Myocardial imaging with 18F-fluoro-2-deoxyglucose positron emission tomography and magnetic resonance imaging in sarcoidosis

Purpose Despite accumulating reports on the clinical value of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (¹⁸F-FDG PET) and magnetic resonance imaging (MRI) in the assessment of cardiac sarcoidosis, no studies have systematically compared the images of these modalities. Methods Twenty-one consecutive patients with suspected cardiac sarcoidosis underwent cardiac examinations that included ¹⁸F-FDG PET and MRI. The association of ¹⁸F-FDG PET and MRI findings with blood sampling data such as serum angiotensin converting enzyme levels was also evaluated. Results Eight of 21 patients were diagnosed as having cardiac sarcoidosis according to the Japanese Ministry of Health and Welfare Guidelines for Diagnosing Cardiac Sarcoidosis. Sensitivity and specificity for diagnosing cardiac sarcoidosis were 87.5 and 38.5%, respectively, for ¹⁸F-FDG PET, and 75 and 76.9%, respectively, for MRI. When the ¹⁸F-FDG PET and MRI images were compared, 16 of 21 patients showed positive findings in one (n = 8) or both (n = 8) of the two modalities. In eight patients with positive findings on both images, the distribution of the findings differed among all eight cases. The presence of positive findings on ¹⁸F-FDG PET was associated with elevated serum angiotensin-converting enzyme levels; this association was not demonstrated on MRI. Conclusions Both ¹⁸F-FDG PET and MRI provided high sensitivity for diagnosing cardiac sarcoidosis in patients with suspected cardiac involvement, but the specificity of ¹⁸F-FDG PET was not as high as previously reported. The different distributions of the findings in the two modalities suggest the potential of ¹⁸F-FDG PET and MRI in detecting different pathological processes in the heart.     

Detection of metastatic lesions from malignant pheochromocytoma and paraganglioma with diffusion-weighted magnetic resonance imaging: comparison with 18F-FDG positron emission tomography and 123I-MIBG scintigraphy

OBJECTIVE: To investigate the diagnostic features of whole-body diffusion-weighted magnetic resonance imaging (DWI) as compared with 2-[(18)F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) and (123)I-meta-iodo-benzyl guanidine scintigraphy (MIBG) on metastatic lesions of patients with malignant pheochromocytoma or paraganglioma. METHODS: We prospectively studied 11 patients with histologically confirmed pheochromocytoma/paraganglioma and possible metastatic lesions. FDG-PET, MIBG, and DWI examinations were performed within 1 week, and the images were visually interpreted. Abnormal positive uptake either on MIBG or on FDG-PET was considered as metastases. Abnormal high signal intensities on DWI were considered as metastases using conventional T1-and T2-weighted images as reference. RESULTS: FDG-PET and DWI demonstrated metastatic lesions in all 11 patients, but MIBG showed no metastatic lesions in two patients. The numbers of lymph node metastases depicted on FDG-PET, MIBG, and DWI were 19, 6, and 39; bone metastases were 50, 49, and 60; liver metastases were 9, 9, and 15; lung metastases were 5, 7, and 5, respectively. MIBG failed to demonstrate many metastatic lesions, which were demonstrated on FDG-PET or DWI, although two mediastinal lymph node metastases, three lung metastases, and six bone metastases, which were not seen on DWI, were clearly demonstrated on MIBG. DWI showed 15 liver metastases, but 6 of them were not seen on FDG-PET or MIBG. CONCLUSIONS: DWI may be particularly advantageous in depicting lymph node and liver metastases and may have a higher rate of detecting metastatic lesions when compared with MIBG or FDG-PET. The limitations of DWI were possible false-positive finding, and probable lower detectability of mediastinal lymph node and lung metastasis.     

