Node Uptake Research Articles

Therapy Response Assessment and Patient Outcomes in Head and Neck Squamous Cell Carcinoma: FDG PET Hopkins Criteria Versus Residual Neck Node Size and Morphologic Features.

This study investigates the prognostic value of (18)F-FDG PET/CT qualitative therapy assessment (Hopkins criteria) in patients with head and neck squamous cell carcinomas (HNSCCs) with residual neck nodes after definitive chemoradiation therapy and compares the Hopkins criteria with anatomic nodal size and morphologic features for prediction of survival outcomes. A total of 72 patients with HNSCC, with negative primary tumor and positive residual neck nodes (CT criteria > 1 cm short-axis diameter) after the completion of definitive chemoradiation therapy, were included. PET/CT was performed 6-24 weeks after completion of treatment. FDG uptake in residual nodes on PET/CT was interpreted using a structured qualitative 5-point scale (Hopkins criteria). The 5-point scale was dichotomized to negative (scores 1, 2, and 3) or positive (scores 4 and 5) results. Cystic or necrotic nodes were defined as those with central low attenuation with a relatively hyperdense capsule. Kaplan-Meier curve and Cox regression analysis were performed. On the basis of the Hopkins criteria, 10 (13.9%) patients had positive findings and 62 (86.1%) had negative findings for residual nodal disease. According to CT interpretation, 25 patients (34.7%) had residual cervical lymph nodes greater than or equal to 1.5 cm in diameter, and 41 (56.9%) patients had cystic or necrotic nodes. Patients were followed for a median of 27 months after posttherapy PET/CT. There was a statistically significant difference in overall survival (OS) (hazard ratio, 7.06; p < 0.001) and progression-free survival (PFS) (hazard ratio, 6.18; p < 0.001) between patients with negative versus positive residual FDG nodal uptake. There was no statistically significant difference in OS and PFS in patients categorized on the basis of nodal size or morphologic features. PET-based structured qualitative therapy assessment (Hopkins criteria) can predict survival outcomes of patients with HNSCC with residual neck nodes after definitive chemoradiotherapy.

Lymphatic Function in the Early Postoperative Period of Breast Cancer Has No Short-Term Clinical Impact.

To evaluate by lymphoscintigraphy the lymphatic function in the preoperative period up to 2 months after surgery for breast cancer, and the relationship between the lymphatic function with clinical features and physical complications. One hundred and five women were studied before and 2 months after surgery to treat breast cancer. On each occasion, inspection and palpation of surgical wound, upper limb circumference, and lymphoscintigraphy were performed. Lymphatic function analysis consisted of velocity of axillary lymph node (LN) visualization; intensity of LN uptake; collateral circulation; dermal backflow; and hepatic uptake. In the postoperative period, there was a significant worsening of the degree of LN uptake (p = 0.0003) and in the velocity of LN visualization (p = 0.01). No significant differences in dermal backflow (p = 0.4) and collateral circulation (p = 0,07) were observed. There was a significant increase in liver absorption (p = 0.0002). 37.1% of the patients developed seroma, 11.2% dehiscence, and 25.8% infection. No relationship was found between lymphoscintigraphy changes and postoperative complications or clinical characteristics. Lymphoscintigraphy, performed 60 days post surgery for breast cancer, can detect a worsening in lymphatic drainage and some sign of lymphatic changes. These changes are not related to clinical characteristics and physical complications.

Radiopharmaceuticals for SPECT Cancer Detection

The purpose of the study was to assess the efficacy of single photon emission computed tomography (SPECT) with 199Tl and 99mTc-MIBI in the detection of breast, laryngeal and hypopharyngeal cancers. Materials and Methods: a total of 220 patients were included into the study. Of them, there were 120 patients with breast lesions (100 patients with breast cancer and 20 patients with benign breast tumors) and '00 patients with laryngeal/hypopharyngeal diseases (80 patients with laryngeal/hypopharyngeal cancer and 20 patients with benign laryngeal/hypopharyngeal lesions). Results: no abnormal 199Tl uptake was seen in all patients with benign breast and laryngeal lesions, indicating a 100% specificity of 199Tl SPECT. In breast cancer patients, increased 199Tl uptake in the breast was visualized in 94.8% patients, 99mTc-MIBI in 93.4% patients. Increased 199Tl uptake in axillary lymph nodes was detected in 60% patients and 99mTc-MIBI in 93.1% patients. In patients with laryngeal/hypopharyngeal cancer, sensitivity of SPECT with 199Tl and 99mTc-MIBI were 95%. The 199Tl SPECT sensitivity in identification of regional lymph node metastases in patients with laryngeal/hypopharyngeal cancer was 75% and the 99mTc-MIBI SPECT sensitivity was 17%. Conclusion: the data obtained show that SPECT with 199Tl and 99mTc-MIBI can be used as one of the additional imaging methods in detection of tumors.

