First demonstration of leukemia imaging with the proliferation marker 18F-fluorodeoxythymidine

Acute myeloid leukemia (AML) is a neoplasm of hematopoietic stem cells with partial or complete loss of the ability to differentiate but with preserved proliferation capacity. The aim of our study was to evaluate if the in vivo proliferation marker 3'-deoxy-3'-18F-fluorothymidine (FLT) is suitable for visualizing leukemia manifestation sites and if 18F-FLT is a surrogate marker for disease activity. METHODS: In this pilot study, 10 patients with AML underwent pretherapeutic imaging with 18F-FLT PET or 18F-FLT PET/CT. The biodistribution of 18F-FLT was assessed 60 min after intravenous injection of the radiotracer. Standardized uptake values were calculated for reference segments of bone marrow, spleen, and normal organs. 18F-FLT PET in 10 patients with benign pulmonary nodules and the absence of malignant or inflammatory disease served as controls. RESULTS: Retention of 18F-FLT was observed predominantly in bone marrow and spleen and was significantly higher in AML patients than in controls (mean 18F-FLT SUV in bone marrow, 11.5 and 6.6, P < 0.05; mean 18F-FLT SUV in spleen, 6.1 and 1.8, P < 0.05). Outside bone marrow, focal 18F-FLT uptake showed extramedullary manifestation sites of leukemia in 4 patients (meningeal disease, pericardial, abdominal, testicular, and lymph node), proven by other diagnostic procedures. CONCLUSION: This pilot study indicated that PET using 18F-FLT is able to visualize extramedullary manifestation sites of AML and reflects disease activity. Because 18F-FLT uptake in bone marrow is caused by a combination of both neoplastic and normal hematopoietic cells, the correlation of 18F-FLT uptake in bone marrow and leukemic blast infiltration did not reach statistical significance.     

Renal safety of CT angiography and perfusion imaging in the emergency evaluation of acute stroke

BACKGROUND AND PURPOSE: Multimodal CT imaging with contrast-enhanced CT angiography (CTA) and CT perfusion (CTP) is increasingly being used to guide emergency management of acute stroke. However, little has been reported about the safety of intravenous contrast administration associated with these studies in the acute stroke population, including cases in which baseline creatinine values are unknown. We investigated the incidence of contrast-induced nephropathy (CIN), defined as a 25% or more increase in baseline creatinine levels within 72 hours of contrast administration and chronic kidney disease in patients receiving CTA±CTP at our regional stroke center.MATERIALS AND METHODS: We analyzed 198 patients who underwent contrast CT studies for evaluation of acute ischemic or hemorrhagic stroke at our center (2003–2007). Through retrospective chart abstraction, we analyzed serial creatinine levels (baseline to day 3) and later values (≥day 4) where available. The incidences of CIN and/or chronic kidney disease were documented. After power analysis, CIN and non-CIN groups were compared by using the unpaired t test, Wilcoxon rank sum test, or Fisher exact test.RESULTS: None of the 198 patients developed chronic kidney disease or required dialysis. Of 175 patients with serial creatinine measurements between baseline and day 3, 5 (2.9%) developed CIN. The incidence of CIN was 2% in patients who were scanned before a baseline creatinine level was available.CONCLUSION: The incidence of renal sequelae is relatively low in acute stroke patients undergoing emergent multimodal CT scanning. Prompt CTA/CTP imaging of acute stroke, if indicated, need not be delayed in those with no history of renal impairment.

Multimodal CT scanning is increasingly being used to aid acute stroke diagnosis and management. Dynamic CT perfusion (CTP) differentiates thresholds of reversible and irreversible ischemia and, thus, helps to identify “tissue at risk” that is potentially salvageable with thrombolytic therapy.^1–4 CT angiography (CTA) allows for rapid noninvasive assessment of the intracranial and extracranial vasculature and identifies vessel occlusions or stenoses that may be amenable to acute treatment.^1–4 For intracerebral hemorrhage, CTA can identify secondary causes of hemorrhage, and, in the acute phase, the CTA “spot sign” can predict which hemorrhages are likely to expand.^5–7 Advantages of multimodal CT over MR imaging include its rapid accessibility, lower costs, shorter scanning time intervals, better patient tolerability, and higher spatial resolution.^8,9 Although it is not yet clear whether the information provided by multimodal CT improves stroke outcomes, the increasing use of these imaging methods warrants more thorough assessment of their safety profiles.Little has been reported regarding the safety of multimodal CT imaging in the acute setting. Because “time is brain” for acute stroke patients,¹⁰ some stroke centers perform such imaging immediately on patient arrival to the emergency department, often before the results of blood work (eg, creatinine) are available. The primary safety concern regarding contrast-enhanced CT is the potential development of contrast-induced nephropathy (CIN), defined as a 25% or more increase in baseline creatinine levels within 72 hours of contrast administration.^11,12 Some clinicians feel uneasy about ordering contrast studies given the potential for CIN and the difficulty in obtaining a reliable history of renal disease in acute stroke patients who are frequently incapacitated or unable to communicate. In patients with CIN, creatinine levels usually peak around days 2–3 and normalize within 2 weeks, but a small proportion go on to chronic renal failure and dialysis.^11,13 CIN has been associated with prolonged hospital stay, increased resource use, and a fivefold increase in mortality.^12,14,15This purpose of this study was to assess the renal safety of emergency multimodal CT scanning in acute stroke patients at a large regional stroke center, including those patients for whom the baseline creatinine level was not known.     

