Evaluation and biopsy of recurrent rectal cancer using three-dimensional endosonography

Biplane mode for more precise intrauterine procedures

The evolution of ultrasound and the introduction of 3- and 4-dimensional ultrasound techniques led to a shift in the perception and usage of ultrasound in fetal medicine. The biplane mode might help in multiple fetal procedures, including but not limited to basic intrauterine thoracocentesis, thoracoamniotic shunting, amnioreduction, amnioinfusion, cordocentesis, intraumbilical infusion, and umbilical cord coagulation, with a possible reduction in the complication rate. Despite its theoretical usefulness, more studies are required to assess the clinical importance of this technique.

Secondary linitis plastica of the rectum: EUS features and tissue diagnosis (with video)

BACKGROUND

Luminal metastases to the GI tract may be seen at the time of the primary diagnosis or may represent evidence of a distant recurrence.

OBJECTIVES

To determine the prevalence of rectal-wall metastases in patients undergoing an EUS and to describe the EUS features and yield of EUS-guided FNA (EUS-FNA) and Trucut biopsy (TCB).

DESIGN

A case series.

SETTING

A single tertiary-referral center.

PATIENTS

Patients undergoing lower GI (LGI) EUS from July 1, 2005, to October 31, 2007.

INTERVENTION

EUS-FNA and/or TCB.

MAIN OUTCOME MEASUREMENTS

EUS features and cytologic and/or histologic confirmation of secondary rectal linitis plastica.

RESULTS

Over the 28-month period, an LGI-EUS was performed in 598 patients with presumed primary rectal cancer, of whom 6 (1%) were diagnosed with rectal-wall metastases. The EUS features were that of diffuse, circumferential, hypoechoic wall-thickening that mimics that of linitis plastica, breaching the muscularis propria in all cases. EUS-FNA and/or TCB of the rectal wall or perirectal lymph node established a diagnosis in all cases. The primary cancers originated from the bladder (n = 3), breast (n = 1), stomach (n = 1), and a right forearm cutaneous melanoma (n = 1). The time interval from the initial primary cancer diagnosis to that of GI-tract rectal metastasis ranged from 0 days (simultaneous diagnoses) to 119 months (mean +/- SD 49 +/- 43 months).

LIMITATIONS

Although firm EUS criteria of rectal-wall metastases cannot be established based on 6 patients alone, certain features may prove useful for the diagnosis in the clinical practice.

CONCLUSIONS

EUS-FNA and/or TCB can confirm the diagnosis of secondary linitis plastica of the rectum.

The role of three-dimensional endoluminal ultrasound imaging in the evaluation of anorectal diseases: a review

BACKGROUND

The authors conducted a review of the available English literature to evaluate the advantages of three-dimensional ultrasound for assessing anorectal pathology, to provide a state-of-the-art approach, and to compare this technique with conventional endoluminal ultrasound and other imaging methods.

METHODS

All studies describing results obtained with three-dimensional ultrasound in the evaluation of anorectal pathologies, both alone and compared with other techniques, were selected.

RESULTS

Since 1996, 32 articles have been published. In tumor staging, specific data derived by three-dimensional reconstruction for the assessment of T invasion and nodal involvement were more accurate than endoluminal ultrasound and computed tomography. For evaluating perianal sepsis, the detection of secondary fistula tracts and fluid collections and the location of internal openings were superior to endoanal magnetic resonance imaging. In the evaluation of anal incontinence, the results for sphincter defects were similar to those obtained with endoanal magnetic resonance imaging.

CONCLUSION

Analysis of the literature confirmed that three-dimensional ultrasound is a valuable technique for assessing anorectal disorders, facilitating the interpretation of the images obtained, and providing additional data that in many cases have changed the operative approach.

