Antigranulocyte scintigraphy in infected hip prosthesis: the diagnostic importance of delayed 20-24-h imaging and semiquantitative analysis

AIM: To evaluate clinical efficacy of a dual-time acquisition protocol, which included 4 and 20/24-h imaging with antigranulocyte antibody scintigraphy (LeukoScan) combined with semiquantitative analysis in the diagnosis of infection in painful hip prosthesis. METHODS: Sixty-seven consecutive patients with hip prosthesis were enrolled in this research project: 35 females, 32 males, mean age of 56.3 years. All patients had clinical and biochemical suspicious of infection. Each prosthesis had been implanted 3 months to 12 years before enrollment in this study. Twenty-four patients were on antibiotic therapy at the time of scintigraphy. Seven patients had bilateral hip prosthesis, one painful and the other painless: the seven painless prostheses were considered controls. LeukoScan examination was performed both at early (4 h) and delayed (20/24 h) times. The scintigraphic data were assessed both by visual and semiquantitative methods by three experienced nuclear medicine physicians blinded to clinical, laboratory and radiographic results. The uptake was graded visually by a 4-point scale: intense=3, moderate=2, mild=1 and absent=0. The semiquantitative analysis was obtained by a region of interest (ROI) analysis used in the anterior views to measure the ratio between the mean radioactivity in the prosthesis and the background radioactivity in the early and delayed images. An increase in the intensity of uptake of at least one scale-step at visual analysis and 20% at semiquantitative ROI analysis at the dual-time (early vs. delayed) LeukoScan was considered consistent with infection, whereas a stable or decreasing pattern was judged a negative result. Three-phase 99mTc-hydroxymethane diphosphonate bone scan was also performed routinely. Final diagnosis was determined at surgery and/or long-term clinical and imaging follow-up. RESULTS: At visual analysis, sensitivity for both early and delayed imaging was 94%, whereas specificity was 71% for early imaging and 83% for early and delayed imaging approach. At semiquantitative ROI analysis, sensitivity remained 94%, whereas specificity rose slightly to 73% for early imaging and to 90% for early and delayed imaging combined. Of note, four false-positive early scans were diagnosed correctly as negative on delayed imaging showing a decreasing pattern in uptake intensity. Sensitivity and specificity were similar whether patients were on or off antibiotic therapy. CONCLUSION: Our data show that early imaging LeukoScan is highly sensitive in evaluating septic prosthesis, but it is not optimally specific. Although the dual-time LeukoScan is capable of significantly increasing specificity for detecting infection. The semiquantitative ROI analysis further increased the specificity. Concomitant antibiotic treatment did not seem to influence the diagnostic efficacy of LeukoScan scintigraphy in detecting infected hip prosthesis.     

Role of anti-granulocyte Fab' fragment antibody scintigraphy (LeukoScan) in evaluating bone infection: acquisition protocol, interpretation criteria and clinical results

Scintigraphy using anti-granulocyte Fab' fragment (LeukoScan) was performed in a series of 220 consecutive patients with suspected bone infection referred to our centre between September 1999 and June 2002. Two protocols were compared for interpreting scans: (1) evaluation of early 4 h imaging alone (protocol A), and (2) evaluation both of early and delayed 24 h imaging (protocol B). Protocol A and protocol B showed equal values of sensitivity (91.9% in patients with diabetic foot and 84.2% in patients with joint prosthesis/peripheral bone implants). Conversely, specificity was higher adopting protocol B than protocol A: 87.5% vs 75.0% in patients with diabetic foot, and 85.7% vs 76.2% in patients with joint prosthesis/peripheral bone implants, respectively. In particular, an improvement in specificity using protocol B was found in those patients with infection and with only a mild LeukoScan uptake in the early 4 h imaging: in these patients an increasing uptake intensity pattern observed in the delayed 24 h imaging was indicative of infection while a decreasing pattern suggested a negative result. Instead, the evidence of a high uptake intensity in the early LeukoScan imaging was a strong indicator of infection and delayed imaging in these cases did not further improve specificity. In conclusion, in our experience, LeukoScan showed high sensitivity in diagnosing bone infection in patients with diabetic foot and joint prosthesis or other peripheral bone implants. Moreover, in patients with an early high LeukoScan uptake intensity further delayed images appears unnecessary for the purpose of diagnosing infection. In contrast in patients with an early mild LeukoScan uptake intensity only, delayed imaging appears to be recommendable for improving specificity.     

