Evaluation of upper gastrointestinal tumors with a new endoscopic ultrasound probe

Mini-probe ultrasonography for the staging of colon cancer: a systematic review and meta-analysis

AIM

With an increasing array of treatment modalities available for colon cancer, it is increasingly important to stage tumours accurately to allocate the appropriate management. This study evaluated the accuracy of mini-probe endoscopic ultrasound (EUS) in assigning clinical stage to colon cancer.

METHOD

An electronic search was performed in January 2013 using the Embase, MEDLINE and Cochrane databases. This was supplemented by a hand search of published abstracts from scientific meetings. Trials evaluating the accuracy of the mini-probe EUS compared with histopathological grade in determining the clinical stage of colon cancer were included in this pooled analysis. The main outcome measures included accuracy, sensitivity and specificity for T and N staging.

RESULTS

Ten studies were identified which compared the mini-probe EUS staging of 642 colon or rectal cancers with the histopathological specimen. The pooled sensitivity and specificity for staging were 0.91 and 0.98 for T1 tumours, 0.78 and 0.94 for T2 tumours, 0.97 and 0.90 for T3/T4 tumours and 0.63 and 0.82 for nodal staging. Eight per cent of T1/T2 tumours were upstaged to T3/T4 tumours and 5% of T3/T4 tumours were downstaged.

CONCLUSION

Mini-probe EUS is highly effective for assigning clinical stage in colon cancer and in identifying patients who may be suitable for nonsurgical treatment including neoadjuvant chemotherapy or endoscopic resection.

High-frequency mini-probe ultrasound as a useful adjunct in the management of patients with malignant colorectal polyps

AIM

Colorectal polyps with a focus of malignancy, identified postpolypectomy, pose a management challenge of whether endoscopic treatment is adequate or whether further surgical resection is required. This study assessed 12- and 20-MHz colonoscopic ultrasound to evaluate the presence of residual disease and local lymph nodes.

METHOD

Consecutive cases of all colorectal polyps with a focus of malignancy were included. Colonoscopic high-frequency ultrasound was performed (20-MHz mini-probes for residual polyps and 12-MHz ultrasound for local lymph nodes) in the region of previous polypectomy. Biopsies were taken of the polypectomy site if any abnormalities were seen.

RESULTS

Twenty-one malignant polyps (sigmoid, n = 10; rectum, n = 8; transverse colon, n = 1; ascending colon, n = 1; and caecum, n = 1) were identified. All were invasive adenocarcinomas; 12 were intramucosal and nine were submucosal (seven sm1 lesions in the upper third of the submucosa; and two sm2 lesions in the middle third of the submucosa). Excision was histologically complete in 12 patients, four had involved margins and histology was uncertain in five owing to diathermy artefacts. Further colonoscopy revealed a residual abnormality in eight patients. The 12- and 20-MHz ultrasound imaging revealed mucosal irregularity with normal bowel-wall layers and no lymph-node involvement, with normal histology. High-frequency ultrasound was normal in the remaining 13 patients. At the time of writing, 15 (72%) of the 21 patients were disease free without further surgery. Six of the 21 patients underwent surgery, despite normal high-frequency ultrasound findings, because of submucosal invasion (sm1 or sm2) and uncertain completeness of resection. The specimens were free of cancer in all six patients.

CONCLUSION

High-frequency ultrasound is feasible for the assessment of colorectal malignant polyps.

Colonoscopic high frequency mini-probe ultrasound is more accurate than conventional computed tomography in the local staging of colonic cancer

AIM

Colonoscopic high frequency mini-probe ultrasound was compared prospectively with CT in the local staging of colonic cancer.

METHOD

Consecutive patients undergoing surgical resection for colonic cancer were recruited. Preoperative 64-slice CT staging with multiplanar reconstruction was compared with colonoscopic high frequency mini-probe ultrasound using 12 MHz and 20 MHz probes. The three methods of staging (CT, 12 MHz ultrasound and 20 MHz ultrasound) were compared with the histological stage of the resected specimen. This was done using weighted kappa coefficients where weights of 0.7-0.8 were given to penalize disagreements of one level in either direction and weights of zero were given to penalize disagreements of more than one level in any direction.

