Clinical Radiology (1990) 42, 410-413

Correlation of lllIndium WBC Scintigraphy with Ultrasound in the Detection and Assessment of Inflammatory Bowel Disease K. T. K H A W , S. H. S A V E R Y M U T T U * and A. E. A. J O S E P H Departments o f Radiology and *Medicine, St George's Hospital, London

mIndium (UlIn) WBC scintigraphy is an accurate method of assessing the extent of inflammatory bowel disease. A prospective study was performed to determine the correlation of ultrasound scanning with rain W B C scintigraphy in the assessment of inflammatory bowel disease. Eighty-three indium and ultrasound scans were performed in 57 patients. Forty-six patients had Crohn's disease and 11 patients had ulcerative colitis. The site and extent of abnormality and the appearance of the bowel were recorded and compared to the findings on indium scintigraphy. Ultrasound detected 84% of indium-positive sites. If the rectum was excluded, sensitivity of detection rose to 91%. Three percent of indium-negative sites were positive on ultrasound. Khaw, K.T., Saverymuttu, S.H. & Joseph, A.E.A. (1990) Clinical Radiology 42, 410-413. Correlation of 1~lIndium WBC Scintigraphy with Ultrasound in the Detection and Assessment of Inflammatory Bowel Disease

The detection and follow-up of inflammatory bowel disease has conventionally been by a combination of clinical assessment, barium contrast studies, endoscopy and biopsy. In recent years, 111Indium (111In) labelled autologous WBC scintigraphy has been increasingly used in the diagnosis and assessment of inflammatory bowel disease (Saverymuttu et al., 1983, 1986; Stein et al., 1983; N a v a b et al., 1987). Its sensitivity has been shown to be greater than that of radiology in detecting disease (Saverymuttu et al., 1982). G o o d correlation has also been found between endoscopy with histology and i llir t scanning in inflammatory bowel disease (Saverymuttu et al., 1986). 11lin scintigraphy is now used routinely in our hospital for the assessment and follow-up of these patients. M a n y studies have shown that gastrointestinal pathology can be demonstrated by ultrasound (Bluth et al., 1979; Fleischer et al., 1980; Dubbins, 1984; Dinkel et al., 1986). In this study we investigated the ability of ultrasound to detect and assess the site, nature and extent of inflammatory bowel disease in relation to the findings "on 111in WBC scintigraphy.

P A T I E N T S AND M E T H O D S Fifty-seven patients with inflammatory bowel disease were included in the study. Forty-six patients had Crohn's disease and 11 had ulcerative colitis. In all patients the diagnosis w a s proven by histology or radiology. The indium and ultrasound scans were carried out as part of the routine assessment and follow-up of patients with both newly diagnosed and established or treated disease. A total of 83 combined indium and ultrasound scans was performed; 12 patients had two scans and seven patients had three scans. In those patients who had more than one scan, follow-up scans were usually performed 3 to 4 months after the previous examination. All patients underwent autologous l l~In WBC scintigraphy with the method previously described by SaveryCorrespondence to: Dr A. E. A. Joseph, Department of Radiology, St George's Hospital, Blackshaw Road, London SW17 0QT.

muttu et al. (1986). In brief, blood was taken from the patient and the granulocytes separated. A pure granulocyte fraction labelled with Ill In tropolonate in plasma was obtained and was re-injected into the patient. Images were obtained on a g a m m a camera at 1, 3 and 24 h after injection and continued at 48 and 72 h if necessary. Ultrasound examination was carried out within 24 h of the injection. The patient was fasted but no other preparation was required. A single operator performed all ultrasound scans using a Technicare Autosector with a 5 M H z frequency transducer. The diagnosis and results of the indium scan were not available to the operator at the time of the ultrasound scan. An attempt was made to locate and examine each part of the bowel; small bowel, ascending, transverse, descending and sigmoid colon and rectum. Involvement was recognized by thickening of the bowel. The site, appearance and pattern of thickening and any complications such as small bowel obstruction, fluid collections and fistulae were noted. Inflammatory activity was localized on the indium scan by accumulation of labelled white cells in bowel on early scans. Later scans (24 h) showed activity in the bowel distal to the original sites which indicated propulsion of bowel contents. An area of abscess formation could be localized by a region of activity which remained static and gradually increased in activity on delayed scans. Table 1 Sites

