Effect of nasal continuous positive airway pressure on esophageal function

OBJECTIVE

The purpose of this study was to conduct a prospective investigation of the mechanism(s) of nasal continuous positive airway pressure (CPAP) upon the reduction of recumbent gastroesophageal reflux.

DESIGN

Prospective assessment.

SETTING

Health Sciences Center and St. Boniface General Hospital, Winnipeg, Manitoba.

METHODS

An esophageal motility examination was conducted on 16 patients during the application of nasal CPAP set at 0 cm, 4 cm, and 8 cm water pressure. Esophageal parameters studied were wave amplitude and velocity, midesophageal resting pressure, and upper and lower esophageal sphincter resting pressure.

RESULTS

The midesophageal resting pressure increased significantly from a baseline of -3.5 +/- 1.4 mm Hg to -1.6 +/- 1.8 mm Hg at 4 cm CPAP (p < .01) and -0.9 +/- 1.2 mm Hg at 8 cm CPAP (p < .01).

CONCLUSIONS

The known reduction of nocturnal reflux that occurs when patients use an application of nasal CPAP appears to be related to direct mechanical compression of the esophagus. Results of an earlier report suggesting a reflex response by the lower sphincter were not reproduced.

Impact of ingested liquids on 24-hour ambulatory pH tests

A prospective investigation of the impact of ingested liquids on 24-hr pH test scores was conducted. Eighty-two patients contributed 142 samples. The liquids used were coffee/tea (N = 35), water (N = 32), fruit juice (N = 29), cola (N = 34), and beer (N = 12). The pH of cola, juice, and beer are approximately 3.0. The parameters studied included: total test time, total drink time, total minutes of pH < 4.0 during drink, minutes of < pH 4.0 10 min before drink, and minutes of pH < 4.0 10 min following drink. Analysis was performed using one-way ANOVA and repeated measures. Age of patients, total test time, and total time pH < 4.0 were not significantly different (P > 0.05). The total time to consume the drink was significantly greater (P < 0.05) for beer than all other liquids. The total time (7.7 +/- 6.0 min) pH < 4.0 for cola was significantly different (P < 0.023) than beer (3.3 +/- 3.7 min), tea/coffee (1.4 +/- 6.5 min), and water (1.1 +/- 2.5 min). The percentage of total time pH < 4.0 was not significantly different (P > 0.05) among any of the liquids. The percentage of time pH < 4.0 during the drink was the highest for cola (63 +/- 47%) and juice (51 +/- 57%); water, coffee/tea, and beer were not significantly different (P > 0.05). Although the impact of cola and juice were the greatest, none of these had an impact that exceeded 0.5%. The lack of impact of beer appears to be due to the increased period of time it takes to consume. We conclude that the impact of ingested fluids is minimal and can probably be disregarded in most patient groups.

A prospective assessment of gastroesophageal reflux before and after treatment of achalasia patients: pneumatic dilation versus transthoracic limited myotomy

OBJECTIVES

We conducted this study to determine whether reflux should be a major consideration in the choice of treatment for achalasia patients. Achalasia patients undergoing either pneumatic dilation or transthoracic limited esophagomyotomy were monitored for reflux before and after treatment, for comparison.

METHODS

Twenty-four hour ambulatory esophageal pH tests and esophageal manometry were performed on 32 consecutive, untreated achalasia patients. Studied (before and after treatment) were 17 patients who underwent pneumatic dilation and 15 patients who received transthoracic limited myotomy without fundoplication. All follow-up studies were completed within 12 months of treatment.

RESULTS

The ages of the two groups were not significantly different (p > 0.05, 45 +/- 9 yr myotomy vs. 44 +/- 13 yr dilation). The resting lower esophageal sphincter pressure was not significantly different (p > 0.05 before treatment) between groups but was reduced significantly (p < 0.05 after treatment) in both groups (30 +/- 9 mm Hg before vs. 9 +/- 4 mm Hg after myotomy, and 27 +/- 10 mm Hg before vs. 11 +/- 4 mm Hg after pneumatic dilation. The total time the pH was < 4.0 was not significantly different, p > 0.05, in either group before treatment (myotomy, 3.7 +/- 4.4%; dilation, 2.9 +/- 4.9%) or after treatment (myotomy, 8.6 +/- 9.2%; dilation, 10.2 +/- 15.9%). Twelve of 32 patients (38%), had a percent total time < 4.0 that exceeded 6% after treatment, eight of whom were asymptomatic.

CONCLUSIONS

These results indicate that the amount of reflux after treatment by both pneumatic dilation and transthoracic esophagomyotomy is similar. The absence of reflux symptoms in treated achalasia patients does not exclude the possibility of significant acid reflux.

Ambulatory esophageal pH testing. Referral patterns, indication, and treatment in a Canadian teaching hospital

Over a 30-month period, 867 esophageal pH studies were conducted in a Canadian teaching hospital; of these, 315 tests were recorded in patients who were first-time referrals having no chest or upper gastrointestinal surgery and taking no medication that would affect the results. Patients were referred by gastroenterologists, general surgeons, ENT surgeons, thoracic surgeons, and a miscellaneous group. Patients were classified based on: pH results [abnormal = % total time pH < 4.0 (ie, > 6.0%)], manometry (abnormal = LES resting pressure < 5 mm Hg and/or abnormal peristalsis), and gender. Fifty-one percent (162/315) of the patient records demonstrated abnormal reflux. Intergroup comparisons of severity of reflux using two-way analysis of variance demonstrated no significant differences (P = 0.13). In the 162 patients who refluxed, 70% (N = 108) had normal motility studies; however, when the severity of reflux was compared, patients with abnormal motility (N = 54) demonstrated significantly more severe reflux (19.8 +/- 12.8 vs 16.2 +/- 11.3) P = 0.02. In those patients with abnormal manometry, no significant differences (P = 0.44) in the severity of reflux were found among those with abnormal peristalsis (N = 27), low resting pressure (N = 17), or a combination of aperistalsis and low LES pressure (N = 10). Symptomatic patients with reflux (N = 107) demonstrated a significantly greater percent time pH < 4.0 than those with asymptomatic reflux (N = 55); 18.1 +/- 11.5% vs 16.2 +/- 12.7%, P = 0.04. When the severity of reflux by gender was compared, no significant differences were found [18.3 +/- 11.9 (male) N = 91 vs 16.2 +/- 11.9 (female) N = 71, P = 0.11]. The results from this study show that: (1) esophageal pH testing is important in subspecialties other than gastroenterology and that the clinical yield is high in all referring groups, (2) esophageal pH testing and manometry are complimentary tests, but that reflux occurs commonly in association with normal manometry, (3) asymptomatic reflux was found in 34% of the patients with abnormal reflux scores, and (4) the severity of reflux in male and female patients is similar.

