The Value of Preoperative Imaging in Small Bowel Neuroendocrine Tumors

Background

Neuroendocrine tumors of the small bowel (SBNETs) are a rare but important subgroup of malignancies. Since 30 % of SBNETs present with metastatic disease, often with an occult primary, preoperative imaging is critical for determining who will benefit most from abdominal exploration. We set out to evaluate the usefulness of the two most commonly performed imaging modalities in predicting the extent of disease found at exploration in patients with SBNETs.

Methods

A retrospective chart review was performed on patients with SBNETs resected at 1 institution. Data from preoperative computed tomography (CT) scans were reviewed to determine whether the primary tumor, nodal, or liver metastases were seen, then compared with intraoperative findings. Results of preoperative somatostatin receptor scintigraphy (SRS) were similarly examined.

Results

A total of 62 patients with SBNETs were included. Of these patients, 42 of 62 (68 %) had distant metastases and 48 of 62 (77 %) had nodal metastases at exploration. A total of 56 patients had preoperative CT scans and 47 had SRS. Using CT, a primary tumor was localized to the small bowel in 27 of 56 (48 %) and nodal metastases seen in 33 of 56 (79 %) of cases. SRS found intra-abdominal uptake in 35 of 47 cases (74 %).

Conclusions

CT and SRS are complementary in making the diagnosis of SBNET, with CT giving more precise anatomical detail, while SRS helps to confirm that lesions are NETs and is useful for identifying occult extrahepatic sites of metastatic disease. However, 10–15 % of SBNETs were not identified by either test preoperatively, and therefore surgical exploration still plays an important role in making the diagnosis in these patients.     

Accuracy of MRI and <Superscript>18</Superscript>F-FDG PET/CT for Restaging After Preoperative Concurrent Chemoradiotherapy for Rectal Cancer

Background  

Performing a restaging work-up with magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) can provide information about the effects that are related to preoperative concurrent chemoradiotherapy (CCRT). The purpose of the present study was to investigate the accuracy of MRI and ¹⁸F-FDG PET/CT for restaging after preoperative CCRT for rectal cancer.     

<Superscript>99m</Superscript>Tc-HDP bone scintigraphy and <Superscript>18</Superscript>F-sodiumfluoride PET/CT in primary staging of patients with prostate cancer

Introduction/Aim

Correct staging of patients with prostate cancer is important for treatment planning and prognosis. Although bone scintigraphy with ^99mTc-phosphonates (BS) is generally advised for staging by guidelines in high risk prostate cancer, this imaging technique is hampered by a high rate of inconclusive results and moderate accuracy. Potentially better imaging techniques for detection of bone metastases such as ¹⁸F-sodiumfluoride PET/CT (NaF PET/CT) are therefore being evaluated. In this observational cohort study we evaluate the performance and clinical impact of both BS and NaF PET/CT in primary staging of patients with prostate cancer.

Methods

The first of two cohorts consisted of patients who received a BS while the second included patients who received a NaF PET/CT for primary staging of prostate cancer. For both cohorts the number of positive, negative and equivocal findings, calculated diagnostic performance of the imaging modality in terms of sensitivity and specificity, as well as the impact on clinical management were studied. The ranges of the diagnostic performance were calculated both assuming that equivocal findings were positive and assuming that they were negative for bone metastases. For the NaF PET/CT cohort the number of patients with signs of lymph node metastases on low dose CT were also recorded, including the impact of these findings on clinical management.

Results

One-hundred-and-four patients underwent NaF PET/CT, whereas 122 patients underwent BS. Sensitivities of 97–100 and 84–95% and specificities of 98–100 and 72–100% were found on a patient basis for detection of bone metastases with NaF PET/CT and BS, respectively. Equivocal findings warranted further diagnostic procedures in 2% of the patients in the NaF cohort and in 16% in the BS cohort. In addition NaF PET/CT demonstrated lymph node metastases in 50% of the included patients, of which 25% showed evidence of lymph node metastases only.

Conclusion

Our data indicate better diagnostic performance of NaF PET/CT compared to BS for detection of bone metastases in primary staging of prostate cancer patients. Less equivocal findings are encountered with NaF PET/CT. Moreover, NaF PET/CT has additional value over BS since lymph node metastases are encountered frequently.

