Detection of occult bone metastases of lung cancer with fluorine-18 fluorodeoxyglucose positron emission tomography

Accurate staging of cancer has a critical role in optimal patient management. Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) is superior to CT in the detection of local and distant metastases in patients with non-small cell lung cancer. Although Tc-99 m methylene diphosphonate (MDP) bone scanning is well established in the evaluation of bone metastases, there are conflicting reports on the use of FDG PET in the evaluation of skeletal metastases. We report on a patient with locally advanced lung carcinoma in whom FDG PET accurately identified previously unsuspected widespread asymptomatic bone metastases (bone scan and X-rays negative, confirmed on MRI). Assessment of glucose metabolism with FDG PET might represent a more powerful tool to detect bone metastases in lung cancer compared with conventional bone scans.     

F-18 fluorodeoxyglucose positron-emission tomography in the diagnosis of tumor recurrence and metastases in the follow-up of patients with breast carcinoma: a comparison to conventional imaging

AIM: To evaluate the role of F-18-fluorodeoxyglucose positron-emission tomography (F-18 FDG PET) in the follow-up of breast carcinoma in case of clinical suspicion of local recurrence or distant metastases and/or tumor marker increase in correlation to conventional imaging. MATERIAL AND METHODS: Retrospective analysis of the results of F-18 FDG PET (ECAT ART(R), Siemens CTI MS) of 62 patients (age 58.5 +/- 12.8) with surgically resected breast carcinoma (time interval after surgery, 86 +/- 82 months, mean follow-up 24 +/- 12.6 months). Patient- and lesion-based comparison with conventional imaging (CI) including mammography (MG), ultrasonography (US), computerized tomography (CT), magnetic resonance imaging (MRI), radiography (XR) and bone scintigraphy (BS). Furthermore, we evaluated the influence on tumor stage and therapeutic strategy. A visual qualitative evaluation of lesions was performed. RESULTS: On a patient base, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for detecting local recurrence or distant metastases were calculated to be 97%, 82%, 87%, 96% and 90% compared with 84%, 60%, 73%, 75% and 74% with CI. On a lesion base, significantly more lymph node (84 vs. 23, P < 0.05) and fewer bone metastases (61 vs. 97, P < 0.05) could be detected by using F-18 FDG PET compared with CI. Sclerotic bone lesions were predominantly detected by BS. On the other hand, there were several patients with more FDG positive bone lesions and also mixed FDG positive/Tc-99m methylenediphosphonate (MDP) negative and FDG negative/Tc-99m MDP positive metastases. In case of normal tumor markers, sensitivity, specificity, PPV, NPV and accuracy for detecting local recurrence or distant metastases were calculated to be 100%, 85.0%, 78.6%, 100% and 90.3% for FDG PET and 80%, 50%, 50%, 80% and 61.5% for CI. An upstaging could be observed in 9.7% (6/62) and downstaging in 12.9% (8/62), leading to a change in therapeutic regimen in 13 patients (21%). CONCLUSIONS: F-18 FDG PET demonstrates apparent advantages in the diagnosis of metastases in patients with breast carcinoma, compared with conventional imaging on a patient base. On a lesion base, significantly more lymph node and less bone metastases can be detected by using F-18 FDG PET compared with conventional imaging, including bone scintigraphy. In patients with clinical suspicion but negative tumor marker profile, too, F-18 FDG PET seems to be a reliable imaging tool for detection of tumor recurrence or metastases. Considering the high predictive value of F-18 FDG PET, tumor stage and therapeutic strategy will be reconsidered in several patients.     

Tc-99m(V) DMSA imaging. A new approach to studying metastases from breast carcinoma.

Combined Tc-99m MDP skeletal imaging and Tc-99m(V) DMSA whole body scans to detect metastases were performed during the follow-up of 30 patients who underwent surgery for breast carcinoma. Eight patients had normal Tc-99m MDP and Tc-99m(V) DMSA scans and were declared free of metastatic disease, further confirmed by no change in symptomatology over a 1-year follow-up period. Twenty-two patients had positive Tc-99m MDP scans with varied skeletal involvement. Tc-99m(V) DMSA scans showed matched areas of increased radiotracer concentration in bony metastases in 20 of these patients. Tc-99m(V) DMSA concentration was not seen in traumatic vertebral collapse or in coexistent osteoarthritic disease in vertebral metastatic involvement. Interestingly, Tc-99m(V) DMSA showed increased concentration in brain and liver metastases. Pentavalent Tc-99m(V) DMSA appears useful for detecting skeletal and soft-tissue metastases in breast carcinoma, and can improve the specificity of Tc-99m MDP bone scans in screening for bone metastases.     