Results (In +re) (USS +re)

Small bowel Terminal ileum Ascending colon Transverse colon Descending colon Sigmoid colon Rectum

(In +re) (USS -re)

27 40 29 19 15 19 9

3 . 1 3 3 3 1 14

158

28

In +re sites detectedby USS

27/30 40/4l 29/32 19/22 15/18 19/20 9/25

(90%) (97%) (87%) (860/`,) (83%) (95%) (39%)

158/186 (84%)

Two patients with negative ultrasound scans had diffuse activityon the late indium scan which could not be localized-:

ASSESSMENT OF INFLAMMATORY BOWEL DISEASE

The findings on ultrasound examination were then correlated with the 11qn WBC scan and clinical data.

RESULTS Bowel thickening was seen in 52 patients. The sites of thickened bowel found on ultrasound were compared to

Table 2 Site

Results (In --re) (USS --re)

Small bowel Terminal ileum Ascending colon Transverse colon Descending colon Sigmoid colon Rectum

(In --re) (USS +re)

In --re sites which were USS +re

49 40 48 56 62 59 57

2 0 1 3 l 2 1

2/51 0/40 1/49 3/59 1/63 2/61 1/58

(3%) (0%) (2%) (5%) (2%) (3%) (2%)

371

10

10/381

(3%)

Fig. 1 - Small bowel obstruction: fluid filled bowel with prominent valvulae conniventes (arrowed).

Fig. 2 - Matted thickened small bowel (arrowed) with fluid collection

(F).

411

sites of activity on the indium scan. The sensitivity o f detection of indium-positive sites by ultrasound is summarized in Table 1. Ultrasound detected 158/186 (84%) of active sites. The highest rate of detection w a s i n the terminal ileum where 40/41 (97 %) sites were .detected. The lowest was in the rectum where only 9/25 (39%) o f active sites were detected, If the rectum was excluded, the overall sensitivity of detection rose to 149/163 (91%). O f a total of 381 indium negative sites, 10 (3%) were positive on ultrasound (specificity 97%) (Table 2). In two patients (two scans) disease activity could not be localized. No abnormality was seen on ultrasound or on the 1 and 3 h indium scans, but there was faint diffuse colonic activity on the 24 h scan. The appearances were indicative of propulsion of bowel contents from a mildly active inflammatory site, probably in small bowel. Five patients (eight scans) showed no abnormality on ultrasound or indium scan. These were patients who had been treated and were clinically in remission from the disease. The affected bowel was often rigid and aperistaltic. F o u r patients (four scans) had frank mechanical obstruction with dilated, fluid filled, hyperperistaltic bowel in which the valvulae conniventes could be clearly seen (Fig. 1). Fluid collections ranging in size from 2 to 10 cm were seen in seven patients (10 scans). In five patients (seven scans), all with Crohn's disease, complex inflammatory masses of multiple matted bowel loops and small fluid collections were present (Fig. 2). In some patients a thickened mesentery could be seen (Fig. 3). The fluid collections and inflammatory masses were confirmed on the indium scans and none were missed by ultrasound. Three patients with Crohn's disease had fistulae which were demonstrated by ultrasound and barium studies (Fig. 4). These patients were excluded from the final analysis as fistulae caused difficulty in assessment of the exact site of activity in bowel on the indium scan. In addition, two patterns of bowel thickening were identified. In the majority of patients with Crohn's disease (36/46) the affected bowel in transverse section resembled a target lesion with a central hyperechoic area surrounded by a wide hypoechoic region (Fig. 5). In the majority of patients with ulcerative colitis (9/11), the central region was of mixed echogenicity surrounded by a relatively thinner hypoechoic area, which in many cases was

Fig 3 Loop of thickened small bowel (open arrows) with echogenic thickened mesentery centrally (closed arrow).