Renal abscesses: appearance on gadolinium-enhanced magnetic resonance images

PURPOSE

To determine the appearance of renal abscesses on gadolinium-enhanced magnetic resonance (MR) images, we reviewed 12 MR studies of eight patients with renal abscesses. These findings were compared with findings on other imaging modalities.

METHODS

Eight patients underwent 12 MR studies at 1.5 T, including T1-weighted gradient echo and fat-suppressed spin echo pre- and post-Gd-DTPA enhancement. Two radiologists retrospectively reviewed the MR images and compared MR findings to the findings on contrast-enhanced computed tomography (CECT) in five patients, noncontrast computed tomography (NCCT) in two patients, and ultrasound in all patients.

RESULTS

On contrast-enhanced MR images, renal abscesses were clearly depicted as heterogeneously low-signal-intensity lesions. Four patients had solitary abscesses, and four had multiple abscesses. Prominent perinephric inflammatory stranding was observed in six patients and was best shown on gadolinium-enhanced T1 fat-suppressed images. CECT findings were comparable to contrast-enhanced MR images, although contrast resolution was less on CECT images in all cases. Renal abscesses were poorly shown on NCCT and ultrasound images.

CONCLUSION

Renal abscesses are clearly shown on gadolinium-enhanced MR images as low-signal-intensity lesions associated with prominent perinephric inflammatory strands. In this study, NCCT and ultrasound studies are poor at defining abscesses. Despite lesser contrast resolution of CECT versus MRI, the findings in cases of renal abscesses are similar. In patients with elevated serum creatinine, iodine contrast allergy, or the need for serial exams, MRI may be the best imaging technique to evaluate renal abscesses.

Effect of severe gastroesophageal reflux on sleep stage in patients with aperistaltic esophagus

Polysomnography and esophageal pH studies were conducted in 13 patients with an aperistaltic esophagus; seven of these had scleroderma and six were patients treated for achalasia. The percentage total time of pH<4.0 when recumbent exceeded 30% for both groups. There was a total of 51 reflux events for both groups. There were 22 reflux events recorded for both groups that were less than 5 min in length and 29 events greater than 5 min. In 26 of 32 (81%) instances, patients either began awake and went to sleep during a reflux event or did not awake during a reflux event. Only six of 32 (19%) reflux events caused sleep disruption. We conclude that even the severe reflux demonstrated in this subset of patients does not always disrupt sleep. Patients may have severe prolonged reflux and not arouse.

Reproducibility of ambulatory esophageal pH monitoring in the aperistaltic esophagus

The reproducibility of ambulatory 24-h esophageal pH monitoring was evaluated in 16 consecutive patients by comparing the difference in two consecutive 24-h periods. The study group included 8 patients with scleroderma esophagus and 8 treated achalasia patients. The amount of reflux was expressed as the percentage of time the pH was < 4.0. Both groups demonstrated excellent intrapatient reproducibility overall: 96% in scleroderma patients and 95% in those patients with achalasia. The least concordance was found in the lengths of the longest reflux events-70% when supine in scleroderma patients and 59% when upright in patients with achalasia. There was no significant difference (p > 0.05) between day 1 and day 2 for either group of patients for any of the elements studied. These results indicate that intrapatient variability of gastroesophageal reflux in patients with scleroderma esophagus and treated patients with achalasia is very low and following therapeutic intervention, a high level of confidence can be placed in subsequent pH monitoring as an indicator of treatment effect.

Multilocular cystic nephroma: MR imaging appearance with current techniques, including gadolinium enhancement

The purpose of the study was to define the MRI appearance of multilocular cystic nephroma (MLCN), using current MR techniques, including gadolinium (Gd)-enhanced sequences. Seven patients with MLCN underwent MR imaging with the following sequences: T1-weighted spin echo with fat suppression (T1FS, five patients), T1-weighted spoiled gradient echo (SGE, seven patients), T2-weighted fast spin echo (two patients), and Gd-enhanced T1FS (seven patients) and SGE (seven patients). MLCN was histologically proven by resection of the mass in six patients and by observation of typical imaging features with stability in appearance over a 6-month period in one patient. Lesion morphology and signal intensity (SI) features were retrospectively evaluated. MRI features of MLCN included a solitary cystic lesion with thin internal septations in six patients and a cluster of closely grouped cysts similar in size in one patient. Individual cystic spaces demonstrated SI, varying from low to high on T1-weighted images in three patients and demonstrated low-to-intermediate SI in four patients. Herniation of the lesions into the renal collecting system and thin enhancing septa were demonstrated in all patients. A complex cystic renal lesion with enhancing septa and herniation into the renal collecting system are the characteristic MR findings of MLCN. The direct multiplanar capability of MR may optimally show the relationship of MLCN to the renal pelvis and, thus, facilitate correct diagnosis.

MR imaging of the gastrointestinal tract

The use of T1-weighted sequences with reduced artifacts such as breath-hold gradient echo and fat-suppressed spin echo imaging has rendered MR imaging an effective technique for the evaluation of bowel disease. Various malignancies are depicted on MR images with diagnostic information comparable to CT images; concurrent evaluation for liver metastases are better performed by MR imaging. The high sensitivity for uptake of intravenous gadolinium suggests that MR imaging may play an important role in the evaluation of inflammatory bowel disease.

Reflux in untreated achalasia patients

We made a prospective assessment of acid exposure in the distal esophagus in 48 consecutive untreated patients with achalasia using 24-h ambulatory esophageal pH studies. The majority of patients (38/48) experienced reflux that was within reported values for normal controls (total time pH < 4.0, 1.8 +/- 1.9%). Approximately 20% (10/48), however, demonstrated abnormal acid exposure (total time pH < 4.0, 18.8 +/- 14.8%). The difference in reflux expressed by these two groups was not due to a significant difference in lower esophageal sphincter pressure (p > 0.05) or retained food. An in vitro model of lactobacillus fermentation supported the contention that true acid reflux accounted for changes in esophageal pH. Repeat pH studies were obtained in 23 patients following treatment: 15 underwent pneumatic dilatation and 8 underwent limited myotomy. Although no significant differences were found between pre- and posttreatment reflux, some patients undergoing either treatment were found to demonstrate increased acid exposure. In conclusion, we believe that patients with achalasia should be tested by pH study both before and after treatment. Most of the patients who demonstrated significant pretreatment reflux were asymptomatic, and both methods that were used to decrease resting sphincter pressure were shown to be able to increase distal acid exposure.