18 F-FDG PET显像与99Tcm-MDP全身骨显像诊断肿瘤远处转移的比较

目的　评价18F 脱氧葡萄糖 (FDG)PET肿瘤显像与99Tcm 亚甲基二膦酸盐 (MDP)全身骨显像对检出骨和远处转移的价值。方法　对 16例恶性肿瘤放化疗后的患者进行18F FDGPET显像和99Tcm MDP全身骨显像 ,并对两种结果进行了比较。结果　 16例肿瘤患者中18F FDGPET显像皆阳性 ,其中 14例患者有远处转移 ,转移病灶共 62处 ,其中骨转移病灶 2 0处 ;在全身骨显像中 ,11例有局限性异常放射性浓聚 ,其中 2例为单一病灶 ,9例为多发病灶 ,共检出病灶 5 7处 ,另 5例骨显像正常。结论　18F FDGPET对恶性肿瘤的诊断具有较高的准确性和特异性 ,但对骨转移灶的诊断价值相对较差 ;99Tcm MDP显像阴性或单一病灶的可疑转移瘤患者有必要进行18F FDGPET检查 ,以明确诊断其他远处转移灶     

Mismatch of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and Tc-99m pertechnetate single photon emission computed tomography (SPECT) in a euthyroid multinodular goiter

Imaging results of F-18 fluorodeoxyglucose (FDG) PET/CT scanning and Tc-99m pertechnetate scintigraphy of the thyroid gland are described and compared with pathology in a patient who was followed after left nephrectomy for renal cell carcinoma diagnosed 10 years earlier. On F-18 FDG PET/CT scanning, a multinodular struma with increased localized F-18 FDG uptake in 4 nodules was seen. Two nodules with increased glucose metabolism appeared normal on Tc-99m pertechnetate scintigraphy. Pathology indicated hyperplastic nodules. High focal F-18 FDG uptake was also seen in a lesion that corresponded with a "cold" nodule on Tc-99m pertechnetate scintigraphy, suggesting malignant disease. However, pathology revealed hyperplastic nodules with a background of aspecific lymphocytic thyroiditis. A fourth nodule with increased F-18 FDG uptake appeared mixed ("cold"/"hot") on Tc-99m pertechnetate scintigraphy. On pathology, a well-differentiated follicular carcinoma was found. These findings, in a single patient, illustrate the wide spectrum of matched and mismatched F-18 FDG and Tc-99m pertechnetate thyroid uptake along with their variable pathologic correlates.     

Pathologic fractures in a patient with renal osteodystrophy. Failure of early detection on bone scans

A case of false-negative Tc-99m MDP bone scintigrams, taken at one and two weeks for pathologic fractures in a patient with metabolic bone disease and a super-scan appearance, is described. The patient had renal osteodystrophy, and postparathyroidectomy hypocalcemia. Postoperative seizures caused multiple pathologic fractures. Initial scans were negative for focal tracer localization in the presence of a continued super-scan appearance. After months of calcium and vitamin D replacement therapy, fracture sites became positive on Tc-99m MDP imaging. The observations in this case lend credence to the hypothesis of Tc-99m MDP binding by immature collagen in the production of a super scan in metabolic bone disease, as well as that of Tc-99m MDP chemisorption to calcium hydroxyapatite crystal in fracture healing. In addition, aluminum toxicity, common in chronic renal osteodystrophy, may have played a role in the delayed fracture healing.     