Integration of (68)Ga-PSMA-PET imaging in planning of primary definitive radiotherapy in prostate cancer: a retrospective study.

BackgroundProstate cancer (PC) is one of the most commonly treated cancer entities with radiation therapy (RT). Risk group-adapted treatment and avoidance of unnecessary toxicities relies primarily on accurate tumor staging. Thus, the introduction of prostate-specific membrane antigen (PSMA) in diagnosis and treatment of PC is a highly interesting development in radiation oncology of urologic tumors. The present work is to evaluate the integration of 68Ga-PSMA-PET imaging into standard radiation planning of primary definitive treatment of PC and to determine the impact of PSMA imaging on tumor staging.MethodsThe data of 15 patients treated for PC between August 2013 and April 2015 were evaluated. Treatment planning included 68Ga-PSMA-PET imaging. We analyzed whether the use of PSMA-imaging led to a change of the TNM stage and if it influenced the RT treatment approach or the target volume, due to changes in the gross tumor volume (GTV) or clinical target volume (CTV), in the final treatment plan.ResultsIn 53.3 % of the analyzed patients a change occurred in the TNM stage based on 68Ga-PSMA-PET examination. The RT concept changed in 33.3 % of all patients, leading to relevant changes in the planning target volume. Among these, an additional irradiation of the pelvic lymph drainage due to tracer uptake in lymph nodes was performed in 25 %. Furthermore, boost volumes of PET-positive lymph nodes were added in 80 % of these cases. A down staging due to the 68Ga-PSMA-PET examination occurred in 13.3 % of all cases.ConclusionsThe integration of 68Ga-PSMA-PET-imaging into the RT treatment planning process can be useful for detailed target volume planning. The performance of a 68Ga-PSMA-PET frequently leads to changes in the TNM stage, altering the RT treatment regimen and the target volume. A prospective trial is underway to evaluate the impact of 68Ga-PSMA-PET based treatment planning on outcome.

A Pilot Study of 18F-FLT PET/CT in Pediatric Lymphoma.

We performed an observational pilot study of 18F-FLT PET/CT in pediatric lymphoma. Eight patients with equivocal 18F-FDG PET/CT underwent imaging with 18F-FLT PET/CT. No immediate adverse reactions to 18F-FLT were observed. Compared to 18F-FDG, 18F-FLT uptake was significantly higher in bone marrow and liver (18F-FLT SUV 8.6 ± 0.6 and 5.0 ± 0.3, versus 18F-FDG SUV 1.9 ± 0.1 and 3.4 ± 0.7, resp., p < 0.05). In total, 15 lesions were evaluated with average 18F-FDG and 18F-FLT SUVs of 2.6 ± 0.1 and 2.0 ± 0.4, respectively. Nonspecific uptake in reactive lymph nodes and thymus was observed. Future studies to assess the clinical utility of 18F-FLT PET/CT in pediatric lymphoma are planned.

Clinical significance of post-treatment 18F-fluorodeoxyglucose uptake in cervical lymph nodes in patients with diffuse large B-cell lymphoma.

