Neural networks for nodal staging of non-small cell lung cancer with FDG PET and CT: importance of combining uptake values and sizes of nodes and primary tumor.

PURPOSE: To evaluate the effect of adding lymph node size to three previously explored artificial neural network (ANN) input parameters (primary tumor maximum standardized uptake value or tumor uptake, tumor size, and nodal uptake at N1, N2, and N3 stations) in the structure of the ANN. The goal was to allow the resulting ANN structure to relate lymph node uptake for size to primary tumor uptake for size in the determination of the status of nodes as human readers do. MATERIALS AND METHODS: This prospective study was approved by the institutional review board, and informed consent was obtained from all participants. The authors developed a back-propagation ANN with one hidden layer and eight processing units. The data set used to train the network included node and tumor size and uptake from 133 patients with non-small cell lung cancer with surgically proved N status. Statistical analysis was performed with the paired t test. RESULTS: The ANN correctly predicted the N stage in 99.2% of cases, compared with 72.4% for the expert reader (P < .001). In categorization of N0 and N1 versus N2 and N3 disease, the ANN performed with 99.2% accuracy versus 92.2% for the expert reader (P < .001). CONCLUSION: The ANN is 99.2% accurate in predicting surgical-pathologic nodal status with use of four fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT)-derived parameters. Malignant and benign inflammatory lymph nodes have overlapping appearances at FDG PET/CT but can be differentiated by ANNs when the crucial input of node size is used.

The Economic Value of Hybrid Single-photon Emission Computed Tomography With Computed Tomography Imaging in Pulmonary Embolism Diagnosis.

OBJECTIVE: The objective was to quantify the potential economic value of single-photon emission computed tomography (SPECT) with computed tomography (CT; SPECT/CT) versus CT pulmonary angiography (CTPA), ventilation-perfusion (V/Q) planar scintigraphy, and V/Q SPECT imaging modalities for diagnosing suspected pulmonary embolism (PE) patients in an emergency setting. METHODS: An Excel-based simulation model was developed to compare SPECT/CT versus the alternate scanning technologies from a payer's perspective. Clinical endpoints (diagnosis, treatment, complications, and mortality) and their corresponding cost data (2016 USD) were obtained by performing a best evidence review of the published literature. Studies were pooled and parameters were weighted by sample size. Outcomes measured included differences in 1) excess costs, 2) total costs, and 3) lives lost per annum between SPECT/CT and the other imaging modalities. One-way (±25%) sensitivity and three scenario analyses were performed to gauge the robustness of the results. RESULTS: For every 1,000 suspected PE patients undergoing imaging, expected annual economic burden by modality was found to be 3.2 million (SPECT/CT), 3.8 million (CTPA), 5.8 million (planar), and 3.6 million (SPECT) USD, with a switch to SPECT/CT technology yielding per-patient-per-month cost savings of $51.80 (vs. CTPA), $213.80 (vs. planar), and $36.30 (vs. SPECT), respectively. The model calculated that the incremental number of lives saved with SPECT/CT was six (vs. CTPA) and three (vs. planar). Utilizing SPECT/CT as the initial imaging modality for workup of acute PE was also expected to save $994,777 (vs. CTPA), $2,852,014 (vs. planar), and $435,038 (vs. SPECT) in "potentially avoidable"' excess costs per annum for a payer or health plan. CONCLUSION: Compared to the currently available scanning technologies for diagnosing suspected PE, SPECT/CT appears to confer superior economic value, primarily via improved sensitivity and specificity and low nondiagnostic rates. In turn, the improved diagnostic accuracy accords this modality the lowest ratio of expenses attributable to potentially avoidable complications, misdiagnosis, and underdiagnosis.

Improved prediction of lobar perfusion contribution using technetium-99m-labeled macroaggregate of albumin single photon emission computed tomography/computed tomography with attenuation correction.

