Diagnostic importance of contrast enhanced (18)F-fluorodeoxyglucose positron emission computed tomography in patients with tumor induced osteomalacia: Our experience

Diagnostic accuracy of 99mTc-HYNIC-TOC SPECT/CT for detecting osteomalacia-associated tumors

OBJECTIVES

Tumor-induced osteomalacia (TIO) is a rare acquired paraneoplastic disorder characterized by hypophosphatemia resulting from tumor-secreted fibroblast growth factor-23 (FGF23). Surgical resection of the culprit TIO is the first choice of treatment. However, TIO is difficult to detect with conventional diagnostic tools due to its small size and variable location in the body. Somatostatin receptor scintigraphy (SSR) has recently emerged as a functional molecular imaging choice for TIO detection and localization. This research was undertaken to evaluate the efficacy of 99mTc-labeled hydrazinonicotinyl-Tyr3-octreotide (99mTc-HYNIC-TOC) SPECT/CT in detecting TIO.

METHODS

99mTc-HYNIC-TOC SPECT/CT and the available clinical data of 25 patients with suspected TIO were analyzed retrospectively. The 99mTc-HYNIC-TOC SPECT/CT findings were compared with the post-surgical pathology diagnosis and clinical follow-up results.

RESULTS

Using 99mTc-HYNIC-TOC SPECT/CT, suspicious tumors were found in 18 of the 25 patients, and 15 of them underwent surgical resection. The post-operative pathology confirmed a TIO in those 13 patients whose symptoms and biochemical anomalies gradually resolved after the surgery. The remaining five patients were finally considered false positives. Moreover, the 99mTc-HYNIC-TOC SPECT/CT results were negative in seven patients, with six patients being true negative (4 patients were diagnosed with acquired Fanconi syndrome and 2 patients responded well to conservative therapy) and one being false negative. Therefore, the sensitivity and specificity values of 99mTc-HYNIC-TOC SPECT/CT in the evaluation of TIO were 92.9% (13/14) and 54.5% (6/11), respectively. The overall accuracy of 99mTc-HYNIC-TOC SPECT/CT for detecting TIO was 76.0% (19/25).

CONCLUSIONS

The 99mTc-HYNIC-TOC SPECT/CT is an accurate imaging modality for locating culprit tumors in TIO.

Global guidance for the recognition, diagnosis, and management of tumor-induced osteomalacia

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by mesenchymal tumors that secrete fibroblast growth factor 23 (FGF23). Patients present with progressive bone pain, muscle weakness, and fragility fractures. TIO is characterized by hypophosphatemia, excess renal phosphate excretion, and low/inappropriately normal 1,25-dihydroxyvitamin D (1,25(OH)₂ D) levels. Rarity and enigmatic clinical presentation of TIO contribute to limited awareness among the medical community. Accordingly, appropriate diagnostic tests may not be requested, leading to delayed diagnosis and poorer patient outcomes. We have developed a global guidance document to improve the knowledge of TIO in the medical community, enabling the recognition of patients with TIO and appropriate referral. We provide recommendations aiding diagnosis, referral, and treatment, helping promote a global standard of patient management. We reviewed the literature and conducted a three-round Delphi survey of TIO experts. Statements were drafted based on published evidence and expert opinions (≥70% consensus required for final recommendations). Serum phosphate should be measured in patients presenting with chronic muscle pain or weakness, fragility fractures, or bone pain. Physical examination should establish features of myopathy and identify masses that could be causative tumors. Priority laboratory evaluations should include urine/serum phosphate and creatinine to assess renal tubular reabsorption of phosphate and TmP/GFR, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D, 1,25(OH)₂ D, and FGF23. Patients with the clinical/biochemical suspicion of TIO should be referred to a specialist for diagnosis confirmation, and functional imaging should be used to localize causative tumor(s). Recommended treatment is tumor resection or, with unresectable/unidentifiable tumors, phosphate salts plus active vitamin D, or burosumab.

