Comparison of magnetic resonance imaging and 67gallium scintigraphy in the evaluation of posttherapeutic residual mediastinal mass in the patients with Hodgkin's lymphoma

IntroductionDetection of residual disease following the completion of primary treatment in Hodgkin's lymphoma (HL) patients diagnosed with mediastinal tumor mass has an exceptional importance in the assessment of therapeutic response. Magnetic resonance imaging (MRI) and ⁶⁷gallium (⁶⁷Ga) scintigraphy can be used to identify active tumor tissue in the mediastinal residuum.AimsTo evaluate: the accuracy of MRI and ⁶⁷Ga scintigraphy in the prediction of clinical HL relapse/progression; congruence of findings and the probability of mediastinal disease relapse/progression regarding to the detection of active/inactive tissue by both imaging methods.Materials and methodsThirty HL patients with abnormal mediastinal tissue following the completion of primary treatment were examined by MRI and ⁶⁷Ga scintigraphy. Positive findings were: high signal intensity on unenhanced T2-weighted images on MRI and the abnormal accumulation of gallium on scintigraphy or SPECT. These findings were compared with the clinical follow-up.ResultsSensitivity, specificity, accuracy, positive and negative predictive values were: 75.0%, 96.2%, 93.3%, 75.0%, 96.2% in MRI and 50.0%, 88.5%, 83.3%, 40.0%, 92.0% in ⁶⁷Ga scintigraphy. Discrepant results concerning the mediastinal tissue activity were found in 3 of 30 patients (10%). No statistically significant differences were found between both imaging methods in sensitivity, specificity and accuracy. Estimated 2-years progression free survival (PFS) for patients without and with active residual mediastinal tissue by MRI was 96% and 25% (p = 0.0001), respectively. The probability of 2-years PFS in the cases with negative and positive findings on ⁶⁷Ga scintigraphy was 92% and 60% (p = 0.026), respectively.ConclusionAlthough MRI showed better results than ⁶⁷Ga scintigraphy in the assessment of residual mediastinal tissue activity in HL patients after primary treatment, the difference between these methods was not statistically significant. Both methods could be included in the standard restaging protocol.     

Staging and monitoring of malignant lymphoma of the bone: comparison of 67Ga scintigraphy and MRI.

The aim of this study was two-fold: to compare 67Ga scintigraphy with MRI (a) for the staging of malignant lymphoma of the bone and (b) with regard to accuracy in detecting residual disease after first-line chemotherapy for restaging. METHODS: Twenty-one patients with 36 malignant osseous lesions were examined, including 7 patients with primary or multifocal osseous lymphoma and 14 patients with malignant lymphoma and simultaneous or secondary involvement of the bone. After first-line therapy, MRI and 67Ga scintigraphy were performed on 13 patients. The remission status based on all clinical and radiological findings during the follow-up was used as the gold standard. RESULTS: The osseous lesions were located on the axial skeleton in 64% of patients and on the appendicular skeleton in 36%. 67Ga scintigraphy detected 77% of the osseous lesions examined by MRI. For restaging after first-line therapy, MRI had a sensitivity of 90% and a specificity of 80% when dynamic MRI information was included. There were several false-positive results as a result of the pathologic increase in signal intensity ratios of reactive hematopoietic regions after chemotherapy. For 67Ga scintigraphy, a sensitivity of 70% and a specificity of 93% were calculated. CONCLUSION: These data show that monitoring malignant lymphoma of the bone still presents diagnostic problems. Given the high sensitivity of MRI and the high specificity of 67Ga scintigraphy but the limited specificity of MRI and sensitivity of 67Ga scintigraphy, both methods are valuable but should be used as complementary diagnostic tools.     

Gallium scan in adolescents and children with Hodgkin's disease (HD). Treatment response assessment and prognostic value.

