Diagnostic performance of 18F-fluciclovine PET/CT for regional lymph node metastases in patients with primary prostate cancer: a multicenter phase II clinical trial

OBJECTIVE

This multicenter, phase II clinical trial evaluated the diagnostic performance of 18F-fluciclovine, a novel amino acid for positron-emission tomography (PET), for detection of small lymph node metastases with short-axis diameters of 5-10 mm in patients with prostate cancer.

METHODS

Patients with prostate cancer were eligible after screening of laboratory tests and pelvic contrast-enhanced computed tomography (CT). Pelvic region 18F-fluciclovine PET/CT was then acquired within 28 days and dissection of regional lymph nodes was performed within 60 days of pelvic contrast-enhanced CT. Diagnostic performance of 18F-fluciclovine-PET/CT was evaluated by comparison with standard histopathology of lymph nodes.

RESULTS

In a total of 28 patients, 40 regional lymph nodes with short-axis diameters of 5-10 mm were eligible for efficacy evaluation; seven of these showed metastases confirmed by histopathology. The sensitivity of 18F-fluciclovine PET/CT was 57.1% (4/7). All four true positive lymph nodes detected by 18F-fluciclovine PET/CT had a metastatic lesion with a long-axis diameter of ≥7 mm and a high proportion of cancer volume (60-100%) according to pathology evaluation. The specificity, diagnostic accuracy, positive predictive value, and negative predictive value of 18F-fluciclovine PET/CT in lymph node-based analysis were 84.8% (28/33), 80.0% (32/40), 44.4% (4/9), and 90.3% (28/31), respectively. No clinically significant adverse events occurred.

CONCLUSIONS

18F-fluciclovine PET/CT detected small lymph node metastases; however it also showed positive findings in benign lymph nodes. Refinement of the image assessment criteria may improve the diagnostic performance of 18F-fluciclovine PET/CT for small lymph node metastases in patients with prostate cancer.

Biodistribution of N-lsopropyl-p-lodoamphetamine in the Rat Brain

The biodistribution of N-isopropyl-p-iodoamphetamine (IMP) was studied in the rat brain.131 l-labelled IMP was injected intravenously in awake animals. Activities in the brain of Sprague-Dawley rats were 2.68–3.22 (% dose/g) in the cortex and 0.59–0.66 (% dose/g) in the white matter at 1 min p. i. Activities in the cortex were slightly increased at 60 min p. i., while activities in the white matter increased markedly at 60 min and 6 h p. i. Therefore, the cerebral cortex-to-white matter ratio decreased from 5 to 1 within 60 min after injection. Autoradiograms of the rat brain at 1–10 min p. i. showed high contrasts. Activities were high in the cortex and low in the white matter, but homogeneous at 60 min – 6 h. IMP seems to be a useful agent for cerebral perfusion imaging in the early phase after injection. Knowledge of biodistribution of this agent is considered to be indispensable for the interpretation of images.

Detection of thyroid cancer by an FDG-PET cancer screening program: a Japanese nation-wide survey

BACKGROUND/AIM

The [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) cancer screening program is defined as a cancer screening for asymptomatic subjects using FDG-PET (including PET/ computed tomography [CT]) with or without combination of other screening tests. The aim of the present study was to analyze the thyroid cancer detection rate in asymptomatic individuals through a FDG-PET cancer screening program in Japan.

MATERIALS AND METHODS

A total of 153,775 asymptomatic individuals underwent FDG-PET cancer screening. We analyzed 1,308 cases for possible thyroid cancer in all screening tests.

RESULTS

Among the 1,308 possible cases, 353 were verified as thyroid cancer. The relative sensitivity and positive predictive value (PPV) of FDG-PET were 90.7% and 29.5% for thyroid cancer, respectively. The relative sensitivity was equivalent to thyroid ultrasonography (US) (90.9%) and higher than neck computed tomography (CT) (75.7%, p<0.001), thyroglobulin (36.1%, p<0.001), and carcinoembryonic antigen (5.6%, p<0.001). The sensitivity with a PET/CT scanner was higher than that with a dedicated PET scanner (94.1% vs. 85.0%, p<0.001). Combining thyroid US with FDG-PET increased the relative sensitivity and PPV. The majority of thyroid carcinomas detected by FDG-PET screening were Union for International Cancer Control (UICC) stage I, but a significant number of cases were also detected as stage III or IV.

CONCLUSION

The FDG-PET cancer screening program in Japan detected thyroid cancer at an early stage. FDG-PET showed high sensitivity in detecting thyroid cancer, and it may be more effective if combined with thyroid US.

Detection of lung cancer by FDG-PET cancer screening program: a nationwide Japanese survey

AIM

The aim of this study was to analyze the lung cancer detection rate in asymptomatic individuals by the Fluorine-18 fluorodeoxyglucose-positron emission tomography FDG-PET cancer screening program in Japan.

MATERIALS AND METHODS

A total of 153,775 asymptomatic individuals underwent the FDG-PET cancer screening program; the 854 cases with findings that indicated suspected lung cancer by any detection method were analyzed.

RESULTS

Among the 854 cases, 319 were verified as lung cancer. The relative sensitivity and positive predictive value (PPV) of FDG-PET were 86.5% and 38.9% for lung cancer, respectively. The sensitivity of PET/computed tomography (CT) scanner was higher than that of dedicated PET (100.0% vs. 63.2%), indicating that CT imaging was effective for lung cancer screening. The majority of lung carcinomas detected by FDG-PET screening were UICC stage IA or IB, but detection of smaller or less invasive carcinomas was limited.

CONCLUSION

The FDG-PET screening program in Japan detected lung cancer at an early stage.

Detection of prostate cancer by an FDG-PET cancer screening program: results from a Japanese nationwide survey

OBJECTIVES

The aim of this study was to analyze detection rates and effectiveness of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) cancer screening program for prostate cancer in Japan, which is defined as a cancer-screening program for subjects without known cancer. It contains FDG-PET aimed at detection of cancer at an early stage with or without additional screening tests such as prostate-specific antigen (PSA) and magnetic resonance imaging (MRI).

METHODS

A total of 92,255 asymptomatic men underwent the FDG-PET cancer screening program. Of these, 504 cases with findings of possible prostate cancer in any screening method were analyzed.

RESULTS

Of the 504 cases, 165 were verified as having prostate cancer. Of these, only 61 cases were detected by FDG-PET, which result in 37.0% relative sensitivity and 32.8% positive predictive value (PPV). The sensitivity of PET/computed tomography (CT) scanner was higher than that of dedicated PET (44.0% vs. 20.4%). However, the sensitivity of FDG-PET was lower than that of PSA and pelvic MRI. FDG-PET did not contribute to improving the sensitivity and PPV when performed as combined screening.

CONCLUSION

PSA should be included in FDG-PET cancer screening programs to screen for prostate cancer.

The current status of an FDG-PET cancer screening program in Japan, based on a 4-year (2006-2009) nationwide survey

Objective

The aim of this study was to survey the 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening program conducted in Japan.

Methods

The “FDG-PET cancer screening program” included both FDG-PET and positron emission tomography with computed tomography (PET/CT) with or without other combined screening tests that were performed for cancer screening in asymptomatic subjects. A total of 155,456 subjects who underwent the FDG-PET cancer screening program during 2006–2009 were analyzed.

