Impact of Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography on Therapeutic Decisions and Radiotherapy Planning in Head and Neck Squamous Carcinoma: A Retrospective Study of 46 Patients

BACKGROUND Positron emission tomography/computed tomography (PET/CT) using fluorodeoxyglucose (FDG) is essential in oncology for precise tumor delineation. This study evaluated FDG PET/CT's impact on therapeutic decisions in head and neck cancer, comparing metabolic tumor volumes (MTV) measured by different methods with radiotherapy targets, crucial for treatment planning and patient outcomes. MATERIAL AND METHODS We retrospectively analyzed 46 patients with histologically confirmed head and neck cancer who underwent FDG PET/CT examination before radiotherapy. The mean age was 62 years (46-78 years). Then, we calculated MTV of the primary tumor or local recurrence using a local threshold of 41% of the standard uptake volume (SUV) corrected for lean body mass (SULmax) of the lesion and absolute threshold of SUV 2.5. Descriptive analysis of the recruited patients was assessed based on the clinical database (Medsol). RESULTS The study included 45 patients with squamous carcinoma and 1 with sarcoid cell carcinoma. PET/CT examination led to therapeutic decision changes in 11 cases. No significant difference was found in median values of Gross Tumor Volume (GTV) and MTV absolute (p=0.130). However, significant differences were observed in MTV local, MTV absolute, and GTV median values (p<0.001), with both MTVs showing significant correlation with GTV (p<0.01), especially MTV absolute (r=0.886). CONCLUSIONS FDG PET/CT examination prior to radiotherapy significantly influences therapeutic decisions in head and neck cancer patients. Based on our findings, the absolute threshold method (SUV: 2.5) appears to be an effective approach for calculating MTV for radiotherapy planning purposes.

Performance evaluation of a novel multi-pinhole collimator on triple-NaI-detector SPECT/CT for dedicated myocardial imaging

BACKGROUND

In this study we evaluated the imaging capabilities of a novel Multi-pinhole collimator (MPH-Cardiac) specially designed for nuclear cardiology imaging on a Triple-NaI-detector based SPECT/CT system.

METHODS

^99mTc point source measurements covering the field of view (FOV) were used to determine tomographic sensitivity (TS_pointsource) and spatial resolution. Organ-size tomographic sensitivity (TS_organ) was measured with a left ventricle (LV) phantom filled with typical myocardial activity of a patient scan. Reconstructed image uniformity was measured with a 140 mm diameter uniform cylinder phantom. Using the LV phantom once filled with ^99mTc and after with ¹²³I, Contrast-to-noise ratio (CNR) was measured on the reconstructed images by ROI analysis on the myocardium activity and on the LV cavity. Furthermore, a polar map analysis was performed determining Spill-Over-Ratio in water (SOR_water) and image noise. The results were compared with that of a dual-head parallel-hole low energy high resolution (LEHR) collimator system. A patient with suspected coronary artery disease (CAD) was scanned on the LEHR system using local protocol of 16 min total acquisition time, followed by a 4-min MPH-Cardiac scan.

RESULTS

Peak TS_pointsource was found to be 1013 cps/MBq in the axial center of the FOV while it was decreasing toward the radial edges. TS_organ in the CFOV was found to be 134 cps/MBq and 700 cps/MBq for the LEHR and MPH-Cardiac, respectively. Average spatial resolution throughout the FOV was 4.38 mm FWHM for the MPH-Cardiac collimator. Reconstructed image uniformity values were found to be 0.292% versus 0.214% for the LEHR and MPH-Cardiac measurements, respectively. CNR was found to be higher in case of MPH-Cardiac than for LEHR in case of ^99mTc (15.5 vs. 11.7) as well as for ¹²³I (13.5 vs. 8.3). SOR_water values were found to be 28.83% and 21.1% for the ^99mTc measurements, and 31.44% and 24.33% for the ¹²³I measurements for LEHR and MPH-Cardiac, respectively. Pixel noise of the ^99mTc polar maps resulted in values of 0.38% and 0.24% and of the ¹²³I polar maps 0.62% and 0.21% for LEHR and MPH-Cardiac, respectively. Visually interpreting the patient scan images, MPH-Cardiac resulted in better image contrast compared to the LEHR technique with four times shorter scan duration.

CONCLUSIONS

The significant image quality improvement achieved with dedicated MPH-Cardiac collimator on triple head SPECT/CT system paves the way for short acquisition and low-dose cardiovascular SPECT applications.

Impact of COVID-19 Pandemic on Cardiovascular Testing in Asia

Background

The coronavirus disease-2019 (COVID-19) pandemic significantly affected management of cardiovascular disease around the world. The effect of the pandemic on volume of cardiovascular diagnostic procedures is not known.

Objectives

This study sought to evaluate the effects of the early phase of the COVID-19 pandemic on cardiovascular diagnostic procedures and safety practices in Asia.

Methods

The International Atomic Energy Agency conducted a worldwide survey to assess changes in cardiovascular procedure volume and safety practices caused by COVID-19. Testing volumes were reported for March 2020 and April 2020 and were compared to those from March 2019. Data from 180 centers across 33 Asian countries were grouped into 4 subregions for comparison.

Results

Procedure volumes decreased by 47% from March 2019 to March 2020, showing recovery from March 2020 to April 2020 in Eastern Asia, particularly in China. The majority of centers cancelled outpatient activities and increased time per study. Practice changes included implementing physical distancing and restricting visitors. Although COVID testing was not commonly performed, it was conducted in one-third of facilities in Eastern Asia. The most severe reductions in procedure volumes were observed in lower-income countries, where volumes decreased 81% from March 2019 to April 2020.