Dual-phase 18F-fluoro-2-deoxy-d-glucose positron emission tomography as a prognostic parameter in patients with pancreatic cancer

Purpose Recently, dual-phase ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) was shown to be useful in the differentiation between malignant and benign pancreatic lesions. The aim of this prospective study was to evaluate the value of dual-phase FDG-PET as a prognostic parameter in patients with pancreatic cancer.Methods Sixty-five consecutive patients with pancreatic cancer underwent dual-phase FDG-PET. Standardised uptake values at 1 h (SUV1) and 2 h (SUV2) following the injection of FDG were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1. The prognostic value of SUV1, SUV2 and RI was analysed, along with the various clinical and biochemical parameters.Results Multivariate analysis showed that only three factors had an independent association with longer patient survival: female gender (p<0.01), TNM stage I–III (p<0.05) and RI>10% (p<0.01). Neither SUV1 nor SUV2 showed any prognostic significance. Combination of tumour stage and RI allowed more accurate prognostic evaluation. Patients at stage I–III with RI>10% survived longer than did patients at the same stage with RI<10% (15.3 vs 11.5 months, p<0.01). Patients at stage IV with RI>10% had an intermediate prognosis, with a median survival of 9.5 months; patients at stage IV with RI<10% showed the worst prognosis, with a median survival of 4.9 months (p<0.05).Conclusion RI calculated with dual-phase FDG-PET can be used not only as a tool for initial diagnosis and staging of pancreatic cancer but also as a strong independent prognostic parameter that can allow accurate identification of those patients who will benefit from intensive anticancer treatment at different stages of the disease.     

18F-fluorodeoxyglucose positron emission tomography in patients with recurrent ovarian cancer: in comparison with vascularity, Ki-67, p53, and histologic grade

The aim of this study was to assess the correlation between 18F-fluorodeoxyglucose positron emission tomography (FDG PET) positivity of tumor recurrence and vascularity, Ki-67, p53, and histologic grade in patients with ovarian cancer. Nineteen patients with recurrent ovarian cancer underwent FDG PET before second-look surgery. Archival paraffin-embedded tissue materials were used to assess histologic grade including architectural pattern, mitotic activity, and nuclear pleomorphism; intratumor microvessel density (MVD); Ki-67; and p53. Univariate analysis was used to evaluate the correlation between FDG PET positivity and each biomarker. Stepwise logistic regression analysis was used to determine the best parameter to explain FDG PET positivity. MVD revealed significant positive correlation with FDG PET positivity (p=0.0341). There was no significant correlation between FDG PET positivity and Ki-67 or p53 (p=0.4040, p=0.6027). Mitotic activity yielded statistically significant positive correlations with FDG PET positivity (p=0.0448) although histologic grade revealed no positive correlation (p=1). Stepwise logistic regression analysis revealed MVD to be the strongest parameter for FDG PET positivity (OR=0.696, 95% CI 0.487–0.993, p=0.0458). In conclusion, FDG PET positivity revealed positive correlation with MVD and mitotic activity. MVD was the strongest parameter in predicting positive tumor recurrence on FDG PET.     

Disease activity and 18F-FDG uptake in organising pneumonia: semi-quantitative evaluation using computed tomography and positron emission tomography

Purpose: The present study was conducted to evaluate whether ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in combination with computed tomography (CT) reflects disease activity in patients with organising pneumonia.Methods: Eighty-eight subjects who were normal (n=66) or who had proven organising pneumonia (n=22) underwent FDG-PET and CT imaging. The subjects included 55 men and 33 women, ranging in age from 24 to 63 years (mean 47 years). PET and CT data sets were digitally fused using a conformational PET/CT fusion algorithm. All scans were evaluated independently by two chest radiologists who were unaware of other clinical data. The visual score, maximal and mean standardised uptake value (SUV), and maximal and mean lesion-to-normal tissue ratio (LNR) were calculated. The imaging results were compared with the laboratory and pulmonary function test results. The inflammatory cells in the lesions were quantified immunohistochemically.Results: The visual score, maximal and mean SUV, and maximal and mean LNR of the patients with organising pneumonia were significantly higher than those of the normal subjects. The patients with air-space consolidation had a significantly higher SUV than those without air-space consolidation (mean±SD 3.08±0.39 vs 2.35±0.56; p<0.05). The number of CD45⁺ cells was positively correlated with the maximal SUV (r=0.632, p<0.01) and the maximal LNR (r=0.453, p<0.05). The number of CD8⁺ T lymphocytes also showed positive correlations with the maximal SUV (r=0.540, p<0.01) and the maximal LNR (r=0.547, p<0.01).Conclusion: Patients with organising pneumonia have an enhanced FDG accumulation which reflects the degree of disease activity.     