Results

Of the 155,456 subjects, positive findings suggesting possible cancer were noted in 16,955 (10.9 %). The number of cases with detected cancer was 1,912 (1.23 % of the total screened cases, annual range 1.14–1.30 %). Of the 1,912 cases of detected cancer, positive findings on FDG-PET were present in 1,491 cases (0.96 % of the total number of screened cases). According to the results of further examinations, the true positive rate for subjects with suggested possible cancer (positive predictive value) was 32.3 % with FDG-PET. Cancers of the colon/rectum, thyroid, lung, and breast were most frequently found (396, 353, 319, and 163 cases, respectively) with high PET sensitivity (85.9, 90.7, 86.8, 84.0 %, respectively). Prostate cancer and gastric cancer (165 and 124 cases, respectively) had low PET sensitivity (37.0 and 37.9 %, respectively). The Union for International Cancer Control (UICC) clinical stage of cancer found with the FDG-PET cancer screening program was mainly Stage I.

Conclusions

The FDG-PET screening program in Japan has detected a variety of cancers at an early stage. However, several cancers were found in repeated FDG-PET cancer screening program, indicating the limitation of a one-time FDG-PET cancer screening program. The value of the FDG-PET cancer screening program is left to the judgment of individuals with regard to its potentials and limitations.

Analysis of various malignant neoplasms detected by FDG-PET cancer screening program: based on a Japanese Nationwide Survey

OBJECTIVE

The most distinctive feature of FDG-PET cancer screening program is the ability to find various kinds of malignant neoplasms in a single test. The aim of this survey is to clarify the range and frequency of various malignant neoplasms detected by FDG-PET cancer screening performed in Japan.

METHODS

"FDG-PET cancer screening" was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. This survey was based on a questionnaire regarding FDG-PET cancer screening. We analyzed the situation of 9 less frequently found malignant neoplasms including malignant lymphoma, malignancy of head and neck, esophagus, hepatobiliary and gallbladder, pancreas, kidney, cervical and uterine, ovary, and bladder.

RESULTS

The detailed information of subjects with the suspected 9 kinds of malignant neoplasms mentioned above in the FDG-PET cancer screening program was studied in a total of 1,219 cases from 212 facilities. A statistical significance between PET/CT and PET was found in relative sensitivity and PPV for renal cell cancer. Malignant lymphoma was frequently of indolent type, suspected head and neck cancers had many false-positive results, and pancreatic cancer detected in this program was often in the advanced stage even in asymptomatic subjects. The recommendation of combined screening modality to PET or PET/CT was as follows: gastric endoscopy for assessing early esophageal cancer; abdominal ultrasound for screening hepatobiliary and gallbladder cancer; pelvic magnetic resonance imaging for assessing gynecological and pelvic cancers; and the CA125 blood test for screening ovarian cancer. Delayed image was helpful depending on the type of suspected malignant neoplasm.

CONCLUSION

We analyzed various types of malignant neoplasms detected by the FDG-PET cancer screening program and presented recommended combination of examinations to cover FDG-PET and PET/CT.

[Assessment of diagnostic criteria for FDG-PET cancer screening program according to the interpretation of FDG-PET and combined examination]

OBJECTIVE

The aim of this study is to establish the diagnostic criteria for FDG-PET cancer screening program of four kinds of organ (breast, thyroid, lung and colon/rectum) according to the interpretation of FDG-PET cancer screening program of the case with proved clinical outcome.

METHODS

Among FDG-PET cancer screening examinations performed in two PET centers during 2003 to 2006, two hundreds of examinations with proved clinical outcome were evaluated. Interpretation of breast ultrasonography, thyroid ultrasonography, chest CT and fecal occult blood testing, which were regarded as combined examinations, were performed together with the interpretation of FDG-PET images.

RESULTS

As a result of the interpretation, localized FDG accumulating site in all four organs should be recommended for further inspections. In addition, essential point for diagnosis was considered as follows; (1) check over the slight localized FDG accumulation with screening of breast region, (2) combine chest CT with FDG-PET for the evaluation of lung region and (3) check up the shift of FDG accumulation between early and delayed phase with screening of colon/rectum region.

CONCLUSIONS

According to the interpretation results of this study, we establish diagnostic criteria of FDG-PET and combined examination of four kinds of organ.

Performance profile of FDG-PET and PET/CT for cancer screening on the basis of a Japanese Nationwide Survey

OBJECTIVE

The aim of this study is to survey the situation of (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening in Japan and to describe its performance profile.

METHODS

"FDG-PET for cancer screening" was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. We sent questionnaires regarding FDG-PET cancer screening to 99 facilities in which FDG-PET tests were performed during the fiscal year 2005. Replies were obtained from 68 of the 99 facilities, of which 46 facilities performed FDG-PET cancer screening. The total number of subjects who underwent FDG-PET cancer screening was 50 558. From 38 of 46 facilities, reliable results of thorough examinations were obtained for the subjects who were positive by FDG-PET and/or one or more of the combined screening tests was performed and were referred for further evaluation. The total number of subjects in these 38 facilities amounted to 43 996.

RESULTS

A total of 50,558 healthy subjects underwent FDG-PET (including PET/CT) scanning with or without other tests for cancer screening in 46 PET centers during the fiscal year of 2005 in Japan. Thorough examination was indicated for 9.8% of the cases as a result of positive findings suggesting possible cancer. On analyzing 43 996 cases from 38 PET centers from which detailed information was obtained, 500 cases of cancers (1.14%) were found, of which 0.90% were PET positive and 0.24% were PET negative, resulting in the relative sensitivity of PET being 79.0%. Cancers of the thyroid, colon/rectum, lung, and breast were most frequently found (107, 102, 79, and 35 cases, respectively) with high PET sensitivity (88%, 90%, 80%, and 92%). PET showed an overall positive predictive value of 29.0%. PET/CT had a better detection rate, sensitivity, and positive predictive value than dedicated PET (P < 0.01).

CONCLUSIONS

We were able to clarify the performance profile of "FDG-PET for cancer screening" on the basis of a Japanese nationwide survey. The number of facilities possessing PET is increasing steadily, highlighting the necessity of evaluating the usefulness of "FDG-PET cancer screening" as soon as possible by undertaking long-term investigations of large series of subjects.

FDG PET Findings of Chronic Myeloid Leukemia in the Chronic Phase Before and After Treatment

We report 2 patients with chronic myeloid leukemia in the chronic phase showing diffusely increased F-18 fluorodeoxyglucose (FDG) uptake in the bone marrow before treatment. Follow-up FDG positron emission tomography (PET) scans were performed in a patient after cessation of treatment and in the other under treatment. Both FDG PET findings showed reduced FDG uptake in the bone marrow. A series of these FDG PET findings suggest the usefulness of FDG PET for the diagnosis and monitoring of chronic myeloid leukemia after treatment.

The efficacy of whole-body FDG-PET or PET/CT for autoimmune pancreatitis and associated extrapancreatic autoimmune lesions

PURPOSE

The aim of this study was to evaluate retrospectively the efficacy of whole-body (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) for autoimmune pancreatitis (AIP) and associated extrapancreatic autoimmune lesions.