AIM: The aim of the present paper is to describe the accuracy of gallium ((67)Ga) scintigraphy in adolescents and children with Hodgkin's disease (HD). We have studied the diagnostic value of this nuclear imaging technique at disease presentation (staging) and its prognostic value based on changes in (67)Ga uptake observed after treatment (response assessment). METHODS: From April 1985 to July 1999 74 consecutive untreated patients with a median age of 13 y underwent (67)Ga scans 48-72 h after injection of 37-111 MBq of (67)Ga-citrate. Planar whole-body scintigraphy was performed, supplemented with single photon emission tomography (SPET) of the mediastinum from 1996 onwards. Three patients did not undergo further scintigraphic examination because they were treated with radical surgery. After the 1st examination 71 of the 74 patients were monitored by 1-3 (67)Ga scans during the course of their disease. All of them had at least one (67)Ga scintigraphy at the end of the induction phase of chemotherapy, before any other therapeutic regimens were planned. RESULTS: At disease presentation (67)Ga scintigraphy was positive in all patients, detecting 285 of 335 (85.0%) lymph nodal sites of disease. The best sensitivity was observed in the mediastinum (100%; 63/63) and the laterocervical supraclavicular region (85.6%; 125/146); it was lower for axillary (72.7%; 16/22) and retroperitoneal (68.7%; 11/16) lymph node masses. In detecting visceral involvement the sensitivity of (67)Ga scintigraphy was 66.6% (8/12) for lung and 80% (4/5) for bone involvement. Among 71 patients in follow-up, 2 showed rapid progression of disease during induction therapy while 69 patients were monitored for a long period. The response to therapy has been classified according to the changes observed on nuclear medicine or radiological images as complete response (CR) or partial response (PR). On the basis of (67)Ga scans 55 patients (72.4%) were considered as having a CR, while with radiological modalities (chest X-ray, CT, MRI) CR was observed in only 29 patients (40.8%). PR or progression was found with (67)Ga scintigraphy in 16 patients (22.5%) and with radiological modalities in 42 patients (59.1%). (67)Ga scan was concordant with clinical outcome in 97% (28/29). The diagnostic effectiveness of this imaging technique has been analysed by comparing the scintigraphic or radiological changes at the 1st scintigraphic/radiological follow-up examination after induction therapy with the clinical outcome. In this population the relapse rate was 50% (8/16) in the group that did not achieve a CR according to post-treatment (67)Ga scintigraphy, while it was only 10.9% (6/55) in the group that achieved a CR on the basis of scintigraphy findings. The overall survival (OS) and disease-free survival (DFS) were calculated by means of Kaplan-Meier cumulative survival plotting. When the 2 groups of patients with complete (CR) or incomplete normalisation (PR or progression) of (67)Ga scintigraphy were compared, both OS and DFS were found to be statistically different (p=0.0001 and p=0.0004, respectively). By contrast, no statistical difference was found when the radiological findings were considered as the criterion for assessment of tumour response. On the basis of X-ray results the relapse rate was 13.7% in patients with negative post-therapy findings and 23.8% in patients with positive radiological imaging. CONCLUSION: Our data demonstrate the high value of (67)Ga scintigraphy in HD staging in paediatric patients. In addition, evaluation of the (67)Ga uptake is very useful as a prognostic parameter; changes in (67)Ga uptake after therapy indicate a favourable prognosis, whereas children still positive on post-treatment (67)Ga scintigrams should be given more aggressive treatment.     

Camera-based FDG PET and 67Ga SPECT in evaluation of lymphoma: comparative study

PURPOSE: To compare gallium 67 (67Ga) scintigraphy and camera-based fluorodeoxyglucose (FDG) positron emission tomography (PET) in the evaluation of patients with lymphoma. MATERIALS AND METHODS: The performance of 67Ga scintigraphy and camera-based FDG PET in the detection of lymphoma was retrospectively evaluated and compared in 84 patients with lymphoma, with 219 suspected sites of disease. Eighty-nine percent of patients were examined during or after treatment. Camera-based FDG PET was initiated by equivocal characterization of the status of disease based on clinical, radiologic, and 67Ga scintigraphic assessment. Findings of 67Ga scintigraphy and camera-based FDG PET were compared on a per-patient and per-site basis for the whole group, for histologic subtypes, and for anatomic locations. Comparison of sensitivity, specificity, and accuracy between the two modalities for detection of lymphoma was performed with the McNemar test. RESULTS: There was a statistically significant difference in sensitivity, specificity, and accuracy of 67Ga scintigraphy and camera-based FDG PET at both patient- and site-based analysis. 67Ga scintigraphy helped to accurately define disease state in 63% of patients and in 33% of sites, compared with 83% and 87%, respectively, for camera-based FDG PET. For discordant findings between the two modalities, camera-based FDG PET findings were confirmed as true-positive in 71% and as true-negative in 92% of patients. Camera-based FDG PET had a significantly higher detection rate for both nodal and extranodal lymphoma sites. It provided accurate assessment of lymphoma involvement of the skeleton in 93% of sites compared with 29% for 67Ga scintigraphy and excluded active lymphoma in 10 67Ga-positive benign parahilar sites. CONCLUSION: In this selected group of patients with lymphoma, camera-based FDG PET allowed a significantly more accurate definition of active disease compared with that allowed with 67Ga scintigraphy.     

