Detection of osteomyelitis at fracture nonunion sites: comparison of two scintigraphic methods

Forty-nine patients with 50 fracture nonunions 4-48 months after injury underwent technetium-99m methylene diphosphonate (99mTc-MDP) scintigraphy on day 1, combined 99mTc-MDP and indium-111 leukocyte (111In-WBC) scintigraphy on day 2, and gallium-67 (67Ga) scintigraphy on day 3. The results were compared to evaluate the relative abilities of these scintigraphic techniques to detect osteomyelitis. Nine patients had clinical evidence of infection at the time of imaging, and 40 patients (41 fractures) did not. Open-biopsy cultures were performed at all fracture sites and were positive at 21 (42%) of the 50 sites. Combined 99mTc-MDP/111In-WBC images were interpreted with the use of two criteria. A positive study by the first criterion required 111In-WBC localization in the region of the nonunion fracture. A positive study by the second criterion required 111In-WBC localization in bone at the fracture site. The first criterion yielded a sensitivity of 84%, specificity of 72%, and accuracy of 74%; the specificity improved to 97% with an accuracy of 88% when the second criterion was used. Ten (25%) of the 40 patients thought not to have osteomyelitis by clinical criteria at the time of imaging had true-positive 99mTc-MDP/111In-WBC studies by biopsy culture results. Gallium-67 studies were interpreted as nondiagnostic if localization of radioisotope at fracture sites was equal to that with 99mTc-MDP, positive if 67Ga localization was greater than that of 99mTc-MDP, and negative if it was less than that of 99mTc-MDP. Twenty-one 67Ga studies were interpreted as nondiagnostic; 11 (52%) of the 21 had culture-positive fracture sites. The accuracy of 67Ga/99mTc-MDP imaging was 39%. Combined 99mTc-MDP/111In-WBC imaging is useful in the detection of osteomyelitis at fracture nonunion sites and improves the specificity of 111In-WBC imaging by differentiating inflammation/infection in adjacent soft tissue from osteomyelitis at the fracture site. Gallium-67 with 99mTc-MDP imaging is not sufficiently reliable in this clinical setting to be useful as an indicator for osteomyelitis.     

The roles of gallium-67 scintigraphy, ultrasonography, and computed tomography in the detection of abdominal abscesses

The evaluation of patients with suspected abdominal abscesses begins with a history and careful physical examination. Gallium-67 (67Ga) scintigraphy, ultrasonography (US), and computed tomography (CT) are utilized only after other routine investigations have failed to localize the abscess. All three modalities are reliable for the detection of abdominal abscesses. The decision regarding which of these three diagnostic tests to use in a particular patient rests upon clinical considerations. If the patient has acute localizing signs and symptoms, 67Ga should not be used initially. In this type of patient, rapid diagnosis is best provided by either US or CT. Further radiologic investigation may be terminated if the CT or US findings are characteristic of an abscess. A 67Ga scan should be performed in a patient with acute localizing signs and symptoms if the initial CT or US is negative. In a patient with nonlocalizing signs and symptoms, 67Ga imaging should be employed as the first procedure since the entire body is easily surveyed. If the 67Ga images are abnormal, then CT or US should be utilized for further lesion characterization. This diagnostic approach will optimize the rapidity of patient evaluation and will minimize diagnostic errors.     

111In-DOTA- dPhe1-Tyr3-octreotide, 111In-DOTA-lanreotide and 67Ga citrate scintigraphy for visualisation of extranodal marginal zone B-cell lymphoma of the MALT type: a comparative study