METHODS

Whole-body FDG-PET or PET/computed tomography (CT) findings were reviewed in six patients with AIP. The initial PET scans were performed 1 h and 2 h after FDG injection in all six patients. Follow-up PET scans were performed during or following steroid therapy in five patients and in one patient who did not have steroid therapy.

RESULTS

The initial PET scans revealed intense FDG uptake by AIP in all six patients. The maximum standardized uptake value (SUVmax) increased in four patients and was stable in two patients. The intense uptake in the pancreas disappeared during or following steroid therapy in five patients and in one patient who showed spontaneous remission of AIP. Abnormal FDG uptake by extrapancreatic autoimmune diseases was observed in five of the six patients: sclerosing sialadenitis (n = 5), lymphadenopathy (n = 5), retroperitoneal fibrosis (n = 2), interstitial nephritis (n = 2) and sclerosing cholecystitis (n = 1). Abnormal FDG uptake disappeared in the salivary glands (n = 4), lymph nodes (n = 4), retroperitoneum (n = 2), kidneys (n = 1) and gallbladder (n = 1) during or following steroid therapy and remained in the salivary glands and lymph nodes of a spontaneous remission patient.

CONCLUSION

These results suggest that whole-body FDG-PET may be useful for detecting AIP and associated extrapancreatic autoimmune lesions and for monitoring their disease activity but that dual time point imaging may not be useful for differentiating malignancy from AIP.

18F-Fluorodeoxyglucose Positron Emission Tomography Features of Idiopathic Retroperitoneal Fibrosis

OBJECTIVE

To evaluate the 18F-fluorodeoxyglucose (FDG) uptake features of idiopathic retroperitoneal fibrosis (IRF).

METHODS

18F-Fluorodeoxyglucose positron emission tomographic (PET) or PET/computed tomographic findings were retrospectively reviewed in 6 patients with IRF. FDG PET or PET/computed tomography was performed 1 and 2 hours after FDG injection. The FDG level was scored using a 4-point scale, and the intensity of FDG uptake was quantified using the maximum standardized uptake value (SUVmax).

RESULTS

In the 1-hours images, intense FDG uptake by IRF was observed in 5 patients before steroid treatment, but no abnormal uptake was noted in 1 patient receiving steroid treatment. The SUVmax in IRF increased from a mean +/- SD of 6.0 +/- 1.2 (range, 4.9-7.6) to 7.6 +/- 1.1 (range, 5.9-8.2) for all 4 patients who underwent 1 and 2 hours dual-time point imaging. Abnormal uptake was also noted in the mediastinum and the pancreas in 1 and 2 patients, and the diagnoses of mediastinal fibrosis and autoimmune pancreatitis were made, respectively. The SUVmax was stable or increased in the 3 lesions of mediastinal fibrosis and autoimmune pancreatitis.

CONCLUSION

FDG PET may be a reliable means of evaluating disease activity and the extent of IRF, but dual-time point imaging may not be useful to differentiate malignancy from IRF.

[Performance profile of FDG-PET and PET/CT for cancer screening based on a Japanese nationwide survey]

A total of 50,558 healthy subjects underwent an FDG-PET (including PET/CT) scan with or without combination of other tests for cancer screening in 46 PET centers during fiscal year of 2005 in Japan. Thorough examination was indicated for 9.8% of the cases due to positive findings suggesting possible cancer. On analyzing 43,996 cases from 38 PET centers, where detailed information was obtained, 500 cases of cancers (1.14%) were found, of which 0.90% was PET positive and 0.24% was PET negative, resulting in the relative sensitivity of PET being 79.0%. Cancers of thyroid, colon/rectum, lung and breast were most frequently found (107, 102, 79, 35 cases, respectively) with high PET sensitivity (88%, 90%, 80%, 92%). PET showed an overall positive predictive value of 29.0%. PET/CT had better detection rate, sensitivity, and positive predictive value than dedicated PET (p<0.01).

FDG PET and PET/CT Monitoring of Autoimmune Pancreatitis Associated With Extrapancreatic Autoimmune Disease

We report a series of FDG PET findings of a 69-year-old male patient with autoimmune pancreatitis (AIP) associated with extrapancreatic disease. The first FDG PET revealed diffuse uptake of FDG in AIP and retroperitoneal fibrosis (RF). The second FDG PET after cessation of steroid treatment indicated subsiding of disease activity in AIP, continuous disease activity in RF, and new extrapancreatic lesions, including enlargement of a right salivary gland, nephritis, and lymphadenopathy. The last FDG PET under steroid treatment revealed reduced FDG uptake in the above abnormal FDG uptake lesions. A series of these FDG PET findings suggest the usefulness of FDG PET for the diagnosis and monitoring of AIP associated with extrapancreatic autoimmune diseases.

Role of positron emission tomography in decisions on treatment strategies for pancreatic cancer

BACKGROUND/PURPOSE

The purpose of this study was to estimate the usefulness of positron emission tomography (PET) in deciding on strategies for the treatment of pancreatic cancer. The following two parameters were evaluated: the ability of PET to provide an estimation of the progression of pancreatic cancer, and the ability of PET to predict survival and the effect of chemoradiotherapy.

METHODS

Forty-two patients underwent PET as part of the procedure for making a diagnosis of pancreatic tumors. The maximum standardized uptake value (SUVmax) levels were compared with clinicopathological factors and analyzed.

RESULTS

PET provided a sensitivity of 87%, a specificity of 67%, and an overall accuracy of 85% for the diagnosis of pancreatic malignancy. Tumors with distant metastases showed significantly higher SUV levels than tumors without metastasis. In the patients who received chemoradiotherapy, the overall survival of the group in which SUVmax was less than 7.0 was better than that of the group in which SUVmax was more than 7.0.

CONCLUSIONS

We conclude that PET is a useful tool for determining pathological status and distant metastasis in pancreatic cancer, and for predicting the prognosis of patients receiving chemoradiotherapy.

Decreased cerebral blood flow and prognosis of Alzheimer's disease: A multicenter HMPAO-SPECT study

PURPOSE

To determine the usefulness of brain perfusion SPECT for evaluating the severity and progression of Alzheimer's disease (AD).

METHODS

Eighty-four AD patients were included. At entry, 99mTc-HMPAO-SPECT, the Mini Mental State Examination (MMSE), Mental Function Impairment Scale (MENFIS), and the Raven Colored Progression Matrix (RCPM) were performed for all 84 patients. During the follow-up periods, two individual MMSE evaluations in 34 patients, two MENFIS evaluations in 30 patients, and two RCPM evaluations in 20 patients were performed. Based on the regions of decreased cerebral blood flow demonstrated on 3D-SSP images of SPECT, the cases were classified as type A (no decrease), type B (decreased blood flow in the parietal or temporal lobe), type C (decreased blood flow in the frontal lobe and parietal or temporal lobe), type Pc (decreased blood flow in posterior cingulate gyrus only), and "other types". The types of decreased blood flow, scores on neuropsychological evaluations, and symptom progression were analyzed.

RESULTS

The MENFIS, MMSE, and RCPM scores were poorest in type C patients at entry. The degree of decrease of these scores during the follow-up periods was also greatest in type C. The greatest difference between patients with and without rapid progression in SPECT data of the mild AD patients (MMSE score > or = 24) was in the frontal lobe.

CONCLUSION

Decreased blood flow in the frontal lobe of AD patients is correlated not only with reduced cognitive function at the time of the evaluation but with rapid progression in the subsequent clinical course.

