Physiological 18F-FDG uptake in the ovaries and uterus of healthy female volunteers

Multimodality imaging of ovarian cystic lesions: Review with an imaging based algorithmic approach

Ovarian cystic masses include a spectrum of benign, borderline and high grade malignant neoplasms. Imaging plays a crucial role in characterization and pretreatment planning of incidentally detected or suspected adnexal masses, as diagnosis of ovarian malignancy at an early stage is correlated with a better prognosis. Knowledge of differential diagnosis, imaging features, management trends and an algorithmic approach of such lesions is important for optimal clinical management. This article illustrates a multi-modality approach in the diagnosis of a spectrum of ovarian cystic masses and also proposes an algorithmic approach for the diagnosis of these lesions.

The role of FDG-PET/CT in gynaecological cancers

There is now a growing body of evidence supporting the use of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in gynaecological malignancies. Although this molecular imaging technique is becoming increasingly available, PET/CT remains an expensive imaging tool. It is essential to be familiar with the circumstances in which FDG-PET/CT can add value and contribute to patient management and indeed to know when it is unlikely to be of benefit. It is also important to understand and recognize the potential pitfalls. FDG-PET/CT has been most widely adopted for staging patients with suspected advanced disease or in suspected recurrence, offering a whole-body imaging approach. However, there is great potential for this technique to act as a predictive biomarker of response to treatment, as well as a prognostic biomarker. In addition, FDG-PET images may now be incorporated into radiotherapy planning in order to refine the delineation of dose according to metabolically active sites of disease. This article reviews the literature that provides the evidence for the use of FDG-PET in gynaecological malignancies, identifies areas of real benefit and future potential, and highlights circumstances where there is limited value.

(18)F-FDG Uptake of Human Testis on PET/CT: Correlation with Age, Sex Hormones, and Vasectomy

PURPOSE

The purpose of this study was to evaluate glucose metabolism of normal human testis on (18)F-FDG PET/CT and to assess possible correlations among age, the serum levels of sex hormones, and vasectomy.

METHODS

(18)F-FDG PET/CT was performed in 66 normal healthy men (50.8 ± 13.6 years, range 22-81), and mean standard uptake values (SUV) of (18)F-FDG in testis and adductor muscle were measured. Testis-muscle SUV ratios (T/M ratios) were calculated. Serum levels of total testosterone, free testosterone, estradiol, and of sex-hormone binding globulin (SHBG) were measured. We searched for correlations between T/M ratios and age and the serum concentrations of sex hormones. (18)F-FDG PET/CT was also performed in 32 vasectomized men (55.7 ± 7.8 years, range 38-71) and 52 nonvasectomized men (55.4 ± 11.6 years, range 37-72). Mean SUVs of testis and adductor muscle were measured, and T/M ratios were calculated.

RESULTS

A significant age-related decline was found in T/M ratio (r = -0.509, p < 0.0001). Serum levels of total testosterone and free testosterone were also found to be positively correlated with T/M ratio (r = 0.427, p = 0.0003; r = 0.435, p = 0.0003, respectively). The mean SUV and T/M ratio of vasectomized men were significantly lower than those of nonvasectomized men (p < 0.0378 and p = 0.0001, respectively).

CONCLUSIONS

Glucose metabolism in the testis in an adult population was found to be correlated with age, serum sex hormone level, and vasectomy history. These results indicate that testicular (18)F-FDG uptake may have attributed to testicular function and testicular histology. Our findings may have important implications for the interpretation of testicular (18)F-FDG uptake in the normal adult population.

False-positive uptake on 2-[¹⁸F]-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) in oncological imaging

With the increasing utilization of integrated positron-emission tomography/computed tomography (PET/CT) using the glucose analogue 2-[¹⁸F]-fluoro-2-deoxy-D-glucose (FDG) in oncological imaging, it is important for radiologists and nuclear medicine physicians to be aware that FDG uptake is not specific for malignancy, as many different physiological variants and benign pathological conditions can also exhibit increased glucose metabolism. Such false-positive FDG uptake often arises outside the area of primary interest and may mimic malignant disease, thereby confounding accurate interpretation of PET/CT studies. With the use of illustrative clinical cases, this article will provide a systematic overview of potential interpretative pitfalls and illustrate how such unexpected findings can be appropriately evaluated.

