Long-Term Efficacy of Ethanol Ablation as Treatment of Metastatic Lymph Nodes From Papillary Thyroid Carcinoma.

CONTEXT: Ethanol ablation (EA) is considered an alternative to surgery for metastatic lymph nodes from papillary thyroid carcinoma (PTC) in selected patients. OBJECTIVE: The aim of this study was to evaluate the long-term efficacy and safety of this treatment. DESIGN AND SETTING: Adult patients with PTC who had received EA in lymph node metastasis at a tertiary referral center, and were included in a published study from 2011, were invited to participate in this follow-up study. METHODS: Radiologic and medical history were reviewed. Ultrasound examination of the neck was performed by radiologists, and clinical examination was performed by an endocrine surgeon. Response was reported according to predefined criteria for satisfactory EA treatment. Adverse events associated with EA were evaluated. Cause of death was reported for deceased patients. RESULTS: From the 2011 study, 51 of 63 patients were included. Forty-four patients were reexamined (67/109 lesions) and 7 patients were deceased. Median follow-up time from primary surgery was 14.5 years. Median follow-up from the latest performed EA in the 2011 study was 11.3 years. Local control was permanently achieved in most patients (80%). Recurrence within an ablated node was registered in 13 metastases in 10 patients. Seven of these patients also had recurrent disease elsewhere in the neck. No major side effects were reported. CONCLUSION: EA is a minimally invasive procedure with a low risk of complications. Our data suggest that EA is a safe and efficient treatment, providing excellent results for a large group of patients in the long term.

Early detection of complications in pancreas transplants by microdialysis catheters, an observational feasibility study.

BACKGROUND: Despite advances in immunosuppression and surgical technique, pancreas transplantation is encumbered with a high rate of complication and graft losses. Particularly, venous graft thrombi occur relatively frequently and are rarely detected before the transplant is irreversibly damaged. METHODS: To detect complications early, when the grafts are potentially salvageable, we placed microdialysis catheters anteriorly and posteriorly to the graft in a cohort of 34 consecutive patients. Glucose, lactate, pyruvate, and glycerol were measured at the bedside every 1-2 hours. RESULTS: Nine patients with graft venous thrombosis had significant lactate and lactate-to-pyruvate-ratio increases without concomitant rise in blood glucose or clinical symptoms. The median lactate in these patients was significantly higher in both catheters compared to non-events (n = 15). Out of the nine thrombi, four grafts underwent successful angiographic extraction, one did not require intervention and four grafts were irreversibly damaged and explanted. Four patients with enteric anastomosis leakages had significantly higher glycerol measurements compared to non-events. As with the venous thrombi, lactate and lactate-to-pyruvate ratio were also increased in six patients with graft surrounding hematomas. CONCLUSIONS: Bedside monitoring with microdialysis catheters is a promising surveillance modality of pancreatic grafts, but differentiating between the various pathologies proves challenging.

Portal vein reconstruction using primary anastomosis or venous interposition allograft in pancreatic surgery.

OBJECTIVE: Superior mesenteric vein/portal vein (SMV/PV) resection and reconstruction during pancreatic surgery are increasingly common. Several reconstruction techniques exist. The aim of this study was to evaluate characteristics of patients and clinical outcomes for SMV/PV reconstruction using interposed cold-stored cadaveric venous allograft (AG+) or primary end-to-end anastomosis (AG-) after segmental vein resections during pancreatic surgery. METHODS: All patients undergoing pancreatic surgery with SMV/PV resection and reconstruction from 2006 to 2015 were identified. Clinical and histopathologic outcomes as well as preoperative and postoperative radiologic findings were assessed. RESULTS: A total of 171 patients were identified. The study included 42 and 71 patients reconstructed with AG+ and AG-, respectively. Patients in the AG+ group had longer mean operative time (506 minutes [standard deviation, 83 minutes] for AG+ vs 420 minutes [standard deviation, 91 minutes] for AG-; P < .01) and more intraoperative bleeding (median, 1000 mL [interquartile range (IQR), 650-2200 mL] for AG+ vs 600 mL [IQR, 300-1000 mL] for AG-; P < .01). Neoadjuvant therapy was administered more frequently for patients in the AG+ group (23.8% vs 8.5%; P = .02). Patients with AG+ had a longer length of tumor-vein involvement (median, 2.4 cm [IQR, 1.6-3.0 cm] for AG+ vs 1.8 cm [IQR, 1.2-2.4 cm] for AG-; P = .01), and a higher number of patients had a tumor-vein interface >180 degrees (35.7% for AG+ vs 21.1% for AG-; P = .02). There was no difference in number of patients with major complications (42.9% for AG+ vs 36.6% for AG-; P = .51) or early failure at the reconstruction site (9.5% for AG+ vs 8.5% for AG-; P = 1). A subgroup analysis of 10 patients in the AG+ group revealed the presence of donor-specific antibodies in all patients. CONCLUSIONS: The short-term outcome of SMV/PV reconstruction with interposed cold-stored cadaveric venous allografts is comparable to that of reconstruction with primary end-to-end anastomosis. Graft rejection could be a contributing factor to severe stenosis in patients reconstructed with allograft.

