Interobserver agreement of qualitative analysis and tumor delineation of 18F-fluoromisonidazole and 3'-deoxy-3'-18F-fluorothymidine PET images in lung cancer

As the preparation phase of a multicenter clinical trial using (18)F-fluoro-2-deoxy-d-glucose ((18)F-FDG), (18)F-fluoromisonidazole ((18)F-FMISO), and 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) in non-small cell lung cancer (NSCLC) patients, we investigated whether 18 nuclear medicine centers would score tracer uptake intensity similarly and define hypoxic and proliferative volumes for 1 patient and we compared different segmentation methods.

METHODS

Ten (18)F-FDG, ten (18)F-FMISO, and ten (18)F-FLT PET/CT examinations were performed before and during curative-intent radiotherapy in 5 patients with NSCLC. The gold standards for uptake intensity and volume delineation were defined by experts. The between-center agreement (18 nuclear medicine departments connected with a dedicated network, SFMN-net [French Society of Nuclear Medicine]) in the scoring of uptake intensity (5-level scale, then divided into 2 levels: 0, normal; 1, abnormal) was quantified by κ-coefficients (κ). The volumes defined by different physicians were compared by overlap and κ. The uptake areas were delineated with 22 different methods of segmentation, based on fixed or adaptive thresholds of standardized uptake value (SUV).

RESULTS

For uptake intensity, the κ values between centers were, respectively, 0.59 for (18)F-FDG, 0.43 for (18)F-FMISO, and 0.44 for (18)F-FLT using the 5-level scale; the values were 0.81 for (18)F-FDG and 0.77 for both (18)F-FMISO and (18)F-FLT using the 2-level scale. The mean overlap and mean κ between observers were 0.13 and 0.19, respectively, for (18)F-FMISO and 0.2 and 0.3, respectively, for (18)F-FLT. The segmentation methods yielded significantly different volumes for (18)F-FMISO and (18)F-FLT (P < 0.001). In comparison with physicians, the best method found was 1.5 × maximum SUV (SUVmax) of the aorta for (18)F-FMISO and 1.3 × SUVmax of the muscle for (18)F-FLT. The methods using the SUV of 1.4 and the method using 1.5 × the SUVmax of the aorta could be used for (18)F-FMISO and (18)F-FLT. Moreover, for (18)F-FLT, 2 other methods (adaptive threshold based on 1.5 or 1.6 × muscle SUVmax) could be used.

CONCLUSION

The reproducibility of the visual analyses of (18)F-FMISO and (18)F-FLT PET/CT images was demonstrated using a 2-level scale across 18 centers, but the interobserver agreement was low for the (18)F-FMISO and (18)F-FLT volume measurements. Our data support the use of a fixed threshold (1.4) or an adaptive threshold using the aorta background to delineate the volume of increased (18)F-FMISO or (18)F-FLT uptake. With respect to the low tumor-on-background ratio of these tracers, we suggest the use of a fixed threshold (1.4).

Sentinel lymph node in prostate carcinoma: Methodology, feasibility, surgical, and oncological consequences: A prospective study about 93 patients

69

Background: There are few studies in the field of prostatic sentinel lymph node (SLN) procedure: in the literature at the most 10 publications are found. However the interest of urological surgeons is growing fast. We want to evaluate the rate of SLN SPECT-CT detection, the rate of SLN involvement, and the incidence of the SLN biopsy on the surgical and oncological management of patients. Methods: 93 patients with prostate cancer were included (gleason 6-9). All patients were elected for a radical laparoscopic prostatectomy. Nanocis* was intratumorally injected, guided by transrectal ultrosonography. 2 injections 0.6 ml in each lobe of the prostate were performed. Patient underwent planar imaging and SPECT-CT 2 hours after injections. Surgery was performed 18 hours after. Results: A lymphatic pelvic drainage was seen in 95,6 % (89/93) by SPECT-CT (external or internal iliac arteries areas). For 27 patients lymphatic drainage was on the right side, for 24 patients it was on the left side, for the 37 remaining patients migration was bilateral. The radioguided lymphadenectomy was assisted by a laparoscopic gamma-probe (Clerad, France), the SLN detection rate was 97.7% (87/89); the average number of resected radioactive nodes was 1.6 (range 1 to 5). By all the ways, a limited pelvic lymph node dissection was performed (including external iliac to common iliac arteries areas) in all 93 cases. An SLN involvement was found in 6 cases (5/87= 5.75%); in these 6 cases and in the 81 cases without SLN involvement, no metastatic involvement was found in the other lymph nodes, as well as in the 6 patients for which no SLN could be selectively resected (4 with no drainage seen and 2 not detected intra-operatively although visualized on lymphoscintigraphy). Conclusions: The low rate of lymphatic involvement is not surprising considering the Gleason score range 6 to 9 (low metastatic risk). So, the preliminary results are very attractive, especially for these patients that could have been falsely considered as N0. Our study is still in progress, and if these results are confirmed on a larger scale, then SLN procedure could be considered in the routine management of low risk prostatic carcinomas.