Complementary information from magnetic resonance imaging and (18)F-fluoromisonidazole positron emission tomography in the assessment of the response to an antiangiogenic treatment in a rat brain tumor model

Introduction

No direct proof has been brought to light in a link between hypoxic changes in glioma models and the effects of antiangiogenic treatments. Here, we assessed the sensitivity of the detection of hypoxia through the use of ¹⁸F-fluoromisonidazole positron emission tomography ([¹⁸F]-FMISO PET) in response to the evolution of the tumor and its vasculature.

Methods

Orthotopic glioma tumors were induced in rats after implantation of C6 or 9L cells. Sunitinib was administered from day (D) 17 to D24. At D17 and D24, multiparametric magnetic resonance imaging was performed to characterize tumor growth and vasculature. Hypoxia was assessed by [¹⁸F]-FMISO PET.

Results

We showed that brain hypoxic volumes are related to glioma volume and its vasculature and that an antiangiogenic treatment, leading to an increase in cerebral blood volume and a decrease in vessel permeability, is accompanied by a decrease in the degree of hypoxia.

Conclusions

We propose that [¹⁸F]-FMISO PET and multiparametric magnetic resonance imaging are pertinent complementary tools in the evaluation of the effects of an antiangiogenic treatment in glioma.     

Early restaging whole-body 18F-FDG PET during induction chemotherapy predicts clinical outcome in patients with locoregionally advanced nasopharyngeal carcinoma

Purpose This study was undertaken to evaluate the utility of whole-body ¹⁸F-FDG PET in monitoring therapeutic effect during induction chemotherapy (IC) and in predicting prognosis in patients with locoregionally advanced nasopharyngeal carcinoma (NPC).Methods Fifty patients who had histologically proven, locoregionally advanced NPC without distant metastasis and had received IC were recruited in this study. The study cohort consisted of 19 females and 31 males (age 17–72 years, mean 45.9±11.9). Whole-body ¹⁸F-FDG PET was performed in each patient after completion of one (33 patients) or two (17 patients) courses of IC. Each patient was restaged on the basis of the ¹⁸F-FDG PET results. Patients who were downstaged to stage I or II were classified as major responders; the rest were classified as non-major responders.Results Only 1 of the 23 major responders subsequently developed local recurrence. At the time of data analysis, all major responders were alive; by contrast, of the 27 non-major responders, 15 had locoregional recurrence or distant metastasis and nine had died (seven of NPC and two of treatment-related complications). Kaplan-Meier survival analysis showed significantly longer recurrence-free survival and overall survival in major responders (56.4±9.2 and 58.1±2.2 months) as compared with non-major responders (33.7±23.2 and 44.7±20.0 months), with p<0.0001 and p=0.0024, respectively.Conclusion The results of this study suggest that early restaging by a single whole-body ¹⁸F-FDG PET scan after the first or second course of IC is useful for predicting therapeutic response and outcome in patients with locoregionally advanced NPC.     

Value of (18F)-FDG positron emission tomography, computed tomography, and magnetic resonance imaging in diagnosing primary and recurrent ovarian carcinoma