     

The Distal Predilection of Small Bowel Neuroendocrine Tumors

Background

The small bowel (SB) is the most common site of neuroendocrine tumors (NETs) of the GI tract. These are described as being predominantly jejunoileal, but their exact locations within the SB have not been well defined. We sought to determine prospectively the spectrum of SBNET locations.

Methods

Patients undergoing exploration for SBNET primaries had measurement of bowel length, tumor locations, and resection length recorded. Correlations of clinicopathologic factors were performed, and analysis done utilizing Welch’s t test, Chi square test, and the Kaplan–Meier method.

Results

Measurements were recorded in 123 patients, 107 of whom had complete information. Multifocal tumors (MTs) were found in 69 (56%) and unifocal (UTs) in 54 (44%) patients. Only 1 of 107 patients had a tumor within 100 cm of the ligament of Treitz (LT), whereas 77 of 107 (72%) had tumors within 100 cm of the ileocecal valve (ICV). No MTs were found within 100 cm of LT, whereas 41 of 60 (68%) patients had all (10) or at least one tumor (31) located within 100 cm of the ICV. MTs required a mean resection length of 108 versus 59 cm for UTs (p?<?0.01). Seventy-seven percent of UTs (36/47) were within 100 cm of ICV. Tumors occurring only between?>?100 cm from the LT and ICV were seen in 29 of 107 (27%) patients.

Conclusions

SBNETs are frequently multifocal and most commonly located within 100 cm of the ICV. SBNETs are less prevalent proximally in the small bowel, which may result from anatomic differences in enterochromaffin cell density, hormonal factors, or environmental exposures in the distal SB.

     

Comparison of Uptake Characteristics and Prognostic Value of <Superscript>201</Superscript>Tl and <Superscript>18</Superscript>F-FDG in Esophageal Cancer

Background Patients with esophageal cancer often undergo ²⁰¹Tl myocardial imaging for preoperative risk evaluation, thereby providing an excellent opportunity to assess tumor handling of ²⁰¹Tl. We thus compared the characteristics of ²⁰¹Tl and ¹⁸F-FDG uptake by esophageal cancer and further investigated their prognostic values. Methods The study included 100 newly diagnosed esophageal cancer patients who underwent preoperative ²⁰¹Tl SPECT and ¹⁸F-FDG PET exams. Tumor to mediastinal uptake (T/M) ratio and retention index (RI) of ²⁰¹Tl, tumor ¹⁸F-FDG pSUV, tumor size, location, and stage were assessed. Survival analysis was performed for disease-free survival using the Kaplan–Meier method. Cox proportional hazard models were used to determine independent risk factors. Results ²⁰¹Tl SPECT and ¹⁸F-FDG PET visualized the primary tumor in 85/100 (85.0%) and 91/100 (91.0%) patients, respectively (p = 0.03). There were close correlations between early and delayed ²⁰¹Tl T/M ratios (r = 0.83, p < 0.0001) and between T/M ratios and ¹⁸F-FDG pSUV (r = 0.56 and 0.57, respectively, both p < 0.0001). Both T/M ratios and ¹⁸F-FDG pSUV correlated significantly with tumor stage (ρ = 0.45, 0.40, and 0.59, respectively, all p < 0.0001). Survival analysis revealed tumor size, ²⁰¹Tl negative tumors, ¹⁸F-FDG negative tumors, delayed ²⁰¹Tl T/M ratio, RI, stage, and ¹⁸F-FDG pSUV to be significant univariate predictors for disease-free survival. Multivariate survival analysis showed stage (p = 0.02) to be a significant independent prognostic predictor. Conclusions In patients with esophageal cancer, assessment of tumor ²⁰¹Tl uptake, as with ¹⁸F-FDG, may provide potentially useful information regarding tumor characteristics. Presented in part at the 51st Annual Meeting of the Society of Nuclear Medicine, Philadelphia, PA, USA, June 19–23, 2004.     