Somatostatin receptor (SSTR) scintigraphy and gallium-67 citrate ((67)Ga) scintigraphy have been used for visualisation of Hodgkin's lymphoma and non-Hodgkin's lymphoma. However, experience with B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) type is very limited. The aim of this study was to prospectively compare the (67)Ga scintigraphy results with those obtained by (111)In-DOTA- dPhe(1)-Tyr(3)-octreotide ((111)In-DOTA-TOCT) and (111)In-DOTA-lanreotide ((111)In-DOTA-LAN) scintigraphy in patients with proven MALT-type lymphoma. Comparative scintigraphic examinations using (67)Ga, (111)In-DOTA-TOCT and (111)In-DOTA-LAN were performed in 18 patients (11 female and 7 male, median age 64+/-15 years) with histologically verified MALT-type lymphomas of various origin. Planar and single-photon emission tomography imaging acquisitions were performed after injection of a mean dose of 185+/-26 MBq (67)Ga and 165+/-20 MBq (111)In-DOTA-TOCT or (111)In-DOTA-LAN. All scintigraphic results were correlated with other conventional examinations including gastroscopy, colonoscopy, endosonoscopy, ophthalmologic investigation, CT of the thorax and abdomen and bone marrow biopsy. This comparative study showed that (67)Ga scintigraphy found abnormalities in 10 of 16 patients (63%) and detected 18 of 31 clinically involved sites (58%), but was false positive in three patients. (111)In-DOTA-TOCT found abnormalities in 9 of 15 patients (60%) and detected 15 of 27 clinical lesions (56%); it was false positive in two patients. (111)In-DOTA-LAN scintigraphy showed abnormalities in 7 of 11 patients (64%) and found 12 of 22 clinical lesions (55%). False-positive (111)In-DOTA-LAN scan results were found in two patients. For supra-diaphragmatic lesions, (67)Ga scintigraphy detected 12 of 16 sites (75%). (111)In-DOTA-TOCT scintigraphy revealed 7 of 15 lesions (47%). (111)In-DOTA-LAN showed 6 of 12 positive sites (50%). For infra-diaphragmatic involvement, the sensitivities of (67)Ga, (111)In-DOTA-TOCT and (111)In-DOTA-LAN were 40%, 67% and 60%, respectively. It is concluded that MALT-type lymphoma can be visualised by (67)Ga, (111)In-DOTA-TOCT and (111)In-DOTA-LAN scintigraphy. Although there were no statistically significant differences in patient-related and site-related sensitivities when using (67)Ga compared with (111)In-DOTA-TOCT and (111)In-DOTA-LAN, the sensitivity of (67)Ga tended to be superior to that of (111)In-DOTA-TOCT and (111)In-DOTA-LAN for supra-diaphragmatic lesions but inferior for infra-diaphragmatic involvement. In selected cases, the combination of (67)Ga and (111)In-DOTA-LAN or (111)In-DOTA-TOCT may increase the diagnostic efficiency in patients with MALT-type lymphoma.     

Computed tomography and 67Ga citrate radionuclide imaging for evaluating suspected abdominal abscess.

A retrospective analysis of the results of 67Ga citrate radionuclide imaging and computed tomography (CT) in 45 patients with suspected abdominal abscess was conducted to determine the mertis of each method. Both techniques were highly sensitive in detecting abdominal abscesses, and often provided complementary and supplementary diagnostic information; their combined use many times offset the limitations of each method used alone. Guidelines are suggested that permit rapid evaluation, while limiting diagnostic errors, when using 67Ga citrate radionuclide imaging and CT in the presence or absence of localizing symptoms and signs.     

Indium-111-leukocyte imaging in acute cholecystitis

Eleven patients with suspected acute cholecystitis underwent sequential 99mTc-iminodiacetic derivative (IDA) and 111In-white blood cell (WBC) imaging to determine if 111In-WBCs accumulate within an acutely inflamed hemorrhagic gallbladder wall and, thus, could be employed as a reasonable alternative to 99mTc-IDA scintigraphy in detecting acute cholecystitis. Seven patients had surgically confirmed acute cholecystitis. Of these cases, five had a true-positive 99mTc-IDA and 111In-WBC, one an indeterminate 111In-WBC and true-positive 99mTc-IDA, and one a true-positive 111In-WBC and false-negative 99mTc-IDA scan. The remaining four patients did not have acute cholecystitis. All visualized their gallbladder within 1 hr after 99mTc-IDA administration and none had 111In-WBC gallbladder wall uptake. Both 111In-WBC and 99mTc-IDA scintigraphy accurately detected acute cholecystitis: hepatobiliary scintigraphy demonstrated a cystic duct obstruction and 111In-WBC imaging detected the inflammatory infiltrate within the gallbladder wall. The sensitivity and specificity of each was 86% and 100%, respectively.     

Early 67Ga scintigraphy for the localization of abnominal abscesses.

