Efficacy of High Resolution Transabdominal Sonography of the Fluid Filled Stomach in the Evaluation of Gastric Carcinomas

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1 Efficacy of High Resolution Transabdominal Sonography of the Fluid Filled Stomach in the Evaluation of Gastric Carcinomas S SINGH, V CHOWDHURY ABSTRACT AIM: To evaluate the efficacy of high-resolution transabdominal sonography of the fluid filled stomach in the evaluation of gastric carcinomas. Materials and Methods:- Fifty one patients with a clinical diagnosis of gastric disease were included in the study. The patients were taken for conventional abdominal sonography followed by high resolution transabdominal sonography of the fluid filled stomach. An UGI endoscopy was done in all 51 cases and biopsy taken from pathological / suspicious site. The accuracy of high resolution sonography of the fluid filled stomach was evaluated in the diagnosis of gastric carcinoma as compared to endoscopy. Results:- High resolution sonography diagnosed all 17 cases of gastric carcinoma while endoscopy failed to diagnose one case of scirrhous carcinoma. Sonography underestimated the intraluminal extent in two cases while endoscopy underestimated the extent in three cases. Sonography provided an estimate of the exogastric extent in the majority of the cases not available by endoscopy. However endoscopy has the advantage of direct biopsy being taken and histopathological correlation was obtained. Conclusion:- High resolution sonography is a supportive diagnostic modality and is a supplementary diagnostic procedure to endoscopy. Ind J Radiol Imag :4: Keywords: Gastric, carcinoma, High resolution ultrasound, fluid filled stomach. INTRODUCTION It has recently been shown that dedicated transabdominal ultrasound performed after ingestion of water and injection of a hypotonic agent along with the use of high frequency transducers provides detailed and unique evaluation of the stomach. Ultrasound is often used as the first imaging modality in a large variety of abdominal complaints and clinically unsuspected gastric carcinomas may be imaged first by it. MATERIAL AND METHODS:- A total of 51 patients with a clinical diagnosis of gastric disease were included in the study. Detailed clinical history and relevant points in clinical examination and relevant investigations were carried out. The patients were then subjected to conventional abdominal sonography followed by high resolution sonography of the fluid filled stomach. An UGI endoscopy was done on all 51 cases. Any abnormality detected was noted and biopsy taken from pathological or suspicious site. In patients who underwent surgery operative findings were noted and histopathological correlation obtained wherever possible. Ultrasound examination was performed using a real time ultrasound with 3 MHz, 5 MHz and/or 7.5 transducers as required. Patients were taken up for examination empty stomach after overnight fasting and in cases of gastric outlet obstruction after Ryle's tube aspiration. The From the Department of Radiodiagnosis, Maulana Azad Medical College and Associated Lok Nayak Hospital, New Delhi, Jawahar Lal Nehru Marg, New Delhi Request for Reprints: Dr. Sapna Singh, 212, SFS Flats, Phase IV, Ashok Vihar, Delhi Received 19 April 2005; Accepted 10 October 2005

2 S Singh et al IJRI, 15:4, November 2005 patients were given 500 ml to a maximum of 1000 ml of tap water to drink. At the same time, 20mg Hyoscine N/ butyl bromide (Buscopan) was injected intravenously to achieve optimal distension and to suppress gastric peristalsis. Scanning was done in longitudinal, transverse and left sided subcostal oblique positions. The aim of the procedure was to remove air from the segment of the stomach under investigation by appropriate positioning. The normal stomach was identified using the following criteria:- 1. Good distensibility of the stomach in all sections with a uniform wall thickness of upto 4mm to 5mm. In the distal antrum this figure is exceeded by 2-3 mm. gastro-oesophageal junction with involvement of fundus was seen in four (23.5%) cases, the body was involved in three cases and diffuse involvement of the stomach was seen in one case (Table 1). TABLE 1 Site of Involvement in Gastric Carcinoma by Sonography (n=17). Site No. of Patients Percentage 1. Gastro oesophageal junction with % involvement of fundus. 