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At least 847 records · Page 47Linked to original sources
PubMed1993

Positive bowel contrast agent for MR imaging of the abdomen: phase II and III clinical trials.

PURPOSE: To evaluate the efficacy and safety of two dose levels of an orally administered ferric ammonium citrate-based contrast agent for bowel enhancement on T1-weighted spin-echo magnetic resonance (MR) images in 222 patients with known or suspected abnormality of the upper abdomen. MATERIALS AND METHODS: Adverse reactions were graded for intensity, frequency, duration, and relationship to the contrast agent. Twelve unblinded readers compared enhanced with unenhanced images; all MR images were evaluated by two independent offsite radiologists in a blinded review. RESULTS: No statistically significant changes in mean vital signs or laboratory values were seen. Forty-eight of 220 patients (22%) reported minor side effects. The readers found increased intraluminal signal intensity and improved contrast enhancement of the gastrointestinal tract and distention and improved signal homogeneity in 101-107 cases (89%-98%) after ingestion; the blinded reviewers' findings were similar. CONCLUSION: The contrast agent provided new or additional radiologic information in 142 patients (64%), specific additional information in a detected abnormality in 46 of 142 patients (32%), and information that changed diagnosis, management, or surgical approach in 22 of 142 patients (15%).

Abdomen↗
PubMed1995

MR imaging of the abdomen with a phased-array multicoil: prospective clinical evaluation.

PURPOSE: To prospectively compare use of a phased-array multicoil and a conventional body coil in abdominal MR imaging. MATERIALS AND METHODS: Thirteen patients (seven men, six women; mean age, 55 years) underwent imaging with a phased-array multicoil and with a conventional body coil. Four pulse sequences were used: T2-weighted spin echo (SE), magnetization-prepared gradient-recalled echo (GRE), breath-hold fast SE, and echo planar (EP). RESULTS: Lesion detection improved the most on fast SE, multicoil-acquired images. Signal-to-noise ratio (S/N) increased 64% with fast SE (P = .0005) and EP (P < .0109) sequences. Contrast-to-noise ratio (C/N) doubled (P < .05) with T2-weighted SE sequences. Lesion conspicuity improved on multicoil-acquired images with all fast sequences (magnetization-prepared GRE, P = .015; fast SE, P = .002; EP imaging, P = .013). There was little difference in respiratory and vascular artifact. Depiction of most abdominal structures improved (P < .01). CONCLUSION: Use of the phased-array multicoil provides better MR images of the abdomen than does use of a conventional body coil.

Abdomen↗
PubMed1997

Small lymph nodes of the abdomen, pelvis, and retroperitoneum: usefulness of sonographically guided biopsy.

PURPOSE: To evaluate the usefulness of sonographically guided percutaneous biopsy of small lymph nodes in the abdomen, retroperitoneum, and pelvis. MATERIALS AND METHODS: From May 1995 through January 1997, 35 sonographically guided lymph node biopsies were performed in 34 patients. All biopsies were performed with a 20- (n = 18) or 22-gauge (n = 10) self-aspirating needle alone or in combination (n = 7). To determine the amount of compression achieved with the transducer, the skin-to-lesion distance on reference computed tomographic (CT) scans was compared with that on sonograms. A biopsy was considered successful if a specific benign or malignant diagnosis was rendered by the pathologist. RESULTS: Of 35 sonographically guided biopsies, 30 (86%) were successful. Diagnoses included 26 (74%) cases of carcinoma, three (9%) cases of benign reactive lymphocytosis confirmed at open biopsy, and one (3%) case of a lymph node with a positive acid-fast bacilli stain. The average lymph node diameter was 2.1 cm (range, 0.9-4.3 cm). With sonography, a mean of 2.5 needle passes (range, 1-5) were made per biopsy. Transducer compression reduced the skin-to-lesion distance from an average of 8.8 cm (at CT) to 4.5 cm. CONCLUSION: Sonographic guidance seems to provide a reasonable alternative to CT in biopsy of small abdominal, pelvic and retroperitoneal lymph nodes.

Abdomen↗
PubMed2000

Breath-hold contrast-enhanced three-dimensional MR angiography of the abdomen: time-resolved imaging versus single-phase imaging.

