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PubMed2006

Rounded atelectasis with atypical computed tomography findings.

Rounded atelectasis is atelectasis of the peripheral part of the lung, typically in contact with thickened pleura, featuring characteristic computed tomography findings. In this case, a 61-year-old man with history of asbestos exposure presented with a right-middle-lobe nodule on chest radiograph, with computed tomography findings suspicious for neoplasm. The patient underwent surgical resection, which revealed rounded atelectasis. Our case raises a question about the sensitivity of radiographic criteria used in identifying rounded atelectasis, and it emphasizes the need to keep rounded atelectasis in the differential diagnosis of a single pulmonary nodule in a patient with a history of asbestos exposure.

Diagnosis, Differential↗
PubMed1998

Diagnostic value of spiral-CT angiography in comparison with digital subtraction angiography before and after peripheral vascular intervention.

To evaluate spiral-computed tomography (CT) angiography in primary diagnosis and/or in noninvasive follow-up after vascular intervention, we compared spiral-CT angiography and conventional angiography before and after vascular intervention. Helical-CT examinations before and after percutaneous transluminal angioplasty (PTA) or stent implantation were performed in 10 patients (mean age 63 years) with symptomatic peripheral arteriosclerotic disease. Stenoses were located in the iliac, femoral, or popliteal artery. CT examinations were done with a spiral-CT in double detector technique (CT Twin, Elscint). The parameters were as follows: slice thickness: 5.5 mm, increment: 2.7 mm, pitch: 1.5, contrast medium: 150 mL, flow rate: 2.5 mL/second, delay: 30 seconds. For evaluation, transverse planes as well as maximum intensity projections and 3-D reconstructions were used. The possible scan length reached from the aortic bifurcation down to about 10 cm below the ankle trifurcation. Preinterventional digital subtraction angiography (DSA) was superior to CT angiography (CTA: 94%, maximum intensity projection [MIP] alone: 65%), although high-grade stenoses were detected by both methods. After intervention, a resolved stenosis and improved peripheral flow could be detected by helical-CT as well as by intraarterial angiography in every patient (100%). In the primary diagnosis of vascular changes, intraarterial DSA remains the method of choice. Nevertheless, spiral-CT angiography shows comparable results after percutaneous intervention and becomes a noninvasive alternative in the postinterventional follow-up.

Angiography↗
PubMed1976

Centrol and peripheral correlates of anxiety: a comparative study.

Physiological measurements and mood ratings were recorded in 32 normal subjects at rest and under differing stressful conditions designed to induce anxiety. The physiological measurements were recorded simultaneously using a polygraph and on-line computer analysis; these comprised the peripheral measurements of pulse rate, skin conductance, spontaneous fluctuations in skin conductance, respiratory rate, and finger tremor, and the central measurements of resting electroencephalogram and averaged evoked potentials to an auditory stimulus. Mood rating were recorded using analogue rating scales, the 16 scores obtained being reduced to three mood factors. Correlations were calculated between the mood factors and each of the physiological measurements. The highest correlations were between the anxiety factor and the central measurements, particularly the proportion of electroencephalographic activity between 7.5 and 13.0 Hz, and the latencies of the secondary components of the evoked response. The peripheral measurements correlated rather less well with mood, but skin conductance and fluctuations in skin conductance, pulse rate, and tremor near the peak frequency of 9 Hz all correlated significantly with anxiety. Only two correlations were greater than 0.4, illustrating that no measure was a specific index of anxiety. Refinement of central rather than peripheral measurements is likely to lead to closer correlations with anxiety and other mood states.

Acoustic Stimulation↗
PubMedDate not supplied

Computer analysis of optokinetic nystagmus in patients with spontaneous nystagmus of peripheral vestibular origin.

The bias of slow phase velocity (SPV) of optokinetic nystagmus (OKN) caused by an acute labyrinthine lesion was examined in 8 patients using differnet optokinetic stimulus velocities. In all patients a directional preponderance of OKN-SPV was found corresponding to spontaneous nystagmus. This was due to enhancement of nystagmus SPV to the side of the lesion and depression of SPV in the opposite horizontal direction. The preponderance of OKN on the average increased with the intensity of spontaneous nystagmus and decreased along with recovery. These vestibularly induced differences in OKN-SPV range up to 70%. A differentiation is discussed between OKN preponderances caused by labyrinthine lesions and brain stem lesions.

Acute Disease↗
PubMed1990

Irregular geometries in normal unmyelinated axons: a 3D serial EM analysis.

