Clinical significance of abdominal scintigraphy using 99mTc-HMPAO-labelled leucocytes in patients with seronegative spondyloarthropathies

Abdominal scintigraphy shows silent gut inflammation in patients with spondyloarthropathies (Sp) without clinical evidence of gut inflammation. Abdominal scintigraphy images are different than those obtained in patients with ulcerative colitis or Crohn's disease and are not related to the anti-inflammatory drugs administered. The aim of this study was to examine the clinical associations of findings on abdominal scintigraphy in patients with Sp. A total of 204 Sp patients (European Spondylarthropathy Study Group 1991 criteria) and 54 non-Sp controls receiving non-steroidal anti-inflammatory drugs were studied. Abdominal scintigraphy images were obtained at 30 and 120 min after injection of technetium-99m hexamethylpropylene amine oxime (^99mTc-HMPAO)-labelled leucocytes. ^99mTc-HMPAO-labelled leucocyte scans were positive in 104 Sp patients (50.9%) and in six non-Sp controls (2.9%) (P<0.001; OR=8.32; 95% CI=3.23-22.67). Silent gut inflammation was not associated with any of the following: age of onset, duration of evolution, sex, family history of Sp or psoriasis, articular manifestations, extra-articular manifestations, radiological findings or HLA-B27 positivity. Positive abdominal scintigraphy was associated with active disease (P<0.0001; OR=52.7; 95% CI=19-145.6) and an increase in the C-reactive protein (P<0.005; OR=3.4; 95% CI=1.5-7.4). It is concluded that (a) abdominal scintigraphy using ^99mTc-HMPAO-labelled leucocytes is of value in detecting the silent gut inflammation in Sp patients, and (b) silent gut inflammation is related to the clinical activity, but is not associated with any particular type of illness or with HLA-B27.     

Abdominal scintigraphy using99mTc-HMPAO-labelled leucocytes in patients with seronegative spondylarthropathies without clinical evidence of inflammatory bowel disease

Abdominal scintigraphy with technetium-99m hexamethylpropylene amine oxime (^99mTc-HMPAO)-labelled leucocytes is an excellent tool for evaluating disease extent and activity of intestinal lesions in patients with inflammatory bowel disease (IBD). In some cases of seronegative spondylarthropathies (SSp), IBD may remain subclinical. The aim of this study was to evaluate the presence of positive abdominal scintigraphy in patients with SSp and without clinical symptoms or signs of IBD. To this end we studied 32 patients with active SSp (European Spondylarthropathy Study Group 1991 criteria) without clinical evidence of IBD (eight had ankylosing spondylitis, four psoriatic arthritis, three reactive arthritis an 17 undifferentiated SSp) and 11 controls without SSp. All SSp and control patients received similar doses of non-steroidal anti-inflammatory drugs (NSAIDs). Abdominal scintigraphic images were obtained at 30 and 120 min after re-injection of^99mTc-HMPAO-labelled leucocytes. The^99mTc-HMPAO-labelled leucocyte scan was positive in 17 patients with SSp (53.1%) (six with ankylosing spondylitis, three with psoriatic arthritis, two with reactive arthritis and six with undifferentiated SSp). Fourteen patients scored from 2 to 4 on the intensity of uptake scale. The colon and terminal ileum were predominantly involved. Axial involvement was more frequent in patients with a positive scan than in patients with negative results (P<0.05) (64.7% vs 26.6%; odds ratio: 5). No control patient showed a positive scan. It is concluded that^99mTc-HMPAO-labelled leucocyte scan shows increased uptake among patients with SSp without evidence of IBD. These findings provide new evidence linking SSp with intestinal inflammation and suggest that in some cases a bowel-related process could contribute to the development of SSp. Longterm follow-up studies with more patients are necessary to evaluate the diagnostic and therapeutic implications of these results.     

