FDG-PET/CT is a pivotal imaging modality to diagnose rare intravascular large B-cell lymphoma: case report and review of literature.

Intravascular large B-cell lymphoma (IVLBCL) remains a diagnostic challenge, because of non-specific findings on clinical, laboratory, and imaging studies. We present a case in which 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography was particularly useful to suspect the diagnosis, to detect unexpected locations, to guide contributive biopsy, and to assess the response to treatment. In case of initial negative results, FDG-PET should be repeated in the course of clinical evolution. In the presence of neurological or hormonal symptoms without brain magnetic resonance imaging abnormality, FDG-PET brain slices could depict additional pituitary and/or brain hypermetabolisms. We discuss the potential interests of FDG-PET in IVLBCL by a literature review.

Clinical value of a high-fat and low-carbohydrate diet before FDG-PET/CT for evaluation of patients with suspected cardiac sarcoidosis.

BACKGROUND: We hypothesized that a high-fat and low-carbohydrate (HFLC) diet before FDG-PET/CT could identify patients with active cardiac sarcoidosis (CS). METHODS: Fifty-eight sarcoidosis patients with a suspicion of CS consumed a HFLC diet before FDG-PET/CT. Clinical, electrical, and other imaging investigations were compared to PET results. RESULTS: Using Japanese Ministry of Health and Welfare (JMHW) criteria as a gold standard, 21% (12/58) of patients had a CS. Sensitivity and specificity of PET (visual analysis) were 83% (10/12) and 78% (36/46), respectively, with a very good interobserver agreement (k = 0.86). 70% (7/10) of the patients with a positive PET and negative JMHW criteria exhibited abnormalities suggestive of CS either on MR (n = 3) or SPECT (n = 4). Comparison with the presence of delayed enhancement on magnetic resonance imaging helped to classify patients with active (PET positive) or non-active CS (PET negative). In addition, when MR and PET were both negative, none of the patients met the JMHW criteria. PET response under treatment was concordant with clinical evolution in 11/13 patients. CONCLUSIONS: FDG-PET/CT after HFLC diet is a sensitive tool for the diagnosis of active CS. Combined use of PET and MR is promising for the detection and characterization of CS lesions.

"Real-world" evaluation of 18F-Choline PET/CT practices in prostate cancer patients and impact on changes in therapeutic strategy.

OBJECTIVES: The role of 18F-fluorocholine positron emission tomography/computed tomography (18F-Choline PET/CT) in different clinical situations remains controversial and current practices are very heterogeneous. The aim of this study was to evaluate the "real-world" practice of 18F-Choline PET/CT in patients with prostate cancer and its potential impacts on therapeutic strategy. METHODS AND MATERIALS: This is a retrospective multicenter observational study including 265 consecutive men who underwent 18F-Choline PET/CT for prostate cancer between November 2014 and November 2015. Primary outcome was impact on therapeutic strategy. Secondary outcomes were sensitivity of the 18F-Choline PET/CT and predictive factors associated with positive scans. Statistical analyses comprised Student's t test for continuous variables or chi-squared test for qualitative variables. RESULTS: Median PSA level at the time of PET/CT was 4.19 ng/ml. The decision to perform PET/CT was made after multidisciplinary discussion in 29.8% of cases; most were prescribed by urologists (50.2% of cases). Three main indications were concerned: biochemical recurrence after local treatment (61.1%), initial staging (26.0%), or at the time of progression to castration-resistance (12.9%). Upon biochemical recurrence, 18F-Choline PET/CT allowed identification of ≥1 site(s) with a sensitivity of 80.9%. In multivariate analysis, predictive factors associated with 18F-Choline PET/CT sensitivity were serum PSA level and local treatment type in cases of biochemical recurrence, and PSA doubling time and Gleason score in case of initial staging. 18F-Choline PET/CT results allowed restaging and change in therapeutic strategy in 58.1% of all combined indications. CONCLUSIONS: Indications of 18F-Choline PET/CT were varied. The detection rate of metastatic lesions was suitable, especially when PSA rate was >1 ng/mL. In most cases, 18F-Choline PET/CT led to a change in therapeutic strategy, particularly in the setting of biochemical recurrence.