Molecular signatures reflecting microenvironmental metabolism and chemotherapy-induced immunogenic cell death in colorectal liver metastases.

Background: Metastatic colorectal cancer (CRC) is associated with highly variable clinical outcome and response to therapy. The recently identified consensus molecular subtypes (CMS1-4) have prognostic and therapeutic implications in primary CRC, but whether these subtypes are valid for metastatic disease is unclear. We performed multi-level analyses of resectable CRC liver metastases (CLM) to identify molecular characteristics of metastatic disease and evaluate the clinical relevance. Methods: In this ancillary study to the Oslo-CoMet trial, CLM and tumor-adjacent liver tissue from 46 patients were analyzed by profiling mutations (targeted sequencing), genome-wide copy number alteration (CNAs), and gene expression. Results: Somatic mutations and CNAs detected in CLM were similar to reported primary CRC profiles, while CNA profiles of eight metastatic pairs suggested intra-patient divergence. A CMS classifier tool applied to gene expression data, revealed the cohort to be highly enriched for CMS2. Hierarchical clustering of genes with highly variable expression identified two subgroups separated by high or low expression of 55 genes with immune-related and metabolic functions. Importantly, induction of genes and pathways associated with immunogenic cell death (ICD) was identified in metastases exposed to neoadjuvant chemotherapy (NACT). Conclusions: The uniform classification of CLM by CMS subtyping may indicate that novel class discovery approaches need to be explored to uncover clinically useful stratification of CLM. Detected gene expression signatures support the role of metabolism and chemotherapy in shaping the immune microenvironment of CLM. Furthermore, the results point to rational exploration of immune modulating strategies in CLM, particularly by exploiting NACT-induced ICD.

A Novel Concept for Partial Liver Transplantation in Nonresectable Colorectal Liver Metastases: The RAPID Concept.

OBJECTIVE: Selected patients with nonresectable colorectal liver metastases benefit from liver transplantation and have acceptable 5-year survival rates. However, allocating full-sized grafts to this group of patients is difficult due to the scarcity of grafts. This could be improved by utilizing small partial grafts, which mandates effective strategies to overcome the problems regarding insufficient functional liver mass. METHODS: We have developed a protocol incorporating previously reported experiences from living donor transplantation and recent developments in liver surgery, facilitating transplantation of very small liver grafts. At the time of transplantation, segments 1 to 3 are resected in the recipient and orthotopically replaced by a segment 2 to 3 allograft. Portal inflow is modulated by redirecting the portal flow to the graft with concomitant focus on keeping the portal vein pressure below 20 mm Hg. A second-stage hepatectomy is performed as soon as the graft has regenerated to a sufficient volume. RESULTS: A graft weighing 330 g was transplanted to a 50-year-old man weighing 92 kg, and the portal vein to the right remnant liver was closed. The volume of the liver graft was doubled 2 weeks after the first procedure, and it increased further after the second procedure, with extended right hepatectomy performed at day 23 after transplantation. There were no signs of liver failure or small-for-size syndrome. CONCLUSIONS: The current protocol and ongoing study could represent a possible strategy to increase the availability of liver transplantation to patients with nonresectable liver tumors such as hepatocellular carcinoma and colorectal liver metastases.

Choosing the best reconstruction technique in abdominal computed tomography: a systematic approach.

