PET-CT in recurrent ovarian cancer: initial observations

Imaging of Peritoneal Metastases in Ovarian Cancer Using MDCT, MRI, and FDG PET/CT: A Systematic Review and Meta-Analysis

This review aims to compare the diagnostic performance of multidetector CT (MDCT), MRI, including diffusion-weighted imaging, and FDG PET/CT in the detection of peritoneal metastases (PMs) in ovarian cancer (OC). A comprehensive search was performed for articles published from 2000 to February 2023. The inclusion criteria were the following: diagnosis/suspicion of PMs in patients with ovarian/fallopian/primary peritoneal cancer; initial staging or suspicion of recurrence; MDCT, MRI and/or FDG PET/CT performed for the detection of PMs; population of at least 10 patients; surgical results, histopathologic analysis, and/or radiologic follow-up, used as reference standard; and per-patient and per-region data and data for calculating sensitivity and specificity reported. In total, 33 studies were assessed, including 487 women with OC and PMs. On a per-patient basis, MRI (p = 0.03) and FDG PET/CT (p < 0.01) had higher sensitivity compared to MDCT. MRI and PET/CT had comparable sensitivities (p = 0.84). On a per-lesion analysis, no differences in sensitivity estimates were noted between MDCT and MRI (p = 0.25), MDCT and FDG PET/CT (p = 0.68), and MRI and FDG PET/CT (p = 0.35). Based on our results, FDG PET/CT and MRI are the preferred imaging modalities for the detection of PMs in OC. However, the value of FDG PET/CT and MRI compared to MDCT needs to be determined. Future research to address the limitations of the existing studies and the need for standardization and to explore the cost-effectiveness of the three imaging modalities is required.

Role of Computed Tomography in the Evaluation of Peritoneal Carcinomatosis

Peritoneal carcinomatosis (PC) refers to metastatic spread of tumor into the peritoneal cavity. Earlier, PC was thought to be associated with grave clinical outcome. However, various advances in treatment options including cytoreductive surgery and heated intraperitoneal chemotherapy or early post-operative chemotherapy can prolong survival of patients with peritoneal carcinomatosis. These treatment options are associated with high morbidity and mortality. The purpose of this article is to acquaint the radiologist about various appearances of peritoneal carcinomatosis in order to help clinicians in selecting candidates for surgery and avoid unnecessary potentially debilitating surgeries in patients with unresectable PC.

Breast Metastasis of Primary Peritoneal Carcinoma Demonstrated on FDG PET/CT

ABSTRACT

Primary serous peritoneal carcinomas (PSPCs) are rare, and dissemination other than intraperitoneal implantation is even rarer. Breast is an extremely unusual location of metastasis for PSPC. The distinction of breast metastasis of PSPC from primary breast cancer is crucial because the treatment and the prognosis are entirely different. Here we present a case of breast and axillary lymph node metastases from PSPC that were identified on staging FGD PET/CT.

The Role of 18F-FDG PET/CT in Detecting Ovarian Cancer Recurrence in Patients with Elevated CA-125 Levels

Objectives:

To investigate the role of ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) in detection of recurrence in ovarian cancer patients with increased CA-125 levels.

Methods:

Fifty-two patients (30-80 years old, mean: 58.5±10.6 years) who had been histopathologically diagnosed with ovarian cancer, underwent ¹⁸F-FDG PET/CT imaging for re-staging due to elevation of CA-125 levels were included in this retrospective study. ¹⁸F-FDG PET/CT findings were compared with histopathological, radiological and clinical follow-up results.

Results:

CA-125 levels ranged between 35.2-2740 U/mL (N: 0-35 U/mL). Recurrent disease was detected in 45 of 52 patients on PET/CT imaging. There were three false negative and one false positive result. In addition to abdominal and pelvic lesions, 14 distant metastatic lesions (brain, lung, liver and bone metastasis) were identified correctly on PET/CT imaging. Sensitivity, specificity, positive and negative predictive value and accuracy of ¹⁸F-FDG PET/CT were calculated as 94%, 75%, 98%, 50% and 96%, respectively.