The aim of this study was to compare prospectively the accuracy of whole-body positron emission tomography (PET), CT and MRI in diagnosing primary and recurrent ovarian cancer. Nineteen patients (age range 23–76 years) were recruited with suspicious ovarian lesions at presentation (n = 8) or follow-up for recurrence (n = 11). All patients were scheduled for laparotomy and histological confirmation. Whole-body PET with FDG, contrast-enhanced spiral CT of the abdomen, including the pelvis, and MRI of the entire abdomen were performed. Each imaging study was evaluated separately. Imaging findings were correlated with histopathological diagnosis. The sensitivity, specificity and accuracy for lesion characterization in patients with suspicious ovarian lesions (n = 7) were, respectively: 100, 67 and 86 % for PET; 100, 67 and 86 % for CT; and 100, 100 and 100 % for MRI. For the diagnosis of recurrent disease (n = 10), PET had a sensitivity of 100 %, specificity of 50 % and accuracy of 90 %. The PET technique was the only technique which correctly identified a single transverse colon metastasis. Results for CT were 40, 50 and 43 %, and for MRI 86, 100 and 89 %, respectively. No statistically significant difference was seen. Neither FDG PET nor CT nor MRI can replace surgery in the detection of microscopic peritoneal disease. No statistically significant difference was observed for the investigated imaging modalities with regard to lesion characterization or detection of recurrent disease; thus, the methods are permissible alternatives. The PET technique, however, has the drawback of less accurate spatial assignment of small lesions compared with CT and MRI. Received: 9 April 1999; Revised: 22 June 1999; Accepted: 25 August 1999     

The value of 18F-DOPA PET-CT in patients with medullary thyroid carcinoma: comparison with 18F-FDG PET-CT

The purpose of this prospective study was to compare the value of DOPA PET-CT with FDG PET-CT in the detection of malignant lesions in patients with medullary thyroid carcinoma (MTC). Twenty-six consecutive patients (10 men, 16 women, mean age 59 ± 14 years) with elevated calcitonin levels were evaluated in this prospective study. DOPA and FDG PET-CT modalities were performed within a maximum of 4 weeks (median 7 days) in all patients. The data were evaluated on a patient- and lesion-based analysis. The final diagnosis of positive PET lesions was based on histopathological findings and/or imaging follow-up studies (i.e., DOPA and/or FDG PET-CT) for at least 6 months (range 6–24 months). In 21 (21/26) patients at least one malignant lesion was detected by DOPA PET, while only 15 (15/26) patients showed abnormal FDG uptake. DOPA PET provided important additional information in the follow-up assessment in seven (27%) patients which changed the therapeutic management. The patient-based analysis of our data demonstrated a sensitivity of 81% for DOPA PET versus 58% for FDG PET, respectively. In four (4/26) postoperative patients DOPA and FDG PET-CT studies were negative in spite of elevated serum calcitonin and CEA levels as well as abnormal pentagastrin tests. Overall 59 pathological lesions with abnormal tracer uptake were seen on DOPA and/or FDG PET studies. In the final diagnosis 53 lesions proved to be malignant. DOPA PET correctly detected 94% (50/53) of malignant lesions, whereas only 62% (33/53) of malignant lesions were detected with FDG PET. DOPA PET-CT showed superior results to FDG PET-CT in the preoperative and follow-up assessment of MTC patients. Therefore, we recommend DOPA PET-CT as a one-stop diagnostic procedure to provide both functional and morphological data in order to select those patients who may benefit from (re-)operation with curative intent as well as guiding further surgical procedures.     

Guidelines for 18F-FDG PET and PET-CT imaging in paediatric oncology

OBJECTIVE: The purpose of these guidelines is to offer to the nuclear medicine team a framework that could prove helpful in daily practice. These guidelines contain information related to the indications, acquisition, processing and interpretation of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) in paediatric oncology. The Oncology Committee of the European Association of Nuclear Medicine (EANM) has published excellent procedure guidelines on tumour imaging with (18)F-FDG PET (Bombardieri et al., Eur J Nucl Med Mol Imaging 30:BP115-24, 2003). These guidelines, published by the EANM Paediatric Committee, do not intend to compete with the existing guidelines, but rather aim at providing additional information on issues particularly relevant to PET imaging of children with cancer. CONCLUSION: The guidelines summarize the views of the Paediatric Committee of the European Association of Nuclear Medicine. They should be taken in the context of "good practice" of nuclear medicine and of any national rules, which may apply to nuclear medicine examinations. The recommendations of these guidelines cannot be applied to all patients in all practice settings. The guidelines should not be deemed inclusive of all proper procedures or exclusive of other procedures reasonably directed to obtaining the same results.     