Comparison between Tc-HMPAO labelled white cells and Tc LeukoScan in the investigation of inflammatory bowel disease

OBJECTIVES: (99m)Tc-HMPAO labelled leukocyte imaging (white cell scan) is used in the investigation and assessment of patients with inflammatory bowel disease (IBD), while (99m)Tc LeukoScan has been used to demonstrate the presence of orthopaedic infections and appendicitis. The single-injection technique used for the administration of LeukoScan removes the need for handling blood and the complex separation and labelling techniques that are required for white cell imaging. This study set out to investigate whether LeukoScan could be used to image IBD. METHODS: Twenty-two patients under investigation for suspected IBD agreed to undergo LeukoScan imaging within 7 days of their routine planar white cell scan. Following injection of 650 MBq (99m)Tc LeukoScan planar images were acquired at 1, 2 and 4 h and single photon emission computed tomography (SPECT) images at 4 h post-injection. RESULTS: When both sets of images were compared to the clinical diagnosis, the sensitivity and specificity were 0.88 and 0.83 for white cell imaging and 0.88 and 0.50 for LeukoScan SPECT at 4 h. The figures for the specificity and sensitivity of the LeukoScan 2 h and 4 h planar images were 0.44 and 1.00, and 0.75 and 0.50, respectively. When the LeukoScan and white cell images were compared, the 4 h LeukoScan SPECT images showed additional areas of uptake in 10 patients. CONCLUSIONS: The study demonstrates that LeukoScan locates IBD. However, the sensitivity and specificity preclude its use for the routine detection of this disease. Comparisons with white cell scan images show that LeukoScan is taken up slowly in IBD and also appears in the normal bowel by 4 h.     

Comparison of SPECT/CT, SPECT, and planar imaging with single- and dual-phase (99m)Tc-sestamibi parathyroid scintigraphy.

Various methodologies for (99m)Tc-sestamibi parathyroid scintigraphy are in clinical use. There are few direct comparisons between the different methods and even less evidence supporting the superiority of one over another. Some reports suggest that SPECT is superior to planar imaging. The addition of CT to SPECT may further improve parathyroid adenoma localization. The purpose of our investigation was to compare hybrid SPECT/CT, SPECT, and planar imaging and to determine whether dual-phase imaging is advantageous for the 3 methodologies. METHODS: Scintigraphy was performed on 110 patients with primary hyperparathyroidism and no prior neck surgery. Of these, 98 had single adenomas and are the subject of this review. Planar imaging and SPECT/CT were performed at 15 min and 2 h after injection. Six image sets (early and delayed planar imaging, SPECT, and SPECT/CT) and combinations of the 2 image sets were reviewed for adenoma localization at 13 possible sites. Each review was scored for location and certainty of focus by 2 reviewer groups. Surgical location served as the standard. Sensitivity, specificity, area under the curve, positive predictive value, negative predictive value, and kappa-values were determined for each method. RESULTS: The overall kappa-coefficient (certainty of adenoma focus) between reading groups was 0.68 (95% confidence interval, 0.66-0.70). The highest values were for dual-phase studies that included SPECT/CT. Dual-phase planar imaging, SPECT, and SPECT/CT were statistically significantly superior to single-phase early or delayed imaging in sensitivity, area under the curve, and positive predictive value. Neither single-phase nor dual-phase SPECT was statistically superior to dual-phase planar imaging. Early-phase SPECT/CT in combination with any delayed imaging method was superior to dual-phase planar imaging or SPECT for sensitivity, area under the curve, and positive predictive value. CONCLUSION: Early SPECT/CT in combination with any delayed imaging method was statistically significantly superior to any single- or dual-phase planar or SPECT study for parathyroid adenoma localization. Localization with dual-phase acquisition was more accurate than with single-phase (99m)Tc-sestamibi scintigraphy for planar imaging, SPECT, and SPECT/CT.     

^99Tc^m—MIBISPECT结合定位CT显像诊断功能亢进异位甲状旁腺的价值

目的评价^99Tc^m-甲氧基异丁基异腈（MIBI）SPECT结合定位CT显像对功能亢进异位甲状旁腺的定位诊断价值。方法回顾性分析28例功能亢进异位甲状旁腺患者的手术、病理及影像资料。28例均行常规CT检查,其中25例先行双时相^99Tc^m-MIBI显像,对甲状腺外存在异常放射性浓聚灶患者,随即进行SPECT结合定位CT采集,经计算机处理得到二者融合图像,对放射性浓聚灶进行精确定位。以手术及病理检查结果为检查“金标准”,所有患者均按4个甲状旁腺计算,经手术及病理检查证实的为阳性,其余判为阴性。CT检查与核医学显像结果的比较采用四格表,检验。结果手术中28例患者共摘除28个异位病灶,均为单发。病理检查结果均为腺瘤。28例患者常规CT检查共发现22个阳性病灶,其中真阳性17个,假阳性5个,另假阴性11个,真阴性79个;25例^99Tc^m-MIBISPECT结合定位CT显像发现阳性病灶23个,无假阳性,另假阴性2个,真阴性75个。常规CT检查与核医学显像对检出病理性甲状旁腺的灵敏度分别为61％（17／28）、92％（23／25）,特异性为94％（79／84）、100％（75／75）,准确性为86％（96／112）、98％（98／100）,阳性预测值为77％（17／22）、100％（23／23）,阴性预测值为88％（79／90）、97％（75／77）;两者间比较差异有统计学意义,灵敏度：χ^2=6．98,P〈0．01,特异性：χ^2=4．61,P〈0．05,准确性：χ^2=10．30,P〈0．01,阳性预测值：χ^2=5．88,P〈0．05,阴性预测值：χ^2=5．36,P〈0．05。结论^99Tc^m—MIBI SPECT结合定位CT显像对功能亢进异位甲状旁腺的定位诊断优于常规CT,但存在一定的假阴性。     