Physiology and pathophysiology of incidental findings detected on FDG-PET scintigraphy

A routine feature of positron emission tomography/computed tomography (PET/CT) imaging is whole-body acquisition that results in many unexpected findings identified outside of the primary region of abnormality. Furthermore, (18)F-fluorodeoxyglucose (FDG) is a marker of glycolysis and does not specifically accumulate in malignancy. Understanding the physiology and pathophysiology of normal FDG distribution and common incidental findings is therefore essential to the physician interpreting whole-body FDG-PET/CT studies. Whereas many incidental findings are benign and of limited clinical significance, others represent uncommon manifestations of the primary malignancy, second malignancies, or various clinically significant pathologic processes. Patients with a single malignancy are at greater risk of developing synchronous or metachronous second malignancies, possibly related to exposure to shared carcinogenic agents or presence of prooncogenic mutations. The decision of how to pursue an intervention on the basis of an incidental finding is generally left to clinical judgment.

Ovarian mass mimicking malignancy: a case report

A 32-year-old female who suffered from abdominal pain underwent (18)F-fluorodexoyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for the diagnostic workup of pelvic mass lesions. Cystic mass lesions in the bilateral ovaries showed wall thickening and intense hypermetabolism along the rim. In addition, multifocal intense hypermetabolic lymphadenopathies were seen in the left paraaortic lymph node (LN), aortocaval LN, and both common iliac LNs. We interpreted these findings as bilateral ovarian cancer with retroperitoneal metastatic lymphadenopathies rather than endometriosis with reactive lymphadenopathies. However, histopathological examination confirmed the ovarian mass lesions as tubo-ovarian abscesses. We report a case that even if simultaneous hypermetabolic retroperitoneal LNs are seen, intense hypermetabolic lesions in both ovaries can be in consequence of inflammatory change.

MRI, CT, and PET/CT for ovarian cancer detection and adnexal lesion characterization

OBJECTIVE

The purpose of this article is to describe the role of MR, CT, and PET/CT in the detection of ovarian cancer and the evaluation of adnexal lesions.

CONCLUSION

The goal of imaging in ovarian cancer detection is to expeditiously distinguish benign adnexal lesions from those requiring further pathologic evaluation for malignancy. For lesions indeterminate on ultrasound, MRI increases the specificity of imaging evaluation, thus decreasing benign resections. CT is useful in diagnosis and treatment planning of advanced cancer. Although (18)F-FDG-avid ovarian lesions in postmenopausal women are considered suspicious for malignancy, PET/CT is not recommended for primary cancer detection because of high false-positive rates.

Positron emission tomography in ovarian cancer: 18F-deoxy-glucose and 16alpha-18F-fluoro-17beta-estradiol PET

The most frequently used molecular imaging technique is currently 18F-deoxy-glucose (FDG) positron emission tomography (PET). FDG-PET holds promise in the evaluation of recurrent or residual ovarian cancer when CA125 levels are rising and conventional imaging, such as ultrasound, CT, or MRI, is inconclusive or negative. Recently, integrated PET/CT, in which a full-ring-detector clinical PET scanner and a multidetector helical CT scanner are combined, has enabled the acquisition of both metabolic and anatomic imaging data using one device in a single diagnostic session. This can also provide precise anatomic localization of suspicious areas of increased FDG uptake and rule out false-positive PET findings. FDG-PET/CT is an accurate modality for assessing primary and recurrent ovarian cancer and may affect management. FDG-PET/CT may provide benefits for detection of recurrent of ovarian cancer and improve surgical planning. And FDG-PET has been shown to predict response to neoadjuvant chemotherapy and survival in advanced ovarian cancer. This review focuses on the role of FDG-PET and FDG-PET/CT in the management of patients with ovarian cancer. Recently, we have evaluated 16α-18F-fluoro-17β-estradiol (FES)-PET, which detects estrogen receptors. In a preliminary study we reported that FES-PET provides information useful for assessing ER status in advanced ovarian cancer. This new information may expand treatment choice for such patients.

Prospective evaluation of whole-body cancer screening with multiple modalities including [18F]fluorodeoxyglucose positron emission tomography in a healthy population: a preliminary report

PURPOSE

To prospectively evaluate the utility of whole-body cancer screening with multiple modalities including [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) in a healthy population. This report summarizes the results of the first three annual screenings.

PARTICIPANTS AND METHODS

A total of 1,197 healthy volunteers > or = 35 years old were enrolled between August 2003 and July 2004 and offered annual cancer screening for 5 years with subsequent long-term follow-up. Screening modalities included were whole-body FDG-PET, chest and abdominal computed tomography (CT), brain and pelvic magnetic resonance imaging, several tumor markers, and fecal occult blood testing.