18F-FDG PET/CT findings of a right subphrenic foreign-body granuioma

We report a case of an 85-year-old woman with a foreign-body granuloma which accumulated 18F-fluorodeoxyglucose (FDG). Unenhanced computed tomography showed a hyperdense mass with a hypodense rim in the right subphrenic space. FDG PET/CT images showed intense FDG uptake in the hypodense rim and little FDG uptake in the center of the mass, showing a ring-shaped appearance. The fusion imaging of FDG PET/CT represented the metabolic features of the foreign-body granuloma. When a ring-shaped FDG uptake is noted in the abdomen of a patient with a history of abdominal surgery, a foreign-body granuloma should be included in the differential diagnosis.

Cerebral blood flow abnormalities induced by transient hypothyroidism after thyroidectomy —analysis by Tc-99m-HMPAO and SPM96—

The current study is an investigation of alterations in regional cerebral blood flow (rCBF) distribution in patients with transient hypothyroidism after thyroidectomy. In addition, the effects of thyroxine treatment on rCBF changes were studied.

METHODS

Noninvasive rCBF measurements using 99mTc-HMPAO SPECT were performed on 24 post-thyroidectomy patients who were in a hypothyroidic state. The measurements were conducted before 131I therapy and after thyroid hormone (thyroxine) replacement. We used adjusted rCBF images (normalization of global CBF for each subject to 50 ml/100 g/min with proportional scaling) to compare these data with age-matched normal control groups (n =15) using SPM96. We also compared the absolute rCBF value of hypothyroidic patients with those of normal control groups. In addition, the association between rCBF alteration and the severity of depression was also analyzed. Finally, the effect of thyroid hormone replacement on rCBF was investigated individually using the Jack-knife test, in which patient data were compared with those from healthy volunteers. According to the result of this test, all cases were categorized into three subgroups, namely, improved, unchanged group and normal. To prove the reversibility of rCBF alteration after thyroid hormone replacement, a group comparison test between the normal controls and the improved group was done before and after thyroid hormone replacement. Similarly a group comparison test between the unchanged group and normal controls was also performed.

RESULTS

In the hypothyroidic condition, there was a significant decrease in the posterior part of the bilateral parietal lobes and in part of the bilateral occipital lobes, including the cuneus. These decreased rCBF areas extended to the bilateral prefrontal cortices as deterioration became more profound. On individual analysis, 16 of 24 patients (66.7%) demonstrated rCBF reduction, while 8 patient did not show significant rCBF change (33.3%, the normal group). After thyroxine replacement, improvement of rCBF was noted in nine of 16 patients (56.3%, the improved group). In seven of 16 patients (43.7% the unchanged group), the significant low rCBF area remained unchanged. Compared with the normal controls, the improved group showed significantly decreased rCBF of the bilateral parietal lobe and the occipital lobe in the hypothyroic condition. After thyroid hormone replacement, these abnormal rCBF areas disappeared. In contrast, in the unchanged group, the significant hypoperfusion area became localized but remained.

CONCLUSION

99mTc-HMPAO SPECT and SPM96 analysis demonstrated a significant rCBF decrease in the parietal lobe and part of the occipital lobe in patients with induced transient hypothyroidism after thyroidectomy. This phenomenon might contribute to understanding of the depressive state. Recovery of rCBF after thyroid hormone replacement was confirmed in some patients. However, rCBF improvement did not always occur in every patient during the follow up period. The reversibility of rCBF in transient hypothyroidism may be dependent on individual characteristics during a short-term period.

Parathyroid scintigraphy with 99mTc-MIBI and 123I subtraction: a comparison with magnetic resonance imaging and ultrasonography

The aim of this study was to evaluate the efficacy of 99mTc-MIBI and 123I subtraction scintigraphy for the detection of abnormal parathyroid glands to be referred for surgical treatment. Thirty-nine consecutive patients, including 35 primary and four secondary cases of hyperparathyroidism, were evaluated. 99mTc-MIBI/123I subtraction scintigraphy (MIBI/I) was performed on all patients, and the results were compared with delayed images of 99mTc-MIBI (D-MIBI), magnetic resonance imaging (MRI) and ultrasonography (US). The overall sensitivity of MIBI/I, MRI, US and D-MIBI was 55.9%, 43.4%, 50.8% and 39.0%, respectively. In cases of single-gland disease, the sensitivity of MIBI/I, MRI, US and D-MIBI was 62.1%, 48.3%, 55.2% and 44.8%, respectively. In cases of multi-gland disease, the sensitivity of MIBI/I, MRI, US and D-MIBI was 50.0%, 37.5%, 46.7% and 36.7%, respectively. In cases of parathyroid adenoma, the sensitivity of MIBI/I, MRI, US and D-MIBI was 71.4%, 50.0%, 71.4% and 50.0%, respectively. In cases of parathyroid hyperplasia, the sensitivity of MIBI/I, MRI, US and D-MIBI was 55.2%, 42.3%, 50.0% and 39.7%, respectively. It is concluded that 99mTc-MIBI/123I subtraction is more useful than the delayed imaging of 99mTc-MIBI, MRI and US.

A novel radiopharmaceutical for detection of malignant melanoma, based on melanin formation: 3-iodo-4-hydroxyphenyl-L-cysteine

The aim of this study was to develop a new artificial amino acid radiopharmaceutical labelled with radioiodine for detection of malignant melanoma, based on melanin formation. By considering the affinity for tyrosinase, a starting enzyme on the branching point to melanin biosynthesis, 3-[125I]iodo-4-hydroxyphenyl-L-cysteine (125I-L-PC) was synthesized and evaluated biologically. Labelling of 125I-L-PC using the chloramine-T method was carried out conveniently and efficiently in a short period of time, with high specific activity. In a biodistribution study, 125I-L-PC showed a low accumulation in normal tissue and relative retention in B16 melanoma. A high contrast image of peripheral tumour was obtained during autoradiography. During an in vitro accumulation study, inhibition of 125I-L-PC with a tyrosinase inhibitor suggested interaction of this tracer with tyrosinase. It indicates that the uptake mechanism of 125I-L-PC to melanoma tissue was dependent on high tyrosinase activity in melanoma cells. Thus, 125I-L-PC appears to be a promising radioiodinated amino acid radiopharmaceutical for imaging malignant melanoma in relation to melanin formation, namely specific metabolism with high tyrosinase activity.

[The development of new method for the assessment of perfusion reserve using split dose iodine-123-IMP SPECT: one-day protocol by modified ARG method]

Evaluation of the regional cerebrovascular reactivity (rCVR) to a cerebral vasodilatory stimulus is important in the investigation of patients with ischemic cerebrovascular disease. We devised a simplified one-day protocol technique using [123I]N-isopropyl-p-iodoamphetamine (IMP) autoradiography (ARG) with SPECT. To validate the accuracy of IMP-ARG for quantifying rCVR to acetazolamide, we compared rCVR measured using IMP-ARG with rCVR calculated using IMP split dose method of microsphere model. Twenty patients with chronic steno-occlusive disease in a unilateral major cerebral artery underwent 123I-SPECT. On rCBF SPECT image above 3.5 cm from OM line, large cortical regions of interest (ROI) was bilaterally determined for bilateral middle cerebral artery and anterior cerebral artery. Based on rCBF values in each ROI, rCVR to acetazolamide was calculated. Significant correlation was observed between rCVR values obtained using IMP-ARG and microsphere model IMP methods in the 80 ROIs examined in the 20 patients (r = 0.72; p < 0.001). The result demonstrated that [123I]IMP-ARG split dose method can quantify rCVR non-invasively in a short time.

