Quantitative SPECT: the time is now

Background

Quantification is one of the key benefits of nuclear medicine imaging. Recently, driven by the demand for post radionuclide therapy imaging, quantitative SPECT has moved from relative and semiquantitative measures to absolute quantification in terms of activity concentration, and yet further to normalised uptake using the standard uptake value (SUV). This expansion of quantitative SPECT has the potential to be a useful tool in the nuclear medicine armoury, but key factors must be addressed before it can meet its full potential.

Discussion

Quantitative SPECT should address an unmet clinical need and give metrics that are clinically meaningful. Using the technique in a similar manner to PET with longitudinal assessments of disease in terms of SUV is one example that meets these criteria. Having metrics that are evaluated to ensure that they are correct, that are optimised to maximise their sensitivity, and that are transferrable to allow multi-centre learning and applicability to all users of the technology are other areas of quantitative SPECT that need to be addressed and that have specific challenges associated with them. Finally, ensuring quantitative SPECT is cost-effective in times when healthcare budgets are being squeezed is also very important.

Conclusion

Quantitative SPECT offers the possibility to continue and expand the potential of quantitative nuclear medicine applications. The time is now to ensure that our community works together to make this potential a reality.

EANM practice guideline for quantitative SPECT-CT

PURPOSE

Quantitative SPECT-CT is a modality of growing importance with initial developments in post radionuclide therapy dosimetry, and more recent expansion into bone, cardiac and brain imaging together with the concept of theranostics more generally. The aim of this document is to provide guidelines for nuclear medicine departments setting up and developing their quantitative SPECT-CT service with guidance on protocols, harmonisation and clinical use cases.

METHODS

These practice guidelines were written by members of the European Association of Nuclear Medicine Physics, Dosimetry, Oncology and Bone committees representing the current major stakeholders in Quantitative SPECT-CT. The guidelines have also been reviewed and approved by all EANM committees and have been endorsed by the European Association of Nuclear Medicine.

CONCLUSION

The present practice guidelines will help practitioners, scientists and researchers perform high-quality quantitative SPECT-CT and will provide a framework for the continuing development of quantitative SPECT-CT as an established modality.

Planar scintigraphy with 123I/99mTc-sestamibi, 99mTc-sestamibi SPECT/CT, 11C-methionine PET/CT, or selective venous sampling before reoperation of primary hyperparathyroidism?

All patients with primary hyperparathyroidism should undergo localization studies before reoperation, but it is not known which method is most accurate. The purpose of this prospective study was to compare the performance of planar scintigraphy with (123)I/(99m)Tc-sestamibi, (99m)Tc-sestamibi SPECT (SPECT/CT), (11)C-methionine PET/CT, and selective venous sampling (SVS) in persistent primary hyperparathyroidism.

METHODS

Twenty-one patients referred for reoperation of persistent hyperparathyroidism were included and investigated with (123)I/(99m)Tc-sestamibi, SPECT/CT (n = 19), (11)C-methionine PET/CT, and SVS (n = 18) before reoperation. All patients had been operated on 1-2 times previously because of hyperparathyroidism. The results of the localization studies were compared with operative findings, histology, and biochemical cure.

RESULTS

Eighteen (86%) of 21 patients were biochemically cured. Nineteen parathyroid glands (9 adenomas, 1 atypical adenoma, and 9 hyperplastic glands) were removed from 17 patients, and 1 patient who was biochemically cured had an unclear histology result. The accuracy for localizing a pathologic parathyroid gland to the correct side of the neck was 59% (95% confidence interval [CI], 36%-79%) for (123)I/(99m)Tc-sestamibi, 19% (95% CI, 5%-42%) for SPECT/CT, 65% (95% CI, 43%-84%) for (11)C-methionine PET/CT, and 40% (95% CI, 19%-65%) for SVS (P < 0.01 for (123)I/(99m)Tc-sestamibi vs. SPECT/CT). The corresponding accuracy for the correct quadrant or more specific site was 48% (95% CI, 27%-69%) for (123)I/(99m)Tc-sestamibi, 14% (95% CI, 3%-36%) for SPECT/CT, 61% (95% CI, 39%-80%) for (11)C-methionine PET/CT, and 25% (95% CI, 9%-49%) for SVS (P < 0.02 for (123)I/(99m)Tc-sestamibi vs. SPECT/CT). In the 3 patients not cured, preoperative (123)I/(99m)Tc-sestamibi and SPECT/CT remained negative, SVS was false predictive in all, and (11)C-methionine PET/CT in 1. (11)C-methionine PET/CT accurately revealed the pathologic gland in 4 of 8 (50%) patients with a negative (123)I/(99m)Tc-sestamibi scan result, all of whom were biochemically cured after reoperation.