Anorectal ultrasound for neoplastic and inflammatory lesions

Accurate staging of rectal and anal carcinoma is crucial for planning surgery and indicating adjuvant therapy. Although, computed tomography and magnetic resonance imaging are very sensitive in detecting metastatic disease, the local staging of rectal cancer with these techniques has been disappointing. Endorectal ultrasound (ERUS) and anal endosonography (AE) remain the most accurate methods for staging rectal and anal cancer. Anal endosonography is also of value in evaluating perianal sepsis: it can assist the surgeon in planning the surgical strategy by delineating the anatomy of fistula tracts, and can aid in puncturing abscesses in the operating room. Continued research and development has made the instrumentation for ERUS and AE more accurate and user-friendly. New techniques that have contributed significantly to the evolution of ERUS include three-dimensional ERUS, high-frequency miniprobes, transrectal ultrasound-guided biopsy techniques and hydrogen peroxide-enhanced endosonography. Further improvements can be expected from contrast enhancement with microbubbles and colour Doppler imaging. In this new millennium, new developments in ERUS and anal endosonography, such as tri-dimensional ERUS and anal endosonography and radial electronic probing, widen the role of ERUS in the staging of rectal and anal carcinoma, as well as for perianal inflammatory conditions.

Four-dimensional ultrasonographic guidance for invasive obstetric procedures

OBJECTIVE

This pilot study evaluated the use of 4-dimensional (4D) real-time ultrasonographic needle guidance for amniocentesis, chorionic villus sampling (CVS), cordocentesis, and intrauterine transfusions.

METHODS

Ninety-nine consecutive procedures were performed with 4D (real-time) multiplanar ultrasonographic imaging. Amniocentesis was done freehand in 3 orthogonal planes of view. Chorionic villus sampling, cordocentesis, and intrauterine transfusions were accomplished with a needle guide and 2 projected orthogonal planes.

RESULTS

Needle tip visualization in the A, B, and C orthogonal planes during amniocentesis was noted in 93%, 63%, and 69% of cases, respectively. When a needle guide was used during CVS and cordocentesis, the needle tip was always seen in the 2 projected orthogonal planes, and no lateralization occurred. Four intrauterine transfusions were done with the 4D technique. The only procedural complication in any patient was bradycardia from vessel spasm during an intrauterine transfusion, requiring a cesarean delivery. There were no statistical differences (P > .05) between the numbers of needle insertions required in the 4D group compared with a historical control group in which 2-dimensional ultrasonographic needle guidance was used.

CONCLUSIONS

In this feasibility study, a real-time 4D needle guidance technique was successfully used to perform amniocentesis, CVS, cordocentesis, and intrauterine transfusion. This appeared to contribute to the accuracy of needle placement by eliminating the lateralization phenomenon when a fixed needle guide attachment was used (for CVS and cordocentesis). Needle tip visualization was seen in each orthogonal plane in most freehand 4D amniocentesis cases. Future developments in 4D ultrasonographic technology may refine the utility of this technique for invasive obstetric procedures.

EUS-FNA of recurrent postoperative extraluminal and metastatic malignancy

BACKGROUND

EUS-guided FNA is safe and accurate for the diagnosis of benign or malignant neoplasia and lymphadenopathy; however, its role in the diagnosis of recurrent malignancy is not well described.

METHODS

A prospectively updated EUS-guided FNA cytology database was used to identify patients in whom a diagnosis of postoperative, recurrent, extraluminal, or metastatic malignancy was made over a 5-year period. Only patients with a positive EUS-guided FNA were included in the analysis. All had undergone surgery for the primary malignancy and were in clinical and/or radiographic remission before the initial suspicion of tumor recurrence.

RESULTS

Twenty-one patients underwent EUS-guided FNA of 21 lesions (19 masses, 2 lymph nodes) because of a suspicion of recurrent malignancy based on CT (n = 17) or EUS (n = 4) findings. Median time from the initial diagnosis to recurrence was 26 months (range 5-276 months). Lesions were located in the pancreas (9 patients), mediastinum (7), liver (3), perigastric region (1), and liver hilum (1). EUS-guided FNA (mean number of needle passes, 4.5; range 2-8) obtained diagnostic material for recurrent malignancy in all patients as follows: esophageal (6 patients), renal cell (6), pancreatic (2), breast (2), colon (2), bile duct (1), Ewing's sarcoma (1), and lung (1) cancer. No complication was encountered. Transgastric EUS-guided FNA (4 patients), distal, or transesophageal EUS-FNA (2) proximal to a surgical anastomosis was required to confirm recurrence in all 6 patients with esophageal cancer. The initial cytologic diagnosis of recurrent malignancy was made by EUS in 20 of 21 (95%) patients. One patient with recurrent breast cancer had CT-guided FNA of a right lung mass preceding EUS-guided FNA of an AP window lymph node.