Prediction of plasma concentration-time curve of orally administered theophylline based on a scintigraphic monitoring of gastrointestinal transit in human volunteers

The plasma concentration-time profile of theophylline after oral administration in human volunteers was predicted using the individual gastrointestinal (GI) transit data monitored by a gamma scintigraphic technique. Theophylline was administered as aminophylline under fasted and fed condition, along with 99mTc-labeled diethylenetriamine-pentaacetic acid (DTPA), an unabsorbable marker to evaluate the GI transit by a gamma scintigraphic technique. Two healthy male volunteers participated under fasted and fed conditions in a crossover study. The GI transit was evaluated by dividing the GI tract to four segments, stomach, jejunum, ileum and cecum/colon. Under the fed condition, the GI transit pattern for each segment was confirmed to alter considerably, causing a delay in the gastric emptying mainly. Further, the plasma concentration curves of theophylline after oral administration were predicted using the GI-Transit-Absorption Model on the basis of individual GI transit parameters calculated by the fitting of the observed data to the GI-Transit Kinetic Model. The absorption rate constant in each segment and the pharmacokinetic parameters after intravenous administration used for the prediction were the values extrapolated from the data in rats and the ones normalized from the values in literatures, respectively. The plasma concentration-time curves for theophylline were well predicted using obtained individual GI transit parameters. The analysis using this method could estimate the variable absorption behavior governed by the GI transit in detail.

Serial change in 123I-MIBG myocardial scintigraphy in non-insulin-dependent diabetes mellitus

PURPOSE

We performed 123I-MIBG (MIBG) myocardial scintigraphy twice in patients with non-insulin-dependent diabetes mellitus (NIDDM) to investigate whether MIBG distribution was improved by pertinent clinical control. To determine the influential factors for MIBG distribution, we investigated the association between various clinical parameters and the serial change in MIBG uptake parameters.

PATIENTS AND METHODS

Twenty NIDDM patients with no cardiac disorders were evaluated. Planar images were taken at 30 minutes (early) and 3 hours (delayed) after MIBG injection. The heart-to-upper-mediastinum uptake ratio (H/M) and washout ratio (WR) were calculated as parameters for estimating cardiac sympathetic function. Patients were divided into two groups, eight in the improved group and twelve in the unimproved group, according to the serial change in H/M. The mean interval between the baseline and the follow up study was 2.1 +/- 0.6 year. Differences between the means of the laboratory data in patients in both groups were compared for the baseline and the follow up study by using the paired t-test. As a means of determining the influential factors for a serial change of MIBG uptake, Fisher's exact test was performed to evaluate the association between the serial change in cardiac MIBG parameters and changes in other clinical parameters, such as blood sugar (BS) control, BS control method (insulin therapy), serum cholesterol control, and severity of diabetic complications. We also analyzed the association between the changes in CV(R-R) (coefficient variance of R-R intervals at rest ECG) or NCV (velocity of posterior tibial nerve) and those of other clinical parameters. Associations among these neurological parameters (MIBG parameters, CV(R-R) and NCV) were also analyzed.

RESULTS

Paired t-tests showed a significant decrease in fasting blood sugar and fructosamine in the improved group in the follow up study compared to those in the baseline study. Nevertheless, Fisher's exact test showed no significant association between FBS, HbA1C, fructosamine and the improvement in cardiac MIBG uptake. The only significant association was observed between the serial change in H/M and the BS-control method (insulin therapy). Within the neurological parameters, a significant association was noted between the serial changes in H/M and CV(R-R).

CONCLUSION

Although BS control was likely to be an important factor, it did not always ameliorate cardiac MIBG uptake. Based on the significant association between the BS-control method (insulin therapy) and MIBG uptake change, the severity of diabetes mellitus was likely to be a more influential factor. It was suggested that cardiac MIBG uptake could improve within the mild stage if controlled by diet therapy or an oral hypoglycemic agent in NIDDM.

The correlation between 99mTc-MIBI uptake and MIB-1 as a nuclear proliferation marker in glioma--a comparative study with 201Tl

Technetium-99m methoxy-isobutylisonitrile (MIBI), like thallium-201 (201Tl), is a highly efficient agent for the diagnosis and monitoring of glioma tumors. Although 201Tl uptake is known to be partly associated with proliferative activity, little is known about the correlation between MIBI uptake and proliferation activity in gliomas. The current study was performed to assess the correlation between MIBI uptake and proliferative activities in gliomas, estimated by the monoclonal antibody to Ki-67 antigen (MIB-1) staining method. By comparing the results with those of 201Tl, we determined which tracer would be suitable for estimating proliferative activities. Twenty-four presurgical glioma patients (six with low-grade gliomas, five with anaplastic astrocytomas, and 13 with glioblastomas) were given MIBI and 201Tl SPECT. Early (10 min after injection) and delayed images (3 h after injection) were obtained for both MIBI and 201Tl scintigraphy. SPECT parameters, early ratio (ER), delayed ratio (DR), and retention index (RI) were obtained in both radiopharmaceuticals. All patients underwent subsequent surgical excision, and the specimens were immunostained for MIB-1. The proliferative activity was measured as a percentage positive nuclear area for MIB-1 (MI; MIB-1 index). To evaluate the relationship between the proliferative activity and SPECT parameters, we performed a correlation analysis. MI correlated with the MIBI uptake ratio (r = 0.75 for ER, and r = 0.7 for DR). Both DR and RI of 201Tl also correlated with MI, but weakly (r = 0.6 for DR, and. r = 0.59 for RI). There was no significant correlation between the MIB-1 index and the other parameters. MIBI-uptake parameters demonstrated a stronger positive correlation with the MIB-1 index than that of 201Tl. With the use of MIBI SPECT, we can estimate the proliferative activity of glioma noninvasively.

Technetium-99m tetrofosmin for parathyroid scintigraphy: a direct comparison with (99m)Tc-MIBI, (201)Tl, MRI and US

The aim of this study was to evaluate the efficacy and role of technetium-99m tetrofosmin for the detection of abnormal parathyroid glands to be referred for surgical treatment. Twenty-eight consecutive patients, including 25 primary and 3 secondary cases of hyperparathyroidism, were evaluated. (99m)Tc-tetrofosmin/(99m)Tc-pertechnetate subtraction scintigraphy (TF/Tc) was performed on all patients, and the results were directly compared with those of (99m)Tc-methoxyisobutylisonitrile (MIBI)/(99m)Tc-pertechnetate subtraction scintigraphy (MIBI/Tc), (201)Tl/(99m)Tc-pertechnetate subtraction scintigraphy (Tl/Tc), magnetic resonance imaging (MRI) and ultrasonography (US). In cases of single-gland disease, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 63.2%, 68.4%, 57.9%, 55.6% and 63.2%, respectively. In cases of multi-gland disease, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 41.7%, 41.7%, 37.5%, 58.3% and 54.2%, respectively. In cases of parathyroid adenoma, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 68.8%, 75.0%, 68.8%, 62.5% and 75.0%, respectively. In cases of parathyroid hyperplasia, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 40.7%, 40.7%, 33.3%, 53.8% and 48.1%, respectively. It is concluded that, for the detection of abnormal parathyroid glands, (99m)Tc-tetrofosmin is as useful as (99m)Tc-MIBI and is more useful than (201)Tl.

