Microvascular perfusion in infarcted and remote myocardium after successful primary PCI: angiographic and CMR findings.

OBJECTIVES: The aim of this study was to investigate the association between TIMI myocardial perfusion (TMP) grading acute and cardiac magnetic resonance (CMR) first-pass perfusion early and at 4 months in patients with ST-segment-elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI). MATERIAL AND METHODS: One hundred ninety-eight STEMI patients were recruited from the POSTEMI study. TMP grade was assessed after PCI; CMR was performed at day 2 and after 4 months. Signal intensity was measured on first-pass perfusion images, and a maximum contrast enhancement index (MCE) was calculated. RESULTS: Patients with TMP grade 2-3 (n = 108) after PCI had significantly better EF (59 ± 10 vs. 51 ± 13, p < 0.001) and smaller infarct volume (12 ± 8 vs. 19 ± 12 %, p < 0.001) at 4 months compared with patients with TMP grade 0-1 (n = 81). MCE in the infarcted (MCEi) and remote myocardium (MCEr) improved from early to follow-up CMR, MCEi from 94 ± 56 to 126 ± 59, p < 0.001, and MCEr from 112 ± 51 to 127 ± 50, p < 0.001. In patients with the lowest CMR perfusion early, perfusion at 4 months remained decreased compared with the other groups, MCEi 108 ± 75 vs. 133 ± 51, p = 0.01, and MCEr 115 ± 41 vs. 131 ± 52, p = 0.047. CONCLUSION: TMP grade and early CMR first-pass perfusion were associated with CMR outcomes at 4 months. First-pass perfusion improved after 4 months in the infarcted and remote myocardium. However, in patients with the lowest CMR perfusion early, perfusion was still reduced after 4 months. KEY POINTS: • Cardiac magnetic resonance myocardial first-pass perfusion and TMP grading after successful PCI helps to assess risk in patients with ST elevation myocardial infarction. • Cardiac magnetic resonance myocardial first-pass perfusion shows that microvascular perfusion after ST elevation myocardial infarction can be impaired in both infarcted and non-infarcted myocardium. • Microvascular perfusion improves over time in patients with ST elevation myocardial infarction treated with primary PCI.

Inter- and intra-observer variability of computed tomography-based parenchymal- and ductal diameters in chronic pancreatitis: a multi-observer international study.

PURPOSE: The need for incorporation of quantitative imaging biomarkers of pancreatic parenchymal and ductal structures has been highlighted in recent proposals for new scoring systems in chronic pancreatitis (CP). To quantify inter- and intra-observer variability in CT-based measurements of ductal- and gland diameters in CP patients. MATERIALS AND METHODS: Prospectively acquired pancreatic CT examinations from 50 CP patients were reviewed by 12 radiologists and four pancreatologists from 10 institutions. Assessment entailed measuring maximum diameter in the axial plane of four structures: (1) pancreatic head (PDhead), (2) pancreatic body (PDbody), (3) main pancreatic duct in the pancreatic head (MPDhead), and (4) body (MPDbody). Agreement was assessed by the 95% limits of agreement with the mean (LOAM), representing how much a single measurement for a specific subject may plausibly deviate from the mean of all measurements on the specific subject. Bland-Altman limits of agreement (LoA) were generated for intra-observer pairs. RESULTS: The 16 observers completed 6400 caliper placements comprising a first and second measurement session. The widest inter-observer LOAM was seen with PDhead (± 9.1 mm), followed by PDbody (± 5.1 mm), MPDhead (± 3.2 mm), and MPDbody (± 2.6 mm), whereas the mean intra-observer LoA width was ± 7.3, ± 5.1, ± 3.7, and ± 2.4 mm, respectively. CONCLUSION: Substantial intra- and inter-observer variability was observed in pancreatic two-point measurements. This was especially pronounced for parenchymal and duct diameters of the pancreatic head. These findings challenge the implementation of two-point measurements as the foundation for quantitative imaging scoring systems in CP.

MR findings of microvascular perfusion in infarcted and remote myocardium early after successful primary PCI.