Sixty patients suspected of having abdominal abscesses were evaluated by early and delayed 67Ga scintigraphy. The 67Ga scintigraphs obtained 6 hr after injection correctly localized 18 of 20 abdominal or retroperitoneal abscesses. An additional 13 patients with abnormal scintigraphs had clinically established infections. In no instance was an abscess or inflammatory focus present on delayed scintigraphs that was no evident on the 6-hr study. Two false-positive and two false-negative studies were recorded. Early 67Ga scintigraphy is warranted in patients with suspected abdominal abscesses.     

The role of gallium-67 scan in defining the extent of disease in an endemic deep mycosis,paracoccidioidomycosis: a predominantly multifocal disease

The tools currently used to evaluate the extent of paracoccidioidomycosis (PCM) may be of limited value in detecting subclinical lesions. The aim of this study was to verify the role of gallium-67 whole-body scan in evaluating the extent of disease of 65 patients with active PCM. The (67)Ga scan findings were compared with the results of clinical evaluation, chest radiography and/or high-resolution computed tomography (CT), abdominal ultrasound (US) or CT, laryngoscopy, CT or magnetic resonance imaging (MRI) of the head, and technetium-99m methylene diphosphonate bone scan, obtained before treatment. Clinically unsuspected lesions were detected by imaging procedures in 21 patients (32%), mainly in the lungs (n=11), adrenals (n=6), and superficial (n=3) and deep lymph nodes (n=14). (67)Ga scan detected 100% of the cases with subclinical involvement in the lungs. Scintigraphy was superior to chest radiography in demonstrating lung disease (94% vs 81%). The lymphatic lesions were demonstrated by (67)Ga scan in all the clinically suspected cases and in nearly all unsuspected cases, and also revealed more extensive involvement than was clinically suspected in many of them. There was good agreement between (67)Ga scan and the other imaging procedures for the initial detection of thoracic and abdominal lymph nodes and bone involvement. (67)Ga imaging detected most cases of laryngopharyngeal disease with active inflammatory lesions found at indirect laryngoscopy. On the other hand, (67)Ga scan failed to demonstrate most of the adrenal and CNS lesions detected by abdominal US/CT and head CT/MRI. In conclusion, (67)Ga imaging is a useful tool for evaluating the location and extent of suspected and unsuspected lesions in PCM. It could serve as a screening method before the use of other diagnostic procedures, particularly in the detection of lung, superficial and deep lymph node and bone involvement.     

Accumulation of indium-111-labeled neutrophils and gallium-67 citrate in rabbit abscesses

A rabbit abscess model was developed to study the effect of abscess age on the accumulation of indium-111-labeled neutrophils ([111In]N) versus gallium-67 citrate (67Ga). Abscesses 1-2 hr, 6-8 hr, 24 hr, and 7 days old were induced by subcutaneous injection of autoclaved colon contents prior to i.v. administration of either [111In]N or 67Ga. Radioactivity in the abscesses was determined 48 hr postinjection. Accumulation of [111In]N was inversely proportional to abscess age. Seven-day-old abscesses were inconsistently seen on [111In]N scans. In contrast, 67Ga accumulation was not affected by abscess age and all abscesses could be identified on a scan 48 hr postinjection. Scans with [111In]N were clearly superior to 67Ga scans for demonstrating early abscesses. Since 67Ga accumulated to a greater extent than [111In]N in abscesses 7 days old, it may be a superior imaging agent for older abscesses.     

A case of retroperitoneal extramedullary plasmacytoma with multiple metastases

We investigated a patient with extramedullary plasmacytoma in the retroperitoneal space with multiple metastases using abdominal CT scan and 67Ga scintigraphy. Abdominal enhanced CT revealed the retroperitoneal tumor mimicking lymphoma. 67Ga scintigraphy showed multiple tumor localization. We could detect retroperitoneal extramedullary plasmacytoma with multiple metastases using 67Ga scintigraphy. This retroperitoneal tumor may appear similar to lymphoma on CT.     