Conclusions

The COVID-19 pandemic in Asia caused significant reductions in cardiovascular diagnostic procedures, particularly in low-income countries. Further studies on effects of COVID-19 on cardiovascular outcomes and changes in care delivery are warranted.

Q-Bot: automatic DICOM metadata monitoring for the next level of quality management in nuclear medicine

BACKGROUND

Regular and precise inspection of the realization of the local nuclear medicine standard operation procedures (SOPs) is very complex and time-consuming, especially when large amount of patient data is obtained from a wide scale of different scan procedures on a daily basis. DICOM metadata comprise a complete set of data related to the patient and the imaging procedure, and consequently all information necessary to evaluate the compliance with the actual SOP.

METHODS

Q-Bot, an automatic DICOM metadata monitoring tool which is capable to verify SOP conformities, was tested for 11 months at two nuclear medicine departments. Relevant parameters, such as patient ID, patient mass and height, injected activity, and uptake time, were investigated in the case of adult ¹⁸F-FDG whole-body PET/CT and ^99mTc-MDP gamma camera bone scans on a daily basis. Q-Bot automatically inspected the actual SOP compliance of these relevant DICOM parameters. Q-Bot graphical user interface (GUI) provided a summary of the outliers in a table format to be investigated by a dedicated technologist. In addition, information related to the error handling was also collected for retrospective analysis of long-term tendencies.

RESULTS

In total, 6702 PET/CT and 2502 gamma camera scans were inspected, from which 8581 were confirmed as valid patient study without errors. Discrepancies related to the lack of a parameter, not appropriate format, or improper scan procedures were found in 623 cases, and 156 out of these were corrected before the medical reading and reporting. SOP non-conformities explored with Q-Bot were found to be non-correctable in 467 cases. Systematic errors to our practice turned out to be the manual radiopharmaceutical injection, the allowance to use both SI and non-SI units, and the clear definition of decimal point symbol to use.

CONCLUSION

The daily evaluation of Q-Bot results provided early detection of errors and consequently ensured the minimization of error propagation. Integration of a QM software that inspects protocol compliance at a nuclear medicine department provides significant support to detect non-conformities for technologists, and much higher confidence in image quality for physicians.

Glucose-level dependent brain hypometabolism in type 2 diabetes mellitus and obesity

BACKGROUND

Metabolic syndrome and its individual components lead to wide-ranging consequences, many of which affect the central nervous system. In this study, we compared the [18F]FDG regional brain metabolic pattern of participants with type 2 diabetes mellitus (T2DM) and non-DM obese individuals.

METHODS

In our prospective study, 51 patients with controlled T2DM (ages 50.6 ± 8.0 years) and 45 non-DM obese participants (ages 52.0 ± 9.6 years) were enrolled. Glucose levels measured before PET/CT examination (pre-PET glucose) as well as laboratory parameters assessing glucose and lipid status were determined. NeuroQ application (NeuroQTM 3.6, Syntermed, Philips) was used to evaluate regional brain metabolic differences. [18F]FDG PET/CT (AnyScan PC, Mediso) scans, estimating brain metabolism, were transformed to MNI152 brain map after T1 registration and used for SPM-based group comparison of brain metabolism corrected for pre-PET glucose, and correlation analysis with laboratory parameters.

RESULTS

NeuroQ analysis did not reveal significant regional metabolic defects in either group. Voxel-based group comparison revealed significantly (PFWE<0.05) decreased metabolism in the region of the precuneus and in the right superior frontal gyrus (rSFG) in the diabetic group as compared to the obese patients. Data analysis corrected for pre-PET glucose level showed a hypometabolic difference only in the rSFG in T2DM. Voxel-based correlation analysis showed significant negative correlation of the metabolism in the following brain regions with pre-PET glucose in diabetes: precuneus, left posterior orbital gyrus, right calcarine cortex and right orbital part of inferior frontal gyrus; whilst in the obese group only the right rolandic (pericentral) operculum proved to be sensitive to pre-PET glucose level.

CONCLUSIONS

To our knowledge, this is the first study to perform pre-PET glucose level corrected comparative analysis of brain metabolism in T2DM and obesity. We also examined the pre-PET glucose level dependency of regional cerebral metabolism in the two groups separately. Large-scale future studies are warranted to perform further correlation analysis with the aim of determining the effects of metabolic disturbances on brain metabolism.

Clinical utility of SPECT/CT and CT-dacryocystography-enhanced dacryoscintigraphy in the imaging of lacrimal drainage system obstruction

Purpose

Epiphora is commonly caused by a relative or complete occlusion in the lacrimal drainage system (LDS), principally a nasolacrimal duct obstruction (NLDO). Dacryoscintigraphy (DSG), an extensively assessed imaging technique in diagnosing its abnormalities, can provide only planar images, according to which it needs to be improved. Our aim was to evaluate clinical utility of simultaneous DSG and single-photon emission computed tomography/computed tomography (SPECT/CT) combined with computed tomographic dacryocystography (CT-DCG) in the evaluation of LDS.

Methods

Dynamic imaging with DSG was performed, and tracer radioactivity was detected by a gamma camera. Successively, SPECT/CT images of the involved region were gained, followed by CT-DCG, during which a contrast medium was syringed into the affected LDS, and finally contrast CT scans were obtained again from the same region.

Results

Fifty-seven patients, mean age 54.25 (± 18.26) years all with unilateral NLDO and 32 control subjects, all with patent LDS, mean age 49.88 (± 18.61) years were evaluated in the study. Delayed outflow of tearing eyes was exposed to DSG compared to the fellow and control eyes. The highest value for sensitivity was observed for SPECT/CT, followed by CT-DCG and DSG techniques, while combining DSG with SPECT/CT, DSG with CT-DCG, and SPECT/CT with CT-DCG, the sensitivity increased to 96.49%, 92.98%, and 94.73%, respectively.