RESULTS

In total, 38 patients with colonic cancer were included. They were located in the sigmoid (n = 20), descending (n = 5), ascending (n = 2) and transverse colon (n = 1) and in the caecum (n = 7) and splenic (n = 2) and hepatic (n = 1) flexure. Histopathological assessment revealed seven pT1, four pT2, 25 pT3 and two pT4 cancers. In relation to the pathology the weighted kappa coefficients were 0.36 (SE = 0.14), 0.81 (SE = 0.16) and 0.81 (SE = 0.17) for CT, ultrasound 12 MHz and ultrasound 20 MHz. Histopathologically 15 (39.5%) patients were lymph node positive. The sensitivity, specificity and kappa coefficient for detection of nodal disease for CT were 80%, 47.8% and 0.25 (SE = 0.14) compared with 80%, 82.5% and 0.62 for 12 MHz ultrasound (SD = 0.14) and 23%, 90.5% and 0.15 (SD = 0.13) for 20 MHz ultrasound.

CONCLUSION

Colonoscopic ultrasound is significantly more accurate than CT for T staging of colonic cancers. With respect to nodal status, 12 MHz ultrasound offers superior accuracy to CT or 20 MHz ultrasound.

Accuracy of high-frequency catheter-based endoscopic ultrasonography according to the indications for endoscopic treatment of early gastric cancer

BACKGROUND AND AIM

The development of endoscopic treatment, such as endoscopic submucosal dissection, extends the indications for endoscopic resection in patients with early gastric cancer (EGC). Endoscopic ultrasonography (EUS) is the first-choice imaging modality for determining the depth of invasion of gastric cancer. The aim of the present study was to prospectively assess the accuracy of EUS for determining the depth of EGC, according to the accepted/extended indications.

METHODS

We prospectively included a total of 181 lesions in 178 patients, with an endoscopic diagnosis of EGC, who underwent EUS for staging the depth of tumor invasion using a 20-MHz catheter probe. We investigated the accuracy of EUS for determining the depth of endoscopically-suspected EGC and then analyzed the difference in the accuracy of EUS according to the accepted/extended indications.

RESULTS

Of the 178 patients, five patients were dropped because of the absence of final histological results. For the 176 lesions in 173 patients, the accuracy of EUS assessment for the depth of tumor invasion was 80.7% (142 of 176 lesions). The accuracy of EUS for the lesions with accepted indications and with extended indications was 97.6% (40 of 41 lesions) and 83.6% (46 of 57 lesions), respectively (P = 0.040). Of the lesions with extended indications, the accuracy of EUS decreased especially for the lesions with ulceration and those with minute submucosal invasion (79.2% and 42.9%, respectively).

CONCLUSIONS

The accuracy of EUS for the lesions with the extended indications was lower than that for the lesions with the accepted indications. In particular, lesions with ulceration and minute submucosal invasion should be carefully considered prior to endoscopic treatment by pretreatment EUS staging.

The accuracy of endoscopic ultrasonography in differentiating mucosal from deeper gastric cancer

BACKGROUND AND AIM

With the advent of endoscopic mucosal resection and endoscopic submucosal dissection techniques, pretreatment differentiation between mucosal and deeper gastric cancer has become increasingly important. The aim of this study was to systematically review published data on the diagnostic performance of endoscopic ultrasonography (EUS) in differentiating between mucosal and deeper gastric cancer.

METHODS

A systematic search for relevant studies was performed of the PubMed/MEDLINE and Embase databases. Two reviewers independently assessed the methodological quality of each study. Sensitivity and specificity of EUS were calculated for each study and a summary receiver operating characteristic curve (sROC) was constructed. Subgroup analyses were performed if results of individual studies were heterogeneous.

RESULTS

The inclusion criteria were met by 18 studies. The studies had poor methodological quality. Sensitivity and specificity of EUS in detecting cancerous extension beyond the mucosa ranged from 18.2 to 100% (median 87.8%) and from 34.7 to 100% (median 80.2%), with an area under the sROC of 0.8924. There was significant heterogeneity in both sensitivities and specificities among the included studies (P < 0.0001). Studies which only included patients endoscopically suspected of having EGC and studies which only used transducer frequencies > or =15 MHz were homogeneous in sensitivities (P= 0.1828 and 0.4501, respectively).