99Tcm-PYP延迟及断层显像诊断转甲状腺素蛋白相关心脏淀粉样变的应用价值

目的:探讨⁹⁹Tc^m-焦膦酸盐(PYP)不同采集方法在心脏淀粉样变(CA)诊断与病理分型中的应用。方法:回顾性分析2018年12月至2019年12月间北京协和医院31例临床怀疑CA的患者资料,其中男22例、女9例,年龄21~81(57.2±13.4)岁。患者注射⁹⁹Tc^m-PYP后不同时间行平面显像[早期显像(注射后1 h)、延迟显像(注射后2~3 h)]和断层显像(注射后1 h)。以临床诊断为标准,分别采用视觉评分法(≥2分为阳性)和半定量法[心脏与对侧肺摄取比值(H/CL)≥1.5诊断为阳性]分析⁹⁹Tc^m-PYP不同采集方法获得的CA及非CA患者的影像学特点。采用单因素方差分析和Bonferroni检验分析数据。结果:根据临床诊断,CA组15例[转甲状腺素蛋白相关CA(ATTR-CA)5例、轻链型CA(AL-CA)10例],非CA组16例。5例ATTR-CA患者双时相显像和SPECT/CT显像均为阳性;10例AL-CA患者中3例早期显像阳性,延迟显像和SPECT/CT显像阴性;16例非CA患者双时相显像和SPECT/CT显像均为阴性。延迟期平面显像及断层显像灵敏度均为5/5,特异性均为10/10,阳性预测值均为5/5,阴性预测值均为10/10,准确性均为15/15。31例患者中,转甲状腺素蛋白相关(TTR)突变基因患者16例,其中4例为家族性突变型(ATTRv),表现为⁹⁹Tc^m-PYP显像阳性;12例诊断为非CA,表现为显像阴性。ATTR-CA组与AL-CA组早期显像H/CL(2.11±0.24与1.31±0.07)与延迟显像H/CL(2.02±0.19与1.30±0.05)差异均有统计学意义(F值:75.41和87.15,Bonferroni检验,均P<0.01)。结论:早期平面显像对CA分型存在误诊现象,延迟期平面显像及断层显像结果一致性好,可准确诊断ATTR-CA。⁹⁹Tc^m-PYP显像有助于发现TTR突变基因患者是否合并CA。     

201Tl SPECT in the detection of mediastinal lymph node metastases from lung cancer

201Tl SPECT was performed to detect mediastinal involvement in 80 patients with lung cancer who underwent surgery within a week after the SPECT study. Out of 29 patients with mediastinal involvement 16 (55%) were positive on the 201Tl early scan at 15 min postinjection and 22 (76%) were positive on the delayed scan at 3 h. These metastatic lymph nodes tended to be visualized much better on the delayed scan. In all patients with true positive results on the delayed scan, the mediastinal lymph nodes were plural, with a lesion of more than 14 mm in size. Seven false negative cases were found to have metastatic lesions less than 12 mm in size. Both the early and delayed scans showed false positive accumulation in six of 51 patients without mediastinal involvement (specificity 88%). Thus the overall accuracy for the delayed scan was 84%. The 201Tl delayed SPECT is thought to be a good noninvasive method for assessing mediastinal lymph node metastases from lung cancer.     

Prosthetic vascular graft infection imaging

PurposeWe are reporting our experience with imaging of vascular graft infections using computed tomography angiography (CTA), white blood cell (WBC) scintigraphy and software-based fusion imaging.Material and methodsInstitutional review board approval was obtained. We performed a retrospective review of patients who had clinical signs and symptoms of vascular graft infection in whom both WBC single photon emission computed tomography (SPECT) and CTA was performed between 2005 and 2010. We performed fusion imaging with available data using software coregistration technique and analyzed outcome of the patients.ResultsWe had 20 patients; 11 had grafts of the aorta, five had peripheral vascular grafts, three had aortic and peripheral vascular grafts, and one had a thoracic aortic graft. WBC imaging was positive in 10 patients, negative in six patients and indeterminate in 4 patients. CTA was positive in six patients, negative in four patients and indeterminate in 10 patients. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value (NPV) for WBC, CTA and WBC SPECT/CTA fusion were 75/100/80/100/50%, 88/50/80/88/50% and 94/50/85/88/67% respectively.ConclusionThe use of CTA, WBC scintigraphy, and image co-registration influenced the diagnostic confidence of graft infection and the outcome of the patients. Software-based fusion imaging of both modalities resulted in improved sensitivity, accuracy, and NPV.     