CONCLUSIONS

EUS-guided FNA can detect and safely diagnose recurrent malignancy in the mediastinum, retroperitoneum, and liver. When possible, correlation between EUS-guided FNA cytology and original tumor histopathology/cytology, or the use of immunostaining to confirm the diagnosis, is recommended.

Comparative study of three-dimensional and conventional endorectal ultrasonography used in rectal cancer staging

BACKGROUND

Three-dimensional (3D) imaging offers improved knowledge of various anatomic structures and tumors by providing 3D images. This prospective study was performed to verify whether 3D endorectal ultrasonography (EUS) enhances the accuracy of rectal cancer staging, as compared with conventional EUS.

METHODS

Using both 3D and conventional EUS, 33 consecutive patients with operable rectal cancer were preoperatively staged. A rigid 3D probe with a scanner was used for 3D EUS, and a rigid endorectal probe with a scanner was used for conventional EUS.

RESULTS

The accuracy of 3D EUS was 90.9% for pT2 and 84.8% for pT3, whereas that of conventional EUS was 84.8% and 75.8%, respectively, thereby showing no difference between these two methods. The lymph node metastasis was accurately predicted by 3D EUS in 28 patients (84.8%), whereas conventional EUS predicted the disorder in 22 patients (66.7%). The difference was not statistically significant. The average infiltration grade of the circumference on transverse 3D EUS scans was associated closely with advancement of the TNM stage (p <0.001-0.006) and lymph node metastasis (p = 0.003). The presence of a cone-shaped surface on the deep tumor border correlated with the infiltration grade shown on all of the sectional displays (p <0.001-0.042) and with advancement of the TNM stage (p = 0.018).

CONCLUSIONS

Although the findings did not show 3D EUS to have a significant advantage over conventional EUS for the accurate evaluation of rectal cancer, a numeric advantage may possibly be statistically significant in a further study with larger cases. Furthermore, stereoscopic visualization provided easier and complete understanding of both focal lesions and lymph nodes.

Endoscopic ultrasound and endoscopic mucosal resection for rectal cancers and villous adenomas

EUS is the most accurate tool for local staging of rectal carcinoma. In addition to providing accurate T- and N-stages, EUS allows assessment of the internal and external anal sphincters. Accurate endosonographic staging directs the optimal method of management of rectal carcinoma, type of resection, and candidacy for neoadjuvant therapy. EMR may be applied to large rectal adenomas as an alternative to surgical resection in selected patients. EUS is important in discriminating lesions suitable for EMR.

The role of transrectal ultrasound-guided biopsy in the postoperative follow-up of patients with rectal cancer

BACKGROUND

The value of endorectal ultrasound (EUS) in the diagnosis of recurrent rectal cancer is limited by the inability to differentiate between malignant and benign lesions. We have prospectively investigated the role of EUS with transrectal ultrasound-guided biopsy in the postoperative follow-up of rectal cancer.

METHODS

Since 1995, patients who had undergone a sphincter-saving operation for rectal cancer (n = 312) were followed-up by a standard program including rectal palpation, carcinoembryonic antigen monitoring, computed tomography, and EUS. Transrectal EUS-guided biopsy of perirectal lesions was performed in 68 patients with perirectal lesions by using a rigid endoprobe with a 10 MHZ multiplane transducer and special targeting device.

RESULTS

Overall local recurrence was observed in 36 patients. Intraluminal recurrence was diagnosed by proctoscopy in 12 patients. Transrectal EUS-guided biopsy showed pelvic recurrence in 22 of 68 patients with perirectal lesions. Biopsy specimens with benign histology were obtained from 41 patients, and the procedure failed in 5 cases (accuracy, 92%). There was a strong agreement between transrectal biopsy results and the final diagnosis (kappa = 0.84), the sensitivity and specificity being 91% and 93%, respectively. In contrast, clinical examination (kappa = 0.27), computed tomography (kappa = 0.47), or EUS (kappa = 0.42) showed only a moderate level of agreement with the histopathologic diagnosis, mainly because of the limited specificity of all 3 methods (65% vs 46% vs 57%). EUS-guided biopsy was significantly more accurate than computed tomography and EUS (P <.01). The biopsy results had a considerable impact on the management in 18 of 68 patients (26%).

CONCLUSIONS

Transrectal EUS-guided biopsy is a safe and efficient method for tissue sampling of perirectal lesions. This minimally invasive and inexpensive technique improves the accuracy of endorectal ultrasound in the diagnosis of recurrent rectal cancer.