Indium-111-oxine labeled platelet and leucocyte scintigraphy for diagnosis of thrombi and inflammation

There were many studies for diagnosis of localization and activity of thrombi and inflammation using indium-111-oxine labeled platelet (In-plt) and leucocyte scintigraphy (In-WBC), respectively. The study using these techniques is decreasing recently, because other diagnostic modarities have been developed and the techniques of these scintigraphy are complicated. However, because these scintigraphy are noninvasive, it is expected that these are widely applied to the clinical diagnosis and follow up. 1. Platelet scintigraphy can visualized thrombi and distinguish the activation of platelet aggregation. There were many reports and reviews. I reviewed recent studies in cardiovascular diseases and our cases. 2. Leucocyte scintigraphy (In-WBC) is usually used for the detection of inflammation. Furthermore, it is possible that In-WBC can detect inflammation of the arteriosclerotic lesion of the aortic wall. I introduced our studies of In-WBC in aortic aneurysma and aortic dissection. The In-WBC maybe useful for detection of inflammation of the aortic aneurysma and evaluation of prognosis of aortic dissection.     

Gallium-67 scintigraphy in lymphoma: is there a benefit of image fusion with computed tomography?

The usefulness and complementarity of gallium (67Ga) scintigraphy and computed tomography (CT) in the management of patients with lymphoma have been extensively demonstrated. Owing to a lack of anatomical landmarks and physiological distribution of the tracer, precise localisation of abnormalities on 67Ga scintigraphy can be difficult. As fusion imaging techniques between single-photon emission tomography (SPET) and CT have been developed recently, we investigated whether use of CT/67Ga SPET fusion imaging could help in the interpretation of 67Ga scintigraphy. From November 1999 to May 2001, 52 consecutive fusion studies were performed in 38 patients [22 patients with Hodgkin's disease (HD) and 16 patients with non-Hodgkin's lymphoma (NHL)] as part of pre-treatment staging (n=13), treatment evaluation (n=20) or evaluation of suspected recurrence (n=19). 67Ga scintigraphy was carried out 2 and 6 days following the injection of 185-220 MBq 67Ga citrate. On day 2, 67Ga SPET and CT were performed, focussing on the chest and/or the abdomen/pelvis. Data from each imaging method were co-registered using external markers. 67Ga scintigraphy and CT were initially interpreted independently by nuclear medicine physicians and radiologists. CT/67Ga SPET fusion studies were then jointly interpreted and both practitioners indicated when fusion provided additional information in comparison with CT and 67Ga SPET alone. Image fusion was considered to be of benefit in 12/52 (23%) studies which were performed for initial staging (n=4), treatment evaluation (n=4) or evaluation of suspected recurrence (n=4). In these cases, image fusion allowed either confirmation and/or localisation of pathological gallium uptake (n=10) or detection of lesions not visible on CT scan (n=2). Fusion was relevant for discrimination between osseous lesions and lymph node involvement adjacent to bone, especially in the thoracic and lumbar spine and pelvis. In the abdomen and pelvis, fusion helped to differentiate physiological bowel elimination from abnormal uptake, and assisted in precisely locating uptake in neighbouring viscera of the left hypochondrium, including the spleen, left liver lobe, coeliac area, stomach wall and even the splenic flexure. At the thoracic level, fusion also proved useful for demonstrating clearly the relationships of abnormal foci to the pleura, hepatic dome, mediastinum, ribs or thoracic spine. Clinical management was altered by fusion imaging in one patient (chemotherapy was given instead of radiotherapy) and was potentially affected in three other patients (in that, in conjunction with other factors, the results of fusion imaging had an influence on the decision regarding use of irradiation and especially the treatment volume). In conclusion, CT/67Ga SPET fusion imaging allowed precise localisation of gallium uptake and correct attribution to the involved viscera, thereby altering the diagnosis in 20%-25% of studies in comparison with CT and 67Ga SPET analyses alone. CT/67Ga SPET fusion therefore appears valuable in facilitating the interpretation of 67Ga scintigraphy and we recommend its use in patients with lymphoma when CT and 67Ga scintigraphy are planned.     

Detection of subacute infectious foci with indium-111-labeled autologous leukocytes and indium-111-labeled human nonspecific immunoglobulin G: a prospective comparative study

In 35 patients suspected of an infectious focus, the outcome of scintigraphy with 111In-labeled autologous leukocytes (WBC) and 111In-labeled human nonspecific immunoglobulin G (IgG) was evaluated in a prospective comparative study. Clinical, roentgenologic and microbiologic findings were considered to be proof of the presence of infection or inflammation. In this group of patients with mainly subacute infections, 111In-IgG scintigraphy performed significantly better than 111In-WBC scintigraphy, especially in infections of the locomotor system, but also in various soft-tissue infections. Both techniques showed disappointing results in patients with disseminated yersinia infection and in some patients with tuberculosis. Overall sensitivity and specificity was 74% and 100% for 111In-IgG scintigraphy and 52% and 78% for 111In-WBC scintigraphy, respectively.     