Preoperative 99mTc-sestamibi scintigraphy in patients with primary hyperparathyroidism and concomitant nodular goiter: comparison of SPECT-CT, SPECT, and planar imaging

BACKGROUND: Investigations using a hybrid single photon emission computed tomography/computed tomography (SPECT-CT) scanning technique have been carried out in limited studies and have shown mixed results. However, the assessment of this technique for the detection of parathyroid adenoma in patients with a nodular goiter was performed in only one study with a small sample size. The aim of this prospective study was to assess the role of Tc-sestamibi parathyroid SPECT-CT scans for localization of parathyroid adenomas with a concomitant nodular goiter using Tc-methoxyisobutyl isonitrile (MIBI) scintigraphy and to compare it with SPECT and planar imaging. METHODS: This study was conducted on 48 patients with primary hyperparathyroidism and nodular goiter, who were candidates for parathyroid surgery and had been referred for parathyroid scintigraphy. The patients underwent an early set of planar Tc-MIBI scanning procedures first, followed by SPECT and CT scannings, and finally a delayed set of planar Tc-MIBI scannings. Sensitivity, specificity, negative and positive predictive values, and accuracy were determined on a per-parathyroid-gland basis for each scanning method, as defined by histology and follow-up. RESULTS: The surgery was successful in 48 out of 50 patients with primary hyperparathyroidism concomitant with thyroid nodularity, and data were completed for 80 sites in 48 patients. The accuracy of SPECT-CT in correctly identifying a parathyroid adenoma was 85.00, versus 75.00% for SPECT (P=0.01, significant). The sensitivity and specificity for SPECT-CT were 77.55 and 96.77%, respectively, versus 67.34 and 87.09%, respectively, for SPECT (P=0.12 and 0.12, not significant). There were nine sites that showed better localization on SPECT-CT scans relative to SPECT images, of which five sites were located in the ectopic regions. CONCLUSION: The results of our study indicate that SPECT-CT is more accurate than sestamibi planar imaging and SPECT for the preoperative identification of parathyroid lesions in patients with primary hyperparathyroidism concomitant with thyroid nodularity. Also, we would recommend the use of SPECT-CT for a workup of all patients with ectopic glands who are scheduled for minimally invasive parathyroid surgery.     

Assessment of the diagnostic capacity of planar scintigraphy and SPECT with 99mTc-HMPAO-labelled leukocytes in superficial and deep sternal infections after median sternotomy

Sternal infection is a rare complication of median sternotomy but is associated with considerable morbidity and mortality, particularly in the case of deep sternal infection (mediastinitis). Successful treatment depends on early diagnosis and on the location (deep or superficial) of the infection. Radiological techniques have many limitations, and although 67Ga scintigraphy is effective, it delays diagnosis by 48 h. We assessed the diagnostic capacity of planar scintigraphy and single photon emission computed tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (HMPAO)-labelled leukocytes in deep sternal infections after median sternotomy. We prospectively studied 41 patients with clinical suspicion of deep sternal infection 4 and 20 h after administration of the tracer. The final diagnosis was deep sternal infection in nine patients and superficial sternal infection in 10, with infection being ruled out in 22 patients. Planar scintigraphy did not detect any of the deep sternal infections at either 4 h or 20 h. SPECT correctly identified eight of the nine deep sternal infections at 4 h and all seven at 20 h, with no false positive results. Planar scintigraphy identified 16 of the 18 superficial sternal infections at 4 h and all of them at 20 h. SPECT identified 17 of these 18 infections at 4 h and all of them at 20 h. Other infections unrelated to the sternotomy were identified in seven patients. Leukocytes labelled with 99mTc-HMPAO are a highly reliable method for the early diagnosis of sternal infections after median sternotomy. Use of SPECT allows determination of the depth of the infection and differentiation of superficial from deep sternal infections. It is also possible to detect other sites of infection, thus providing alternative diagnoses.     

Radiolabelled white blood cell scintigraphy in the work-up of dermal filler complications

Purpose

Scintigraphy with radiolabelled autologous white blood cells (WBC) is a widely used method for the detection of sites of infection. In this study we evaluated the role of WBC scintigraphy in the diagnosis and follow-up of patients with suspected soft tissue infection caused by dermal fillers in the face. We compared several qualitative and quantitative interpretation criteria and the results obtained with MRI and high-frequency US (HFUS).