CONCLUSION

Planar scintigraphy with (123)I/(99m)Tc-sestamibi performs well in complicated primary hyperparathyroidism and is recommended as first-line imaging before reoperation. (11)C-methionine PET/CT provides valuable additional information if (123)I/(99m)Tc-sestamibi scan results remain negative. (99m)Tc-sestamibi SPECT/CT and SVS provide no additional information, compared with the combined results of (123)I/(99m)Tc-sestamibi and (11)C-methionine PET/CT imaging.

99mTc SPECT/CT Versus Planar Lymphoscintigraphy for Preoperative Sentinel Lymph Node Detection in Cervical Cancer: A Systematic Review and Metaanalysis

We aimed to compare SPECT/CT and lymphoscintigraphy on overall and bilateral sentinel lymph node (SLN) detection in cervical cancer patients.

METHODS

A systematic search was performed on August 1, 2014, in PubMed, Embase, Scopus, and the Cochrane library. The syntax was based on synonyms of the terms cervical cancer, SPECT/CT, and lymphoscintigraphy. Retrieved articles were screened on their title/abstract and considered eligible when an SLN procedure was performed using both imaging modalities and if detection results were reported. Two independent reviewers assessed all included studies on methodologic quality using QUADAS-2. Studies were pooled on their odds ratios (ORs) with a random-effects model.

RESULTS

The search yielded 962 unique articles, of which 8 were ultimately included. The studies were recent retrospective or prospective cohort studies of limited size (n = 7-51) but sufficient methodologic quality. The median overall detection (≥1 SLN in a patient) was 98.6% for SPECT/CT (range, 92.2%-100.0%) and 85.3% for lymphoscintigraphy (range, 70.0%-100.0%). This corresponded to a pooled overall SLN detection OR of 2.5 (95% CI, 1.2-5.3) in favor of SPECT/CT. The reported median bilateral detection (≥1 SLN in each hemipelvis) was 69.0% for SPECT/CT (range, 62.7%-79.3%) and 66.7% for lymphoscintigraphy (range, 56.9%-75.8%), yielding a pooled OR of 1.2 (95% CI, 0.7-2.1). No significant difference in the number of visualized SLNs was observed at a pooled ratio of 1.2 (95% CI, 0.9-1.6).

CONCLUSION

In cervical cancer patients, preoperative SLN imaging with SPECT/CT results in superior overall SLN detection in comparison with planar lymphoscintigraphy.

99mTc-HDP SPECT-CT Aids Localization of Joint Injections in Degenerative Joint Disease of the Foot and Ankle

BACKGROUND

Pain relating to degenerative joint disease within the foot and ankle can be difficult to localize with clinical examination alone due to the complex anatomy of the joints. The aim of this study was to determine whether single-photon emission computed tomography combined with conventional computed tomography (SPECT-CT) could be used to localize the site of degenerative joint disease for intra-articular injection and thereby improve the clinical success of the procedure.

METHODS

A prospective study was performed involving 203 patients who had undergone triple-phase (99m)Tc-hydroxymethylene diphosphonate bone scans with SPECT-CT of the foot and ankle for degenerative joint disease. Fifty-two patients went on to have joint injections for degenerative joint disease, with clinical follow-up. Correlation with the clinical diagnosis and the outcome of intra-articular injections with 0.5% bupivacaine and 80 mg of Depo-Medrone was performed. A successful outcome was determined by an improvement in the visual analog pain score of at least 50%.

RESULTS

In 19 (37%) patients, the site of degenerative joint disease determined by SPECT-CT differed from the initial clinical assessment and resulted in a change in management. Overall, 46 (88%) patients showed an improvement in symptoms.

CONCLUSION

The study demonstrated a high clinical success rate for SPECT-CT-guided joint injections. The technique was useful in localizing degenerative joint disease of the ankle, hindfoot, and midfoot as an adjunct to clinical examination.

LEVEL OF EVIDENCE

Level IV, case series.

Soluble CD146 boosts therapeutic effect of endothelial progenitors through proteolytic processing of short CD146 isoform

AIMS

Endothelial colony-forming cells (ECFC) constitute an endothelial progenitor fraction with a promising interest for the treatment of ischaemic cardiovascular diseases. As soluble CD146 (sCD146) is a new factor promoting angiogenesis, we examined whether sCD146 priming could improve the therapeutic potential of ECFC and defined the involved mechanism.

METHODS AND RESULTS

We investigated the effects of sCD146 priming on regenerative properties of ECFC in vivo. In a mouse model of hindlimb ischaemia, the homing of radiolabelled cells to ischaemic tissue was assessed by SPECT-CT imaging. Soluble CD146 priming did not modify the number of engrafted ECFC but improved their survival capacity, leading to an enhanced revascularization. The mechanism of action of sCD146 on ECFC was studied in vitro. We showed that sCD146 acts in ECFC through a signalosome, located in lipid rafts, containing angiomotin, the short isoform of CD146 (shCD146), VEGFR1, VEGFR2, and presenilin-1. Soluble CD146 induced a sequential proteolytic cleavage of shCD146, with an extracellular shedding followed by an intramembrane cleavage mediated by matrix metalloprotease (MMP)/ADAM and presenilin-1, respectively. The generated intracellular part of shCD146 was directed towards the nucleus where it associated with the transcription factor CSL and modulated the transcription of genes involved in cell survival (FADD, Bcl-xl) and angiogenesis (eNOS). This effect was dependent on both VEGFR1 and VEGFR2, which were rapidly phosphorylated by sCD146.