OBJECTIVE: There is uncertainty regarding the effect of iterative reconstruction (IR) techniques and other reconstruction algorithms on image quality. The aim of this study was to optimize image quality in relation to radiation dose in computed tomography (CT) liver examinations by comparing images reconstructed with different abdominal filters with and without IR. METHODS: An anthropomorphic phantom was scanned on a Toshiba Aquilion ONE CT scanner. Images at 2 different dose levels were reconstructed with 12 different body reconstruction filters, all with both filtered back-projection and Adaptive Iterative Dose Reduction 3 dimensional. Receiver operating characteristic curves were constructed. The 2 reconstruction combinations with the highest scores from the phantom study were evaluated in a second comparison of clinical images. Six liver examinations were reconstructed with both filters and evaluated using visual grading analysis. RESULTS: Two combinations of reconstruction filters and IR were the only 2 options among the 8 best images at both dose levels (area under the curve, 0.96 and 0.94 for 15 mGy as well as 0.86 and 0.84 for 10 mGy). In the patient study, one of these filters in combination with IR scored slightly higher than the other in combination with IR (mean score, 2.60 and 2.57, respectively; P = 0.56). Iterative reconstruction did not significantly increase lesion detectability for any of the filters. CONCLUSIONS: This study indicates that the preferred choice for reconstruction of CT liver examinations performed with the Toshiba Aquilion ONE should be the FC18 filter with IR, although the IR technique did not significantly improve lesion detectability and did not compensate for the dose reduction in this study.

PET-CT in the assessment of lung cancer at Rikshospitalet from 2007-2011.

BACKGROUND: PET-CT is an aid in the assessment of lung cancer for identifying operable patients. The examination is recommended for most patients with non-small cell lung cancer whom the primary assessment has indicated may have a curable disease. The aim was to assess the usefulness of PET-CT for patients assumed to be operable who underwent an examination at Rikshospitalet. MATERIAL AND METHOD: Patients admitted for lung cancer assessment are registered consecutively in the department's quality database. We analysed data for the period 2007-2011 for patients whom a primary assessment had revealed to have a potentially operable tumour. For capacity reasons, some patients underwent surgery without a prior PET-CT. RESULTS: Of 651 potentially operable patients, 533 had had a PET-CT scan of which 403 (76%) had undergone surgery. We calculated that the examination had a sensitivity of 78% (95% CI 70-86) and specificity 88% (95% CI 85-91%), positive predictive value 64% (95% CI 55-72) and negative predictive value 94% (95% CI 91-96) for spreading to mediastinal lymph nodes. Diagnostic accuracy was 86% (95% CI 83-89) with kappa agreement 0.61 (95% CI 0.53-0.69) between PET-CT and actual findings of malignant or benign mediastinal lymph nodes. INTERPRETATION: PET-CT was a useful tool for selecting potentially operable lung cancer patients at Rikshospitalet in the period 2007-2011. Provided that the population we scan with PET-CT does not change, patients with a negative PET-CT can with few exceptions be referred directly for surgery without further invasive assessment.

Color Doppler ultrasound-guided transducer compression of post biopsy bleeding of kidney transplants.

BACKGROUND: Color Doppler ultrasound (CDUS) has a potential of early detection of post biopsy bleeding. We describe CDUS guidance in planning, acquisition, and, in the case of bleeding, compression of the needle tract in biopsy procedures of kidney transplants. METHODS: Eighty-three kidney transplant biopsy procedures performed on clinical indication were performed in 71 adult patients, 25 women, mean age 51 years, using CDUS and 18-G biopsy needles. Bleeding needle tracts were compressed using CDUS guidance. RESULTS: CDUS immediately detected blood leakage and facilitated compression of the bleeding needle tract in 34 (41%) of the 83 procedures, including 53 (25%) of 215 needle passes. In 34 bleeding procedures, the mean duration of the longest bleeding time after a needle pass was 124 seconds (median, 20 seconds; range, 3-1440 seconds). In 12 of these procedures (35%), the bleeding time was 30 seconds or more. In six procedures (18%), a bleeding of 120 seconds or more was observed. Complications included seven small hematomas. Five hematomas developed in procedures where the longest duration CD bleeding was 120 seconds or more. CONCLUSIONS: CDUS detects bleeding and facilitates direct transducer compression of the needle tract in a substantial portion of biopsy procedures of kidney transplants. Only minor hematomas occurred.