PURPOSE: To evaluate a technique for time-resolved breath-hold contrast material-enhanced three-dimensional magnetic resonance (MR) angiography of the abdomen. MATERIALS AND METHODS: In a prospective study, 43 patients underwent time-resolved MR angiography (acquisition time per data set, 7 seconds). The patients also underwent single-phase high-spatial-resolution MR angiography (acquisition time, 27 seconds) (n = 6), conventional angiography (n = 7), or both (n = 30). No bolus timing study was performed for time-resolved MR angiography. Image quality (presence of artifacts, ability to prevent venous overlap on arterial phase images, contrast enhancement) and demonstration of anatomic variants (renal arterial and venous variants, vena caval anomaly, visceral arterial variants) and vascular diseases were assessed. RESULTS: Time-resolved MR angiographic images were characterized by fewer and less severe artifacts, less overlap of enhancing veins, and better contrast enhancement than were single-phase MR angiographic images (P < .05). The mean sensitivity and specificity were 90% (nine of 10) and 100% (1 73 of 1 73), respectively, for detection of arterial anatomic variants and 93% (28 of 30) and 100% (324 of 325), respectively, for detection of disease. The technique also proved to be reliable for demonstration of venous disease. CONCLUSION: In comparison with current non-time-resolved MR angiographic techniques, time-resolved MR angiography is more robust and easier to perform and allows simultaneous evaluation of arterial and venous disease.

Abdomen↗
PubMed2000

Abdomen, pelvis, and extremities: diagnostic accuracy of dynamic contrast-enhanced turbo MR angiography compared with conventional angiography-initial experience.

To determine the value of contrast material-enhanced three-dimensional turbo magnetic resonance (MR) angiography compared with conventional cut-film or digital subtraction angiography for evaluating arterial stenosis in the abdomen, pelvis, and extremities. For detection of significant stenosis, MR angiography had 91% sensitivity and 89% specificity. This technique is highly sensitive in lesion detection, but stenosis tended to be overestimated.

Abdomen↗
PubMed1975

Relative contributions of rib cage and abdomen to breathing in normal subjects.

By use of the method of Konno and Mead and the respiratory magnetometer, the partition of respired gas volumes into rib cage and diaphragm-abdomen components was accomplished in 81 normal subjects including 32 young and middle-aged men, 29 young and middle-aged women, and 20 elderly men. Studied were isovolume maneuvers and the relaxation configuration over the inspiratory capacity range, quiet tidal breathing, increased amplitudes of slow breathing, rapid inspirations and expirations, and both quiet and forceful phonation. No major differences were noted between men and women or between the young and the elderly during any respiratory acts. During quiet breathing most normal subjects are abdominal breathers when supine and thoracic breathers when upright. Rapid respiratory maneuvers were accomplished mostly through rib cage displacement suggesting that rib cage muscles are capable of more rapid action than diaphragm and abdominal muscles. Data from deep breathing and rapid maneuvers supported the view that abdominal and rib cage muscles often act to optimize the mechanical (length-tension) advantage of the diaphragm.

Abdomen↗
PubMed1985

Rib cage and diaphragm-abdomen compliance in humans: effects of age and posture.

The influence of age and posture on compliance of the rib cage (Crc) and diaphragm-abdomen (Cab) compartments of the chest wall was studied in 61 healthy adults (33 men, 28 women) aged 24-75 yr. Chest wall compliance (Cw) was measured by the weighted spirometer technique; Crc and Cab were derived from the slope of the relaxation line of the thoracoabdominal system obtained with two pairs of linearized magnetometers. While Cw was being measured, we monitored electrical activity of the abdominal external oblique muscle with a concentric needle electrode and thoracoabdominal configuration. In 52 subjects, the electromyogram did not show any abdominal muscle activity and the end-expiratory level never departed from the relaxed thoracoabdominal configuration, thus suggesting adequate respiratory muscle relaxation. Aging was associated with significant decreases in Crc and Cab. In the upright posture Crc decreased from 0.164 +/- 0.041 (mean +/- SD) l/cmH2O in the younger subjects (24-39 yr) to 0.114 +/- 0.027 l/cmH2O in the older subjects (55-75 yr). Cab concomitantly fell from 0.032 +/- 0.012 l/cmH2O to 0.020 +/- 0.007 l/cmH2O. These reductions were statistically significant (P less than 0.05-0.01) and were also present in the supine posture. Shifting from the seated to the supine posture did not cause any significant change in Cw but was invariably associated with a decrease in Crc and an increase in Cab.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1989

Mechanical analysis of extrapulmonary volume displacements in the thorax and abdomen.

