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Biomedical subjects

J Wessling

Publications and source records attributed to J Wessling.

9 recordsLinked to original sources

Recurrent obscure gastrointestinal bleeding caused by aorto-enteric fistula.

Aorto-enteric fistulas are rare but serious clinical conditions that may arise as a complication following abdominal aortic surgery. Clinical symptoms in affected patients range from obscure recurrent gastrointestinal bleeding and intermittent unexplained fever attacks to fulminant hematochezia and rapid exsanguination. A high degree of clinical alertness and suspicion is critical for both accurate diagnosis and timely surgical therapy in these patients. This case report describes a patient who was referred to our department six months after abdominal aortic surgery. The patient presented with septic illness and episodes of obscure gastrointestinal bleeding. Diagnostic work-up revealed a retroperitoneal infection of the aortic graft. A false aneurysm led to recurrent duodenal bleeding, which was accompanied by perforation of the obliterated aortic graft into the cecum. After immediate surgical repair, the patient recovered and continues to do well. We present a brief review of the current literature on this entity, outlining different surgical strategies and their outcomes.

Arterio-Arterial Fistula↗

[Multi-slice spiral CT of the abdomen in oncological patients: influence of table support and detector configuration on image quality and radiation exposure].

PURPOSE: To evaluate the image quality and radiation exposure of different spiral CT scanning parameters for routine staging examination of the abdomen in oncologic patients using a multi-slice CT scanner. METHODS/MATERIALS: Examination of 40 patients in 4 groups on a multi-slice CT scanner (Somatom VolumeZoom, Siemens AG, Forchheim). Functional detector width (4 x 2.5, 4 x 5 mm) and pitch (table feed in relation to collimated slice width) were varied (3 and 5). Tube voltage (120 kV), effective tube current (160 mAs), slice-thickness (6 mm), increment (4 mm), kernel (B 30), and contrast injection parameters were kept constant. Axial images were assessed by three radiologists regarding delineation of anatomic structures, artifacts, and overall image quality. RESULTS: Significantly reduced image quality especially due to artifacts was observed using a 5 mm detector configuration with a pitch of 5 (scan time 9 sec). Image quality was rated best for a 2.5 mm detector configuration with a pitch of 3 and a scan time of 28 sec. The effective dose was independent of the pitch. However, the mean effective dose was 9% higher using the smaller detector configuration (9.9 mSv vs 10.9 mSv). CONCLUSIONS: For routine staging CT of the abdomen use of a 4 x 2.5 mm detector configuration with a pitch between 3 and 5 is recommended. A 4 x 5 mm detector configuration using overlapping data acquisition can also be recommended, but additional thin slice reformations are not possible.

Abdominal Neoplasms↗

Colorectal polyps: Detection with multi-slice CT colonography.

PURPOSE: To compare the performance of virtual and conventional colonoscopy for the detection of colorectal polyps using a multislice spiral CT scanner (MSCT). MATERIALS AND METHODS: 48 patients (20 women, 28 men, mean age 61.5 years) with clinical indication for conventional colonoscopy were prospectively studied using a MSCT (Somatom Volume Zoom, Siemens, Forchheim). Examination was performed after standard oral preparation for colonoscopy and colonic distension with room air and i. v. butylscopolamin. Images were obtained in prone and supine position using a detector configuration of 4 x 1 mm, a table feed of 5 mm/rotation at 140 mAs and 120 kV. Slice thickness and reconstruction increment were 3 and 1.5 mm, respectively. CT data were assessed by two blinded radiologists on a Vitrea workstation (Vital Images, USA) using a software with multiplanar and volume-rendering capabilities. RESULTS: 33 patients had normal findings on conventional colonoscopy. In 15 patients a total of 30 polyps and one carcinoma with stenosis were identified. MSCT-colonography identified the carcinoma and 23 polyps (77 %). 3 of 3 polyps were 10 mm or more (100 %), 6 of 7 were 5.1 to 9.9 mm (86 %) and 14 of 20 were 5 mm or smaller (70 %). There were 13 false positive findings for polyps (10 lesions < 6 mm in 5 patients) and no false positive finding of carcinoma. CONCLUSIONS: MSCT colonography allows accurate detection of polyps larger than 10 mm. Compared to published results of single-slice CT, multislice CT colonography increases the rate of detection of small colorectal polyps in particular. However, false positive results still remain a problem.

Colonic Diseases↗

Multislice CT angiography of the iliac arteries in the presence of various stents: in vitro evaluation of artifacts and lumen visibility.

RATIONALE AND OBJECTIVES: To evaluate the imaging characteristics of various iliac artery stents and stent-grafts in a multislice, computed tomography angiography (MSCTA) phantom study. METHODS: Twelve types of stents and three stent-grafts made of different materials (steel, nitinol, tantalum, cobalt-based alloy) were implanted in plastic tubes with an 8-mm inner diameter filled with iodinated contrast medium diluted to 200 HU. To evaluate the influence of scan parameters on artifacts, the Palmaz stent (as one example) was scanned with a four-slice scanner (Siemens VolumeZoom) with different detector collimations and pitches. All other stents were examined with a collimation of 4 x 1 mm and a table feed of 4 mm/rotation. Axial images and multiplanar reformations were evaluated regarding artifact size, lumen visibility, and intraluminal attenuation values. RESULTS: Higher pitch values caused more pronounced artifacts. Image quality and delineation of the stent struts improved with thinner detector collimation. The size of the stent-related artifacts and the visibility of the stent lumen depended on the underlying stent material and design. Pronounced artifacts, resulting in an insufficient delineation of the stent lumen, were caused by the Strecker tantalum stent and the Zenith stent. Moderate artifacts were caused by the Wallgraft, Passager, Palmaz P 395 and P 424, Bridge, Perflex, and ZA stents. Some artificial lumen narrowing but good lumen delineation was seen with the Strecker nitinol, Symphony, Memotherm, SMART, Corinthian, and Wallstent stents. CONCLUSIONS: Scanning parameters, stent material, and stent design influence lumen assessability and image quality in MSCTA. Detailed lumen assessment is impossible in the Strecker tantalum and Zenith stents and limited in the Wallgraft, Passager, Palmaz P 395 and PS 424, Bridge, Perflex, and ZA-stent stent-grafts but feasible in all other examined products.