Sentinel lymph node in prostate carcinoma: Methodology, feasibility, surgical, and oncological consequences, about 74 patients

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Background: There are few studies in the field of prostatic sentinel lymph node (SLN) procedure: in the international literature at the most 10 publications are found. However the interest of urological surgeons and oncologists is growing fast. Goals of our study were: on the first hand to evaluate the rate of SLN SPECT-CT detection and the rate of SLN involvement, on the other hand to evaluate the incidence of the SLN biopsy results on the surgical and oncological management. Methods: 74 patients with prostate cancer were included. All patients had a Gleason score between 6 and 8. All patients were elected for a radical laparoscopic prostatectomy. Nanocis-Tc 99m was intratumorally injected, guided by transrectal ultrosonography. 2 injections of 0.6 ml in each lobe of the prostate were performed, depending on the size of the prostate. Patient underwent planar imaging and SPECT-CT 2 hours after injections. Surgery was performed 18 hours after SPECT-CT lymphoscintigraphy. Results: A lymphatic pelvic drainage was seen in 94,6 % (70/74) by SPECT-CT. Lymphatic drainage was on the right side (23), on the left side (15), or bilateral (32). The radioguided lymphadenectomy was assisted by a laparoscopic gamma-probe, the SLN detection rate was 97% (68/70); the average number of resected radioactive nodes was 1.6 (range 1 to 5). By all the ways, a limited pelvic lymph node dissection was performed in all 74 cases. An SLN involvement was found in 5 cases (5/68= 7.35%); in these 5 cases and in the 63 cases without SLN involvement, no metastatic involvement was found in the other lymph nodes, as well as in the 6 patients for which no SLN could be selectively resected (4 with no drainage seen and 2 not detected intra-operatively although visualized on lymphoscintigraphy). Conclusions: The low rate of lymphatic involvement is not surprising considering the Gleason score range 6 to 8 (low metastatic risk). So, the preliminary results are very attractive, especially for these patients that could have been falsely considered as N0. Our study is still in progress, and if these results are confirmed on a larger scale, then SLN procedure could be considered in the routine management of low risk prostatic carcinomas.

The influence of mammaplasty on axillary lymphatic drainage patterns and sentinel lymph node detection: A 40-patient prospective study including the 20 first patients of the preliminary study

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Background: In the field of sentinel lymph node (SLN) for patients with previously breast surgery, opinions are not definitive. On the first hand, the ASCO in 2005 recommended that SLN biopsy should not be performed in patients with previous mammaplasty or axillary surgery, but, on the other hand, the same panelists of the ASCO guideline suggested that a preliminary lymphoscintigraphy (LSG) could be done when considering a SLN biopsy in patients with previous mammaplasty, with the objective of verifying the integrity of axillary nodes. We started a prospective study in January 2009, to evaluate the location of sentinel lymph node (SLN) before and after mammaplasty. The preliminary results of the first 20 patients were presented in June 2010 (Chicago, ASCO), however it was to be necessary to have more patients to validate these encouraging results. The results of additional study is presented here. Methods: 40 patients who underwent mammaplasty were evaluated by LSG acquired with a SPECT-CT immediately after intradermal periareolar injections of 99mTc -labelled sulphur colloid at two time points: before mammaplasty (Pre-LSG) and between 40 to 60 days after mammaplasty (Post- LSG). Results: The localisation of hot SN was evaluated as in the first study, using the SPECT-CT images : - antero-posterior distance was estimated in centimeter from SLN region to dorsal vertebrae spine center. - SLN’s coronal position was compared to rib cage. The average value of 40 antero-posterior distance before and after surgery was 14.2 vs 14.4 centimeters, in the preliminary study it was 13.6 vs 13.8 centimeters, the difference keeps the same between 2 studies (2 millimeters). As in the first study, SN was in the same position in relation to grill rib. The binomial test did not show statistical difference in lymphatic drainage patterns between Pre-LSG and Post-LSG. Conclusions: after evaluating the impact of the previous mammaplasty surgery on the SLN position, we observed that surgery did not modify lymphatic mapping and thus that it may be possible to propose SLN biopsy even after mammaplasty. This study confirms the results of our preliminary study.