Clinical improvement and survival in breast cancer leptomeningeal metastasis correlate with the cytologic response to intrathecal chemotherapy.

Leptomeningeal meningitis occurs in approximately 5% of metastatic breast cancers, and there is no standard treatment for this complication. We retrospectively analyzed the clinical data and cerebrospinal fluid of 24 patients treated with high-dose intrathecal methotrexate for breast cancer leptomeningeal meningitis (BLM). Cytologic response (CSF cytology without neoplastic cells after treatment) was observed in 11 patients (46%) and related to survival (P = 0.005). In addition, clinical symptoms improved in all 11 patients who had a cytologic response and in 7 patients (54%) without cytologic response (P = 0.02). The predictive value of cytologic response needs further confirmation. Cytologic response could be helpful in the management of intrathecal chemotherapy in patients with BLM.

Assessing Bone Marrow Activity in Patients with Myelofibrosis: Results of a Pilot Study of 18F-FLT PET.

An emerging noninvasive approach to assess tissue proliferation uses the PET tracer 3'-deoxy-3'-18F-fluorothymidine (18F-FLT). To evaluate the diagnostic value of this technique in myelofibrosis, 18F-FLT PET imaging results were compared with bone marrow histology and bone marrow scintigraphy (BMS), the gold standard techniques in this clinical situation. Methods: Fifteen patients with histology-proven myelofibrosis were included consecutively in the study. Tracers' distributions were assessed using a visual grading assessment score of the uptake in the axial skeleton, proximal and distal limbs, liver, and spleen. This visual score was used to define patterns of tracer distribution and to compare the information provided either by PET or by BMS. A semiquantitative analysis with determination of SUVmax in the same localizations was performed for 18F-FLT PET. Results: The histology grade of fibrosis correlated with the SUVmax in the axial skeleton (spine and iliac crests) and proximal limbs. 18F-FLT uptake in these areas was much lower in patients with grade 3 fibrosis than in patients with grade 1 or 2 fibrosis. 18F-FLT PET showed the same distribution of uptake as BMS in 13 of 14 patients (1 patient did not undergo BMS). In 1 patient, 18F-FLT PET clearly showed an intense abnormal splenic uptake, whereas spleen uptake was inconclusive with BMS. Conclusion:18F-FLT PET appears to be a reliable and convenient technique to assess hematopoietic activity in bone marrow. It yields results close to those observed with BMS. In our study population, 18F-FLT uptake in the axial skeleton and proximal limbs assessed by SUVmax correlated with the grade of fibrosis. Thus, 18F-FLT PET may be a useful tool to measure the severity of myelofibrosis, and to monitor noninvasively the patients' status during follow-up. Finally, 18F-FLT PET may be foreseen as an alternative to BMS.

Prognostic Value of Bone Marrow Tracer Uptake Pattern in Baseline PET Scans in Hodgkin Lymphoma: Results from an International Collaborative Study.