RESULTS

As of the end of 2006, 22 primary cancers were pathologically confirmed. Nineteen of 22 were detected by the screening; 18 in the initial, one in the second, and none in the third. Three were diagnosed after development of symptoms. Of the 18 detected in the initial screening (six thyroid, four lung, three prostate, three breast, one endometrial, and one thymic), 12 were at stage I and 11 were PET positive. PET-negative cancers were detected by CT or the prostate-specific antigen (PSA) test. Sensitivity and specificity were 50.0% (11 of 22) and 93.2% (1,095 of 1,175), respectively, for FDG-PET alone and 81.8% (18 of 22) and 82.0% (963 of 1,175), respectively, for the combination of imaging modalities and PSA.

CONCLUSION

While FDG-PET alone is insufficient, whole-body cancer screening with selected modalities including FDG-PET has initial performance supporting possible utility by detecting a wide variety of early-stage cancers with reasonable sensitivity. However, the detection of many indolent cancers and false positives necessitate continuing study for appropriate evaluation.

Frequency and etiology of solitary hot spots in the pelvis at whole-body positron emission tomography/computed tomography imaging

PURPOSE

To determine the frequency and etiology of a single hypermetabolic focus within the pelvis with no other areas of increased 18-fluorodeoxyglucose (FDG) uptake in the reminder of the whole body in an oncological population.

METHOD AND MATERIALS

We retrospectively examined the first 700 whole-body PET/CT scans performed at our institution for baseline staging or follow-up of cancer and identified all patients with a solitary focus of increased FDG uptake in the pelvis. All available medical records and imaging findings in these patients were reviewed in order to determine the etiology of increased FDG uptake.

RESULTS

Eight (1.1%) of the 700 patients had a solitary hot spot in the pelvis at positron emission tomography (PET)/computed tomography (CT) imaging, consisting of seven of 380 women and one of 320 men. In the seven women, increased FDG uptake was due to physiological endometrial uptake (n=2), leiomyoma (n=1), corpus luteum cyst (n=1), physiological ovarian uptake (n=1), urinary leak (n=1), and nonspecific colitis (n=1). In the man, uptake was due to recurrent rectosigmoid adenocarcinoma. None of the 700 patients was found to have metastatic disease in the pelvis.

CONCLUSION

Isolated pelvic hot spots at PET/CT imaging in an oncological population are not common and usually benign; physiological endometrial or ovarian uptake is the single commonest cause.

Incidence and characteristics of uterine leiomyomas with FDG uptake

OBJECTIVE

Uterine leiomyomas sometimes show focal 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) images that may result in a false-positive diagnosis for malignant lesions. This study was conducted to investigate the incidence and characteristics of uterine leiomyomas that showed FDG uptake.

METHODS

We reviewed FDG-PET and pelvic magnetic resonance (MR) images of 477 pre-menopausal (pre-MP, age 42.1 +/- 7.3 years) and 880 post-MP (age 59.9 +/- 6.8 years) healthy women who underwent these tests as parts of cancer screening. Of 1357, 323 underwent annual cancer screening four times, 97 did three times, 191 did twice, and the rest were screened once. Focal FDG uptake (maximal standardized uptake value > 3.0) in the pelvis was localized and characterized on co-registered PET/MR images.

RESULTS

Uterine leiomyomas were found in 164 pre-MP and 338 post-MP women. FDG uptake was observed in 18 leiomyomas of 17 of the 164 (10.4%) pre-MP women and in 4 leiomyomas of 4 of the 338 (1.2%) post-MP women. The incidence was significantly higher in pre-MP women than in post-MP women (chi-square, P < 0.001). Of the 22, 13 showed signal intensity equal to or higher than that of the myometrium on T2-weighted MR images, which suggested abundant cellularity, whereas the majority of leiomyomas without FDG uptake showed low signal intensity. Of the 13 women, 12 examined more than twice showed substantial changes in the level of FDG uptake in leiomyomas each year with FDG uptake disappearing or newly appearing. These changes were observed frequently in relation with menopause or menstrual phases.

CONCLUSIONS

Leiomyomas with focal FDG uptake were seen in both pre-and post-MP women with a higher incidence in pre-MP women. Abundant cellularity and hormonal dependency may explain a part of the mechanisms of FDG uptake in leiomyomas. It is important to know that the level of FDG uptake in leiomyomas can change and newly appearing FDG uptake does not necessarily mean malignant transformation.