Staging of untreated nasopharyngeal carcinoma with PET/CT: comparison with conventional imaging work-up

Purpose  We prospectively compared PET/CT and conventional imaging for initial staging of nasopharyngeal carcinoma (NPC). Methods  A total of 111 patients with histologically proven NPC were investigated with PET/CT and conventional imaging (head-and-neck MRI, chest X-ray, abdominal ultrasound, and bone scan) before treatment. The respective findings were reviewed independently and then compared with each other. Results  With regard to T staging, PET/CT showed a discrepancy with head-and-neck MRI in 36 (32.4%) of the study subjects. With regard to N staging, PET/CT showed a discrepancy with head-and-neck MRI in 15 (13.5%) patients. Among the discordant cases, MRI was superior in demonstrating tumor involvement in the parapharyngeal space, skull base, intracranial area, sphenoid sinus, and retropharyngeal nodes while PET/CT was superior in demonstrating neck nodal metastasis. PET/CT disclosed 13 of 16 patients with distant malignancy compared with four patients disclosed by conventional imaging work-up. The false-positive rate of PET/CT was 18.8%. PET/CT correctly modified M staging in eight patients (7.2%) and disclosed a second primary lung malignancy in one patient (0.9%). Conclusion  In NPC patients, MRI appears to be superior to PET/CT for the assessment of locoregional invasion and retropharyngeal nodal metastasis. PET/CT is more accurate than MRI for determining cervical nodal metastasis and should be the better reference for the neck status. PET/CT has an acceptable diagnostic yield and a low false-positive rate for the detection of distant malignancy and can replace conventional work-up to this aim. PET/CT and head-and-neck MRI are suggested for the initial staging of NPC patients. An erratum to this article can be found at     

<Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography in uterine carcinosarcoma

Purpose Uterine carcinosarcomas clinically confined to the uterus usually harbor occult metastases. We conducted a pilot study to evaluate the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in uterine carcinosarcoma. Methods Patients with histologically confirmed uterine carcinosarcoma were enrolled. Abdominal and pelvic magnetic resonance imaging (MRI)/whole-body computed tomography (CT) scan, and whole-body ¹⁸F-FDG PET or PET/CT were undertaken for primary staging, evaluating response, and restaging/post-therapy surveillance. The clinical impact of ¹⁸F-FDG PET was determined on a scan basis. Results A total of 19 patients were recruited and 31 ¹⁸F-FDG PET scans (including 8 scans performed on a PET/CT scanner) were performed. Positive impacts of scans were found in 36.8% (7/19) for primary staging, 66.7% (2/3) for monitoring response, and 11.1% (1/9) for restaging/post-therapy surveillance. PET excluded falsely inoperable disease defined by MRI in two patients. Aggressive treatment applying to three patients with PET-defined resectable stage IVB disease seemed futile. Two patients died of disease shortly after salvage therapy restaged by PET. With PET monitoring, one stage IVB patient treated by targeted therapy only was alive with good performance. Using PET did not lead to improvement of overall survival of this series compared with the historical control (n = 35) (P = 0.779). Conclusions The preliminary results suggest that ¹⁸F-FDG PET is beneficial in excluding falsely inoperable disease for curative therapy and in making a decision on palliation for better quality of life instead of aggressive treatment under the guidance of PET. PET seems to have limited value in post-therapy surveillance or restaging after failure.     

Simultaneous whole body 18F-fluorodeoxyglucose positron emission tomography magnetic resonance imaging for evaluation of pediatric cancer: Preliminary experience and comparison with 18F-fluorodeoxyglucose positron emission tomography computed tomography

