Diagnostic performance of IQ·SPECT with high-speed scanning: A preliminary quality control study in obese patients.

BACKGROUND: IQ·SPECT is a recently introduced collimator design for myocardial perfusion imaging (MPI). Little data exist on use of this collimator type in obese patients, particularly Class 2 or 3 [body mass index (BMI) > 35 kg/m2]. METHODS: Two consecutive rest-stress MPI scans were prospectively acquired using a conventional collimator and IQ·SPECT (acquisition times of 20 and 7 minutes, respectively) in 20 patients with a BMI of >30 kg/m2. Assigned by two blinded, independent readers, image quality (on a 5-point scale) and metrics of myocardial perfusion [summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS)] were compared. Software-based left ventricular ejection fraction (EF) was also correlated. RESULTS: Mean BMI was 39.6 ± 7.6 kg/m2. Class 2 or 3 obesity was present in 12 patients (BMI, 44.1 ± 6.8 kg/m2). Gated/non-gated images from IQ·SPECT revealed fair to good quality scores (median ≥ 3.25), which were inferior to the conventional collimator (median ≥ 4.0; P ≤ 0.01). Significant correlative indices were achieved when comparing IQ·SPECT and conventional collimators for EF values (r = 0.86, P < 0.01), SSS (r = 0.75, P < 0.0001) and SRS (r = 0.60, P < 0.005), but not for SDS (r = 0.15). CONCLUSION: IQ·SPECT was comparable to conventional SPECT in obese patients. The reduced acquisition time of IQ·SPECT may allow for improved throughput with no loss in diagnostic accuracy.

Distribution of intimomedial tears in patients with type B aortic dissection.

OBJECTIVE: Thoracic endovascular aortic repair is a promising means of treating patients with complicated type B aortic dissection by excluding the intimomedial tears. This study aims to characterize the location of tears and to propose a classification of type B aortic dissections based on these findings. METHODS: Advanced protocols in computed tomography scans of patients with type B aortic dissection were used to identify the size and location of intimomedial tears in relation to the origin of the left subclavian artery. Aortic imaging details in 72 un-operated patients were used as a reference standard. From 1999 to 2005, 44 patients underwent primary endovascular treatment for complications of type B aortic dissection. RESULTS: Each patient had an average of 2.8 +/- 2.11 intimomedial tears. The median intimomedial tear surface area was 0.63 cm(2). The presence of >or=3 or >or=5 intimomedial tears in the descending thoracic aorta did not correlate with aortic branch malperfusion (P > .05). Thirteen of 26 (50%) patients with a tear >1.9 cm(2) had aortic branch malperfusion (P = .032). Ten of 14 (71%) patients with a tear >4.86 cm(2) (mean plus one standard deviation) had aortic branch malperfusion (P = .002). The location of tears ranged from -6 mm to +459.2 mm from the left subclavian artery orifice: 80.5% (n = 99) of these tears were above the reference origin of the celiac artery. Eight of 13 patients (62%) with a tear distal to 282 mm (the orifice of the celiac artery) had aortic branch malperfusion in (P = .04). A classification for the location of intimomedial tears is proposed with potential clinical relevance to endovascular repair: type 1 has no identifiable tears; type 2 has one or more tears with no tears distal to the orifice of the celiac artery; type 3 has tears involving the branch vessels of the abdominal aorta; and type 4 has intimomedial tears distal to the aortic bifurcation. CONCLUSIONS: Characterization and location of intimomedial tears using computed tomography (CT) imaging is feasible and represents an important step in the management of type B aortic dissection. The location and surface area of tears is associated with malperfusion. Based on the proposed classification and anatomic reference data, three out of every four patients may have a favorable constellation of intimomedial tears (type 1 or 2) that would be amenable to endovascular repair and reverse aortic remodeling. The clinical correlation will be established in upcoming studies.

Guidewires, catheters, and sheaths used for thoracic endografting procedures.