Diagnosis of synthetic vascular graft infection: comparison of CT and gallium scans

Sixteen patients were examined with both abdominal CT and 67Ga scintigraphy for suspected synthetic vascular graft infection. Two patients were studied twice, yielding a total of 18 paired tests. A total of 25 grafts were analyzed. The results of CT and 67Ga scintigraphy were compared for grafts in specific anatomic locations including the retroperitoneum, groin, and abdominal wall, and for combined sites. When all locations were considered as a group, CT had a sensitivity of 100% and specificity of 72%; 67Ga scintigraphy had a sensitivity of 78% and specificity of 94%. 67Ga scintigraphy proved to be more specific than CT (p less than .05) for combined sites, but no significant difference in sensitivities was demonstrated, possibly because of the small number of infected grafts in our study. No differences in sensitivities or specificities were statistically significant when grafts in individual anatomic sites were analyzed. Since no significant difference between the sensitivities of CT and 67Ga scanning was demonstrated in our study, although the number of infected grafts was small, CT is recommended as the initial examination when graft infection is suspected because it can be performed immediately. 67Ga scintigraphy remains an important complementary test, adding specificity to the diagnostic workup.     

Clinical relevance of gallium-67 scintigraphy in lymphoma before and after therapy

The clinical impact of gallium-67 scintigraphy before and after therapy for lymphoma remains controversial. The aims of this study were: (1) to compare the staging of lymphoma by 67Ga scintigraphy only with staging by clinical examination and conventional imaging (CI), and (2) to analyse the clinical relevance of both 67Ga imaging and CI after treatment. From March 1995 to November 1998, 86 67Ga scintigraphy studies were performed in 62 patients with Hodgkin's disease (n=52) or non-Hodgkin's lymphoma (n=10). 67Ga scintigraphy was performed at diagnosis (n=44) or after therapy (n=42) using 185-220 MBq 67Ga citrate and planar and single-photon emission tomography (SPET) studies. Treatment comprised radiotherapy, chemotherapy or combined modalities. CI included plain chest radiography, computed tomography (CT) of the chest and abdomen/pelvis, ultrasound of the abdomen, lymphography, bone marrow biopsy and, when necessary, magnetic resonance imaging (MRI) and bone scintigraphy. For individual suspected sites of disease before treatment, complete agreement between clinical examination and CI on the one hand and 67Ga scintigraphy on the other hand was observed in 25/44 patients (57%; 95% confidence interval 41%-72%). Clinical examination and CI showed more sites than did 67Ga scintigraphy in 12/44 patients (27%) and 67Ga imaging demonstrated more sites than CI in 6/44 patients (11%). The clinical stage of the disease as assessed using 67Ga scintigraphy only was in agreement with that using all diagnostic procedures in 34/44 patients (77%; 95% confidence interval 62%-89%). Compared with CI staging, 67Ga scintigraphy downstaged seven patients (16%) and upstaged three (7%). 67Ga scintigraphy downstaged mainly because of the limited value of the technique below the diaphragm and upstaged owing to the good sensitivity in the lung. After therapy, both CI and 67Ga scintigraphy were normal in 11 patients. All but one of these patients were in complete remission after a median follow-up of 31 months. In contrast, radiological residual mass was observed in 31/42 patients. 67Ga imaging was normal in 22/31 (71%); 17 of these 22 patients, including nine with a large residual mass (> or =2 cm), were in complete remission after a median follow-up of 32 months, while four suffered relapses 8-45 months later. The cause of death remained unknown in one patient. 67Ga scintigraphy showed abnormal uptake in 9 of the 31 patients with a large residual mass. Active disease was demonstrated in eight patients and one patient was in complete remission 30 months thereafter. Our data show that 67Ga imaging cannot replace CI in initial staging but can demonstrate additional individual sites of disease in more than 10% of patients and can lead to clinical upstaging with potential prognostic and therapeutic consequences. After therapy, 67Ga scintigraphy has a clinical impact when radiological abnormalities persist because it can either avoid unnecessary complementary treatment or confirm the need to change treatment modalities.     