No gender bias in referral for coronary angiography after myocardial perfusion scintigraphy with technetium-99m tetrofosmin

BACKGROUND: Several studies have shown that the application of diagnostic and invasive procedures varies between men and women. The purpose of this study was to assess if referral for coronary angiography after technetium-99m tetrofosmin myocardial perfusion scintigraphy in 616 patients with undiagnosed chest pain might demonstrate gender bias. METHODS AND RESULTS: The primary end point for this study was coronary angiography within 90 days of myocardial perfusion scintigraphy. Women had more normal perfusion images than men (207 [70.9%] vs 160 [50.5%], P < .05). Of 242 patients with abnormal images (157 men, 85 women), 28 men (17.7%) and 17 women (20.0%) were referred for further invasive testing (P = not significant). Referral for coronary angiography increased relative to the number of defects. Univariate analysis showed that reversible and persistent defects were the most predictive variables for referral to coronary angiography (odds ratio [OR] 5.45, 95% confidence interval [CI] 3.10-9.58, P < .001, and OR 2.67, 95% CI 1.52-4.67, P = .001, respectively). More importantly, multivariate analysis showed that reversible perfusion defects (OR 4.77, 95% CI 2.48-9.17, P < .001) and persistent perfusion defects (OR 2.14, 95% CI 1.11-4.14, P = .02) were predictive of subsequent coronary angiography. No significant association between gender and subsequent coronary angiography was found both in univariate and multivariate logistic regression analysis (OR 0.64, 95% CI 0.37-1.12, P = .12, and OR 0.70, 95% CI 0.36-1.36, P = .28, respectively). CONCLUSIONS: Our study reveals that after correction for the presence and the severity of myocardial perfusion abnormalities, men and women were referred to coronary angiography at a similar rate. Thus, based on the results of technetium-99m tetrofosmin myocardial perfusion imaging, no substantial evidence for a gender-related bias could be found in the referral for further invasive testing.     

Diagnostic accuracy of bone scintigraphy in the assessment of cardiac transthyretin-related amyloidosis: a bivariate meta-analysis

Purpose

Cardiac transthyretin-related amyloidosis (ATTR) is a progressive and fatal cardiomyopathy. The diagnosis of this disease is frequently delayed or missed due to the limited specificity of echocardiography. An increasing amount of data in the literature demonstrate the ability of bone scintigraphy with bone-seeking radiopharmaceuticals to detect myocardial amyloid deposits, in particular in patients with ATTR. Therefore we performed a systematic review and bivariate meta-analysis of the diagnostic accuracy of bone scintigraphy in patients with suspected cardiac ATTR.

Methods

A comprehensive computer literature search of studies published up to 30 November 2017 on the role of bone scintigraphy in patients with ATTR was performed using the following search algorithm: (a) “amyloid” OR “amyloidosis” AND (b) “TTR” OR “ATTR” OR “transthyretin” AND (c) “scintigraphy” OR “scan” OR “SPECT” OR “SPET” OR “bone” OR “skeletal” OR “skeleton” OR “PYP” OR “DPD” OR “HMDP” OR “MDP” OR “HDP”. Pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR?) and diagnostic odds ratio (DOR) of bone scintigraphy were calculated.

Results

The meta-analysis of six selected studies on bone scintigraphy in cardiac ATTR including 529 patients provided the following results: sensitivity 92.2% (95% CI 89–95%), specificity 95.4% (95% CI 77–99%), LR+ 7.02 (95% CI 3.42–14.4), LR? 0.09 (95% CI 0.06–0.14), and DOR 81.6 (95% CI 44–153). Mild heterogeneity was found among the selected studies.

Conclusion

Our evidence-based data demonstrate that bone scintigraphy using technetium-labelled radiotracers provides very high diagnostic accuracy in the non-invasive assessment of cardiac ATTR.

     

Scintigraphic diagnosis of gastrointestinal bleeding with 99mTc-labeled blood-pool agents

Abdominal scintigraphy with 99mTc-labeled albumin or red blood cells was used in 68 patients to localize gastrointestinal bleeding or confirm that it had stopped. Acute, active bleeding was identified in 33 patients; characteristic patterns of bleeding from the stomach, biliary passages, small intestine, and colon are shown. Sensitivity was 0.86 (95% confidence limits, 0.57-0.98) and specificity was 1.0 (95% confidence limits, 0.82-1.0) in 33 patients who had scintigraphy and endoscopy performed in succession. Abdominal scintigraphy appears to be a valuable supplement to conventional diagnostic methods. In upper gastrointestinal bleeding, scintigraphy should be considered when endoscopy fails. In lower intestinal bleeding, scintigraphy should be the method of choice.     