Conclusion:

¹⁸F-FDG PET/CT is a useful imaging method that can be used in detection of ovarian cancer recurrence in patients with elevated CA-125 levels. Since this modality offers whole body imaging, distant metastases could be detected in addition to abdominal and pelvic lesions thus contributing to patient management.

Appearance of Adrenal Myelolipomas on 2-deoxy-2-(18F) fluoro-D-glucose Positron Emission Tomography-Computed Tomography

With the widespread use of 2-deoxy-2-(¹⁸F) fluoro-D-glucose positron emission tomography-computed tomography (FDG PET/CT) in oncologic imaging, it has become increasingly important for physicians who interpret FDG PET/CT scans to confidently recognize the spectrum of incidentally encountered benign and malignant findings. The adrenal glands represent an interesting nexus of multiple rare and common benign intrinsic tumors as well as metastases from a variety of primary malignancies. Given the breadth of adrenal gland pathology, careful description of the FDG PET/CT appearance of these pathologies is of value to help reduce misinterpretation. In this manuscript, we retrospectively and systematically review the FDG PET/CT imaging characteristics of benign adrenal myelolipomas in a small consecutive patient series. The myelolipomas in this series demonstrated differing degrees of macroscopic fat visible on CT, with generally mild FDG uptake fusing to the nonfatty portions of the lesions. At imaging follow-up, all of the myelolipomas in this series remained unchanged in appearance, helping to confirm their benign nature. The typical appearance of a myelolipoma on FDG PET/CT is a fat-containing adrenal mass with low-level FDG uptake in the nonfatty aspects of the mass, and such a lesion requires no further imaging workup.

Role of PET-CT Scan in Gynaeconcology

THE PURPOSE OF THIS STUDY

This study was undertaken to evaluate the role of positron emission tomography-CT (PET-CT) in diagnosis and management of gynecological malignancies in primary and recurrent settings and also to investigate its role in inappropriately treated patients, for pretreatment evaluation (staging) to help in proper therapeutic management.

METHOD

This is a retrospective study of 56 patients of gynecological malignancy registered in Gujarat Cancer Research Institute from June 2011 to December 2013.

RESULTS

Out of 56 cases where PET was done, the results were as follows: carcinoma cervix-23, carcinoma ovary-20, carcinoma endometrium-9, carcinoma vulva-1, carcinoma vagina-2, and GTN-1. PET scan was negative in 37 % of patients where CT scan was suspicious, which changed the therapeutic modality and prevented further unnecessary interventions. In cases where clinical suspicion of recurrence was high based on rising tumor marker and CT scan was negative, subsequent PET-CT was able to pick up malignancy in 75 % cases. Eleven patients (25 %) with suspected recurrence with inconclusive CT scan and negative PET-CT scan were kept on follow-up, thus reducing further morbidity and cost.

CONCLUSION

Addition of PET-CT, a noninvasive method to the oncologist's imaging armamentarium may ultimately improve both outcomes and costs by altering management strategies in primary and recurrent settings. The potential use of PET-CT appears promising in several decision-making steps in the management of patients with gynecological malignancy. It defines the extent of metastatic disease which enables the clinician to decide regarding salvageable surgical intervention or palliative measures.

Positron emission tomography: clinical applications in oncology. Part 1

Positron emission tomography is a functional diagnostic imaging technique, which can accurately measure in vivo distribution of a radiopharmaceutical with high resolution. The ability of positron emission tomography to study various biologic processes opens up new possibilities for both research and day-to-day clinical use. Positron emission tomography has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality becoming part of armamentarium for the medical profession. The most widely used radiotracer in positron emission tomography is 18F-fluoro-2-deoxy-D-glucose (FDG), which is an analog of glucose. FDG uptake in cells is directly proportional to glucose metabolism of cells. Since glucose metabolism is increased many fold in malignant tumors, positron emission tomography has a high sensitivity and high negative predictive value. Positron emission tomography with FDG is now the standard of care in initial staging, monitoring the response to therapy and management of lung cancer, colorectal cancer, lymphoma, melanoma, esophageal cancer, head and neck cancer and breast cancer. The aim of this article is to review the clinical applications of positron emission tomography in oncology.