BACKGROUND: Endovascular repair represents an option becoming progressively more integral to the treatment of thoracic aortic pathology. Effective use by practitioners of the most appropriate endovascular equipment is essential to the continued growth of this treatment modality. This article aims to provide an overview of the guidewires, catheters, and sheaths employed in the practice of thoracic endovascular aortic repair (TEVAR). METHODS: We reviewed our current utilization of guidewires, catheters, and sheaths in TEVAR. Concurrently, we conducted a survey of the present medical literature with regard to the materials and methods used in this procedure by other cardiothoracic surgeons, vascular surgeons, and interventional radiologists. RESULTS: Fundamental principals of the guidewires, catheters, and sheaths used in TEVAR are consistent across the spectrum of specialists performing this procedure. However, considerable variation exists in the specific products used by practitioners. CONCLUSIONS: The importance of proper training and experience with the endovascular equipment used in TEVAR cannot be understated. We believe the endovascular tools discussed in this article offer a proper selection for safe and effective performance of these procedures.

Adding value to myocardial perfusion SPECT/CT studies that include coronary calcium CT: Detection of incidental pulmonary arterial dilatation.

The aim of the present study was to evaluate the incidence of undiagnosed pulmonary arterial dilatation using the gated computed tomography (CT) images acquired in patients with an otherwise normal Tc-sestamibi single-photon-emission CT (SPECT)/CT myocardial perfusion study.This was a retrospective review of 200 consecutive patients (100 men, mean age 58.7 years) who underwent a myocardial perfusion Tc-sestamibi SPECT/CT study with normal perfusion and with gated CT images acquired for coronary calcium scoring. The CT images were reviewed using a previously validated mean main pulmonary artery diameter (mPAD) measurement method which has been correlated with pulmonary arterial hypertension (PAH). Clinical information on multiple comorbidities was also retrieved. Previously reported mPAD cutoffs (>29.5 and >31.5 mm) were used to stratify patients.Indications for the study included dyspnea on exertion (58.9%), preoperative workup (22.3%), and chest pain (13.9%). The mean mPAD measurement was 26.3 mm (±0.5). There was a significant correlation between body mass index and mPAD (correlation coefficient [ρ]: 0.28; P < .001). About 23% (46/200) of patients had mPAD > 29.5 mm and 15.0% (30/200) of patients had mPAD > 31.5 mm. From previous work, these cutoffs have a sensitivity and specificity for PAH of 70.8%, 79.4% and 52.0%, 90.2%, respectively. Among patients undergoing a preoperative myocardial perfusion study, 35.6% (16/45) patients had mPAD > 29.5 mm and 26.7% (12/45) patients had mPAD > 31.5 mm. There was a higher prevalence of congestive heart failure (62.5% vs 19.6%; P < .001) and hypertension (78.3% vs 21.7%; P < .02) in patients with mPAD > 29.5 mm. Similarly, there was a high prevalence of congestive heart failure (P < .001), hyperlipidemia (P < .04), and hypertension (P < .04) in patients with mPAD > 31.5 mm.Incidental pulmonary arterial dilatation (mPAD ≥ 29.5 mm) can be detected in a large number of patients with normal myocardial perfusion scintigraphy and correlates with multiple different comorbidities. The mPAD can be measured in all patients undergoing gated imaging as part of a myocardial perfusion study, and PAH may be considered as an alternative explanation for symptoms in some patients without perfusion deficits. The data to make this potential diagnosis is already being acquired and represents an opportunity to add value to the interpretations of otherwise negative myocardial perfusion studies.

Post-treatment 18F-FDG-PET/CT versus contrast-enhanced CT in patients with oropharyngeal squamous cell carcinoma: comparative effectiveness study.