We assessed the clinical significance of FDG uptake in cervical lymph nodes after treatment of patients with DLBCL. In total, 87 patients with DLBCL were enrolled. All patients had newly appeared FDG uptake in cervical lymph nodes on PET/CT during follow-up after cessation of therapy. Cervical lymph nodes were finally diagnosed as benign or malignant according to histopathological findings or follow-up PET. Clinical characteristics and PET findings were compared between groups and factors associated with malignant lesions were evaluated. Only 8 (9.2%) patients with cervical lymph nodes with FDG uptake ultimately had malignancy. FDG uptake lymph nodes appeared significantly earlier in the malignant group than in patients with benign FDG uptake (p = 0.013). Primary nodal lymphoma was more frequent in patients with cancer spread than in those with benign FDG uptake in lymph nodes (p < 0.001). Most cervical lymph nodes with FDG uptake (about 91%) appearing after treatment of malignant DLBCL were ultimately benign. The elapsed time between the end of therapy and the appearance of cervical lymph nodes with FDG uptake and the primary sites of lymphomas are helpful clues in determining which cases are malignant. • About 91 % appearing after treatment of DLBCL were benign. • Elapsed time between therapy and FDG uptake was associated with malignancy. • Primary sites of lymphoma are helpful clues to determine malignancy.

Standardized visual reading of F18-FDG-PET in patients with non-small cell lung cancer scheduled for preoperative thoracic lymph node staging

ObjectivesRoutine visual assessment of positron emission tomography (PET) for thoracic lymph node (LN) staging in patients with non-small cell lung cancer (NSCLC) is limited by a lack of reliable assessment criteria. This study evaluates the accuracy and inter-rater agreement of a standardized approach with unified windowing and a PET-based visual score. Materials and methodsThis retrospective analysis included pretherapeutic FDG-PET data of 86 patients with NSCLC. After standardized windowing (threshold: 2×liver SUVmean) the LN uptake was assessed visually by three independent readers with varying levels of experience using a 4-step score (1, LN uptake≤mediastinal blood pool structures (MBPS); 2, MBPS<LN<liver; 3, liver≤LN<‘black’; 4, LN appears ‘black’). ROC analyses and respective areas under the curve (AUC) based on histology/cytology as standard of reference. Agreement was analyzed with Cohen’s kappa (κ, pairwise) and Fleiss’ κ (overall). Subgroup analyses separated between hilar vs. mediastinal LNs, adenocarcinoma vs. squamous cell carcinoma and grading G1/2 vs. G3/4. ResultsFifty-four of the 278LNs (19.4%) were malignant (optimal cut-off to differentiate benign vs. malignant, score >3). The inexperienced (n=1), advanced (n=1), and expert readers (n=1) achieved similar accuracies of 93.5%, 91.4% and 92.1%, respectively (P>0.05 each). Cohen’s κ ranged from 0.92 to 0.96 and Fleiss’ κ was 0.93. ROC-analyses showed no significant differences between attendant readers within any subgroup (AUC, 0.92–0.96). ConclusionApplying unified windowing, the introduced PET-score achieved highly accurate and robust LN assessment. This approach may shorten learning curves of inexperienced readers, facilitate multicenter trials, and improve comparability of future studies.

PET-CT for Evaluation of Spleen and Liver 18F-FDG Diffuse Uptake Without Lymph Node Enlargement in Lymphoma.

The aim of the study was to compare differences between lymphoma and inflammation as indicated by high diffuse uptake of 18F-fluorodeoxyglucose (18F-FDG) in the spleen, liver, and bone marrow without increased 18F-FDG uptake in the lymph nodes and without enlarged peripheral lymph nodes.Eighteen lymphoma patients and 14 inflammation patients were examined with 18F-FDG positron emission tomography–computer tomography (PET-CT). All patients displayed high diffuse uptake of 18F-FDG in the spleen, liver, and bone marrow without increased 18F-FDG uptake in the lymph nodes and without enlarged peripheral lymph nodes. Our analyses compared the maximum standardized uptake values (SUVmax) of 18F-FDG uptake ratios between the spleen/liver, the spleen/bone marrow, and the liver/bone marrow and further compared spleen sizes between lymphoma and inflammation patients.Using Student t test, no significant differences were found in the SUVmax ratios of spleen/liver and liver/bone marrow between the lymphoma and inflammation patients (t = 0.853, P = 0.401 > 0.05; t = 1.622, P = 0.115 > 0.05). However, the SUVmax ratio of the spleen/bone marrow of the lymphoma patients was significantly different from that of the inflammation patients (t = 2.426, P = 0.021 < 0.05). The spleen size between the lymphoma and inflammation patients was also significantly different (t = 2.911, P = 0.007 < 0.05).As indicated by 18F-FDG PET-CT, our study demonstrated that lymphoma and inflammation patients displayed a few differences despite both having high diffuse uptake of 18F-FDG in the spleen, liver, and bone marrow without enlarged peripheral lymph nodes and without increased 18F-FDG uptake in lymph nodes.