A Multimodal Imaging Protocol, <Superscript>123</Superscript>I/<Superscript>99</Superscript>Tc-Sestamibi,SPECT, and SPECT/CT,in Primary Hyperparathyroidism Adds Limited Benefit for Preoperative Localization

Introduction

Focused parathyroidectomy in primary hyperparathyroidism (1°HPT) is possible with accurate preoperative localization and intraoperative PTH monitoring (IOPTH). The added benefit of multimodal imaging techniques for operative success is unknown.

Method

Patients with 1°HPT, who underwent parathyroidectomy in 2012–2014 at a single institution, were retrospectively reviewed. Only the patients who underwent the standardized multimodal imaging workup consisting of ¹²³I/⁹⁹Tc-sestamibi subtraction scintigraphy, SPECT, and SPECT/CT were assessed.

Results

Of 360 patients who were identified, a curative operation was performed in 96 %, using pre-operative imaging and IOPTH. Imaging analysis showed that ¹²³I/⁹⁹Tc-sestamibi had a sensitivity of 86 % (95 % CI 82–90 %), positive predictive value (PPV) 93 %, and accuracy 81 %, based on correct lateralization. SPECT had a sensitivity of 77 % (95 % CI 72–82 %), PPV 92 % and accuracy 72 %. SPECT/CT had a sensitivity of 75 % (95 % CI 70–80 %), PPV of 94 %, and accuracy 71 %. There were 3 of 45 (7 %) patients with negative sestamibi imaging that had an accurate SPECT and SPECT/CT. Of 312 patients (87 %) with positive uptake on sestamibi (93 % true positive, 7 % false positive), concordant findings were present in 86 % SPECT and 84 % SPECT/CT. In cases where imaging modalities were discordant, but at least one method was true-positive, ¹²³I/⁹⁹Tc-sestamibi was significantly better than both SPECT and SPECT/CT (p < 0.001). The inclusion of SPECT and SPECT/CT in 1°HPT imaging protocol increases patient cost up to 2.4-fold.

Conclusion

¹²³I/⁹⁹Tc-sestamibi subtraction imaging is highly sensitive for preoperative localization in 1°HPT. SPECT and SPECT/CT are commonly concordant with ¹²³I/⁹⁹Tc-sestamibi and rarely increase the sensitivity. Routine inclusion of multimodality imaging technique adds minimal clinical benefit but increases cost to patient in high-volume setting.

     

Dual-Time <Superscript>18</Superscript>F-FDG PET/CT Imaging in Initial Locoregional Staging of Breast Carcinoma: Comparison with Conventional Imaging and Pathological Prognostic Factors

The aims of this retrospective study were to consider the diagnostic role of dual-time ¹⁸F-fluorodeoxyglucose positron emission tomography and computed tomography (¹⁸F-FDG PET/CT) in detection of breast carcinoma and axillary lymph node (ALN) status and to evaluate the primary tumor ¹⁸F-FDG uptake pattern. Preoperative staging was performed by ¹⁸F-FDG PET/CT in 78 female patients with breast carcinoma. Conventional imaging results were evaluated by breast magnetic resonance imaging (MRI) of 79 lesions in 78 patients, bilateral mammography (MMG) of 40 lesions in 40 patients, and breast ultrasonography (USG) of 47 lesions in 46 patients. The primary tumor detection rate using ¹⁸F-FDG PET/CT was higher than those using MRI, USG, and MMG. The sensitivity and specificity of ¹⁸F-FDG PET/CT scans for detecting multifocality were higher than those of MRI. The specificity of ALN metastasis detection with MRI was higher than that with ¹⁸F-FDG PET/CT, but ¹⁸F-FDG PET/CT had higher sensitivity. Higher ¹⁸F-FDG uptake levels were detected in patients with ALN metastasis, histologic grade 3, estrogen–progesterone-negative receptor status, lymphatic invasion, and moderate to poor prognostic groups. There was no statistical difference for the retention index in categorical pathological parameters except for progesterone-negative status. In conclusion, ¹⁸F-FDG PET/CT scans may be a valuable imaging technique for evaluating primary tumor and axillary status in staging breast carcinoma and ¹⁸F-FDG uptake may be a prognostic factor that indicates aggressive tumor biology and poor prognosis. Dual-time imaging in breast carcinoma staging may not be used for predicting pathological criteria and the aggressiveness of primary lesions.     