The Influence of Mammaplasty in Axillary Lymphatic Drainage Patterns and Sentinel Lymph Node Detection

Introduction: Controlateral mammaplasty is often necessary during the procedure of breast reconstruction after mastectomy.However the impact of this kind of surgery on axillary lymphatic drainage and sentinel node (SN) detection remains controversial. The American Society of Clinical Oncology (ASCO) as published a guideline in 2005 and recommended that SN biopsy should not be performed in patients with previous mammplasty or axillary surgery.However, because of insufficient evidence and lack of scientific studies, mammaplasty cannot be considered as an absolute contraindication for SN biopsy procedure. Therefore, the same panellists of the ASCO guideline suggested that a preliminary lymphoscintigraphy (LSG) could be done when considering a SN biopsy in patients with previous mammaplasty, with the objective of verifying the integrity of the mammary gland and axillary nodes.The aim of our study was to evaluate the lymphatic patterns and SN detection rates after mammaplasty by using lymphoSPECT-CT (LS).Methods: ten patients who underwent mammaplasty were evaluated by LSG immediately after intradermal periareolar injections of 99mTc -labelled sulphur colloid (NanoCIS*) at two time points: before mammaplasty (Pre-LS) and between 40 to 60 days after mammaplasty (Post- LS).Results: all breasts drained primarily to the axillary SN. The binomial test did not show statistical difference in lymphatic drainage patterns between Pre-LSG and Post-LSG.The average number of hot SN was 1.28 in Pre-LS, 1.14 in Post-LS.The localisation of hot SN was evaluated by:- antero-posterior distance was estimated in centimeter from SN region to dorsal vertebrae spine center-SN's coronal position was compared to grill rib.The preservation of axillary lymphatic drainage after mammaplasty was allowed for SN detection in all studied breasts and the localisation of the sentinel node was the same after surgery than before.Conclusion: after evaluating the impact of the previous mammaplasty surgery on the accuracy of SLN biopsy, we observed that this kind of surgery did not significantly affects the accuracy of lymphatic mapping and that it may be possible to propose sentinel node biopsy after mammaplasty.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1028.

Fourier temporal interpolation improves electrocardiograph-gated myocardial perfusion SPECT

The optimal temporal sampling rate in electrocardiograph-gated myocardial SPECT is questionable: low rates, typically 8 frames per cardiac beat (8fr/cb), favor image quality, whereas high rates, typically 16 frames per cardiac beat (16fr/cb), favor the accuracy of left ventricular (LV) functional parameters. We examined whether Fourier temporal interpolation (FTI) from 8fr/cb to 16fr/cb can combine the advantages of low and high rates.

METHODS

In 34 patients imaged after stress injection of (99m)Tc-sestamibi, 4 sets of reconstructed gated slices were compared: a raw 16fr/cb acquisition (R16), a raw 8fr/cb acquisition (R8), a 16fr/cb set obtained by FTI of 8fr/cb projections (IP), and a 16fr/cb set obtained by FTI of 8fr/cb reconstructed slices (IS). LV ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV) obtained from the final LV volume curve were compared for the 4 datasets. Deviation of the whole LV volume curve was quantified for IP and IS with respect to R16. Image quality was evaluated by consensus reading of end-diastolic slices of the 4 sets. For R16, IP, and IS, cine display fluidity was quantified by a roughness index calculated from the LV volume curve.

RESULTS

No differences in EDVs or ESVs were found among R16, IP, and IS, whereas R8 gave smaller EDVs and larger ESVs. LVEF was lower with R8, IP, and IS than with R16: -3.9%, -1.2%, and -1.3%, respectively. The LV volume curve was closer to R16 with IP than with IS. Image quality was better with IP and IS than with R8 and better with R8 than with R16. Cine display fluidity was better with IP than with R16 and better with R16 than with IS.

CONCLUSION

FTI improved image quality not only over that provided by R16 but even over that provided by R8. The sole worsened LV functional parameter was LVEF, which was slightly underestimated with respect to that estimated by R16. Of the 2 FTI variants, IP was superior to IS for cine display fluidity and accuracy of the LV volume curve with respect to the data obtained with R16. Therefore, FTI to 16fr/cb performed before reconstruction on a pixel-by-pixel basis on 8fr/cb projections improves image quality and cine display fluidity over those of both R8 and R16 acquisitions at the sole cost of a 1% underestimation of LVEF.