Currently, the effect of intrathoracoabdominal, extrapulmonary volume displacements (Vep) are not well understood. Various clinical conditions can lead to volume displacements caused by gas or liquid accumulations. To analyze the pressure and volume changes that occur by Vep, we used a mathematical model of chest wall and lung mechanics that accounts for static changes associated with rib cage, diaphragm, abdomen, and lungs. By solving the model equations, we obtained simulations of the pleural and abdominal displacements that clearly differentiate the mechanisms involved. When abdominal displacement occurs, the reduction in lung volume is less than that caused by an equal displacement in pleural space. Abdominal displacement produces an increased pressure that expands the rib cage significantly, whereas pleural displacement does not produce a comparable action. Furthermore, our model predicts the conditions under which the work of inspiration is expected to increase as a consequence of these displacements. Finally, an important distinction is predicted between abdominal displacements caused by gas or liquid accumulation. Although an abdominal gas displacement tends to decrease the resting lung volume, the weight effect of a liquid displacement tends to increase the resting lung volume by pulling down the diaphragm.

Abdomen↗
PubMed1997

Contribution of abdomen and legs to central blood volume expansion in humans during immersion.

The hypothesis was tested that the abdominal area constitutes an important reservoir for central blood volume expansion (CBVE) during water immersion in humans. Six men underwent 1) water immersion for 30 min (WI), 2) water immersion for 30 min with thigh cuff inflation (250 mmHg) during initial 15 min to exclude legs from contributing to CBVE (WI+Occl), and 3) a seated nonimmersed control with 15 min of thigh cuff inflation (Occl). Plasma protein concentration and hematocrit decreased from 68 +/- 1 to 64 +/- 1 g/l and from 46.7 +/- 0.3 to 45.5 +/- 0.4% (P < 0.05), respectively, during WI but were unchanged during WI+Occl. Left atrial diameter increased from 27 +/- 2 to 36 +/- 1 mm (P < 0.05) during WI and increased similarly during WI+Occl from 27 +/- 2 to 35 +/- 1 mm (P < 0.05). Central venous pressure increased from -3.7 +/- 1.0 to 10.4 +/- 0.8 mmHg during WI (P < 0.05) but only increased to 7.0 +/- 0.8 mmHg during WI+Occl (P < 0.05). In conclusion, the dilution of blood induced by WI to the neck is caused by fluid from the legs, whereas the CBVE is caused mainly by blood from the abdomen.

Abdomen↗
PubMed1997

Regulation of muscle stiffness during periodic length changes in the isolated abdomen of the hermit crab.

Reflex activation of the ventral superficial muscles (VSM) in the abdomen of the hermit crab, Pagurus pollicarus, was studied using sinusoidal and stochastic longitudinal vibration of the muscle while recording the length and force of the muscle and the spike times of three exciter motoneurons. In the absence of vibration, the interspike interval histograms of the two larger motoneurons were bimodal; cutting sensory nerves containing most of the mechanoreceptor input removed the short interval peak in the histogram, indicating that the receptors are important in maintaining tonic firing. Vibration of the muscle evoked a reflex increase in motoneuron frequency that habituated after an initial peak but remained above control levels for the duration of stimulation. Motoneuron frequency increased with root mean square (rms) stimulus amplitude. Average stiffness during stimulation was about two times the stiffness of passive muscle. The reflex did not alter muscle dynamics. Estimated transfer functions were calculated from the fast Fourier transform of length and force signals. Coherence was >0.9 for the frequency range of 3-35 Hz. Stiffness magnitude gradually increased over this range in both reflex activated and passive muscle; phase was between 10 and 20 degrees. Reflex stiffness decreased with increasing stimulus amplitudes, but at larger amplitudes, this decrease was much less pronounced; in this range stiffness was regulated by the reflex. The sinusoidal frequency at which reflex bursts were elicited was approximately 6 Hz, consistent with previous measurements using ramp stretch. During reflex excitation, there was an increase in amplitude of the short interval peak in the interspike interval histogram; this was reduced when the majority of afferent pathways was removed. A phase histogram of motoneuron firing during sinusoidal vibration had a peak at approximately 110 ms, also suggesting that an important component of the reflex is via direct projections from the mechanoreceptors. These results are consistent with the hypothesis that a robust feedforward regulation of abdominal stiffness during continuous disturbances is achieved by mechanoreceptors signalling the absolute value of changing forces; habituation of the reflex, its high-threshold for low frequency disturbances and the activation kinetics of the muscle further modify reflex dynamics.