Hodgkin's disease: prognostic role of gallium scintigraphy after chemotherapy.

Evaluation of the response to therapy is important for optimal selection of treatment strategy in patients with Hodgkin's disease (HD). Refractory disease requires intensive high-dose chemotherapy, whereas unnecessary treatment should be avoided in patients in complete remission. The purpose of this study was to evaluate the contribution of gallium-67 scintigraphy in predicting the clinical outcome in patients with HD and mediastinal involvement on the basis of scan results at the end of chemotherapy. Seventy-four patients with HD and mediastinal involvement were retrospectively investigated with 67Ga scintigraphy 72 h after injection of 220 MBq 67Ga citrate (planar and single-photon emission tomographic studies) following the completion of chemotherapy. At the same time, they all underwent computed tomography (CT). Patients were followed up for an average of 63 months (range 28-124 months). The disease status was newly diagnosed disease in 64 of the patients and relapse in 10. Systemic symptoms were absent (A) in 34 cases and present (B) in 40 cases. Forty-one patients had stage I or II disease and 33 patients had stage III or IV disease. Twenty-two patients had bulky disease on initial diagnosis. At the end of chemotherapy, all 74 patients showed regression of the mass by more than 50% (50%-100%) on CT. Patients were divided into two groups according to the positivity or negativity of the gallium scan after chemotherapy: 61 patients had negative and 13 patients had positive gallium scans. In the gallium-negative group, 19.7% of the patients relapsed and 91.8% were alive at the end of the follow-up. Relapse occurred in 20% of the patients with residual mass and in 19.6% of the patients without residual mass. In the gallium-positive group, 84.6% of the patients had recurrent disease and 61.5% were alive after intensive chemotherapy. There was a statistically significant difference in overall survival between patients with positive and patients with negative gallium results (P=0.0034). Disease-free survival differed significantly between patients with positive and patients with negative gallium scans at the end of chemotherapy (P<0.0001). The relative risk of death was 5.2 and the relative risk of relapse was 11.3 for patients with positive gallium scans, in comparison to those with negative gallium scans. The positive and negative predictive values for predicting relapse were 85% and 87%, respectively. It is concluded that even if gallium scan is performed at the end of chemotherapy, it can predict outcome. Alternative therapy may be required on the basis of gallium scan results obtained after treatment.     

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.     

Hodgkin's disease: prognostic role of gallium scintigraphy after chemotherapy

Evaluation of the response to therapy is important for optimal selection of treatment strategy in patients with Hodgkin's disease (HD). Refractory disease requires intensive high-dose chemotherapy, whereas unnecessary treatment should be avoided in patients in complete remission. The purpose of this study was to evaluate the contribution of gallium-67 scintigraphy in predicting the clinical outcome in patients with HD and mediastinal involvement on the basis of scan results at the end of chemotherapy. Seventy-four patients with HD and mediastinal involvement were retrospectively investigated with ⁶⁷Ga scintigraphy 72 h after injection of 220 MBq ⁶⁷Ga citrate (planar and single-photon emission tomographic studies) following the completion of chemotherapy. At the same time, they all underwent computed tomography (CT). Patients were followed up for an average of 63 months (range 28-124 months). The disease status was newly diagnosed disease in 64 of the patients and relapse in 10. Systemic symptoms were absent (A) in 34 cases and present (B) in 40 cases. Forty-one patients had stage I or II disease and 33 patients had stage III or IV disease. Twenty-two patients had bulky disease on initial diagnosis. At the end of chemotherapy, all 74 patients showed regression of the mass by more than 50% (50%-100%) on CT. Patients were divided into two groups according to the positivity or negativity of the gallium scan after chemotherapy: 61 patients had negative and 13 patients had positive gallium scans. In the gallium-negative group, 19.7% of the patients relapsed and 91.8% were alive at the end of the follow-up. Relapse occurred in 20% of the patients with residual mass and in 19.6% of the patients without residual mass. In the gallium-positive group, 84.6% of the patients had recurrent disease and 61.5% were alive after intensive chemotherapy. There was a statistically significant difference in overall survival between patients with positive and patients with negative gallium results (P=0.0034). Disease-free survival differed significantly between patients with positive and patients with negative gallium scans at the end of chemotherapy (P<0.0001). The relative risk of death was 5.2 and the relative risk of relapse was 11.3 for patients with positive gallium scans, in comparison to those with negative gallium scans. The positive and negative predictive values for predicting relapse were 85% and 87%, respectively. It is concluded that even if gallium scan is performed at the end of chemotherapy, it can predict outcome. Alternative therapy may be required on the basis of gallium scan results obtained after treatment.     