AIM: To describe our preliminary experience with simultaneous whole body ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography and magnetic resonance imaging (PET-MRI) in the evaluation of pediatric oncology patients.METHODS: This prospective, observational, single-center study was Health Insurance Portability and Accountability Act-compliant, and institutional review board approved. To be eligible, a patient was required to: (1) have a known or suspected cancer diagnosis; (2) be under the care of a pediatric hematologist/oncologist; and (3) be scheduled for clinically indicated ¹⁸F-FDG positron emission tomography-computed tomography (PET-CT) examination at our institution. Patients underwent PET-CT followed by PET-MRI on the same day. PET-CT examinations were performed using standard department protocols. PET-MRI studies were acquired with an integrated 3 Tesla PET-MRI scanner using whole body T1 Dixon, T2 HASTE, EPI diffusion-weighted imaging (DWI) and STIR sequences. No additional radiotracer was given for the PET-MRI examination. Both PET-CT and PET-MRI examinations were reviewed by consensus by two study personnel. Test performance characteristics of PET-MRI, for the detection of malignant lesions, including FDG maximum standardized uptake value (SUVmax) and minimum apparent diffusion coefficient (ADCmin), were calculated on a per lesion basis using PET-CT as a reference standard.RESULTS: A total of 10 whole body PET-MRI exams were performed in 7 pediatric oncology patients. The mean patient age was 16.1 years (range 12-19 years) including 6 males and 1 female. A total of 20 malignant and 21 benign lesions were identified on PET-CT. PET-MRI SUVmax had excellent correlation with PET-CT SUVmax for both benign and malignant lesions (R = 0.93). PET-MRI SUVmax > 2.5 had 100% accuracy for discriminating benign from malignant lesions using PET-CT reference. Whole body DWI was also evaluated: the mean ADCmin of malignant lesions (780.2 + 326.6) was significantly lower than that of benign lesions (1246.2 + 417.3; P = 0.0003; Student’s t test). A range of ADCmin thresholds for malignancy were evaluated, from 0.5-1.5 × 10^-3 mm²/s. The 1.0 × 10^-3 ADCmin threshold performed best compared with PET-CT reference (68.3% accuracy). However, the accuracy of PET-MRI SUVmax was significantly better than ADCmin for detecting malignant lesions compared with PET-CT reference (P < 0.0001; two-tailed McNemar’s test).CONCLUSION: These results suggest a clinical role for simultaneous whole body PET-MRI in evaluating pediatric cancer patients.     

Analysis of gene expression profiles of hepatocellular carcinomas with regard to 18F-fluorodeoxyglucose uptake pattern on positron emission tomography

Purpose ¹⁸F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan has been found to reflect tumour aggressiveness and prognosis in various types of cancer. In this study, the gene expression profiles of hepatocellular carcinomas (HCCs) were evaluated to determine whether HCCs with high ¹⁸F-FDG uptake have more aggressive biological potential than those with low uptake.Methods Surgical specimens were obtained from ten patients with HCC (six males and four females, age range 38–68 years). The tumour samples were divided into two groups based on the ¹⁸F-FDG PET scan findings: high ¹⁸F-FDG uptake (n=4) and low ¹⁸F-FDG uptake (n=6).Results The pathological tumour grade was closely correlated with the ¹⁸F-FDG uptake pattern: HCCs with high ¹⁸F-FDG uptake were pathologically Edmondson-Steiner grade III, while those with low uptake were either grade II or grade II with a focal area of grade III. The total RNA was extracted from the frozen tissues of all HCCs (n=10) and adjacent non-cancerous tissue (n=7). The gene expression profiles were evaluated using an oligoDNA microarray. The HCCs with high ¹⁸F-FDG uptake showed increased expression of 11 genes—including vascular cell adhesion molecule-1, vinexin beta and core 1 UDP-galactose:N-acetylgalactosamine-alpha-R-beta 1,3-galactosyltransferase and the natural killer cell inhibitory receptor—compared to those with low uptake (p<0.005). Nine genes, including regulator of mitotic spindle assembly 1, grb2-related adaptor protein and beta-1,3-n-acetylglucosaminyltransferase, were repressed.Conclusion Gene expression is closely related to cell survival, cell-to-cell adhesion or cell spreading; therefore, HCCs with high ¹⁸F-FDG uptake appear to have more aggressive biological properties than those with low uptake.     

