Measurement of gastric meal and secretion volumes using magnetic resonance imaging.

MRI can assess multiple gastric functions without ionizing radiation. However, time consuming image acquisition and analysis of gastric volume data, plus confounding of gastric emptying measurements by gastric secretions mixed with the test meal have limited its use to research centres. This study presents an MRI acquisition protocol and analysis algorithm suitable for the clinical measurement of gastric volume and secretion volume. Reproducibility of gastric volume measurements was assessed using data from 10 healthy volunteers following a liquid test meal with rapid MRI acquisition within one breath-hold and semi-automated analysis. Dilution of the ingested meal with gastric secretion was estimated using a respiratory-triggered T1 mapping protocol. Accuracy of the secretion volume measurements was assessed using data from 24 healthy volunteers following a mixed (liquid/solid) test meal with MRI meal volumes compared to data acquired using gamma scintigraphy (GS) on the same subjects studied on a separate study day. The mean ± SD coefficient of variance between 3 observers for both total gastric contents (including meal, secretions and air) and just the gastric contents (meal and secretion only) was 3 ± 2% at large gastric volumes (>200 ml). Mean ± SD secretion volumes post meal ingestion were 64 ± 51 ml and 110 ± 40 ml at 15 and 75 min, respectively. Comparison with GS meal volumes, showed that MRI meal only volume (after correction for secretion volume) were similar to GS, with a linear regression gradient ± std err of 1.06 ± 0.10 and intercept -11 ± 24 ml. In conclusion, (i) rapid volume acquisition and respiratory triggered T1 mapping removed the requirement to image during prolonged breath-holds (ii) semi-automatic analysis greatly reduced the time required to derive measurements and (iii) correction for secretion volumes provided accurate assessment of gastric meal volumes and emptying. Together these features provide the scientific basis of a protocol which would be suitable in clinical practice.

Additive effects of gastric volumes and macronutrient composition on the sensation of postprandial fullness in humans.

BACKGROUND/OBJECTIVES: Intake of food or fluid distends the stomach and triggers mechanoreceptors and vagal afferents. Wall stretch and tension produces a feeling of fullness. Duodenal infusion studies assessing gastric sensitivity by barostat have shown that the products of fat digestion have a greater effect on the sensation of fullness and also dyspeptic symptoms than carbohydrates. We tested here the hypothesis that fat and carbohydrate have different effects on gastric sensation under physiological conditions using non-invasive magnetic resonance imaging (MRI) to measure gastric volumes. SUBJECTS/METHODS: Thirteen healthy subjects received a rice pudding test meal with added fat or added carbohydrate on two separate occasions and underwent serial postprandial MRI scans for 4.5 h. Fullness was assessed on a 100-mm visual analogue scale. RESULTS: Gastric half emptying time was significantly slower for the high-carbohydrate meal than for the high-fat meal, P=0.0327. Fullness significantly correlated with gastric volumes for both meals; however, the change from baseline in fullness scores was higher for the high-fat meal for any given change in stomach volume (P=0.0147), despite the lower energy content and faster gastric emptying of the high-fat meal. CONCLUSIONS: Total gastric volume correlates positively and linearly with postprandial fullness and ingestion of a high-fat meal increases this sensation compared with high-carbohydrate meal. These findings can be of clinical interest in patients presenting with postprandial dyspepsia whereby manipulating gastric sensitivity by dietary intervention may help to control digestive sensations.

Novel MRI tests of orocecal transit time and whole gut transit time: studies in normal subjects.