First clinical experience and 1-year follow-up with the sutureless 3F-Enable aortic valve prosthesis.

BACKGROUND: Aortic valve replacement (AVR) with extracorporeal circulation (ECC) is currently the treatment of choice for symptomatic aortic stenosis. However, patients with multiple high-risk comorbid conditions may benefit from reduced ECC time and thus, reduced myocardial ischemia, by the use of sutureless AVR. We describe the initial experience and 1-year results of our first 3F-Enable AVR implants. METHODS: Between 09/05 and 12/05, six patients (age 74+/-1.8 years; three females) with symptomatic aortic stenosis (NYHA III) underwent AVR with an equine pericardial and nitinol-stented sutureless prosthesis. For additional safety up to three stay sutures were placed. Echocardiography was performed preoperatively, intraoperatively, at 6- and 12-month follow-up. Clinical data, adverse events and patient outcome were recorded prospectively. RESULTS: Prosthesis sizes were 27 mm (n=3), 25 mm (n=1), 23 mm (n=1) and 21 mm (n=1). ECC time was 87+/-32 min; aortic clamp time was 56+/-24 min. Prosthesis deployment time was 148 +/- 173 s. There were no intraoperative deaths or complications. At 12-month follow-up mean pressure gradients (MPG) were 6.8+/-3.5 mmHg and aortic valve area (AVA) was 2.2 +/- 0.5 cm(2). One patient underwent successful redo AVR after 8 months due to severe paravalvular leakage (PVL), and one patient died due to lung cancer 10 months after surgery. At 12 months follow-up four out of six patients are alive and asymptotic (NYHA I) with the 3F-Enable aortic valve prosthesis, however, one patient showed mild paravalvular leakage. CONCLUSIONS: These first 1-year follow-up data suggest the feasibility of this new concept of sutureless aortic valve implantation. However, severe aortic insufficiency at 8 months and paravalvular leakage at 1-year follow-up should prompt further procedural and device enhancements.     

Spontaneous rupture of hepatic artery aneurysm associated with polyarteritis nodosa

Polyarteritis nodosa (PAN) is a vasculitis, which often involves small and medium sized visceral arteries. This condition may result in multifocal aneurismal formation and end-organ damage. Uncommonly, PAN may present with rupture of hepatic artery aneurysms. Here, we report a rare case of a ruptured intrahepatic aneurysm associated with PAN. A 79-year-old woman presenting with abdominal pain had CT scan of the abdomen, which revealed hematoma in the right hepatic lobe. Visceral angiogram confirmed pseudo-aneurysm of a right hepatic arterial branch, and this was managed with endovascular coil embolization. The diagnosis of PAN was made and corticosteroid therapy was initiated. We also performed a literature review to define this condition's demographics, clinical presentations, and appropriate management. The review revealed 17 published cases of ruptured PAN-related intrahepatic aneurysms. We conclude that unexplained findings of visceral arterial aneurysms should prompt investigations for vasculitis as the etiology.     

Splanchnic artery aneurysms and pseudoaneurysms: transcatheter embolization

Over the past 7 years, eight patients with splanchnic artery aneurysms and pseudoaneurysms were studied and treated. Transcatheter embolization resulted in occlusion of the lesions in all eight patients. Potentially risky and difficult surgery was avoided completely in four patients. Three patients had elective surgery at a later date when their condition was more stable. The remaining patient had definitive surgery after embolization. Transcatheter embolization should be the initial treatment of choice in splanchnic artery aneurysms and pseudoaneurysms.     

Impact of clinical history on fracture detection with radiography

The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information.     

Optic canal decompression: a cadaveric study of the effects of surgery

PURPOSE: To simulate a transphenoidal medial optic canal decompression and determine the anatomic effect on the optic nerve. METHODS: A medial optic canal decompression was performed on 5 cadaveric optic canals within 12 hours of death. Two canals were decompressed under direct visualization and 3 were decompressed by a transphenoidal endoscopic approach. The optic canal was subsequently removed en bloc, beginning at the annulus of Zinn and extending to the optic chiasm. Each specimen was processed and examined grossly. Serial coronal step sections of the entire length of the intracanalicular optic nerve were assessed histologically. RESULTS: Microscopic examination of the intracanalicular portion of optic nerve revealed incision in an extraocular muscle at the annulus, incomplete bone removal, fraying of the dural sheath, incomplete dural/arachnoid release, and incision in the pia and optic nerve. CONCLUSIONS: Transphenoidal medial wall decompression of the optic nerve canal with dural sheath opening may induce physical damage to the nerve. Any hypothetical value in dural-arachnoid sheath opening must be weighed against the potential for harm to the optic nerve caused by the surgical intervention.