Usefulness of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography for diagnosing disease activity and monitoring therapeutic response in patients with pulmonary mycobacteriosis

Purpose  To evaluate the usefulness of ¹⁸F-FDG PET in the imaging of pulmonary lesions related to disease activity and in monitoring responses to treatment in patients with pulmonary mycobacteriosis (PM). Materials and methods  We used high-resolution computed tomography (HRCT) and ¹⁸F-FDG PET to evaluate 47 consecutive untreated patients with PM, 25 with tuberculosis (TB) and 22 with Mycobacterium avium-intracellulare complex (MAC), who presented with small peripheral pulmonary nodules ≤3 cm, and compared the findings. The diagnosis of mycobacteriosis was confirmed by bacteriological examinations of bronchoscopic or surgically resected specimens. PET scans were visually and quantitatively analysed using SUVmax. In addition, 14 patients with PM underwent repeat PET scanning during antimycobacterial therapy, and changes in ¹⁸F-FDG uptake were clinically evaluated (6 during treatment and 12 after treatment). Results  Of all the lesions, 87.2% had SUVmax levels ranging from 3 to 7 (5.05 ± 1.56, range 2.5–7.6, n = 47). Further, SUV levels in patients with PM reflected disease activity as estimated by HRCT, but did not differ significantly between those with TB (4.96 ± 1.61, n = 25) and MAC (5.15 ± 1.53, n = 22). ¹⁸F-FDG uptake was significantly decreased in all 14 patients who received chemotherapy, indicating a positive response to treatment. Conclusion   ¹⁸F-FDG PET is considered to be useful for the diagnosis and evaluation of disease activity along with HRCT findings, and in monitoring response to chemotherapy in patients with PM.     

Computed tomography, magnetic resonance imaging and 11C-metomidate positron emission tomography for evaluation of adrenal incidentalomas

Background

Given the higher sensitivity of modern computed tomography (CT) scanners, adrenal incidentalomas are being discovered increasingly often. This implies a growing quantitative diagnostic and clinical problem. CT and/or magnetic resonance imaging (MRI) and usually thorough hormonal testing are routinely used to determine the origin of these lesions. Recently, positron emission tomography (PET) using the tracer ¹¹C-metomidate (MTO) has been established as an alternative diagnostic method with high sensitivity for identifying adrenocortical lesions. The aim of this study was to evaluate the clinical use and value of MTO-PET compared to CT and MRI in the characterisation and work-up of adrenal incidentalomas.

Methods

Initially, we retrospectively evaluated 20 adrenal incidentalomas in patients who had undergone CT, MRI and MTO-PET and from whom we had either histopathological diagnosis or clinical follow-up data. After this analysis we conducted a prospective study in order to compare the imaging modalities. In the latter study, 24 incidentalomas were imaged by CT, MRI and MTO-PET and the results were correlated to those from histopathology (n = 8) and clinical diagnosis after follow-up (n = 16).

Results

In the retrospective analysis, MRI and especially MTO-PET, correlated well to histopathology and clinical diagnosis after follow-up, whereas specificity with CT was low. This was possibly due to the presence of several haematomas/fibrosis which were misdiagnosed as adrenocortical adenomas. In the prospective cohort, sensitivity and specificity with CT were 0.71 and 1.0, respectively, and further characterisation by MRI increased these values to 0.86 and 1.0, whereas maximum sensitivity and specificity were reached when MTO-PET was added.

Conclusion

The diagnosis of an adrenocortical adenoma may be established by CT in most patients and by MRI in an additional number. For the few remaining patients needing further characterisation, MTO-PET is advantageous as an additional imaging modality.     

Opportunities for 2-[18F] Fluoro-2-Deoxy-D-Glucose PET/CT in Cervical-Vaginal Neuroendocrine Carcinoma: Case Series and Literature Review

Objective

Neuroendocrine cervical carcinoma is a rare subtype of cervical cancer. These tumors exhibit an aggressive behavior with early regional lymph node and distant metastases. The purpose of our study was to describe five cases of neuroendocrine cervical-vaginal carcinoma and to discuss the potential of the 2-[¹⁸F] fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) scan for the detection of this rare malignancy.