CONCLUSION

It is unclear yet whether EUS can accurately differentiate between mucosal and deeper gastric cancer. Factors that may influence its diagnostic performance should be further explored.

Diagnostic ability of high-frequency ultrasound probe sonography in staging early gastric cancer, especially for submucosal invasion

BACKGROUND

Advances in gastrointestinal endoscopy have resulted in endoscopic mucosal resection becoming the main therapy for many early gastric cancers confined to the mucosa and, in some cases, of minimal submucosal invasion. Thus, preoperative determination of the depth of the cancer is important. We compared the results of high-frequency ultrasound probe sonography with those of histologic study to clarify the usefulness of identifying of submucosal invasion and determining the depth of early gastric cancer.

METHODS

Subjects were 295 patients diagnosed with early gastric cancer who had undergone endoscopic mucosal or surgical resection. High-frequency ultrasound probe sonographic findings were compared with histologic findings.

RESULTS

The muscularis mucosae was visualized in 63% of cases of early gastric cancer. By construction on receiver operator characteristics curve, we determined that submucosal invasive cancer could be diagnosed by high-frequency ultrasound probe sonography to a depth of about 600 microm. There was no case in which invasion deeper than 1000 microm was diagnosed as a hypoechoic area limited to the mucosal layer or a fan-shaped hypoechoic area in the submucosal layer. The depth of early gastric cancer was accurately determined in 90% of cases.

CONCLUSIONS

High-frequency ultrasound probe is a useful tool for accurately determining the depth of invasion of early gastric cancer when its limitations are understood.

Prospective evaluation of a jelly-like conducting medium for catheter US probe imaging of esophageal and duodenal lesions

BACKGROUND

The catheter probe EUS(C-EUS) relies on luminal water for acoustic coupling. However, in tubular structures, such as the esophagus and the duodenum, instilled water drains away rapidly. The use of water-filled balloons is limited by air artifact and other problems. This study evaluated the image quality, the penetration depth, the tumor staging accuracy, and the safety of C-EUS by using carboxymethylcellulose, an edible, nontoxic, transparent jelly-like substance (JC-EUS).

METHODS

Forty patients with an esophageal or a duodenal submucosal lesion or an esophageal carcinoma were evaluated prospectively in a crossover study with both C-EUS and JC-EUS when using a 12-MHz US catheter probe. Based on still images, depth of US penetration and image quality (by using a predefined 1 to 5 scale) were assessed by a blinded, independent endosonographer.

OBSERVATIONS

JC-EUS was superior in image quality compared with C-EUS overall (mean score: 4.9 vs. 2.6; p <0.001), as well as in each subgroup (esophageal carcinoma, esophageal submucosal lesion, duodenal submucosal lesion). Penetration depth was not significantly different (2.5 cm). Staging was 100% accurate in 14 patients with esophageal cancer who underwent surgery. There was no procedure-related complication.

CONCLUSIONS

JC-EUS is safe, provides superior image quality to C-EUS, and is accurate for local staging of esophageal cancer.

Prospective comparison of catheter-based endoscopic sonography versus standard endoscopic sonography: evaluation of gastrointestinal-wall abnormalities and staging of gastrointestinal malignancies

PURPOSE

Endoscopic sonography (EUS) is an important imaging modality for evaluating benign and malignant luminal gastrointestinal-tract abnormalities. The objectives of this study were to evaluate the feasibility of catheter-based EUS (C-EUS) during standard upper and lower endoscopy in patients with malignancies and other abnormalities of the gastrointestinal-tract lumen, to assess the image quality obtained with the 12.5-MHz catheter-based ultrasound transducer, and to prospectively compare the interpretations of C-EUS images with those of the standard EUS (S-EUS) images.