Conclusions

Although DSG is a sensitive nuclear medicine method, it only provides useful clinical data when simultaneously supplemented with SPECT/CT and CT-DCG trials as they jointly can offer valuable information about the localization of an abnormality and verify stenosis or obstruction.

Evaluation of the tear clearance rate by dacryoscintigraphy in patients with obstructive meibomian gland dysfunction

PURPOSE

To measure tear clearance values in patients with meibomian gland dysfunction (MGD) with a dynamic nuclear medicine method, namely, dacryoscintigraphy (DSCI).

METHODS

Twenty-four MGD patients and 24 healthy volunteers were examined. During DSCI one drop of a solution with 100 MBq/mL^99mTc sodium pertechnetate was instilled with a micropipette into the lacrimal lake of both eyes. Measurements were performed according to a dynamic data acquisition protocol, which resulted in summed DSCI images. Data were also evaluated separately in special regions of interest (ROI), and consecutive time activity curves were created. Tear clearance (T½) values were calculated based on the activity curves. In addition, tear osmolarity measurements, tear breakup time (tBUT), and Schirmer I (ST_I) tests were performed prior to DSCI examination.

RESULTS

The T½ values were 29.91 ± 11.61 min in MGD patients and 6.26 ± 1.5 min in healthy controls. Tear osmolarity parameters were 308 ± 9.41 mOsm/L and 288.9 ± 6.4 mOsm/L, tBUT values were 5.54 ± 2.73 s and 11.4 ± 2.7 s, while the ST_I test values were 6.17 ± 2.78 mm and 13.58 ± 3.8 mm, respectively. The differences were significant (p < 0.01) in all cases.

CONCLUSIONS

Although the MGD patients' lacrimal drainage systems were patent their tear clearance values were significantly higher than those of healthy volunteers, which may be caused by decreased drainage of tears from the eyes towards the nasal cavity. The understanding of new features regarding the altered physico-chemical characteristics of MGD tears has been augmented by the results of this study.

Activity painting: PET images of freely defined activity distributions applying a novel phantom technique

The aim of this work was to develop a novel phantom that supports the construction of highly reproducible phantoms with arbitrary activity distributions for PET imaging. It could offer a methodology for answering questions related to texture measurements in PET imaging. The basic idea is to move a point source on a 3-D trajectory in the field of view, while continuously acquiring data. The reconstruction results in a 3-D activity concentration map according to the pathway of the point source. A 22Na calibration point source was attached to a high precision robotic arm system, where the 3-D movement was software controlled. 3-D activity distributions of a homogeneous cube, a sphere, a spherical shell and a heart shape were simulated. These distributions were used to measure uniformity and to characterize reproducibility. Two potential applications using the lesion simulation method are presented: evaluation in changes of textural properties related to the position in the PET field of view; scanner comparison based on visual and quantitative evaluation of texture features. A lesion with volume of 50x50x50 mm3 can be simulated during approximately 1 hour. The reproducibility of the movement was found to be >99%. The coefficients of variation of the voxels within a simulated homogeneous cube was 2.34%. Based on 5 consecutive and independent measurements of a 36 mm diameter hot sphere, the coefficient of variation of the mean activity concentration was 0.68%. We obtained up to 18% differences within the values of investigated textural indexes, when measuring a lesion in different radial positions of the PET field of view. In comparison of two different human PET scanners the percentage differences between heterogeneity parameters were in the range of 5-55%. After harmonizing the voxel sizes this range reduced to 2-16%. The general activity distributions provided by the two different vendor show high similarity visually. For the demonstration of the flexibility of this method, the same pattern was also simulated on a small animal PET scanner giving similar results, both quantitatively and visually. 3-D motion of a point source in the PET field of view is capable to create an irregular shaped activity distribution with high reproducibility.

Microcirculation of the fingers in Raynaud’s syndrome

Aim: We investigated the circulatory characteristics of patients suffering of primary and secondary Raynaud’s syndrome. Patients, methods: We examined 106 patients presenting with the classical symptoms of Raynaud’s syndrom (47 primary, 59 secondary) by hand perfusion scintigraphy developed by our Department of Nuclear Medicine. After visual evaluation we analyzed the images semiquantitatively, using the finger to palm ratio. We statistically compared the patients with primary and those with secondary Raynaud’s syndrome. Results: By visual evaluation we constated regional perfusion disturbances in 42 from 59 patients with secondary Raynaud’s syndrome. However, this was observed in only 3 from 47 patients with the primary form of this disease. This difference was statistically significant (p <0.001). Semiquantitative analysis showed that the finger/palm ratios (FPR) were significantly lower (p <0.05) for the patients with primary Raynaud’s syndrome. No differences in the FPR values concerning sex or right and left side. Conclusion: The hand perfusion scintigraphy with 99mTc-DTPA is a noninvasive, cost effective diagnostic tool, which objectively reflects the global and regional microcirculatory abnormalities of the hands, and provides quantitative data for follow-up.

In situ macrophage phenotypic transition is affected by altered cellular composition prior to acute sterile muscle injury

KEY POINTS

The in situ phenotypic switch of macrophages is delayed in acute injury following irradiation. The combination of bone marrow transplantation and local muscle radiation protection allows for the identification of a myeloid cell contribution to tissue repair. PET-MRI allows monitoring of myeloid cell invasion and metabolism. Altered cellular composition prior to acute sterile injury affects the in situ phenotypic transition of invading myeloid cells to repair macrophages. There is reciprocal intercellular communication between local muscle cell compartments, such as PAX7 positive cells, and recruited macrophages during skeletal muscle regeneration.