Materials and Methods

Five cases of cervical-vaginal neuroendocrine tumor were retrospectively collected, during a two year (from September 2009 to August 2011) period in our hospital. The clinical staging distributions were International Federation of Gynecology and Obstetrics (FIGO) stage IB2 (1 of 5), stage IIA (3 of 5) and stage IVA (1 of 5).

Results

Two cases (cases 1 and 4) were restaged after ¹⁸F-FDG PET/CT scan in the initial staging process. Post-treatment ¹⁸F-FDG PET/CT scans, in three patients, revealed positive findings for tumor recurrence or lymph node metastases. Two patients (cases 2 and 3) died of tumor within two years.

Conclusion

¹⁸F-FDG PET/CT scan is a useful tool in cervical-vaginal neuroendocrine tumor. In its initial staging, the ¹⁸F-FDG PET/CT scan may help assess the possible nodal involvement or early hematogeneous spreading. We can also use the ¹⁸F-FDG PET/CT to detect local recurrence and to evaluate the treatment response after clinical manipulation.     

Carbon-11-methionine positron emission tomography imaging of chordoma

Objective Chordoma is a rare malignant bone tumor that arises from notochord remnants. This is the first trial to investigate the utility of ¹¹C-methionine (MET) positron emission tomography (PET) in the imaging of chordoma before and after carbon-ion radiotherapy (CIRT).Design and patients Fifteen patients with chordoma were investigated with MET-PET before and after CIRT and the findings analyzed visually and quantitatively. Tumor MET uptake was evaluated by tumor-to-nontumor ratio (T/N ratio).Results In 12 (80%) patients chordoma was clearly visible in the baseline MET-PET study with a mean T/N ratio of 3.3±1.7. The MET uptake decreased significantly to 2.3±1.4 after CIRT (P<0.05). A significant reduction in tumor MET uptake of 24% was observed after CIRT. Fourteen (93%) patients showed no local recurrence after CIRT with a median follow-up time of 20 months.Conclusion This study has demonstrated that MET-PET is feasible for imaging of chordoma. MET-PET could provide important tumor metabolic information for the therapeutic monitoring of chordoma after CIRT.This study was part of the 10-Year Strategy for Cancer Control of the Japanese Government and was supported by the Ministry of Education, Science and Technology of Japan Government     

Metabolic and vascular features of dynamic contrast-enhanced breast magnetic resonance imaging and (15)O-water positron emission tomography blood flow in breast cancer

RATIONALE AND OBJECTIVES: We sought to (1) describe associations between measures of tumor perfusion by dynamic contrast-enhanced breast magnetic resonance imaging (DCE-MRI), blood flow by (15)O-water positron emission tomography (PET) and metabolism by (18)F-fluorodeoxyglucose ((18)F)-FDG PET and (2) improve our understanding of tumor enhancement on MRI through independent measures of tumor metabolism and blood flow. MATERIALS AND METHODS: We performed a retrospective analysis of the existing PET and MRI databases from the Departments of Nuclear Medicine and Radiology. We identified patients with locally advanced breast cancer who underwent (15)O-water/(18)F-FDG PET within 1 month of clinical DCE-MRI between February 2004 and August 2006. The (15)O-water PET blood flow and (18)F-FDG metabolic rate and tissue transport constant (K(1)) in the primary malignancy were calculated. DCE-MRI peak percent enhancement and peak signal enhancement ratio (SER) were measured for each tumor. Correlations and regression analysis of these variables were performed. RESULTS: Fifteen patients with complete PET and DCE-MRI data were included in the analysis cohort. Peak SER correlated significantly with blood flow (r = 0.73, P = .002) and K(1) (r = 0.76, P = .001). However, peak SER did not correlate significantly with FDG metabolic rate (r = 0.44, P = .101). There were no significant correlations between peak percent enhancement and any of the PET parameters. CONCLUSIONS: Our findings suggest that tumor perfusion, represented by (15)O-water PET blood flow, is an important factor in the MRI enhancement of locally advanced breast cancer. A lack of correlation of FDG metabolic rate with blood flow and DCE-MRI kinetics suggests that (18)F-FDG PET provides complementary metabolic information independent of vascular factors.