METHODS

One hundred thirty-seven consecutive patients referred for EUS were evaluated with C-EUS followed by S-EUS. The patients were assigned to 1 of 2 groups: group A, patients with intramural masses or intestinal wall thickening, with biopsies negative for malignancy; and group B, patients with esophageal, gastric, duodenal, or rectal cancer referred for staging. The results of C-EUS and S-EUS were compared for each group.

RESULTS

C-EUS was completed in 134 patients: 81 patients with 83 lesions in group A and 53 patients in group B. For group A, C-EUS image interpretation concurred with that of S-EUS in 74 (89%) of 83 lesions. For group B, C-EUS concurred with S-EUS for tumor depth (T) and nodal (N) classifications in 19 cases (36%) and 26 cases (49%), respectively. The depth of invasion was underestimated by C-EUS in all 34 cases in which the T classifications by C-EUS and S-EUS were discordant. In 1 of 6 patients with stenotic cancer that was nontraversable by S-EUS, C-EUS identified lymphadenopathy (incorrectly classified as N0 by S-EUS).

CONCLUSIONS

C-EUS was easily performed, and the C-EUS images were comparable to the S-EUS images in assessing mucosal and intramural lesions. The limited depth of penetration of the catheter-based transducer resulted in understaging the extent of tumor invasion and underestimating the nodal spread.

Imaging of esophageal tumors with a water-filled condom and a catheter US probe

BACKGROUND

High-frequency catheter ultrasound (C-EUS) probes provide high resolution images of the gastrointestinal tract. Their use in the esophagus is limited by the requirement for a water-filled lumen for good acoustical coupling. We have developed a system using a condom that provides a continuous column of water for high resolution C-EUS imaging of the esophagus.

METHODS

Nine patients underwent condom C-EUS for evaluation of esophageal mucosal and submucosal tumors. A standard latex condom was attached to a 2-channel endoscope and filled with water after esophageal intubation. A 20 MHz C-EUS probe placed within the water-filled condom was used to characterize all lesions.

RESULTS

The condom C-EUS system provided a 360 degree, high resolution image throughout the length of the esophagus without air artifact and without the risk of aspiration associated with filling the esophageal lumen with water. Complete imaging of the tumor was obtained in all cases, and no additional C-EUS procedures were required. The condom C-EUS was subjectively rated superior overall in comparison to standard C-EUS by 4 independent endosonographers.

CONCLUSIONS

Condom C-EUS is a new method of high resolution imaging of the esophagus. This method provides a contained column of water within the esophagus that improves image quality and ease of use and may reduce the risk of aspiration.

Gastrointestinal miniprobe sonography: the current status

Endoscopic ultrasonography (EUS) represents a major advance in endoscopic imaging. The usefulness and effectiveness of EUS have been established during the past few years. However, endosonography using dedicated echoendoscopes (7.5/12 MHz) has some serious drawbacks, as follows: 1) Combining endoscopy and ultrasonography in one instrument increases the diameter of such echoendoscopes (12-13 mm); 2) Because of the large diameter, complete passage of severe strictures is often not possible and, for examination of the pancreatobiliary duct system, is not feasible at all; 3) Image quality and resolution for small lesions is not always satisfactory; and 4) Conventional endosonography requires a second examination separate from the previous routine endoscopy. Recently developed ultrasonographic miniprobes (diameters about 2 mm; frequencies 12-20 MHz) can be passed through the working channel of standard endoscopes to provide high frequency ultrasound images. These miniprobes might overcome some of the above-mentioned drawbacks and contribute to patients' security and convenience. Moreover, in various diseases of the GI tract and the pancreatobiliary duct system, diagnostic accuracy of miniprobe ultrasonography has been shown to be even superior to that of EUS. In summary, miniprobe ultrasonography seems to be a promising tool in the armamentarium of gastroenterological diagnostics.

Usefulness of contrast-enhanced EUS in the diagnosis of upper GI tract diseases

BACKGROUND

We evaluated the usefulness of contrast-enhanced endoscopic ultrasonography (EUS) in the diagnosis of upper gastrointestinal (GI) tract diseases.

METHODS

The subjects were 42 patients with upper GI tract diseases: 4 esophageal carcinomas, 30 gastric carcinomas, 5 gastric myogenic tumors, and 3 gastric ulcers. After the lesion was observed by EUS, air-filled albumin (0.22 mL/kg) was intravenously injected at a rate of 1 mL/sec into the right cubital median vein, and observation was continued for 10 minutes.