Imaging of malignant lymphomas with F-18 FDG coincidence detection positron emission tomography

PURPOSE: The authors evaluated the utility of F-18 fluorodeoxyglucose (FDG) coincidence detection (CoDe) positron emission tomography (PET) for staging, post-treatment evaluation, and follow-up assessment of patients with malignant lymphomas. MATERIALS AND METHODS: Fifty-eight patients with histologically proved malignant lymphomas (4 Hodgkin's disease, 54 non-Hodgkin's lymphoma) underwent CoDe PET using F-18 FDG. CoDe PET was performed using a dual-head gamma camera equipped with coincidence detection circuitry. Of the 87 CoDe PET studies, 26 were performed for staging, 38 for post-treatment evaluation, and 23 for follow-up evaluation of recurrence. The entire trunk, from the cervical to the inguinal regions, or selected regions were scanned with the patient in the supine position. No attenuation correction was made and reconstruction was performed using filtered back-projection rather than iterative reconstruction. CoDe PET findings were compared with corresponding results of computed tomographic (CT) and magnetic resonance imaging (MRI), tissue biopsy, or clinical follow-up. RESULTS: For staging, 52 sites were positive on CoDe PET or CT-MRI. CoDe PET detected 49 sites (94%), and CT-MRI showed 47 sites (90%). CoDe PET detected five more lymphomatous lesions and missed three lesions. For post-treatment evaluation, CoDe PET showed a positive predictive value of 100% and a negative predictive value of 83%, but the validated cases numbered only 11. For follow-up for recurrence, CoDe PET had a negative predictive value of 90%, but frequent false-positive findings were noted in the head and neck region as a result of underlying inflammatory changes. CONCLUSIONS: For staging, FDG CoDe PET alone without attenuation correction is not sensitive enough to be used as an independent imaging method, especially for small abdominal lesions. However, it appears to be an accurate method for assessing residual disease and for patient follow-up.     

Early detection of bone marrow involvement in extramedullary plasmacytoma by whole-body F-18 FDG positron emission tomography

The utility of positron emission tomography (PET) with the glucose analog 2-deoxy-2-[F-18] fluoro-D-glucose (F-18 FDG) in plasmacytoma has not been well evaluated. The authors report a case of extramedullary plasmacytoma (EMP) in which whole-body F-18 FDG PET was useful in the early detection of bone marrow involvement. A 34-year-old woman had EMP without histologic or radiologic evidence of bone lesions. However, the early phase of bone marrow involvement was considered because of spotty accumulation shown by F-18 FDG PET. A follow-up F-18 FDG PET study after radiotherapy showed intense multifocal accumulation in the bone marrow, which was confirmed on bone marrow aspiration as abnormal proliferation of plasma cells. Whole-body F-18 FDG PET has the potential to detect the early phase of bone marrow involvement in patients with EMP.     

Detection of multiple myeloma by PET/CT in a patient with colon cancer

A 76-year-old man with previous sigmoid colon resection for adenocarcinoma had low back pain for 2 months. Whole-body bone scintigraphy showed multiple focal Tc-99m methylene diphosphonate (MDP)-avid lesions in both rib cages and 3 lumbar vertebrae, indicating metastases. F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) imaging was performed for further evaluation of this possible metastatic disease and demonstrated the lumbar and costal metastases and several hypermetabolic areas in the pelvic bones, multiple thoracic vertebrae, both shoulders, and the right femur. Histopathologic examination of the right-sided iliac crest, however, revealed multiple myeloma.     

Anterior choroidal artery infarction presenting as a progressive cognitive deficit

PURPOSE: The authors describe a patient in whom neuroimaging using Tc-99m HMPAO SPECT, F-18 fluorodeoxyglucose (F-18 FDG) coincidence imaging, and magnetic resonance imaging (MRI) identified an anterior choroidal artery infarction. Neuroimaging played a critical role in confirming this diagnosis, because the patient had symptoms of progressive cognitive decline and satisfied the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for Alzheimer's disease (AD). METHODS: Tc-99m HMPAO brain SPECT was performed using a triple-head gamma camera. F-18 FDG scanning was obtained 40 minutes after intravenous injection of 5 mCi F-18 FDG using a coincidence camera. A brain MRI scan was performed using a 1.5-Tesla scanner. RESULTS: Tc-99m HMPAO SPECT showed focal hypoperfusion to the right parahippocampal cortex. F-18 FDG coincidence imaging showed a more extensive reduction in glucose metabolism compared with SPECT. The MRI scan confirmed the presence of a small segmental choroidal artery infarction. The Tc-99m HMPAO and F-18 FDG scans were not consistent with AD. CONCLUSIONS: This case illustrates the value of the regional cerebral blood flow SPECT for evaluating memory impairment in the elderly. Decreased regional cerebral blood flow to the posterior temporoparietal region is consistent with AD, whereas regional cerebral blood flow diminution in a vascular territory is consistent with vascular dementia. In this case, the patient was clinically diagnosed with AD, and SPECT was performed to establish the baseline regional cerebral blood flow before the cholinesterase inhibitor donepezil was administered. An infarction was diagnosed on the regional cerebral blood flow brain SPECT scan, which was later confirmed by MRI. Infarctions of the parahippocampal cortex may resuft in memory impairment, which can appear clinically similar to AD.     

