Hisashi Bunko

Quantitative analysis of 123I-metaiodobenzylguanidine (MIBG) uptake in hypertrophic cardiomyopathy

Myocardial scintigraphy with 123I-meta-iodobenzylguanidine (MIBG) and thallium-201 (201Tl) was performed in 29 patients with hypertrophic cardiomyopathy (HCM) using whole-body scintigraphy and single-photon emission computed tomography (SPECT). Nonhypertensive patients were classified into three groups according to the septal thickness determined by ultrasonography; group 1 (wall thickness less than 16 mm, n = 5), group 2 (from 16 to 20 mm, n = 12) and group 3 (greater than 20 mm, n = 4). The regional myocardial uptakes of both 201Tl and 123I-MIBG (percent of injected dose/cm3 myocardium) were higher in the more hypertrophic septa. However, when regional MIBG uptake at 3 hours was divided by the 201Tl uptake to calculate the MIBG uptake per unit of blood flow, the hypertrophic septa showed lower mean values--0.39 +/- 0.23 and 0.50 +/- 0.10 in groups 3 and 2, respectively (p less than 0.1 compared with 0.69 +/- 0.20 in group 1). The regional MIBG clearance rate in the septum was significantly higher in group 3 compared with group 1 (13.4 +/- 8.0%/hr versus 1.5 +/- 6.2%/hr, p less than 0.05). The uptake and 123I-MIBG clearance rate in the lateral wall showed a similar tendency. Myocardial uptake determined by whole-body scintigraphy was slightly increased in group 2 (3.5 +/- 0.6%, p less than 0.05) compared with group 1 (2.7 +/- 0.8%); however, it was lower in group 3 (2.7 +/- 0.4%). Myocardial 123I-MIBG distribution demonstrated various patterns in comparison with 201Tl distribution, suggesting that flow-independent changes in sympathetic innervation or activity may exist in patients with HCM.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical application of /sup 201/Tl scintigraphy in patients with cold thyroid nodules

201TI-chloride scintigraphy was performed in 45 patients with cold thyroid nodules. The 201TI scintigram was positive in 17 of 18 thyroid patients with cancer (94.4%), 8 of 20 patients with an ademoma (40.0%), 1 of 2 adenomatous goiter patients (50.0%), and all of 5 cases of chronic thyroiditis (100.0%). When the cold nodule was demonstrated to be positive with 201TI, the statistical chance of the lesion being a cellular one was 100.0% and a risk of its malignancy was 54.8%. On the other hand, the nodule with negative 201TI concentration had a 14.3% chance of cellularity and a 7.1% risk of malignancy. Thus, 201TI scintigraphy is of use in the differential diagnosis of the cold thyroid nodule.

Impairment of regional fatty acid uptake in relation to wall motion and thallium-201 uptake in ischaemic but viable myocardium: Assessment with iodine-123-labelled beta-methyl-branched fatty acid

In coronary artery disease, discrepancy in the uptake of thallium-201 and of methyl-branched fatty acid at rest has been described. The purpose of this study was to evaluate iodine-123 labelled beta-methylbranched fatty acid (BMIPP) myocardial uptake and wall motion at rest in segments with stress-induced ischaemia identified by stress201Tl tomography in patients with chronic coronary artery disease.123I-BMIPP myocardial tomography was performed at rest and was compared with the findings of exercise-reinjection201Tl tomography in 45 patients with chronic coronary artery disease. Regional wall motion was evaluated by contrast left ventriculography in 36 patients. Among 237 segments with reversible201Tl defects, equally decreased uptake on both reinjection201Tl and BMIPP images was observed in 93 (39%), more severely decreased uptake of BMIPP in 118 (50%) and more severely decreased uptake of reinjection201Tl in 26 (11%). On the other hand, among 90 segments with non-reversible201Tl defects, each pattern was observed in 71 (79%), 6 (7%) and 13 (14%) segments, respectively. When comparing the ischaemic segments with and without more severely reduced uptake of BMIPP than of reinjection201Tl, wall motion was impaired to a greater extent in the segments with more severely reduced uptake of BMIPP than of reinjection201Tl [severe hypo- or dyskinesis was present in 64 (70%) of 91 segments and in 24 (22%) of 110 segments, respectively,P<0.005]. In patients with chronic coronary artery disease, resting fatty acid uptake was frequently more reduced than reinjection201Tl in the segments with stress-induced ischaemia, while in most of the fixed perfusion defects BMIPP and reinjection201Tl uptake decreased concordantly. In ischaemic myocardium, wall motion was impaired to a greater extent in those segments which showed more severely reduced uptake of BMIPP than of reinjection201Tl. In ischaemic but viable myocardium, discordant BMIPP uptake less than reinjection201Tl uptake may indicate metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities. In conclusion, the combination of resting BMIPP and stress-reinjection201Tl imaging may provide information on metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities.