BACKGROUND: Colonic transit tests are used to manage patients with Functional Gastrointestinal Disorders. Some tests used expose patients to ionizing radiation. The aim of this study was to compare novel magnetic resonance imaging (MRI) tests for measuring orocecal transit time (OCTT) and whole gut transit time (WGT), which also provide data on colonic volumes. METHODS: 21 healthy volunteers participated. Study 1: OCTT was determined from the arrival of the head of a meal into the cecum using MRI and the Lactose Ureide breath test (LUBT), performed concurrently. Study 2: WGT was assessed using novel MRI marker capsules and radio-opaque markers (ROMs), taken on the same morning. Studies were repeated 1 week later. KEY RESULTS: OCTT measured using MRI and LUBT was 225 min (IQR 180-270) and 225 min (IQR 165-278), respectively, correlation r(s) = 0.28 (ns). WGT measured using MRI marker capsules and ROMs was 28 h (IQR 4-50) and 31 h ± 3 (SEM), respectively, correlation r(s) = 0.85 (p < 0.0001). Repeatability assessed using the intraclass correlation coefficient (ICC) was 0.45 (p = 0.017) and 0.35 (p = 0.058) for MRI and LUBT OCTT tests. Better repeatability was observed for the WGT tests, ICC being 0.61 for the MRI marker capsules (p = 0.001) and 0.69 for the ROM method (p < 0.001) respectively. CONCLUSIONS & INFERENCES: The MRI WGT method is simple, convenient, does not use X-ray and compares well with the widely used ROM method. Both OCTT measurements showed modest reproducibility and the MRI method showed modest inter-observer agreement.

Effects of various food ingredients on gall bladder emptying.

BACKGROUND/OBJECTIVES: The emptying of the gall bladder in response to feeding is pivotal for the digestion of fat, but the role of various food ingredients in contracting the gall bladder postprandially is not well understood. We hypothesized that different food ingredients, when consumed, will have a different effect on stimulating gall bladder emptying. To investigate this we designed two randomized, investigator-blind, cross-over studies in healthy subjects using magnetic resonance imaging (MRI) to measure gall bladder volumes serially and non-invasively. SUBJECTS/METHODS: Study 1: exploratory study evaluating the effects of 10 different food ingredients on gall bladder emptying in eight healthy subjects. The choice of ingredients varied from common items like coffee, tea and milk to actives like curcumin and potato protease inhibitor. Study 2: mechanistic study investigating the cholecystokinin (CCK) dose response to the best performer ingredient from Study 1 in 21 healthy subjects four ways. RESULTS: The largest gall bladder volume change in Study 1 was observed with fat, which therefore became the dose-response ingredient in Study 2, where the maximum % gall bladder volume change correlated well with CCK. CONCLUSIONS: These serial test-retest studies showed that the fasted gall bladder volume varied remarkably between individuals and that individual day-to-day variability had wide coefficients of variation. Improved knowledge of how to stimulate bile release using food ingredients will be useful to improve in vitro-in vivo correlation of bioavailability testing of hydrophobic drugs. It could improve performance of cholesterol-lowering plant stanol and sterol products and possibly aid understanding of some cholesterol gallstone disease.

The effects of loperamide, or loperamide plus simethicone, on the distribution of gut water as assessed by MRI in a mannitol model of secretory diarrhoea.

BACKGROUND: Loperamide (LOP) is an anti-diarrhoeal agent which is thought to act largely by slowing transit with an uncertain effect on the fluid content of the small and large bowel in humans. Adding simethicone (SIM) to LOP improves its efficacy, but the mechanism of interaction is unclear. Novel MRI techniques to assess small bowel water content (SBWC) have shown that mannitol solutions markedly increase SBWC and can be used as a model of diarrhoea. AIM: We aimed to use quantitative MRI techniques to compare the actions in the gut of LOP and LOP + SIM in a model of secretory diarrhoea using mannitol. METHODS: A total of 18 healthy volunteers ingested capsules containing placebo (PLA) or 12 mg LOP or 12 mg LOP + 125 mg SIM. After 100 min they were given a drink containing 5% mannitol in 350 mL of water. They underwent baseline fasting and postprandial serial MRI scans at 45 min intervals for 4.5 h after ingesting the drink. A range of MRI sequences was acquired to image the gut. RESULTS: LOP and LOP + SIM significantly accelerated gastric emptying (P < 0.03) and reduced SBWC during the late phase (135-270 min after mannitol ingestion), P < 0.009, while delaying arrival of fluid in the ascending colon (AC). The relaxation time T2 of the contents of the AC was reduced by both drugs (P < 0.0001). CONCLUSIONS: LOP and LOP + SIM accelerate gastric emptying, but reduce small bowel water content which may contribute to the delay in oral-caecal transit and overall anti-diarrhoeal effect.