CONCLUSIONS

These findings establish that activation of the proteolytic processing of shCD146, in particular by sCD146, constitutes a promising pathway to improve endothelial progenitors' regenerative properties for the treatment of cardiovascular diseases.

Personalized & Precision Medicine in Cancer: A Theranostic Approach

BACKGROUND AND OBJECTIVES

There are many challenges in the execution of targeted therapy in cancer due to tumor heterogeneity between individuals. In case of solid tumors this is one of the reasons as to why genomic analysis from single tumor biopsy specimens underestimate the mutational burdens in such heterogeneous tumors thus contributing to treatment failure and drug resistance. Molecular characteristics redefine tumor classification for molecular targeted therapies ensuring the best patient specific therapies with better specificity and cost effective ratio. Functional imaging like Positron Emission Tomography & Computed Tomography (PET-CT) with 18-F Fluorodeoxyglucose (FDG) has been extensively used in oncology to assess the glucose metabolism in tumor cells since long. It has been further redefined to use other radiopharmaceutical targets capable of tumor characterization, microenvironment, angiogenesis, proliferation, apoptosis, receptor expression and few others. Among these the receptor expression in tumors have been studied in detail and specific imaging probes have been developed for imaging with either Single Photon Emission Computed Tomography (SPECT-CT) or PET-CT. Combination of these diagnostic tool with the same vector has permitted an easy switch from diagnosis to therapy using a therapeutic radionuclide when such expression is documented. Thus in Nuclear Medicine the concept of Theranostics have been utilized with ease and successfully implemented the theranostic concept and has become a valid example of personalized and precision medicine. Imaging and therapy of thyroid cancer, neuroendocrine tumors and castration resistant prostate cancer are current examples of this concept.

CONCLUSION

Molecular imaging has high potential to link target identification with therapy and thus to personalize it. It also has a very high potential for in-vivo tissue characterization, to improve prediction, prognostication, road map for biopsy and monitoring of therapy.

Increased Osseous (99m)Tc-DPD Uptake in End-Stage Ankle Osteoarthritis: Correlation Between SPECT-CT Imaging and Histologic Findings

BACKGROUND

We analyzed the histopathologic findings in end-stage osteoarthritic ankle joint tissue that display increased uptake of bone-seeking radiotracer in single-photon emission computed tomography-computed tomography (SPECT-CT) imaging.

METHODS

Six consecutive patients with end-stage osteoarthritis undergoing total ankle replacement received preoperative SPECT-CT imaging using (99m)Technetium dicarboxypropane diphosphonate ((99m)Tc-DPD). Using imaging data for stratification, osteochondral tissue sections were prepared from SPECT-positive (+) and -negative (-) areas of tibial and talar resection specimens. Histomorphometric analyses of osteoblast numbers, collagen deposition, and cartilage degeneration were performed on hematoxylin and eosin, van Gieson's and Safranin-O stained tissue sections. Osteoclast activity was visualized using tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

Increased (99m)Tc-DPD uptake was observed exclusively subjacent to the subchondral bone plate of tibial and talar joint compartments. SPECT(-) tissues displayed typical fatty marrow morphology containing mainly collagen-positive blood vessels and few marrow and bone-lining cells. SPECT(+) tissues were characterized by increased numbers of active bone-lining osteoblasts depositing collagen fibers. Collagen area fraction of subchondral bone marrow was significantly increased in SPECT(+) (0.52 ± 0.21) compared with SPECT(-) (0.29 ± 0.13) tissues (P = .30). Multinucleated TRAP(+) osteoclasts were absent from bone formation sites, but associated with vascular structures invading articular cartilage through the subchondral bone plate. Increased (99m)Tc-DPD uptake was specifically and strongly correlated with increased osteoblast numbers (P = .011), and with collagen area fraction (P = .030) but not with Mankin score (P = .202), or with osteoclast number (P = .576).

CONCLUSION

Subchondral bone tissues in SPECT(+) areas of end-stage ankle osteoarthritis were histologically characterized by increased osteoblast-mediated bone formation in the absence of functional osteoclasts, and increased cellularity and collagen deposition in marrow tissues.

CLINICAL SIGNIFICANCE

Our findings suggest a pathologic bone-remodeling process in end-stage ankle OA areas with increased (99m)Tc-DPD uptake.