The effect of nasal CPAP on nocturnal reflux in patients with aperistaltic esophagus

It has been shown that nasal continuous positive airway pressure (nasal CPAP) significantly reduces nocturnal reflux both in patients with sleep apnea and in patients without sleep apnea but consistent abnormal nocturnal reflux. The mechanism by which CPAP is thought to reduce reflux includes the elevation of the resting lower esophageal sphincter (LES) pressure. In this study, we tested the effect of nasal CPAP in two groups of patients with aperistaltic esophagus but with different resting LES pressure. Seven patients with scleroderma esophagus and six patients treated for achalasia were tested over a 48-h period. On the first night, the patients were untreated; on the second night, both groups received applied nasal CPAP at 8 cm H2O pressure. The percentage of time the pH < 4.0, the number of reflux events > 5 min, and the length of the longest reflux event were all significantly reduced in the patients with achalasia (p < 0.03), but not in the scleroderma group (p > 0.20). These results suggest that a residual resting LES pressure greater than that demonstrated by patients with scleroderma (> 10 mm Hg) may be necessary for nasal CPAP to affect nocturnal reflux.

Reflux after esophagectomy and interposition of right colon

OBJECTIVE

To determine the nature of reflux after esophagectomy and interposition of right colon.

DESIGN

A case series.

SETTING

A university hospital.

PATIENTS

Five patients (mean age 43 years) in whom right colon had been interposed after total esophagectomy.

INTERVENTIONS

Endoscopy and biopsy, manometry, 24-hour ambulatory pH testing.

MAIN OUTCOME MEASURES

Endoscopic and histologic appearances of the colon, type of motor activity in the grafted colon and the type of reflux.

RESULTS

In all patients the grafted colon was macroscopically and microscopically normal. There was nonperistaltic motor activity in the interposed colon in two patients. All patients had an abnormal pattern of alkaline reflux, and one patient had abnormal acid reflux.

CONCLUSIONS

The clinical effect of alkaline reflux in patients with colonic interposition after total esophagectomy may be slight. Histologic and gross changes are likely to be minimal.

Hepatic hemangiomas: a multi-institutional study of appearance on T2-weighted and serial gadolinium-enhanced gradient-echo MR images

PURPOSE

To define the appearance of hepatic hemangiomas on T2-weighted and serial gadolinium-enhanced gradient-echo magnetic resonance (MR) images.

MATERIALS AND METHODS

In four university hospitals, with 1.0- or 1.5-T MR imaging, T2-weighted and T1-weighted gradient-echo images were obtained in 66 adult patients before and at 1, 45, and 90 seconds and 10 minutes after injection of a gadolinium chelate. Hemangiomas were categorized as small (< 1.5-cm-diameter), medium (1.5-5.0-cm), and large (> 5.0-cm) tumors.

RESULTS

In all, 154 hemangiomas were depicted (81 small, 56 medium, and 17 large tumors). All 154 lesions were hyperintense on T2-weighted images. Three patterns of contrast enhancement were observed: (a) uniform enhancement at 1 second (35 of 81 small lesions and no medium or large lesions), (b) peripheral nodular enhancement progressing centripetally to uniform enhancement (75 of all 154 lesions), and (c) peripheral nodular enhancement with persistent hypointensity centrally (44 of all 154 lesions, including 16 of 17 large lesions).

CONCLUSION

Three patterns of enhancement of hemangiomas were observed. High signal intensity on T2-weighted images provided complementary information.

Comparison of magnetic resonance imaging and endoscopy in distinguishing the type and severity of inflammatory bowel disease

Twenty consecutive patients with first-time presentation of suspected inflammatory bowel disease underwent both endoscopy with biopsy and magnetic resonance imaging (MRI) within a 3-day period; the relative abilities of endoscopy and MRI to distinguish ulcerative colitis (UC) from Crohn's disease (CD) and to determine the severity of the disease process were compared. In 18 of 20 patients, a diagnosis of UC or CD could be made on histological specimens. MRI correctly diagnosed 17 of these 18 patients using T1-weighted fat-suppressed spin echo and gadolinium enhancement. Endoscopy correctly diagnosed 15 patients. Overall, MRI was not significantly better (p > 0.05) than endoscopy in distinguishing UC from CD. MRI correctly graded the severity of inflammatory changes in 13 of 20 patients, and endoscopy did so in 11 of 20. MRI and endoscopy findings were within one grade of histology findings in seven patients each. No significant difference (p > 0.05) was found between MRI and endoscopy in the ability to estimate the severity of the disease (as determined from biopsies). Bowel wall thickness measured on MR images demonstrated good correlation with percentage of contrast enhancement: r = 0.61; p = 0.003. In sum, magnetic resonance imaging was shown to be comparable with endoscopy in differentiating UC from CD and in gauging the severity of disease. Transmural assessment, sagittal imaging, and the lack of invasiveness were attractive features of MRI.

Solitary hepatic metastasis: comparison of dynamic contrast-enhanced CT and MR imaging with fat-suppressed T2-weighted, breath-hold T1-weighted FLASH, and dynamic gadolinium-enhanced FLASH sequences

Twenty consecutive cancer patients with a solitary hepatic metastasis detected with dynamic contrast-material-enhanced computed tomography (CT) who were considered for hepatic resection underwent magnetic resonance (MR) imaging within 18 days after CT. Histologic confirmation was obtained in all lesions. CT depicted 20 solitary lesions. MR imaging showed a solitary lesion in 14 patients, two lesions in three patients, and more than two lesions in three patients, for a total of 37 lesions. Twenty-three lesions less than 2 cm in diameter were missed with CT, and six lesions less than 1.3 cm in diameter were missed with MR imaging. MR imaging was superior to CT in the detection of hepatic metastases on a patient-by-patient basis (P < .01). The results suggest that MR imaging is superior to dynamic contrast-enhanced CT for the detection of hepatic metastases.

Ciliated hepatic foregut cysts: US, CT, and contrast-enhanced MR imaging

Hepatic foregut cysts are uncommon lesions of the liver. In this report we prospectively examined two patients by means of computed tomography (CT), ultrasound, and contrast-enhanced magnetic resonance imaging. Ciliated hepatic foregut cysts were subsequently demonstrated in both patients following CT-guided biopsy. Magnetic resonance imaging was found to be useful in differentiating these cysts from other lesions.

Nasal continuous positive airway pressure. A new treatment for nocturnal gastroesophageal reflux?