PET/CT-ascertained bone marrow involvement (BMI) constitutes the single most important reason for upstaging by PET/CT in Hodgkin lymphoma (HL). However, BMI assessment in PET/CT can be challenging. This study analyzed the clinicopathologic correlations and prognostic meaning of different patterns of bone marrow (BM) 18F-FDG uptake in HL. Methods: One hundred eighty newly diagnosed early unfavorable and advanced-stage HL patients, all scanned at baseline and after 2 adriamycin-bleomycin-vinblastine-dacarbazine (ABVD) courses with 18F-FDG PET, enrolled in 2 international studies aimed at assessing the role of interim PET scanning in HL, were retrospectively included. Patients were treated with ABVD × 4-6 cycles and involved-field radiation when needed, and no treatment adaptation on interim PET scanning was allowed. Two masked reviewers independently reported the scans. Results: Thirty-eight patients (21.1%) had focal lesions (fPET+), 10 of them with a single (unifocal) and 28 with multiple (multifocal) BM lesions. Fifty-three patients (29.4%) had pure strong (>liver) diffuse uptake (dPET+) and 89 (48.4%) showed no or faint (≤liver) BM uptake (nPET+). BM biopsy was positive in 6 of 38 patients (15.7%) for fPET+, in 1 of 53 (1.9%) for dPET+, and in 5 of 89 (5.6%) for nPET+ dPET+ was correlated with younger age, higher frequency of bulky disease, lower hemoglobin levels, higher leukocyte counts, and similar diffuse uptake in the spleen. Patients with pure dPET+ had a 3-y progression-free survival identical to patients without any 18F-FDG uptake (82.9% and 82.2%, respectively, P = 0.918). However, patients with fPET+ (either unifocal or multifocal) had a 3-y progression-free survival significantly inferior to patients with dPET+ and nPET+ (66.7% and 82.5%, respectively, P = 0.03). The κ values for interobserver agreement were 0.84 for focal uptake and 0.78 for diffuse uptake. Conclusion: We confirmed that 18F-FDG PET scanning is a reliable tool for BMI assessment in HL, and BM biopsy is no longer needed for routine staging. Moreover, the interobserver agreement for BMI in this study proved excellent and only focal 18F-FDG BM uptake should be considered as a harbinger of HL.

[Imaging in head and neck cancers]. / Imagerie des cancers ORL.

The head and neck imaging plays a central role at all stages of the management of cancer. Indeed, the image allows the oncology planning, surgery and radiotherapy. It is a multimodal imaging and the advantages and limitations of each technique must be known. Good knowledge of cervical anatomy is a necessary prerequisite for communication with the multidisciplinary committee. The computerised tomodensitometry is the gold standard for the pharyngolarynx. The MRI is the modality of choice for the oral cavity, oropharynx and nasopharynx. Ultrasound allows a comprehensive study of cervical lymph nodes. Functional imaging and nuclear medicine are still under evaluation. However, the literature already allows establishing their usefulness where morphological imaging is limited. The diagnosis of subclinical metastatic lymph nodes, the differentiation between recurrence and post-treatment modifications, monitoring chemotherapy and radiation therapy planning are indications for which new imaging techniques are invaluable.

[State of the art in nuclear imaging for the diagnosis of bone metastases]. / Place de l'imagerie nucléaire et de ses évolutions pour le diagnostic et le suivi des métastases osseuses.

Cancers prone to spread to bone include prostate, lung, kidney, breast and thyroid cancers. While bone scanner has been widely used in the past decades, PET-based imaging modalities are increasingly used. Current modalities of PET imaging of bone metastases include tumor and inflammatory targeting with FDG-PET, bone imaging with NaF-PET, and direct cancer-specific markers such as FDOPA-PET or PET using choline. The cancer-specific metastatic patterns and the relative prognosis conferred by osseous metastases (versus visceral metastases) may determine the need for bone scan, FDG-PET for the detection of bone metastases. Because some cancers have a mixed skeletal and visceral, cocktails PET radiopharmaceuticals may also be discussed in the future. The cancer-specific context and performances of bone scan and PET imaging are discussed.

Diagnosis of synchronous isolated splenic metastasis from lung adenocarcinoma: complementary role of FDG PET/CT and diffusion-weighted MRI.

Isolated splenic metastasis is extremely rare. In this study, we report a case of a 52-year-old man referred for Pancoast Tobias Syndrome by which FDG PET/CT detected an isolated splenic metastasis. Diffusion-weighted MRI confirmed the isolated splenic lesion. A low apparent diffusion coefficient was consistent with a tumor lesion. CT-guided biopsy of both the lesions and histopathologic findings confirmed a lung adenocarcinoma with an isolated splenic metastasis. This case reveals a very rare occurrence of isolated splenic metastases in the context of lung cancer and illustrates the role of multimodality functional imaging for the early detection of uncommon metastasis.