Angiography↗

A natural apolipoprotein A-I variant, apoA-I (L141R)Pisa, interferes with the formation of alpha-high density lipoproteins (HDL) but not with the formation of pre beta 1-HDL and influences efflux of cholesterol into plasma.

ApoA-I(L141R)Pisa is a naturally occurring apolipoprotein A-I variant that causes virtual absence of HDL in hemizygotes and hypoalphalipoproteinemia with half-normal levels of HDL-cholesterol in heterozygotes. In this study we analyzed the distribution of HDL subclasses in plasmas of four hemizygotes for this mutation. We also investigated the abilities of these plasmas to esterify cholesterol and to promote cholesterol efflux. Residual apoA-I-containing lipoproteins in plasmas of hemizygotes for apoA-I(L141R)Pisa correspond to pre beta 1-LpA-I and small alpha-LpA-I. Unlike normal pre beta 1-LpA-I, pre beta 1-LpA-I of apoA-I(L141R)Pisa hemizygotes was not converted into a larger alpha-migrating particle. Plasmas of apoA-I(L141R)Pisa hemizygotes were significantly reduced in their activity to esterify cholesterol in either endogenous or exogenous lipoproteins. Cholesterol efflux capacity was significantly lower than that of normal plasma. Efflux of [3H] cholesterol from radiolabeled fibroblasts into apoB-depleted plasma of normal probands was biphasic with fast cholesterol efflux occurring in the first minute. Thereafter, cholesterol efflux was slow and unsaturable. After incubation with radiolabeled fibroblasts, efflux values of [3H]cholesterol into apoB-depleted plasma from normal controls and from apoA-I(L141R)Pisa hemizygotes were indistinguishable at 1 min. Longer incubations with apoB-free plasma from apoA-I(L141R)Pisa hemizygotes did not, however, lead to the unsaturable increase in cholesterol efflux that was observed during incubations with apoB-free plasma of normolipidemic probands. Pre beta 1-LpA-I of apoA-I(L141R)Pisa hemizygotes took up significantly less cell-derived [3H]cholesterol than pre beta 1-LpA-I of normal donors. We conclude that apoA-I(L141R)Pisa interferes with the formation of lipid-rich alpha-HDL but not with that of lipid-poor pre beta 1-LpA-I. Very low concentrations of alpha-HDL in plasmas of apoA-I(L141R)Pisa hemizygotes combined with reduced LCAT activity cause a decrease of the slow, unspecific, and LCAT-dependent components of cholesterol efflux into plasma.

Animals↗

Compound heterozygosity for a structural apolipoprotein A-I variant, apo A-I(L141R)Pisa, and an apolipoprotein A-I null allele in patients with absence of HDL cholesterol, corneal opacifications, and coronary heart disease.

BACKGROUND: The concentration of HDL cholesterol is inversely correlated with the risk of coronary heart disease (CHD). Some rare mutations in the apolipoprotein (apo) A-I gene are associated with low levels of HDL cholesterol. Their association with cardiovascular risk is controversial. METHODS AND RESULTS: We studied the molecular defects underlying corneal opacities and absence of HDL cholesterol in three brothers and a sister. In a family study, the importance of these defects for lipid metabolism and manifestation of coronary heart disease was investigated. The frequency of these apo A-I defects was assessed by genotype and phenotype analysis of 477 DNA- and plasma samples, respectively, from the population. The four patients were compound heterozygotes for a null allele and a missense mutation in the apo A-I gene that leads to a leucine-->arginine substitution at residue 141 [apo A-I(L141R)Pisa]. Heterozygotes for either the null allele or the structural variant had half-normal concentrations of HDL cholesterol and apo A-I compared with unaffected family members. Apo A-I(L141R)Pisa was detected in one more unrelated subject. Coronary angiography of the four compound heterozygotes revealed the presence of CHD in all male patients, whose ages ranged between 45 and 52 years. They presented with additional risk factors, including elevated LDL cholesterol levels, obesity, and arterial hypertension. Despite complete HDL deficiency and hypercholesterolemia, CHD was absent in the 51-year-old premenopausal sister. CONCLUSIONS: Apo A-I deficiency may lead to premature atherosclerosis if present in conjunction with additional cardiovascular risk factors.

Adolescent↗

Multislice cardiac spiral CT evaluation of atypical hypertrophic cardiomyopathy with a calcified left ventricular thrombus.

We report a case of a 43-year-old male patient with an atypical nonobstructive hypertrophic cardiomyopathy and a calcified left ventricular thrombus, and present results of multislice computed tomography (MSCT) using retrospective electrocardiograph gating, which is a new modality in cardiac imaging. Obtaining virtually motion-free images with a temporal resolution of 250 ms in an optimized heart scan MSCT allows functional imaging with evaluation of impaired systolic and diastolic left ventricular wall motion.

Adult↗