Nasal continuous positive airway pressure (CPAP) reduces nocturnal gastroesophageal reflux (GER) in obstructive sleep apnea syndrome (OSAS) patients. The primary objectives of our investigation were to determine if CPAP could reduce reflux in non-OSAS patients and, if so, by what mechanism. Esophageal pH was monitored for 48 h in six nocturnal reflux patients. During the first 24 h, basal reflux data were collected; the second night, nasal CPAP was administered (pressure = 8 cm H2O). Esophageal manometry was obtained in six healthy adult volunteers both on and off nasal CPAP (pressure = 8 cm H2O) to ascertain CPAP's effects on esophageal pressure and peristalsis. The six reflux patients experienced less nocturnal GER while on CPAP. The mean percent time esophageal pH < 4 was reduced from 27.7 +/- 10.0 to 5.8 +/- 2.6 (p < 0.004); the mean reflux duration dropped from 2.1 +/- 0.6 to 0.9 +/- 0.5 min (p < 0.03); and the mean duration of longest reflux improved from 84.3 +/- 32.6 to 13.8 +/- 6.9 min (p < 0.01). The CPAP raised the mean resting midesophageal pressure by 4.4 cm H2O (p < 0.01) and the mean resting lower esophageal pressure (LES) by 13.2 cm H2O (p < 0.02) in the healthy volunteers. Nasal CPAP effectively reduced nocturnal GER in six patients with nocturnal reflux. The antireflux activity of CPAP is likely due to passive elevation of intraesophageal pressure and possibly to reflex LES constriction.

Magnetic resonance imaging evaluation of the local extent of colorectal mass lesions

Magnetic resonance imaging (MRI) was conducted in 21 patients with known or suspected colorectal mass lesions. Imaging was carried out at 1.5 T using Fast Low Angle Shot (FLASH) and fat-suppressed (T1FS) gadolinium enhanced sequences. The lesions studied included adenocarcinoma (n = 16), lipoma (n = 2), villous adenoma with foci of adenocarcinoma (n = 1), malignant melanoma (n = 1), and rectal lymphoma (n = 1). Correlation was made with surgical findings in 14 patients, 10 of whom had tumors resected. Bowel wall involvement, tumor size, and extension demonstrated on MR images was correlated with histopathology findings. No significant differences were found (p > 0.05) among those parameters when compared to MR information from T1FS images. Lymph nodes were demonstrated on MR images but distinction between benign and malignant nodes could not be made.

The extent and pattern of gastro-oesophageal reflux in patients with scleroderma oesophagus: the effect of low-dose omeprazole

Ambulatory 24-hour oesophageal pH studies were obtained from 11 patients with scleroderma who expressed either dysphagia (n = 6) or heartburn (n = 5) as their predominant oesophageal symptom. No significant differences were found in the extent of pattern of reflux between these two groups. The pH data of both scleroderma groups were combined and compared to an age- and sex-matched group of control subjects (n = 11). The reflux demonstrated by scleroderma patients was significantly greater than the control group in every category (P < 0.01). The percentage of time the pH was < 4.0 was not significantly different (P > 0.05) upright (29.9 +/- 19.8%) vs. supine (44.2 +/- 28.5%) in patients with scleroderma. Eight scleroderma patients underwent repeat pH studies while taking low-dose omeprazole (20 mg daily) and reflux was reduced significantly (P < 0.01) in all patients. The authors believe that 24-hour ambulatory oesophageal pH-monitoring should be routinely conducted in scleroderma patients to provide quantitative reflux data, even when heartburn is not expressed as a symptom. Omeprazole, 20 mg daily, provides adequate protection from the H+ component of the refluxate.

MRI in the diagnosis of Crohn's disease in two pregnant women

Two pregnant women considered symptomatic for inflammatory bowel disease were referred for magnetic resonance imaging (MRI) for assistance in establishing a diagnosis. Breath-hold gradient echo and contrast-enhanced T1-weighted fat-suppressed spin echo sequences were used. The MR appearance of the terminal ileum was consistent with Crohn's disease in both patients. The diagnosis of Crohn's disease was subsequently confirmed histologically. MRI is a safe, noninvasive modality that may be useful in confirming a suspected diagnosis of inflammatory bowel disease, especially in patients who cannot be evaluated with standard techniques.

Magnetic resonance imaging in inflammatory bowel disease

Magnetic resonance (MR) images were acquired in 28 consecutive inflammatory bowel disease (IBD) patients undergoing medical treatment. The protocol employed included i.v. gadopentatate dimeglumine, pre- and post-contrast breath-hold Fast Low Angle Shot (FLASH), and fat-suppressed spin echo imaging. The percent contrast enhancement (% CE) of the fat-suppressed images was compared with severity of inflammation based on endoscopic and/or surgical findings. The %CE of the contrast-enhanced images was 169% +/- 63 in cases of severe inflammation (n = 16), 97% +/- 38 in moderate inflammation (n = 8), and 49% +/- 26 in mild inflammation (n = 4). Significant correlations were found between the clinicopathologic findings and (a) % CE, r = 0.74 (p = 0.0001); (b) length of affected bowel segment, r = 0.49 (p = 0.007); and (c) bowel wall thickness, r = 0.42 (p = 0.02). In a subsequent comparison, %CE was correlated with length of affected bowel and bowel wall thickness. The best correlation was bowel wall thickness, r = 0.53 (p < 0.004). Good correlation was found between MR findings and pathology/histology findings in the determination of bowel wall thickness, length of diseased bowel, and severity of inflammation in 10 patients who underwent bowel resection. The results of this study show that MR images demonstrate the extent and severity of inflammatory changes in the GI tract, which correlate with endoscopic and histological findings.

Renal cancer staging: comparison of contrast-enhanced CT and gadolinium-enhanced fat-suppressed spin-echo and gradient-echo MR imaging

Fifty-three consecutive patients with 61 solid or complex non-fat-containing renal masses compatible with renal cancer were examined with contrast-enhanced computed tomography (CT) and magnetic resonance (MR) imaging with pre- and postcontrast FLASH (fast low-angle shot) and fat-suppressed spin-echo sequences. CT and MR imaging were performed within a 1-month interval. CT and MR images were prospectively interpreted. Tumor detection and staging were determined in all patients. CT and MR imaging enabled detection of 54 and 58 of 61 renal tumors, respectively. CT and MR imaging showed 34 and 35 of 38 histologically proved renal tumors, respectively, in 31 patients. Tumor size on CT and MR images demonstrated good correlation and correlated well with the size of pathologic specimens of 34 of 38 resected tumors detected with CT and MR imaging (r = .99). Of the 31 tumors in 31 patients who underwent surgical resection, 24 were correctly staged with CT and 29 with MR imaging. CT and MR imaging both enabled correct staging of four of five additional tumors with biopsy proof of tumor stage. A moderate difference in staging was observed between CT and MR imaging (P = .05). CT showed 13 and MR imaging 15 of 15 tumor thrombi. CT and MR imaging both showed 11 of 11 cases of adenopathy. The results suggest that MR imaging is moderately better than CT for the detection and staging of renal cancer.