Fluid-flow induced wall shear stress and epithelial ovarian cancer peritoneal spreading

Epithelial ovarian cancer (EOC) is usually discovered after extensive metastasis have developed in the peritoneal cavity. The ovarian surface is exposed to peritoneal fluid pressures and shear forces due to the continuous peristaltic motions of the gastro-intestinal system, creating a mechanical micro-environment for the cells. An in vitro experimental model was developed to expose EOC cells to steady fluid flow induced wall shear stresses (WSS). The EOC cells were cultured from OVCAR-3 cell line on denuded amniotic membranes in special wells. Wall shear stresses of 0.5, 1.0 and 1.5 dyne/cm² were applied on the surface of the cells under conditions that mimic the physiological environment, followed by fluorescent stains of actin and β-tubulin fibers. The cytoskeleton response to WSS included cell elongation, stress fibers formation and generation of microtubules. More cytoskeletal components were produced by the cells and arranged in a denser and more organized structure within the cytoplasm. This suggests that WSS may have a significant role in the mechanical regulation of EOC peritoneal spreading.

PET/CT scanning guided intensity-modulated radiotherapy in treatment of recurrent ovarian cancer

OBJECTIVE

This study was undertaken to evaluate the clinical contribution of positron emission tomography using (18)F-fluorodeoxyglucose and integrated computer tomography (FDG-PET/CT) guided intensity-modulated radiotherapy (IMRT) for treatment of recurrent ovarian cancer.

MATERIALS AND METHODS

Fifty-eight patients with recurrent ovarian cancer from 2003 to 2008 were retrospectively studied. In these patients, 28 received PET/CT guided IMRT (PET/CT-IMRT group), and 30 received CT guided IMRT (CT-IMRT group). Treatment plans, tumor response, toxicities and survival were evaluated.

RESULTS

Changes in GTV delineation were found in 10 (35.7%) patients based on PET-CT information compared with CT data, due to the incorporation of additional lymph node metastases and extension of the metastasis tumor. PET/CT guided IMRT improved tumor response compared to CT-IMRT group (CR: 64.3% vs. 46.7%, P=0.021; PR: 25.0% vs. 13.3%, P=0.036). The 3-year overall survival was significantly higher in the PET-CT/IMRT group than control (34.1% vs. 13.2%, P=0.014).

CONCLUSIONS

PET/CT guided IMRT in recurrent ovarian cancer patients improved the delineation of GTV and reduce the likelihood of geographic misses and therefore improve the clinical outcome.

CT, MRI and PET imaging in peritoneal malignancy

Imaging plays a vital role in the evaluation of patients with suspected or proven peritoneal malignancy. Nevertheless, despite significant advances in imaging technology and protocols, assessment of peritoneal pathology remains challenging. The combination of complex peritoneal anatomy, an extensive surface area that may host tumour deposits and the considerable overlap of imaging appearances of various peritoneal diseases often makes interpretation difficult. Contrast-enhanced multidetector computed tomography (MDCT) remains the most versatile tool in the imaging of peritoneal malignancy. However, conventional and emerging magnetic resonance imaging (MRI) and positron emission tomography (PET)/CT techniques offer significant advantages over MDCT in detection and surveillance. This article reviews established and new techniques in CT, MRI and PET imaging in both primary and secondary peritoneal malignancies and provides an overview of peritoneal anatomy, function and modes of disease dissemination with illustration of common sites and imaging features of peritoneal malignancy.

The role of FDG-PET/CT in ovarian cancer patients with high tumor markers or suspicious lesion on contrast-enhanced CT in evaluation of recurrence and/or in determination of intraabdominal metastases

OBJECTIVES

This retrospective study was designed to investigate the role of fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in determination of recurrence and/or intraabdominal metastasis in patients with ovarian cancer having increased tumor markers or suspicious lesion detected by a contrast-enhanced abdominal CT (ceCT).