ABSTRACT

Skeletal muscle regeneration is a complex interplay between various cell types including invading macrophages. Their recruitment to damaged tissues upon acute sterile injuries is necessary for clearance of necrotic debris and for coordination of tissue regeneration. This highly dynamic process is characterized by an in situ transition of infiltrating monocytes from an inflammatory (Ly6C^high ) to a repair (Ly6C^low ) macrophage phenotype. The importance of the macrophage phenotypic shift and the cross-talk of the local muscle tissue with the infiltrating macrophages during tissue regeneration upon injury are not fully understood and their study lacks adequate methodology. Here, using an acute sterile skeletal muscle injury model combined with irradiation, bone marrow transplantation and in vivo imaging, we show that preserved muscle integrity and cell composition prior to the injury is necessary for the repair macrophage phenotypic transition and subsequently for proper and complete tissue regeneration. Importantly, by using a model of in vivo ablation of PAX7 positive cells, we show that this radiosensitive skeletal muscle progenitor pool contributes to macrophage phenotypic transition following acute sterile muscle injury. In addition, local muscle tissue radioprotection by lead shielding during irradiation preserves normal macrophage transition dynamics and subsequently muscle tissue regeneration. Taken together, our data suggest the existence of a more extensive and reciprocal cross-talk between muscle tissue compartments, including satellite cells, and infiltrating myeloid cells upon tissue damage. These interactions shape the macrophage in situ phenotypic shift, which is indispensable for normal muscle tissue repair dynamics.

Myostatin propeptide mutation of the hypermuscular Compact mice decreases the formation of myostatin and improves insulin sensitivity

The TGFβ family member myostatin (growth/differentiation factor-8) is a negative regulator of skeletal muscle growth. The hypermuscular Compact mice carry the 12-bp Mstn(Cmpt-dl1Abc) deletion in the sequence encoding the propeptide region of the precursor promyostatin, and additional modifier genes of the Compact genetic background contribute to determine the full expression of the phenotype. In this study, by using mice strains carrying mutant or wild-type myostatin alleles with the Compact genetic background and nonmutant myostatin with the wild-type background, we studied separately the effect of the Mstn(Cmpt-dl1Abc) mutation or the Compact genetic background on morphology, metabolism, and signaling. We show that both the Compact myostatin mutation and Compact genetic background account for determination of skeletal muscle size. Despite the increased musculature of Compacts, the absolute size of heart and kidney is not influenced by myostatin mutation; however, the Compact genetic background increases them. Both Compact myostatin and genetic background exhibit systemic metabolic effects. The Compact mutation decreases adiposity and improves whole body glucose uptake, insulin sensitivity, and ¹⁸FDG uptake of skeletal muscle and white adipose tissue, whereas the Compact genetic background has the opposite effect. Importantly, the mutation does not prevent the formation of mature myostatin; however, a decrease in myostatin level was observed, leading to altered activation of Smad2, Smad1/5/8, and Akt, and an increased level of p-AS160, a Rab-GTPase-activating protein responsible for GLUT4 translocation. Based on our analysis, the Compact genetic background strengthens the effect of myostatin mutation on muscle mass, but those can compensate for each other when systemic metabolic effects are compared.

A Study on the Basic Criteria for Selecting Heterogeneity Parameters of F18-FDG PET Images

Textural analysis might give new insights into the quantitative characterization of metabolically active tumors. More than thirty textural parameters have been investigated in former F18-FDG studies already. The purpose of the paper is to declare basic requirements as a selection strategy to identify the most appropriate heterogeneity parameters to measure textural features. Our predefined requirements were: a reliable heterogeneity parameter has to be volume independent, reproducible, and suitable for expressing quantitatively the degree of heterogeneity. Based on this criteria, we compared various suggested measures of homogeneity. A homogeneous cylindrical phantom was measured on three different PET/CT scanners using the commonly used protocol. In addition, a custom-made inhomogeneous tumor insert placed into the NEMA image quality phantom was imaged with a set of acquisition times and several different reconstruction protocols. PET data of 65 patients with proven lung lesions were retrospectively analyzed as well. Four heterogeneity parameters out of 27 were found as the most attractive ones to characterize the textural properties of metabolically active tumors in FDG PET images. These four parameters included Entropy, Contrast, Correlation, and Coefficient of Variation. These parameters were independent of delineated tumor volume (bigger than 25-30 ml), provided reproducible values (relative standard deviation< 10%), and showed high sensitivity to changes in heterogeneity. Phantom measurements are a viable way to test the reliability of heterogeneity parameters that would be of interest to nuclear imaging clinicians.

Prognostic value of interim and restaging PET/CT in Hodgkin lymphoma. Results of the CHEAP (Chemotherapy Effectiveness Assessment by PET/CT) study - long term observation

Very few studies have determined the prognostic value of interim and restaging PET/CT in patients with Hodgkin lymphoma using current standard of care therapy outside clinical trials. We analyzed the effect of the results of interim and restaging PET/CT on the survival (overall- and relapse-free) in patients who received standard first-line treatment based on the stage of disease and risk factors. We investigated the differences between the relapse and non-relapse groups based on the clinical pathological characteristics of patients who had positive interim PET/CT results.Between January 1, 2007 and December 31, 2011, the staging, interim and restaging PET/CT scans of patients with Hodgkin lymphoma were analyzed. The Deauville criteria were used for the evaluation of interim PET/CT scans. One hundred and thirteen Hodgkin lymphoma patients underwent staging, interim and restaging PET/CT scans. None of the therapy was modified based on the interim PET/CT results. The median follow-up time was 43.5 months. A total of 62 early stage patients and 51 advanced stage patients were identified. The five-year overall survival rates were 93.4% in the interim PET negative group and 58% in the interim PET positive group (p<0.001). The five-year relapse-free survival rates for the negative and positive groups were 92.7% and 40.8%, respectively (p<0.001). The negative predictive value was 100% in the early stage group and 82.35% in the advanced stage group. By comparison, the positive predictive values were 53.8% and 58.8%, respectively, in these two groups. In the interim PET positive group, patients over 40 years of age had a significantly higher probability of relapse (p=0.057).The routine clinical use of interim PET/CT is highly recommended based on our investigation. However, patients with positive interim PET/CT results required frequent additional evaluations.