Evaluation of adrenal masses with gadolinium enhancement and fat-suppressed MR imaging

A study was undertaken to determine the ability to characterize benign and malignant masses with unenhanced and contrast material-enhanced fast low-angle shot and fat-suppressed spin-echo magnetic resonance (MR) imaging. Thirty patients with adrenal masses detected at computed tomography (CT) underwent MR imaging within 14 days after CT. CT and MR images were interpreted in a prospective, blinded fashion. Sixteen patients had 20 benign adrenal masses, and 14 patients had 18 malignant masses. Quantitative measurements included percentage of contrast enhancement on immediate postcontrast dynamic images and periphery--center signal-to-noise ratio (S/N) on gadolinium-enhanced fat-suppressed images. Qualitative evaluation included determination of the regularity of lesion margins, homogeneity of signal intensity, and local extension. MR imaging depicted all adrenal masses discovered at CT examinations. Lesions ranged in diameter from 1 to 15 (mean, 4.4) cm. No significant difference was observed in percentage of contrast enhancement between benign (90.5% +/- 59.0 [standard deviation]) and malignant (110.5% +/- 116.4) masses. A difference was observed between periphery--center S/N for benign (-.05 +/- 1.5) and malignant (7.7 +/- 9.8) masses; overlap between the two, however, occurred. Qualitative evaluation allowed correct characterization of 32 of 38 masses, comparing favorably with CT, which allowed characterization of 30 lesions.

Islet cell tumors: comparison of dynamic contrast-enhanced CT and MR imaging with dynamic gadolinium enhancement and fat suppression

Ten patients with 11 islet cell tumors underwent dynamic contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging within a 1-month period. MR imaging depicted all 11 tumors, and CT depicted seven of the 11 tumors. CT did not depict four of seven tumors that measured 2.5 cm in diameter or less. Islet cell tumors had low signal intensity on T1-weighted fat-suppressed MR images, and gastrinomas were best shown with this technique. Two of three insulinomas less than 1.5 cm in diameter were best shown on dynamic contrast-enhanced fast low-angle shot (FLASH) images as uniform areas of high signal intensity. Hepatic metastases were seen in five patients and showed peripheral ringlike enhancement best demonstrated on dynamic gadolinium-enhanced FLASH images. Hepatic lesions were most conspicuous on T2-weighted fat-suppressed spin-echo images. MR imaging with dynamic gadolinium enhancement and fat suppression is a promising tool in the investigation of islet cell tumors.

T2-weighted MR imaging of focal hepatic lesions: comparison of various RARE and fat-suppressed spin-echo sequences

The authors prospectively compared four T2-weighted magnetic resonance (MR) sequences, including high-resolution 512 x 512 (matrix size) RARE (rapid acquisition with relaxation enhancement), 256 x 256 RARE, 128 x 256 breath-hold RARE, and 192 x 256 fat-suppressed spin-echo (T2FS) sequences, in the evaluation of 16 patients with focal hepatic masses. MR images were evaluated by quantitative lesion-liver signal difference-to-noise ratios (SDNRs) and subjective evaluation of image artifact and image quality. No significant differences were observed between RARE sequences in SDNR values. The T2FS sequence had a significantly higher SDNR than the 512 x 512 RARE sequence (24.6 +/- 15.0 vs 14.5 +/- 9.7) (P = .008). Image quality was rated highest for the 512 x 512 RARE and T2FS sequences (P = .006). The inherent advantage of high spatial resolution suggests that the 512 x 512 RARE sequence may be of value in detecting hepatic lesions.

Primary ovarian cancer: prospective comparison of contrast-enhanced CT and pre-and postcontrast, fat-suppressed MR imaging, with histologic correlation

Sixteen patients with clinically suspected malignant ovarian disease underwent contrast agent-enhanced computed tomography (CT) and magnetic resonance (MR) imaging in a prospective comparative study. MR imaging included fat-suppressed spin-echo and breath-hold FLASH (fast low-angle shot) before and after intravenous injection of gadopentetate dimeglumine. Histologic confirmation was obtained at laparotomy (n = 13) and biopsy (n = 3). Thirteen patients had histologically proven primary ovarian cancer. MR images showed the internal architecture of ovarian tumors better than CT in nine patients and equivalently in seven. MR images showed the relationship between ovarian tumors and adjacent pelvic structures (uterus [n = 9], sigmoid colon [n = 7], bladder [n = 7], and rectum [n = 3]) better than CT in nine patients and equivalently in seven. Intraabdominal extent of disease was better defined on MR than on CT images in nine patients, equivalently in six, and worse in one. Peritoneal metastases 1-2 cm in diameter were detected on MR images and missed on CT scans in six patients. In only one case did this result in a staging error with CT. The results suggest that MR imaging is at least equivalent and may be superior to CT in the evaluation of ovarian malignancy.

Chronic pancreatitis: MR imaging features before and after administration of gadopentetate dimeglumine

Magnetic resonance (MR) imaging was performed in patients with a history (> 1 year) of inflammatory pancreatic disease. Calcification was seen at recent computed tomographic examinations in 13 patients and was not seen in nine patients. On fat-suppressed spin-echo images, the signal-to-noise ratio of the pancreas was significantly lower (P < .001) in patients with pancreatic calcification (18.2 +/- 2.5 vs 38.1 +/- 6.1). On fast low-angle shot images, the percentage of contrast enhancement was also significantly lower (P < .001) in patients with calcification (26.1% +/- 5.8 vs 78.7% +/- 15.9). The results suggest that MR imaging may be useful in evaluating patients with a long history of pancreatic disease for the presence of irreversible disease.