SPECT-CT Imaging with [99mTc]PSMA-T4 in patients with Recurrent Prostate Cancer

BACKGROUND

Prostate-specific membrane antigen (PSMA) is a cell surface glycoprotein with a large extracellular domain with overexpression of the prostatic tumour cells. Several small molecules of PSMA ligands of inhibitors binding to the active site of PSMA were developed. [99mTc]Tc-PSMA-T4 is a new radiopharmaceutical (Polatom) for imaging loco-regional metastases and/or local relapse in patients with prostate cancer. The purpose of this work was to evaluate the clinical application of SPECT-CT imaging with [99mTc]Tc-PSMA-T4 in patients with recurrent prostate cancer.

MATERIAL AND METHODS

Thirty-six patients with prostate cancer, aged 60-80 years with biochemical relapse of PSA (ranged from 0.1 to 73 ng/mL) were included. Three patients were studied after tru-cut biopsy, hormonal and cytoreductive radiotherapy and 33 patients out of 36 - after radical treatment (total prostatectomy or definitive radiotherapy of the tumour). All of them underwent whole-body imaging examinations with subsequent target SPECT-CT studies of the pelvis, abdomen and/or chest, 1-3 hrs post i.v. administration of [99mTc]Tc-PSMA-T4. The average activity dose was 6.3 MBq/kg in a man of 70 kg. A Dual-head SPECT-CT gamma camera with a low dose CT scan (Symbia T2, Siemens) was used. The images were interpreted based on all other clinical and radiological data. Follow-up could be conducted in 11/36 patients during that period.

RESULTS

Normal biodistribution of the radiopharmaceutical with high activity background was observed in the liver, spleen, kidneys, lacrimal and salivary glands, bowels and urinary bladder. Positive imaging for local relapse in the prostate bad was imaged in 21 patients, lymph node metastases - in 16 cases, bone lesions - in 10 cases, pulmonary metastases - in 2 cases, hepatic lesions were visualised in one of them and in another - adrenal suprarenal metastasis with intensive tracer uptake significant for overexpression of PSMA. There was a suspicion for local recurrences in 4 patients with negative MRT studies who were followed up. In 3 cases, previously treated bone metastases were partially negative without tracer uptake, only some progressive bone lesions were positive. Five patients were with negative results. Sensitivity was 84.37% (27/32), specificity - 100% (4/4) and accuracy - 86.11% (31/36).

CONCLUSIONS

In conclusion SPECT-CT imaging with [99mTc]Tc-PSMA-T4 could be applied in patients with prostate cancer for the diagnosis of recurrent disease to determine personalized treatment for each patient. Specific uptake of this tracer, depicted by SPECT-CT images has clinical importance of identifying and assessing PSMA expression before consideration of Radio Ligand Therapy (RLT) with [¹⁷⁷Lu]Lu-PSMA. SPECT-CT imaging with [99mTc]PSMA is promising and reliable nuclear medicine approach to monitoring therapeutic effect after treatment and for restaging of the disease.

Relevance of SPECT-CT in Complex Cases of Foot and Ankle Surgery: A Comparison With MRI

BACKGROUND

Finding the right diagnoses in patients with complex foot and ankle disorders can be challenging. Single-photon emission computed tomography and computed tomography (SPECT-CT) has shown to be feasible in foot and ankle surgery. The aim of this study was to evaluate the reliability and accuracy of SPECT-CT and thereby its impact on final treatment decision compared with magnetic resonance imaging (MRI).

METHODS

A retrospective study was performed on 49 patients treated at our institution. Experienced foot and ankle surgeons independently, and blinded, analyzed clinical data and radiographs together with MRI, SPECT-CT, or a combination of both. Based on the determined final treatment decision Cohen's kappa values were calculated to illustrate interrater and intrarater reliability.

RESULTS

The kappa values for interrater reliability were higher for SPECT-CT at .68 and MRI + SPECT-CT at .71 compared to 0.38 for MRI alone (P < .05). The kappa values for intrarater reliability of MRI + SPECT-CT were higher at .75 compared with SPECT-CT alone at .67 (P < .05) and MRI at .35 (P < .01).

CONCLUSION

We found a higher interrater and intrarater reliability for SPECT-CT compared with MRI alone for diagnosing complex foot and ankle pathologies. SPECT-CT has a high impact on final treatment decision. The main indications are bony pathologies with diagnostic uncertainty especially in closely adjacent structures as the joints of the midfoot, occult coalitio, stress fractures, verification or exclusion of nonfusion, periprosthetic disorders after total ankle replacement and osteochondral lesion in cases of combined pathologies.Levels of Evidence: Level IV: Retrospective study.

Correlation of Single-Photon Emission Computed Tomography Results With Clinical and Intraoperative Findings in Painful Total Ankle Replacement

BACKGROUND

Evaluating pain after total ankle replacement (TAR) is often difficult, and traditional imaging modalities do not always adequately assess potential etiologies of failure. Our study adds to the current understanding of single-photon emission computed tomography combined with conventional computed tomography (SPECT-CT) as a diagnostic tool for painful TAR. We hypothesized that SPECT-CT would be predictive of clinical and intraoperative findings and would be more useful than magnetic resonance imaging (MRI) in our cohort.