Role of F-18 FDG PET/CT in assessing bone marrow involvement in pediatric Hodgkin’s lymphoma

Objectives

The aim of the current study was to assess the utility of F-18-fluoro-2-deoxy-d-glucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) in assessing bone marrow involvement (BMI) compared to bone marrow biopsy (BMB) in initial staging of Hodgkin’s lymphoma (HL) in pediatric patients.

Methods

Data of 38 pediatric patients (mean age 9.8 years, range 3–18 years) with HL were analyzed for the involvement of bone marrow. All patients underwent non-contrast F-18 FDG PET/CT study. BMB was done in 31 patients from the bilateral iliac crests. Scans were interpreted by two nuclear medicine physicians blinded to the details of BMB.

Results

Of the 31 patients who underwent BMB, 5 patients had lymphomatous involvement on BMB. PET/CT was positive in four of these five patients. In 26 patients negative on BMB, PET was negative in 23 patients and positive in 3 patients for BMI. The sensitivity and negative predictive value of F-18 FDG PET/CT was 87.5 and 96 %, respectively, for BMI.

Conclusions

F-18 FDG PET/CT can predict BMB results with high accuracy. F-18 FDG PET/CT may be used at initial staging of pediatric Hodgkin’s lymphoma as it uncovers unsuspected BMI and BMB may be omitted in patients with PET-positive BMI.     

Increased accumulation of Tl-201 in monostotic Paget's disease of the patella: evaluation with quantitative analysis.

Monostotic Paget's disease of the patella was detected with Tc-99m MDP and Tl-201 scans. Diffuse intense uptake of MDP in the left patella was observed on the blood-pool and late phases of the bone scan. Tl-201 imaging was performed to differentiate a malignant process and showed diffuse marked accumulation at the same site. Semiquantitative analysis of the patella region on both Tc-99m MDP and Tl-201 scans did not support a diagnosis of cancer. Radiographs showed the features of Paget's disease of the bone. Findings of a pathologic evaluation were compatible with the diagnosis of osteitis deformans. This case represents the unusual skeletal involvement of monostotic Paget's disease of the bone in the patella. Tl-201 accumulation in the Paget's lesion was suggested to be caused by increased metabolic activity of the lesion but was not indicative of a malignant process.     

Osteoblastoma in the nasal cavity: F-18 FDG PET/CT and Tc-99m MDP 3-phase bone scan findings with pathologic correlation

A benign osteoblastoma of the nasal cavity is very rare. A 57-year-old woman, who had a radical hysterectomy for carcinoma of the uterine cervix 5 years ago, underwent F-18 FDG PET/CT. An expansile bone tumor with high glucose metabolism in the middle turbinate of the left nasal cavity was incidentally demonstrated. A subsequent Tc-99m methylene diphosphonate 3-phase bone scan revealed focal increased uptake of radionuclide in all 3 phases at the corresponding tumor. Histology confirmed a benign osteoblastoma that was composed of proliferating osteoblasts with woven bone spicules and rich vascular stroma. Scintigraphic findings, including F-18 FDG PET/CT and 3-phase bone scan, reflected the pathologic features well.     

Increased bone marrow blood flow in sickle cell anemia demonstrated by thallium-201 and Tc-99m human albumin microspheres

Lower extremity vascularity in nine patients with sickle cell anemia was studied by intra-arterial Tc-99m human albumin microspheres or intravenous thallium 201. In eight patients, the normal pattern of greater muscle than bone activity was reversed with marked tracer localization in skeletal parts usually not visualized. In four cases, there were distinct focal abnormalities in the femurs and tibias which correlated with defects on Tc-99m sulfur colloid marrow scans. Tc-99m pyrophosphate bone scans demonstrated normal uptake in the same areas. The scintigraphic findings indicate a markedly increased relative bone marrow blood flow.     

Fluorine-18 fluorodeoxyglucose imaging using dual-head coincidence positron emission tomography without attenuation correction in patients with head and neck cancer.