[Reevaluation of 201Tl-SPECT for patients with solitary pulmonary nodule--comparison study with biopsy method and tumor marker measurement]

We compared the differential diagnostic capabilities of 201Tl-SPECT and biopsy methods and serum tumor marker in 125 patients with solitary pulmonary lesions composed of 87 lung cancer and 38 benign lesions. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 201Tl-SPECT were 76%, 95%, 97%, 63%, and 82%, respectively. These parameters are similar in biopsy methods. Although sensitivity improved to be 85% by the combination with tumor marker methods, both specificity and accuracy deteriorated to be 55% and 76%. Using combination method with 201Tl-SPECT and biopsy, sensitivity, NPV and accuracy improved to be 84%, 70% and 85%. Based on its high PPV value, 201Tl-SPECT could be useful when biopsy method could not prove lung cancer or in case whose biopsy is considered to be invasive. Because of the lower NPV value owing to false negative cases in some adenocarcinoma, negative 201Tl-SPECT case should be followed up carefully.

Evaluation of absorption kinetics of orally administered theophylline in rats based on gastrointestinal transit monitoring by gamma scintigraphy

The gastrointestinal (GI) transit and absorption of orally administered theophylline, a highly absorbable drug without presystemic elimination, were investigated under fasted and fed conditions using three rats in a crossover study. To evaluate the GI transit rate for each segment in vivo, a noninvasive technique, gamma scintigraphy, was employed using a nonabsorbable compound, (99m)Tc-labeled diethylenetriamine pentaacetic acid (DTPA). Using a gamma scintigraphic technique it is possible to simultaneously evaluate the GI transit and absorption of orally administered drug in the same individual. Theophylline was simultaneously administered along with [(99m)Tc]DTPA to animals in the fasted and fed states. Each GI transit pattern, simulated using the GI transit-kinetic model with a lag time factor, was well fitted to the experimental data. Gastric emptying rate varied in each study, even under the same experimental condition. The GI transit pattern for each segment was highly variable, especially in animals in the fed state. This inconsistency in transit pattern was mainly due to the variability in gastric emptying, which was much slower in animals in the fed compared with the fasted state. However, in spite of a large variability of GI transit kinetics, the plasma concentration-time curves of theophylline were well predicted by the GI transit-absorption model using the individual GI transit parameters obtained in the study. The absorption rate of theophylline was considerably reduced in animals in the fed state, because of the reduction of gastric emptying rate. Analysis using GI transit-absorption model and gamma scintigraphic technique made it possible to estimate the variable absorption kinetics regulated by GI transit with huge variability.

Evaluation of absorption kinetics of orally administered theophylline in rats based on gastrointestinal transit monitoring by gamma scintigraphy

The gastrointestinal (GI) transit and absorption of orally administered theophylline, a highly absorbable drug without presystemic elimination, were investigated under fasted and fed conditions using three rats in a crossover study. To evaluate the GI transit rate for each segment in vivo, a noninvasive technique, gamma scintigraphy, was employed using a nonabsorbable compound, (99m)Tc-labeled diethylenetriamine pentaacetic acid (DTPA). Using a gamma scintigraphic technique it is possible to simultaneously evaluate the GI transit and absorption of orally administered drug in the same individual. Theophylline was simultaneously administered along with [(99m)Tc]DTPA to animals in the fasted and fed states. Each GI transit pattern, simulated using the GI transit-kinetic model with a lag time factor, was well fitted to the experimental data. Gastric emptying rate varied in each study, even under the same experimental condition. The GI transit pattern for each segment was highly variable, especially in animals in the fed state. This inconsistency in transit pattern was mainly due to the variability in gastric emptying, which was much slower in animals in the fed compared with the fasted state. However, in spite of a large variability of GI transit kinetics, the plasma concentration-time curves of theophylline were well predicted by the GI transit-absorption model using the individual GI transit parameters obtained in the study. The absorption rate of theophylline was considerably reduced in animals in the fed state, because of the reduction of gastric emptying rate. Analysis using GI transit-absorption model and gamma scintigraphic technique made it possible to estimate the variable absorption kinetics regulated by GI transit with huge variability.

[A new protocol of dual energy acquisition on stress 201Tl and rest 99mTc-tetrofosmin myocardial scintigraphy]

We carried out stress 201Tl (Tl) and rest 99mTc-tetrofosmin (TF) myocardial scintigraphy with dual energy acquisition in 24 patients with suspected ischemic heart disease performed coronary arteriography and elucidated the sensitivity of this method. One hour after light meal eating, TF (555 MBq) was injected intravenously at rest and after 3 minutes from injection of TF exercise or pharmacologic stress was performed. During stress Tl (111 MBq) was injected intravenously before end-point or at adequate point of pharmacologic stress. Dual energy acquisition using triple energy windows (TEW) was started after 5 minutes (early) and 4 hours (delayed) from stress. The sensitivity (Sn), specificity (Sp) and accuracy (Ac) in diagnosis of non-infarcted branches by using Tl (early)-TF (rest) and Tl (early)-Tl (delayed) were 79% vs. 53% (Sn), 78% vs. 96% (Sp) and 79% vs. 71% (Ac) respectively. Accordance of uptake score of infarcted region between TF (rest) and Tl (delayed) was 70%. In conclusion, this protocol is seemed to be useful as usual protocol for detection of myocardial ischemia and viability during about only 1 hour.

[Evaluation of technetium-99m-MIBI scintigraphy in metastatic differentiated thyroid cancer--comparison study with 131I and 201Tl]

Detectability of metastasis in differentiated thyroid cancer using technetium-99m-methoxyisobutyl isonitrile (99mTc-MIBI) was compared with that of 131I and 201Tl. Forty patients after total thyroidectomy were evaluated. The scan results were compared with those of 131I and 201Tl whole body scintigraphy per patient. The positive rate was 68% in 99mTc-MIBI, 84% in 131I, 60% in 201Tl respectively. As to the lymph node metastasis, the positive rates were 56% in 99mTc-MIBI, 78% in 131I, 39% in 201Tl. In lung metastasis, the positive rate was 46% in 99mTc-MIBI, 82% in 131I and 55% in 201Tl. Serum thyroglobulin (Tg) was significantly higher in 201Tl and/or 99mTc-MIBI positive group compared to that of negative group independent of 131I scan results. Although the detectability of both 99mTc-MIBI and 201Tl were inferior to that of 131I, 9 to 22% of metastasis were detected only by these radiopharmaceuticals. Both 99mTc-MIBI and 201Tl, therefore, should be used in cases with high serum Tg even with negative 131I uptake. Basing on the fact there was no prominent difference between 99mTc-MIBI and 201Tl in the detectability of metastasis, 99mTc-MIBI might be more suitable tracer because of better quality image.