Methods

Between 2007 and 2011, ten consecutive patients (all women) aged between 25 and 65 years showing a reaction to dermal fillers were enrolled in the study. In five of these patients WBC scintigraphy was repeated at the end of therapy. Scintigraphy with ^99mTc-HMPAO-labelled WBC was performed in each patient acquiring planar and SPECT images at 3 h and 20 h as well as HFUS with Doppler analysis and MRI with Gd-DTPA. The final diagnosis was determined by fine-needle aspiration and microbiological analysis of lesions in eight patients (before therapy in six and after therapy in two) and by clinical data and follow-up (at least 1 year) in seven patients (before therapy in four and after therapy in three). Two patients were treated with steroids, and the others were treated with antibiotics for 3 weeks. Several qualitative and semiquantitative interpretation criteria were applied to define the best strategy for accurate diagnosis of infections, implemented by SPECT images in patients with doubtful planar scans. The WBC scintigraphy results were also compared with the MRI and HFUS results.

Results

Sensitivity, specificity and accuracy were respectively 90 %, 100 % and 93.3 % for WBC scintigraphy with qualitative and semiquantitative interpretation of planar images and 100 %, 100 % and 100 % with qualitative analysis of SPECT images. Sensitivity, specificity and accuracy for HFUS were 44 %, 66 % and 50 %, and for MRI were 50 %, 100 % and 67.6 %, respectively. Scans performed after therapy in five patients were negative in three and still positive in two (all true results).

Conclusion

In conclusion, scintigraphy with radiolabelled WBC was found to be the most accurate method for diagnosing infection in patients with long-term dermal filler complications, particularly using qualitative analysis of SPECT images. No differences were observed with planar images using either qualitative or semiquantitative analysis. HFUS and MRI may provide additional important information for defining the nature of the filler and for surgery, but are not accurate enough for diagnosing infection.     

Increased sensitivity and confidence of SPECT over planar imaging in dual-phase sestamibi for parathyroid adenoma detection

PURPOSE OF REPORT: To determine the usefulness of SPECT imaging over planar imaging for the detection of parathyroid adenomas using dual-phase Tc-99m sestamibi. MATERIALS AND METHODS: The records of patients referred for dual-phase sestamibi scintigraphy for detection of parathyroid adenomas were reviewed retrospectively. The images were reviewed blindly and planar images were compared with SPECT. The imaging results were compared with the operative results to determine the sensitivity, accuracy of localization, and confidence of the reporting radiologist. RESULTS: The records of 37 patients were reviewed. Sensitivity was 62% for planar imaging and 73% for SPECT. There was one false positive. The side of the adenoma was correctly identified in all other patients. Confidence of detection was higher for SPECT than for planar imaging. CONCLUSION: SPECT imaging increased the sensitivity and confidence of the detection of parathyroid adenomas. The results indicate that SPECT should be used for all preoperative parathyroid localization.     

99Tcm—MIBI显像对腮腺区肿块的诊断价值

目的探讨99Tc^m_MIBI显像在腮腺肿块术前定性诊断中的价值。方法对32例单侧腮腺肿块患者术前行腮腺区99Te^m-MIBI显像,所有病例均行早期和延期显像以判断肿块性质。判断结果与病理诊断相比较。定性分析行Fisher确切概率法检验,组间病变侧与对侧放射性摄取比值（T／N）比较行t检验。结果99TcA^m．MIBI显像对腮腺区恶性肿瘤诊断的灵敏度、特异性和准确性分别为90．00％（9／10）、86．36％（19／22）和87．50％（28／32）。22例腮腺区良性肿块中显像阴性19例（86．36％）,假阳性3例（13．64％）;10例腮腺恶性肿块中显像阳性9例（90．00％）,假阴性1例（10．00％）;定性分析经Fisher确切概率法检验差异有统计学意义（P=0．00018）。腮腺区良恶性肿块T／N：早期相分别为1．45±0．38和1．65-t-O．63,两者差异有统计学意义（t=20．4,P〈0．01）;延期相分别为1．43±0．56和1．77-4-0．59,两者差异也有统计学意义（t=2．4,P〈0．05）。结论99Tc^m一MIBI显像可作为腮腺区肿块术前定性诊断的有效辅助手段。     

Leukoscan for orthopaedic imaging in clinical practice

Studies have suggested that orthopaedic infection can be successfully imaged with 99mTc antigranulocyte antibody Fab' fragments (Leukoscan). This study examined the value of the technique in a UK clinical practice. A retrospective review of the first 55 patients imaged was performed. Patients had three-phase bone scintigraphy followed by Leukoscan imaging. The latter was performed using planar views 2 h and 6 h post-injection of 750 MBq 99mTc Leukoscan. In 47 patients there was adequate clinical information available to compare to the scintigraphy result. There were 13 positive infections. The Leukoscan findings produced 11 true positives, 26 true negatives, eight false positives and two false negatives with resulting sensitivity 85%, specificity 77%, positive predictive accuracy 58%, and negative predictive accuracy 93%. This study suggests that Leukoscan can be used successfully to image orthopaedic infection, with its greatest strength being a high negative predictive accuracy. Positive studies may require further correlative imaging.     