2. Body % 3. Antrum % 4. Diffuse involvement % 2. Uninterrupted layering of the wall. 3. Identification of the five layers in the gastric wall. From the inside to the outside a hyperechoic layer is followed by alternating hypoechoic and hyperechoic layers (Figure 1). Layers 1 and 2 adjacent to the lumen represent the mucosa. Layer 3 which is hyperechoic represents the submucosa. Layer 4 which is hypoechoic represents the muscularis propria. Layer 5 which is hyperechoic corresponds to the serosa and subserosal fat. 4. Identification of continuous peristalsis when the effect of Buscopan wear off. The diagnosis of gastric lesions was based on:- i) Wall thickness more than 5mm, in the distal antrum more than 8 mm. ii) Loss of normal wall stratification. iii) Circumscribed widening of the individual layers. Iv) Luminal narrowing v) Absent or reduced persistalsis. vi) Considerable paucity of echoes in the wall. vii) Abnormalities of the surrounding connective tissues. RESULTS:- Seventeen patients of gastric carcinoma were present in the study. The age range was between years with highest number of patients in the age group years. There were eleven men (64.79%) and six women (35.29%). The commonest symptoms with which patients of gastric carcinoma presented were weight loss (76.4%) and abdominal pain (70.5%). This represented the advance stage of the disease at which most of our patients present. The commonest site of gastric involvement in carcinoma was the antrum - nine out of 17 cases (52.94%). The TABLE 2 High Resolution Sonography:- Findings in patients of Gastric Carcinoma (n=17) Characteristics Gastric CarcinomaPercentage (n=17) 1. Wall layering: a) Preserved 0 0% b) Partially lost 0 0% c) Lost completely % 2. Wall thickness:- b) Increased % 3. Wall echotexture:- b) Hypoechoic % c) Hyperechoic 0 0% 4. Lumen:- b) Narrow % 5. Peristalsis: b) Reduced/absent % 6. Intraluminal mass/polypoidal projection. a) Present % b) Absent % 7. Serosal involvement:- a) Intact % b) Breach %

3 423 IJRI, 15:4, November 2005 Efficacy of High Resolution Transabdominal Sonography 423 the cases (100%). Patients with gastric carcinoma had a wall thickness ranging from 10mm to 32.4mm with an average wall thickness of 22.5 mm. There was luminal narrowing and reduced peristalsis seen in all the 17 cases. Heterogeneous intraluminal masses were seen in 14 out of 17 (82.35%) cases of gastric carcinoma (Fig. 2a, 2b). Serosal involvement was seen in 13 out of 17 (76.47%) cases (Table 2). Figure 1. Sonogram of the fluid filled stomach showing normal five layers of the gastric wall. From the luminal side the layers are - layers 1 and 2 - mucosa, layer 3 - submucosa, layer 4 - muscularis externa, layer 5 - serosa. Para-aortic lymph nodes were seen in four patients (Fig. 3) and hepatic metastases was detected in all the three patients (Table 3). Sonography failed to detect involvement of transverse mesocolon seen at operation in two patients. Involvement of the gastrohepatic and gastrocolic ligament seen at operation in one patient was not seen preoperatively on sonography. TABLE 3 Sonography:- Exogastric extent & distant spread of gastric carcinoma as shown by sonography (n=17) Exogastric extent & distant No. of Patients Spread 1. Liver 3 2. Para aortic LN 4 3. Free fluid 6 4. Invasion of the pancreas 3 5. Involvement of the transverse mesocolon - 6. Involvement of the gastrohepatic & gastrocolic ligament - Figure 3. Conventional abdominal sonography showing pre and para-aortic lymphadenopathy. Figure 2a. Ultrasound of the fluid filled stomach showing a mass in the body with exogastric extent - Carcinoma body. Figure 2b. Barium meal UGI of the same patient showing a mass in the body with mucosal destruction - Carcinoma body. In all 17 patients of gastric carcinoma (100%) wall layering was completely lost. Wall thickness was increased in all DISCUSSION:- The most common site of involvement was the antrum nine out of 17 cases (52.9%). Our findings are in agreement with the well-established fact that carcinoma stomach most commonly involves the antrum [1].