RESULTS

Enhancement of the third and fifth layers was observed in all normal esophageal and gastric walls. No esophageal carcinomas were enhanced. Enhancement was observed in 5 gastric carcinomas that had abundant, enlarged, and winding vascular beds. In all esophageal and the other 25 gastric carcinomas, although the tumors per se were not enhanced, enhancement of the third and fifth layers around the lesions clearly demarcated the tumor boundaries. As a result, accuracy for detection of the depth of gastric carcinoma improved from 76.7% for EUS to 90% for contrast-enhanced EUS. All gastric myogenic tumors were enhanced, and irregularly shaped sonolucent areas within these tumors became clear, but we could not distinguish between leiomyoma and leiomyosarcoma.

CONCLUSIONS

Contrast-enhanced EUS is a noninvasive, useful diagnostic method for assessment of the depth of invasion of esophageal and gastric carcinomas.

Clinical implications of endoluminal ultrasonography using through-the-scope catheter probes

BACKGROUND

Ultrasound catheter probe-assisted endosonography is a relatively new technique. The aim of this prospective multicenter study was to determine its potential clinical impact by assessing changes in diagnostic and therapeutic management affected by catheter probes compared with ultrasound endoscopes.

METHODS

Endosonographers at three centers selected theoretic diagnostic and therapeutic plans that would be followed if neither catheter probes nor ultrasound endoscopes were available. Patients with suitable lesions underwent endosonography with catheter probes followed by an ultrasound endoscope. Diagnostic and therapeutic plans were noted after each examination.

RESULTS

Sixty-six patients, of whom 15 had a stenotic esophageal cancer, 39 had a mucosal or submucosal lesion, and 12 had a stricture of the pancreaticobiliary system or the gastrointestinal tract, were enrolled. If neither form of endosonography were available, invasive or surgical diagnostic procedures would have been performed on 23 (35%) patients and surgical therapy would have been planned in 31 (47%) patients. Catheter probe-assisted ultrasonography and endoscopic ultrasonography led to a less invasive diagnostic plan in 11 (16%) and 12 (18%) patients and a less invasive therapeutic plan in 10 (15%) and 14 (21%) patients, respectively (p > 0.1 for differences).

CONCLUSIONS

Catheter probe-assisted endosonography has a modest effect on diagnostic and therapeutic management, comparable with endoscopic ultrasonography in the same patients. The vast majority of effected changes are toward less invasive management.

Evaluation of the colorectal wall in normal subjects and patients with ulcerative colitis using an ultrasonic catheter probe

BACKGROUND

Ulcerative colitis is usually evaluated by barium enema and colonoscopy, methods of imaging that are limited to the mucosal surface. Endoscopic ultrasonography (EUS) is the best modality for the evaluation of transmural changes in the bowel wall. We therefore evaluated the colorectal wall in normal control subjects and patients with ulcerative colitis using an ultrasonic catheter probe.

METHODS

Endoscopic ultrasound with a catheter probe was performed on 36 normal control subjects (36 examinations) and 72 patients (111 examinations) with documented ulcerative colitis.

RESULTS

In normal control subjects, the total wall, mucosa, submucosa, and muscularis propria were significantly thicker in the rectum than in the colon. There was no significant difference in the thickness of the colon and rectum among different age groups or between men and women. In ulcerative colitis, we classified the boundary of each layer into three patterns (smooth, irregular, and blurred) and then classified the wall into six types. In Matts grade 2 and 3 ulcerative colitis lesions, the total wall and each layer were significantly thicker than lower grade lesions and normal control subjects. For grade 1 and most of the grade 2 lesions, the boundary of each layer was smooth. In some of the grade 3 lesions, the mucosa-submucosa and submucosa-muscularis propria layer borders were abnormal. In all grade 4 cases, the mucosa-submucosa boundary was blurred. There was some correlation between the Matts grade and EUS findings except for Matts grade 3 lesions which had various EUS patterns.