OBJECTIVE: Lung cancer resection can require removal of an entire lobe and, at times, bilobectomy or pneumonectomy. Many patients will also have significantly compromised lung function that requires limiting the extent of surgery or could preclude surgery altogether. The preoperative assessment should include predicted postoperative forced expiratory volume in 1 second (ppoFEV1), because a ppoFEV1 of <40% predicts significantly increased perioperative morbidity. The ppoFEV1 can be estimated by multiplying the preoperative FEV1 by the residual perfused territory percentage, as predicted on planar perfusion scintigraphy (PPS). However, ppoFEV1 using PPS has shown variable correlation with spirometry-measured postoperative FEV1. METHODS: We propose an improved method for assessing regional lung perfusion in preoperative lung surgery patients. Patients undergo single photon emission computed tomography/computed tomography (SPECT/CT) imaging with attenuation correction using the conventional perfusion agent, technetium-99m-labeled macroaggregate of albumin. The CT image provides information for manual segmentation of each lobe. These segmentations are applied to the SPECT images to determine lobar perfusion. This proposed method was compared with PPS. RESULTS: This technique was evaluated in 17 patients. As expected, the perfusion contributions of the right and left lungs, calculated from SPECT/CT, correlated closely with those obtained from PPS (Pearson r=0.995). However, the lobar perfusion contributions obtained by PPS and SPECT/CT were significantly different, by 2 methods of comparison (Hotelling's P=1.7×10(-6) and P=1.7×10(-4)). CONCLUSIONS: This new SPECT/CT technique provides an anatomically more accurate assessment of lobar perfusion. This technique can refine which patients should be operative candidates and allow better prediction of postoperative function in contrast to the anatomically inaccurate planar scintigraphic predictions, which often underestimate the postoperative FEV1. This new technique is expected to have a significant effect on the resectability of patients with lung cancer.

Ventilation/Perfusion scanning for acute pulmonary embolism: effect of direct communication on patient treatment outcomes.

PURPOSE OF THE REPORT: Although the synthesis of ventilation-perfusion (V/Q) scan result and clinical pretest probability is vital to the diagnostic accuracy of V/Q scanning, there is no updated pretest/posttest tabular decision tool since that presented in the Prospective Investigation of Pulmonary Embolism Diagnosis I data. Because this verbal communication between the nuclear medicine physician and referring clinician is indispensable in this process, we sought to study the relationship between documentation of such communication (DCOMM) of the result of a V/Q scan and patient treatment outcome in patients with suspected acute pulmonary embolus (PE). METHODS: Electronic medical records were searched for patients who underwent V/Q scan for the workup of acute pulmonary embolism from 2000 through 2009 at Harborview Medical Center in Seattle, Washington. RESULTS: Sin hundred eighty-two patients were included in the analysis. Ventilation-perfusion scan outcomes are reported categorically as normal (N), very low (V), low (L), intermediate (I), or high (H) probability. The distribution of V/Q results was 58 (N), 58 (V), 454 (L), 83 (I), and 29 (H). The treatment rates by group were 1.7% (N), 1.7% (V), 1.1% (L), 25.3% (I), and 96.6% (H). The rates of electronic documentation of communication between the nuclear medicine physician and referring physician were 16% (N), 22% (V), 19% (L), 30% (I), and 69% (H). In a logistic regression analysis, odds ratios for treatment relative to the N group were 1596 (P < 0.001) (H), 19 (P < 0.01) (I), and 0.63 (not statistically significant) (L). DCOMM predicted a higher rate of treatment, independent of the outcome of the V/Q scan. In a multivariate logistic regression, the odds ratio for treatment after DCOMM is 2.7 (P < 0.05) and increases to 4.8 (P < 0.01) when on-call studies are excluded. CONCLUSIONS: Review of 682 patients who underwent V/Q scan for suspected PE during 2000-2009 at a single institution demonstrates that DCOMM is a strong predictor of subsequent treatment for PE, across all probability outcomes. The results of this study demonstrate the potential effect of verbal communication from nuclear medicine physicians in this decision process, and a suggested precedent for critical results is presented.

Nuclear medicine in cerebrovascular disease.

Stroke and cerebrovascular diseases are major causes of mortality, morbidity, and disability. Nuclear Medicine, primarily via tomographic methods, has made significant contributions to the understanding of the hemodynamic and metabolic consequences of cerebrovascular diseases. In this review, the findings in acute, subacute, and chronic cerebrovascular diseases are described. Many of the pathophysiologic processes and consequences that follow stroke, including completed infarct core, adjacent penumbra, and diaschisis, have been investigated with Nuclear Medicine, and stroke outcome may be related to these phenomena. Additional topics included in this review are cerebrovascular reserve tests and multi-infarct dementia. Finally, Nuclear Medicine investigations of stroke recovery and cerebral plasticity appear to indicate that enhanced activity of preexisting networks, rather than substitution of function, represents the most important mechanism of improvement in chronic stroke rehabilitation.