[Nuclear medicine in Europe: education]

The technical developments that have taken place in the preceding years (PET, hybrid imaging) have changed nuclear medicine. The future cooperation with radiologists will be challenging as well as positioning nuclear medicine in an European context. It can also be expected that education in nuclear medicine will undergo a harmonization process in the states of the European Union. In this paper, we describe how nuclear medicine education is organized in several European countries. We aim to stimulate constructive discussions on the future development of the specialization in nuclear medicine in Germany.

The value of 18-FDG PET/CT in early-stage breast cancer compared to traditional diagnostic modalities with an emphasis on changes in disease stage designation and treatment plan

BACKGROUND

Proper preoperative staging is vital in the treatment of breast cancer patients. The aim of our study was to assess the value of the diagnostic information provided by PET/CT in surgical practice in breast cancer cases considered early-stage by conventional diagnostic modalities.

METHODS

Whole-body 18-FDG PET/CT was performed on 115 breast cancer patients in whom traditional diagnostic modalities showed no signs of distant metastases or extensive axillary and/or extra-axillary lymphatic spreading, and the size of the primary tumor was <4 cm.

RESULTS

The sensitivity of PET/CT in the detection of the primary tumor was 93%. The sensitivity of the traditional diagnostic modalities in the detection of multifocality was 43.8% while that of PET/CT was 100% (p < 0.001). In the assessment of axillary lymph nodes, ultrasound had a sensitivity of 30% and a specificity of 95%. The corresponding estimates for PET/CT were 72% and 96%, respectively. PET/CT detected distant metastases in 8 patients. TNM classification was modified after PET/CT scanning in 54 patients (47%). PET/CT data changed the treatment plan established upon the results of traditional imaging modalities in 18 patients (15.6%).

CONCLUSIONS

PET/CT is able to assess primary tumor size and axillary lymphatic status more accurately than traditional diagnostic methods. It can detect distant metastases in 7-8% of those patients who were declared free of metastasis by clinical investigations. PET/CT scan modifies the disease stage determined by traditional diagnostic modalities in almost half of the patients and leads to a change in the treatment plan in every 6th patient.

The effect of metoprolol alone and combined metoprolol-felodipin on the digital microcirculation of patients with primary Raynaud's syndrome

OBJECTIVES

Calcium channel inhibitors have beneficial impact on microcirculation, but beta-blocker effect is controversial. Clinicians still do not agree on beta-blocker combination with other treatments in the management of impaired microcirculation. The aim of the present study was to describe the effects of beta-blocker metoprolol monotherapy and combined with calcium channel inhibitor felodipin on digital microcirculation in primary Raynaud's syndrome.

METHODS

We enrolled in this study 46 patients suffering from both hypertension and primary Raynaud's syndrome. Fifteen patients were treated with beta-blocker monotherapy (metoprolol), 13 received combined beta-blocker and calcium channel blocker therapy (felodipin and metoprolol), while 18 patients without any medications served as controls. Measurement of digital microcirculation was carried out with laser Doppler scanner.

RESULTS AND CONCLUSIONS

Our investigation concludes that the concurrent administration of beta-blockers with calcium channel inhibitors positively reduces symptoms in patients suffering from Raynaud's syndrome.

Hextuple registration of interim and follow-up PET-CT images for the accurate tracking of patient recovery after therapy

An extended registration framework is presented to accurately register follow-up PET-CT study triples. Since there are six images to register, sophisticated feature extraction and similarity measurement methods are proposed. An irregular sampling method is introduced to decrease the processing speed of the hextuple registration. The similarity measurement is based on a normalized hybrid extended SSD (Sum of Squared Differences) and and extended NMI (Normalized mutual Information). The method has been tested on a huge amount of simulated data to avoid observer specific results. Based on the validation, our method outperforms prior solutions in both speed and accuracy, hence it should be the subject of further investigations.

Automated lymph node detection and classification on breast and prostate cancer SPECT-CT images

We present a novel detection and classification method to process SPECT-CT images representing breast and prostate lymph nodes. Lymph nodes are those nodes that are near the primer tumor and may become cancerous in time, hence their early detection is a key factor for the successful treatment of the patient. Prior methods focus on the visual aid to manually detect the lymph nodes which still makes the process time-consuming. Other solutions segment the lymph nodes only on CT, where the small lymph nodes may not be located accurately. Our solution processed both SPECT and CT data to provide an accurate classification of all SPECT hot spots. The method has been validated on a huge amount of medical data. Results show that our method is a very effective tool to support physicians working with related images in the field of nuclear medicine.

Raynaud’s Syndrome: comparison of late and early onset forms using hand perfusion scintigraphy

Primary Raynaud's disease is generally a disease of younger females; however, there are cases where symptoms present over the age of 40. These cases are described as late onset. In our current prospective study we compared the characteristics of early and late onset types of primary Raynaud's in 127 patients. In addition to the collection of medical records, we performed capillary-microscopy and hand perfusion scintigraphy using Tc-99 m DTPA to evaluate the microcirculation of each patient's fingers. Regarding the spectrum of the capillary-microscopic findings, we did not find any significant difference between the early and late onset forms. However, in hand perfusion examinations done using Tc-99 m DTPA, we measured a significantly lower finger/palm ratio (FPR) in the early onset group of patients. We also observed a correlation between the duration of the disease and the FPR, as well as between the age and FPR. Longer disease duration resulted in a significantly lower FPR. On the basis of our results, we believe that late onset Raynaud's should be treated as a separate entity. Due to its different characteristics found on examination and follow-up of our patients, functional hand perfusion examination should be recommended independently of the age-related characteristics of the disease.