MATERIALS AND METHODS

A total of 34 female patients who were treated for histopathologically proven ovarian cancer, underwent PET/CT examination for restaging and suspected recurrence. Patients with pathology report, tumor marker levels, ceCT and PET/CT performed within one month were included in the study.

RESULTS

A total of 34 patients were included in the study. 25 of 34 patients had high tumor marker (CA 125) level. The remaining 9 patients had suspected recurrence on ceCT imaging with normal tumor marker levels. Recurrence was confirmed by re-operation and biopsy (n=4), clinical and imaging follow-up (n=21) in 25 patients with elevated tumor markers. Recurrent disease was not shown in 5 of 25 patients on ceCT imaging and 1 of 25 patients on PET/CT imaging with high CA125 values. Both ceCT and PET/CT revealed recurrent disease in 19 of 25 patients. PET/CT showed more lesions in 11 of 19 patients. Sensitivity, specificity and accuracy of the PET/CT were 96.1%, 100% and 97%, respectively.

CONCLUSION

PET/CT is found as a beneficial method for detection of the recurrence, in patients with increased serum CA 125 level and negative CT findings or with normal CA 125 level and recurrence detected by CT which was performed due to clinical symptoms.

Clinical utility of positron emission tomography/computed tomography in the evaluation of suspected recurrent ovarian cancer in the setting of normal CA-125 levels

OBJECTIVES

This study was conducted to estimate the accuracy of [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) as compared with contrast-enhanced CT (CECT) in detecting cancer in patients who have normal cancer antigen (CA)-125 (<35 U/dL) but are suspected of having a recurrent disease based on clinical symptoms.

METHODS

We retrospectively reviewed the records of patients who had undergone primary cytoreductive surgery and subsequently underwent CECT and FDG-PET/CT for suspected recurrence. [18F]-fluorodeoxyglucose positron emission tomography/computed tomography and CECT interpretation to evaluate a recurrent disease was carried out independently by 2 experienced radiologists who were blinded to the final diagnosis for the suspected recurrence. Long-term follow-up imaging (12 months) and biopsy reports were used to assess the true status of the suspected recurrence seen on FDG-PET/CT or CECT. Sensitivity and specificity of all modalities were estimated. McNemar test was used to compare pairs of modalities. All tests were 2-sided, and P < or = 0.05 was considered statistically significant.

RESULTS

Sixty-six patients met the eligibility criteria for inclusion in our analysis. Fifty-eight percent (18/31) and 54% (17/31) of the patients with normal CA-125 levels had evidence of a recurrent disease on FDG-PET/CT and CECT, respectively. Thirty-one percent (6/19) of the patients with no indication of cancer on CECT had evidence of disease on FDG-PET/CT images, which was supported by pathological proof.

CONCLUSION

[18F]-Fluorodeoxyglucose positron emission tomography/computed tomography is capable of detecting ovarian cancer recurrence in symptomatic patients with normal CA-125 levels and, in this setting, has slightly better sensitivity than CECT and can be considered as the frontline modality for all such patients.

Recurrent ovarian cancer: use of contrast-enhanced CT and PET/CT to accurately localize tumor recurrence and to predict patients' survival

PURPOSE

To compare accuracy and interobserver variability in the detection and localization of recurrent ovarian cancer with contrast material-enhanced (CE) computed tomography (CT) and positron emission tomography (PET)/CT and determine whether imaging findings can be used to predict survival.

MATERIALS AND METHODS

Waiving informed consent, the institutional review board approved this HIPAA-compliant, retrospective study of 35 women (median age, 54.4 years) with histopathologically proven recurrent ovarian carcinoma who underwent CE CT and PET/CT before exploratory surgery. All CE CT and PET/CT scans were independently analyzed. Tumor presence, number of lesions, and the size and maximum standardized uptake value (SUV(max)) of the largest lesion were recorded for patient and region. Surgical histopathologic findings constituted the reference standard. Areas under the receiver operating characteristic curves (AUCs), κ statistics, and hazard ratios were calculated.