99mTc-interleukin-2 and 99mTc-HMPAO granulocyte scintigraphy in patients with inactive Crohn's disease

Crohn's disease (CD) is a chronic inflammatory bowel disease that may involve the whole gut. Marked intestinal T cell and macrophage activation is a key feature of the disease. Polymorphonuclear cell infiltration is also observed in the diseased gut, mainly during active inflammation. Scintigraphic detection of granulocytes and activated lymphocytes infiltrating the gut wall may be useful in identifying a subgroup of patients with clinically inactive CD who are undergoing early clinical relapse. The aims of the present study were (a) to compare the effectiveness of scintigraphy with (99m)Tc-labelled interleukin-2 ((99m)Tc-IL2) and with (99m)Tc-HMPAO labelled granulocytes ((99m)Tc-WBC) in detecting the presence and extent of bowel inflammation in patients with long-term inactive CD (>12 months) and (b) to assess the accuracy of these techniques in predicting future disease relapse. We studied 29 patients with ileal and/or colonic CD in stable clinical remission (Crohn's Disease Activity Index <150 for at least 12 months) using both (99m)Tc-IL2 and (99m)Tc-WBC scintigraphy in order to evaluate the extent of acute and chronic inflammation in the bowel. Planar and single-photon emission tomography images were acquired in each patient at 1 h p.i. For quantitative analysis of (99m)Tc-IL2 uptake, the abdomen was divided into 32 regions of interest. Despite the absence of symptoms, 18 patients (62%) showed a positive (99m)Tc-IL2 and 18 (62%) a positive (99m)Tc-WBC scan. Only 12 patients (41.4% of the total group) were positive on both scans, and the sites of IL2 and granulocyte bowel uptake were usually located in different segments, indicating that in CD, acute and chronic inflammation can be present in different sites. As far as the prognostic role of the two scans in predicting future disease relapse is concerned, both (99m)Tc-IL2 and (99m)Tc-WBC scintigraphy showed a high negative predictive value (1.00 and 0.91, respectively) but a weak positive predictive value (0.44 and 0.39, respectively). Nevertheless, Kaplan-Meier curves generated between scintigraphic findings and time free from disease relapse were statistically different only for (99m)Tc-IL2 scintigraphy (log-rank test, P=0.013). These results indicate that (99m)Tc-IL2 scintigraphy can be useful in selecting CD patients in clinical remission who could benefit from preventive therapy to avoid disease relapse.     

Use of 99mTc (V) DMSA scintigraphy in the detection and localization of intestinal inflammation: comparison of findings and colonoscopy and biopsy

PURPOSE: To evaluate the potential use of technetium 99m (99mTc) (V) dimercaptosuccinic acid (DMSA) scintigraphy in the detection and localization of intestinal inflammation. MATERIALS AND METHODS: In a prospective study, 62 patients who were suspected of having intestinal inflammation and 30 control subjects were enrolled. All patients underwent 99mTc (V) DMSA scintigraphy and colonoscopy with biopsy within 1 week. 99mTc (V) DMSA scintigrams were interpreted blindly with respect to clinical information, and radiotracer uptake in the bowel segments was graded. The findings were then compared with the results of the colonoscopy and colonoscopic biopsy. RESULTS: In the detection of intestinal inflammation, findings at 99mTc (V) DMSA scintigraphy were as follows: true-positive in 55, false-positive in two, true-negative in 32, and false-negative in three. Overall sensitivity was 95%; overall specificity, 94%; and overall accuracy, 95%. CONCLUSION: Our results show that 99mTc (V) DMSA scintigraphy is a useful noninvasive diagnostic test for the detection and localization of intestinal inflammation.     