Imaging of disease activity in Graves' orbitopathy with different methods: comparison of (99m)Tc-DTPA and (99m)Tc-depreotide single photon emission tomography, magnetic resonance imaging and clinical activity scores

BACKGROUND

The immunosuppressive treatment of Graves' orbitopathy (GO) influences the course of the disease in the early, active, retrobulbar inflammatory phase (active GO), which cannot be detected by direct clinical examination.

AIM

To evaluate the clinical effectiveness of a newly developed method for the detection of intraorbital inflammatory activity in patients suffering from Graves' orbitopathy, utilizing a four-headed single photon emission tomograph (SPET) camera and (99m)Tc-diethylenetriamine pentaacetic acid (Tc-DTPA).

METHODS

The magnetic resonance imaging (MRI) T2 relaxation time score, as a measure of ongoing orbital inflammation (reference method), was compared with the uptake activities (UA) of (99m)Tc-DTPA orbital SPET and the more specific (99m)Tc-Neospect ((99m)Tc-depreotide) SPET, as well as the clinical activity scores (CAS), in 21 patients (42 orbits).

RESULTS

By visual inspection, the 'eye SPET' frames of patients suffering from active GO could be easily distinguished from those with inactive GO. Although the distributions of the two radiopharmaceuticals were mildly different, the information obtained was essentially the same. The MRI activity scores correlated well with both (99m)Tc-DTPA and Tc-depreotide UA. The mean (99m)Tc-DTPA UA value of 25 inactive GO orbits was (6.55 +/- 1.4) x 10(-6) ID x cm3 (where ID is the injected dose); the values of the active GO orbits (12 orbits with an MRI score of 1 and five orbits with an MRI score of 2) were significantly higher: (8.87 +/- 1.63) x 10(-6) and (10.36 +/- 1.60) x 10(-6) ID x cm3, respectively. Similar differences were observed for the (99m)Tc-depreotide UA values: the averages in the inactive and active groups with MRI scores of 1 and 2 were (5.23 +/- 1.23) x 10(-6), (7.69+/-2.24) x 10 and (10.92 +/- 3.85) x 10(-6) ID x cm3, respectively. The (99m)Tc-DTPA accumulation pattern in the orbital region of active GO patients was similar to that of the more specific (99m)Tc-depreotide. There was a good correlation (r = 0.71, P<0.001) between the UA values of the two radiopharmaceuticals, but CAS did not correlate with either of the UA values.

CONCLUSIONS

(99m)Tc-DTPA eye SPET is a potentially useful method, allowing rapid imaging at an acceptable cost. It provides essential supplementary information to traditional CAS in assessing disease activity in Graves' orbitopathy.

Evaluation of interstitial lung disease in mixed connective tissue disease (MCTD)

OBJECTIVE

Interstitial lung disease (ILD) may be a characteristic, often serious, manifestation of mixed connective tissue disease (MCTD). In this retrospective study, the frequency and clinical picture of ILD were determined in patients with MCTD using two diagnostic tests: high-resolution computed tomography (HRCT) and inhaled aerosol clearance times of (99m)Tc-labelled diethylene-triamine pentaacetate ((99m)Tc-DTPA). In addition, pulmonary function, effects of therapy and a variety of immunoserological markers were also assessed.

METHODS

One hundred and forty-four consecutive patients with MCTD were selected from the clinic, irrespective of the presence or absence of ILD. All patients underwent a detailed clinical assessment, chest HRCT scanning, chest radiography, inhaled aerosol of (99m)Tc-DTPA clearance times, and all pulmonary function tests. Patients who had active ILD received corticosteroid (CS) or CS in combination with cyclophosphamide (CPH). All investigations were repeated after 6 months of immunosuppressive therapy.

RESULTS

Ninety-six out of 144 MCTD patients (66.6%) had active ILD, 75 of this group (78.1%) showed ground glass opacity, 21 patients (21.8%) ground glass opacity with mild fibrosis with HRCT. Forty-five patients with active ILD received 2 mg/kg/day CS for 6-8 weeks alone and 51 patients CS in combination with CPH (2 mg/kg/day). Six months later, after therapy, 67 out of 96 MCTD patients with ILD (69.8%) showed a negative HRCT pattern, ground glass opacity with mild fibrosis developed in 15 patients (15.6%), and fibrosis was detected in 13 patients (13.5%). Only one patient showed subpleural honeycombing. (99m)Tc-DTPA was rapid in all 96 MCTD patients with active ILD (28.7 +/- 8.2 min, normal value >40 min). After therapy the (99m)Tc-DTPA was normalized, 79 out of 96 patients (82.3%). Carbon monoxide diffusion capacity (DLCO) was reduced in 33 out of 96 MCTD patients with active ILD (34.3%), while there were no significant differences in the pulmonary function tests between the active versus inactive stage of ILD or versus patients without ILD. The sera of 96 MCTD patients with active ILD contained a high level of immune complexes (ICs), and the total haemolytic complement levels (CH50/ml U) decreased. After 6 months of therapy, the IC levels decreased and CH50/ml levels normalized (MCTD patients before and after active ILD: IC optical density = 355 +/- 227 vs 206 +/- 92, P<0.001; CH50/ml, 38.0 +/- 12.6 U vs 64.3 +/- 13.0 U, P<0.001).