PURPOSE: An accurate, preoperative assessment of tumor extent and lymph node involvement is necessary to plan and tailor therapy for patients with head and neck cancer. Metabolic imaging with fluorine-18 fluorodeoxy-glucose (FDG) is a good method to detect primary tumors in the head and neck and to assess the involvement of lymph nodes, but it is not widely available because of the high cost of positron emission tomography (PET). Recently, an alternative method for using FDG was developed: coincidence detection PET (CoDe PET) using a gamma camera. The aim of this study was to evaluate the clinical utility of FDG CoDe PET using a gamma camera in patients with head and neck cancer. MATERIALS AND METHODS: Thirty FDG CoDe PET studies without attenuation correction were performed in seven patients before therapy and in 19 patients after therapy (ages: 25-79 years, mean, 50 +/- 13 years; 18 men, 8 women) with various head and neck cancers. All patients had fasted for 6 to 12 hours and were injected with 111 to 370 MBq F-18 FDG 1 hour before imaging. Visually detectable focal FDG uptake in the primary tumor site or in the neck was considered positive except for physiologic uptake. The FDG CoDe PET studies were correlated with MRI. The gold standard for the presence of disease was the combination of repeated MRIs, endoscopic examination, and 3 months of follow-up clinical evaluation. RESULTS: FDG CoDe PET had a detection rate that was comparable to that of MRI in the pretherapy group. However, in the posttherapy group, FDG CoDe PET could differentiate residual tumor or tumor recurrence from radiation change more accurately than could MRI. However, it had a less accurate detection rate for cervical node metastases because of asymmetric neck muscle uptake. CONCLUSIONS: FDG CoDe PET is a sensitive and cost-effective method to detect primary tumor and lymph node involvement in primary head and neck cancers. It is also useful in differentiating residual tumor or tumor recurrence from posttherapy changes in patients with head and neck tumors.     

Breast cancer imaging with PET and SPECT agents: an in vivo comparison

Several radiopharmaceuticals and imaging techniques are proposed for breast cancer imaging. Since limited data are available of the uptake of SPECT and PET radiopharmaceuticals in malignant breast tumors and their metastases the aim of this study was to compare the uptake values and to correlate these data with imaging findings. Methods: We have studied the uptake of F-18 FDG, Tc-99m MIBI and Tc-99m (V)DMSA in 31 tumors using immunosuppressed rats implanted with HH-16 clone 4 mammary tumor cells. Tumor gamma camera and PET imaging was performed to gain biokinetic data and uptake values by ROI-analysis. Results: Tumor uptake was highest for F-18 FDG > Tc-99m (V)DMSA > Tc-99m MIBI. The uptake ratios (tumor to muscle) correlated well with the ratios calculated by ROI-analysis determined by imaging. Conclusions: In this in-vivo model, F-18 FDG revealed the best uptake and imaging properties and may be the radiopharmaceutical of choice for routine breast cancer imaging.     

The clinical usefulness of F-18 FDG coincidence PET without attenuation correction and without whole-body scanning mode in pulmonary lesions comparison with CT, MRI, and clinical findings

PURPOSE: This study was undertaken to assess the clinical usefulness of fluorine-18 flurodeoxyglucose (F-18 FDG) coincidence detection (CoDe) positron emission tomography (PET) of various lung lesions by comparing it with CT, MRI, and clinical findings. MATERIALS AND METHODS: Forty-two patients with pulmonary lesions underwent CoDe PET using a dual-head gamma camera equipped with a 5/8 inch thick NaI (Tl) crystals. The patients were prepared for the study by overnight fasting. Data was acquired at approximately 1 hour after the intravenous injection of 111 to 370 MBq (3 to 10 mCi) of F-18 FDG. A spinal scan of the thorax was performed using a slip ring gantry for 30 minutes. After rebinning, routine tomographic slices were reconstructed without attenuation correction and the images were analyzed visually. RESULTS: Pathologic diagnoses and staging were obtained at surgery in nine patients; in the remaining 33 patients, aspiration cytology was available. CoDe PET detected all 35 pathologically proved malignant lesions. In nine patients who underwent surgery, seven CoDe PET studies corresponded with pathologic staging, whereas in six of the nine patients, CT and MRI corresponded with the pathologic findings. Seven patients also had benign lesions that showed FDG uptake. CONCLUSIONS: F-18 FDG CoDe PET was sensitive in the evaluation of lung lesions but was not specific for malignancy. F-18 FDG CoDe PET was more sensitive than CT and MRI in nodal staging in the limited number of patients studied thus far.     