MRI versus scintigraphy with 99mTc-HMPAO-labelled granulocytes in the diagnosis of bone infection

PURPOSE: To assess the reliability of MRI and scintigraphy with 99mTc-HMPAO-labelled granulocytes in the diagnosis of bone infection. MATERIALS AND METHODS: Between November 2001 and November 2003, 25 patients (16 men and 9 women; age range 22-72 years; mean age 48 years) with suspected bone infection were evaluated. The lower limbs were more frequently involved (20/25 cases). MRI (T1 and T2-w sequences, both with and without fat suppression; T1-w fat-suppressed sequence after Gadolinium administration) and scintigraphy with 99mTc-HMPAO-labelled granulocytes were performed in all patients; the study was performed 30 min, 150 min and 24 h after the injection of 99mTc labelled autologous granulocytes. The maximum interval between MRI and scintigraphy was 15 days. The diagnosis was confirmed surgically (18/25 cases) or by clinical follow-up (7/25 cases). RESULTS: In 10/25 cases the clinical suspicion of bone infection was confirmed by MRI, scintigraphy and surgery. In 12/25 cases the clinical suspicion of bone infection was not confirmed either by imaging, surgery (5/12 cases) or follow-up (7/12 cases). In 3/25 cases the results were discordant: in 1/3 cases with chronic osteomyelitis confirmed by MRI and surgery, a false-negative diagnosis was made by scintigraphy. In 2/3 cases with negative MRI diagnoses confirmed by surgery, a false-positive diagnosis was made by scintigraphy owing to the infection of adjacent soft tissues. CONCLUSIONS: MRI is more reliable for the detection and evaluation of the local spread of bone infection. Conversely, when metallic devices causing artefacts on MR images are present, scintigraphy is the preferred alternative modality.     

99mTc-HMPAO labelled leucocyte scintigraphy in the diagnosis of pelvic inflammatory disease

BACKGROUND: Scintigraphy using leucocytes labelled with 99mTc hexamethylpropyleneamine oxime (99mTc-HMPAO) is widely used for the localization of inflammatory foci and abscesses in cases of acute pelvic inflammatory disease, which is one of the serious health problems of women of child-bearing age. Early diagnosis and effective management of this condition can preserve fertility and prevent serious complications, such as peritonitis and sepsis. AIM: To evaluate the importance of scintigraphy using 99mTc-HMPAO labelled leucocytes in the early diagnosis of patients with pelvic inflammatory disease. METHODS: Fifteen women (mean age 29.2+/-8 years, range 25-46 years) with suspicion of pyogenic pelvic inflammatory disease based on gynaecological examinations, clinical findings and blood tests were included in this study. The patients received 555 MBq 99mTc-HMPAO labelled leucocytes, by injection, and were scanned by scintigraphy 0.5-1, 3 and 24 h later in the anterior abdominal projection. Ten of the patients were then evaluated by abdominal or transvaginal ultrasonography, four by computed tomography and two by both ultrasound and computed tomography. The final diagnosis was made by surgical intervention. RESULTS: Scintigraphy detected pelvic inflammatory disease in five of the patients. In three of them the disease was apparent on the scans taken at 0.5-1 h, and in the other two it was apparent at 3 h. There were no false negative results, and one false positive result. The scan accurately reflected the absence of pelvic inflammatory disease in nine patients showing non-pathological tracer uptake in the lower abdominal region. CONCLUSION: We showed that scintigraphy with 99mTc-HMPAO labelled leucocytes had a sensitivity of 100%, specificity of 90%, overall accuracy of 93%, positive predictive value of 83%, and negative predictive value of 100%. Therefore, we conclude that 99mTc-HMPAO labelled leucocyte scans provide a rapid and highly accurate method for diagnosing pelvic inflammatory disease in women of child-bearing age. This adds an important contribution to the diagnosis of infection and helps determine further operative or conservative treatment.     

Technetium-99m-HMPAO-labeled leukocyte imaging in patients with seronegative spondyloarthropathies.