CONCLUSIONS

HRCT is the gold standard for diagnosis of ILD. However, we used another method, (99m)Tc-DTPA, in order to compare this technique with HRCT. This latter technique has not been studied previously in MCTD. The elevated levels of IC and increased complement consumption indicated that IC-mediated alveolocapillary membrane damage and tissue injury might play a role in the pathogenesis of ILD in MCTD.

Microcirculation of the fingers in Raynaud's syndrome: (99m)Tc-DTPA imaging

AIM

We investigated the circulatory characteristics of patients suffering of primary and secondary Raynaud's syndrome.

PATIENTS, METHODS

We examined 106 patients presenting with the classical symptoms of Raynaud's syndrom (47 primary, 59 secondary) by hand perfusion scintigraphy developed by our Department of Nuclear Medicine. After visual evaluation we analyzed the images semiquantitatively, using the finger to palm ratio. We statistically compared the patients with primary and those with secondary Raynaud's syndrome.

RESULTS

By visual evaluation we constated regional perfusion disturbances in 42 from 59 patients with secondary Raynaud's syndrome. However, this was observed in only 3 from 47 patients with the primary form of this disease. This difference was statistically significant (p<0.001). Semiquantitative analysis showed that the finger/palm ratios (FPR) were significantly lower (p<0.05) for the patients with primary Raynaud's syndrome. No differences in the FPR values concerning sex or right and left side.

CONCLUSION

The hand perfusion scintigraphy with (99m)Tc-DTPA is a noninvasive, cost effective diagnostic tool, which objectively reflects the global and regional microcirculatory abnormalities of the hands, and provides quantitative data for follow-up.

SPECT using 99mTc-DTPA for the assessment of disease activity in Graves' ophthalmopathy: a comparison with the results from MRI

Currently available methods for the estimation of disease activity in the orbits of patients with Graves' ophthalmopathy (GO) have the disadvantages of being either expensive or time consuming. The aim of this study was to develop a quick, reliable method using Tc labelled diethylenetriaminepentaacetic acid (DTPA) and four-headed single photon emission computed tomography (SPECT) for this purpose. The theoretical basis of the method is that the high capillarization and oedema in the orbit may be reflected on Tc-DTPA images in GO. SPECT data of 28 orbits of 14 patients with GO were compared with magnetic resonance imaging (MRI) T2 relaxation time scores. Based on the number of 'active' muscles with T2 relaxation times of more than 70 ms in a given orbit, an MRI score of 0 (no active muscle) to 4 (all rectus muscles active) was assigned to the orbit. With MRI, 18 orbits were inactive, and 10 were active. Thirty minutes after the intravenous administration of 7 MBq.kg Tc-DTPA, 128 projections were acquired by a four-headed SPECT. On the sum of six transaxial slices containing the entire bulbar region of the skull, a triangle-like region of interest (ROI) was drawn (OR ROI). This ROI was 'slipped' to the right temporal region of the brain as reference site (B ROI). The count ratios of OR/B were calculated and compared to MRI score values. In the group of 18 inactive orbits (an MRI score of zero on both sides), in the transaxial plane, the mean OR/B value was 6.4+/-1.17, and in the group of 10 active orbits (an MRI score of 1-3) 8.30+/-2.08, the difference being significant (P <0.05). Tc-DTPA orbital SPECT is a promising method for the estimation of disease activity in the orbits of patients with Graves' ophthalmopathy.

Quantitative assessment of blood flow reserve using 99mTc-HMPAO in carotid stenosis

Dynamic imaging of the inflow of technetium-99m hexamethylpropylene amine oxime (HMPAO) to the brain has been proved to allow estimation of the hemispherical cerebral blood flow (CBF) using the Patlak plot. In this study, we compared the hemispherical CBF (in ml/min/100 g) of different patient groups. A total of 25 patients (comprising 13 with migraine and 12 scheduled for endarterectomy owing to angiographically confirmed severe stenosis of the internal carotid artery on at least one side) underwent baseline and acetazolamide 99mTc-HMPAO brain perfusion studies. In addition, acetazolamide 99mTc-HMPAO studies were performed in 12 healthy subjects (no baseline study was performed for ethical reasons.) Dynamic studies were acquired by means of a dual-detector gamma camera with a large field of view (HELIX, Elscint). Special difference images were created to make definition of the aortic arch and hemispherical brain regions easier and more reproducible. A semi-automatic method was developed to determine the transit time from the aorta to the brain, making the generation of the Patlak plot even more robust. The baseline CBF values did not significantly depend on the disease (P>0.1), whereas the CBF values obtained after acetazolamide provocation did do so (ANOVA, P<0.001). Patients suffering from migraine showed a significant increase in global CBF values after acetazolamide provocation (paired t test, P<0.05), but we could not find any effect of the provocation in patients awaiting carotid endarterectomy, indicating a lack of cerebrovascular reserve capacity. Comparison of the results of the acetazolamide study in patients and the control group revealed the CBF values to be significantly lower in patients with carotid stenosis (two-sample t-test, P<0.001), but not in those with migraine (P>0.1). In summary, using quantitative analysis of 99mTc-HMPAO brain studies we could objectively compare the CBF of patients suffering from different diseases. Especially the CBF values obtained after acetazolamide provocation permitted effective differentiation of disease states. The quantitative results may be of assistance in therapy planning, e.g. in selection of the correct operative technique.