Magnetic sentinel lymph node biopsy in a murine tumour model

The magnetic technique for sentinel node biopsy provides a radioisotope-free alternative for staging breast cancer. It requires refinement to reduce “residual iron content” at injection sites by maximising lymphatic uptake to prevent “void artefacts” on magnetic resonance imaging (MRI), which could adversely affect clinical use. The site and timing of injection of magnetic tracer was evaluated in a murine tumour model (right hind limb) in 24 wild type mice. Right-sided intratumoural and left sided subcutaneous injection of magnetic tracer and assessment of nodal iron uptake on MRI, surgical excision and histopathological grading at time frames up to 24 hours were performed. Rapid iron uptake on MRI, smaller “void artefacts”(P < 0.001) and a significant increase in iron content with time were identified in the subcutaneous injection group (r = 0.937; P < 0.001).Subcutaneous injection and increasing delay between tracer injection and surgery is beneficial for lymphatic iron uptake.

Biodistribution of [(68)Ga]PSMA-HBED-CC in Patients with Prostate Cancer: Characterization of Uptake in Normal Organs and Tumour Lesions.

The aim of this study was to determine the physiological and pathophysiological biodistribution of [(68)Ga]PSMA-HBED-CC (PSMA-11) ([(68)Ga]PSMA) in patients with prostate cancer (PCA) to establish the range of normal uptake in relevant organs and primary prostate tumours, locally recurrent PCA, lymph and bone metastases and other metastatic lesions. Additionally, we aimed to determine a cut-off uptake value for differentiation of primary tumours from normal prostate tissue. Overall, [(68)Ga]PSMA positron emission tomography/x-ray computed tomography (PET/CT) of 101 patients (mean age 69.1years) with PCA was analysed retrospectively. For assessment of tracer biodistribution, maximum standardized uptake values (SUVmax) were calculated for various normal organs, as well as for primary tumours (PT) and/or metastases. Results are presented as median, interquartile range (IQR; 25th quantil-75th quantil) and range (minimum-maximum). [(68)Ga]PSMA PET/CT was performed 50min (range 30-126) after injection of 109MBq (range 84-158). Regarding biodistribution, highest uptake (median/IQR/range) of the tracer was found in the kidneys (49.6/40.7-57.6/2.7-97.0) followed by the submandibular glands (17.3/13.7-21.2/7.5-30.4), parotid glands (16.1/12.2-19.8/5.5-30.9) and duodenum (13.8/10.5-17.2/5.8-26.9). The best cut-off value for differentiating physiological uptake in the primary tumour from that in the prostate was found to be an SUVmax of 3.2. The median SUVmax in the PT (n = 35), locally recurrent PCA (n = 8), lymph node (n = 166), bone (n = 157) and other metastases (n = 3) were 10.2, 5.9, 6.2, 7.4 and 3.8, respectively. The best cut-off values for differentiating non-pathological uptake in lymph nodes and bones from tumour uptake were found to be SUVmax of 3.2 and 1.9, respectively. Patients with PSA <2 had significantly lower SUVmax in bone metastases as compared to patients with PSA ≥2 (p < 0.01). This biodistribution study provided a broad range of uptake data of [(68)Ga]PSMA-11 for normal organs/tissues, primary prostate tumours and metastatic lesions based on a large patient cohort. Both PT and small metastatic lesions were detectable due to their high tracer uptake. Four-times-higher median uptake in PT in comparison to normal prostate stroma resulted in a high diagnostic accuracy that could potentially be used for multimodal image-guided biopsy with dedicated reconstruction software.

Biodistribution and Lymphatic Tracking of the Main Neurotoxin of Micrurus fulvius Venom by Molecular Imaging.