Abdomen↗
PubMed1995

Surgical workshop on liver surgery using isolated perfused livers in moulded casts of the upper abdomen.

The basic training in liver surgery on isolated perfused livers used at the workshop in the First Surgical Course of the Alps--Adriatic Hepatobiliary School is presented. The methods for the excision, preservation, perfusion and preparation of the liver are described, as is the manner of manufacturing the upper abdomen moulded casts, into which an isolated perfused liver is placed for training. The methods proved to be sufficiently successful, enabling participants to perform basic liver surgery like an intraoperative ultrasound investigation, as well as liver dissection techniques, liver suturing, segmental resection and even hepatectomy. Some technical improvements are proposed for future surgical workshops, such as washing out the blood from the liver, and a triple perfusion.

Abdomen↗
PubMed2006

Acute abdomen by varicella zoster virus induced gastritis after autologous peripheral blood stem cell transplantation in a patient with non-Hodgkin's lymphoma.

We report on a 54-year-old male patient with an aggressive T cell non-Hodgkin's lymphoma with abdominal manifestation undergoing autologous peripheral blood stem cell transplantation after high-dose chemotherapy in April 2003. About 4 months after transplantation, he developed severe upper abdominal pain. Ultrasound examination, X-ray, computed tomography of the abdomen and cardiac diagnostics could not explain the symptoms. While empiric therapy with high-dose acyclovir was started, we could document herpetic lesions in the gastric antrum by endoscopy. The epigastric pain rapidly decreased within several days after the start of acyclovir therapy. No herpetic skin lesions were observed at any time during the disease. This report demonstrates the importance of viral-induced gastritis in the differential diagnosis of severe abdominal pain in patients receiving autologous peripheral blood stem cell transplantation.

Abdomen, Acute↗
PubMed1983

Unruptured amoebic liver abscess presenting as acute abdomen.

Unruptured amoebic liver abscess is usually not regarded as a surgical emergency. At University College Hospital, Ibadan, in a two-year period from June 1975 to May 1977, six cases of unruptured amoebic liver abscess underwent emergency exploratory laparotomy because they presented as cases of acute abdomen. The initial diagnoses made by senior physicians included perforated duodenal ulcer, intestinal obstruction, cholecystitis and appendicitis. All patients had persistent draining sinuses after surgery for periods ranging from one to five months. Neither the trophozoites nor the cystic forms of Entamoeba histolytica were present in the "abscess" which was essentially necrotic liver tissue. The diagnosis of amoebic liver abscess was based on clinical features: typical "anchovy" or chocolate-coloured aspirate from the liver, response to anti-amoebic therapy and serological studies.

Abdomen, Acute↗
PubMed1985

Evaluation of the plain abdominal X-ray in the acute abdomen.

The prognostic value of an erect and supine abdominal X-ray was studied prospectively in 97 patients with an acute abdomen. Although 64 (66%) of the radiographs showed an abnormality, the surgical registrar altered his clinical diagnosis on only seven occasions and changed his management on four. A consultant radiologist was the most accurate at reporting the X-rays even without seeing the patient, whilst junior surgical and radiological staff were as accurate as each other. A surgical registrar, however, was more accurate than junior radiologists in making a diagnosis. The investigation was of immediate clinical value in only 4% of the patients, and its use could probably be limited without detriment to patients.

Abdomen, Acute↗
PubMed1986

The abdomen.

This article describes the normal anatomy and physiology of the abdomen. Physical examination techniques illustrate the evaluation of the abdominal structures. The text describes physical presentation of selected diseases and discusses their pathophysiology. The text material is applied through a case study.

Abdomen↗