Hodgkin disease: prediction of outcome with 67Ga scintigraphy after one cycle of chemotherapy

PURPOSE: To investigate gallium 67 scintigraphy performed early during treatment as a means to predict outcome and thus to optimize treatment of Hodgkin disease (HD) in the future. MATERIALS AND METHODS: Ninety-eight patients with HD were examined. Thirty-one patients underwent 67Ga scintigraphy after one chemotherapy cycle and 83 patients after a mean 3.5 cycles (range, 2-5 cycles). Sixteen patients underwent 67Ga scintigraphy both after one cycle and at midtreatment. Patients underwent whole-body scintigraphy and single photon emission computed tomography of the torso. Torso computed tomography (CT) was performed after a mean 3.5 cycles (range, 2-6 cycles). Failure-free survival was compared between patients with positive and patients with negative test findings (Kaplan-Meier method), and the significance of the difference was calculated. The association of failure-free survival with various prognostic clinical factors before treatment was compared (log-rank test univariate analysis). RESULTS: Failure-free survival differed significantly (P < .002) between patients with positive and patients with negative 67Ga scintigrams after one chemotherapy cycle but not at midtreatment. Failure-free survival was not significantly different between patients with positive and patients with negative CT scans at midtreatment. Twenty-two (92%) of 24 patients with negative 67Ga scintigrams after one cycle and 64 (82%) of 78 patients with negative scintigrams at midtreatment remained in complete response. In four (57%) of seven patients with positive 67Ga scintigrams after one cycle, treatment failed. CONCLUSION: 67Ga scintigraphy after one cycle of chemotherapy is a good early predictor of outcome of HD.     

Aggressive non-Hodgkin lymphoma: early prediction of outcome with 67Ga scintigraphy

PURPOSE: To evaluate use of gallium 67 scintigraphy early during chemotherapy to predict the outcome in patients with aggressive non-Hodgkin lymphoma. MATERIALS AND METHODS: Among 118 patients, 67Ga scintigraphy was performed after one cycle of chemotherapy in 51 patients, after a median of 3.5 cycles in 97 patients, and both in 30 patients. Computed tomography (CT) was performed after a median of 3.5 cycles of treatment in 87 patients. The failure-free survival was compared between patients with positive or negative 67Ga or CT scans by using the log-rank test. Multivariate analysis helped determine the relation between 67Ga scintigraphic and CT findings and the outcome. RESULTS: The differences in failure-free survival between patients with positive versus negative 67Ga scans after one cycle of treatment (P < .001) and at midtreatment (P < .001) were significant. There was no statistically significant difference in failure-free survival between patients with positive versus negative CT findings during treatment. In multivariate analysis, 67Ga scintigraphy after one cycle (P < .045) and at midtreatment (P < .006) was an independent factor associated with outcome. CONCLUSION: Gallium 67 scintigraphic findings after one cycle of chemotherapy and at midtreatment are predictive of outcome in patients with aggressive non-Hodgkin lymphoma. CT findings are not predictive. Early 67Ga scintigraphy during chemotherapy is a good indicator of patients who may benefit from a change to a more aggressive treatment. A future study is necessary to investigate the potential effect of early change of treatment.     

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 (≥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. Received 5 July and in revised form 9 September 1999     

A case of orbital MALT lymphoma in which 67Ga scintigraphy was useful for evaluating the radiation therapy response

A 67-year-old man was hospitalized at our institution complaining with epiphora and exophthalmos on the left side. Magnetic resonance imaging (MRI) showed an ill demarcated retrobulbar mass in the left orbit. 67Ga scintigraphy revealed avid uptake in the left orbital region. The patient was treated with radiation therapy. One month after the radiation therapy, the size of the mass decreased remarkably on MRI. 67Ga planar imaging after treatment showed no uptake, but 67Ga SPECT showed slightly increased uptake in the left orbital region. One year after the radiation therapy, MRI showed residual mass in the left orbital region. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. 1.8 years after the radiation therapy, MRI showed the residual mass with no interval change in size. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. The patient remains well with no evidence of local recurrence. 67Ga scintigraphy is useful in assessing the response to radiation therapy of MALT lymphoma in this case.     