Axons have generally been represented as straight cylinders. It is not at all uncommon for anatomists to take single cross-sections of an axonal bundle, and from the axonal diameter compute expected conduction velocities. This assumes that each cross-section represents a slice through a perfect cylinder. We have examined the three-dimensional geometry of 98 central and peripheral unmyelinated axons, using computer-assisted serial electron microscopy. These reconstructions reveal that virtually all unmyelinated axons have highly irregular axial shapes consisting of periodic varicosities. The varicosities were, without exception, filled with membranous organelles frequently including mitochondria, and have obligatory volumes similar to that described in other neurites. The mitochondria make contact with microtubules, while the other membraneous organelles were frequently found free floating in the cytoplasm. We conclude that unmyelinated axons are fundamentally varicose structures created by the presence of organelles, and that an axon's calibre is dynamic in both space and time. These irregular axonal geometries raise serious doubts about standard two dimensional morphometric analysis and suggest that electrical properties may be more heterogeneous than expected from single section data. These results also suggest that the total number of microtubules contained in an axon, rather than its single section diameter, may prove to be a more accurate predictor of properties such as conduction velocity. Finally, these results offer an explanation for a number of pathological changes that have been described in unmyelinated axons.

Animals↗
PubMed1988

Concurrent lumbar spinal stenosis and peripheral vascular disease. A report of nine patients.

Intermittent claudication from peripheral vascular disease is sometimes difficult to distinguish from neurogenic claudication secondary to lumbar spinal stenosis. Of 172 patients with symptoms of claudication and lumbar spinal stenosis proved by myelography or computed tomography (CT), nine had peripheral vascular disease identified with ultrasonography and arteriography. All of the nine patients had a laminectomy performed to decompress the narrow spinal canal, and two had an additional posterolateral fusion. Two patients were treated with an excision of their abdominal aortic aneurysm, while one of those patients later required a bypass graft for iliac stenosis. One patient had had an aortofemoral bypass graft, one a femoropopliteal graft, and one a lumbar sympathectomy. Follow-up study ranged from three to eight years, with an average of five years after their last surgical procedure. Paresthesias generally dissipated after the spinal surgery. The cramping-type discomfort associated with walking was not easily attributed either to vascular or a neurogenic etiology. Five patients had initial weakness, which invariably improved. A secondary etiology contributing to claudication must be excluded in those patients with persistent discomfort following previous lumbar spinal or vascular surgery for arterial insufficiency.

Aged↗
PubMed2003

CT findings in peripheral T-cell lymphoma involving the gastrointestinal tract.

PURPOSE: To evaluate whether computed tomography (CT) accurately depicted gastrointestinal tract involvement in peripheral T-cell lymphoma (PTCL). MATERIALS AND METHODS: CT scans were retrospectively reviewed in 14 patients with pathologically proved PTCLs of the gastrointestinal tract for the following considerations: sites, patterns of involvement (ie, morphologic features, bowel wall thickness or mass size, and contrast enhancement pattern), and ancillary findings at other sites (ie, lymphadenopathy, bowel perforation, and involvement of other organs). RESULTS: PTCL involved the stomach in three patients, the small intestine in eight, both the stomach and the small intestine in one, and the sigmoid colon in two; multifocal involvement was seen in three (21%) patients. CT failed to demonstrate the bowel lesions in three of 14 patients. At CT, 11 patients had gastric or bowel wall thickening (n = 10) and a polypoid mass (n = 1). In 10 patients, the gastric or bowel wall thickening was mild (<1 cm) in six, moderate (1-2 cm) in three, and severe (>2 cm) in one. Lymphadenopathy was noted in nine (64%) patients, with the nonbulky type in eight and the bulky type in one. Bowel perforation occurred in four (29%) patients. Other organs were involved in eight (57%) patients. CONCLUSION: CT can depict PTCL involving the gastrointestinal tract if it is not confined to the mucosa. There is a tendency toward preferential jejunal or duodenal involvement, as well as bowel perforation.

Adult↗
PubMed2005

Lung infection due to opportunistic fungus, Phialemonium obovatum, in a bone marrow transplant recipient: an emerging infection with fungemia and Crohn disease-like involvement of the gastrointestinal tract.