The venom of the Eastern coral snake Micrurus fulvius can cause respiratory paralysis in the bitten patient, which is attributable to β-neurotoxins (β-NTx). The aim of this work was to study the biodistribution and lymphatic tracking by molecular imaging of the main β-NTx of M. fulvius venom. β-NTx was bioconjugated with the chelator diethylenetriaminepenta-acetic acid (DTPA) and radiolabeled with the radionuclide Gallium-67. Radiolabeling efficiency was 60%–78%; radiochemical purity ≥92%; and stability at 48 h ≥ 85%. The median lethal dose (LD50) and PLA2 activity of bioconjugated β-NTx decreased 3 and 2.5 times, respectively, in comparison with native β-NTx. The immune recognition by polyclonal antibodies decreased 10 times. Biodistribution of β-NTx-DTPA-67Ga in rats showed increased uptake in popliteal, lumbar nodes and kidneys that was not observed with 67Ga-free. Accumulation in organs at 24 h was less than 1%, except for kidneys, where the average was 3.7%. The inoculation site works as a depot, since 10% of the initial dose of β-NTx-DTPA-67Ga remains there for up to 48 h. This work clearly demonstrates the lymphatic system participation in the biodistribution of β-NTx-DTPA-67Ga. Our approach could be applied to analyze the role of the lymphatic system in snakebite for a better understanding of envenoming.

(18)F-FDG PET/CT imaging in systemic lupus erythematosus related autoimmune haemolytic anaemia and lymphadenopathy.

We present a case of systemic lupus erythematosus (SLE) related autoimmune haemolytic anaemia (AIHA) and lymphadenopathy. AIHA as a serious complication of SLE, requiring urgent appropriate management. The timely differential diagnosis between SLE with lymphadenopathy and lymphoma, primary and SLE-related AIHA often looms as practical challenge under clinical scenario. Fluorine-18 fluorodeoxyglucose position emission tomography/computed tomography ((18)F-FDG PET/CT) performed for fever of a known origin and for possible malignancy, showed increased (18)F-FDG uptake in lymph nodes, as well as increased spleen uptake, which was probably due to lymphoma. A symmetrically increased (18)F-FDG uptake in small lymph nodes with multiple serous cavity effusion helped the differential diagnosis between SLE related AIHA and lymphoma. In addition, PET/CT can visualize not only the degree of disease activity or the "burden of inflammation" but also the distribution of the disease in the entire body.

Rare Presentation of Richter’s Transformation to Diffuse Large B Cell Lymphoma: a Case Report

Richter’s syndrome refers to the development of aggressive lymphoma in a patient with chronic lymphocytic leukemia (CLL). It occurs in about 2% to 10% of patients with CLL. The most frequent manifestation of Richter’s syndrome is diffuse large B cell lymphoma (DLBCL). Extranodal involvement is rare but can occur. The prognosis of Richter’s syndrome is very poor. We herein report a case of a rare presentation of Richter’s syndrome. A 42-year-old man diagnosed with CLL 2 years previously developed nodules on the bilateral thighs and buttocks. A positron emission tomography (PET)-CT scan revealed high fluorodeoxyglucose uptake in multiple lymph nodes, skeletal muscles, and the myocardium. An ultrasonography-guided biopsy confirmed Richter’s syndrome from CLL to DLBCL. The patient was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy. After six cycles of chemotherapy, we performed a PET-CT scan that revealed a complete response. However, 3 months later, the syndrome recurred. The patient was undergoing salvage chemotherapy at the time of this writing. (Korean J Med 2016;90:163-168)

Detection of prostate cancer with the [68Ga]-labeled bombesin antagonist RM2 in patients undergoing radical prostatectomy.