[Potential sources of diagnostic pitfall and variants in FDG-PET/CT]

Oncological FDG PET show variants and findings that may lead to a diagnostic error and that may be clarified by the morfofunctional imaging from PET/CT. In this article we show the experience acquired since a Siemens PET/CT Biograph LSO Pico3D was applied in our centre. We describe some representative examples of FDG distribution patterns which may lead to erroneous interpretations of the clinical studies when they refer to specific clinical situations. The examples included are classified into two main groups according to the cause: Technical and biological, and the latter into physiological and non-physiological (pathophysiological). Patterns are described within the biological group showing changes of the FDG biodistribution that may reduce the uptake in tumoural lesions, the physiological variants that may be interpreted as pathology, the effects of previous treatment and uptakes related to benign diseases.

CONCLUSION

We consider that knowledge of these variants and findings to be crucial in order to obtain optimal performance of PET/CT and to overcome the PET limitations.

Uterine tumors: pathophysiologic imaging with 16alpha-[18F]fluoro-17beta-estradiol and 18F fluorodeoxyglucose PET--initial experience

PURPOSE

To clarify prospectively the relationship between estrogen receptor (ER) expression and glucose metabolism by using 16alpha-[(18)F]fluoro-17beta-estradiol (FES) and fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients with benign and malignant uterine tumors.

MATERIALS AND METHODS

The institutional review board approved this study, and informed consent was obtained from all subjects. FES and FDG PET studies were performed in 38 patients (mean age, 54.1 years +/- 14.0 [standard deviation]) with benign and malignant uterine tumors to compare differences in tracer accumulation. Regional values of tracer uptake were evaluated by using standardized uptake value (SUV), a normalized value corrected by using injection dose and body weight.

RESULTS

Patients with endometrial carcinoma showed significantly greater mean SUV for FDG (9.6 +/- 3.3) than for FES (3.8 +/- 1.8) (P < .005). Patients with endometrial hyperplasia showed significantly higher mean SUV for FES (7.0 +/- 2.9) than for FDG (1.7 +/- 0.3) (P < .05). Patients with leiomyoma showed significantly higher mean SUV for FES (4.2 +/- 2.4) than for FDG (2.2 +/- 1.1) (P < .005), and patients with sarcoma showed opposite tendencies for tracer accumulation. Tracer uptake in patients with endometrial carcinoma was significantly higher for FDG (P < .001) and significantly lower for FES (P < .05) when compared with values in patients with endometrial hyperplasia. On the other hand, patients with sarcoma showed a significantly higher uptake for FDG (P < .005) and a significantly lower uptake for FES (P < .05) compared with patients with leiomyoma.

CONCLUSION

ER expression and glucose metabolism of uterine tumors measured by using PET showed opposite tendencies. PET studies with both FES and FDG could provide pathophysiologic information for the differential diagnosis of uterine tumors.

FDG-PET Is Useful in Staging and Follow-up of Primary Uterine Cervical Lymphoma

A 35-year old woman presented with vaginal bleeding. She had a normal gynecologic examination and Papanicolaou test. A CT scan of the pelvis showed a cervical mass, which on biopsy proved to be B-cell lymphoma. PET before preoperative staging demonstrated a large area of increased FDG uptake in the pelvis, corresponding to the mass seen on the CT scan. There were no other abnormal F-18 FDG avid sites. The patient received chemotherapy followed by total abdominal hysterectomy. Histopathology was consistent with large B-cell lymphoma of the uterine cervix. Posttherapy CT scan and PET scan showed no evidence of active and or residual disease.

Physiological FDG uptake in the ovaries after hysterectomy

OBJECTIVE

It is known that focal 18F-fluorodeoxyglucose (FDG) uptake is physiologically seen in the ovaries and uterus of premenopausal women in correlation with the menstrual cycle, which may cause false-positive diagnoses on the images of FDG positron emission tomography (PET). The objective of this study was to clarify whether women of reproductive age after hysterectomy whose ovaries were preserved, also showed physiological ovarian FDG uptake.

METHODS

We reviewed 26 women after hysterectomy (age 51.1 +/- 5.0 years), who underwent annual cancer screening, including FDG-PET and pelvic magnetic resonance (MR) imaging, three times.