Prognostic value of post-treatment metabolic tumor volume from <Superscript>11</Superscript>C-methionine PET/CT in recurrent malignant glioma

We investigated the diagnostic and prognostic significance of metabolic parameters from ¹¹C-methionine (MET) positron emission tomography (PET) in patients with malignant glioma. The MET-PET was examined in 42 patients who had been previously treated with adjuvant treatment for malignant glioma. Both ratios of maximal MET uptake of the tumors to those of the contralateral normal gray matter (T/N ratio) and metabolic tumor volume (MTV) were estimated in each lesion. The diagnostic performance for recurrence was investigated in all enrolled patients. A definitive diagnosis was done with pathologic confirmation or clinical follow-up. Among recurrent patients, we evaluated the prognostic value of metabolic parameters (T/N ratio and MTV) as well as clinical factors. Among 42 patients, 35 patients were revealed with recurrence. Both T/N ratios (p?=?0.009) and MTV (p?=?0.001) exhibited statistical significance to differentiate between recurrence and post-treatment radiation effect. A T/N ratio of 1.43 provided the best sensitivity and specificity for recurrence (91.4 and 100 %, respectively), and a MTV of 6.72 cm³ provided the best sensitivity and specificity (77.1 % and 100 %, respectively). To evaluate the prognostic impact, different cutoffs of MTV were examined in patients with recurrent tumor and a threshold of 60 cm³ was determined as a best cutoff value to separate the patients in two prognostic groups. Univariate analysis revealed improved overall survival (OS) for patients with Karnofsky performance scale (KPS) score ≥70 (p?<?0.001) or MTV <60 cm³ (p?=?0.049). Multivariate analysis showed that patients with KPS score ≥70 (p?<?0.001; hazard ratio?=?0.104; 95 % CI, 0.029–0.371) or MTV?<?60 cm³ (p?=?0.031; hazard ratio?=?0.288; 95 % CI, 0.093–0.895) were significantly associated with a longer OS. However, T/N ratio was not correlated with patients’ outcome. Metabolic parameters had the diagnostic value to differentiate recurrence from post-treatment radiation effect. Compared with T/N ratio, MTV was an independent significant prognostic factor with KPS score in patients with recurrent tumor. Our study had a potential to manage these patients according to prognostic information using MET-PET.     

<Superscript>131</Superscript>I-Meta-iodobenzylguanidine in the Management of Metastatic Midgut Carcinoid Tumors

The management of metastatic neuroendocrine tumors incorporates multimodal therapy with surgery, biotherapy, and chemotherapy. Tumor-targeted therapies using radiolabeled octreotide and meta-iodobenzylguanidine (mIBG) represent a novel treatment approach. The aim of this study was to evaluate the effectiveness of ¹³¹I-mIBG in the treatment of metastatic midgut carcinoid tumors. survival outcomes were assessed for patients treated at two regional cancer centers and then compared. One center used ¹³¹I-mIBG routinely in the management of metastatic carcinoid tumors (center A), and the other did not use this modality (center B). Only patients with histologically proven metastatic carcinoid tumor shown, or thought most likely, to be of midgut origin were included in the study. During the period 1980 to 2002, a series of 58 patients from center A with metastatic carcinoid tumor arising from the midgut underwent multimodality therapy with the addition of ¹³¹I-mIBG. Their median age was 64 years. The median dose of ¹³¹I-mIBG administered was 6751 MBq, and there was an average of 2.8 treatments per patient. During the same period, 58 patients with metastatic carcinoid were treated at center B with similar multimodality therapy without the use of ¹³¹I-mIBG therapy. Their median age was 65 years. Survivals at 3 and 5 years were 77% and 63%, respectively (95% CI 47–75), for group A. The 3- and 5-year survivals for group B were 56% and 47% (95% CI 34–59), respectively. The mean follow-up was 6.6 years for group A and 5.0 years for group B. Although retrospective in nature, this study suggests that the addition of ¹³¹I-mIBG therapy to the treatment protocol of patients with metastatic midgut carcinoid tumors prolongs survival.This article was presented at the International Association of Endocrine Surgeons meeting, Uppsala, Sweden, June 14–17, 2004.     