Nuclear tomographic phase analysis: Localization of accessory conduction pathway in patients with Wolff-Parkinson-White syndrome

The purpose of this study was to evaluate the usefulness of tomographic phase analysis in detecting the site of the accessory conduction pathway (ACP) in patients with Wolff-Parkinson-White (WPW) syndrome. Gated emission computed tomography and planar gated blood pool scintigraphy were performed in 20 patients with WPW syndrome, 14 with delta waves and six without delta waves (two intermittent types and four concealed types). The abnormal initial contractions in both planar and tomographic phase images were compared with the sites of ACPs confirmed by epicardial mapping and surgery. The atrioventricular ring was divided into eight segments on each side, and the identification of the initial phase in the segment in which the ACP was located, or that adjacent to it, was considered to be the correct diagnosis. In planar phase analysis, the abnormal initial phase was identified correctly in 8 of 14 patients (57%), whereas in tomographic phase analysis, the site of the ACP was detected in 12 of 14 patients (86%). Tomographic phase analysis can be a helpful adjunctive method in patients with WPW syndrome.

Cardiac sarcoidosis demonstrated by Tl-201 and Ga-67 SPECT imaging.

Ga-67 and TI-201 SPECT was performed to evaluate cardiac sarcoidosis in a 15-year-old boy. TI-201 SPECT imaging showed decreased uptake in the inferior to lateral wall and Ga-67 accumulation in the area of decreased TI-201 uptake. These findings suggested cardiac sarcoidosis, and cardiac biopsy confirmed this diagnosis. After corticosteroid therapy, myocardial uptake of Ga-67 disappeared and myocardial TI-201 uptake became more homogeneous.

Error of uptake in dual energy acquisition with201TI and123I labeled radiopharmaceuticals

In myocardial scintigraphy, simultaneous injection of two radionuclides and dual energy acquisition are potentially useful in the assessment of regional perfusion and metabolism. The feasibility of dual radionuclide study with201TI and123I labeled radiopharmaceuticals (meta-iodobenzylguanidine I 123, in this study) was investigated in phantoms and patients. The crosstalk of one radionuclide to the other pulse height window was defined as the ratio of the201T1 count in the123I and201T1 windows, R[I/Tl], and the ratio of the123I count in the201TI and123I windows, R[Tl/I]. The ratios were determined in planar images and SPECT studies. In clinical studies with whole body scintigraphy (n = 8), the value of R differed significantly in various organs. In the SPECT study (n =13), R was not uniform and varied with time and location, resulting in significant errors in uptake and regional count ratio. Thus, dual energy acquisition with201TI and 1231 labeled radiopharmaceuticals is generally not recommended because of varying amounts of crosstalk interference. Possible solutions to this problem are discussed. The feasibility of dual radionuclide study must be confirmed in human as well as in phantom studies.

Intraperitoneal radioimmunotherapy in treating peritoneal carcinomatosis of colon cancer in mice compared with systemic radioimmunotherapy

Peritoneal spread is one of major causes of mortality in colorectal cancer patients. In the current investigation, the efficacy of radioimmunotherapy (RIT) with i.p. administration of an anti‐colorectal cancer IgG1,131I‐A7, was compared to that with i.v. administration in BALB/c female mice bearing peritoneal nodules of LS180 human colon cancer cells, at the same toxicity level. Distribution of either i.p. or i.v. administered 131I‐A7 and i.p. administered irrelevant 131I‐HPMS‐1 was assessed. Based on the results of toxicity determination at increments of 2 MBq and estimated dosimetry, an i.p. dose of 11 MBq and an i.v. dose of 9 MBq were chosen for treatment. Mice were monitored for long‐term survival: untreated mice (n=11), mice undergoing i.p. RIT with 131I‐A7 (n=11), mice undergoing i.v. RIT with 131I‐A7 (n=11) and mice undergoing non‐specific i.p. RIT with 131I‐HPMS‐1 (n=5). Intraperitoneal injection of 131I‐A7 produced faster and greater tumor accumulation than i.v. injection: 34.2±16.5% of the injected dose per g (% ID/ g) and 11.1±3.6% ID/g at 2 h, respectively (P<0.0001). Consequently, cumulative radioactivity in tumors was 1.73‐fold higher with i.p. injection. 131I‐HPMS‐1 did not show specific accumulation. Non‐specific RIT with 131I‐HPMS‐1 (mean survival, 26.0±2.5 days) did not affect the survival as compared to no treatment (26.7±1.9 days). Intravenous RIT with 131I‐A7 prolonged the survival of mice to 32.8±1.8 days (P<0.01). Intraperitoneal RIT with 131I‐A7 improved the survival more significantly and attained cure in 2 of 11 mice (P<0.05 vs. i.v. RIT). In conclusion, i.p. RIT is more beneficial in treating peritoneal carcinomatosis of colon cancer than i.v. RIT in a murine model.