CONCLUSION

Endoscopic ultrasound with a catheter probe is a useful modality for the transmural assessment of the colorectal wall and, when used in conjunction with the many clinical and endoscopic parameters currently available, may contribute to the diagnosis and treatment of ulcerative colitis.

Pretreatment staging of endoscopically early gastric cancer with a 15 MHz ultrasound catheter probe

BACKGROUND

The usefulness of and problems associated with an ultrasound catheter probe in the pretreatment staging of endoscopically early gastric cancer remain unexplored.

METHODS

Endoscopic ultrasonography using a 15 MHz catheter probe of 2.6 mm diameter was performed in a prospective study to determine the pretherapy staging of endoscopically early gastric cancer in 78 patients. The results of the ultrasound images were compared with the histologic findings of the specimens obtained by endoscopic mucosal resection or surgical resection.

RESULTS

The accuracy of the catheter probe for depth of invasion of endoscopically early gastric cancers was 67% (52 of 78 patients). The accuracy in determining depth of invasion in relation to endoscopic type was significantly higher for the elevated type (91%) than for the depressed type of early cancer (56%) (p < 0.01). The staging accuracy classified by histologic type was significantly higher for differentiated (86%) than for undifferentiated (18%) cancer (p < 0.01). Staging accuracy decreased as tumor size increased. The accuracy, sensitivity, and specificity for nodal staging were 80%, 17%, and 90%, respectively.

CONCLUSIONS

A 15 MHz ultrasound catheter probe is most useful for determining depth of invasion when the tumor is histologically differentiated and endoscopically of the small elevated type early gastric cancer, but it is unreliable in the diagnosis of metastatic lymph nodes.

Staging of oesophageal carcinoma with high resolution endoluminal ultrasonography

Oesophageal carcinoma is a disease with poor prognosis despite improved treatment and diagnostic methods. The most important prognostic features are the degree of wall invasion and the presence of lymph node metastasis. Endoscopic ultrasonography (EUS) in the region of 7.5-12 MHz has improved the accuracy of tumour staging. In the course of 1 year, 21 patients with oesophageal carcinoma were examined with 20 MHz high-resolution intraluminal ultrasonography (HRES). In 11 (52%) patients, both ultrasound catheter and fiber gastroscope could pass the tumour, in 5 (23%) only the ultrasound catheter could pass. In the remaining patients the ultrasound catheter could only partially pass without prior dilatation. One patient was classified as having a stage T2 tumour, 14 (67%) had T3 and 4 (19%) had T4. In 2 patients the tumour could not be fully classified but was at least T3 When comparing our results with findings at computed tomography (CT), the T stage coincided in 9 patients (42%), in 9 patients (42%) CT could not differentiate between T2 and T3 and in 3 investigations HRES showed a higher T stage than CT. In 3 patients (14%) ultrasonography found N1 stage where CT staged N0. In one patient, CT found lymph nodes not seen with HRES. Further studies comparing EUS, HRES and surgical findings are planned to assess our view that HRES is a useful method in preoperative staging of oesophageal carcinoma.

Three-dimensional endoscopic ultrasonography of gastrointestinal lesions using an ultrasound probe

BACKGROUND

This study was carried out to ascertain the clinical usefulness and problems of three-dimensional (3D) images obtained with the ultrasound probe.

METHODS

Eighteen resected specimens and 21 patients were examined. After the images were recorded on video, 3D displays were produced using a workstation.

RESULTS

In the in vitro study the surface images were quite consistent with the macroscopic findings in 17 cases. In 2 esophageal cancers, 7 of 10 gastric cancers, and 2 colonic cancers the depth of tumor invasion was assessed accurately from the reconstructed images. In the in vivo study although 3 D display had some limitations, it was useful in esophageal and rectal lesions.

CONCLUSIONS

This new diagnostic method could visualize the 3D extent of gastrointestinal lesions and appears to have a useful clinical application.