We report the first case of Phialemonium obovatum fungemia with subsequent caseating granulomatas in the lung and Crohn disease-like involvement of the gastrointestinal tract in a bone marrow transplant recipient. This phaeoid fungus has been rarely described as an opportunistic infection in immunosuppressed patients. The patient was diagnosed with chronic myelogenous leukemia and underwent subsequent peripheral bone marrow transplant. After 6 months, he developed graft-versus-host disease of the skin and liver with fever and severe diarrhea. Fecal bacterial cultures and cytomegalovirus serologies were negative. Computed tomographic scan showed a peripheral pulmonary mass. A lung wedge biopsy of the lesion showed septate branching hyphae (4-5 microm in diameter) with terminal globular structures (10 microm in diameter). The hyphae were similar in width to that of an Aspergillus species but had a more moniliform appearance. Blood cultures grew a pure culture of P. obovatum. He was treated with amphotericin B and itraconazole for 6 months without remission of the diarrhea. Biopsies of the stomach, colon, and rectum showed granulomatous inflammation with marked crypt distortion simulating Crohn disease. In retrospect, the fungus was found to be resistant to both of the aforementioned drugs and susceptible to voriconazole and posaconazole. The gastrointestinal findings raise the possibility of further dissemination of a partially treated Phialemonium infection.

Amphotericin B↗
PubMed1994

[A method for determining pulse wave transmission time].

Analysis of the transit time of a pulse wave is a possibility for the continuous observation of the changes in blood pressure activity. With invasive procedures, the interval between two notable events on pressure pulse waveforms, which is known as the pulse transit time, is often calculated. Using the second heart sound, the pre-ejection period and the left-ventricular ejection time (systolic time interval) are computed in order to be able to exclude the effect of haemodynamic parameters on aortic pressure increase. Since the use of noninvasive procedures excludes computation of the systolic time interval, and a phonocardiography is also often lacking, a method of relatively quickly determining the time interval between the R-wave of the ECG and the peripheral pulse was developed. The computed pulse transmission time is suitable for studying phasic events and their effects on the mean blood pressure.

Blood Pressure↗
PubMed1997

Peripheral cholangiocarcinoma of the liver: two-phase spiral CT findings.

PURPOSE: To determine characteristic features of peripheral cholangiocarcinoma on two-phase spiral computed tomographic (CT) scans. MATERIALS AND METHODS: Thirty-four patients with peripheral cholangiocarcinoma underwent two-phase spiral CT. Hepatic arterial phase and portal venous phase images were obtained 30 and 65 seconds, respectively, after the start of contrast material infusion. RESULTS: Thin, mild, incomplete rimlike contrast enhancement at the tumor periphery was seen on CT scans from both phases in 23 patients. Thick, continuous rimlike contrast enhancement and marked homogeneous contrast enhancement were present on scans in four patients and one patient, respectively. No definite contrast enhancement pattern was seen on scans in six patients. Other findings included increased lobar or segmental hepatic attenuation in adjacent normal liver during the arterial phase (n = 10), markedly low attenuation with amorphous areas of slightly high attenuation in the tumor during both phases (n = 33), internal septumlike linear structures (n = 8), narrowing or obstruction of the portal vein as it traversed the tumor (n = 16), and a patent hepatic vein (n = 4). CONCLUSION: Thin, mild, incomplete rimlike contrast enhancement at the tumor periphery and markedly low intratumoral attenuation with amorphous areas of slightly high attenuation during both scanning phases are typical findings of peripheral cholangiocarcinoma.

Bile Duct Neoplasms↗
PubMed2004

MDCT-imaging of peripheral arterial disease.

With the design and development of advanced computed tomography (CT) techniques and applications, like the newest generation of 16-detector-row CTs, CT angiography of the lower limb becomes a feasible tool for imaging peripheral vascular disease. Due to several advantages, compared with conventional digital subtraction angiography (DSA), including minimal invasiveness, CT angiography competes against diagnostic DSA in several clinical situations. 16-DCT offers the possibility to acquire thin slices from the diaphragm to the ankle in less than 40 sec. Easily, a data set of 800 to 1200 transverse slices may be created. To use transverse reconstructions alone to read these volumetric data sets is not appropriate. Powerful post-processing tools for volumetric analysis are required so that routine interpretation can be performed as efficiently and accurately as transverse section review. Because of its widespread availability and applicability, CT angiography of the lower extremities may be applied to patients in a pre- or post-procedural situation and also serves as a first line modality in patients with acute onset of clinical symptoms. Although multidetector CT arteriography is rapidly achieving clinical acceptance, further studies need to be performed to fully evaluate the clinical value of this method of peripheral arterial imaging. This article reviews the current status of multidetector CT peripheral arteriography, including indications, technical details, image post-processing, radiation exposure, and clinical results.