4 S Singh et al IJRI, 15:4, November 2005 Figure 4. Transverse and longitudinal scans of the fluid filled stomach showing a heterogeneous mass in the antrum with complete disruption of wall layering in the region of the mass. Figure 6a. Sonogram of the fluid filled stomach showing an intraluminal mass with disruption of wall layering - carcinoma antrum. Figure 6b. Barium meal UGI of the same patient showing abrupt narrowing and shouldering in the antrum - Carcinoma antrum. All patients of gastric carcinoma showed a complete loss of wall stratification (Fig. 4). The wall echotexture was hypoechoic with heterogeneous areas in the majority of cases. Luminal narrowing and reduced peristalsis was observed in all the 17 cases (100%) (Fig. 5a, 5b). There was increase in wall thickness in all cases ranging from 10 mm to 32.4 mm with an average wall thickness of 22.5 mm. Heterogeneous intraluminal masses were seen in 14 out of 17 cases (82.35%) (Fig. 6a, 6b). Figure 5a Ultrasound showing gross hypoechoic wall thickening with luminal narrowing in the region of the body. Serosa appears intact-carcinoma body. Figure 5b. Barium UGI of the same patient showing decreased distensibility of the body with mucosal ulcerations. Our findings are in concordance with that of Yeh and Rabinowitz [2] who stated that ultrasonographic features of gastric tumours can be divided into three main categories:- a) thickened gastric wall due to infiltration by tumour. b) A mass c) A combination of two The sonographic features seen were also in agreement with that of Worlieck et al [3] who stated that a localized

5 425 IJRI, 15:4, November 2005 Efficacy of High Resolution Transabdominal Sonography 425 carcinoma may be seen as a hypoechoic or moderately echoic circumscribed wall thickening with irregular contours and interrupted wall layering and a scirrhous carcinoma may be visualized as an extensive predominantly hypoechoic mural infiltration, partly uniform partly irregular or polypoid thickening of the wall; a lack of distensibility of the stomach wall with narrowing of the lumen or stenosis. Figure 9. Sonogram of the fluid filled stomach showing a heterogeneous mass in the antrum with complete disruption of wall layers and breach of serosa - carcinoma antrum. Though it is not always possible to differentiate between benign and malignant disease on the basis of sonography alone, complete disruption of wall layering and presence of heterogeneous intraluminal masses favoured the diagnosis of malignancy. Wall thickening of a lesser extent (5-8 mm) is also seen in chronic gastritis and gastric ulcer but wall stratification is maintained in these cases [4,5]. Figure 7a. Longitudinal and transverse scans of the fluid filled stomach showing hypoechoic circumferential wall thickening and loss of wall layers.? Scirrhous Carcinoma? Lymphoma. Figure 7b. Barium meal of the same patient showing loss of distensibility of the stomach with small mucosal ulcerations - Scirrhous carcinoma body. Figure 8. Endoscopic biopsy showing glands replaced by columns and cords of malignant cells - diffuse carcinoma. High resolution sonography underestimated the intraluminal extent in 2 cases while endoscopy underestimated the extent in three cases of carcinoma GE junction with involvement of the fundus. On sonography, the involvement of the lower dorsal oesophagus was not identified in one case owing to the inability to visualize it on sonography while in the other the involvement of the fundus was not identified. This was related to the poor visualization of the fundus in this case; the fundus being a difficult area to evaluate on sonography because of overlying ribs [6,7]. In these cases, the involvement of the fundus was missed on endoscopy owing to the inability of the endoscope to negotiate the area of growth / stricture at the GE junction. In the single case of scirrhous carcinoma of the stomach diffuse circumferential wall thickening was seen on sonography (Fig. 7a) and barium showed reduced distensibility with mucosal ulcerations(fig 7b). Endoscopy interpreted the case of scirrhous carcinoma as normal. Owing to the diffuse wall thickening seen on sonography lymphoma was considered in the differential diagnosis in addition to diffuse carcinoma and a repeat endoscopy was undertaken. Repeat endoscopy in this case, revealed small mucosal ulcerations but the endoscopic biopsy was negative. A third repeat endoscopic biopsy revealed it to be a case of diffuse carcinoma (Fig. 8). This may be attributed to the well known difficulty of endoscopy in diagnosing these tumours as the overlying mucosa appears normal, the diagnostic