Non-invasive quantification of small bowel water content by MRI: a validation study.

Substantial water fluxes across the small intestine occur during digestion of food, but so far measuring these has required invasive intubation techniques. This paper describes a non-invasive magnetic resonance imaging (MRI) technique for measuring small bowel water content which has been validated using naso-duodenal infusion. Eighteen healthy volunteers were intubated, with the tube position being verified by MRI. After a baseline MRI scan, each volunteer had eight 40 ml boluses of a non-absorbable mannitol and saline solution infused into their proximal small bowel with an MRI scan being acquired after each bolus. The MRI sequence used was an adapted magnetic resonance cholangiopancreatography sequence. The image data were thresholded to allow for intra- and inter-subject signal variations. The MRI measured volumes were then compared to the known infused volumes. This MRI technique gave excellent images of the small bowel, which closely resemble those obtained using conventional radiology with barium contrast. The mean difference between the measured MRI volumes and infused volumes was 2% with a standard deviation of 10%. The maximum 95% limits of agreement between observers were -15% to +17% while measurements by the same operator on separate occasions differed by only 4%. This new technique can now be applied to study alterations in small bowel fluid absorption and secretion due to gastrointestinal disease or drug intervention.

Coral larvae conservation: physiology and reproduction.

Coral species throughout the world's oceans are facing severe environmental pressures. We are interested in conserving coral larvae by means of cryopreservation, but little is known about their cellular physiology or cryobiology. These experiments examined cryoprotectant toxicity, dry weight, water and cryoprotectant permeability using cold and radiolabeled glycerol, spontaneous ice nucleation temperatures, chilling sensitivity, and settlement of coral larvae. Our two test species of coral larvae, Pocillopora damicornis (lace coral), and Fungia scutaria (mushroom coral) demonstrated a wide tolerance to cryoprotectants. Computer-aided morphometry determined that F. scutaria larvae were smaller than P. damicornis larvae. The average dry weight for P. damicornis was 24.5%, while that for F. scutaria was 17%, yielding osmotically inactive volumes (V(b)) of 0.22 and 0.15, respectively. The larvae from both species demonstrated radiolabeled glycerol uptake over time, suggesting they were permeable to the glycerol. Parameter fitting of the F. scutaria larvae data yielded a water permeability 2 microm/min/atm and a cryoprotectant permeability = 2.3 x 10(-4) cm/min while modeling indicated that glycerol reached 90% of final concentration in the larvae within 25 min. The spontaneous ice nucleation temperature for F. scutaria larvae in filtered seawater was -37.8+/-1.4 degrees C. However, when F. scutaria larvae were chilled from room temperature to -11 degrees C at various rates, they exhibited 100% mortality. When instantly cooled from room temperature to test temperatures, they showed damage below 10 degrees C. These data suggest that they are sensitive to both the rate of chilling and the absolute temperature, and indicate that vitrification may be the only means to successfully cryopreserve these organisms. Without prior cryopreservation, both species of coral settled under laboratory conditions.

Blunt bladder trauma: manifestation of severe injury.

Twenty-nine patients with bladder injuries requiring operative treatment as a result of blunt trauma are presented. Motor vehicle accidents accounted for 86 per cent of the injuries. Hypotension and gross hematuria were the most prevalent clinical features, 68 per cent and 97 per cent, respectively. All patients had multiple associated injuries requiring operative treatment, average 2.9 per patient. Pelvic fractures occurred in 93 per cent and intra-abdominal injuries in 48 per cent of patients. The majority of ruptures (72%) were intraperitoneal. Mortality, related to associated injuries, was high (34%), attesting to the magnitude of injury sustained by the victim.