99m Tc-HMPAO labelled leukocyte scintigraphy in patients with rheumatoid arthritis: a comparison with disease activity

The aim of this study was to test the applicability of 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leukocyte joint scintigraphy in the assessment of disease activity in 21 patients with rheumatoid arthritis, and to compare leukocyte scintigraphy with the Disease Activity Score (DAS), a validated activity index developed by the European League Against Rheumatism (EULAR). Twenty-one patients with rheumatoid arthritis were investigated by using 99mTc-HMPAO labelled leukocyte joint scintigraphy. The clinical and laboratory data were recorded, and the DAS was calculated and compared with the scintigraphic results in each case. A relatively high DAS score (4.71+/-1.07) was found in the majority of patients. The degree of accumulation of 99mTc-HMPAO leukocytes showed no correlation with a patient's age, gender, duration of disease, use of disease modifying anti-rheumatic drugs (DMARDs), visual analogue scale (VAS), Richie index, DAS, or any laboratory parameters. In contrast, a significant correlation was found between the global regional accumulation of the labelled leukocytes of the hands and feet, and the swollen-joint count. It is concluded that radiolabelled leukocyte scintigraphy could become one of the promising methods in the assessment of disease activity in patients with rheumatoid arthritis.

[Fifteen years experience in the surgical treatment of primary hyperparathyroidism]

We measured the efficacy of preoperative localization techniques and results of parathyroidectomy in patients with primary hyperparathyroidism (HPT). From 1986 to 2001, 92 patients were treated with primary HPT. Preoperative localization technique was used in all patients (US n = 85, Tc-99m-sestamibi/Tc-99m-pertechnetate subtraction scintigraphy n = 67, CT n = 18, MRI n = 14) to visualize the abnormal parathyroids. Results of localization studies were compared with surgical and pathological findings. Bilateral neck exploration was carried out in each patient for the identification of all parathyroid glands. If parathyroid adenoma was diagnosed, exstirpation of the abnormal parathyroid was performed. If diffuse hyperplasia was diagnosed, subtotal parathyroidectomy (3 1/2) was performed. The overall sensitivity was 94% for scintigraphy, 74% for US, 67% for CT and 50% for MRI. The PPV was 97% for scintigraphy, 92% for US, 100% for CT and for MRI. At surgery 66 patients had single adenomas and 3 patients had double adenomas. Diffuse hyperplasia was diagnosed in 21 and parathyroid carcinoma was found in 2 patients. Persistent HPT was noted in 1 patient. Recurrent HTP occurred 4 times. After a second operation their HPT disappeared. In conclusion, the sensitivity of Technetium-99m-sestambi and Technetium-99m-pertechnetate subtraction scanning was significantly superior compared to other localization methods. The use of these sensitive preoperative technique can improve the success rate, and decrease the incidence of persistent and recurrent HPT.

[The role of MIBI scintigraphy in the early detection of breast cancer]

The authors investigate the role of MIBI scintigraphy in the early diagnosis of breast cancer. The importance of early diagnosis is emphasized by the fact that breast cancer has the highest morbidity and mortality preceding cervical carcinoma amongst women. Retrospective examinations were made in case of 42 patients operated before because of breast cancer in order to examine accuracy of both mammography and scintigraphy in comparison with the results of histological diagnosis. In these cases sensitivity of scintigraphy turned out to be 69%, while its specificity 42%. In cases of mammographical investigations the sensitivity proved to be 74% and specificity was 61%. Besides mammography, scintigraphy has a very important additional role in the diagnosis of breast cancer. Because of its results and costs scintigraphy is not able to take over the mammography's dominant position (as a popular diagnostic method) but in selected patients' groups it can help to realise tumors as well as to avoid unnecessary operations or needle biopsis. Based on our results this method can give significant additional information in T1b and especially in T1c states of tumors. Therefore this method can be offered as an additional investigation in cases of physically realised or mammographically screened, but not-palpable, larger than 1 cm size lumps when there is little or moderate risk of malignancy.

The clinical usefulness of the fingers-to-palm ratio in different hand microcirculatory abnormalities

A non-invasive nuclear medicine technique was developed to screen patients with painful hands so as to separate patients with a normal from those with an abnormal microcirculation of the hands in different clinical conditions. Such a technique is important, as the other methods available are either subjective or rather complicated. The study population consisted of 10 healthy individuals, 23 patients with Raynaud's syndrome and 15 patients with mixed connective tissue disease (MCTD). Sixty gamma-camera images of the hands (1 s each) were recorded after a bolus injection of 99Tcm-DTPA via a dorsal foot vein. Regions of interest were drawn on the summed images around the fingers and the palmar region. The fingers-to-palm ratio was then calculated from the total counts inside these regions of interest separately for each hand. The mean fingers-to-palm ratio was 0.94+/-0.18 (0.71-1.25) for the healthy group, 0.57+/-0.22 (0.21+/-1.11) for the MCTD group and 0.40+/-0.14 (0.18-0.77) for the Raynaud's patients. Analysis of variance showed these differences to be highly significant (P < 0.001). There were also significant differences between 6 MCTD patients in an active (mean 0.48) and nine patients in an inactive (mean 0.66) clinical state (two-sample t-test: P < 0.05). There were no significant differences between the fingers-to-palm ratios of the left and right hands of the same patients (one-sample t-test). Of the 23 primary Raynaud's patients, capillary microscopic data were pathological in only eight (34%). We conclude that our method is able to differentiate between patients with normal and those with abnormal microcirculation of the hands. Although measurement of the fingers-to-palm ratio is not a specific method, it is useful both for staging and in the follow-up of patients.

[Study of the contractility of the gallbladder by ceruletide infusion cholescintigraphy after litholysis]

Twenty-six randomly selected patients 2-6 years (mean: 3.5) after rapid percutaneous catheteric litholysis at the Radiological Department were investigated by quantitative Ceruletide cholescintigraphy in this pilot study. The average EF of the patients with recurrent gallstones (Group II) was lower (55 +/- 23%) than that of the patients without stones (69 +/- 23%) (Group I). The authors conclude that this scintigraphic method could help not only to select the best method to make patient stonefree but has an important role in forecasting the prognosis of gallstone recovery after litholytic therapy.