METHODS

A retrospective review of SPECT-CT imaging performed at our institution in patients with painful TAR from January 2014 to November 2018 was conducted. A total of 37 patients were identified, and 28 of them underwent revision surgery. Additionally, 19 patients had an MRI during the same time frame. Imaging results were compared to the documented clinical findings and intraoperative findings during revision surgery.

RESULTS

Of the 37 patients included, 89.2% (33/37) had SPECT-CT results that were consistent with the ultimate diagnosis documented in the medical record. Aseptic loosening (12/33) and impingement (11/33) were the most common diagnoses. Among patients who underwent revision surgery, SPECT-CT results were consistent with intraoperative findings in 26 of the 28 (92.9%) cases. In the 19 patients who also underwent MRI, the findings were consistent with clinical findings 36.8% (7/19) of the time.

CONCLUSION

In our cohort, there was high consistency between SPECT-CT results and documented clinical diagnoses. SPECT-CT also demonstrated high consistency with intraoperative findings during revision surgery. Compared with MRI, SPECT-CT proved more useful in establishing a diagnosis of pain after TAR.

LEVEL OF EVIDENCE

Level III, comparative series.

Quantitative Analysis of SPECT-CT Data in Metastatic Breast Cancer Patients-The Clinical Significance

Simple Summary

Breast cancer represents one of the most common cancers diagnosed in female patients, with up to 75% of the patients with stage IV breast cancer developing metastatic bone lesions. Early detection of bone metastasis and differentiating them from degenerative lesions using molecular imaging techniques, such as SPECT-CT, is important for therapeutic purposes and patient follow-up. This study was conducted to determine if the quantitative analysis of the data acquired by performing SPECT-CT scans can help in differentiating between metastatic lesions and degenerative bone disease. In 70 female patients, we identified the radiotracer uptake in metastatic and degenerative bone lesions and determined the diagnostic accuracy of the SPECT-CT quantitative analysis in differentiating between the two types of lesions. The results provided valuable information that can improve the diagnostic accuracy of metastatic bone lesions and treatment response evaluation in breast cancer patients.

Abstract

Purpose: To assess the potential added value of the SPECT-CT quantitative analysis in metastatic breast cancer lesions detection and differentiation from degenerative lesions. Methods: This prospective monocentric study was conducted on 70 female patients who underwent SPECT-CT bone scans using ^99mTc–HDP that identified the presence of metastatic bone lesions and degenerative lesions in each patient. Once the lesions were identified, a quantitative analysis of radiotracer uptake was conducted. The highest one to five SUVmax values for both metastatic and degenerative bone lesions were identified in each patient and the data were then statistically analyzed. Results: The SUVmax value was significantly higher in metastatic bone lesions than in degenerative lesions (p < 0.001). The diagnostic accuracy of SPECT-CT quantitative data analysis revealed a sensitivity of 91.5% and a specificity of 93.3% at a cut-off value of the SUVmax of 16.6 g/mL. Conclusion: Quantitative analysis performed using SPECT-CT data can improve the diagnostic accuracy in differentiating between metastatic bone lesions and degenerative lesions, thus leading to appropriate treatment and better follow-up in metastatic breast cancer patients.

Imaging Macrophage Accumulation in a Murine Model of Chronic Pancreatitis with 125I-Iodo-DPA-713 SPECT/CT

Pancreatitis remains a diagnostic challenge in patients with mild to moderate disease, with current imaging modalities being inadequate. Given the prominent macrophage infiltration in chronic pancreatitis, we hypothesized that ¹²⁵I-iodo-DPA-713, a small-molecule radiotracer that specifically targets macrophages, could be used with SPECT/CT to image pancreatic inflammation in a relevant experimental model. Methods: Chronic pancreatitis was induced with cerulein in C57BL/6 mice, which were contrasted with saline-injected control mice. The animals were imaged at 7 wk after induction using N,N-diethyl-2-(2-(3-¹²⁵I-iodo-4-methoxyphenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide (¹²⁵I-iodo-DPA-713) SPECT/CT or ¹⁸F-FDG PET/CT. The biodistribution of ¹²⁵I-iodo-DPA-713 was determined under the same conditions, and a pair of mice was imaged using a fluorescent analog of ¹²⁵I-iodo-DPA-713, DPA-713-IRDye800CW, for correlative histology. Results: Pancreatic ¹²⁵I-iodo-DPA-713 uptake was significantly higher in treated mice than control mice (5.17% ± 1.18% vs. 2.41% ± 0.34% injected dose/g, P = 0.02), as corroborated by imaging. Mice imaged with ¹⁸F-FDG PET/CT showed cerulein-enhanced pancreatic uptake in addition to a moderate signal from healthy pancreas. Near-infrared fluorescence imaging with DPA-713-IRDye800CW showed strong pancreatic uptake, focal liver uptake, and gastrointestinal uptake in the treated mice, whereas the control mice showed only urinary excretion. Ex vivo fluorescence microscopy revealed a large influx of macrophages in the pancreas colocalizing with the retained fluorescent probe in the treated but not the control mice. Conclusion: These data support the application of both ¹²⁵I-iodo-DPA-713 SPECT/CT and DPA-713-IRDye800CW near-infrared fluorescence to delineate pancreatic, liver, or intestinal inflammation in living mice.