Blunt trauma to the liver. Analysis of management and mortality in 323 consecutive patients.

This study represents a 6 year 4 month experience with blunt trauma to the liver of patients from the Maryland Institute for Emergency Medical Services Systems, a major regional trauma center. The significance of this study is that it describes a large, relatively homogeneous population and analyzes what the state of the art for liver trauma has been in a center dedicated solely to trauma that has a full-time staff of trained traumatologists. Three hundred twenty-three consecutive patients with blunt liver trauma are presented, representing 3.5% of 9271 patients admitted to the institute over the period of this study. Ninety per cent had associated traumatic injuries requiring operative intervention. A mortality rate of 31% (101 patients) was noted; 41.5% of the deaths, due primarily to liver injury, occurred intraoperatively during the initial operation following admission. The use of simple suture techniques and resectional debridement to control hemorrhage are advocated. Anatomic lobectomy, intracaval shunting, and hepatic artery ligation were uniformly unsuccessful. The use of drains was associated with a significantly increased incidence of infectious complications (p less than 0.00002).

Blunt injury to the diaphragm: an analysis of 44 patients.

Forty-four patients sustaining blunt trauma with resultant diaphragmatic rupture during a 5 1/2-year period are presented. In 41 (93%), the diagnosis was established within 6 hours of admission. The correct diagnosis was made preoperatively in 19 patients operated on acutely (42%), in 22 (53%), ruptured diaphragm was an incidental finding at celiotomy or thoracotomy. The admission chest roentgenography, diagnostic peritoneal lavage, UGI contrast studies, and computed tomography were the most useful diagnostic aids. The transabdominal operative approach was utilized in 39 patients (89%). All patients had associated extra-abdominal injuries and 26 patients (59%) had associated intra-abdominal injuries. The mortality rate was 20.4%; early deaths were attributable to hemorrhage and severe head injury, late deaths to sepsis and progressive multiorgan failure.

Splenic conservation after multiple trauma in adults.

The traditional management of splenic injuries is undergoing serious challenge. During the four year period from 1980 to 1983, 60 of 230 patients with injured spleens operated upon at the Maryland Institute for Emergency Medical Services' Shock Trauma Center have had splenic salvage. Motor vehicle accidents accounted for 57 of the 60 injuries (95 per cent). Fifty-eight patients (97 per cent) had major associated extra-abdominal injuries (average 1.9 injuries per patient) requiring additional operative procedures. Concurrent intra-abdominal injury was present in 37 patients (62 per cent). The mean operating time was 106 minutes; 98 minutes for those patients with isolated splenic injuries and 115 minutes for those with associated minor intra-abdominal injuries. The average amount of blood transfused during celiotomy was 3.5 units of packed red blood cells per patient. As familiarity and confidence with the techniques have accrued, the number of splenic preservation procedures has steadily increased from approximately 10 per cent to more than 50 per cent. Complications related to splenorrhaphy per se were few. The mortality was 10 per cent; all deaths were secondary to associated injuries. Criteria for and contraindications to splenic salvage in patients with multiple trauma are presented and discussed.

Non-left sided diaphragmatic rupture due to blunt trauma.

An analysis of the clinical, diagnostic and therapeutic features of non-left sided diaphragmatic rupture due to blunt trauma to the torso was performed in ten patients. All patients had multiple systems involved. False-positive peritoneal lavage occurred in three patients (37.5 per cent). The correct diagnosis was made only once preoperatively; diaphragmatic rupture usually being an incidental finding at celiotomy or thoracotomy. Mortality is high and is a manifestation of associated injuries.

Acute posttraumatic acalculous cholecystitis.

A series of 18 patients who had acute posttraumatic acalculous cholecystitis over a 12 year period was presented. An attempt was made to determine the etiologic factors involved in the pathogenesis of the disease. Large amounts of parenteral narcotics administered over a prolonged period were evident in all patients. Narcotic-induced biliary stasis appeared to be the prime factor involved in the genesis of acalculous cholecystitis after trauma. Other factors such as the presence of shock, respiratory failure, acute renal failure, parenteral hyperalimentation, and multiple transfusions were less prevalent and were not temporally related to the onset of the disease.