Indium-111-leukocyte/technetium-99m-MDP bone and magnetic resonance imaging: difficulty of diagnosing osteomyelitis in patients with neuropathic osteoarthropathy

Fourteen patients (16 sites) with clinical and/or radiographic evidence of neuropathic osteoarthropathy (Charcot joints) were evaluated with combined indium-111-leukocyte (111In-WBC) and technetium-99m-methylene diphosphonate (99mTc-MDP) bone imaging for suspected osteomyelitis. Magnetic resonance (MR) images were obtained in seven patients. Using a positive bone culture as the criterion for the presence of osteomyelitis, there were four true-positive studies, six true-negative sites, and one false-negative 111In-WBC study. Five of 16 sites (31%) had false-positive 111In-WBC uptake at noninfected sites. There were four true-positive and three false-positive MR studies. All false-positives showed at least moderately abnormal findings by both techniques at sites of rapidly progressing osteoarthropathy of recent onset. In this preliminary study, both techniques appear to be sensitive for detection of osteomyelitis, and a negative study makes osteomyelitis unlikely. However, the findings of 111In-WBC/99mTc-MDP and MR images at sites of rapidly progressing, noninfected neuropathic osteoarthropathy may be indistinguishable from those of osteomyelitis.     

Iodine-131 metaiodobenzylguanidine scintigraphy for localization of lesions in children with neuroblastoma: comparison with computed tomography and ultrasonography

Iodine-131 metaiodobenzylguanidine (MIBG) scintigraphy, computed tomography (CT) and ultrasonography (US) were used to localize tumour lesions in 28 children with histologically proven neuroblastoma. Overall, a total of 73 lesions were detected on imaging studies. MIBG scintigraphy, CT and US localized 63 (86%), 49 (67%) and 36 (49%) of these lesions, respectively. The findings of the three imaging techniques were concordant in respect of only 31 (42%) of the lesions. The best agreement among MIBG scintigraphy, CT and US was observed for abdominal lesions (the techniques were concordant for 22 of 23 lesions, i.e. 96%). MIBG scintigraphy detected nine out of ten (90%) liver metastases, but agreement with CT and US was observed in only six instances (60%). The imaging findings were concordant in respect of only two (33%) out of six lymph node metastases; the MIBG scan was normal in the other four cases. Imaging agreement was observed for a lesion located in the pelvis. MIBG and CT findings were concordant in four lesions located in the chest, but US was not performed. MIBG scintigraphy depicted the majority (96%) of the skeletal lesions (23/24); CT showed five of these, but, again, US was not performed. The imaging findings were not concordant as regards the remaining five lesions located in different anatomical sites. The results indicated that MIBG imaging is more sensitive that CT and US in localizing the majority of neuroblastoma lesions. Since the metastatic spread of neuroblastoma is unpredictable, we recommend MIBG scintigraphy as the initial imaging modality for staging of these patients. US and, particularly, CT should be performed thereafter to clarify the anatomical detail of the lesions detected on MIBG scans, or when MIBG findings are normal or equivocal.     

Gallium-67 imaging in abdominal disease

Gallium-67 imaging is useful for detecting sites of intra-abdominal inflammation, including subphrenic abscesses, postoperative infection, pyelonephritis or perinephric abscesses, and peritonitis. Positive images may be obtained within several hours of injection, but are more reliable at 24 hr. The results may be used to guide ultrasound or computed tomography studies, which give a detailed anatomic picture of the abscess. Gallium-67 imaging has also been used to detect abdominal neoplasms, but results are less impressive. Abdominal lymphoma is detected in just over 50% of sites. Gastrointestinal, renal, and gynecologic neoplasms are detected even less frequently. However, 67Ga is useful for detecting recurrence of 67Ga-avid neoplasms, and has been reliable in detecting hepatomas and nodal spread of seminoma. When used selectively in patients with neoplastic disease and suspected abscesses, 67Ga is an effective method for diagnosing abdominal disease.     