Angiography↗
PubMed2006

Cushing's syndrome secondary to bronchopulmonary carcinoid tumor: report of two cases and literature review.

Bronchopulmonary carcinoid tumors have been associated with a variety of endocrine disorders including Cushing's syndrome (CS), which is caused by ectopic adrenocorticotrophic hormone (ACTH) secretion. We report two cases of CS secondary to bronchopulmonary carcinoid tumors. The first patient, a 29-year-old woman, presented hypokalemia, high serum ACTH level and high free-urinary cortisol, raising suspicion of an ectopic ACTH syndrome. Chest computed tomography and Octreoscan showed a peripheral nodule in the left-superior lobe of the lung. After lobectomy, a typical bronchopulmonary carcinoid was diagnosed. The second patient, a 16-year-old boy, presented "moon face" and progressive asthenia, high serum ACTH level and high free-urinary cortisol, raising the same hypothesis. Chest computed tomography and Octreoscan showed a peripheral nodule in the middle lobe. After lobectomy, an atypical bronchopulmonary carcinoid was diagnosed. Both cases had IA stage (T1N0M0), positively immunostaining for chromogranin and ACTH. Neither of these patients had hypophysary microadenomas, adrenal adenomas or recurrence of CS after surgical treatment, demonstrating that CS was caused solely by the presence of the bronchopulmonary carcinoid tumors.

Adolescent↗
PubMed1979

[On the peripheral refraction of the human eye (author's transl)].

As the measurements of the peripheral refraction of the living human eye published till now point out a confusing abundance of variants but no clear results, the peripheral refraction of fictitious model eyes is computed to find out which components influence the refraction and how they do it. Then for some special selected representative eyes the peripheral refraction and the astigmatism are computed and the results analyzed. The result consists in three typical refractioncurves which can be reduced to simple rules. This paper intends to stimulate future experiments on exactly defined conditions.

Astigmatism↗
PubMed1995

Small peripheral lung carcinoma evaluated with incremental dynamic CT: radiologic-pathologic correlation.

PURPOSE: To correlate incremental dynamic computed tomographic (CT) and pathologic findings in peripheral lung cancer. MATERIALS AND METHODS: Lung lesions smaller than 3 cm in diameter were evaluated in 18 patients. CT values of the inner area of the nodule at plain CT and at 30 seconds, 2 minutes, and 5 minutes after administration of nonionic contrast material were calculated with incremental dynamic CT. Maximum attenuation was compared with pathologic type of lung carcinoma and with number of vessels and distribution of elastic fibers in the pathologic specimen. RESULTS: Enhancement of all lesions was statistically significant (P < .0001). Maximum attenuation of lung carcinomas correlated positively with number of small vessels (diameter, 0.02-0.10 mm) (r = .77). Distribution of elastic fibers in the tumoral interstitium correlated with maximum attenuation (P = .04 between grades 1 and 3) and with number of small vessels (P = .01 between grades 1-3; P = .008 between grades 1 and 3). CONCLUSION: Enhancement characteristics of lung carcinomas reflect the number of small tumoral vessels and the distribution of elastic fibers in the tumoral interstitium.

Adenocarcinoma↗
PubMed2004

Peripheral lung nodules: fluoroscopically guided video-assisted thoracoscopic resection after computed tomography-guided localization using platinum microcoils.

OBJECTIVES: We sought to test the safety and efficacy of fluoroscopically guided, video-assisted, thoracoscopic resection after computed tomography (CT)-guided localization using platinum microcoils. SUMMARY BACKGROUND DATA: Video-assisted thoracoscopic (VATS) resection of small pulmonary nodules >5 mm deep to the visceral pleura fails to locate the nodule and requires conversion to open thoracotomy in two thirds of cases. Therefore, we developed a new technique for intraoperative localization of these nodules using CT-guided placement of platinum microcoils. This study tests the safety and efficacy of this technique in a Phase I human study. METHODS: Twelve patients with undiagnosed growing pulmonary nodules <20 mm were marked preoperatively using percutaneously placed CT-guided platinum microcoils. The coil was deployed adjacent to the nodule with the distal end of the coil placed deep to the nodule and the superficial end coiled on the pleural surface. The nodule and coil were excised using endostaplers guided by VATS and fluoroscopy. Histopathologic diagnosis was performed immediately after resection. RESULTS: CT-guided microcoil localization was successful in all patients. A small hemothorax and a pneumothorax requiring a chest tube occurred in 2 patients. Mean distance from visceral pleura to the deep edge of the nodule was 30.9 +/- 15.4 mm. VATS resection of the nodules (size = 11.8 +/- 3.2 mm) was successful in all patients. Mean microcoil localization, fluoroscopy, and operative times were 42 +/- 14, 3.1 +/- 2.0, and 67 +/- 27 minutes. A diagnosis of primary nonsmall cell bronchogenic carcinoma was made in 6 patients who then received a completion lobectomy. Six patients (hamartoma: 2, reactive lymph node: 1, bronchoalveolar cell carcinoma: 2, metastatic sarcoma: 1) did not receive further resections. CONCLUSIONS: Preoperative localization of pulmonary nodules using percutaneous CT-guided platinum microcoil insertion combined with operative fluoroscopic visualization is a safe, effective technique that increases the success rate of VATS excision.