123I-labelled BMIPP fatty acid myocardial scintigraphy in patients with hypertropic cardiomyopathy: SPECT comparison with stress 201Tl.

123I-labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) was performed in 17 patients with hypertrophic cardiomyopathy, and was compared with 201Tl exercise stress myocardial perfusion SPECT images. Fourteen patients showed asymmetrical hypertrophy, and three demonstrated apical hypertrophy. SPECT was performed 20 min and 3 h after injection of 111 MBq 123I-BMIPP at rest. Exercise stress 201Tl SPECT was performed at 10 min and 3 h after injection and was compared with BMIPP imaging. In 13 patients BMIPP accumulation in the hypertrophied area in the 20 min image was lower than that of 3 h 201Tl uptake. Interestingly, six patients demonstrated 201Tl redistribution in the region where the uncoupling of BMIPP uptake at 20 min and 201Tl accumulation at 3 h after exercise was observed. These findings suggest that impaired fatty acid metabolism or utilization in hypertrophic myocardium and ischaemia or impaired coronary flow reserve may be one of the causes of the abnormality of fatty acid accumulation.

Voluntary Medication Error Reporting Program in a Japanese National University Hospital

BACKGROUND: In Japan, as in other countries, medical accidents arising from human error can seriously damage public confidence in medical services, as well as being intrinsically undesirable. OBJECTIVE: Errors voluntarily reported by the healthcare practitioners in our institution (Kanazawa University Hospital) were considered to assess the contributory factors by using the accumulated error database in the hospital information system. METHODS: Medical errors in our institution during the period from July 1, 2000, to June 30, 2002, were counted using the error reporting system database and were classified. RESULTS: The number of errors reported during the investigation period was 1378, of which 78% were reported by nursing staff. Medication errors involving administration of injectable or oral drugs to inpatients, dispensing, and prescription accounted for about 50% of that number. Among dispensing errors, 53% were detected by patients or their families and 36% by nurses. CONCLUSIONS: The best method of error prevention is to learn from previous errors. For this purpose, the error reporting program is effective. In patient safety management, it is important to take into account the potential risks of future errors, as well as to capture information about errors that have already happened. For safety management, adoption of appropriate information technology (e.g., implementation of a prescription order entry system) is effective in reducing medication errors. However, it is important to note that serious errors can also arise in computer-based systems.

Myocardial scintigraphic study with 123I 15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid in patients with hypertrophic cardiomyopathy

123I 15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid (BMIPP) myocardial scintigraphy and exercise stress thallium (TI)-201 myocardial scintigraphy were performed in 17 patients with hypertrophic cardiomyopathy (HCM) to evaluate the existence of abnormal fatty acid metabolism in the myocardium and the relationship between this abnormality and myocardial ischemia. On the BMIPP scintigraphy, abnormalities were found in 12 of 17 patients (71%). Five patients showing no abnormalities on the BMIPP scintigraphy had well preserved exercise tolerance and had longer exercise duration than the others showing BMIPP scintigraphic abnormalities (P < 0.001). On the evaluation of the segmental abnormalities, TI scintigraphic abnormalities were found in 15 (50%) of 30 segments showing decreased accumulation of BMIPP. On the other hand, BMIPP scintigraphic abnormalities were found in all segments showing decreased accumulation of TI. The sites of decreased accumulation of BMIPP and TI were in good agreement with the sites of wall hypertrophy. Four patients showing BMIPP scintigraphic abnormalities and no T1 scintigraphic abnormalities were in higher New York Heart Association functional classes, had shorter exercise duration (P < 0.05) than the 5 patients showing no abnormalities on either scintigraphy. It is concluded that abnormalities of fatty acid metabolism in the heart are detected at a high rate in patients with HCM, and may be due in part to factors other than myocardial perfusion disturbance.