Blunt intestinal trauma. A modern-day review.

During the 5-year period from January 1978 through December 1982, 196 patients with blunt trauma to the small bowel, colon, or mesentery were treated at the Maryland Institute for Emergency Medical Services Systems (MIEMSS) Shock Trauma Center. More than 80% of these patients were the victims of motor vehicle accidents and therefore commonly had multisystem injuries. Sixty of these patients suffered 83 major injuries in the form of perforation or mesenteric injury resulting in ischemic bowel. This group accounted for 6.9% of the 870 patients who had celiotomy for blunt trauma during this period. Several significant observations were made. All injuries, except one, were diagnosed by peritoneal lavage. Only two duodenal injuries were present. Perforations involving the jejunum and ileum were distributed throughout the entire length of the small bowel. Colon injuries comprised one-fourth of the major injuries, with most occurring in the ascending and sigmoid colon. There were 16 deaths, 6 of which occurred as a result of complications from the bowel injury.

Blunt abdominal trauma. A 5-year analysis of 870 patients requiring celiotomy.

This study represents the experience with blunt trauma to the abdomen of patients from a major regional trauma center. Eight hundred and seventy patients with blunt abdominal trauma are reviewed, representing 12.89% of the total admissions over a 5-year period. The motor vehicle continues to be the major cause (89.5%) of injury to these patients. Thirty per cent had positive blood alcohol. Intra-abdominal injuries in this group necessitating operative intervention were based on the use of peritoneal lavage. Negative celiotomies occurred in 10.2% of these patients. Of the injuries incurred, the spleen was involved 42%, the liver 35.6%, the serosa, diaphragm, bowel, and blood vessels were involved to a lesser extent. Only 0.4% of the patients suffered direct injury to the stomach, duodenum, and pancreas, data which should preclude routine exploration of retroperitoneal structures unless by obvious retroperitoneal injury is noted. Additional surgical intervention for associated injuries was seen in 50.54% of this patient group.

Traumatic hemipelvectomy: report of two survivors and review.

Two surviving patients with traumatic hemipelvectomy are presented. Rapid transport, aggressive initial resuscitation, and attention to detail in the rehabilitation phase are necessary for the successful management of these patients. The viability of the psoas muscle should be assessed, because of the high possibility of avulsion. Associated nerve injury and complicating meningitis can be serious problems in the management of such patients. There is need to include this entity in the existing classifications of pelvic fractures. Hemipelvectomy is proposed as an alternative in the management of the severe unilateral open pelvic fracture with uncontrollable bleeding.

Cholangiocarcinoma. A place for brachytherapy.

Carcinoma arising from the common hepatic duct is unique in its clinical course and is difficult to manage due to its dismal prognosis. The case reported and the treatment reflected not only the highly selective process but also the innovation of the intracatheter brachytherapy technique available to date. Exploratory laparotomy appears essential to identify the extent of the tumor and localize the area for brachytherapy. Percutaneous transhepatic cholangiography and placements of the indwelling catheter should be reserved for non-surgical candidates whose long-term survival is limited. Review of pertinent literature also shows various roles of irradiation in the management of this disease. The potentials of intraoperative therapy, brachytherapy, external beam therapy and their combinations were examined to implement the future recommendation of the treatment.

MAS trousers improperly applied causing a compartment syndrome in lower-extremity trauma.

A case is presented in which the leg segments of MAS trousers were deflated without deflating the abdominal segment, causing the trousers to act as a venous tourniquet. As a result bleeding and edema secondary to a pertrochanteric hip fracture were aggravated, causing a compartment syndrome in the thigh; fasciotomy became necessary. MAS trousers must be inflated in proper sequence, the leg segments first and then the abdominal portion. In deflation, the order is reversed. Only if this sequence is followed can MAS trousers be used safely.