RESULTS

Seven women (age 45.9 +/- 5.8 years, range 34-52 years) had at least one ovary, showing changes in its appearance including the size and number of follicles on MR images each year, which suggested that the ovary was functioning. Four of the seven women showed focal FDG uptake (standardized uptake value 4.2 +/- 1.1) that corresponded to the normal ovaries on five PET examinations. Another group of 19 women (age 53.1 +/- 3.1 years, range 47-59 years) who had small ovaries without changes on MR images each year did not show FDG uptake in the ovaries.

CONCLUSIONS

Physiological FDG uptake observed in the ovaries of women of reproductive age even after hysterectomy is reasonably common. As it is not easy to determine the hormonal cycle in these women, it is essential to correlate focal FDG uptake in the pelvis with anatomical and morphological findings on MR images to avoid false-positive diagnoses.

Standardized uptake value atlas: characterization of physiological 2-deoxy-2-[18F]fluoro-D-glucose uptake in normal tissues

PURPOSE

The purpose of this study was to map the distribution of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) uptake in organs of patients with no known abnormalities in those tissues.

PROCEDURES

We measured maximum and mean standardized uptake values (SUV) from FDG-positron emission tomography (PET)/computed tomography (CT) obtained from 98 patients (48 males and 50 females).

RESULTS

Significant uptake (mean SUVmean>2.5) was visualized in the cerebellum (8.0+/-2.2), soft palate (2.92+/-0.86), palatine tonsils (3.45+/-1.4), lingual tonsils (3.08+/-1.05), sublingual glands (3.3+/-1.5), and testes (2.57+/-0.56). Negative correlation for FDG uptake versus age was observed for the palatine tonsils, sublingual glands, and lungs (P<0.001).

CONCLUSION

Better understanding of physiological uptake throughout the body is valuable for improved interpretive accuracy and should be useful for future semi-automated comparisons to a normal SUV database.

Age-Related Structural and Metabolic Changes in the Pelvic Reproductive End Organs

In this work, we provide preliminary data and a review of the literature regarding normal structural and functional changes that occur in the aging uterus, ovary, testicle, and prostate gland. It is expected that such knowledge will help physicians to distinguish physiologic changes from pathologic changes at an early stage. We retrospectively reviewed pelvic magnetic resonance imaging (MRI) scans of 131 female and 79 male subjects ages 13 to 86 years to determine changes in volume of the uterus, ovary, and prostate gland with age. Scrotal ultrasound examinations of 150 male subjects ages 0 to 96 years also were analyzed retrospectively to determine changes in testicular volume with age. In addition, (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) scans of 145 male subjects ages 11 to 90 years were analyzed retrospectively to assess for changes in maximum standardized uptake value (SUV(max)) of the testicles with age. The uterus had a mean volume of 38.55 +/- 3.68 cm(3) at 17 to 19 years of age, increased to a peak volume of 71.76 +/- 19.81 cm(3) between 35 to 40 years, and then declined to 24.02 +/- 8.11 cm(3) by the eighth decade of life. The maximal ovarian volume per subject maintained a relatively stable size in early life, measuring 9.46 +/- 3.25 cm(3) during the second decade of life, 8.46 +/- 3.32 cm(3) in the mid-fourth decade of life, and 7.46 +/- 3.33 cm(3) at 45 years of age, after which it declined to 4.44 +/- 2.02 cm(3) by the late fifth decade of life. The ovaries were not identifiable on MRI in subjects beyond the sixth decade of life. The volume of the prostate increased from 23.45 +/- 6.20 cm(3) during the second decade of life to 47.5 +/- 41.59 cm(3) by the late eighth decade of life; the central gland of the prostate increased from 9.96 +/- 3.99 cm(3) to 29.49 +/- 28.88 cm(3) during the same age range. Mean testicular volume was 11.2 +/- 5.9 cm(3). Testicular volume increased with age from birth to 25 years. After age 25, there was a significant decline in the testicular volume. The mean SUV(max) for the testicles was 1.9 +/- 0.5. Testicular metabolic activity demonstrated an increasing trend until the age of 35 years. A plateau in SUV(max) was observed after the age of 35 years until the age of 65 years. A slight decrease in SUV(max) was observed after the age of 65 years. The pelvic structures of men and women change both structurally and functionally over the lifespan, and such changes can be quantified using ultrasound, MRI, and (18)F-FDG-PET.