Nuclear medicine imaging in tuberculosis using commercially available radiopharmaceuticals

In this paper, data available on nuclear medicine imaging using commercially available radiopharmaceuticals for the differentiation, staging, and prediction or assessment of the response to treatment in tuberculosis (TB) are reviewed. Limited available studies suggest that single photon emission computed tomography (SPECT) using either 201Tl, 99mTc-sestamibi, or 99mTc-tetrofosmin is accurate (≥85%) and has a high negative predictive value (≥90%) for the differentiation of TB from carcinoma in patients presenting with a solitary pulmonary nodule (SPN). The criteria for detection of TB on 201Tl SPECT are nondepiction of the suspicious lesion in the delayed image or a negative retention index [washout on the delayed images (3–4 h postinjection) vs. the early image (5–15 min postinjection)] and a comparable-to-background uptake on 99mTc-sestamibi or 99mTc-tetrofosmin SPECT. Another SPECT tracer of potential interest for the differentiation of TB from malignant SPN that warrants further exploration, is N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). In contrast, 18F-fluorodeoxyglucose (18F-FDG) PET is unable to differentiate malignancy from TB and thus cannot be used as a tool to reduce futile biopsy/thoracotomy in these patients. A limited number of studies have reported on the potential of nuclear medicine imaging in assessment of the extent of disease in patients with extrapulmonary TB using 67Ga-citrate SPECT and 18F-FDG PET, respectively. 67Ga-citrate SPECT was shown to be as sensitive as bone scintigraphy for the detection of bone infection and was found to be complementary to computed tomography (CT) imaging. 18F-FDG PET was found to be significantly more efficient when compared with CT, respectively, in over half of patients for the identification of sites of lymph node involvement that were missed by CT and often the only sites of extrapulmonary TB identified. Unfortunately, 18F-FDG PET findings did not lead to alterations in treatment planning in any of the patients under study. Additional studies confirming these findings are urgently required. Similar to the setting of SPN, 18F-FDG PET cannot differentiate malignant lymph node involvement from lymph node involvement by TB. These results and the recent findings of Demura and colleagues using 18F-FDG PET further suggest that nuclear medicine imaging techniques could be used for the evaluation of therapeutic response. Prospective studies, focusing on specific subgroups of patients in whom such an imaging approach might be clinically relevant, for example in multidrug-resistant TB patients, are warranted. In acquired immunodeficiency syndrome patients, 67Ga scintigraphy proved to be a reliable and sensitive method for the primary detection and follow-up of opportunistic pneumonias, including TB. Combining 201Tl scintigraphy with 67Ga scintigraphy was shown to increase the specificity for both pulmonary and extrapulmonary TB, which is a 67Ga(+) and 201Tl(-) mismatch pattern in acquired immunodeficiency syndrome patients that is specific for mycobacterial infections. Finally, the results obtained using both SPECT and PET indicate that nuclear medicine could be an important noninvasive method for the determination of disease activity, detection of extrapulmonary TB, and determination of response to therapy.     

Imaging of low-grade bone infection with a technetium-99m labelled monoclonal anti-NCA-90 Fab' fragment in patients with previous joint surgery

Low-grade bone infection represents a serious clinical problem. Diagnostic options are often insufficient, yet the therapeutic implications of proven disease are important, especially in patients with prosthetic joint replacement. Technetium-99m labelled monoclonal anti-NCA-90 granulocyte antibody Fab' fragment (MN3 Fab') has been shown to be useful in bone and joint infection, but there are no data specifically referring to low-grade bone infection. We therefore analysed 38 scans in 30 consecutive patients (age range, 30-85 years; median age, 62 years) referred for suspected low-grade bone infection. There were 17 patients (21 scans) with total hip arthroplasty (THA), six with total knee arthroplasty (TKA), three who had undergone hip or knee surgery for trauma and five (seven scans) with resected hips and no endoprostheses (Girdlestone situations); one of these five patients had been investigated before with THA in situ and another prior to surgery for low-grade coxitis. There were no patients with rheumatoid arthritis as the underlying disease. Results were verified by means of bacteriological cultures, histopathological findings and/or follow-up and compared with the respective Zimmerli scores, which were used for clinical assessment of inflammatory activity. In one patient, the final diagnosis could not be established. One, 5 and 24 h after intravenous injection of up to 1.1 GBq of MN3 Fab', whole-body and planar scans were performed using a dual-head gamma camera. Scans were analysed visually and semiquantitatively adopting an arbitrary score ranging from 0 to 3. There were 13 true positive, 14 true negative and 10 false positive outcomes, yielding an overall sensitivity of 100%, an overall specificity of 58%, an accuracy of 73% and positive and negative predictive values of 57% and 100%, respectively. In patients with THA or TKA, accuracy was 81% and 80%, respectively, while it dropped to 43% in patients with Girdlestone situations owing to a high proportion of false positive findings (4/7) in this subgroup. Scintigraphic score was 1 in all of the false positive and in 11/13 true positive findings. The two remaining true positive findings displayed scintigraphic scores of 2 and 3, respectively. Scintigraphic and Zimmerli scores were loosely correlated (Spearman rho=0.38, P<0.05). Infection was excluded in 22/24 investigations with Zimmerli scores of <6. In this group, there were 13 scintigraphically true negative, nine false positive outcomes, and just two true positive outcomes. In 11/12 investigations with Zimmerli scores of 6 or 7, infection was verified and scintigraphic outcome was accordingly true positive, while the remaining patient was true negative. In conclusion, MN3 Fab' scintigraphy proved to be highly sensitive but not specific in diagnosing low-grade infections of the hip and knee regions in patients with previous joint surgery. The method seems reliable in excluding but not in proving the presence of infection. MN3 Fab' scintigraphy should not be applied in patients with Girdlestone situations. Assessment of infection using the Zimmerli score was more reliable than MN3 Fab' scintigraphy in this group of patients without rheumatoid arthritis as the underlying disease. Considering results from the literature concerning leucocyte scintigraphy, MN3 Fab' scintigraphy may be clinically useful in evaluating low-grade bone infection in THA and TKA patients with Zimmerli scores above 5 and concomitant rheumatoid arthritis or other inflammatory diseases.     