Pre-operative TN staging of gastric cancer using a 15 MHz ultrasound miniprobe

The aim of the study was to evaluate the usefulness of and problems associated with a new endoscopically guided ultrasound miniprobe, used for pre-operative staging of gastric cancers. 59 cases of gastric cancer were prospectively examined with a 15 MHz ultrasound miniprobe. The results of the ultrasound imaging were compared with the histological findings of the resected specimens. The accuracy of the miniprobe for depth of invasion (T category) was 61% for all tumours, and 72% and 40%, respectively, for T1 and T2 to T4 lesions. If indeterminate cases due to ultrasound attenuation were excluded, the accuracy was improved to 82% for T1 and 57% for T2 to T4 tumours, respectively. The accuracy of the miniprobe for nodal staging (N category) was 69% overall, and 86%, 25% and 14% for stages N0, N1 and N2, respectively. In tumours classified on the basis of endoscopic types, the miniprobe staged early type gastric cancers (T category = 73%, N category = 80%) significantly (p < 0.01) more accurately than advanced ones (T category = 21%, N category = 36%). This study suggests that the miniprobe is indicated for pre-operative TN staging when endoscopy reveals an early gastric cancer.

Transendoscopic ultrasonography during conventional upper gastrointestinal endoscopy. Clinical evaluation of a linear 20-MHz probe system

BACKGROUND

Endoluminal ultrasonography provides detailed images of the gastrointestinal wall and surrounding tissue. Miniature ultrasound probes can be applied during conventional endoscopy.

METHODS

The supplementary diagnostic information obtained during endoscopy with a linear 20-MHz ultrasound probe system was independently assessed by two observers applying a general rating system on 188 consecutive examinations in 173 patients.

RESULTS

On average, 70% of the examinations were found to contribute conclusive or important supplementary information that could potentially influence treatment or further patient evaluation (substantial diagnostic yield). Substantial diagnostic yield was most often obtained in patients with known malignancy (92%), stenoses (81%), or subepithelial masses (80%) and more often in patients with malignant (85%) than in those with benign (61%) conditions (P < 0.001).

CONCLUSIONS

Transendoscopic ultrasonography using a 20-MHz linear miniature ultrasound probe may provide substantial supplementary diagnostic information during upper gastrointestinal endoscopy, especially in patients with malignant disease and with stenotic or subepithelial lesions.

Endoscopic ultrasonography of superficial esophageal cancers using a thin ultrasound probe system equipped with switchable radial and linear scanning modes

BACKGROUND

Detailed information on the depth of invasion of superficial esophageal cancer is required for endoscopic mucosal resection. As a pretherapeutic diagnostic procedure, endoscopic ultrasonography using conventional 7.5 MHz systems has been ineffective at providing sufficient details. A newly developed, thin ultrasound probe system provides both radial and linear scanning for evaluation of superficial esophageal cancer.

METHODS

Endoscopic ultrasonography was performed in 16 patients using a switchable probe driven at 20 MHz. Seventeen lesions of superficial esophageal cancer were evaluated for depth of invasion to discriminate mucosal from submucosal penetration.

RESULTS

The overall accuracy of staging was 64.7%. In all six errors, mucosal cancers were overstaged as submucosal invasion. The diagnostic accuracy was 80% when the muscularis mucosae was visualized.

CONCLUSION

A 20 MHz linear-radial switchable probe is a useful new method in the staging of superficial esophageal cancer.

Preoperative staging of superficial esophageal carcinoma: comparison of an ultrasound probe and standard endoscopic ultrasonography

BACKGROUND

In diagnosing superficial esophageal carcinoma, it is necessary to differentiate mucosal carcinoma from submucosal carcinoma because mucosal carcinoma has a good prognosis and local treatment is likely to be successful. We evaluated an ultrasound probe and endoscopic ultrasonography (EUS) in the staging of superficial esophageal carcinoma.

METHODS

From October 1992 to September 1994, 22 patients with 25 lesions (7 mucosal carcinomas, 18 submucosal carcinomas) were examined preoperatively with both the probe and EUS. The ultrasound findings were compared with histologic findings in all cases.