In vivo imaging of estrogen receptor concentration in the endometrium and myometrium using FES PET — influence of menstrual cycle and endogenous estrogen level

PURPOSE

The goals of this study were to measure estrogen receptor (ER) concentration in the endometrium and myometrium using 16alpha-[(18)F]fluoro-17beta-estradiol (FES) positron emission tomography (PET) and to investigate the relationship between changes in these parameters with the menstrual cycle and endogenous estrogen levels.

METHODS

Sixteen female healthy volunteers were included in this study. After blood sampling to measure endogenous estrogen level, FES PET image was acquired 60 min postinjection of FES. After whole-body imaging of FES PET, averaged standardized uptake values (SUVs) in the endometrium and myometrium were measured, and the relationship between FES uptake and menstrual cycle or endogenous estrogen level was evaluated.

RESULTS

Endometrial SUV was significantly higher in the proliferative phase than in the secretory phase (6.03+/-1.05 vs. 3.97+/-1.29, P=.022). In contrast, there was no significant difference in myometrial SUV when the proliferative and secretory phases were compared (P=.23). Further, there was no correlation between SUV and endogenous estrogen level in the proliferative phase.

CONCLUSIONS

The change of ER concentration relative to menstrual cycle as characterized by FES PET was consistent with those from previous reports that used an immunohistochemical technique. These data suggest that FES PET is a feasible, noninvasive method for characterizing changes in ER concentration.

F-18 fluorodeoxyglucose uptake in leiomyomatous uterus

Leiomyomas of uterus are common disease in gynecology. It is important to differentiate leiomyoma from leiomyosarcoma at the decision of treatment methods, especially in the case of the conservative treatment for uterine leiomyoma. But the exact diagnosis of benign leiomyoma is often difficult due to the degeneration of myoma by imaging modalities including magnetic resonance imaging. Recently, whole-body positron emission tomography (PET) using F-18 fluorodeoxyglucose (FDG) has been used for a diagnosis of malignant tumors. There is a growing body of evidence for the use of FDG in differentiating malignant from benign disease. But optimal utilization in gynecology remains unclear. Our case represents increased uptake of FDG in myomatous uterus, which is pathologically confirmed benign leiomyoma by the hysterectomy. Immunohistochemical analysis of glucose transporter-1 showed positive in endometrial tissue and negative in leiomyoma. Our case indicates that myomatous uterus in premenopausal women shows the potential pitfall of a positive result of FDG-PET.

Endometrial and ovarian F-18 FDG uptake in serial PET studies and the value of delayed imaging for differentiation

PURPOSE

This study was designed to characterize the physiological endometrial and ovarian F-18 FDG uptake through analysis of clinical patients with serial PET follow ups (group 1) or who underwent delayed imaging (group 2).

METHODS

Group 1 had 24 patients (14 premenopausal and 10 postmenopausal). Each patient underwent 2 to 4 serial FDG PET studies and summed to 57 studies. Group 2 included 15 premenopausal patients with delayed imaging 3 hours after injection. Ten of them showed endometrial uptake, and 8 showed intense uptake in 10 ovaries. Visual and semiquantitative methods were applied for analysis.

RESULTS

By analysis of serial PET studies, endometrial and ovarian uptake showed some specific characteristics. Surrounded by a relatively low-uptake uterine wall, the inverted cone-shaped endometrium showed 2 peaks of uptake, one in early menstruation and the other in midcycle. The ovarian uptake was more prominent in the midcycle, and the foci of uptake had an ovoid shape and located at the left and/or right side superior-posterior to the bladder. For the postmenopausal and amenorrhea women (35 studies), only one study in a woman within 1 year of menopause showed mild endometrial and ovarian uptake. Compared with the imaging 1 hour after injection, the standardized uptake value increased in 2 of 10 endometria and 4 of 10 ovaries in the delayed imaging.

CONCLUSION

Physiological endometrial and ovarian uptake can be identified on PET alone by their specific shape and position as well as their relation to the menstrual state, whereas delayed imaging was of little value for differentiation in this preliminary study.

Extrathoracic PET/CT Findings in Thoracic Malignancies

The routine use of integrated positron emission tomography computed tomography in the staging and follow-up of patients diagnosed with non-small-cell lung cancer has improved diagnostic accuracy but many incidental extrathoracic findings are routinely encountered. These include physiologic fluorodeoxy glucose avid foci, normal computed tomography variants, and second primary malignancies, all of which have to be differentiated from extrathoracic metastatic disease. Knowledge of these findings is important for correct staging and identification of second primaries.