[<Superscript>11</Superscript>C]choline PET/CT in prostate cancer patients with biochemical recurrence after radical prostatectomy

Objective  

To evaluate [¹¹C]choline positron emission tomography/computed tomography ([¹¹C]choline PET/CT) for the detection of a biochemical recurrence of prostate cancer after radical prostatectomy.     

Combined [<Superscript>18</Superscript>F]Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography (FDG-PET/CT) for Detection of Recurrent, <Superscript>131</Superscript>I-Negative Thyroid Cancer

Background Whole-body ¹³¹I scintigraphy (WBS) and serial thyroglobulin measurement (Tg) are standard methods for detecting thyroid cancer recurrence after total/near total thyroidectomy and ¹³¹I ablation. Some patients develop elevated Tg (Tg-positive) or there is clinical suspicion of recurrence, but WBS are negative (WBS-negative). This may reflect non-iodine-avid recurrence or metastasis. In 2002, the Centers for Medicare and Medicaid Services (CMS) approved positron emission tomography with [¹⁸F]fluorodeoxyglucose (FDG-PET) for Tg-positive/WBS-negative patients with follicular-cell-origin thyroid cancer. Limited data are available regarding the performance of combined FDG-PET/computed tomography (FDG-PET/CT) for detecting recurrent thyroid cancer in WBS-neg patients. Methods This retrospective review of prospectively collected data analyzed 65 patients who had FDG-PET/CT for suspected thyroid cancer recurrence (April 1998–August 2006). Patients were WBS-negative but were suspected to have recurrence based on Tg levels or clinical grounds. Suspected FDG-PET/CT abnormalities were reported as benign or malignant. Lesions were ultimately declared benign or malignant by surgical pathology or clinical outcome (disease progression). Results Of 65 patients who underwent FDG-PET/CT, 47 had positive FDG-PET/CT. Of the positive FDG-PET/CT, 43 studies were true positives, with 21 (49%) confirmed pathologically by surgical resection. The four false positives (3/4 confirmed pathologically) included an infundibular cyst, an inflamed supraclavicular cyst, pneumonitis, and degenerative disc disease. Of the 18 FDG-PET/CT studies that were negative, 17 were true negatives and one was a false negative (metastatic papillary carcinoma). Thus, FDG-PET/CT demonstrated a patient-based sensitivity of 98%, specificity of 81%, positive predictive value of 91%, and negative predictive value of 94%. Conclusions FDG-PET/CT is useful for detecting thyroid cancer recurrence in WBS-negative patients, and can assist decision making.     

Evolving Role of Molecular Imaging with <Superscript>18</Superscript>F-Sodium Fluoride PET as a Biomarker for Calcium Metabolism

¹⁸F-sodium fluoride (NaF) as an imaging tracer portrays calcium metabolic activity either in the osseous structures or in soft tissue. Currently, clinical use of NaF-PET is confined to detecting metastasis to the bone, but this approach reveals indirect evidence for disease activity and will have limited use in the future in favor of more direct approaches that visualize cancer cells in the read marrow where they reside. This has proven to be the case with FDG-PET imaging in most cancers. However, a variety of studies support the application of NaF-PET to assess benign osseous diseases. In particular, bone turnover can be measured from NaF uptake to diagnose osteoporosis. Several studies have evaluated the efficacy of bisphosphonates and their lasting effects as treatment for osteoporosis using bone turnover measured by NaF-PET. Additionally, NaF uptake in vessels tracks calcification in the plaques at the molecular level, which is relevant to coronary artery disease. Also, NaF-PET imaging of diseased joints is able to project disease progression in osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis. Further studies suggest potential use of NaF-PET in domains such as back pain, osteosarcoma, stress-related fracture, and bisphosphonate-induced osteonecrosis of the jaw. The critical role of NaF-PET in disease detection and characterization of many musculoskeletal disorders has been clearly demonstrated in the literature, and these methods will become more widespread in the future. The data from PET imaging are quantitative in nature, and as such, it adds a major dimension to assessing disease activity.     