Diagnostic accuracy of computed tomography and histopathology in the diagnosis of usual interstitial pneumonia.

BACKGROUND: The relative clinical benefit of histopathology and computed tomography (CT) in patients with idiopathic interstitial pneumonia (IIP) is under debate. PURPOSE: To analyze thin-section CT features and histopathologic findings in patients with usual interstitial pneumonia (UIP) in the clinical context of idiopathic pulmonary fibrosis (IPF), and to evaluate and compare diagnostic accuracy of the two methods among patients with an appropriate spectrum of IIP. MATERIAL AND METHODS: The study included 91 patients (49 men; mean age 53.2 years; median follow-up 7.2 years) with clinically suspected interstitial lung disease. All underwent surgical lung biopsy and thin-section CT. Two independent readers retrospectively assessed the CT images for the extent and pattern of abnormality and made a first-choice diagnosis. Two pathologists retrospectively assessed the histopathologic slides. In 64 patients with IIP, a retrospective composite reference standard identified 41 patients with UIP. CT characteristics of UIP and IIPs other than UIP were compared with univariate and multivariate analyses. RESULTS: There was good agreement between the readers for the correct first-choice CT diagnosis of UIP (κ = 0.79). The sensitivity, specificity, and positive predictive value of the CT diagnosis of UIP were 63%, 96%, and 96%, respectively. The sensitivity, specificity, and positive predictive value of the histological diagnosis of UIP were 73%, 74%, and 83%, respectively. The CT feature that best differentiated UIP from IIPs other than UIP was the extent of reticular pattern (odds ratio, 5.1). CONCLUSION: Surgical lung biopsy may not be warranted in patients with thin-section CT diagnosis of UIP.

Non-invasive assessment of renal allograft fibrosis by dynamic sonographic tissue perfusion measurement.

BACKGROUND: Chronic allograft nephropathy (CAN) characterized by interstitial fibrosis and tubular atrophy is a major cause of renal transplant failure. The diagnosis can currently only be verified by a graft biopsy. PURPOSE: To evaluate whether non-invasive dynamic color Doppler sonographic parenchymal perfusion measurements are different in grafts with various degrees of biopsy proven renal transplant fibrosis. MATERIAL AND METHODS: Forty-nine adult patients were prospectively included. Four patients were excluded. Color Doppler videos from the renal cortex were recorded. Perfusion in the renal cortex was evaluated using a software package which calculates color pixel area and flow velocity, encoded by each pixel inside a region of interest of a video sequence. The software calculates parameters that describe tissue perfusion numerically. Two of these, the perfusion intensity and tissue pulsatility index, were compared to grade of interstitial fibrosis (0-3) in biopsies. Observer agreement was evaluated in a subset of 12 patients. RESULTS: Of the 45 patients analyzed, 18 patients had grade 0, 18 had grade 1, seven had grade 2 and two had grade 3 fibrosis. The mean perfusion intensity of grade 0 was significantly higher than that of grade 2 and 3 fibrosis in the proximal cortical layer (1.65 m/s vs. 0.84 m/s, P = 0.008). No significant difference was found between grade 0 and grade 1 fibrosis. Perfusion intensity was correlated to estimated glomerular filtration rate (Pearson r 0.51, P = 0.001, R(2) = 0.26 and 0.46, P = 0.001, R(2) = 0.22 in the distal and proximal cortex, respectively). Inter-observer agreement of the perfusion intensity, expressed as intraclass correlation coefficient was 0.69 in the proximal part of the cortex. Intra-observer agreement was 0.85 for observer 1 and 0.82 for observer 2. CONCLUSION: Perfusion intensity assessed by dynamic color Doppler measurements is significantly reduced in allografts with grade 2 and 3 fibrosis compared to allografts without fibrosis. Further studies involving longitudinal assessment of allografts undergoing protocol biopsies would be of interest.

White matter lesion load increases the risk of low CSF Aß42 in apolipoprotein E-ɛ4 carriers attending a memory clinic.

