to F-18 FDG PET or combined CT in detecting bone metastasis of NSCLC patients because of the complementation of CT and PET. It is worth noting that the added value of F-18 FDG PET/CT may beneficially impact the clinical management of NSCLC.     

PET/CT imaging: The incremental value of assessing the glucose metabolic phenotype and the structure of cancers in a single examination

PET/CT with the glucose analogue FDG is emerging as the most important diagnostic imaging tool in oncology. More than 2000 PET/CT scanners are operational worldwide and its unique role for diagnosing, staging, restaging and therapeutic monitoring in cancer is undisputed. Studies conducted in thousands of cancer patients have clearly indicated that the combination of molecular PET with anatomical CT imaging provides incremental diagnostic value over PET or CT alone. State of the art imaging protocols combine fully diagnostic CT scans with quality whole body PET surveys. The current review briefly describes the biological alterations of cancer cells that result in their switch to a strongly glycolytic phenotype. Different whole body imaging protocols are discussed. We summarize the evidence for the incremental value of PET/CT over CT and PET alone using imaging of sarcoma as an example. Following this section we discuss the performance of FDG-PET/CT imaging for staging, restaging and monitoring of head and neck cancer, solitary lung nodules and lung cancer, breast cancer, colorectal cancer, lymphoma and unknown primary tumors. Finally, the recently emerging evidence of a substantial impact of PET/CT imaging on patient management is presented.     

The role of PET/CT for evaluating breast cancer.

Positron emission tomography combined with computed tomography (PET/CT) has been receiving increasing attention during the recent years for making the diagnosis, for determining the staging and for the follow-up of various malignancies. The PET/CT findings of 58 breast cancer patients (age range: 34-79 years old, mean age: 50 years) were retrospectively compared with the PET or CT scans alone. PET/CT was found to be better than PET or CT alone for detecting small tumors or multiple metastases, for accurately localizing lymph node metastasis and for monitoring the response to chemotherapy in breast cancer patients.     

Head and neck squamous cell carcinoma (HNSCC) – detection of synchronous primaries with <Superscript>18</Superscript>F-FDG-PET/CT

Purpose  The aim of the study was to evaluate ¹⁸F-FDG-PET/CT for the detection of synchronous primaries at initial staging of patients with head and neck squamous cell carcinoma (HNSCC). Methods  FDG-PET/CT images acquired between March 2001 and October 2007 in 589 consecutive patients (147 women, 442 men; mean age 61.5 years, age range 32–97 years) with proven HNSCC were reviewed for the presence of synchronous primaries. Cytology, histology and/or clinical and imaging follow-up served as reference standard. Results  FDG-PET/CT showed 69 suspected synchronous primaries in 62 patients of which 56 were finally confirmed in 44 patients. Of the 56 second cancers, 46 (82%) were found in the aerodigestive tract in the following locations: lung (26, 46%), head and neck (15, 17%), oesophagus (5, 9%). Ten second cancers (18%) were located outside the aerodigestive tract (colon, five; stomach, lymphoma, breast, thymus and kidney, one each). Six patients had three synchronous primaries and three patients had four synchronous cancers. Nine synchronous cancers were not detected by PET/CT (four head and neck, two lung, two oesophageal, one gastric). False-positive PET/CT findings were mainly related to benign FDG uptake in the intestine due to benign or precancerous polyps or physiological FDG uptake in other head and neck regions. Overall the prevalence of synchronous second primaries according to the reference standard was 9.5%, of which 84% were detected with FDG-PET/CT. In 80% of the patients, therapy was changed because of the detection of a synchronous primary. Conclusion  FDG-PET/CT detects a considerable number of synchronous primaries (8.0% prevalence) at initial staging of patients with HNSCC. Synchronous cancers were predominantly located in the aerodigestive tract, primarily in the lung, head and neck and oesophagus. Detection of second primaries has an important impact on therapy. PET/CT should be performed before panendoscopy.     

Accuracy of 18F-FDG PET/CT in detection and restaging of recurrent ovarian cancer

Purpose

To estimate the accuracy of 18FDG PET/CT in detection of recurrent cancer ovary and to describe the localization of metastases for restaging.