Relationship Between <Superscript>18</Superscript>F-fluorodeoxyglucose Accumulation and the <Emphasis Type="Italic">BRAF</Emphasis><Superscript>V600E</Superscript> Mutation in Papillary Thyroid Cancer

Background

To determine whether ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG)-PET/CT is useful for predicting the BRAF ^V600E mutation status of a primary papillary thyroid carcinoma (PTC).

Methods

A retrospective analysis was performed in 108 patients who underwent ¹⁸F-FDG positron emission tomography–computed tomography (PET/CT) for staging before thyroidectomy and BRAF analysis in biopsy-confirmed PTC. The maximum standardized uptake value (SUV_max) of the primary tumor was calculated according to FDG accumulation. Univariate and multivariate analyses were performed to assess the association between the SUV_max and clinicopathological variables.

Results

The BRAF ^V600E mutation was detected in 71 of 108 (65.7%) patients. In all subjects, the tumor size and BRAF ^V600E mutation were independently related to the SUV_max according to multivariate analyses (P = 0.002 and 0.007, respectively). The SUV_max was significantly higher in tumors with the BRAF ^V600E mutation than in tumors with wild-type BRAF (10.24 ± 11.89 versus 4.02 ± 3.86; P = 0.007). In the tumor size >1 cm subgroup, the BRAF ^V600E mutation was the only factor significantly associated with the SUV_max (P = 0.016). A SUV_max cutoff level of 4.9 was determined to be significant for predicting the BRAF ^V600E mutation status (sensitivity 77.4%, specificity 100.0%, area under the curve 0.929; P < 0.0001) according to ROC curve analysis.

Conclusions

The BRAF ^V600E mutation is independently associated with high ¹⁸F-FDG uptake in PTC, especially in those with a tumor size >1 cm.

     

Prognostic Value of Metabolic Tumor Volume Measured by <Superscript>18</Superscript>F-Fluorodeoxyglucose Positron Emission Tomography in Patients with Esophageal Carcinoma

Purpose  

The aim of this study was to evaluate the prognostic value of metabolic tumor volume (MTV) measured by ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in patients with esophageal carcinoma.     

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

ObjectiveTo 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.MethodsThis 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.ResultsAll 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.     

18F-FDG PET/CT结肠空气造影在结肠病变应用中的诊断价值

【摘要】 目的 探讨18F-FDG PET/CT结肠空气造影术对结肠病变的诊断效能。方法 临床连续纳入70例怀疑结肠息肉（肿瘤）的患者及常规PET/CT检查发现肠道局灶性浓聚患者。患者注射18F-FDG（0.1mCi/Kg）60分钟后进行第一次非造影扫描。扫描结束后,行结肠空气造影扫描。所有患者行电子纤维肠镜检查,非造影扫描及空气造影扫描图像影像诊断均分别与电子纤维肠镜作为金标准进行统计,分析18F-FDG PET/CT结肠空气造影检查对结肠息肉、结肠肿瘤的灵敏度、特异度。结果70例患者电子肠镜共发现23处恶性肿瘤病灶,15处息肉等良性病灶,其中常规PET/CT对恶性肿瘤的诊断灵敏度为86.96%,对息肉的诊断诊断灵敏度为46.67%。结肠空气造影PET/CT对恶性肿瘤的诊断灵敏度为95.65%（22/23）,对良性息肉的诊断灵敏度为86.67% （13/15）。11个息肉在造影后显示病灶形态更为清晰（73.33%）。1例患者造影后显示肠道内瘘清晰。23例患者在结肠空气造影PET/CT检查后对常规PET/CT检查报告做出了较大修改,占32.86%（23/70）。结论18F-FDG PET/CT结肠空气造影检查能提高结肠良性息肉的检出灵敏度,能较好的鉴别生理性浓聚,提高诊断特异度;18F-FDG PET/CT结肠造影空气检查对显示病灶的形态、大小及肿瘤侵犯转移情况优于非造影检查,18F-FDG PET/CT结肠造影空气检查可以作为常规PET/CT扫描检查的重要补充方法。     