Retrospective review: usefulness of a number of imaging modalities including CT, MRI, technetium-99m pertechnetate scintigraphy, gallium-67 scintigraphy and F-18-FDG PET in the differentiation of benign from malignant parotid masses

Objective The aim of this study is to evaluate an imaging approach using computed tomography (CT), magnetic resonance imaging (MRI), technetium-99m pertechnetate scintigraphy (^99mTc pertechnetate scintigraphy), gallium-67 scintigraphy (⁶⁷Ga scintigraphy) and fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET). Material and Methods We reviewed retrospectively 59 patients with parotid masses. CT, MRI,⁶⁷Ga scintigraphy,^99mTc pertechnetate scintigraphy, and¹⁸F-FDG PET were performed. Results All of the benign tumors had smooth margins on CT and MRI. Patients with inflammatory lesions and malignant lesions showed well-defined margins or ill-defined margins. All Warthin's tumors showed high technetium accumulation. Many of malignant tumors showed high FDG accumulation. Both pleomorphic adenomas and Warthin's tumors showed high accumulation in some cases on¹⁸F-FDG PET. Among 15 patients with pleomorphic adenoma, 14 patients showed marked hyperintensity relative to CSF on T2-weighted images and partial enhancement on contrast-enhanced T1-weighted images. Combination of several imaging modarity offered usefulness of differential diagnosis for parotid masses. Conclusion An efficient combination of imaging methods may be helpul for achieve the correct diagnosis.     

Gallium-67 scintigraphy: a cornerstone in functional imaging of lymphoma

Until recently, gallium-67 scintigraphy (GS) has been the best available functional imaging modality for evaluating patients with non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). The diagnostic accuracy of GS in detecting lymphoma is based on optimisation of the imaging protocol, knowledge of potential physiological and benign sites of (67)Ga uptake, and the Ga avidity characteristics of the individual lymphoma. As (67)Ga is a tumour viability agent, the role of GS is primarily at follow-up. A residual mass persisting on CT after treatment poses a common clinical dilemma: it may indicate the presence of viable lymphoma, which requires further treatment, or it can be benign, consisting of only fibrotic and necrotic tissues. GS can successfully differentiate between these conditions. Routine follow-up with GS may allow early diagnosis of recurrence and early institution of treatment. Reversion of a positive GS to a negative test, and the rapidity with which this occurs has a high predictive value for the outcome of the individual patient. Lymphoma showing a normal GS early during treatment has a better prognosis than lymphoma with persistence of pathological findings. Other tumour-seeking single-photon emitting agents, such as thallium-201, technetium-99m methoxyisobutylisonitrile and indium-111 octreotide, have been investigated in lymphoma, primarily as an alternative to GS in specific clinical settings, but are of limited value. The role of radioimmunoscintigraphy is gaining importance in conjunction with radioimmunotherapy. Fluorine-18 fluorodeoxyglucose (FDG) imaging of lymphoma using either dedicated or camera-based PET systems is gradually replacing GS for assessment of lymphoma. FDG overcomes some of the limitations of GS while sharing its tumour viability characteristics. The extensive clinical knowledge and experience accumulated over three decades with GS in lymphoma provides a solid background as well as a model for the assessment of new functional imaging techniques.     

Non-traumatic abdominal emergencies: imaging and intervention in sepsis

Cross-sectional imaging, in particular CT, has become the main method of detecting abdominal collections. Indium-labelled white-cell scintigraphy and gallium scintigraphy are reserved for patients in whom there is a high clinical suspicion of abdominal sepsis but CT has not revealed a source of sepsis. Scintigraphy is also used in patients with suspected vascular graft infections or suspected infected hip prostheses. Percutaneous abscess drainage (PAD) has revolutionised the treatment of abdominal abscesses over the past 20 years, with repeat laparotomy for postoperative abscesses becoming a rare event. Ultrasound or CT can be used to guide PAD. Choosing an access route that does not cross intervening organs is of crucial importance to the safe performance of PAD. The Trocar or Seldinger techniques can be used with equal success. The cavity should be aspirated until dry and irrigated with saline. Repeat imaging after drainage is helpful to detect any undrained locules. PAD endpoints include patient defervescence, reduction in white blood cell count and catheter drainage of less than 10 ml per day. Details regarding PAD in specific abdominal regions are discussed. Success rates for PAD are high (close to 90%) in most abdominal organs. Slightly lower success rates are seen with PAD of pancreatic abscesses and abscesses associated with fistulas (60-85% success rates). Complication rates lie between 0% and 10%. Complications can be minimised by ensuring that the patient has broad spectrum antibiotic coverage before drainage, by carefully planning the access route and by ensuring diligent post-procedure care by radiology staff.