OBJECTIVE: Gut inflammation is frequent among patients with seronegative spondyloarthropathies (SSp). The purpose of this study was to evaluate the presence of positive abdominal findings in patients with SSp who did not have clinical symptoms or signs of inflammatory bowel disease (IBD). This represents a new indication for abdominal 99mTc-HMPAO-labeled leukocyte scintigraphy. METHODS: Eighty-six patients (59 with SSp and 27 controls) were prospectively imaged with 99mTc-HMPAO-labeled leukocytes. RESULTS: Leukocyte imaging was positive in 33 patients with SSp (56%), 27 of these patients scored between 2+ and 4+ (51%). Four (15%) control patients also had positive findings. CONCLUSION: These findings provide evidence linking SSp with intestinal inflammation. SSp may be an important new indication for 99mTc-HMPAO-labeled autologous leukocyte scintigraphy.     

Comparison between MR imaging and 99mTc MIBI scintigraphy in the evaluation of recurrent of persistent hyperparathyroidism

PURPOSE: To compare the sensitivity and positive predictive value of magnetic resonance (MR) imaging and technetium 99m 2-methoxyisobutyl-isonitrile (MIBI) scintigraphy for the detection of hyperfunctioning parathyroid tissue when used alone and in combination in a large patient population with recurrent or persistent hyperparathyroidism (HPT). MATERIALS AND METHODS: In 98 consecutive patients with biochemically proved recurrent or persistent HPT after surgery, MR imaging and 99mTc MIBI study findings were retrospectively reviewed and compared with surgical and histopathologic findings. The sensitivity and positive predictive value of MR imaging and 99mTc MIBI scintigraphy were compared with each other and in combination. RESULTS: In these patients, 130 abnormal parathyroid glands were identified at surgery. The sensitivity and positive predictive value of MR imaging were 82% (95% CI: 75%, 89%) and 89%, respectively; those for (99m)Tc MIBI scintigraphy were 85% (95% CI: 79%, 91%) and 89%. No significant difference was found between MR imaging and 99mTc MIBI scintigraphy for sensitivity (P =.7). The sensitivity and positive predictive value for the detection of abnormal parathyroid tissue on a per-gland basis increased to 94% (95% CI: 90%, 98%) and 98%, respectively, when only one of the two tests was required to be positive. CONCLUSION: MR imaging and 99mTc MIBI scintigraphy have similarly good sensitivity and positive predictive value for the detection of hyperfunctioning parathyroid tissue in patients after surgery. The combination of the two tests provided a substantial increase in sensitivity and positive predictive value.     

Usefulness of 18F-FDG PET-directed skeletal biopsy for metastatic neoplasm

RATIONALE AND OBJECTIVES: Technium-99m methylene diphosphonate (99mTc-MDP) bone scintigraphy and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) are useful imaging modalities to detect skeletal metastases. Several other conditions such as infection, fractures, and arthritis can cause false-positive results with either modality. However, PET is felt to be more specific than bone scintigraphy for malignancy. Our objective was to investigate the value of PET scan compared with bone scintigraphy for directing biopsies in patients with suspected metastatic bone lesions. MATERIALS AND METHODS: Retrospective case series of subjects with undergoing skeletal biopsy of suspected metastases detected by 99mTc-MDP scintigraphy or 18F-FDG PET scan. Reference standards were pathologic reports and follow-up for 6 months. The diagnostic test performance measures of true positive (TP), false positive (FP), and positive predictive value (PPV) were calculated for each group. The PPV with 95% confidence intervals (CI) was compared using the Fisher exact test. RESULTS: There were a total of 68 subjects. PET-directed skeletal biopsies (n = 39) showed 35 TP, 4 FP, and an 89.7% PPV (95% CI: 75.7-97.1%). Bone scintigraphy directed biopsies (n = 29) had 21 TP, 8 FP, and 72.4 % PPV (95% CI: 52.7-82.7%). The PPV was not significantly different between the groups (P = .10). CONCLUSION: This study supports that PET can be used to effectively direct bone biopsies to confirm metastatic neoplasm and suggests that PET may provide incremental improvement to diagnostic yield over bone scintigraphy. The role of PET compared with bone scintigraphy for directing skeletal biopsies warrants further verification.     