Value of <Superscript>123</Superscript>I-Subtraction and Single-Photon Emission Computed Tomography in Addition to Planar <Superscript>99m</Superscript>Tc-MIBI Scintigraphy Before Parathyroid Surgery

Purpose To find out if single-photon emission computed tomography (SPECT) and ¹²³I-subtraction can enhance the findings of ^99mTc-methoxyisobutylisonitrile (MIBI) scintigraphy for the preoperative localization of parathyroid (PT) tumors. Methods Among the 111 consecutive patients who underwent preoperative planar ^99mTc-MIBI scintigraphy for hyperparathyroidism (HPT), 64 underwent delayed SPECT, and 17 underwent ¹²³I-subtraction. Two independent blinded experts scored the topographical localization, diagnostic confidence, and impact of each diagnostic modality on the surgical strategy. Results For adenomas, ^99mTc-MIBI scintigraphy had a sensitivity of 77% with a positive predictive value (PPV) of 83%. SPECT did not affect the sensitivity or PPV, but it increased the diagnostic confidence and changed the surgical strategy in 21% of the patients. ¹²³I-subtraction increased the sensitivity from 64% to 82%, but decreased the PPV from 88% to 82%. In hyperplastic glands, ^99mTc-MIBI scintigraphy had a sensitivity of 47% and a PPV of 95%. When ^99mTc-MIBI scintigraphy was combined with SPECT and ¹²³I-subtraction, the results were 44%/10% and 52%/92%, respectively. Both SPECT and ¹²³I-subtraction decreased the diagnostic confidence. Conclusions Adding SPECT to ^99mTc-MIBI scintigraphy improved the surgical decision for parathyroid adenomas. The addition of ¹²³I-subtraction was of limited value. For hyperplastic glands, ^99mTc-MIBI scintigraphy was relatively ineffective, even with the addition of SPECT or ¹²³I-subtraction.     

Unexpected Benefit of the Positron Emission Tomography/Computed Tomography Using <Superscript>18</Superscript>F-Fluorodeoxyglucose: Report of a Case

The positron emission tomography/computed tomography (PET/CT) has been a new tool utilized in the diagnosis and staging of various cancers. However, common worldwide utilization of the PET/CT includes some economic, legal, and ethic controversies. Although PET/CT scanning can detect colorectal premalignant lesions in an early treatable stage, most governments’ health care system does not pay for it as a screening test because of its economic burden. Thus, people are forced to make vital decisions about their health because of health policies of their governments. Here, we present an unusual case and discuss the utilization of PET/CT for detection of incidental neoplasms.     

Solid-State Quantitative <Superscript>1</Superscript>H and <Superscript>31</Superscript>P MRI of Cortical Bone in Humans

Magnetic resonance imaging (MRI) plays a pivotal role for assessment of the musculoskeletal system. It is currently the clinical modality of choice for evaluation of soft tissues including cartilage, ligaments, tendons, muscle, and bone marrow. By comparison, the study of calcified tissue by MRI is still in its infancy. In this article, we review the potential of the modality for assessment of cortical bone properties known to be affected in degenerative bone disease, with focus on parameters related to matrix and mineral densities, and porosity, by means of emerging solid-state ¹H and ³¹P MRI techniques. In contrast to soft tissues, the MRI signal in calcified tissues has very short lifetime, on the order of 100 μs to a few milliseconds, demanding customized imaging approaches that allow capture of the signal almost immediately after excitation. The technologies described are suited for quantitatively imaging human cortical bone in specimens as well as in vivo in patients on standard clinical imagers, yielding either concentrations in absolute units when measured against a reference standard, or more simply, in the form of surrogate biomarkers. The two major water fractions in cortical bone are those of collagen-bound and pore water occurring at an approximately 3:1 ratio. Collagen-bound water density provides a direct quantitative measure of osteoid density. While at an earlier stage of development, quantification of mineral phosphorus by ³¹P MRI yields mineral density and, together with knowledge of matrix density, should allow quantification of the degree of bone mineralization.