Bile duct disease: prospective comparison of ERCP, CT, and fat suppression MRI

The authors compared computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP), techniques commonly used to study the biliary tree, with pre- and post-Gd-DTPA breath-hold fast low angle shot (FLASH) and fat suppressed spin-echo in 28 consecutive patients with bile duct abnormalities detected on ERCP, including 11 patients with malignant disease and 17 patients with benign disease. ERCP, CT, and magnetic resonance (MR) images were prospectively interpreted in a blinded fashion and reviewed by consensus. ERCP characterized all cases of malignant disease by the presence of a narrowed bile duct lumen with irregular margins. CT and MRI detected all cases of malignant disease and characterized nine of 11 as malignant. In seven of these cases, CT and MRI showed thickening of extrahepatic bile duct walls greater than 5 mm. MRI images showed intrahepatic-enhancing periportal tissue in four cases, which was not seen on CT images, and which was biopsy-proven tumor extension. Benign disease was characterized on ERCP images by the demonstration of smooth tapered narrowings in 16 cases, whereas on CT and MR images it was characterized by mild to moderate dilatation of the intrahepatic bile ducts and wall thickness less than 5 mm in 13 cases. Overall ERCP correctly characterized 27 cases as benign or malignant and CT and MRI both characterized 25. The results of this study show a trend that ERCP is superior to CT and MRI for characterizing bile duct disease.

Spleen: dynamic enhancement patterns on gradient-echo MR images enhanced with gadopentetate dimeglumine

To examine the pattern of immediate enhancement with gadopentetate dimeglumine on dynamic magnetic resonance (MR) images of the spleen, this study was divided into two parts: In the first part, the authors retrospectively reviewed the dynamic MR images obtained with a fast low-angle shot (FLASH) sequence in the abdomen immediately after injection of gadopentetate dimeglumine in 137 patients. In the second part, dynamic gadolinium-enhanced FLASH images were prospectively compared with contrast material-enhanced computed tomographic (CT) scans in 17 patients with focal splenic lesions discovered on CT scans. In the first part, 108 patients (79%) had an arciform pattern of contrast enhancement; 22 patients (16%), a uniform pattern of high signal intensity; and seven patients (5%), a uniform pattern of low signal intensity. Most patients had arciform enhancement of the spleen; uniform enhancement occurred in some patients with underlying malignant or inflammatory disease. In the second part, all focal lesions seen on CT scans were seen on dynamic MR images (75 lesions), significantly more than were seen on FLASH images (15 lesions) (P < .001).

Focal liver disease: comparison of dynamic contrast-enhanced CT and T2-weighted fat-suppressed, FLASH, and dynamic gadolinium-enhanced MR imaging at 1.5 T

Dynamic contrast medium-enhanced computed tomography (CT), T2-weighted fat-suppressed spin-echo (T2FS) magnetic resonance (MR) imaging, and breath-hold T1-weighted fast low-angle shot (FLASH) MR imaging before and after dynamic gadopentetate dimeglumine injection were compared in 73 patients with clinically suspected liver disease. Observer confidence for presence of focal lesions was determined by using receiver operating characteristic analysis. For all MR images, hepatic lesion-liver signal-to-noise ratios were evaluated qualitatively. and resolution and presence of artifacts were evaluated qualitatively. Lesion detection was greatest with T2FS (n = 272) and enhanced FLASH (n = 244) and was statistically greater with both of these than with CT (n = 220) and FLASH (n = 219) (P less than .03). Correct lesion characterization was greatest with enhanced FLASH (n = 236) (P less than .01), followed by CT (n = 199), FLASH (n = 164), and T2FS (n = 144). Enhanced FLASH was particularly successful in characterization of 5-mm- to 1.5-cm-diameter lesions as cystic or solid.

Cardiac masses: signal intensity features on spin-echo, gradient-echo, gadolinium-enhanced spin-echo, and TurboFLASH images

Fifteen patients with cardiac or paracardiac masses underwent magnetic resonance (MR) imaging with spin-echo (n = 15), cine gradient-echo (n = 15), gadopentetate dimeglumine-enhanced spin-echo (n = 15), and TurboFLASH (fast low-angle shot) (n = 7) sequences. All masses had either histologic confirmation (n = 11) or confirmation with other imaging modalities (n = 4). Myxomas (n = 6) were characterized by an intermediate signal intensity (SI) on spin-echo (n = 6) and low SI on cine gradient-echo (n = 6) images and moderately high-SI contrast enhancement (n = 5). Percent contrast enhancement for myxomas was 57% +/- 11%. Thrombus (n = 4) had intermediate (n = 3) or high (n = 1) SI on spin-echo images and low (n = 2) or intermediate (n = 2) SI on gradient-echo images and did not show substantial contrast enhancement. Postcontrast first-pass TurboFLASH images were useful by clearly demonstrating the nonenhancing mass lesion in a high-SI blood pool. Other cardiac and paracardiac tumors (n = 5) showed variable pre- and postcontrast spin-echo SI; however, no other tumor showed low SI on cine gradient-echo images.

Nasal CPAP reduces gastroesophageal reflux in obstructive sleep apnea syndrome

Anecdotal reports suggest that obstructive sleep apnea syndrome (OSAS) patients may suffer from frequent nocturnal gastroesophageal reflux (GER) and that nasal continuous positive airway pressure may be an effective form of antireflux therapy in this population. To confirm these clinical impressions, we performed two consecutive days of 24-h esophageal pH monitoring, nocturnal esophageal pressure recording, and polysomnography on six OSAS patients complaining of regular nocturnal GER. On night one, the patients were untreated. Five of six subjects had abnormal amounts of nocturnal GER. Arousal, movement and swallowing were more frequent (p less than 0.043) and nadir intrathoracic pressure lower (p less than 0.005) in the 30 s prior to precipitous drops in esophageal pH (greater than or equal to 2 pH units) than during random control periods. A direct association between obstructive apneas and GER was not identified. On night two, nasal CPAP was administered and successfully treated apnea in five of six subjects. In these patients, there was also dramatic reduction in GER frequency and duration on CPAP. The mean percentage of time pH less than 4 dropped from 6.3 +/- 2.1 to 0.1 +/- 0.1 percent (p less than 0.025). We believe that OSAS may predispose to nocturnal GER by lowering intrathoracic pressure and increasing arousal and movement frequency. Nasal CPAP can correct these predisposing factors and reduce GER.

Detection of acute and treated lesions of hepatosplenic candidiasis: comparison of dynamic contrast-enhanced CT and MR imaging

Dynamic contrast-enhanced computed tomography (CT) was compared with 1.5-T magnetic resonance (MR) imaging with FLASH (fast low-angle shot), gadolinium-enhanced FLASH (Gd-FLASH), and T2-weighted fat-suppression (T2FS) sequences in 11 patients with hematologic malignancies, five with biopsy-confirmed hepatosplenic candidiasis treated with antifungal chemotherapy and six with a clinical history suggestive of acute hepatosplenic candidiasis. CT and MR images were separately interpreted in a prospective fashion. MR imaging showed lesions compatible with candidiasis in the liver in six patients, the spleen in five, and the kidneys in one. CT showed candidiasis-compatible lesions in the liver in three patients and the spleen in one; no renal lesions were shown. Differences between acute and treated candidal lesions were observed. Gd-FLASH images showed the most liver lesions (n = 106), followed by FLASH (n = 85), T2FS (n = 20), and CT (n = 18). MR imaging performed better than CT in distinguishing candidal hepatic lesions from recurrent lymphoblastic lymphoma in one patient and from hepatic infarcts in another. The results suggest that MR imaging may be superior to CT in detecting lesions of hepatosplenic candidiasis.