RESULTS

Readers' AUCs in detection of recurrence for region were 0.85 (95% confidence interval [CI]: 0.81, 0.90) and 0.78 (95% CI: 0.72, 0.83) for CE CT and 0.84 (95% CI: 0.79, 0.89) and 0.74 (95% CI: 0.67, 0.81) for PET/CT (P = .76); 12 patients died. At PET/CT, size, number, and SUV(max) of peritoneal deposits were significantly associated with poor survival for readers 1 and 2 (P ≤ .01and ≤ .05, respectively), as were long- and short-axis diameters, number, and SUV(max) of distant lymph nodes for reader 1 (P ≤ .001). With CE CT, size (reader 1) and number (readers 1 and 3) of peritoneal deposits were significantly associated with poor survival (P ≤ .01), as were long- and short-axis diameters and number of distant lymph nodes for reader 1 (P ≤ .01). Interobserver agreement ranged from fair (patient, κ = 0.30) to moderate (region, κ = 0.55) for CE CT and fair (patient, κ = 0.24) to substantial (region, κ = 0.63) for PET/CT.

CONCLUSION

Preliminary data suggest that CE CT and PET/CT may have similar accuracy in detection of recurrent ovarian cancer. Tumor size, number, and SUV(max) may have potential as prognostic biomarkers for patients with recurrent ovarian cancer.

Secondary tumors and tumorlike lesions of the peritoneal cavity: imaging features with pathologic correlation

Tumors and tumorlike lesions that secondarily involve the mesothelial or submesothelial layers of the peritoneum are a diverse group of disorders that range in biologic behavior from benign to highly malignant. The anatomy of peritoneal ligaments and mesenteries and the normal circulation of peritoneal fluid dictate location and distribution of these diseases within the peritoneal cavity. Peritoneal carcinomatosis is the most common secondary tumor to affect the peritoneal cavity. When it arises from carcinomas of the gastrointestinal tract or ovary, the prognosis is grave. However, when low-grade mucinous adenocarcinoma of the appendix spreads to the peritoneal cavity, the consequence is typically pseudomyxoma peritonei, which is a clinical syndrome, characterized by recurrent and recalcitrant voluminous mucinous ascites due to surface growth on the peritoneum without significant invasion of underlying tissues. Carcinomas from elsewhere in the body, as well as lymphomas and sarcomas, may also produce diffuse peritoneal metastasis. Granulomatous peritonitis is the consequence of disseminated infection such as tuberculosis or histoplasmosis, foreign materials, or rupture of a tumor or hollow viscus. Finally, a group of benign miscellaneous conditions that range from common disorders such as endometriosis and splenosis to very rare conditions such as gliomatosis peritonei and melanosis may also affect the peritoneum diffusely. Secondary tumors and tumorlike lesions of the peritoneum have overlapping imaging features when compared with each other and primary peritoneal tumors. Knowledge of peritoneal anatomy, normal fluid circulation within the peritoneal cavity, and clinical and pathologic features of secondary peritoneal lesions is essential for identification of these lesions.

The impact of PET-CT in suspected recurrent ovarian cancer: A prospective multi-centre study as part of the Australian PET Data Collection Project

OBJECTIVE

To assess the impact of FDG PET-CT on the management of patients with suspected recurrent ovarian cancer and to determine the incremental information provided by PET-CT.

METHODS

This was a prospective, multi-centre, cohort study. Ninety women (mean age 59.9 years; age range 35-85 years) with a previous history of treated epithelial ovarian carcinoma and suspected recurrence based on elevated CA-125, anatomical imaging or clinical symptoms were studied with FDG PET-CT across two States. Referring doctors were asked to specify a management plan pre-PET, if management was altered after PET-CT and, the impact (rated - none, low, medium, high) of PET-CT on patient management. The pre-PET management plan could include radiotherapy, chemotherapy, surgery, and 'other' including observation. Patients were followed at 6 and 12 months and clinical status, evidence of recurrence and progression were recorded.