Lymphoscintigraphy combined with single-photon emission computed tomography-computed tomography (SPECT-CT): A very effective imaging approach for identification of the site of leak in postoperative chylothorax

Post operative chylothorax is a known complication of various thoracic surgeries. It needs identification of precise site of leak in the thoracic duct. Lymphosicintigraphy can identify chyle leak but cannot delineate exact site of leak. SPECT-CT is precise in anatomic localisation and hence SPECT-CT should be combined with every lymphoscintigraphy in evaluation of clinically suspected case of post operative chylothorax. We report such a case.

Dynamic imaging for CAR-T-cell therapy

Chimaeric antigen receptor (CAR) therapy is entering the mainstream for the treatment of CD19(+)cancers. As is does we learn more about resistance to therapy and the role, risks and management of toxicity. In solid tumour CAR therapy research the route to the clinic is less smooth with a wealth of challenges facing translating this, potentially hugely valuable, therapeutic option for patients. As we strive to understand our successes, and navigate the challenges, having a clear understanding of how adoptively transferred CAR-T-cells behavein vivoand in human trials is invaluable. Harnessing reporter gene imaging to enable detection and tracking of small numbers of CAR-T-cells after adoptive transfer is one way by which we can accomplish this. The compatibility of certain reporter gene systems with tracers available routinely in the clinic makes this approach highly useful for future appraisal of CAR-T-cell success in humans.

Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study

BACKGROUND CONTEXT

The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP.

PURPOSE

To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II).

STUDY DESIGN

A prospective comparative study.

PATIENT SAMPLE

Two hundred patients were enrolled: 96 in Group I and 104 in Group II.

OUTCOME MEASURES

Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records.

METHODS

Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest.

RESULTS

The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this score rises to 7.02, indicative of a high sensitivity.

CONCLUSIONS

Single-photon emission computerized tomography with computerized tomography might have potential in the diagnostic workup of patients with ns CLBP, owing to its higher sensitivity when compared with other advanced medical imaging modalities.

The improved accuracy of planar bone scintigraphy by adding single photon emission computed tomography (SPECT-CT) to detect skeletal metastases from prostate cancer

BACKGROUND

Planar bone scintigraphy (PBS) is a standard radiological technique to detect skeletal metastases from prostate cancer (PC), the addition of SPECT-CT to PBS improves its diagnostic accuracy. The aim of this study was to assess the additional value of targeted SPECT-CT with PBS in detecting skeletal metastasis form prostate cancer, considering resource implications in an Irish hospital setting.

METHODS

54 PC patients with increased radiotracer uptake on PBS were retrospectively recruited from 2012 to 2013. All underwent targeted evaluation with SPECT-CT. PBS and SPECT-CT images were reviewed by two nuclear medicine radiologists and reported independently. The final diagnosis was made based on the CT finding corresponding to the area of radiotracer uptake.

RESULTS

The mean age was 70.9 years (48-88 years) and median PSA at presentation was 13.9 ng/ml (4.2-215 ng/ml). 68.5 % (n = 37) men received treatment for PC while 31.5 % (n = 17) patients had not received treatment prior to PBS. 164 areas of increased radiotracer uptake were identified on PBS; 13 areas were characterised as metastatic on SPECT-CT; iliac bone (n = 3), ribs (n = 1), skull (n = 2), sacrum (n = 1), ischium (n = 1), femur (n = 3), thoracic spine (n = 1) and cervical spine (n = 1). 151 areas were characterised as benign on SPECT-CT. One area of increased radiotracer uptake in the ribs was subsequently described as indeterminate after evaluation with SPECT-CT.

CONCLUSION

SPECT-CT improves the diagnostic accuracy of PBS in detecting skeletal metastasis from PC and is superior to PBS alone in differentiating benign from malignant lesions. Notwithstanding resource implications of increased cost, specialist equipment and specialist manpower hours; we recommend the use of SPECT-CT in conjunction with PBS for targeted evaluation of suspicious bony lesions in this cohort of patients.