Imaging diagnosis of protein-losing enteropathy by 99mTc-labeled serum albumin

Abdominal scintigraphy with intravenous injection of 99mTc-labeled serum albumin was performed in 6 patients with protein-losing enteropathy (PLE) and 3 patients with non-gastrointestinal tract disorders. In 3 out of 6 patients with PLE, abnormal radioactivity was observed in the ileum region 3 hours after injection, and thereafter clear colon image was obtained. In the remaining 3 patients, the colon was visualized 24 hours after injection. On the other hand, in all patients with non-gastrointestinal tract disorders, no abnormal radioactivity was observed in the abdomen until 24 hours after injection. These results indicate that gastrointestinal protein loss could be demonstrated by scintigraphy with intravenously administered 99mTc-labeled serum albumin. In one healthy subject, 99mTc-labeled serum albumin was administered orally and abdominal scintigraphy was performed. Gastrointestinal tract image was only observed and no other image was demonstrated until 24 hours after oral administration. This result suggests that 99mTc excreted into the gastrointestinal tract is not reabsorbed. Therefore, abdominal scintigraphy with 99mTc-labeled serum albumin appears to be a simple and useful method for diagnosis of PLE.     

Correlation of CT Angiography and 99mTechnetium-Labeled Red Blood Cell Scintigraphy to Catheter Angiography for Lower Gastrointestinal Bleeding: A Single-Institution Experience

PurposeTo investigate the correlation of computed tomography (CT) angiography and ^99mTechnetium-labeled red blood cell (RBC) scintigraphy to catheter angiography (CA) in the management of lower gastrointestinal bleeding (LGIB) while considering potential nephrotoxic effects of iodinated contrast.Materials and MethodsFrom November 2012 to August 2017, 223 CAs performed for LGIB, including massive, ongoing, and obscure bleeding, were retrospectively identified in patients with pre-procedural CT angiography or RBC scintigraphy. Positive correlations and sensitivities were calculated for CT angiography and RBC scintigraphy using CA results as reference. Correlations were then compared while considering certain clinical presentations of LGIB. Contrast dose was compared with maximum creatinine recorded 48–72 hours after.ResultsThirty-eight patients underwent CT angiography; 173 patients underwent RBC scintigraphy; and 12 patients completed both studies. CT angiography had a positive correlation of 67.7% (95% confidence interval [CI]: 57.0, 76.7) and sensitivity of 85.2% (95% CI: 66.3, 95.8), whereas RBC scintigraphy had a positive correlation of 29.3% (95% CI: 27.7, 31.0) and sensitivity of 94.4% (95% CI: 84.6, 98.8). CT angiography had higher positive correlation across all clinical presentations. No dose-toxicity relationship was observed between contrast and renal function (R²: 0.008), nor was there a difference in incidence of contrast-induced nephropathy between CT angiography and RBC scintigraphy (P = .30).ConclusionsCT angiography has greater positive correlation to CA than RBC scintigraphy for assessing LGIB in active stable as well as hemodynamically unstable LGIB. As such, greater adoption of CT angiography may reduce the number of nontherapeutic CAs performed. Additional contrast associated with CT angiography does not result in increased nephrotoxicity.     

Scintigraphic evaluation of acute pancreatitis patients with 99mTc-HMPAO-labelled leukocytes

OBJECTIVE: To demonstrate the localization of leukocytes in the pancreas during acute pancreatitis and to evaluate the potential use of 99mTc-HMPAO-labelled leukocytes in the diagnostic assessment of patients with acute pancreatitis. METHODS: The study was performed with 20 patients (11 females, nine males; ranging in age from 26 to 86 years, mean 55 years). Labelled leukocyte scintigraphy using planar imaging was performed on all patients, seven of whom were also examined by single photon emission computed tomography (SPECT). According to Ranson criteria, 10 patients had mild pancreatitis (group A), six had severe pancreatitis (group B) and four had necrotic pancreatitis (group C). Twelve patients had biliary pancreatitis and the other eight patients had no obvious cause. RESULTS: All patients of group C, four of group B, two of group A had a positive leukocyte scan. The positive leukocyte scintigraphy value for the detection of a lethal course of acute pancreatitis was 100%; of a severe course, 66.7%; and of a mild course, 20%. These findings are statistically significant (P=0.005 in chi-squared tests result). The results of leukocyte scintigraphy compared with those of CT were also statistically significant (P=0.001 in chi-squared tests). All the patients diagnosed with pancreatic necrosis by CT had a positive leukocyte scan, but only three of 13 patients without pancreatic necrosis that could be detected by computed tomography had a positive leukocyte scan. CONCLUSIONS: There was a significant correlation between the severity of the disease and leukocyte infiltration. Considering these results, we believe that leukocyte infiltration in acute pancreatitis can be demonstrated rapidly and accurately and by noninvasive 99mTc-HMPAO labelled leukocyte scintigraphy.     