Accumulation of gallium-67 within mature and immature teratoma in pediatric patients: investigation for the uptake mechanism

OBJECTIVE: We encountered cases of mature and immature teratoma with positive uptake of (67)Ga. The objective of this study is to investigate the mechanism of (67)Ga accumulation within mature and immature teratomas by comparing the findings of gallium scan, computed tomography (CT), and autoradiography of surgical specimens with the pathological findings. METHODS: The subjects comprised 14 children who underwent surgical resection for intra-abdominal mature and immature teratomas, which were histologically proved to be of the mature and immature subtype. Their age ranged from 24 days to 14 years. The origins of the mature teratomas consisted of seven ovaries including one bilateral case, two retroperitoneal, and two sacrococcygeal regions. The origins of the immature teratomas were retroperitoneum in two cases, an ovary and a sacrococcygeal region. Complete surgical excision was feasible in all children. They underwent both gallium scan and CT prior to surgery. Single-photon emission computed tomography was added in some cases. For two gallium-positive cases, radiography and scintigraphy (autoradiography) of the resected specimen were performed. RESULTS: Of the 14 children, 5 (one with immature and four with mature subtype) showed positive (67)Ga uptake within tumors, which originated from the retroperitoneum in the 3 boys, and from the ovary in the 2 girls. All had typical CT findings of teratoma, including calcifications, fat components, cystic areas, and solid parts. (67)Ga accumulation in the four mature teratomas appeared discretely strong, and was considered to correspond with intralesional calcifications. However, in the remaining one immature teratoma, the gallium distribution was diffuse within the tumor. The comparison between radiography and autoradiography of the resected mature teratomas confirmed the correlation between the intralesional calcifications and areas of (67)Ga accumulation. CONCLUSIONS: A high-uptake ratio of (67)Ga in benign teratoma was indicated. A close correlation between gallium scan and CT helps to ascertain whether (67)Ga uptake results from malignant and/or immature elements, or mature tissue components.     

Thallium-201 scintigraphy in bone sarcoma: comparison with gallium-67 and technetium-MDP in the evaluation of chemotherapeutic response

This study attempts to characterize thallium-201 (201TI) uptake in patients with bone and soft-tissue sarcoma and to compare these findings with gallium-67 (67Ga) and bone scintigraphy with emphasis on evaluating tumor viability before and after chemotherapy. Thirty-eight patients with surgically-proven sarcomas were evaluated. All patients had gallium and thallium studies. Nineteen patients underwent pre- and post-chemotherapy thallium and evaluation. Seven patients also had technetium-99m-MDP (99mTc-MDP) bone scintigraphy comparisons. Pathologic changes pre- and postchemotherapy were graded on the basis of %tumor necrosis as defined histologically. Scintigraphic comparisons demonstrated a high degree of correlation with 201TI and poor correlation with 99mTc-MDP. Thallium-201 was superior to 99mTc-MDP and 67Ga in predicting tumor response to chemotherapy as determined by %tumor necrosis determined histologically. Gallium was superior to Tc-MDP in predicting response to chemotherapy. However, both 67Ga and 99mTc-MDP appear to be affected by factors other than tumor activity.     

Noninvasive staging of lung cancer. Indications and limitations of gallium-67 citrate imaging

