Simultaneous acquisition of iodine-123 emission and technetium-99m transmission data for quantitative brain single-photon emission tomographic imaging

The aim of this study was to obtain quantitative iodine-123 brain single-photon emission tomographic (SPET) images with scatter and attenuation correction. We used a triple-headed SPET gamma camera system equipped with fan-beam collimators with a technetium-99m line transmission source placed at one of the focal lines of the fan-beam collimators. Four energy windows were employed for data acquisition: (a) 126–132 keV, (b) 132–143 keV, (c) 143–175 keV and (d) 175–186 keV. A simultaneous transmission-emission computed tomography scan (TCT-ECT) was carried out for a brain phantom containing ¹²³I solution. The triple energy window scatter correction was applied to the ¹²³I ECT data measured by means of the windows (b), (c) and (d) acquired by two detectors. Attenuation maps were reconstructed from ^99mTc TCT data measured by means of the windows (a), (b) and (c) acquired by one detector. Chang’s iterative attenuation correction method using the attenuation maps was applied to the ¹²³I ECT images. In the phantom study cross-calibrated SPET values obtained with the simultaneous mode were almost equal to those obtained with the sequential mode, and they were close to the true value, within an error range of 5.5%. In the human study corrected images showed a higher grey-to-white matter count ratio and relatively higher uptake in the cerebellum, basal ganglia and thalamus than uncorrected images. We conclude that this correction method provides improved quantification and quality of SPET images and that the method is clinically practical because it requires only a single scan with a ^99mTc external source. Received 6 June and in revised form 27 July 1998     

Hepatectomy based on the tumor hemodynamics for hepatocellular carcinoma: a comparison among the hybrid and pure laparoscopic procedures and open surgery

Purpose

This study was designed to evaluate the surgical parameters and treatment outcomes of tumor hemodynamics-based pure laparoscopic (PURE) and laparoscopy-assisted (HYBRID) hepatectomy for small hepatocellular carcinoma (HCC) compared with those of open hepatectomy.

Methods

Using a prospectively collected database from 1997 to 2011, we analyzed the data of 56 consecutive cases of laparoscopic hepatectomy for HCC (PURE, n = 24; HYBRID, n = 29; HALS, n = 3) from among 102 cases undergoing laparoscopic hepatectomy. We employed 27 cases treated by open hepatectomy during the same period as controls.

Results

PURE was associated with lesser blood loss, lower weight of the resected liver, and a shorter skin incision than HYBRID and open hepatectomy [median blood loss (mL): PURE 7, HYBRID 380, Open 450; P < 0.05]. On the other hand, HYBRID hepatectomy was associated with a longer operation time [operation time (min): HYBRID 232, Open 185; P = 0.0226]. The length of hospitalization in the cases treated by PURE and HYBRID hepatectomy was shorter than that in the cases treated by open hepatectomy [length of hospitalization (days): PURE 11, HYBRID 12, Open 17; P < 0.05]. One case each of transfusion and morbidity was recorded in this series. There was no significant difference of the overall (OS) or disease-free survival (DFS) between the patients treated by laparoscopic and open hepatectomy (3-year OS: 100 vs. 100 %; DFS 50 vs. 62 %, respectively).

Conclusions

Neither the surgical parameters nor the treatment outcomes of hemodynamics-based laparoscopic hepatectomy were inferior to those of open hepatectomy.     

Clinical significance of exercise-induced ST segment depression in patients with lateral myocardial infarction involving the left circumflex artery: evaluation by exercise 99mTc-MIBI myocardial scintigraphy

PURPOSE: The aim of this study is to clarify the causes of exercise-induced ST-segment depression in patients with broad lateral old myocardial infraction involving LCX (LCX-OMI) without ischemia on exercise scintigraphy. METHOD: Twenty one patients (M/F = 11/10, age = 62 +/- 19 years) with myocardial infraction involving LCX (LCX-MI), but without fill-in on exercise and rest MIBI quantitative gated SPECT (QGS), were selected. They were divided into two groups of Group ST(+) (n = 11, with significant ST depression (max -2.8 +/- 0.4 mm), Group ST(-) (n = 10) without ST depression. On 20 SPECT segments of both exercise and rest SPECT, we scored uptake score as DS (0 = normal to 3 = defect) and wall motion as WMS (0 = normal to -5 = dyskinesis) and summed DS (TDS) and WMS (TWMS) in LCX region, furthermore, calculated the difference of TWMS (delta TWMS [exercise-rest]), end diastolic volume (EDV) and ejection fraction (EF) during exercise were compared between the two groups. RESULT: Group ST(+) showed significantly (p < 0.01) lower EF (35.4 +/- 9.2% vs. 60.2 +/- 6.2%), larger EDV (146 +/- 53 ml vs. 93 +/- 15 ml), higher TDS (5 vs. 7 +/- 3), lower TWMS (-25 +/- 9 vs. -6 +/- 5), furthermore lower delta TWMS (-6.9 +/- 4.0 vs. -2.0 +/- 0.8) than Group ST(-). CONCLUSION: Exercise-induced significant ST depression in V2-4 without ischema in LCX-MI was observed in patients with broad LCX-MI, low EF, and was related to impaired wall motion in LCX region. ST depression in V2-4 was considered to appear as miller image of ST elevation at postero-inferior wall due to disturbed wall motion on exercise.     

