Examination for quantitative evaluation of abnormality of regional pulmonary blood flow in patients with diffuse pulmonary diseases--an application of bull's eye analysis

Bull's eye analysis was applied to the 99mTc-MAA lung perfusion scintigraphy (planar or SPECT). Three kind of phantoms were used to examine spatial and density resolution. Filling defect of 3 cm in diameter was detected and 30% difference between one RI concentration and the other was also detected by this method. 99mTc-MAA lung perfusion scintigraphy was performed in 39, including 28 with diffuse pulmonary diseases and 11 normal subjects. Bull's eye image with its circumferential profile curve was compared visually with conventional planar or SPECT image. This method was superior or equal to conventional image in 78% (planar) and in 75% (SPECT). Especially in patients with interstitial pneumonia, 94% was superior or equal. The patient's Bull's eye map was compared with the lower limit of normal (mean-2SD), and the extent score (ES) and the severity score (SS) were calculated. The changes of ES and SS was useful to follow up the clinical course of the patients. This method would be effective to evaluate the regional pulmonary blood flow quantitatively.     

Comparison of observer reliability in assessing alveolar bone changes from color-coded with subtraction radiographs

OBJECTIVES: To assess intra- and interobserver agreement on marginal changes in periodontal bone from color-coded compared with subtraction radiographs. METHODS: Sequential radiographs from patients undergoing periodontal treatment were acquired using direct digital intra-oral radiography. Fifty-one pairs of color-coded and subtraction radiographs were produced and evaluated twice by six dentists for changes in marginal bone. Intra- and interobserver agreement were calculated. RESULTS: Intra-observer agreement was significantly higher for the color-coded radiographs (P < 0.05). Interobserver agreement was significantly higher for color-coded radiographs at the second (P < 0.001) but not the first (P = 0.34) evaluation. CONCLUSIONS: Color coding of radiographic differences by means of image addition may be a feasible alternative to the subtraction technique for evaluating periodontal bone changes.     

Regional concordance and discordance between rest thallium 201 and sestamibi imaging for assessing tissue viability: Comparison with postrevascularization functional recovery

Background  

Whether the combined analysis of rest ²⁰¹Tl and sestamibi uptake provides additional information regarding myocardial viability in patients with coronary artery disease is still to be investigated.     

Quantification of severity and redistribution of ischemic and infarcted myocardium by Thallium-201 polar map: evaluation in patients with single vessel disease

Quantitative analysis of the polar map obtained from T1-201 single photon emission computed tomogram was employed to assess regional myocardial viability in 66 patients with single vessel coronary artery disease and 16 control subjects. Counts of region of interest in the stenotic and infarcted lesions and normal reference areas were calculated on the polar map. Severity of hypoperfused myocardium was determined as initial percent uptake (%Ui) and delayed percent uptake (%Ud). Redistribution was analyzed as a ratio of %Ud to %Ui (%Ud/%Ui). In the control group, the average %Ui was 85.8 +/- 9.4 and %Ud/%Ui was 1.03 +/- 0.04. Twenty five with reversible defect showed reduced %Ui (51.5 +/- 13.3) and increased %Ud/%Ui (1.37 +/- 0.26). Forty one cases with non-reversible defect were divided into two groups according to the value of %Ui. In the first group with a high %Ui (n = 17), the average %Ui was 74.5 +/- 4.7 and %Ud/Ui was in normal range (1.06 +/- 0.06). In the second group (n = 24), %Ui was most reduced (31.7 +/- 8.7), although %Ud/%Ui was in normal range (1.05 +/- 0.17). No significant correlation was shown between %Ui and %Ud/%Ui in the two groups with non-reversible defect. Correlation between %Ui and %Ud/%Ui was high (r = -0.76) in the group of reversible defect and the group of non-reversible defect with minimal reduced %Ui. It is concluded that the quantitative criteria obtained from polar map is valid to assess regional myocardial viability. The quantitative imaging data were also compared with coronary angiographic and left ventriculographic data.     

A protocol for assessing subtraction errors of arterial spin-tagging perfusion techniques in human brain.

A protocol for assessing signal contributions from static tissue (subtraction errors) in perfusion images acquired with arterial spin-labeling (ASL) techniques in human brain is proposed. The method exploits the reduction of blood T(1) caused by the clinically available paramagnetic contrast agent, gadopentetate dimeglumine (Gd-DTPA). The protocol is demonstrated clinically with multislice FAIR images acquired before, during, and after Gd-DTPA administration using a range of selective inversion widths. Perfusion images acquired postcontrast for selective inversion widths large enough (threshold) to avoid interaction with the imaging slice had signal intensities reduced to noise level, as opposed to subtraction errors manifested on images acquired using inversion widths below the threshold. The need for these experiments to be performed in vivo is further illustrated by comparison with phantom results. The protocol allows a one-time calibration of relevant ASL parameters (e.g., selective inversion widths) in vivo, which may otherwise cause subtraction errors. Magn Reson Med 43:896-900, 2000. Published 2000 Wiley-Liss, Inc.     