Renal lesions: controlled comparison between CT and 1.5-T MR imaging with nonenhanced and gadolinium-enhanced fat-suppressed spin-echo and breath-hold FLASH techniques

Nonenhanced and gadolinium-enhanced fat-suppressed spin-echo and breath-hold fast low-angle shot (FLASH) magnetic resonance (MR) imaging techniques were compared with iodine contrast material-enhanced computed tomography (CT) for the detection and characterization of renal masses. MR studies included T1-weighted fat-suppressed spin-echo (T1FS) and FLASH images followed by rapid injection of gadopentetate dimeglumine and a repeated FLASH image obtained at 1 second, a T1FS image at 30 seconds, and a FLASH image at 10 minutes. Of 38 patients, 17 had renal cysts, 18 had solid tumors, two had cortical scarring, and one had a hypertrophied column of Bertin. With contrast-enhanced T1FS, contrast-enhanced FLASH, and CT images, 114, 110, and 109 lesions, respectively, were detected. With MR imaging and CT, cysts smaller than 5 mm in diameter and solid tumors as small as 1 cm in diameter were detected. With combined contrast-enhanced FLASH and T1FS images, 112 lesions were correctly characterized as cystic or solid; with nonenhanced T1FS images, 110; with nonenhanced FLASH images, 107; and with nonenhanced CT, 103.

Pancreatic disease: prospective comparison of CT, ERCP, and 1.5-T MR imaging with dynamic gadolinium enhancement and fat suppression

New magnetic resonance (MR) imaging techniques possess features desirable for imaging the pancreas. Computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP) were prospectively compared with breath-hold fast low-angle shot (FLASH) and fat-suppressed spin-echo techniques before and after enhancement with gadopentetate dimeglumine. Thirty-five patients underwent ERCP, CT, and/or MR imaging studies within a 1-month period. Correlation with surgical findings, histologic findings, or clinical and/or imaging follow-up was obtained in all cases. Quantitative measurements of pancreas, pancreas minus pancreatic lesion, and pancreas minus fat signal-to-noise ratios (SNRs) were performed on MR images. The highest measurements of pancreas minus pancreatic tumor SNR were on gadolinium-enhanced, fat-suppressed images (8.9 +/- 3.4). The 1-second postcontrast FLASH images most reliably showed enhancement of normal pancreatic tissue. Nonenhanced FLASH images depicted peripancreatic fluid and inflammatory changes most successfully. The findings from this study suggest MR imaging is effective for imaging inflammatory and neoplastic pancreatic disease and may be superior to CT.

Bowel disease: prospective comparison of CT and 1.5-T pre- and postcontrast MR imaging with T1-weighted fat-suppressed and breath-hold FLASH sequences

The potential of new high-field-strength magnetic resonance (MR) imaging sequences to evaluate bowel disease was investigated and compared with computed tomographic (CT) studies. Thirty-two patients were studied, 14 with known or suspected gastrointestinal tumors and 18 with known or suspected bowel inflammatory conditions. T1-weighted fat-suppressed spin-echo and breath-hold FLASH (fast low-angle shot) images were obtained before and after intravenous injection of 0.1 mmol/kg gadopentetate dimeglumine. Pathologic confirmation was obtained by biopsy (n = 18), surgical excision (n = 8), or endoscopy (n = 6). CT and MR images were analyzed separately in a prospective fashion and reviewed by consensus. Information from CT and MR images was comparable in cases of confirmed bowel neoplasia. CT scans had better spatial resolution, while fat-suppressed gadolinium-enhanced MR images had better contrast resolution. In the 18 cases of bowel inflammation, CT scans showed concentric wall thickening in 16, while MR images showed concentric wall thickening in 14 and increased contrast enhancement in 17. Contrast enhancement was better appreciated on fat-suppressed images than on FLASH images. The results suggest that MR imaging may play a role in the evaluation of bowel disease.

Esophageal reflux before and after isolated myotomy for achalasia

Four patients with achalasia underwent 24-hour esophageal pH measurements as ambulatory patients before and after limited myotomy without fundoplication. Resting lower esophageal sphincter pressure was reduced from 24.3 +/- 1.3 mm Hg to 7.5 +/- 4.3 mm Hg. No significant differences (p greater than 0.05) were found before and after operation in the total 24-hour pH data distribution (pH 6.24 +/- 0.84 vs 5.75 +/- 1.03), the fraction of time below pH 4.0 (4.8% +/- 5.3% vs 8.0% +/- 6.9%), or the mean duration of reflux episodes greater than 5 minutes (22.8 +/- 18.8 minutes vs 23.0 +/- 10 minutes), all +/- SD. Effective relief of esophageal obstruction in achalasia is feasible by isolated limited myotomy without producing gastroesophageal reflux.

Studies in esophageal motility: five year clinical experience in a Canadian tertiary care hospital

A total of 661 esophageal motility studies were performed in 568 patients over a five year period in a tertiary care hospital. Patients referred for investigation generally presented with one of three symptoms: dysphagia, reflux or chest pain. Dysphagia was more closely identified with organic esophageal dysfunction than other symptoms. Normal studies were recorded in 201 instances (30%). Studies demonstrating either a major or minor non-specific motor disorder were found in 380 cases (58%). Achalasia was found in 48 patients who underwent 65 procedures (10%). Scleroderma was diagnosed in 7 patients (1%). Elderly patients were not found to have diminished esophageal function when compared to a young group.

Seatbelt injury to the abdominal aorta

Seatbelt injury to the abdominal aorta is a rare finding with an unresolved mechanism. We present a case in which a rear-seat passenger wearing a lap belt was involved in a motor vehicle accident. Injuries sustained included a contused abdominal aorta. At the time of aortic repair, the involved segment was found to be atheromatous, had an intimal tear, and a flap that caused complete occlusion. Graft replacement was carried out employing a 12-mm DeBakey woven dacron prosthesis, which restored satisfactory circulation to both lower limbs. The patient developed myoglobinemia and subsequently died due to multiple organ failure 19 days following the accident. Tearing against the vertebral column, and bowel loop entrapment, in high-speed deceleration have been implicated as injury mechanisms as well as impingement by the belt or metal buckle, in such injuries. Also, our patient had existing atheromatous plaque, which was ruptured.