Ultrasound imaging in three and four dimensions

Three-dimensional (3D) reconstruction of ultrasound images was first demonstrated nearly 15 years ago, but only now is becoming a clinical reality. In the meantime, methods for 3D reconstruction of CT and MRI images have achieved an advanced state of development, and 3D imaging with these modalities has been applied widely in clinical practice. 3D applications in ultrasound have lagged behind CT and MRI, because ultrasound data is much more difficult to render in 3D, for a variety of technical reasons, than either CT or MRI data. Only in the past few years has the computing power of ultrasound equipment reached a level adequate enough for the complex signal processing tasks needed to render ultrasound data in three dimensions. At this point in time, the clinical application of 3D ultrasound is likely to advance rapidly, as improved 3D rendering technology becomes more widely available. This article is a review of the present status of 3D ultrasound imaging. It begins by comparing the characteristics of CT, MRI, and ultrasound image data that either make these data amenable or not amenable to 3D reconstruction. The article then considers the technical features involved with acquiring an ultrasound 3D data set and the mechanisms for reconstructing the images. Finally, the article reviews the literature that is available regarding clinical application of 3D ultrasound in obstetrics, ultrasound, the abdomen, and blood vessels.

3D-endosonography in gastroenterology: methodology and clinical applications

Endoluminal ultrasonography allows detailed imaging of the gastrointestinal wall and adjacent structures. Three-dimensional (3D) imaging may improve visualisation of topographic relations and the nature of pathologic lesions. The objective of this report is to summarise current status of 3D-endosonography and to discuss the possible clinical impact of this new modality. 3D ultrasonographic images are usually generated from a series of digitised two-dimensional ultrasound pictures acquired in a manner that enables registration of their relative spatial position. Such acquisition can be accomplished with different ultrasound probes, but in most cases of endosonography, a controlled pullback of radial-scanning probes has been applied. Digital ultrasound images are obtained by frame grabbing of analogue video recordings or by direct transmission from digital scanners. Dedicated software programs have been developed for 3D reconstruction and visualisation, allowing interactive display and measurements. 3D endosonography provides new possibilities for clinical imaging, but the impact on therapeutic strategies and clinical outcome has yet to be established.

Multidisciplinary management of recurrent colorectal cancer

Isolated pelvic recurrence of rectal carcinoma may occur in up to one third of patients following definitive resection of primary disease. The means by which recurrence is diagnosed, methods by which it may be treated, and reported outcomes are all evolving and improving. Current data indicate that a substantial proportion of patients treated by aggressive multi-modality salvage therapy may be provided with durable survival. This review highlights current concepts in the diagnosis and management of locally recurrent rectal carcinoma.

The latest in ultrasound: three-dimensional imaging. Part II

INTRODUCTION

The three-dimensional (3D) reconstruction of ultrasound images has become a widespread option in ultrasound equipment. Specific softwares have become available and 3D reconstruction feasible since the early 1990s, particularly since 1994.

POSSIBLE CLINICAL APPLICATIONS

Several clinical applications are feasible in all parenchymatous organs (mainly the liver and prostate), hollow viscera (e.g. the bladder and gallbladder), peripheral vessels (supra-aortic trunks and limb vessels) and central (the aorta and iliac arteries) or cerebral vessels. Moreover, tumoral vessels in parenchymatous organs can be reconstructed, and even the fetus in the uterine cavity, with excellent detailing. The recent introduction of echocontrast agents and second harmonic imaging has permitted to study normal and abnormal peripheral, central and parenchymatous vessels, with similar patterns to those obtained with digital angiography. The spatial relationships between the vascular structures of the liver, kidney and placenta were studied with 3D ultrasound angiograms. The applications of this new technique include the analysis of vascular anatomy and the potential assessment of organ perfusion. THE LATEST APPLICATIONS--INTRAVASCULAR STUDIES: Some catheters with an ultrasound transducer in the tip have been tested for intravascular studies. Just like conventional transducers, they provide two-dimensional (2D) images which are then postprocessed into longitudinal 3D or volume reconstructions. The former resemble angiographic images and can be viewed 3D rotating the image along its longitudinal axis. Volume images, which are more complex and slower to obtain, can be rotated on any spatial plane and provide rich detailing of the internal vascular lumen. The clinical importance of intravascular ultrasound with 3D volume reconstructions lies in the diagnosis of vascular conditions and the assessment and monitoring of intravascular interventional procedures--e.g. to detect inaccurate deployment of intravascular stents and endoluminal grafts during the maneuver. Three-dimensional reconstructions involve geometric data assembly and volumetric interpolation of a spatially related sequence of tomographic cross sections generated by an ultrasound catheter withdrawn at a constant rate through a vascular segment of interest, resulting in the display of a straight segment. Therefore particular care is needed and there are some useful hints to avoid mistakes.