Comparison of conventional pulmonary angiography with intravenous digital subtraction angiography for pulmonary embolic disease

Intravenous digital subtraction pulmonary angiography was performed in 33 patients with suspected pulmonary embolism. It was performed as the initial examination, followed immediately by conventional film-screen pulmonary angiography performed with selective right or left main pulmonary injections. Intravenous studies of diagnostic quality were obtained in 31 of 33 patients (93.9%). Of the satisfactory intravenous studies, pulmonary embolism was correctly diagnosed in 12 cases and excluded in 18 cases. Emboli were detected in major and second-order branches, and occasionally in third-order branches as well. There was one false-positive intravenous pulmonary study, but the overall accuracy was 90.9% considering all studies and 96.8% excluding the two inadequate intravenous examinations. It is concluded that intravenous pulmonary angiography is an acceptable substitute for routine pulmonary angiography in most patients with suspected major pulmonary embolism. The technique is less expensive, and is safer, faster, and easier to perform than conventional pulmonary angiography.     

Enhanced sensitivity and specificity of thallium-201 imaging for the detection of regional ischemic coronary disease by combining SPECT with "bull's eye" analysis

Previous studies have indicated that the combination of single photon emission computed tomography (SPECT) and quantitative "bull's eye" analysis (QBA) TI-201 cardiac stress imaging may improve the detection of myocardial ischemia over that achieved with planar (PLN) imaging. This study will evaluate the sensitivity and specificity of SPECT and QBA in the detection of disease in the left anterior descending (LAD), left circumflex (LCX), and right coronary artery. Ninety-nine patients who underwent both TI-201 stress imaging and coronary arteriography were evaluated retrospectively. Of the 99, 62 had PLN imaging and 37 were evaluated with SPECT; 23 of these 37 had QBA. The overall sensitivity and specificity were as follows: PLN, 94% and 50%; SPECT, 90% and 67%; QBA, 100% and 20%; and SPECT with QBA, 92% and 72%, respectively. The regional sensitivity and specificity of PLN for individual coronary arteries were as follows: RCA, 78% and 74%; LAD, 89% and 60%; LCX, 50% and 89%, respectively. For SPECT, the results were: RCA, 86% and 93%; LAD, 85% and 88%; and LCX, 60% and 88%. For QBA alone, the results were: RCA, 100% and 75%; LAD, 88% and 53%; and LCX, 100% and 89%. The results for QBA with SPECT were: RCA, 100% and 94%; LAD, 88% and 80%; and LCX, 67% and 95%. Thus, SPECT interpreted on conjunction with QBA showed higher sensitivity for evaluation of ischemia in the RCA and LCX arteries and higher specificity in the detection of LAD and RCA disease than did PLN TI-201 imaging. Because of the low specificity of QBA (20%), caution is advised in the interpretation of QBA alone without reviewing SPECT images.     

Comparison of digital with conventional ventriculography for quantitative right ventricular studies

To assess the feasibility of quantitative central venous digital angiocardiography, right ventricular spatial orientation, size, and shape were compared with measurements based on conventional angiocardiography, both obtained during routine cardiac catheterization in 21 children with various congenital heart defects. Without systematic error, correlations for end-diastolic and end-systolic volumes were excellent, at r=0.986 and 0.969, respectively. Ejection fractions were similarly closely correlated. Premature ventricular contractions were common in conventional angiocardiography and absent in digital angiocardiography. The amount of contrast medium was 36% of that used for conventional angiocardiography. Digital angiocardiography using reduced amounts of contrast medium given through a central venous catheter allows accurate assessment of right ventricular size and function.     

Comparison of intra-arterial digital subtraction angiography with conventional angiography after transcatheter arterial embolization for hepatic malignancy

Twenty patients with hepatic malignancy were treated with transcatheter arterial embolization (TAE) under examination by intra-arterial digital subtraction angiography (IA-DSA) and conventional angiography (CA). Comparison of these two angiographies revealed that the time required for confirmation of the embolized portion of the artery was about four-and-a-half times shorter with IA-DSA than CA. Moreover, IA-DSA revealed the obstructed portion more readily and accurately than CA. In particular, confirmation could not be made by CA in 35% of cases because of residual Gelform sponge containing contrast medium in the artery. The visualization of residual tumor stain after TAE was 40% better on IA-DSA than CA, because of residual Gelform sponge containing contrast medium and overlapping shadow with calcified costal cartilage, excretory pyelography, and original tumor stain. However, CA was better than IA-DSA in visualizing accidental obstruction of nonobjective arteries such as the cystic artery because of the poor spatial resolution and misregistration artifacts of IA-DSA. CA was better than IA-DSA in visualizing surrounding nonembolized hepatic parenchyma because of the misregistration artifacts of IA-DSA. For effective TAE without severe complication, we concluded that TAE for HCC should be performed under a combination of IA-DSA and CA.     