A new direct portosystemic collateral in canine portal hypertension

Two different models of extrahepatic portal obstruction were prepared in dogs to examine the development of portosystemic collateral pathways. The collateral pathways that developed were of two main types, portosplenic communications with the azygos system and a direct communication between the portal vein complex and the intrathoracic part of the inferior vena cava (IVC). This direct communication between the portal venous system and the IVC was unknown to us prior to these studies. The channel we describe has a potential for directly inducing pulmonary embolism, a possibility not seriously considered so far.

Reflux patterns in patients with achalasia without operation

Five patients with achalasia who had not had an operation underwent esophageal manometry and 24-hour, ambulatory pH monitoring to determine the pattern and extent of esophageal reflux. One patient had reflux within normal limits. In 2 patients, reflux occurred 0.5% of the total time and no episodes of supine reflux were recorded. In the 2 remaining patients, reflux was measured 16.8% and 55.3% of the total time; however, in both patients, these results were influenced by lengthy bouts of supine reflux. These indices of reflux were not influenced by differences in resting lower esophageal sphincter tone, position, or length. Twenty-four-hour esophageal pH monitoring can be useful in the preoperative assessment of patients with achalasia, and the information obtained might influence the choice of operative procedure.

Pseudocalculus of the common bile duct

Common-bile-duct growths are rarely identified unless they cause chronic biliary obstruction. This case report describes a 71-year-old woman who had jaundice and epigastric pain. A cholecysto-colonic fistula was demonstrated by endoscopic retrograde cholangiopancreatography. The patient also had multiple filling defects in the common bile duct. The fistula was closed and stones were removed. A postoperative cholangiogram showed two calculi. One was removed with a basket through the T-tube tract, but the second, which did not appear completely free of the common-duct wall, could not be removed by the basket method. Subsequently at laparotomy this was found to be a benign pedunculated polyp, composed of collagenous and vascular tissue and with no surface epithelium. Surgeons should bear in mind the possibility of a common-bile-duct growth in cases of extrahepatic biliary obstruction.

Prospective assessment of risk of bacteremia with colonoscopy and polypectomy

A prospective assessment was made of the frequency of positive blood cultures in patients undergoing colonoscopy with or without polypectomy. A total of 270 patients underwent 280 colonoscopies, of these, there were 105 patients that had 111 polypectomies. Blood cultures were taken prior to and within 15 min following each procedure. Six of 280 (2.1%) preprocedural blood cultures were positive. Seven of 169 (4%) blood cultures were positive within 15 min of insertion of the colonoscope in the colonoscopy only group. Eight of 223 (3.6%) blood cultures were positive within 10 min of the polypectomy. There was no clinical evidence of sepsis during the 24 hr following these procedures. In order to determine appropriate postprocedural sampling intervals, we induced a Staphylococcus epidermidis bacteremia with a mean of 1.16 X 10(6) colony forming units/ml on 10 occasions in seven dogs. Within 30 min of inoculation, we were able to detect only one colony forming unit/ml. The rate of positive blood cultures during colonoscopy alone and following polypectomy during colonoscopy is comparable to other gastrointestinal endoscopy procedures. The most optimal time to collect blood cultures in order to detect transient bacteremia is as soon after the procedure as is feasibly possible.

Endobronchial lipoma: report of three cases

Endobronchial lipomas are rare, benign lesions that usually obstruct a major bronchus and cause irreversible pulmonary damage distally. Because of the age, sex and smoking history of the patients in whom they are found, they also simulate malignant tumours. The authors report three cases of endobronchial lipoma. Two of the patients had a long history of cough and respiratory symptoms, the third was asymptomatic. Two patients underwent lung resection and one was managed by local resection through a bronchotomy. The lipoma in all three patients was diagnosed preoperatively and treated successfully.

Risk of bacteremia with endoscopic sphincterotomy

A prospective assessment of the risk of bacteremia with endoscopic sphincterotomy was made in 81 patients who underwent 95 procedures. Blood samples were taken for culture in all patients before and at 5 and 10 minutes after the last incision of the sphincter by the papillotome. An additional blood sample was obtained for culture within 30 seconds of the final incision in 32 of the 95 procedures. The rate of blood-culture positivity before the procedure was not significantly different from the post-incisional rate (1% compared with 3%, p greater than 0.05). No patient suffered from fever or chills during the 24 hours after sphincterotomy.

Giant villous adenoma of second portion of duodenum: case report

Villous adenomas of the duodenum are rare. In this report the authors describe the case of a 75-year-old woman who had an extensive adenoma involving the second portion of the duodenum and ampulla of Vater. The patient was successfully managed by a pancreaticoduodenectomy. The authors describe the histopathology of the lesion and suggest guidelines for surgical consideration.

Reflux patterns following limited myotomy without fundoplication for achalasia

Five patients with achalasia underwent limited myotomy without fundoplication. Surgery reduced mean lower esophageal sphincter resting pressure significantly (p less than .05) from 31 +/- 9.7 mm Hg to 16.1 +/- 8.2 mm Hg. Twenty-four-hour ambulatory esophageal pH studies demonstrated that the percentage of time the pH in the distal esophagus was below 4 was similar whether the patient was upright or supine (6.6 +/- 6.5% of total time upright vs. 9.1 +/- 12.7% of total time). Reflux events that occur in the supine position may be significant because of their prolonged duration resulting from the absence of normal secondary peristalsis in the body of the esophagus. Patients with achalasia who have undergone esophagomyotomy without fundoplication do not appear to experience more reflux than control subjects with normal esophageal function.

Changes in electrical potential difference of rectal mucosa and of gallbladder bile constituents of dogs fed chenodeoxycholic acid

Eighteen dogs were studied for 54 days. Rectal mucosal electrical potential difference (PD), gallbladder bile acids, cholesterol, and phospholipids were measured. It was shown that feeding chenodeoxycholic acid (CDCA) for 24 days in dosages of 15, 30, and 60 mg/kg of body weight, all depressed PD equally but significantly (P less than 0.05) in three groups of dogs compared with a control group. This depression was reversible 24 days after CDCA ingestion ceased in the two highest dosages. The low dose group was sacrificed after 24 days of CDCA feeding and the gallbladder bile was analyzed. CDCA and cholesterol were each significantly (P less than 0.05) elevated over control values in the gallbladder bile of these dogs. Phospholipids were not significantly changed. The PD, a reflection of Na+ -K+ ATPase activity, may be a useful indicator in maximizing dosages of CDCA in gallstone dissolution studies.