RESULTS

Patients were referred by 34 individual specialists. At least 168 additional sites of disease in 61 patients (68%), not identified by conventional imaging were identified by PET-CT. In 77% the additional lesions were located below the diaphragm and most were nodal or peritoneal. PET-CT affected management in 60% (49% high, 11% medium impact). Patients where more disease was detected with PET-CT were more likely to progress in the following 12 months.

CONCLUSIONS

For women with previously treated ovarian carcinoma with recurrent disease, PET-CT can: a) alter management in close to 60% of patients, b) detect more sites of disease than abdominal and pelvic CT, c) is superior in the detection of nodal, peritoneal and subcapsular liver disease and d) offers the opportunity for technology replacement in this setting.

Discordant MRI/FDG-PET imaging for the diagnosis of borderline ovarian tumors

The objective of this study was to assess the role of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) for the characterization of ovarian masses that were diagnosed as ovarian malignancies by magnetic resonance imaging (MRI). We performed a retrospective review of eight patients with pathologically confirmed borderline ovarian tumors (BOT) who underwent MRI and FDG-PET before surgical staging from August 2005 to March 2007. We assessed the PET imaging of the BOT, measured the FDG uptake and quantified the findings as a standardized uptake value (SUV). The FDG-PET scans, of all eight patients, showed uptake of FDG with a mean SUV of less than 2.0 in the solid portion of the masses evaluated. We conclude that the MRI-PET differences may help differentiate borderline from malignant ovarian tumors.

Discrepancy between magnetic resonance and 18F-fluorodeoxyglucose positron emission tomography imaging in a case of borderline ovarian tumor

Borderline ovarian tumors have a far more favorable clinical course compared to malignant ovarian tumors. To date, the role of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for the differentiation of an ovarian mass remains controversial. Discrepancy between FDG-PET and magnetic resonance (MR) images is rare but may cause a serious dilemma in decision-making. We report a case of a borderline ovarian tumor showing discrepancy between MR and FDG-PET findings. FDG-PET findings may help with the differentiation of ovarian masses when clinical findings are not coincidental.

Ovarian cancer

Imaging has become an essential part of the clinical management of patients with ovarian cancer, contributing to tumor detection, characterization, staging, treatment planning, and follow-up. Imaging findings incorporated into the clinical impression assist in creating a treatment plan specific for an individual patient. Advances in cross-sectional imaging and nuclear medicine (PET) have yielded new insights into the evaluation of tumor prognostic factors. A multimodality approach can satisfy the complex imaging needs of a patient with ovarian cancer; however, the success of such an approach always depends on available resources and on the skills of the physicians involved.

MRI evaluation of bulky tumor masses in the mesentery and bladder involvement in peritoneal carcinomatosis

AIM

Peritonectomy procedures with intraperitoneal chemohyperthermia are an effective but costly treatment for peritoneal carcinomatosis (PC). Consequently a proper selection of patients is necessary. We evaluated the benefit of MRI prior to surgery, in the detection of two of the main surgery contraindications: bulky mesenteric tumors and bladder implants.

METHODS

Three experts retrospectively reviewed abdominal and pelvic MRI from 19 cases of surgically proved PC (ovary: 7; colorectal: 7; gastric: 2; pseudomyxoma peritonei: 2; appendix: 1).

RESULTS

Mesenteric tumors were always identified as hypersignal masses on axial and coronal fat suppression gadolinium-enhanced T1 images (n=3). Three out of five bladder implants were detected. The two cases of bladder implants that were not detected on MRI were missed because the bladder was not filled. The best sequence for the detection of bladder involvement was axial T2-weighted images with bladder filling.

CONCLUSIONS

Evaluating the preoperative resectability of PC is crucial for patient management. MRI seems to reliably detect bulky mesenteric tumors and bladder implants on condition the bladder is filled and appropriate sequences are used.

Role of [18F]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 (kappa = 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.