Comparative myocardial uptake of technetium-99 m sestamibi and technetium-99m tetrofosmin one hour after stress injection

Technetium-99m sestamibi and 99mTc-tetrofosmin are at present the preferred tracers for simultaneous assessment of myocardial perfusion and function by gated single-photon emission tomography (SPET). The aim of this work was to compare sestamibi and tetrofosmin myocardial uptake 1 h after stress injection. Consecutive unselected patients were studied either with sestamibi or with tetrofosmin on a random basis, until at least 100 patients had been enrolled for each gender and tracer. Stress was obtained by dipyridamole or exercise or combined dipyridamole + exercise; in the latter cases, exercise was sustained for at least 1.5 min after tracer injection. Injected activity was similarly adjusted to body weight. For each patient, imaging began 60-75 min after injection. All SPET projections were summed; due to the acquisition technology ("roving zoom", i.e. a mobile zoom), the heart always appeared at the centre of the frame in all projections and in the sum image. Thus minimal lung background contamination could be assumed in an elliptic region of interest placed over the heart on the sum image. Three indexes were analysed: total myocardial counts (Sum), mean myocardial pixel (Mean) and maximum myocardial pixel (Max). Four patient groups were analysed: males with sestamibi or tetrofosmin (MS: n = 189 and MT: n = 157), females with sestamibi or tetrofosmin (FS: n = 101 and FT: n = 104). MS and MT groups were comparable for physical variables, maximum heart rate and stress type, as were the FS and FT groups. Sum, Mean and Max were significantly higher with sestamibi (P = 0.0001 by ANOVA). Comparing MS vs MT and FS vs FT, mean values +/- SD were as follows: for Sum (kcounts) 750+/-184 vs 652+/-166, and 707+/-202 vs 594+/-189; for Mean (counts) 4517+/-1171 vs 4107+/-898, and 4908+/-1119 vs 4144+/-1025; and for Max (counts) 6471+/-1654 vs 5794+/-1312, and 7318+/-1886 vs 6152+/-1684. The mean gain with sestamibi was +15%, +10% and +12% in males, and +19%, +18% and +19% in females. Similar differences were found within each stress type subgroup. No gender-specific effect was found for Mean, so the overall mean gain was calculated for Mean: +13% for sestamibi vs tetrofosmin. These findings are consistent with other published smaller sample series. Possible differences between tracers with regard to residual activity in syringes were ruled out by an additional experiment. In summary, we found significantly higher myocardial counts with sestamibi than with tetrofosmin, in males as well as in females.

Nycthemeral variations of 99Tcm-labelled heparin pharmacokinetic parameters

Six healthy volunteers (5 males and one female) received four i.v. boluses of 160 U.I. of 99Tcm-heparin at 8.00, 14.00, 20.00 and 02.00 hours at seven-day intervals. Nine blood samples were taken covering a period of 2 h after administration. Simultaneously urine was collected and diuresis was noted. Plasma and urinary radioactivity were measured and standard pharmacokinetic parameters were calculated. Nycthemeral variations of these kinetic parameters were detected by means of distribution-free tests. Circadian rhythms (period = 24 h) were analysed by means of the cosinor method and the Gauss-Marquardt method. The mean raw value of the following parameters: apparent volume of distribution, plasmatic clearance and extra-renal metabolic clearance, increased significantly between 8.00 and 14.00 (p less than 0.01) and decreased between 14.00 and 20.00 (p less than 0.05). A circadian rhythm was found for the plasmatic clearance only (p less than 0.04). On the other hand the elimination half-lives and the renal clearance were unaffected by the time of the injections. These results obtained for low doses of 99Tcm-heparin suggest a circadian rhythm of the bio-availability of heparin in man. This fact should be taken into account for the use of 99Tcm-heparin in the diagnosis of deep-vein thrombosis and for the safe adjustment of the heparin dosages in the treatment of severe thromboembolism.

Plasma transport of 99mTc-p-butyl-IDA

Plasma transport of 99mTc-p-butyl-IDA was measured by four in vitro methods: trichloroacetic acid precipitation, electrophoresis, HPLC, and Scatchard binding isotherm. The data are in accord with protein transport, the main carrier being albumin with two categories of sites. This work suggests that after IV injection of 99mTc-p-butyl-IDA in humans plasma protein binding is one of the limiting factors for the hepatic deposition of the radiopharmaceutical.

[Investigation of biliodigestive anastomosis with the help of radiopharmaceutical products]

Hepatobiliary investigation using 99mTc-diethyl-iminodiacetic acid (IDA) has permitted a new point of view about the morphological and functional investigation of the biliary-digestive anastomosis. Our clinical study concerning 31 patients (13 choledochoduodenostomies 10 hepaticojejunostomies, 6 choledochojejunostomies and 2 cholecystojejunostomies) helped to specify scintigraphic imaging (stasis in intrahepatic bile duct, reflux in stomach, strangulation phenomenon on the level of the mesocolon, incomplete or complete obstruction). The problems associated with current diagnostic procedures are discussed and we place the scintigraphic method amongst other radiologic methods (barium meal, endoscopic retrograde cholangiography and percutaneous transhepatic cholangiography). This non-invasive diagonostic procedure plays a leading part in the investigation of the biliary digestive anastomosis, and particularly in the hepatico-jejunostomies.