80 Background: Gastrin-releasing-peptide receptor (GRPr) is overexpressed in prostate carcinoma (PCa) and offer new means to detect prostate cancer. The bombesin derivative RM2 (DOTA-4-amino-1-carboxymethylpiperidine-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2) is a GRPr antagonist with high binding affinity (Kd 3 nM). A first-in-man study was performed to assess tumor targeting potential of [68Ga]RM2 in patients with local PCa using PET/CT. Based on promising results a Phase I/II study in local PCa was initiated. Methods: In the initial study eleven men with biopsy-proven PCa scheduled for radical prostatectomy were enrolled. The patients (pt) received an i.v. dose of 140 MBq of [68Ga]RM2 followed by dynamic imaging for at least 60 min p.i. The PET assessment included visual evaluation of [68Ga]RM2 intra-prostatic and nodal uptake as well as quantification. An ongoing Phase I/II study is designed to enroll 30+50 biopsy-positive PCa patients. The initial 30 pt have been enrolled, stratified into high, intermediate and low risk of prostate Ca recurrence as defined by NCCN criteria. Results: High uptake of [68Ga]RM2 is seen in pancreas and the urinary system with low background in the rest of the body. Despite of high bladder activity focal or multifocal intraprostatic uptake was detectable. In the first study 10 of 11 pt had positive scans. Subsector analysis of PET positivity vs. pathology yielded a sensitivity, specificity and accuracy of 89, 81, and 83%, respectively. SUVmax was measured in 14 lesions from 9 pts, classified in two groups according to postoperative Gleason score (GS). The higher GS group showed a trend toward higher SUV-values, 10.0 ± 6.7 vs. 6.2 ± 2.5 (t-test: t = -1.21, p-value = 0.28). Both of which were elevated compared to normal tissue 1.2 ± 0.8 The ongoing study is designed with a power of 95% to discriminate between the two GS groups with statistical significance (p = 0.05). Conclusions: [68Ga]RM2 is a promising new tracer with a high detection rate for PCa. Preliminary data indicates higher uptake in more aggressive cancers. The current study is assessing the diagnostic accuracy and impact of presurgical risk assessment on tumor detection in newly diagnosed PCa patients. Clinical trial information: NCT02483884.

Sentinel lymph node scintigraphy in cutaneous melanoma using a planar calibration phantom filled with Tc-99m pertechnetate solution for body contouring.

Background and aimsMelanoma is a disease that has an increasing incidence worldwide. Sentinel lymph node scintigraphy is a diagnostic tool that offers important information regarding the localization of the sentinel lymph nodes offering important input data to establish a pertinent and personalized therapeutic strategy. The golden standard in body contouring for sentinel lymph node scintigraphy is to use a planar flood source of Cobalt-57 (Co-57) placed behind the patients, against the gamma camera. The purpose of the study was to determine the performance of the procedure using a flood calibration planar phantom filled with aqueous solution of Technetion-99m (Tc-99m) in comparison with the published data in literature where the gold standard was used.MethodsThe study was conducted in the Department of Nuclear Medicine of Oncology Institute “Prof. Dr. Ion Chiricuţă” Cluj-Napoca in 95 patients, 31 males and 64 females. The localization of the lesions was grouped by anatomical regions as follows: 23 on lower limbs, 17 on upper limbs, 45 on thorax and 10 on abdomen. The calibration flood phantom containing aqueous solution of Tc-99m pertechnetate was used as planar source to visualize the body contour of the patients for a proper anatomic localization of detected sentinel lymph nodes. The radiopharmaceutical uptake in sentinel lymph nodes has been recorded in serial images following peritumoral injection of 1 ml solution of Tc-99m albumin nanocolloids with an activity of 1 mCi (37 MBq). The used protocol consisted in early acquired planar images within 15 minutes post-injection and delayed images at 2–3 hours and when necessary, additional images at 6–7 hours. The acquisition matrix used was 128×128 pixels for an acquisition time of 5 – 7 minutes. The skin projection of the sentinel lymph nodes was marked on the skin and surgical removal of detected sentinel lymph nodes was performed the next day using a gamma probe for detection and measurements.ResultsThe sentinel lymph nodes were detected in 92 cases and confirmed with the gamma probe during the surgical procedure. The localization of the lymph nodes was as follows: for the tumors localized on lower limb 23 lymph nodes were localized in inguinal region, for the tumors localized on upper limb, 17 lymph nodes were localized in axilla, for the tumors localized on the thorax, 40 lymph nodes were localized in axilla and 3 were localized in the inguinal region; for the tumors localized on the abdomen, 1 lymph node was localized in axilla and 8 lymph nodes was localized in inguinal region. Regarding the negative sentinel lymph node cases, 2 cases were registered for primarily lesions localized on thorax and 1 for a lesion localized on abdomen. According to histology, 26 cases revealed lymphatic metastatic invasion. Dose rates measured at 1m from the calibrator phantom had an average value of 3.46 μSv/h (SD 0.19) and at 1.4m, the value was 2.57 μSv/h (SD 0.22). Dose rates measured at the same distances from the Co-57 planar flood source had a average values of 32.5μSv/h (SD 0.11) respectively 24.1 μSv/h (SD 0.14).ConclusionThe planar calibration flood phantom is an effective tool for body contouring in sentinel lymph node scintigraphy and offers accurate anatomical information to efficiently localize the detected sentinel lymph nodes in melanoma, being for the first time used and mentioned as a pertinent alternative in our department.