A new radiopharmaceutical for the cerebral dopaminergic presynaptic function: 6-radioiodinated L-meta-tyrosine

Geometric isomers of radioiodinated L-meta-tyrosine, 6-[I-125]iodo-and 4-[1-125]iodo-L-meta-tyrosine (6-I-L-mTyr, 4-I-L-mTyr) were separated by high-performance liquid chromatography . Both 6-I- and 4-I-L-mTyr had high energy-dependent brain accumulation. 6-I- and 4-I-L-mTyr were also metabolically stable and were rapidly excreted through the urine. 6-I-L-mTyr had a predilection for the cerebral aromatic L-amino acid decarboxylase (DOPA decarboxylase), the final enzyme of dopamine biosynthesis. 6-Radioiodinated L-mTyr is a new radiopharmaceutical that can be both useful in assessing cerebral amino acid transport mechanism and quantifying metabolically active DOPA decarboxylase.

rCBF in neurodegenerative diseases as estimated by the autoradiographic (ARG) method and delayed I-123-IMP studies

A total of 24 patients with a mean age of 45.8 +/- 20.8 were included in the study. The patients were grouped as Control (C), Degenerative Syndromes (DS), Degeneration Associated with External Factors (DEF), Degeneration Associated with Focal Neurologic Lesion (DFN) and Demyelinating Disease (DM). Imaging started 15 minutes for early and 4 hours for delayed scans after i.v. infusion of I-123 IMP. The rCBF was calculated by the IMP autoradiographic (ARG) method. The wash-out ratio (WR) was calculated as the ratio of the Delay/Early count. In the rCBF of the various areas of the brain, significant differences were noted between various disease groups. No correlation was noted between rCBF and WR (r = -0.50). The WR of patients grouped according to various disease processes did not show a significant difference between various areas of the brain. In conclusion, the rCBF was effective in separating both various areas of the brain and disease entities. WR from a delayed study is less useful in neurodegenerative diseases.

Retention of Tc-99m ECD in delayed SPECT of the brain

We determined the effect of retention on the changes in regional biodistribution of Tc-99m ECD in the brain. A total of 14 cases, 7 normal volunteers and 7 patients with various diagnoses but with very minimal radiologic findings or none were included in the study. SPECT images were taken at 30 min, 1, 2, 3, 4 and 6 hrs after an intravenous injection. Retention rates were calculated in various regions and were corrected according to the time decay of technetium. There was a tendency for the retention rate to increase up to three hours of imaging and then a decrease was noted in most regions of the brain. In the thalamus, increasing retention was noted. In conclusion, Tc-99m ECD retention in the different regions of the brain varies with time. These differences should always be considered when planning and interpreting SPECT quantitative studies.

Brain uptake of iodinated L-meta-tyrosine, a metabolically stable amino acid derivative

The possibility of using L-meta-tyrosine (L-mTyr) with high metabolic stability and amino acid transport affinity was evaluated. mTyr was first separated into D- and L-isomers with high-performance liquid chromatography and both were labelled with non-carrier-mediated 125I. Biodistribution and pharmacological studies of radioiodinated mTyr in mice and rats were then performed. 125I-L-mTyr showed greater accumulation in the brain and the pancreas. It accumulated in the brain stereospecifically in the in vivo studies and by the L-tyrosine competitive energy dependent transport system in the in vitro studies. It was resistant to deiodination, appeared to have no retention mechanism and was rapidly excreted. 123I-L-mTyr has the potential of an amino acid transport marker, especially in the brain and the pancreas.

123I-MIBG myocardial scintigraphy in diabetic patients: relationship with 201Tl uptake and cardiac autonomic function

PURPOSE

To investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by 201Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with non-insulin-dependent diabetes mellitus (NIDDM).

SUBJECTS AND METHODS

Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after 123I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of 123I-MIBG (WR) were obtained from both planar images. On SPECT images, the total uptake score (TUS) was obtained by the 5 point score method by dividing the myocardium into 20 segments on visual analysis. Similarly, the difference between the 201Tl image and the 123I-MIBG image in TUS was taken as the difference in the total uptake score (delta TUS) representing cardiac sympathetic denervation without SMD.

RESULTS

On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding delta TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for delta TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus.

CONCLUSION

123I-MIBG myocardial uptake is affected by both SMD and cardiac autonomic neuropathy. Based on the finding that delta TUS was much higher in AN [+] subgroups and there was no statistically significant difference between SMD [+] AN [+] and SMD [-] AN [+] subgroups, a decrease in myocardial 123I-MIBG uptake might progress independently of SMD.

Computer-Aided Diagnosis (CAD) for Mammography: Preliminary Results

PURPOSE: To evaluate the CAD system for screening mammograms. MATERIALS AND METHODS: Mammograms of patients with asymptomatic breast cancerwere examined retrospectively. A total of 260 screening mammograms from 65 patients (bilateral cranio-caudal and medio-lateral-oblique views from each) were tested by using the CAD system (ImageChecker M1000 system, R2 Technology, Los Altos, CA, USA). Results: With 0.58 microcalcifications marks/film and 0.20 mass marks/film set as the false positive rate, 100% of microcalcifications cases and 79% of mass cases were detected correctly. Conclusion: The CAD system has the potential to become a second reader. Further developments are expected to improve the accuracy of detection of mass lesions

Gallium-67 scintigraphy in the treatment and prognosis of acute adult T-cell lymphoma

The case of a 77-year-old male patient who complained of left upper quadrant pain and progressive vomiting. Laboratory examination showed extremely high lactic acid dehydrogenase (LDH) and adult T-cell leukemia antibody (ATLA). The anatomical studies CT, MRI, US and upper GI series substantiated an omental lymphadenopathy which was causing a circumferential compression of portions of the duodenum and jejunum. Gallium-67 citrate (Ga-67) scintigraphy showed high uptake at LUQ. Ultrasound guided biopsy failed to confirm the diagnosis. Irradiation was performed. Ga-67 scintigraphy had a contributory role in clinical subtyping of the disease, planning of treatment, posttreatment assessment and prognostication of adult T-cell lymphoma.

Relationship between extraosseous accumulation in bone scintigraphy with 99Tcm-HMDP and histopathology

We assessed the relationship between 99Tcm-HMDP extraosseous accumulation (EOA), the histopathology of primary lesions and various laboratory findings. In 155 of 4824 patients, 163 EOA were noted. Of these, 33.7% were in the abdomen, 27.6% in the chest, 22.7% in the extremities, 9.8% in the pelvic area and 6.1% in the head and neck area. We found that 72.4% of EOA were due to malignant processes and 27.6% to benign processes. In the abdomen, 36.6% of the EOA were due to hepatocellular carcinoma and intestinal carcinoma. In the chest, 46.7% of EOA were a result of breast carcinoma. In the extremities, 28.7% of the EOA were due to sarcoma. The mean white blood cell count was elevated (8.0 +/- 6.3 x 10(3)) in patients with malignant processes. The mean serum haemoglobin and haematocrit in benign and malignant processes, for both males and females, were below normal values. All other laboratory findings were within normal limits. Significant differences in serum haemoglobin and haematocrit were noted between male and female patients with benign processes (P = 0.04 and P = 0.04, respectively). No other significant differences between benign and malignant processes were noted. Therefore, EOA is more frequently associated with malignant processes of primary lesions and is often accompanied by leukocytosis and anaemia.