The results of evaluation of the hila and mediastinum with 67Ga scans are contradictory, as are the recommendations by different investigators on the use of 67Ga scintigraphy in the clinical evaluation of patients with primary lung carcinoma. Nevertheless, the economy and logistic simplicity of evaluating local and distant metastases with a single imaging procedure are attractive, especially because the symptoms may not enable the physician to make a correct identification of the organ systems affected by metastases. Neumann and Hoffer state that "at present conventional Ga-67 scanning techniques cannot be recommended for preoperative staging of mediastinal lymph node metastases in lung cancer patients." According to Waxman, 67Ga scintigraphy, relative to other imaging modalities, is a sensitive indicator of hilar spread of a tumor. However, because of the normally high background activity within the sternum and spine, mediastinal abnormalities may be poorly detected. Since most pulmonary tumors metastasize via regional nodes to the pulmonary hilum and then to the mediastinum, the high sensitivity for the detection of pulmonary hilar abnormalities and the high specificity for detection of mediastinal lesions suggest that gallium scintigraphy is a valuable adjunctive test when used appropriately. The results obtained locally are probably the best guide for individual physicians in the selection of diagnostic tests for their patients. Gallium scans may thus be helpful in the clinical evaluation of patients with lung cancer. Although gallium scans identify mediastinal node involvement, there is considerable controversy over the relationship between the sensitivity and specificity of the method. By detecting distant extrathoracic metastases, the 67Ga scan may identify a small group of patients who can be spared a needless operation. Gallium scanning fails specifically for metastases within the brain; thus, it does not supplant CT scans of the brain and it is less sensitive than bone scans in detecting osseous metastases. Gallium scanning of patients with small-cell lung cancer is not useful in the selection of therapy but does become important from a prognostic standpoint. Patients with extrathoracic involvement by small-cell carcinoma of the lung are known to have limited survival times compared with those of patients with thoracic involvement alone. In identifying patients with extensive disease, the oncologist is thus provided with prognostic information that may be useful in the counseling of the patient and the patient's family.     

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.     

Hodgkin's disease. Prognostic value of Gallium-67 scintigraphy.

AIM: The aim of this study is to assess the clinical impact of gallium-67 scintigraphy, before and after treatment, in patients with Hodgkin's disease, and to compare the overall survival between the patients whose gallium studies after treatment were negative and those whose studies remained positive. METHODS: We have studied 75 patients (40 women, 35 men) with Hodgkin's disease. All the patients underwent (67)Ga scintigraphy at the moment of the diagnosis (basal study) and in the case that basal study was positive (abnormal hyper-uptake focus) we performed follow-up studies after the treatment. We have calculated the overall survival among patients whose studies after treatment were negative (1(st) group) and those whose studies remained positive (2(nd) group) and between patients whose studies were negative at diagnosis (3(rd) group). RESULTS: Gallium scintigraphy was positive at diagnosis in 47 patients (62.6%). In 39 of them we were able to perform the follow-up study after treatment. The follow-up study was negative in 31 patients while in 8 patients the gallium scintigraphy remained positive. The overall survival was significantly higher (p<0.001) in the 1(st) group compared with the 2(nd) group. The overall survival was higher in the 1(st) group compared with the 3(rd) but statistic significance level was not reached. CONCLUSION: Our data suggest that: 1) in Hodgkin's disease (67)Ga scintigraphy is useful to establish the diagnosis of complete remission; 2) if the gallium scan remains positive after treatment, the prognosis of patients is worse than the prognosis of patients with a negative scan.     

Somatostatin receptor scintigraphy and gallium scintigraphy in patients with sarcoidosis.

Somatostatin receptor scintigraphy (SRS) has been shown to reveal sarcoidosis sites. The aim of this study was to prospectively compare SRS and gallium scintigraphy in the evaluation of pulmonary and extrapulmonary involvement in patients with proven sarcoidosis. METHODS: Eighteen patients with biopsy-proven sarcoidosis were included. Nine were or recently had been receiving steroid therapy at the time of the examination. Planar gallium scintigraphy (head, chest, abdomen, and pelvis) and thoracic SPECT were performed at 48-72 h after injection of a mean dose of 138 +/- 21 MBq 67Ga. Planar SRS and thoracic SPECT were performed at 4 and 24 h after injection of a mean dose of 148 +/- 17 MBq 111n-pentetreotide. RESULTS: Gallium scintigraphy found abnormalities in 16 of 18 patients (89%) and detected 64 of 99 clinically involved sites (65%). SRS found abnormalities in 18 of 18 patients and detected 82 of 99 clinically involved sites (83%). Of the 9 treated patients, gallium scintigraphy found abnormalities in 7 (78%), detecting 23 of 39 clinically involved sites (59%), whereas SRS found abnormalities in 9, detecting 32 of 39 clinically involved sites (82%). CONCLUSION: This study suggests that, compared with gallium scintigraphy, SRS appears to be accurate and contributes to a better evaluation of organ involvement in sarcoidosis patients, especially those treated with corticosteroids.     