Imaging of pelvic malignancies with in-line FDG PET-CT: case examples and common pitfalls of FDG PET

The role of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in combination with computed tomography (CT) in the evaluation of pelvic malignancies has been rapidly growing in recent years. FDG PET has proved to be valuable in the evaluation of a variety of pelvic malignancies, including colorectal cancer, uterine cervical cancer, ovarian cancer, endometrial cancer, and non-Hodgkin lymphoma. However, a number of pitfalls are commonly encountered at FDG PET, including normal physiologic activity in bowel, ovaries, endometrium, and blood vessels and focal retained activity in ureters, bladder diverticula, pelvic kidneys, and urinary diversions. The use of an in-line FDG PET-CT system, with special attention given to proper patient preparation and scanning protocol, often provides valuable information to help localize and define disease and avoid potential diagnostic pitfalls.

Evaluation of integrated whole-body PET/CT in the detection of recurrent ovarian cancer

PURPOSE

To assess the usefulness and reliability of integrated whole-body positron emission tomography/computed tomography (PET/CT) in patients in whom recurrent ovarian cancer is suspected.

METHODS

Integrated whole-body PET/CT imaging was performed in 19 patients with suspected ovarian cancer recurrence. CT, PET and fused PET/CT images were evaluated separately and imaging results were compared with pathological findings and clinical follow-up after 6 months.

RESULTS

Of the 19 patients studied, 11 were found to have recurrent cancer. In 8 of these 11 patients, recurrence was diagnosed by CT, PET and fused PET/CT. In the remaining three patients, only PET and PET/CT showed a recurrent tumour, while CT was negative. Twelve localisations of ovarian cancer recurrence could be detected by CT, 17 by PET and 18 by PET/CT. In one patient with pulmonary metastases in CT and in the CT component of PET/CT, PET was negative. In the case of three metastases in the diaphragm, the spleen and the thoracic wall, respectively, the determination of the exact localisation was only possible by fused PET/CT.

CONCLUSION

In patients with recurrent ovarian cancer, PET/CT detects more lesions than PET or CT alone. PET/CT permits the exact anatomical localisation of pathologic tracer uptake and can thus direct further treatment to the precise site of tumour recurrence. Hence, PET/CT should be considered for follow-up of patients with ovarian cancer.

Positron emission tomography application for gynecologic tumors

Positron emission tomography (PET) using fluorine-18-fluoro-2-deoxy-d-glucose (FDG), which originated as a research tool to evaluate glucose metabolism in cancer tissues, has now become an essential imaging modality for determining the appropriate therapeutic management of various cancer patients. The clinical role of FDG-PET for gynecologic tumors has not been established yet, but FDG-PET has come to be considered one of the important imaging modalities for evaluating patients with gynecological cancers. The objective was to review the literature regarding the utility of FDG-PET in the clinical setting of gynecological malignancies. Many articles reported that FDG-PET could be used for staging and restaging in patients with uterine cervical cancer. Although there is limited data about the feasibility of FDG-PET for endometrial cancer, preliminary results for detecting recurrence were promising. Furthermore, FDG-PET has been reported as a useful imaging modality, especially for restaging, in ovarian cancer, although the prognostic value needs to be fully investigated. Currently, a combined PET/computed tomography scanner is available, and its clinical application has begun. It is expected that this modality will contribute to the management of gynecological cancers, as has been reported recently for other malignancies.

18F-FDG PET/CT in the evaluation of recurrent ovarian cancer: a prospective study on forty-one patients

AIM

Many patients with ovarian cancer are at high risk of recurrence especially in the 2 years following first-line therapy. CA125 serum levels measurement associated to computed tomography (CT), ultrasound (US) and magnetic resonance imaging (MRI) are currently used during follow-up to detect recurrent disease. Unfortunately, in a relevant percentage of cases all of these traditional imaging techniques provide a significant number of doubtful/equivocal results or turn out negative even in presence of elevated Ca125 levels. Aim of our study was to evaluate sensitivity, specificity and accuracy of (18)F-FDG PET/CT in a group of patients with suspicion of ovarian cancer recurrence.