CONCLUSIONS

Three dimensional reconstructions of B-mode and color Doppler images are no longer a work in progress and their clinical importance and possible applications are both established and ever-increasing. On the other hand, independent of the different types of energy used, also computed tomography and magnetic resonance 3D reconstructions are very useful from a clinical viewpoint and they have become an established routine technique for both these methods. It is very likely that 3D volume reconstructions in ultrasound will find numerous applications in the near future. They may help to increase the diagnostic confidence and to facilitate diagnosis, intraprocedure monitoring in interventional radiology and follow-up and also to reduce the number of invasive examinations with iodinated contrast agents. This could result in cutting the cost and duration of the most expensive examinations. New, although invasive, applications can be hypothesized for intravascular or intraluminal catheters with an ultrasound transducer inside.

The latest in ultrasound: three-dimensional imaging. Part 1

OBJECTIVE

The state-of-the-art of three-dimensional ultrasound is reviewed to evaluate technological achievements and future possibilities in diagnosis and in the follow-up of medical or invasive therapy.

MATERIAL AND METHODS

The problems related to volumetric acquisitions in the tissues of interest to provide three-dimensional images are considered. Three-dimensional images are easier to achieve with computed tomography because the scanning system of this technique is automatic and thus provides sequential slices. The same is true for magnetic resonance imaging which can aquire volumes directly. The problem with ultrasound lies in the fact that the scans are manual and therefore less precise. To obtain three-dimensional images these devices are commonly used: manual scanning probes connected to spatial magnetic evidencers with remote processing; manual scanning probes connected to spatial magnetic evidencers placed on the patient's examination table with processing internal to the ultrasound unit; mechanical probes that can provide volumetric scans; 'matrix' probes. Recent contributions are discussed relative to three-dimensional applications to cardiology (cardiac valve studies), obstetrics (malformations), gynecology (uterine malformations and extensive ovarian disease studies), gastroenterology (diagnosis of pancreatic and hepatoabiliary tumor extent), uro-nephrology (detection of stones, prostatic tumors) and finally in the study of rectal carcinomas.

CONCLUSIONS

Nearly all the papers about three-dimensional ultrasound are works in progress because the technique has not been standardized yet and some of its future diagnostic possiblities are difficult to foresee. Moreover, 'matrix' probes are still in the experimental stage. Nevertheless, this technique seems to be able to yield the best results in: fetal malformations; calculating the volumes of normal and diseased organs; the follow-up of masses treated with irradiation/chemotherapy or with alcohol or chemoembolization; the spatial reconstruction of extensive lesions; the detection of small lesions (metastases); the study of some complex functions such as cardiac valve dynamics. But the real problem with three-dimensional sonography is not its efficiency but rather its efficacy, that is which actual role this technique can play in diagnosis and which information it can add to that obtained with two-dimensional imaging.

Analysis of linear, area and volume distortion in 3D ultrasound imaging

We have developed a three-dimensional (3D) ultrasound imaging system that uses a side-firing probe, axially rotated under computer control, to acquire a series of 2D images, from which the 3D image is reconstructed. For an undistorted reconstruction, the inner radius R0 of the 2D images and the total scanning angle theta must be known accurately. Here, we describe (a) a theoretical analysis of the relative distortion in image shape, length, area, and volume due to an error delta R in R0 or delta theta in theta; (b) measurements of these in simulated and real 3D images; and (c) a method to calibrate R0, theta, and image scale accurately. Theoretically, all four relative distortions vary as P delta R/R + Q delta theta/theta, where magnitude of P < or = 1, magnitude of Q < or = 1, and R is the average distance of the object from the axis. In every case, the simple theoretical formulas for P and Q agree with image measurements to within the measurement uncertainty.