Application of SPET using technetium-99m sestamibi in brain tumours and comparison with expression of the MDR-1 gene: is it possible to predict the response to chemotherapy in patients with gliomas by means of 99mTc-sestamibi SPET?

Technetium-99m sestamibi (MIBI) is thought to be passively taken up by metabolically active tumour cells and effluxed from them by P-glycoprotein (Pgp). This 170-kDa membrane-bound protein, encoded by the MDR-1 gene, acts as an energy-dependent efflux pump for several antineoplastic agents, resulting in multidrug resistance. For this reason, it is of interest whether the tumour's response to chemotherapy can be predicted by MIBI single-photon emission tomography (SPET). In this study, MIBI SPET was compared with thallium-201 (Tl) SPET using magnetic resonance imaging as a guide in 16 patients with untreated brain tumours [ten glioblastomas (GBs), two anaplastic astrocytomas (AAs), two low-grade gliomas (LGASs) and two metastatic brain tumours) and in four patients who had received treatment for with brain tumours (two GBs, two AAs). In addition, we investigated the expression of the MDR-1 gene and its product Pgp in the same patients, and compared the results with MIBI SPET findings. MIBI, as well as Tl, was highly accumulated and retained in the enhanced region of malignant gliomas. In addition, MIBI SPET yielded sharp and well-contrasted images, and the margin of the tumour was more clearly defined than with Tl SPET due to a good signal-to-noise ratio. Follow-up MIBI SPET in patients who had received therapy showed marked uptake in a patient with malignant transformation, who deteriorated clinically. Patients with no uptake on MIBI SPET showed no sign of recurrence. Semiquantitative analysis of untreated patients showed a relationship between the early uptake index (UI, ratio of average count/pixel in the lesion to that in the contralateral area on early images) and the degree of malignancy (early UI = 1.08+/-0.06 in LGASs, 4.10+/-0.84 in AAs, 5.71+/-3.47 in GBs, and 7.52+/-1.52 in metastatic brain tumours). The retention index (RI, ratio of delayed to early UI) of MIBI was significantly lower than that of Tl in metastatic brain tumours (P<0.05), but not in malignant gliomas. Histological and biological investigation of gliomas showed that the MDR-1 gene and its product Pgp were expressed only in normal endothelial cells and not in tumour cells or proliferating endothelial cells; Pgp tended to decrease as the degree of malignancy rose. Hence, the presence of Pgp and the grade of malignancy were inversely related in gliomas. By contrast, immunohistochemical study showed strong accumulation of Pgp in metastatic brain tumour cells. These histopathological findings and MIBI SPET findings are compatible with experimental data; MIBI was washed out by Pgp. The main cause of chemoresistance is probably not an increasing drug efflux by Pgp in gliomas. Thus, MIBI SPET is useful for detecting the active lesions, but may not be useful for predicting the response to chemotherapy in gliomas.

[Evaluation of brain tumor by 99mTc-MIBI: comparison study with 201Tl and predictivity of therapeutic effect]

We compared the detectability of 99mTc-MIBI and 201Tl-chloride for brain tumor in relationship with histopathology. We also evaluated correlation between therapeutic effect using ACNU, Cisplatine and the degree of MIBI tumor uptake. The subjects were 31 brain tumor histologically confirmed by operation or biopsy. Dual-isotope SPECT technique was performed at both 20 min and 180 min after tracer injection. A tumor to normal lung ratio on both early (ER) and delayed image (DR) and retention index (RI) were calculated. The positive rates of 99mTc-MIBI (90.3% and 77.4%) were comparable to that of 201Tl (90.3% and 80.6%). In the relationship with histopathology, both MIBI and Tl accumulated in 100% of glioblastoma (GBM), metastasis (meta), anaplastic astrocytoma and 25% of low grade astrocytoma on both early and delayed images. On semiquantitative analysis, there were no statistical significance among GBM, meta and anaplastic astrocytoma of ER, DR, RI in the both radiopharmaceuticals. However, both ER and DR in GBM tended to be higher than those of anaplastic astrocytoma. In spite of intense MIBI uptake, GBM patients died within six months except one patient. We concluded that MIBI can be helpful in detecting brain tumor as Tl. MIBI also might be useful in estimating the degree of malignancy in glioma. However, intense MIBI uptake did not mean favorable therapeutic effect in patients with GBM treated with ACNU and Cisplatine.

[123I-MIBG lung uptake in patients with diabetes mellitus]

The purpose of this study is to clarify the relationship between 123I-MIBG lung uptake and silent myocardial ischemia (SMI), cardiac autonomic neuropathy (AN) or clinical characteristics. For the quantitative analysis, lung to upper mediastinum uptake ratio (L/M) and heart to upper mediastinum uptake ratio (H/M) were obtained from chest planar image. In addition, both lung washout ratio (%WR-L) and heart washout ratio (%WR-H) were calculated from early and delayed images. Each indices were compared in both diabetic and control groups. Mean values of H/M in diabetes with complication were significantly lower than those of control group. Particularly, AN(+)SMI(+) group showed lowest value. Similarly, mean values of %WR-H in diabetes with complication were significantly higher than those of control group and AN(+)SMI(+) group showed highest value. Although mean value of L/M in each diabetic group was significantly higher than that of control group, there was no statistical significance among each diabetes except AN(+)SMI(-) group on early image. Mean value of %WR-L in AN(+) or SMI(+) group was also significantly higher than that of control group, but there was no statistical significance among each diabetic group. The current study suggested that high pulmonary 123I-MIBG uptake in diabetes was independent of the complication of SMI or AN. Pulmonary endothelial dysfunction related with severity of diabetes mellitus was considered to be the most important factor.

Acetazolamide challenge and technetium-99m-ECD versus iodine-123-IMP SPECT in chronic occlusive cerebrovascular disease

We compared the acetazolamide challenge test using 99mTc-ECD SPECT and 123I-IMP SPECT images in patients with chronic occlusive cerebrovascular disease. We also evaluated the usefulness of linearization correction for acetazolamide challenge test of 99mTc-ECD SPECT.

METHODS

Twenty patients with unilateral chronic occlusive cerebrovascular disease (10 patients had middle cerebral arterial lesion and 10 had internal carotid lesion) were included in the study. Split-dose (a dose fractioning was 1:2), and sequential SPECT technique was used for 99mTc-ECD SPECT studies while only acetazolamide challenge test studies for 123I-IMP SPECT were performed. Permeability surface area product model (PS model) and back-diffusion model (Lassen's correction) were used for linearization correction of acetazolamide challenge with 99mTc-ECD SPECT.

RESULTS

Six of 16 patients with reduced vasodilatory capacity in 123I-IMP SPECT were underestimated by 99mTc-ECD SPECT acetazolamide challenge test. Relative ECD uptake normalized by cerebellar uptake compared with IMP uptake showed a nonlinear relationship, indicating relatively less uptake in high flow range. The underestimations of limited vasodilatory capacity observed in 99mTc-ECD SPECT without linearization correction was modified by linearization algorithm. However, the effect of correction based on PS model was superior than that of Lassen's correction. The corrected 99mTc-ECD uptake ratio, based on PS model, and IMP uptake ratio demonstrated a better linear relationship than that of Lassen's correction.

CONCLUSION

Technetium-99m ECD SPECT corrected based on the PS model is a better method of linearization for evaluating cerebrovascular reserve using acetazolamide challenge.