Tracheobronchial FDG uptake in primary amyloidosis detected by PET/CT.

Tracheobronchial amyloidosis is a rare manifestation of the disease and has never been described with FDG PET/CT. In this study, we report a case of a 70-year-old man with increasing dyspnea, a right pleural effusion, a tracheobronchial circumferential wall thickening, and a mediastinal fat infiltration on CT scan. FDG PET/CT revealed intense tracheobronchial uptake associated with mediastinal and intra-abdominal fat uptake. Bronchoscopy and mediastinoscopy with biopsies confirmed the diagnosis of primary amyloidosis and excluded malignancy. FDG PET/CT could be useful for the evaluation of tracheobronchial amyloidosis metabolic activity and follow-up.

Does chemotherapy influence the quantification of SUV when contrast-enhanced CT is used in PET/CT in lymphoma?

PURPOSE: In patients with lymphoma, we investigated the impact of contrast-enhanced CT on PET attenuation correction in lesions and normal tissues, particularly when PET/CT was performed after chemotherapy. METHODS: Fifty patients (51+/-18 years) with Hodgkin's disease (n=17) or non-Hodgkin lymphomas (n=33) were studied before and after chemotherapy. PET/CT scans were performed 60 min after injection of FDG. Iopamiron 300 (iopamidol, 1.5 cc/kg) was injected immediately afterwards, followed 50 s later by a second craniocaudal CT (CT+). PET images were successively reconstructed using the unenhanced CT (PET-) and the CT+ (PET+) for attenuation correction, using iterative reconstruction (4 iterations, 8 subsets, 5 mm post-filtering). HU(mean), SUV(max) and SUV(mean) were measured before and after chemotherapy in ten non-tumoural ROIs [aorta, femur, kidney, lung, iliopsoas muscle, occipital cortex, T12 vertebra, liver, spleen and inferior vena cava (IVC)] and in tumoural lymphadenopathies or malignant tissues (n=397 and 51 VOIs respectively before and after chemotherapy) using a 3D-thresholding method (identical threshold for PET- and PET+). ROIs were defined on the PET- and automatically applied on the unenhanced CT (CT-), the CT+ and the PET+. RESULTS: In the non-tumoural tissues, HU(mean) increased significantly in the CT+ compared with the CT- in the vessels and the highly vascularised organs, and slight increases were observed in the occipital cortex (+11%), the iliopsoas muscle (+6%) and the femur (+3%). SUV(max) increased significantly in the PET+ compared with the PET- in the aorta (+14%), the liver (+10%), the spleen (+10%) and the IVC (+12%). SUV(mean) increased significantly in the PET+ compared with the PET- in the aorta (+15%), the kidney (+13%), the liver (+11%), the spleen (10%) and the IVC (+12%). In the lesions, HU(mean) was not significantly different before and after chemotherapy, whatever the normal region considered. SUV(max) increased significantly after treatment in the T12 vertebra (+12%). SUV(mean) increased significantly after treatment in the T12 vertebra (+13%) and in the liver (+12%). HU(mean) increased significantly in the CT+ compared with the CT- in the lesions (+55%) before chemotherapy. SUV(max) and SUV(mean) increased significantly in the PET+ compared with the PET- in the lesions (+4%) only before chemotherapy. No significant difference was seen in measurements (HU(mean), SUV(max) and SUV(mean)) after chemotherapy. CONCLUSION: Our study demonstrates that use of enhanced CT for attenuation correction has a negligible effect on quantification at staging and after chemotherapy. A "single-shot" enhanced PET/CT may thus be performed in the evaluation of patients with lymphoma at staging, during treatment and at follow-up.