Diagnostic utility of Ga-68 DOTA-SSTR and F-18 FDG PET/CT in the detection of culprit tumours causing osteomalacia: a systematic review and meta-analysis

BACKGROUND

Tumour-induced osteomalacia (TIO) or oncogenic osteomalacia is a rare variant of paraneoplastic syndrome secondary to a small benign phosphaturic mesenchymal tumour that secretes phosphaturic substances. Complete tumour excision is often curative. However, the localization of these offending tumours has always remained a challenge because of their small size, slow-growing nature, and presence in atypical locations. We performed a systemic review and meta-analysis on the sensitivity and specificity of F-18 FDG PET/CT and Ga-68 DOTA-SSTR PET/CT to detect tumours causing osteomalacia.

METHODS

Pub Med, SCOPUS, the Cochrane Library and Web of Science were searched for articles on F-18 FDG and Ga-68 DOTA-SSTR PET/CT in the detection of culprit tumours in TIO till September 2020. Both retrospective and prospective studies having three or more patients were included. The methodological quality of included studies was assessed using the Revised Tool for the Quality Assessment of Diagnostic Accuracy Studies-2 checklist. A random-effect model was used for the statistical pooling of sensitivity and specificity. Pooled data were presented with 95% confidence intervals (95% CI) and displayed using Forest plots. Heterogeneity was expressed using the I2 statistic.

RESULTS

The pooled sensitivity of Ga-68 DOTA-SSTR PET/CT in detecting the culprit tumour derived from all included studies is 86% (95% CI: 79-91%). There is moderate statistical heterogeneity among the included studies (I2 = 72.7%). The pooled sensitivity of F-18 FDG PET/CT in detecting the offending tumour derived from all included studies is 73% (95% CI: 61-84%) with moderate statistical heterogeneity among the included studies (I2 = 45.4%).

CONCLUSION

In the detection of offending tumours in TIO, Ga-68 DOTA-SSTR PET/CT has better sensitivity than F-18 FDG PET/CT and should be used as first-line imaging modality due to very high sensitivity.

Comparison of 18 F-FDG PET/CT and 68 Ga-DOTATATE PET/CT in the Targeted Imaging of Culprit Tumors Causing Osteomalacia

Objective

To assess and compare the performance of fluorine‐18‐labeled fluorodeoxyglucose positron emission tomography (¹⁸F‐FDG‐PET/ CT) and gallium‐68‐labeled tetraazacyclododecanetetraacetic acid‐DPhe1‐Tyr3‐octreotate (⁶⁸Ga‐ DOTATATE) PET/CT in the targeted imaging of culprit tumors causing osteomalacia.

Methods

This was a clinical retrospective analysis. We analyzed 13 patients (five men, eight women; mean age, 49 years; range, 19–55 years) with suspicion of tumor‐induced osteomalacia (TIO) between March 2017 and October 2019. All patients underwent two functional imaging methods to locate the culprittumors. Studies were performed on a PET/CT scanner. The injection doses of ¹⁸F‐ FDG and ⁶⁸Ga‐DOTATATE were 0.5mCi/kg and approximately 5.0mCi, respectively. In the two scans, the whole body was captured from head to toe 45 to 60 min after intravenous tracer injection. ⁶⁸Ga‐DOTATATE PET/CT and ¹⁸F‐FDG PET/CT imaging results locate culprit tumors according to the following criteria: (i) abnormal foci uptake concentration was observed locally, and the uptake level was higher than the background level of the right lobe of the liver; (ii) combined CT showed or did not have obvious abnormal density changes; and (iii) non‐specific ingestion lesions due to fracture, arthritis, necrosis of femoral head are excluded. Compared with the results of pathological examination and clinical follow‐up, the sensitivity, specificity and accuracy of ⁶⁸Ga‐DOTATATE PET/CT imaging and ¹⁸F‐FDG PET/CT imaging for TIO were analyzed.

Results

All patients had symptoms of osteomalacia and hypophosphatemia. The lag time (symptoms to PET diagnosis) ranged from 2 to 12 years. There were eight cases of TIO patients and five cases of non‐TIO patients confirmed by surgery, pathology and follow‐up. Among the eight TIO patients, there were six cases (75.0%) of PMTs, one case (12.5%) of giant cell tumor, one case (12.5%) of hemangiopericutoma. Most (n = 6, 75.0%) of the confirmed tumors in our patient population were in the lower extremities, followed by craniofacial regions (n = 1, 12.5%), and torso (n = 1, 12.5%), respectively. Among the five non‐TIO patients, there were two cases of Fanconi syndrome, one case of rickets, and two cases of sporadic osteomalacia hypophosphorus. The culprit tumors could be located either in the bone (n = 5, 62.5%) or the soft tissue (n = 3, 37.5%). ¹⁸F‐FDG PET/CT was able to localize the tumor in six (6/13, 46.1%) patients. ⁶⁸Ga‐DOTATATE PET/CT detected tumor in 8 (83.3%) of 13 patients. The sensitivity of ⁶⁸Ga‐DOTATATE PET/CT imaging and ¹⁸F‐FDG PET/CT imaging in the evaluation of TIO in our patient population were 100% (8/8) vs 75% (6/8). The specificity of the two different methods was 80% (4/5). The overall accuracy was 92.3% (12/13) vs 76.9% (10/13).