Clinical application of SPECT-CT with 99mTc-Tektrotyd in bronchial and thymic neuroendocrine tumors (NETs)

Neuroendocrine tumors (NETs) of the thorax including bronchial and thymic tumors belong to foregut NETs. Limited loco-regional thoracic NETs can be resected with surgery, but in extensive metastatic disease the treatment is mainly palliative. A high incidence and density of somatostatin receptors (SSTR2, SSTR3, and SSTR5) are found in thoracic NETs. The purpose of this study was to evaluate the role of SPECT-CT somatostatin receptor scintigraphy (SRS) with 99mTc-Tektrotyd for imaging, staging and follow up of patients with bronchial and thymic neuroendocrine tumors. Forty-one patients with thoracic tumors with neuroendocrine differentiation were studied. Sixty-eight examinations including SPECT-CT studies of the neck and chest and/or abdomen and pelvis were carried out 2-4 hrs. post i.v. administration of aver-age 740 MBq activity dose of 99mTc-EDDA/HYNIC-TOC (Tektrotyd, Polatom). In all 41 investigated patients we obtained 81.25% (13/16), 88% (22/25) and 85.36% (35/41) of sensitivity, specificity and accuracy of this diagnostic approach, respectively. Somatostatin-receptor scintigraphy correctly identified all primary NETs located in the lungs and thymus. SPECT-CT studies with 99mTc-EDDA/HYNIC-TOC resulted in exact pre-surgical and pre-treatment N/M staging of bronchial and thymic NETs, except 2 cases with multiple hepatic metastases and 1 with massive suprarenal metastasis. It can be concluded that SPECT-CT with 99mTc-EDDA/HYNIC-TOC is a valuable tool for staging and follow-up of patients with thoracic NETs.

Effects of Stimulating Local and Distal Acupoints on Diabetic Gastroparesis: A New Insight in Revealing Acupuncture Therapeutics

One of the most important aspects of clinical acupuncture practice, like diabetic gastroparesis, is the selection of suitable acupoints. Furthermore, it is critical to examine the therapeutic impact differences between distal and local acupoints, as well as the prescription of their combination. In this study, diabetic gastroparesis rats were treated by needling Zhongwan (CV12) and Zusanli (ST36), and then used Single Photon Emission Computed Tomography-CT (SPECT-CT) technology to assess the effects of promoting gastric motility. In addition, morphological observation, immunohistochemical examination, and biomarker assays, such as determination of growth factor 1, motilin, and ghrelin contents in serum samples, were performed to better understand the impact of certain various acupuncture treatments. All of the therapies improved the symptoms of diabetic gastroparesis rats, according to the findings. Stimulating these acupoints, on the other hand, can have a different therapeutic effect. In addition, needling local and distal acupoints together can have an antagonistic or synergistic impact on specific physiological and biochemical indexes such as gastric motility, ghrelin, gastrin, and growth factor 1, among others. Our findings demonstrated the benefits of acupoints and acupuncture in the management of diabetic gastroparesis, as well as a new insight into acupuncture therapeutics.

Precision of SPECT/CT Allows the Diagnosis of a Hidden Brodie's Abscess of the Talus in a Patient with Sickle Cell Disease

Brodie's abscess is a rare subacute osteomyelitis that can be found in sickle cell disease along with other bone complications. A 21-year-old female with sickle cell disease was presenting frequently to the medical casualty department for painful vasoocclusive crises and for persistent ankle pain and swelling. Hybrid imaging with single-photon emission computed tomography-computed tomography (SPECT-CT) incidentally revealed Brodie's abscess in the talus bone of the ankle, causing persisting long-standing pain. SPECT-CT is a modern technology used to scan bone to detect both anatomical and functional abnormalities with high specificity. Brodie's abscess is a rare bone inflammation that could be a hidden cause of pain and infection in sickle cell disease. Although rare, this lesion requires more attention in patients with sickle cell disease because their immunocompromised status renders them prone to this infection.

An Unusual Case of Extraosseous Accumulation of Bone Scan Tracer in a Renal Calculus - Demonstration by SPECT-CT

Extraosseous localization of radioisotope, used in bone scan, in a variety of physiological and pathological conditions is a well-known phenomenon. The causes of extraosseous accumulation of bone-seeking radiotracers should be kept in mind when bone-imaging studies are reviewed to avoid incorrect interpretations. We report an extremely rare occurrence of extraosseous accumulation of bone scintigraphy tracer in a renal calculus, in a patient with adenocarcinoma of prostate, that was demonstrated by Single Photon Emission Computed Tomography and Computed Tomography (SPECT-CT) fusion imaging.

Comparison of Two Different Segmentation Methods on Planar Lung Perfusion Scan with Reference to Quantitative Value on SPECT/CT

PURPOSE

Until now, there was no single standardized regional segmentation method of planar lung perfusion scan. We compared planar scan based two segmentation methods, which are frequently used in the Society of Nuclear Medicine, with reference to the lung perfusion single photon emission computed tomography (SPECT)/computed tomography (CT) derived values in lung cancer patients.