BACKGROUND: White matter lesions (WMLs) are age-related manifestations of ischemic cerebrovascular disease and increase the risk for Alzheimer's disease (AD). The apolipoprotein E (ApoE) ɛ4 allele is a risk factor for late onset AD and has been related to low cerebrospinal fluid (CSF) Aß42 levels and to cerebrovascular disease. The present study analyzed the relationship between WMLs, ApoE-ɛ4 genotype, and low CSF Aß42. METHODS: A total of 235 memory clinic attenders were stratified in 3 groups according to WML load. WMLs were rated on axial T2 magnetic resonance imaging images. Group 1 had no or only small amounts of periventricular (PV) or subcortical (SC) WMLs, WML group 2 had high amounts of PV WMLs and low amounts of SC WMLs, and WML group 3 had high amounts of both PV and SC WMLs. In each WML group, ApoE-ɛ4 genotype was used in logistic regression as a predictor for low CSF Aß42 (cutoff≤450 ng/L). RESULTS: The odds ratio (OR) of having low CSF Aß42 was significantly increased in the presence of ApoE-ɛ4 only in WML group 3 (OR 3.69, P=.009). CONCLUSION: A high WML load may interact with the ApoE-ɛ4 genotype and increase the risk for reduced CSF Aß42 in patients attending a memory clinic.

Clinical utility of microbubble contrast-enhanced ultrasound in the diagnosis of hepatic artery occlusion after liver transplantation.

To evaluate the frequency of use and the diagnostic accuracy of real-time contrast-enhanced ultrasound (CEUS) in the diagnosis of hepatic artery occlusion after liver transplantation. One hundred and fifty-two liver transplantations in 142 adult subjects, comprising 80 male patients and 62 female patients, were studied. After surgery, liver circulation was routinely assessed by conventional Doppler ultrasound (US). Wherever the examiners were not confident about the state of the circulation, CEUS was performed with one or more doses of a sulfur hexafluoride (SF-6)-containing second-generation contrast agent intravenously. Clinical follow up including repeat Doppler US, computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) of the liver vasculature were used as reference standards. During the first month after transplantation, Doppler US was inconclusive with regard to patency of the hepatic artery (HA) circulation in 20 (13 %) of 152 transplantations. CEUS was performed in these patients, and detected six cases of HA thrombosis (HAT) in five transplants. CEUS correctly ruled out HA occlusion in 15 transplants. All HA occlusions occurred during the first 14 days after transplantation. In the subset of transplantations examined with CEUS, the sensitivity, specificity and accuracy of CEUS were 100%. In approximately 13% of cases, conventional Doppler US did not provide sufficient visualization of the HA after liver transplantation. In these cases, correct diagnosis was achieved by supplementary CEUS.

White matter lesion subtypes and cognitive deficits in patients with memory impairment.

AIM: To analyze the relationship between periventricular (PV) and subcortical (SC) white matter lesions (WML) and cognitive function in patients with memory impairment. METHODS: In total, 253 patients with Global Deterioration Scale scores >or=3 who had been referred to a university-based memory unit due to memory complaints were included (mean age 69.7 years, 124 females). Cognitive function was assessed with the Mini-Mental State Examination (MMSE) and the Neurobehavioral Cognitive Status Examination (Cognistat), and full test results were available for 217 patients. PV and SC WML loads (semi-quantitative rating on axial T(2)-weighted MRI scans) were used in linear regression as predictors of cognition. RESULTS: MMSE was significantly correlated with SC WML (p = 0.005), but not with PV WML (p = 0.19). Cognistat tests for orientation, comprehension, visuoconstruction, calculation, similarities, and judgment were negatively correlated with SC WML (p < 0.01), as was verbal memory with parieto-occipital SC WML (p < 0.05). Visuoconstruction and calculation were negatively correlated with PV WML (p < 0.05). Parieto-occipital WML were more strongly related to cognition than fronto-temporal WML. Only SC WML were significantly correlated with cognition when PV and SC WML were entered simultaneously in the regression model. CONCLUSION: In patients with cognitive impairment, SC WML, in particular in parieto-occipital regions, were associated with reduced cognitive function.

MRI of the small bowel with oral contrast or nasojejunal intubation in Crohn's disease: randomized comparison of patient acceptance.