6 S Singh et al IJRI, 15:4, November 2005 yield is higher in exophytic lesions than in infiltrative lesions [8,9]. Serosal involvement was seen in 13 out of 17 cases of gastric carcinoma (Fig. 9). Out of the four patients where the serosa appeared intact on sonography, serosal involvement with involvement of loco-regional lymph nodes was seen at surgery in 2 cases. Invasion of the pancreas was identified by sonography in two patients. In one case the tumour mass was seen to directly continue in the pancreatic region, in the other case pancreatic infiltration was identified as a focal change in the pancreatic echotexture in the region of the tumour mass. The invasion of the pancreas was confirmed at surgery in both the cases. Simeone et al [10] had shown the role of ultrasound in the assessment of the invasion of pancreas by gastric carcinoma. Invasion of the transverse mesocolon in two patients and invasion of the gastrohepatic and gastrocolic ligaments seen in one patient at surgery was not seen on sonography preoperatively. Derchi et al [11] had stated that when patients of gastric carcinoma are referred for evaluation of liver metastases it is worthwhile to get additional information about tumour extent by performing a complete sonographic examination of ithe abdomen and pelvis and by making an attempt to visualize the primary neoplasm and its relations to surrounding structures. Preoperative knowledge of both local and distant tumour extent may greatly help surgeons to plan more accurately their therapeutic approach and may even obviate the need for laparotomy with far advanced disease who may receive other types of treatment. In our study liver metastases were seen in three patients. Hypoechoic lesions were seen in two patients, both hypoechoic and hyperechoic lesions were seen in the third patient. Para-aortic lymphadenopathy was identified at sonography in four patients. Free fluid was seen in six patients, only four of these patients had presented with ascites clinically. Thus, though sonography underestimated the exogastric extent in a few cases it did provide a rough estimate of the extent in the majority of the cases not available by endoscopy. CONCLUSION:- well as the extent of wall thickness can suggest the diagnosis of malignant lesions. Heterogeneous intraluminal masses, hypoechoic wall echotexture, luminal narrowing, reduced peristalsis and circumferential wall thickening with loss of wall layering suggest a malignant lesion while increased wall thickness with maintained wall stratification suggest a benign lesion. Intraluminal abnormalities, contiguous structures, adjacent extrinsic masses are also well demonstrated. Sonography allows better evaluation of the entire extent of lesions were the endoscope cannot negotiate the proximal growth or area of narrowing in a cost effective manner without any radiation hazard. Thus the study concludes that high resolution sonography of the fluid filled stomach is a supportive diagnostic modality and suggests itself as a supplementary diagnostic procedure to endoscopy. REFERENCES 1. Olearchyk AS: Gastric carcinoma - a critical review of 243 cases. Am J Gastro 1978;70: Yeh HC, Rabinowitz JG : Ultrasonography and computed tomography of gastric wall lesions. Radiology 1981;141: Worlicek H, Dunz D, Engelhard K : Ultrasonic examination of the wall of the fluid filled stomach. J Clin Ultrasound 1989; 17: Fujishima H, Misawa T, Chijiiwa Y, Maruoka A, Akahoshi K, Nawata H : Scirrhous carcinoma of the stomach versus hypertrophic gastritis: findings at endoscopic US. Radiology 1991; 181: Sijbrandij LS, Op den Orth Jo : Transabdominal ultrasound of the stomach : a pictorial essay. Eur J. Radiol 1991; 13: Komaiko MS : Gastric neoplasm : Ultrasound and CT evaluation. Gastrointest Radiol 1979; 4: Walls WJ: The evaluation of malignant gastric neoplasms by ultrasonic B scanning. Radiology 1976; 118: Levine MS, Palman CL, Rubesin SE, Laufer I, Herlinger H : Scirrhous carcinoma of the stomach : radiologic and endoscopic diagnosis. Radiology 1990; 175; Winawer SJ, Posner G, Lightdale CJ, Sherlock P, Melamed M, Fortner JG : Endoscopic diagnosis of advanced gastric cancer. Factors influencing yield. Gastroenterology 1975;69: Simeone JF, Dembner AG, Mueller PR : Invasion of the pancreas by gastric carcinoma : Ultrasonic appearance. J Clin Ultrasound 1980; 8: Derchi LE, Biggi E, Rollandi GA, Cicio GR, Neumaier CE : Sonographic staging of gastric cancer. AJR 1983; 140: Thus high resolution transabdominal sonography of the fluid filled stomach allows unique and detailed evaluation of the gastric wall layers not available by either endoscopy or barium meal. It not only shows the thickened gastric wall but also shows which layers are involved. The pattern of involvement of wall layers, echotexture of the wall as