OBJECTIVE: To compare the accuracy of same-day therapy-assessment PET/computed tomography (PET/CT) and conventional contrast-enhanced computed tomography (CECT) in patients with oropharyngeal squamous cell carcinoma (OPSCC). METHODS: A total of 110 (95 men and 15 women; mean age 59 years) patients with biopsy-proven OPSCC were evaluated with same-day PET/CT and CECT pair scans as part of follow-up therapy assessment. Scans were performed within 6 months after the completion of primary treatment (median time: 3.1 months; range: 0.5-6 months). PET/CT and CECT scans were reviewed retrospectively for residual primary site disease, and right and left cervical lymph node involvement. Histopathology or 6 month clinical/imaging follow-up were used as the gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the primary site and cervical nodal disease. RESULTS: Of 110 OPSCC patients, 90.9% were human papilloma virus positive, 80.8% were stage 4, and 76.4% received chemoradiation as the primary treatment. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT were similar in the evaluation of the primary cancer site (PET/CT: 75.0, 91.5, 25.0, 99.0, and 90.9, respectively, versus CECT: 75.0, 90.6, 23.1, 99.0, and 90.0, respectively). In evaluating cervical lymph node involvement, PET/CT appeared to have higher accuracy (96.8 vs. 81.7%), specificity (97.7 vs. 81.7%), and PPV (45.8 vs. 16.5%), comparable NPV (99.4% for both), and lower sensitivity (65 vs. 75%) compared with same-day CECT. CONCLUSION: Same-day PET/CT and CECT scans had comparable accuracy in the evaluation of primary tumor sites after completion of therapy in patients with OPSCC. PET/CT showed higher accuracy in the evaluation of cervical lymph node involvement.

Myocardial Blood Flow and Inflammatory Cardiac Sarcoidosis.

OBJECTIVES: This study sought to evaluate the effects of inflammatory sarcoid disease on coronary circulatory function and the response to immune-suppressive treatment. BACKGROUND: Although positron emission tomography assessment of myocardial inflammation is increasingly applied to identify active cardiac sarcoidosis, its effect on coronary flow and immune-suppressive treatment remains to be characterized. METHODS: Thirty-two individuals, who were referred for positron emission tomography/computed tomography, were evaluated for known or suspected cardiac sarcoidosis applying 18F-fluorodeoxyglucose to determine inflammation and 13N-ammonia to assess for perfusion deficits following a high-fat/low-carbohydrate diet and fasting state >12 h to suppress myocardial glucose uptake. Inflammation was quantified with standardized uptake value and regional myocardial blood flow at rest and during regadenoson-stimulated hyperemia was determined in ml/g/min. Positron emission tomography studies were repeated in 18 cases with a median follow-up of 2.5 years (interquartile range [IQR]:1.3 to 3.4 years). RESULTS: Twenty-five exams had normal perfusion but evidence of regional inflammation (group 1), and 21 exams presented a regional perfusion deficit associated with inflammation (group 2). Median myocardial blood flow did not differ between inflamed and noninflamed myocardium in both groups (0.86 ml/g/min [IQR: 0.66 to 1.11 ml/g/min] vs. 0.83 ml/g/min [IQR: 0.64 to 1.12 ml/g/min] and 0.74 ml/g/min [IQR: 0.60 to 0.93 ml/g/min] vs. 0.77 ml/g/min [IQR: 0.59 to 0.95 ml/g/min], respectively). As regards median hyperemic myocardial blood flows, they were significantly lower in the inflamed than in the remote regions in group 1 and 2 (2.31 ml/g/min [IQR: 1.81 to 2.95 ml/g/min] vs. 2.70 ml/g/min [IQR: 2.07 to 3.30 ml/g/min] and 1.61 ml/g/min [IQR: 1.17 to 2.18 ml/g/min] vs. 1.94 ml/g/min [IQR: 1.49 to 2.39 ml/g/min]; p < 0.001, respectively). Immune-suppression-mediated decrease in inflammation was associated with preserved myocardial flow reserve (MFR) at follow-up, whereas MFR significantly worsened in regions without changes or even increases in inflammation (median ΔMFR: 0.07 [IQR: -0.29 to 0.45] vs. -0.24 [IQR: -0.84 to 0.21]; p < 0.001). There was an inverse correlation between pronounced alterations in myocardial inflammation (Δ regional myocardial volume with standardized uptake value >4.1) and ΔMFR (r = -0.47; p = 0.048). CONCLUSIONS: Sarcoid-mediated myocardial inflammation is associated with a regional impairment of coronary circulatory function. The association between immune-suppressive treatment-related alterations in myocardial inflammation and changes in coronary vasodilator capacity suggests direct adverse effect of inflammation on coronary circulatory function in cardiac sarcoidosis.