Contrast enhanced ultrasound quantitative parameters for assessing neoadjuvant chemotherapy response in patients with locally advanced breast cancer

Objectives:To evaluate the role of contrast-enhanced ultrasound (CEUS) quantitative parameters in predicting neoadjuvant chemotherapy (NACT) response in patients with locally advanced breast cancer (LABC).Methods:30 patients with histologically proven LABC scheduled for NACT were recruited. CEUS was performed using a contrast bolus of 4.8 ml and time intensity curves (TICs) were obtained by contrast dynamics software. CEUS quantitative parameters assessed were peak enhancement (PE), time-to-peak (TTP), area under the curve (AUC) and mean transit time (MTT). The parameters were documented on four consecutive instances: before NACT and 3 weeks after each of the three cycles. The gold-standard was pathological response using Miller Payne Score obtained pre NACT and post-surgery.Results:A decrease in mean values of PE and an increase in mean values of TTP and MTT was observed with each cycle of NACT among responders. Post each cycle of NACT (compared with baseline pre-NACT), there was a statistically significant difference in % change of mean values of PE, TTP and MTT between good responders and poor responders (p-value < 0.05). The diagnostic accuracy of TTP post-third cycle was 87.2% (p = 0.03), and MTT post--second and third cycle was 76.7% (p = 0.004) and 86.7% (p = 0.006) respectively.Conclusion:In responders, a decrease in the tumor vascularity was reflected in the CEUS quantitative parameters as a reduction in PE, and a prolongation in TTP, MTT.Advances in knowledge:Prediction of NACT response by CEUS has the potential to serve as a diagnostic modality for modification of chemotherapy regimens during ongoing NACT among patients with LABC, thus affecting patient prognosis.     

Pelvic imaging with a selenium-based detector (Thoravision). Comparison with screen-film radiography in 75 patients

OBJECTIVE: To evaluate whether the selenium detector (Thoravision) provides sufficient diagnostic confidence in digital pelvic imaging compared with a conventional screen-film combination. METHODS: In 75 patients, pelvic imaging with conventional screen-film and isodose selenium radiography using a dedicated postprocessing mode was compared independently by three radiologists. The depiction of cortical and cancellous bone was evaluated in the iliac wings, sacral and pubic bones, acetabulum, femoral head, and trochanter. Demarcation of soft tissue was assessed in the iliac and trochanteric region. RESULTS: Visualization of cortical bone and soft tissue in the iliac area as well as soft tissue and cortical and cancellous bone in the trochanteric region was significantly superior with the selenium detector. However, conventional imaging was better in the trabecular bone of the sacral region, where results with the selenium system were particularly poor. CONCLUSIONS: The selenium detector (Thoravision) is advantageous in imaging soft tissue adjacent to the iliac wings and the trochanter, but results for the cancellous sacral bone are poor. Further modifications of postprocessing modes may lead to improved depiction of this critical pelvic area.     

Noninvasive PET quantitative myocardial blood flow with regadenoson for assessing cardiac allograft vasculopathy in orthotopic heart transplantation patients

Background

Risk stratification and early detection of cardiac allograft vasculopathy (CAV) is essential in orthotopic heart transplantation (OHT) patients. This study assesses the changes in myocardial blood flow (MBF) noninvasively in OHT patients using quantitative cardiac PET with regadenoson.

Methods

Twelve patients (Group 1) (8 males, 4 females, mean age 55 ± 7 years) with no history of post OHT myocardial ischemia were enrolled 5.4 ± 2.0 years after OHT. Fifteen patients (Group 2) (9 males, 6 females, mean age 71 ± 9 years) with intermediate pretest probability but not documented evidence for coronary artery disease (CAD) were also included to serve as control. Global and regional MBFs were assessed using dynamic ¹³N-NH₃ PET at rest and during regadenoson-induced hyperemia. The coronary flow reserve (CFR) was also calculated as the ratio of hyperemic to resting MBF.

Results

Mean regadenoson-induced rate-pressure products were similar in both groups, while there was an increase in resting rate-pressure product in Group 1 patients. Both mean and median values of resting MBF were higher in Group 1 than Group 2 patients (1.33 ± 0.31 and 1.01 ± 0.21 mL/min/g for Groups 1 and 2, respectively, P < .001), while mean hyperemic MBF values were similar in both Groups (2.68 ± 0.84 and 2.64 ± 0.94 mL/min/g, P = NS) but median hyperemic MBF values were lower in Group 1 than Group 2 patients (2.0 vs. 2.60 mL/min/g, P = .018). Both mean and median CFR values demonstrated a significant reduction for Group 1 compared to Group 2 patients (2.07 ± 0.74 vs 2.63 ± 0.48, P = .025).

Conclusions

This study suggests that the MBF in OHT patients may be abnormal at resting state with diminished CFR. This hints that the epicardial and microvascular coronary subsystem may be exacerbated after OHT leading to the gradual progression of CAV.