OBJECTIVES: The aim of the study was to evaluate CMR myocardial first-pass perfusion in the injured region as well as the non-infarcted area in ST-elevation myocardial infarction (STEMI) patients few days after successful primary percutaneous coronary intervention (PCI). MATERIALS AND METHODS: 220 patients with first time STEMI successfully treated with PCI (with or without postconditioning) were recruited from the Postconditioning in STEMI study. Contrast enhanced CMR was performed at a 1.5 T scanner 2 (1-5) days after PCI. On myocardial first-pass perfusion imaging signal intensity (SI) was measured in the injured area and in the remote myocardium and maximum contrast enhancement index (MCE) was calculated. MCE = (peak SI after contrast-SI at baseline) / SI at baseline x 100. RESULTS: There were no significant differences in first-pass perfusion between patients treated with standard PCI and patients treated with additional postconditioning. The injured myocardium showed a significantly lower MCE compared to remote myocardium (94 ± 55 vs. 113 ± 49; p < 0.001). When patients were divided into four quartiles of MCE in the injured myocardium (MCE injured myocardium), patients with low MCE injured myocardium had: significantly lower ejection fraction (EF) than patients with high MCE injured myocardium, larger infarct size and area at risk, smaller myocardial salvage and more frequent occurrence of microvascular obstruction on late gadolinium enhancement. MCE in the remote myocardium revealed that patients with larger infarction also had significantly decreased MCE in the non-infarcted, remote area. CONCLUSION: CMR first-pass perfusion can be impaired in both injured and remote myocardium in STEMI patients treated with primary PCI. These findings indicate that CMR first-pass perfusion may be a feasible method to evaluate myocardial injury after STEMI in addition to conventional CMR parameters.

Myocardial perfusion grade predicts final infarct size and left ventricular function in patients with ST-elevation myocardial infarction treated with a pharmaco-invasive strategy (thrombolysis and early angioplasty).

AIMS: Primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) usually restores TIMI 3 flow in the occluded artery, but microvascular impairment may persist in >30% of patients. Less is known about microvascular reperfusion in STEMI patients treated with thrombolysis followed by early PCI. We aimed to assess the association between TIMI myocardial perfusion (TMP) at the end of the PCI procedure and left ventricular function (LVEF) and infarct size after three months in such patients. METHODS AND RESULTS: Patients with STEMI treated with thrombolysis and early PCI were included. TMP grade was assessed at the end of the PCI procedure, and MRI was performed after three months. Of the 89 patients included, 92% (n=82) had TIMI 3 flow at the end of the PCI procedure, while only 62% (n=55) had TMP grade 2 or 3. Patients with TMP grade 2-3 had significantly higher LVEF (59% [53-67] vs. 50% [41-56], p<0.0001) and smaller infarct size (8.3 ml [2.7-15.5] vs. 20.7 ml [13.0-36.0], p<0,0001) after three months. CONCLUSIONS: In STEMI patients treated with thrombolysis and early PCI, the TMP grade at the end of the PCI procedure was significantly associated with LVEF and infarct size after three months.

The economic benefit for family/general medicine practices employing physician assistants.

OBJECTIVE: To measure the economic benefit of a family/general medicine physician assistant (PA) practice. STUDY DESIGN: Qualitative description of a model PA practice in a family/general medicine practice office setting, and comparison of the financial productivity of a PA practice with that of a non-PA (physician-only) practice. METHODS: The study site was a family/general medicine practice office in southwestern Pennsylvania. The description of PA practice was obtained through direct observation and semistructured interviews during site visits in 1998. Comparison of site practice characteristics with published national statistics was performed to confirm the site's usefulness as a model practice. Data used for PA productivity analyses were obtained from site visits, interviews, office billing records, office appointment logs, and national organizations. RESULTS: The PA in the model practice had a same-task substitution ratio of 0.86 compared with the supervising physician. The PA was economically beneficial for the practice, with a compensation-to-production ratio of 0.36. Compared with a practice employing a full-time physician, the annual financial differential of a practice employing a full-time PA was $52,592. Sensitivity analyses illustrated the economic benefit of a PA practice in a variety of theoretical family/general medicine practice office settings. CONCLUSIONS: Family/general medicine PAs are of significant economic benefit to practices that employ them.

Neoadjuvant treatment of colorectal liver metastases is associated with altered contrast enhancement on computed tomography.

Neoadjuvant systemic therapy may induce steatosis or sinusoid obstruction syndrome in the liver. The aim of this study was to investigate the influence of systemic therapy with irinotecan, oxaliplatin and cetuximab on conspicuity of liver metastases on computed tomography (CT). CT scans of 48 patients with initial unresectable colorectal liver metastases which were treated in a Europe-wide, opened, randomized phase II trial receiving oxaliplatin or irinotecan combined with folinic acid and cetuximab were analysed. The density of the metastases and the liver parenchyma before and after systemic therapy were analysed by region-of-interest technique and the tumour-to-liver difference (dHU TLD). The mean density of liver parenchyma and liver metastases did not vary significantly before and after neoadjuvant therapy on plain (56.3 ± 8.1 HU, 54.8 ± 13.5 HU) and arterial enhanced CT (76.0 ± 15.7 HU, 70.5 ± 20.4 HU). There was a significant reduction (105.6 ± 17.3 HU, 93.3 ± 18.2 HU) in the density of liver parenchyma on portal venous scans after systemic therapy (p < 0.0001) and a reduction of dHU TLD, consecutively. In patients with colorectal liver metastases, neoadjuvant chemotherapy may have a toxic impact on liver parenchyma resulting in reduced tumour-to-liver contrast in contrast-enhanced CT. This may lead to underestimation of real lesion size.