Testicular lymphoma with bone/bone marrow metastases illustrated by scrotal sonography, spinal MRI, and total body Tc-99m HMDP and Tc-99m MIBI imagines

An 83-year-old man with testicular lymphoma demonstrated progressive scrotal enlargement with non-homogeneity sonographically and abnormally increased uptake in the scrotum of Tc-99m HMDP and Tc-99m MIBI scintigraphically. Extensive bone/bone marrow metastases were exhibited by Tc-99m MIBI and Tc-99m HMDP scintigraphies and MRI of the spine. In addition, focal/tubular activity of the femoral bone marrow on Tc-99m MIBI imaging was consistent with skeletal scintigraphic findings. It is emphasized that Tc-99m MIBI total body imaging enabled the demonstration of testicular lymphoma as increased uptake and the illustration of skeletal/bone marrow metastases as diffuse and/or focal increased uptake, especially focal/tubular MIBI activity of the femoral marrow.     

Phase analysis by gated F-18 FDG PET/CT for left ventricular dyssynchrony assessment: a comparison with gated Tc-99m sestamibi SPECT

Purpose

To investigate the value of gated F-18 FDG PET/CT on left ventricular (LV) dyssynchrony assessment in comparison with gated Tc-99m sestamibi SPECT in patients with coronary artery disease (CAD).

Methods

The data of 100 consecutive CAD patients who underwent both gated myocardial Tc-99m sestamibi SPECT and F-18 FDG PET/CT imaging were analyzed. Phase standard deviation (SD) and histogram bandwidth (BW) were derived from phase analysis using Cedars software package. The correlation and agreement of SD and BW between Tc-99m sestamibi SPECT and F-18 FDG PET/CT were examined. Myocardial viability and the site of latest activation assessed by the two imaging methods were compared as well.

Results

A moderate correlation for SD (r = 0.58, p < 0.0001) and BW (r = 0.60, p < 0.0001) was found between gated SPECT and gated F-18 FDG PET/CT. Bland–Altman analysis revealed an overestimation of SD and BW (6.4° ± 14.3° and 22.0° ± 46.8°) by gated F-18 FDG PET/CT. Multivariate logistic regression analysis identified that significant LV remodeling on SPECT imaging, LV functional parameters and F-18 FDG uptake ratio of myocardium to blood pool (SUV_M/B) were associated with the overestimation. Myocardial SPECT and F-18 FDG PET/CT had a 67.1 % identity in determining the latest activation site and 5.2 % more viable myocardium was detected by F-18 FDG PET/CT than SPECT.

Conclusion

Gated F-18 FDG PET/CT moderately correlated with gated Tc-99m sestamibi SPECT in assessing LV dyssynchrony. Gated F-18 FDG PET/CT phase analysis should be cautiously applied in CAD patients with significant LV remodeling on SPECT imaging, severe LV functional impairment or poor myocardial F-18 FDG uptake.     

Gaucher's disease type 1: assessment of bone involvement by CT and scintigraphy

The effectiveness of CT and technetium-99m sulfur colloid (99mTc SC) bone-marrow scans in determining the extent and severity of skeletal involvement in 23 patients with type 1 Gaucher's disease was compared with the effectiveness of conventional radiographic techniques and technetium-99m methylene diphosphonate (99mTc MDP) bone scintigrams. Density measurements obtained by CT proved sensitive in differentiating normal marrow (-50 to -120 H). Scintigrams with the sulfur colloid nuclide demonstrated three distinct patterns of uptake: peripheral expansion of normal marrow (profile B), greater marrow expansion with patchy areas lacking uptake (profile C), and greater loss of uptake with retention of the nuclide in other reticuloendothelial organs and circulation (profile D). CT scans provided greater sensitivity in resolving the extent of marrow involvement in affected areas, while the 99mTc SC scintigrams were more effective in overall assessment of the severity of bone-marrow involvement. Both conventional radiographic techniques and 99mTc MDP bone scans were useful primarily as screening procedures or for evaluating specific involved areas. 99mTc MDP scans were useful in evaluating regional defects (i.e., ischemic necrosis) in certain cases, but no consistent patterns were observed. CT and 99mTc SC scans are useful for determining the extent and severity of Gaucher's disease involvement of bone marrow.