Residual mass and negative gallium scintigraphy in treated lymphoma

Two patients with treated lymphoma demonstrated a residual mass on CT following treatment. In both cases gallium-67 (67Ga) scintigraphy demonstrated increased uptake in the original tumor mass and no uptake in the mass after treatment. In both cases the entire residual tumor mass was resected and found to contain no cancer tissue. This is further evidence of the role 67Ga scintigraphy may play in monitoring response of lymphoma patients to treatment. In contrast, other imaging modalities such as ultrasound, plain film x-rays, or CT only show the presence of a mass but not its nature.     

Comparison of technetium-99m methoxyisobutylisonitrile and gallium-67 citrate scanning in the assessment of lymphomas

The aim of this study was to compare the value of scintigraphy using technetium-99m methoxy-isobutylisonitrile (MIBI) with that of scintigraphy using gallium-67 citrate in the assessment of Hodgkin's disease and non-Hodgkin's lymphoma and to relate these results with those of CT scan and MRI. Fifty-eight patients were included either for a follow-up examination or for monitoring of their treatment. Twenty-three residual masses were studied. A whole-body scan was performed, followed by single-photon emission computed tomography (SPET) 20 min after injection of 740 MBq of^99mTc-MIBI and 72 h after injection of 185 MBq of⁶⁷Ga citrate. The overall sensitivity of^99mTc-MIBI and⁶⁷Ga citrate was 71% and 68%, respectively, and the overall specificity was 76% and 44%, respectively. For residual masses, the sensitivity was 44% with both tracers and the specificity was 80% with^99mTc-MIBI and 53% with⁶⁷Ga citrate. The positive predictive values were 85% and 68% and the negative predictive values were 59% and 44%, respectively. The signal-to-background ratio was 1.5 for^99mTc-MIBI and 2 for⁶⁷Ga citrate. At present,^99mTc-MIBI cannot replace⁶⁷Ga citrate in the assessment of lymphomas.     

Bone lymphoma: 67Ga scintigraphy and CT for prediction of outcome after treatment.

The purpose of the present study was to evaluate the role of 67Ga scintigraphy and CT in treatment monitoring of bone lymphoma. METHODS: Forty-four lymphoma patients with 91 sites of bone involvement were evaluated. Eight patients had Hodgkin's disease, and 36 patients had non-Hodgkin's lymphoma. Thirteen patients had primary lymphoma of the bone, and 31 patients had secondary lymphoma of the skeleton. 67Ga and CT studies were performed at baseline, during and at the end of treatment, and during follow-up. Positive 67Ga studies showed abnormal uptake in sites of lymphomatous involvement. Positive CT studies showed lesions with patterns of osteolysis, patterns of osteosclerosis, or a mixed pattern. A negative 67Ga or CT study showed disappearance of all lymphoma-related abnormalities. The sensitivity and specificity of 67Ga scintigraphy at presentation were calculated. Patterns of bone lymphoma on CT and their treatment-related changes were analyzed and recorded. Freedom-from-progression (FFP) curves were used to determine the prognostic value of positive and negative 67Ga and CT findings for predicting outcome after treatment. RESULTS: The sensitivity of 67Ga for diagnosis of bone lymphoma was 93%, and the specificity was 91%. A CT pattern of osteolysis was seen in 70% of skeletal disease sites at diagnosis and in 21% during follow-up. Osteosclerosis was present in 23% of sites at diagnosis and in 38% during follow-up. 67Ga findings became negative in 25% of patients during treatment, whereas only 1 patient showed negative CT findings. Forty-two percent of patients had negative 67Ga findings at the end of treatment, compared with 18% who had negative CT findings. Sixty-one percent of patients had negative 67Ga findings during follow-up, compared with 21% who had negative CT findings. A statistically significant difference in FFP was found between patients with positive and negative 67Ga findings at all evaluated time points. No statistically significant difference in FFP was found at any time point between patients with positive and negative CT findings. CONCLUSION: 67Ga scintigraphy has a high sensitivity and specificity for diagnosis of bone lymphoma. Bone lymphoma may show osteosclerotic and osteolytic CT patterns at diagnosis, during treatment, and after treatment. In most patients, CT studies do not become negative even 1 y after treatment. 67Ga scintigraphy, however, may be used as a predictor of long-term outcome in patients with lymphoma of the skeleton.