METHODS

Fifty-five lung cancer patients (male:female, 37:18; age, 67.8 ± 10.7 years) were evaluated. The patients underwent planar scan and SPECT/CT after injection of technetium-99 m macroaggregated albumin (Tc-99 m-MAA). The % uptake and predicted postoperative percentage forced expiratory volume in 1 s (ppoFEV1%) derived from both posterior oblique (PO) and anterior posterior (AP) methods were compared with SPECT/CT derived parameters. Concordance analysis, paired comparison, reproducibility analysis and spearman correlation analysis were conducted.

RESULTS

The % uptake derived from PO method showed higher concordance with SPECT/CT derived % uptake in every lobe compared to AP method. Both methods showed significantly different lobar distribution of % uptake compared to SPECT/CT. For the target region, ppoFEV1% measured from PO method showed higher concordance with SPECT/CT, but lower reproducibility compared to AP method. Preliminary data revealed that every method significantly correlated with actual postoperative FEV1%, with SPECT/CT showing the best correlation.

CONCLUSION

The PO method derived values showed better concordance with SPECT/CT compared to the AP method. Both PO and AP methods showed significantly different lobar distribution compared to SPECT/CT. In clinical practice such difference according to different methods and lobes should be considered for more accurate postoperative lung function prediction.

AT1R-Specific Ligand Angiotensin II as a Novel SPECT Agent for Hepatocellular Carcinoma Diagnosis

Hepatocellular carcinoma (HCC) is characterized by a high mortality and early diagnosis and treatment are critically needed. Ang II type 1 receptor (AT1R) has recently emerged as a potential molecular target for cancer diagnosis and intervention. Here, we labeled angiotensin II (Ang II), an AT1R ligand that is overexpressed in various solid cancers, with the near-infrared fluorescent dye, MPA, and radionuclide technetium-99m, and evaluated its capacity for HCC detection. These analyses were done in vitro using HepG2 (AT1R-positive) and BxPC3 (AT1R-negative) cell lines, and in vivo using a subcutaneous and orthotopic xenograft mouse model by fluorescence and SPECT imaging. Both Ang II-PEG₄-MPA- and [^99mTc]Tc-HYNIC-PEG₄-Ang II-bound AT1R exhibited a high affinity in vitro and [^99mTc]Tc-HYNIC-PEG₄-Ang II displayed an acceptable level of in vitro stability in rat plasma and whole blood. In vivo imaging revealed excellent specific tumor-targeting in HepG2 mouse xenografts models. In vitro and in vivo competition experiments revealed specific Ang II-PEG₄-MPA and [^99mTc]Tc-HYNIC-PEG₄-Ang II uptake by HepG2 cells and tumors. Altogether, AT1R-positive tumors were successfully detected via fluorescence and SPECT imaging using Ang II-PEG₄-MPA and [^99mTc]Tc-HYNIC-PEG₄-Ang II, respectively. Given their superior targeting capacity, Ang II-PEG₄-MPA and [^99mTc]Tc-HYNIC-PEG₄-Ang II are promising tools for HCC detection and warrant clinical translation.

Utility of Iodine-131 hybrid SPECT-CT fusion imaging before high-dose radioiodine therapy in papillary thyroid carcinoma

The management protocol for differentiated thyroid cancer includes whole body iodine-131 imaging, to detect residual thyroid tissue and distant metastasis, after thyroidectomy. However, the diagnostic dose of radioiodine may fail to detect the non-functioning or poorly functioning metastasis. We present a case where hybrid single photon-emission computed tomographic and computed tomographic (SPECT-CT) fusion imaging, using a diagnostic dose of iodine-131, was able to detect both functioning as well as non-functioning pulmonary metastases, prior to high-dose radioiodine therapy.

Voriconazole-induced periostitis deformans: serial imaging in a patient with ANCA vasculitis

OBJECTIVES

A 61-year-old with acute granulomatosis and polyangiitis developed Aspergillus fumigatus pneumonia after admission to the intensive care unit with a small bowel perforation. This occurred after immunosuppression (intravenous methylprednisolone, intravenous cyclophosphamide, and plasmapheresis) for his initial presentation with stage 3 acute kidney injury.

MATERIALS AND METHODS

The mycologist recommended long-term treatment with voriconazole after initial recovery.

RESULTS

After 7 months of treatment, the patient complained of joint pain and swelling in his hands. Radiographs, computed tomography, and single-photon emission computed tomography appearances were consistent with periostitis. A diagnosis of Voriconazole-induced periostitis deformans was made and the voriconazole was stopped. Plasma fluoride level was 278 μg/L (normal range < 50 μg/L). Discontinuation of voriconazole led to clinical improvement.

CONCLUSIONS

Periostitis deformans due to fluorosis is a rare complication of voriconazole treatment. The imaging in our case is unusually dramatic. We were able to track the evolution of periosteal reactions over serial imaging.