Magnetic sentinel lymph node biopsy in a murine tumour model

The magnetic technique for sentinel node biopsy provides a radioisotope-free alternative for staging breast cancer. It requires refinement to reduce “residual iron content” at injection sites by maximising lymphatic uptake to prevent “void artefacts” on magnetic resonance imaging (MRI), which could adversely affect clinical use. The site and timing of injection of magnetic tracer was evaluated in a murine tumour model (right hind limb) in 24 wild type mice. Right-sided intratumoural and left sided subcutaneous injection of magnetic tracer and assessment of nodal iron uptake on MRI, surgical excision and histopathological grading at time frames up to 24 hours were performed. Rapid iron uptake on MRI, smaller “void artefacts”(P<0.001) and a significant increase in iron content with time were identified in the subcutaneous injection group (r=0.937; P<0.001).Subcutaneous injection and increasing delay between tracer injection and surgery is beneficial for lymphatic iron uptake. From the Clinical EditorSentinel lymph node biopsy (SLNB) has been the standard of care in breast cancer management for some time. Recent development has seen the introduction of magnetic tracer for SLNB. In this article, the authors investigated the refined use of magnetic tracer in determining the optimal timing of administration and the location of injection. The findings should provide more data on the future use of this new technique.

Systemic Immune Response to Vaccination on FDG-PET/CT.

A patient with newly diagnosed right lung cancer had transient 18F-fluorodeoxyglucose (FDG)-avid left axillary lymph nodes and intense splenic FDG uptake on positron emission tomography (PET)/computed tomography (CT). History revealed that the patient received a left-sided influenza vaccine 2-3 days before the examination. Although inflammatory FDG uptake in ipsilateral axillary nodes is reported, to our knowledge, this is the first report of visualization of the systemic immune response in the spleen related to the influenza vaccination on FDG-PET/CT. The history, splenic uptake and time course on serial FDG-PET/CT helped to avoid a false-positive interpretation for progressing lung cancer and alteration of the radiation therapy plan.

Visual Vignette

Case presentation: A 38-year-old male was admitted with a 4-year history of paroxysmal headache, erectile dysfunction, and fatigue. He also reported dizziness, generalized muscle aches, and weakness. On physical examination, the patient was afebrile. His heart rate and blood pressure were 95 beats per minute and 90/50 mm Hg. respectively. The sodium level was 171 mmol/L, potassium level 3.5 mmol/L, chloride level 135 mmol/L, plasma osmotic pressure 339 mOsm/kgH2O, and urine osmotic pressure 362 mOsm/kgH2O. A pituitary function assessment revealed secondary hypocortisolism and hypogonadotropic hypogonadism. A visual field examination showed no significant abnormalities. Pituitary magnetic resonance imaging (MRI) revealed a large mass in the hypothalamic area and right posterior horn of lateral ventricle with thickening of the pituitary stalk, which was about 6 mm (Fig. 1). Whole-body positron emission tomography-computed tomography using 18F-fluorodexoyglucose showed mild lymph node uptake (Fig. 2 involving the neck, mediastinum, right armpit, supratrochlear area, and groin bilaterally). His erythrocyte sedimentation rate and high-sensitivity C-reactive protein and serum angiotensin-converting enzyme (sACE) levels were in normal ranges. Left inguinal lymph node biopsy revealed epithelioid granulomas. What is the diagnosis?

FDG PET/CT for assessing the resectability of NSCLC patients with N2 disease after neoadjuvant therapy.