CT and MR imaging findings in athletes with early tibial stress injuries: comparison with bone scintigraphy findings and emphasis on cortical abnormalities

PURPOSE: To prospectively compare computed tomography (CT), magnetic resonance (MR) imaging, and bone scintigraphy in athletes with clinically suspected early stress injury of tibia. MATERIALS AND METHODS: Medical ethics committee approval and informed consent were obtained. A total of 42 patients experiencing tibial pain due to early stress injuries were evaluated. Eight patients had bilateral involvement; thus, 50 tibiae were evaluated. All patients underwent initial radiography that was negative for injury. MR imaging, CT, and bone scintigraphy were performed in all patients within 1 month of onset of symptoms. Ten asymptomatic volunteers served as the control group. Location of stress injuries, types of bone alterations, and presence of periosteal and bone marrow edema were evaluated. Sensitivity, specificity, accuracy, and positive and negative predictive values of MR imaging and CT were assessed, as was sensitivity of bone scintigraphy. McNemar test was used to detect statistically significant differences. RESULTS: Sensitivity of MR imaging, CT, and bone scintigraphy was 88%, 42%, and 74%, respectively. Specificity, accuracy, and positive and negative predictive values were 100%, 90%, 100%, and 62%, respectively, for MR imaging and 100%, 52%, 100%, and 26%, respectively, for CT. Significant difference in detection of early tibial stress injuries was found between MR imaging and both CT and bone scintigraphy (McNemar test; P < .001 and P = .008, respectively). CONCLUSION: MR imaging is the single best technique in assessment of patients with suspected tibial stress injuries; in some patients with negative MR imaging findings, CT can depict osteopenia, which is the earliest finding of fatigue cortical bone injury.     

SPECT/CT双时相联合减影技术诊断甲状旁腺功能亢进症的增益价值

目的探讨在99Tcm-MIBI双时相平面显像的基础上联合减影平面显像及SPECT/CT融合显像对甲状旁腺功能亢进症（以下简称甲旁亢）患者术前诊断的增益价值。方法2015年3月至2016年3月序贯纳入本院甲旁亢患者28例。所有患者行放射性核素显像前1~2周检测血清甲状腺旁腺激素（PTH）及血钙值。静脉注射99TcmO₄-40~60 MBq后行甲状腺99TcmO₄-显像;待采集结束后,再次静脉注射99Tcm-MIBI 600 MBq,行早期99Tcm-MIBI平面显像,后行SPECT/CT融合显像。在行99Tcm-MIBI延迟平面显像后,获得减影平面显像。以病理诊断结果为金标准,计算各显像技术的诊断效能。显像技术检出病灶数据的比较采用配对卡方检验,其他数值型变量采用Wilcoxon秩和检验。结果原发性和继发性甲旁亢患者术前检测PTH水平分别为（102.4±88.8）、（98.2±53.6）pmol/L,血钙水平分别为（2.9±0.3）、（1.9±0.2）mmol/L。28例甲旁亢患者共发现可疑性结节55处,其中40处甲旁亢病灶,15处非甲旁亢病灶。双时相检出19处病灶和2处阳性浓聚灶,其灵敏度为47.5%（19/40）。在双时相诊断甲旁亢病灶为阴性结果的患者中,减影相检出其他5处病灶,提高了病灶检出的灵敏度（60.0%）,差异有统计学意义（χ2=2.716,P=0.125）。SPECT/CT融合显像检出甲旁亢病灶26处,将双时相和减影相联合分析,检出甲旁亢病灶25处、非甲旁亢病灶4处;将双时相联合SPECT/CT融合显像分析,检出甲旁亢病灶26处、非甲旁亢病灶1处。减影相联合SPECT/CT融合显像与全部联合显像诊断效能相同,检出甲旁亢病灶27处、非甲旁亢病灶1处,其灵敏度和特异度较双时相（67.5% vs.47.5%和93.3% vs.86.7%）提高,差异均有统计学意义（χ2=6.635,P=0.02;χ2=4.432,P=0.04）。结论甲旁亢患者在行常规双时相平面显像的基础上联合减影平面显像及SPECT/CT融合显像,较单纯行双时相平面显像可以提高患者病灶的检出率。     