Transcatheter embolization of an aortobronchial fistula with N-butyl cyanoacrylate

Aortobronchial fistula is a fatal complication after thoracic aortic surgery. So far, treatment options for aortobronchial fistula have included surgical and endovascular stent-graft methods. Herein, a case of an aortobronchial fistula with life-threatening hemoptysis managed with transcatheter embolization of the fistula with N-butyl cyanoacrylate is reported. For the patient with an aortobronchial fistula who cannot be treated by surgical or endovascular stent-graft methods, transcatheter embolization of the fistula may be the only available life-saving method.     

Correction of nonuniform attenuation and image fusion in SPECT imaging by means of separate X-ray CT

Improvements in image quality and quantitation measurement, and the addition of detailed anatomical structures are important topics for single-photon emission tomography (SPECT). The goal of this study was to develop a practical system enabling both nonuniform attenuation correction and image fusion of SPECT images by means of high-performance X-ray computed tomography (CT). A SPECT system and a helical X-ray CT system were placed next to each other and linked with Ethernet. To avoid positional differences between the SPECT and X-ray CT studies, identical flat patient tables were used for both scans; body distortion was minimized with laser beams from the upper and lateral directions to detect the position of the skin surface. For the raw projection data of SPECT, a scatter correction was performed with the triple energy window method. Image fusion of the X-ray CT and SPECT images was performed automatically by auto-registration of fiducial markers attached to the skin surface. After registration of the X-ray CT and SPECT images, an X-ray CT-derived attenuation map was created with the calibration curve for 99mTc. The SPECT images were then reconstructed with scatter and attenuation correction by means of a maximum likelihood expectation maximization algorithm. This system was evaluated in torso and cylindlical phantoms and in 4 patients referred for myocardial SPECT imaging with Tc-99m tetrofosmin. In the torso phantom study, the SPECT and X-ray CT images overlapped exactly on the computer display. After scatter and attenuation correction, the artifactual activity reduction in the inferior wall of the myocardium improved. Conversely, the incresed activity around the torso surface and the lungs was reduced. In the abdomen, the liver activity, which was originally uniform, had recovered after scatter and attenuation correction processing. The clinical study also showed good overlapping of cardiac and skin surface outlines on the fused SPECT and X-ray CT images. The effectiveness of the scatter and attenuation correction process was similar to that observed in the phantom study. Because the total time required for computer processing was less than 10 minutes, this method of attenuation correction and image fusion for SPECT images is expected to become popular in clinical practice.     

Pulmonary metastases from uterine malignancies: results of surgical resection in 133 patients

OBJECTIVE: The long-term results of the surgical treatment for patients with pulmonary metastases from uterine malignancies were clarified. METHODS: A total of 133 patients who underwent pulmonary metastasectomy for uterine malignancies were enrolled in the Metastatic Lung Tumor Study Group of Japan between March 1984 and February 2002. These patients constituted the study population, and their clinical, pathologic, and prognostic data were retrospectively analyzed. RESULTS: The morbidity and mortality rates related to the operation were minimal (1% and 1%, respectively). The 5- and 10-year survivals after the surgical resection in all cases were 54.6% and 44.9%, respectively. The 5-year survivals for each histologic type were estimated to be 46.8% for squamous cell carcinoma (n = 58), 40.3% for cervical adenocarcinoma (n = 13), 75.7% for endometrial adenocarcinoma (n = 23), 86.5% for choriocarcinoma (n = 16), and 37.9% for leiomyosarcoma (n = 11). In the univariate analysis, the following were shown to be associated with poor survival: primary tumor in the cervix, short disease-free interval (<12 months), large number of resected metastases (> or =4), and large tumor size (> or =3 cm). After mutual adjustment, short disease-free interval (<12 months) alone was related to risk of death (hazard ratio = 2.26, 95% confidence interval = 1.06-4.78) for 105 patients, excluding patients with choriocarcinoma and miscellaneous histologic types. CONCLUSION: Pulmonary metastasectomy for uterine malignancies is a safe and acceptable treatment to improve survival. Patients with a disease-free interval of 12 months or more are good candidates for this treatment if there is adequate control of the primary tumor without extrapulmonary metastasis.