Female↗
PubMed1998

5-Alkyl-2-[(methylthiomethyl)thio]-6-(benzyl)-pyrimidin-4-(1H)-ones as potent non-nucleoside reverse transcriptase inhibitors of S-DABO series.

Novel dihydroalkoxybenzyloxopyrimidine (S-DABO) derivatives targeting the non-nucleoside inhibitor (NNI) binding site of human immunodeficiency virus (HIV) reverse transcriptase (RT) have been synthesized using a novel computer model for the NNI binding pocket and tested for their RT inhibitory activity in cell-free assays using purified recombinant HIV RT as well as for their anti-HIV activity in HTL VIIIB-infected peripheral blood mononuclear cells. Our computational approach allowed the identification of several ligand derivatization sites for the generation of more potent S-DABO derivatives. Our lead S-DABO derivative, 5-isopropyl-2-[(methylthiomethyl)thio]-6-(benzyl)-pyrimidin-4-(1H)-one (compound 3), elicited potent anti-HIV activity with an IC50 value of less than 1nM for inhibition of HIV replication without any evidence of cytotoxicity and an unprecedented selectivity index of > 100,000.

Anti-HIV Agents↗
PubMed2006

Pubertal timing is an independent predictor of central adiposity in young adult males: the Gothenburg osteoporosis and obesity determinants study.

The role of puberty and normal variations in pubertal timing for the development of obesity in men is unclear. The aim of the current study was to investigate the impact of pubertal timing and prepubertal BMI (kg/m(2)) for young adult BMI and fat mass distribution. Detailed growth charts from birth to age 18-20 years were retrieved for the men participating in the population-based Gothenburg Osteoporosis and Obesity Determinants study. Age at peak height velocity (PHV) and BMI at age 10 years were estimated for 579 subjects, and PHV was used as an assessment of pubertal timing. The fat mass characterization and distribution were analyzed using dual X-ray absorptiometry and peripheral as well as abdominal computed tomography at age 18.9 +/- 0.5 years. We demonstrate that age at PHV is an independent negative predictor of young adult BMI and whole-body fat mass. Interestingly, age at PHV is an independent negative predictor of central, but not peripheral, fat mass. In contrast, BMI at 10 years of age predicts both central and peripheral subcutaneous fat mass. In conclusion, we demonstrate that early pubertal onset specifically predicts a central fat mass distribution, while a predominantly subcutaneous obese phenotype is strongly predicted by a high prepubertal BMI.

Absorptiometry, Photon↗
PubMed1984

Peripheral limitations to exercise.

We present a computer simulation of a two-compartment model of the systemic circulation which demonstrates how this model can be used to understand the mechanism(s) for the maximal exercise cardiac output (Q). The model consists of two parallel vascular channels, the splanchnic channel (all blood draining through the hepatic veins) and the peripheral channel (all other vascular beds). The distinguishing characteristic of each channel is the product of its venous compliance and venous resistance. Model parameters for the human circulation were estimated from similar parameters obtained directly from animal experiments. "Exercise" was achieved by decreasing the compliance of both channels to 40% of their initial value and by redistributing the Q such that the fraction of Q perfusing the splanchnic channel fell from 38 to 5%, while that perfusing the peripheral channel (skeletal muscles) increased from 62 to 95%. These combined changes increased Q from 4.4 to 22.0 l X min-1 and suggest that maximal adjustments of the two-compartment model parameters lead to a prediction of a maximal Q that approaches the maximal Q usually obtained by humans during exercise.

Blood Circulation↗