A leukemic presentation of alveolar rhabdomyosarcoma in a 52-year-old woman without an identifiable primary tumor.

A 52-year-old woman presented with fatigue and thrombocytopenia. Imaging studies were unremarkable with the exception of a positron emission tomography scan, which demonstrated intense F-18 fluorodeoxyglucose uptake fusing to the marrow. A bone marrow aspirate was notable for large discohesive cells with basophilic cytoplasm, and flow cytometric analysis identified a population of phenotypically unusual cells that coexpressed CD56 and CD71. Immunohistochemical findings in the marrow biopsy demonstrated that the neoplasm was alveolar rhabdomyosarcoma, further supported by the presence of a t(2;13). This unusual case demonstrates that leukemic presentations of rhabdomyosarcoma can occur in older adults in the absence of an identifiable primary tumor.

Aortic intramural hematoma: review of high-risk imaging features.

Aortic intramural hematoma is among the spectrum of pathologies that comprises acute aortic syndrome and carries a risk of progression to aortic dissection, aneurysm, rupture, and other complications. Evaluation by CT can identify imaging features associated with higher risk of complications. Ulcer-like projections, enlarged aortic diameter, increased hematoma thickness, and Stanford type A classification are associated with progression to complications. The significance of intramural blood pools within the hematoma and associated pleural/pericardial effusions is less certain. Detailed evaluation of intramural hematoma with CT can provide critical prognostic information with implications for patient management.

Incidence and risk factors of renal dysfunction after thoracic endovascular aortic repair.

OBJECTIVES: The risk of renal failure after thoracic endovascular aortic repair is not widely established. The aim of this study was to assess the incidence and risk factors of renal failure. METHODS: Between 1998 and 2008, 175 consecutive patients underwent 210 procedures at 2 tertiary academic institutions. Similar nephroprotective protocols and intravascular ultrasound were used. Retrospective analysis was performed. Generalized linear model was used to identify factors associated with change in postoperative estimated glomerular filtration rate. RESULTS: Underlying aortic diseases included 103 aneurysms, 72 dissections, 21 transections, and 14 penetrating ulcers. Median preoperative estimated glomerular filtration rate was 65 mL · min(-1) · 1.73 m(-2). Contrast media averaged 108.7 ± 69.8 mL. Median estimated glomerular filtration rates within 48 hours and 30 days were 69 and 67 mL · min(-1) · 1.73 m(-2), respectively. Rates of acute renal dysfunction risk (>25% estimated glomerular filtration rate decrease), acute kidney injury (>50% estimated glomerular filtration rate decrease), acute kidney function failure (>75% estimated glomerular filtration rate decrease), and hemodialysis were 9.8% (19/193), 1.6% (3/193), 0% (0/193), and 0.5% (1/193), respectively. Rates of renal dysfunction at 1 month and 6 months were 13.3% (10/75) and 17.7% (6/34), respectively. Risk factors for acute renal dysfunction were intraoperative hypotension, stroke, sepsis, lengthy procedures, and number of stents; at 1 and 6 months they were increased age, male gender, African American race, diabetes mellitus, chronic pulmonary disease, smoking, and zone 0 to 1 graft deployment. Obesity was nephroprotective. CONCLUSIONS: Thoracic aortic endograft has a significant rate of renal dysfunction; however, it is lower in this cohort than in previous smaller series. Routine use of intravascular ultrasound and reduced contrast may have contributed to lower rates of renal insufficiency.

Use of transcranial Doppler ultrasound in endovascular repair of a type B aortic dissection.

Intraprocedural monitoring with transcranial Doppler ultrasound in thoracic endovascular aortic repair provides critical information regarding the occurrence of cerebral microemboli and adequacy of cerebral blood flow. We present the perioperative course of a patient with complicated Stanford type B aortic dissection undergoing thoracic endovascular aortic repair with continuous intraoperative transcranial Doppler ultrasound monitoring.