RESULTS

The accuracy rates of the depth of invasion by the ultrasound probe were 86% (6 to 7) for mucosal carcinoma and 94% (17 to 18) for submucosal carcinoma, total 92% (23 to 25); by EUS 71% (5 to 7) for mucosal carcinoma and 78% (14 to 18) for submucosal carcinoma, total 76% (19 to 25). In the evaluation of lymph node metastasis, the overall accuracy was 56% by the ultrasound probe (sensitivity 25% and specificity 80%) and 67% by EUS (sensitivity 50% and specificity 80%).

CONCLUSIONS

The ultrasound probe was more convenient to use and more accurate than EUS in the evaluation of the depth of invasion of superficial esophageal carcinoma.

Ultrasonography of the human stomach

Improved technology and new systems have expanded the possibilities of using ultrasound in clinical gastroenterology.

METHODS

Conventional real-time ultrasound was applied to the stomach in order to study motor activity and accommodation to meals. The antrum was imaged by various modalities of two- and three-dimensional ultrasonography, while duplex sonography was used for studying transpyloric flow. Miniature ultrasound probes and echo-endoscopes were employed for endoscopic ultrasound

RESULTS

The examinations provided new information about contractions, distension, co-ordination of movements, and flow. Patients with functional dyspepsia were characterized by rapid emptying of the proximal stomach, wide gastric antrum, early commencement of transpyloric flow, and epigastric discomfort following ingestion of a meat soup. Endoscopic ultrasonography exposed detailed images of the gastric wall and adjacent structures of great importance in clinical decision-making.

CONCLUSIONS

The new ultrasound methods have improved our diagnostic capabilities and opened new promising possibilities for further research in the field of motility.

Ultrasonic esophagoprobe for TNM staging of highly stenosing esophageal carcinoma

BACKGROUND

Endosonographic staging of esophageal carcinoma may be limited in one third of cases by tumor stenoses that cannot be traversed with conventional echoendoscopes. We designed and evaluated a new endosonographic instrument (ultrasonic esophagoprobe) for TNM staging of highly stenosing esophageal carcinomas.

METHODS

Eighty-seven consecutive patients (64 men, mean age 61 years) with highly stenosing esophageal carcinomas were studied with the esophagoprobe (features: diameter of 7.9 mm, bougie-shaped tip, no fiber optics, insertion over a guide wire).

RESULTS

The esophagoprobe was successfully inserted past the stenosis without complication in all patients. Nine patients (10%) required preliminary bougienage to 33 F. The imaging quality was high and allowed for complete T and N staging in all patients. M staging was indeterminate in 15 patients because of inadequate visualization of the celiac axis region. Histopathologic correlation in 38 patients who underwent surgery showed an overall T stage accuracy rate of 89% (T2 = 80%, T3 = 95%, T4 = 87%), and N and M stage accuracies of 79% (N0 = 44%, N1 = 90%) and 91% (M0 = 94%, M1 = 75%), respectively.

CONCLUSIONS

The esophagoprobe enables safe passage of highly stenosing esophageal carcinomas for TNM staging. Accuracy rates are similar to those reported for conventional echoendoscopes.

Endoscopic assessment of invasion of colorectal tumors with a new high-frequency ultrasound probe

The present study was carried out to clarify the usefulness of and problems associated with a new ultrasound probe in the assessment of invasion of colorectal tumors. Normal colorectal wall of 23 resected specimens from colorectal cancer cases was examined in vitro with the probe. Fifty-one patients with colorectal carcinoma and 16 patients with rectal carcinoid tumor were presurgically examined using the probe via the biopsy channel of a conventional colonoscope. After endoscopic and ultrasonographic examination, 27 patients underwent endoscopic resection and 40 underwent surgical resection. The ultrasonographic findings were compared with histologic findings in all cases. Carcinomas and carcinoid tumors were visualized as an echo-poor region with the probe. The overall accuracy rate for depth of invasion was 76% (39/51) for colorectal cancer. The accuracy rates for tumors limited to the mucosa and tumors invading the submucosa were 83% and 90%, respectively; these rates were higher than those for tumors invading the muscularis propria (50%) and beyond the muscularis propria (73%). In all 16 cases of carcinoid tumor, the depth of invasion was accurately shown to be limited to the submucosa. This probe is useful to assess invasion of colorectal tumors, especially small and flat lesions limited to the mucosa or submucosa.