Conclusions

⁶⁸Ga‐DOTATATE PET/CT is very effective in assessing hypophosphatemia patients with TIO typical symptoms compared with ¹⁸F‐FDG. Therefore, in clinically suspected cases of hypophosphatemic osteomalacia, ⁶⁸Ga‐DOTATATE PET/CT should be preferred as an imaging modality investigation to avoid delay in the treatment of this disease.

Performance of 68Ga-DOTA-SST PET/CT, octreoscan SPECT/CT and 18F-FDG PET/CT in the detection of culprit tumors causing osteomalacia: a meta-analysis

Objectives

The objective of this study was to assess and compare the performance of ⁶⁸Ga-DOTA-conjugated-somatostatin-receptor-targeting-peptides (⁶⁸Ga-DOTA-SST) PET/CT, octreoscan-SPECT/CT and ¹⁸F-FDG-PET/CT in the detection of tumor-induced osteomalacia (TIO).

Methods

Relevant studies reporting the performance ⁶⁸Ga-DOTA-SST PET/CT, octreoscan-SPECT/CT and ¹⁸F-FDG-PET/CT in TIO were identified by searching PubMed, EMBASE, and Web of Science (last updated June 2019). Two authors independently extracted the numbers of true and false positives, and true and false negatives. The pooled estimates on a per-patient basis were calculated with 95% confidence interval (CI) obtained using a random-effects model.

Results

Fourteen studies comprising 346 patients were included in this meta-analysis. The meta-analysis provided the following results on a per-patient analysis. The pooled sensitivities of both ⁶⁸Ga-DOTA-SST PET/CT (90%, 95% CI 82–95%) and octreoscan-SPECT/CT (83%, 95% CI 75–89%) were found to be significantly higher (P < 0.005) than that of ¹⁸F-FDG PET/CT (67%, 95% CI 53–80%). There was no statistically significant difference between the sensitivity of ⁶⁸Ga-DOTA-SST PET/CT and octreoscan-SPECT/CT (P = 0.161). Owing to the low number of articles with true negative findings, the pooled specificities were not calculated. A total of 287 tumors were identified in 287 patients according to the data the included studies offered. The majority of the tumors were located in the lower extremities (59.6%, 171/287), followed by craniofacial regions (24.0%, 69/287), torso (9.4%%, 27/287), and upper extremities (6.9%, 20/287).

Conclusion

This meta-analysis demonstrates that somatostatin receptor-based imaging modalities outperformed ¹⁸F-FDG PET/CT in the detection of TIO, with ⁶⁸Ga-DOTA-SST PET/CT performing slightly better than octreoscan-SPECT/CT.

Imaging Examination and Quantitative Detection and Analysis of Gastrointestinal Diseases Based on Data Mining Technology

The medical image storage and transmission system completes the collection, storage, management, diagnosis and information processing of digital medical image information generated from digital medical devices, accumulates a large amount of data resources, and uses these valuable data resources to extract corresponding diseases. Diagnostic rules that help improve the accuracy of clinical disease diagnosis have always been the subject of medical research and management. Gastrointestinal diseases are common high-risk digestive diseases. This paper studies the imaging detection and quantitative detection and analysis of gastrointestinal diseases based on data mining, aiming to improve the accuracy of doctors' clinical diagnosis, reduce the misdiagnosis and misdiagnosis of patients' diseases, and reduce the burden on patients. With the high computing speed and computational accuracy of the computer, combined with the flexible analysis and judgment ability of the human body, the doctor can help the semi-structured and unstructured diagnosis problems. Experiments demonstrate the effectiveness and robustness of the proposed method.