METHODS

We prospectively evaluated 41 patients with a mean age of 59.4 years who had been previously treated for ovarian cancer with surgery and radio-chemotherapy or radio-chemotherapy alone. Following the performance of traditional radiologic imaging (US, CT, MRI) and Ca125 measurement, all patients underwent additional (18)F-FDG PET/CT. PET/CT results were compared with histologic findings or clinical, laboratory and repeated traditional imaging techniques during subsequent follow-up data.

RESULTS

Of 41 patients 32 had a positive PET-CT (30 true positive, two false positive) whereas nine a negative PET/CT (five true negative, four false negative). Overall, in our experience (18)F-FDG PET/CT provided a good sensitivity (88.2%), specificity (71.4%) and accuracy (85.4%), superior to that reported in literature for traditional radiologic imaging.

CONCLUSIONS

It can be concluded that (18)F-FDG PET/CT appears to be a useful and accurate tool in disclosing early recurrent ovarian cancer.

Tumor Lesion Detection

OBJECTIVES

To determine if there is added value to oncology studies performed with a dedicated in-line positron emission tomography (PET)/computed tomography (CT) scanner as compared with PET read side by side with diagnostic CT (DCT).

METHODS

Forty-one consecutive oncology patients referred for PET/CT who had contemporary DCT scans for review were enrolled. Body regions assessed on a DCT scan were assessed on PET/CT and by side-by-side reading of PET and DCT (SBS PET/DCT). Lesions identified on DCT, the CT portion of PET/CT, SBS PET/DCT, and the reading of fused PET/CT images were scored as benign or malignant. The PET portion of the PET/CT study was read by 2 teams: the first read the SBS PET/DCT scan and the other read the complete fused PET/CT scan. For discordant lesions, the final diagnosis was determined by pathologic findings (n = 6) or imaging follow-up (n = 21).

RESULTS

Twenty-seven (16.1%) of the 168 lesions were discordant when comparing analysis of fused PET/CT and SBS PET/DCT. Sixteen (9.5%) were fundamentally discordant, and 11(6.6%) were discordant in degree of confidence. For all discordant lesions only, the sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for PET/CT were 100%, 33%, 100%, 94%, and 78%, respectively, and for SBS PET/DCT, they were 38%, 50%, 19%, 73%, and 30%, respectively (P < 0.001 for sensitivity, P = not specific for specificity). The 2 main causes for misclassification on SBS PET/DCT were incorrect localization (n = 12) and changes occurring in the time gap between DCT and PET/CT (n = 4).

CONCLUSIONS

In-line PET/CT offers better lesion localization in comparison to the visual fusion of PET and CT, especially for small lymph nodes, lesions adjacent to mobile organs, or lesions adjacent to the chest or abdominal wall.

Issues, Controversies, and Clinical Utility of Combined PET/CT Imaging: What Is the Interpreting Physician Facing?

OBJECTIVE

This article identifies the most commonly encountered issues of combined PET/CT and shows the wide variability in perceived possible solutions to these issues. This article will serve as a catalyst to stimulate discussion between experts in both radiology and nuclear medicine.

CONCLUSION

Combining a PET tomography and CT scanner into a single unit amounts to advantages that are not merely additive, but synergistic. Even PET/CT skeptics will embrace the technology after becoming acquainted with the possibilities and will accept the reality that there is no return to PET only.

Laparoscopic resection of occult metastasis using the combination of FDG-positron emission tomography/computed tomography image fusion with intraoperative probe guidance in a woman with recurrent ovarian cancer

BACKGROUND

Positron emission tomography and computed tomography (PET/CT) have a potential role in detecting and locating recurrent ovarian cancer. Precise tumor location during surgical treatment is often difficult, owing to limited tumor size and post-surgical anatomic modifications. The surgical gamma probe, which has become increasing popular in recent years with the development of sentinel node mapping, may improve tumor detection and facilitate resection of occult metastases.

CASE REPORT

We describe the first case of laparoscopic resection of occult metastasis using the combination of FDG-PET/CT image fusion with intraoperative FDG-sensitive probing in a patient with recurrent ovarian cancer.

CONCLUSION

FDG-sensitive probe combined with preoperative PET/CT image fusion can help to detect occult metastasis and guide laparoscopic excision.