99mTc-PEG liposomes for the scintigraphic detection of infection and inflammation: clinical evaluation.

Polyethyleneglycol (PEG) liposomes have been shown to be excellent vehicles for scintigraphic imaging of infection and inflammation in various experimental models. In this article we report on a series of patients with possible infectious and inflammatory disease in whom the performance of 99mTc-PEG liposomes was evaluated. The results of 99mTc-PEG liposome scintigraphy were directly compared with those of 111In-immunoglobulin G (IgG) scintigraphy. METHODS: Thirty-five patients (22 men, 13 women; mean age, 51 y; range, 20-76 y), suspected of having infectious or inflammatory disease, received 740 MBq 99mTc-PEG liposomes intravenously. Imaging was performed at 4 and 24 h after injection. Patients received 75 MBq 111In-IgG 24 h after administration of the liposomes. The scintigraphic results were compared and verified by culture, biopsy, surgery, and follow-up of at least 6 mo. RESULTS: Of the 16 proven infections and inflammations, 15 were detected by 99mTc-PEG liposome scintigraphy: soft-tissue infection (n = 3), septic arthritis (n = 3), autoimmune polyarthritis (n = 2), infected hip prosthesis (n = 1), infected osteosynthesis (n = 1), spondylodiscitis (n = 1), infected aortic prosthesis (n = 1), colitis (n = 1), abdominal abscess (n = 1), and pneumonia (n = 1). 99mTc-PEG liposome and 111In-IgG scintigraphy both missed 1 case of endocarditis. In addition, an 111In-IgG scan of a patient with mild soft-tissue infection was false-negative. Concordantly false-positive scans were recorded from 2 patients, both with uninfected pseudarthrosis and focal signs of sterile inflammation. During liposomal administration, 1 patient experienced flushing and chest tightness, which rapidly disappeared after lowering the infusion rate. No other adverse events were observed. CONCLUSION: This clinical evaluation of 99mTc-PEG liposomes shows that focal infection and inflammation can be adequately imaged with this new agent. The performance of 99mTc-PEG liposomes is at least as effective as that of 111In-IgG. With the simple and safe preparation and the physical and logistic advantages of a 99mTc label, 99mTc-PEG liposomes could be an attractive agent for infection or inflammation imaging.     

Evaluation of white cell scintigraphy using indium-111 and technetium-99m labelled leucocytes

Indium-111 oxine labelled leucocyte (¹¹¹In oxine leucocyte) scintigraphy is the test of choice in detecting occult infection and localising focal inflammation. ¹¹¹In oxine labelling is technically difficult and expensive and leucocyte labelling with technetium-99m stannous colloid (^99mTc Sn colloid) has been considered to be an alternative. Leucocytes from 40 cases referred for investigation of occult infection or localisation of inflammation were simultaneously labelled with ¹¹¹In oxine and ^99mTc Sn colloid with dual isotope acquisition performed at 1, 3 and 24 h. Twenty-four hour ^99mTc Sn colloid scans were corrected for ¹¹¹In downscatter. Each case was independently interpreted by two experienced observers. Twentyone patients demonstrated positive ¹¹¹In oxine leucocyte scans. Using ¹¹¹In oxine leucocyte scans as the gold standard, ^99mTc Sn colloid leucocyte scanning had an overall sensitivity of 86% and a specificity of 95%. Clinical follow-up verified that three patients had false negative ^99mTc Sn colloid leucocyte scans and one patient had a false positive. Further clinical evaluation of ^99mTc Sn colloid labelled leucocytes is required before they can become a reliable replacement for ¹¹¹In oxine leucocytes. Correspondence to: S. Boyd     

Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy

Purpose Silent myocardial ischaemia—as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain—is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion.Methods The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, ^99mTc-sestamibi, ²⁰¹Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS).Results Abnormal MPS (SSS4) was observed in 49 (37%) patients (SSS=4.9±8.4, SDS=2.4±4.7), reversible perfusion defects (SDS2) in 40 (30%) patients [SSS=13.3±10.9; SDS=8.0±5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21–42%) presented reversible defects (SSS=13.9±11.3; SDS=7.4±1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress [odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02).Conclusion Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify these patients with a potentially increased risk of cardiovascular events.     

Prevalence of myocardial ischaemia as assessed with myocardial perfusion scintigraphy in patients with diabetes mellitus type 2 and mild anginal symptoms

Purpose To determine the prevalence and predictors of reversible myocardial perfusion defects, indicative of myocardial ischaemia, in patients with mild, stable anginal complaints [Canadian Cardiovascular Society classification (CCS) I–II/IV] and diabetes mellitus type 2 (T2DM). Methods A total of 329 patients with T2DM and stable, mild anginal symptoms (CCS I–II/IV) underwent myocardial perfusion scintigraphy. Perfusion images were assessed using a five-point (semi)-quantitative scoring system according to a 17-segment myocardial model. Results One-hundred and fifty-six (47%) patients showed reversible myocardial perfusion defects defined as a summed difference score of ≥3. Male gender [odds ratio (OR) 2.28, 95% CI 1.4–3.71, p=0.001], previous myocardial infarction (MI) without revascularisation (OR 3.04, 95% CI 1.28–7.24, p=0.01), and the use of two or more classes of anti-anginal medication (OR 2.36, 95% CI 1.48–3.76, p<0.001) were independent predictors for the presence of reversible defects. By contrast, lipid-lowering therapy reduced the possibility of reversible perfusion defects (OR 0.56, 95% CI 0.33–0.95, p=0.03). Conclusion Approximately half of the patients with mild, stable angina pectoris and T2DM showed evidence of myocardial ischaemia. Male gender, previous MI and the use of anti-anginal medication were positive predictors and lipid-lowering therapy was a negative predictor for the results of the scintigraphic stress test.     

Diagnostic performance of planar scintigraphy using 99mTc-MIBI in patients with secondary hyperparathyroidism: a meta-analysis

Objective

Parathyroid scintigraphy using ^99mTc-MIBI is not currently considered a valuable diagnostic tool for the localization of involved glands in patients with secondary hyperparathyroidism (SHPT). However, published data about its diagnostic accuracy are discordant and a meta-analysis about this topic is still lacking. The aim of our study is to meta-analyze the published data about the diagnostic performance of ^99mTc-MIBI parathyroid scintigraphy in patients with SHPT.

Methods

A comprehensive computer literature search of studies published in PubMed/MEDLINE, Scopus and Embase databases through September 2011 and regarding the diagnostic accuracy of ^99mTc-MIBI parathyroid scintigraphy in patients with SHPT was carried out. Only articles in English language in which at least 10 patients with SHPT underwent planar ^99mTc-MIBI parathyroid scintigraphy were selected. Pooled sensitivity, pooled specificity and area under the ROC curve on a per lesion-based analysis were calculated to measure the diagnostic accuracy of ^99mTc-MIBI parathyroid scintigraphy in SHPT patients.

Results

Twenty-four studies comprising 471 patients were included in this meta-analysis. The pooled sensitivity and specificity of ^99mTc-MIBI parathyroid scintigraphy in detecting hyperplastic glands in SHPT patients were 58?% [95?% confidence interval (95?% CI) 52?C65?%] and 93?% (95?% CI 85?C100?%), respectively, on a per lesion-based analysis. Area under ROC curve was 0.75.

Conclusions

In patients with SHPT and diffuse or nodular hyperplasia, planar parathyroid scintigraphy using ^99mTc-MIBI has demonstrated an inadequate diagnostic accuracy. Therefore, it should not be considered as a first-line diagnostic imaging method in the pre-surgical detection of hyperplastic parathyroid glands.