The evaluation of sacroiliitis using 99mTc-nanocolloid and 99mTc-MDP scintigraphy.

The role of imaging studies in the evaluation of patients with sacroiliitis is controversial. We aimed to evaluate the role of nanocolloid and bone scintigraphy in patients with sacroiliitis and to investigate the clinical relevance of imaging findings. Thirty-two patients with clinically sacroiliac disease (nine females, 23 males, aged 22-47 years) underwent scintigraphic and radiographic examinations and all imaging studies were performed within 2 weeks. Twenty-five subjects were also included as a control group (10 females, 15 males, aged 20-51 years) for quantitative analysis of the bone scan. The quantitative analysis was done by using regions of interest drawn over the right and left sacroiliac (SI) joint and sacrum (S) and SI/S ratios were calculated. Abnormal uptake was defined as an uptake higher than the mean +/- 2 SD of the control SI/S values. Bone scintigraphy was performed using a three-phase technique and single photon emission computed tomography (SPECT). Nanocolloid scintigraphy (NS) was performed 1 h later, after administration of 370 MBq 99mTc-nanocolloid, and evaluated visually. Each of the scintigraphic examinations was performed on separate days within the same week. Sensitivity values were 25%, 47%, 69% and 97%, and specificity values were 80%, 90%, 95% and 90% in quantitative bone scanning (QBS), 99mTc-NS, planar and SPECT bone imaging, respectively, when the clinical findings were considered as the 'gold standard'. Our results showed that bone SPECT scanning was more sensitive than planar imaging, but planar imaging was the most specific method. SPECT was also the most associated technique with clinical findings. 99mTc-NS was neither specific nor sensitive enough in the detection of sacroiliitis although it could be helpful for the confirmation of inflammation.     

Diagnostic efficacy of technetium-99m pentavalent-dimercapto succinic acid versus gallium-67 citrate, imaging in patients with highly suspected acute bone and joint infections

The purpose of this study was to evaluate and compare the diagnostic efficacy of (99m)Tc(V) dimercaptosuccinic acid ((99m)Tc(V)DMSA) with the (67)Ga-citrare ((67)Ga-C) scintigraphy in patients with suspected bone and joint infection. Thirty one patients, 19 men and 12 women, aged 18-78 y with median age 56 y, with suspected acute bone infection, were enrolled in this study. Besides (67)Ga-C and (99m)Tc(V)DMSA scintigraphy, all patients underwent X-ray radiography and technetium-99m methylene disphosphonate ((99m)Tc-MDP) bone scan for supporting the initial diagnosis. The (99m)Tc-MDP bone scan was considered positive for acute bone and joint infection when all its four scintigraphic phases were positive. Final diagnosis was based on needle aspiration and/or biopsy findings. Sensitivity, specificity, accuracy, positive and negative predictive values (PPV and NPV) were calculated. Our results have shown the following: Seventeen patients (17/31) had histologically confirmed acute bone and joint infections, while the remaining patients had no infection. (99m)Tc(V)DMSA diagnosed bone and joint infections in all positive (17/31) patients while (67)Ga-C in 16/31 patients. Discordant scintigraphic results were observed by (67)Ga-C in 2/31 cases: in one positive case of femur postoperative infection (false negative for (67)Ga-C) and in one case of clinicaly suspected infection in the femur while the patient had a preexisting fracture (false positive with (67)Ga-C). No false negative results were observed with (99m)Tc(V)DMSA. Sensitivity, specificity, PPV, NPV and accuracy were maximum for (99m)Tc(V)DMSA, while for (67)Ga-C were: 94.1%, 93%, 94.1%, 93%, and 93.5% respectively. It is concluded that considering the high sensitivity and specificity of (99m)Tc(V)DMSA in the detection of acute bone and joint infections, the lower radiation dose, the cost and the shorter time spent for the imaging procedure, as compared to (67)Ga-C, (99m)Tc(V)DMSA should be preferred to (67)Ga-C as a bone scan agent for the detection of acute bone and joint infections.