Neoadjuvant chemoradiotherapy (CMRT) is the most effective treatment of stage III non-small-cell lung cancer (NSCLC). The present study aimed at assessing FDG PET/CT for defining the response of N2 disease to neoadjuvant CMRT, as surgical resection after such therapy significantly improves 5-year survival in responding N2 disease. Forty-five patients with locally advanced NSCLC underwent both pre-neoadjuvant therapy FDG PET/CT and post-neoadjuvant therapy FDG PET/CT followed by anatomical resection of lung and ipsilateral mediastinal lymph nodes (LN). Seventeen of these patients who had PET/CT studies in our institution and were operated after CMRT were retrospectively included in the study group (12 males, ages 43-78 years; stage IIIA: 14 patients, stage IIIB: 3 patients). PET/CT response in N2 was visually scored per-lymph node station and per patient. Quantitative N2 response was evaluated by SUVmax and total lesion glycolysis (TLG) measurements after therapy alone and in comparison with pre-therapy values. PET/CT N2 response was confirmed at surgery. Seventeen NSCLC patients with 29 metastatic N2 lymph nodes (LN) were assessed. Histopathology confirmed 14 responders and 3 non-responders, and was available in 20/29 metastatic LN, showing complete response in 17 and residual disease in 3 LN. LN-based visual analysis of N2 response on PET/CT defined 3 TP, 16 TN and 1 FP, for sensitivity, specificity, accuracy, negative and positive predictive values (NPV and PPV) of 100, 94, 95, 100 and 75%, respectively. Patient-based visual analysis defined 3 TP, 13 TN and 1 FP study, for sensitivity, specificity, accuracy, NPV and PPV of 100, 93, 94, 100 and 75%, respectively. Nodal-based quantitative analysis of FDG uptake in N2 nodes revealed a significant difference between responding and non-responding LN only of SUVmax post-therapy (2.5 ± 1.21 vs. 3.5 ± 2.36, P = 0.04). FDG PET/CT after neoadjuvant therapy accurately defined response in metastatic N2 nodes of NSCLC patients, presenting very high sensitivity and NPV for detecting responding nodes. PET/CT may enable selection of candidates for curative resection of stage III NSCLC. Mediastinoscopy may not be mandatory in patients with a negative PET/CT after neoadjuvant therapy.

Dexamethasone Suppression FDG PET/CT for Differentiating between True- and False-Positive Pulmonary and Mediastinal Lymph Node Metastases in Non-Small Cell Lung Cancer: A Pilot Study of FDG PET/CT after Oral Administration of Dexamethasone.

To examine whether dexamethasone suppression can reduce fluorine 18 fluorodeoxyglucose (FDG) uptake in false-positive (FP) findings in pulmonary and mediastinal lymph nodes in non-small cell lung cancer (NSCLC). Institutional ethics review board approved this prospective study with written informed consent. The study population was composed of 17 patients with NSCLC who underwent both baseline and dexamethasone suppression (24 hours after oral administration of 8 mg dexamethasone) FDG positron emission tomography/computed tomography and surgery. FDG uptake was evaluated by using a five-point visual scoring system (negative findings, score of 0-1; positive findings, score of 2-4) and maximum standardized uptake value (SUVmax). The Mann-Whitney U, Wilcoxon signed-rank, Kruskal-Wallis, or Spearman rank correlation tests were used as necessary for statistical evaluations. In 17 primary lesions, no significant difference was noted in visual score between baseline (mean, 3.4 ± 1.2) and dexamethasone suppression scans (mean, 3.3 ± 1.2; P = .16), although SUVmax was significantly lower on dexamethasone suppression scans (mean, 7.1 ± 5.2) than on baseline scans (mean, 8.6 ± 6.6; P = .005). In eight nodes with true-positive (TP) findings, there were no significant differences in visual score (mean for both, 3.8 ± 0.5) and SUVmax (mean, 5.3 ± 2.3 vs 5.5 ± 2.5, respectively; P = .81) between baseline and dexamethasone suppression scans. In 19 nodes with FP findings at baseline, dexamethasone suppression resulted in significantly lowered visual score (mean, 3.4 ± 0.6 vs 2.4 ± 0.8, respectively; P < .001) and SUVmax (mean, 3.5 ± 0.8 vs 2.7 ± 0.7, respectively; P < .001), and four nodes with FP findings were rated as true-negative findings on dexamethasone suppression scans, which resulted in a significant difference in SUVmax between nodal lesions with TP and FP findings (P = .014). Oral dexamethasone has the potential to reduce FDG uptake in pulmonary and mediastinal nodes with FP findings in NSCLC.