OBJECTIVE: Magnetic resonance imaging of the small bowel with an oral contrast (MRI per os) is believed to generate fewer adverse symptoms compared with installation of the contrast in a nasojejunal catheter (MRE). However, there is very little evidence to support this assumption. The aim of this study was to evaluate the compliance of patients examined with both of these MRI methods. MATERIAL AND METHODS: Patients with suspected or known Crohn's disease referred for MRI of the small bowel underwent both MRI per os and MRE within 7 days. A questionnaire was answered immediately and 24 h after the procedure. Adverse symptoms were graded on a visual analogue scale (VAS). Responses were compared with paired and independent sample t-tests and signed-rank tests. Correlation of each symptom to the overall discomfort was evaluated with Spearman's correlation coefficient. RESULTS: Thirty-eight patients (18 F, 20 M) were included in the analysis. Abdominal pain and discomfort were lower with MRI per os than with MRE (mean VAS pain score immediately after: 10 mm and 33 mm, respectively, p < 0.001; mean VAS discomfort score 24 h after: 18 mm and 62 mm, respectively, p < 0.001). Nausea and abdominal pain were correlated with overall discomfort after MRI per os (r = 0.56 for both, p < 0.001). No symptoms were significantly correlated with discomfort experienced with MRE. More patients accepted repeat MRI per os examination (n = 36) than MRE (n = 22, p = 0.001). CONCLUSION: Patients preferred and experienced less abdominal pain and discomfort with MRI per os than with MRE.

[Urography findings after total cystectomy and urinary diversion]. / Urografifunn etter total cystektomi og urinavledning.

BACKGROUND: Urinary tract obstruction may damage the kidneys, but the interpretation of intravenous urograms is difficult after a total cystectomy for bladder cancer. There is a need for practical guidelines for image reading. MATERIAL AND METHODS: Urograms were routinely taken to control 20 patients (18 men) who had been operated for bladder cancer with total cystectomy and urinary diversion between 1999 and 2004. All patients were examined one or several times at irregular time intervals after surgery. 18 patients were examined within six months after surgery, of whom six were also examined later. Two patients were only examined after six months. Two radiologists reviewed the postoperative urograms by first filling in a standardised form independently of each other and thereafter by filling in the form together according to consensus. The extent of dilatation of the collecting system (calyces, kidney pelvis and ureter) was graded as none, mild, moderate or severe for each side separately. RESULTS: At the first follow-up within six months, six of 18 patients had developed moderate or severe and 10 mild dilatation of the collecting system. The left side was more often dilated (n=7) than the right one (n=1). Both sides were dilated for eight patients; to a moderate/severe degree for two and to a mild degree for six. Of the six patients who were also examined more than 6 months after surgery; one had moderate/severe persistent dilatation and showed signs of regression, three had mild dilatation (two of whom had remission) and two had no dilatation after six months. The patient with a persistently dilated collecting system lost one kidney on the left side despite insertion of a draining ureteral stent. There was a good interobserver agreement concerning the grade of dilatation. INTERPRETATION: Mild dilatation of the collecting system is common after cystectomy and urinary diversion, especially on the left side, and will normalize within a few months in most patients. Persistent dilatation may signify a pathological condition, especially in combination with other radiological findings, such as delayed contrast excretion and obstructed passage in late images.

Intestinal gas in plain abdominal radiographs does not correlate with symptoms after lactulose challenge.

OBSERVATION: Intestinal gas production and abdominal discomfort can be triggered by the ingestion of carbohydrates such as lactulose. Using plain abdominal radiographs, we studied whether subjective complaints after a lactulose breath test would be quantitatively related to intestinal gas volumes. METHODS: Abdominal symptoms after the breath test were quantified by a written questionnaire and gas volumes were scored in plain abdominal radiographs, in 50 consecutive patients with unexplained, irritable bowel syndrome-like symptoms. Breath excretion of hydrogen and methane was determined in all patients. RESULTS: Forty-two (84%) of the patients claimed that their post-breath test symptoms were a true replicate of their customary discomfort. Total symptom scores (sum of scores for pain/discomfort, borborygmi, bloating, diarrhea, constipation) or any specific symptom score were not significantly correlated to gas volume scores (r=-0.04; P=0.8 for total symptom score). The 13 (26%) methane producers had significantly higher mean gas volume scores compared with nonproducers (0.38 vs. 0.24; P=0.0008), but fewer symptoms (total symptom score 11.9 vs. 18.2; P=0.17). CONCLUSION: Intestinal gas volume, as scored in plain abdominal radiographs, is not correlated with abdominal discomfort after lactulose challenge. Intestinal gas may not be the major cause of abdominal discomfort following carbohydrate ingestion in patients with functional gut disorders.