412

CLINICAL RADIOLOGY

(a)

Fig. 6-Bowel in ulcerative colitis showing poorly defined inhomogenous lumen.

difficult to demarcate from the central echogenic region (Fig. 6).

DISCUSSION

(b) Fig. 4 - (a) Pelvic scan showing bladder (B), thickened rectum (walls marked r) and echogenic, air-containing thin fistulous track (F). (b) Barium enema in same patient showing fistulous track (arrow) communicating with collection (C).

Fig. 5 Target lesion with well-defined lumen in Crohn's disease.

This study is the first to assess disease extent in inflammatory bowel disease using ultrasound in comparison with an independent imaging modality within 24 h. Indium scanning is established as an accurate technique for defining the extent of inflammatory bowel disease compared to colonoscopy (Saverymuttu et al., 1986), with a sensitivity greater than that of radiology in the detection of disease (Saverymuttu et al., 1982). We have shown a good correlation between active sites on the indium scan and ultrasonic abnormality in the bowel. The exception was in the rectum, which, however, can be easily assessed by proctoscopy or sigmoidoscopy. If the rectum was excluded, sensitivity of detection rose from 84% t~ 91%. Nine percent of active sites were considered to be normal on ultrasound. Some of them may have been areas of mild inflammatory activity which did not cause macroscopic change detectable by ultrasound. Conversely, the bowel was considered to be abnormal on ultrasound in 10 of 381 Sites negative on scintigraphy. Some of these may represent bowel where although inflammatory activity was quiescent, residual structural abnormality of the bowel such as fibrosis was present. We recognized two different ultrasonic patterns in the two disease entities. In Crohn's disease the outer hypoechoic region tended to be thick with a well defined echogeni'c lumen; in ulcerative colitis it was thinner and poorly demarcated. These differences in echo pattern are likely to be related to the underl3/ing pathological changes. In Crohn's disease inflammation is transmural, affecting mainly the wall and deeper layers, with relative sparing of the mucosa. In ulcerative colitis, there is mucosal oedema and ulceration with inflammatory debris and exudate shed into the bowel lumen, and the deeper layers are less affected. These differences m a y prove to be

ASSESSMENTOF INFLAMMATORYBOWEL DISEASE useful in differentiating C r o h n ' s disease f r o m ulcerative colitis on u l t r a s o u n d . Bowel gas is c o n s i d e r e d by m a n y to be a limiting factor in the assessment o f bowel by u l t r a s o u n d . It was n o t f o u n d to be a m a j o r d i s a d v a n t a g e in this study. A b n o r m a l bowel was often t h i c k e n e d a n d aperistaltic o r fluid-filled, reducing the a m o u n t o f gas within the lumen, a n d was usually easy to detect. F i r m pressure with the t r a n s d u c e r was helpful. I f a definite a b n o r m a l i t y c o u l d n o t be identified the b o w e l was considered n o r m a l . L i m i t i n g factors in the assessment o f these patients by u l t r a s o u n d were m a i n l y those which limited ultrasonic e x a m i n a t i o n generally s u c h as obesity a n d the presence o f scars, w o u n d s o r dressings on the a b d o m i n a l wall. In this s t u d y no f o r m a l a t t e m p t was m a d e to correlate the i n d i u m scans with o t h e r i m a g i n g m o d a l i t i e s such as r a d i o l o g y , as n u m e r o u s previous studies have d e m o n strated the a c c u r a c y o f i n d i u m s c a n n i n g in the detection and assessment o f i n f l a m m a t o r y b o w e l disease. M a n y cases were for reassessment o n l y a n d the i n d i u m a n d u l t r a s o u n d scans were the only i m a g i n g investigations p e r f o r m e d . Possible sources o f e r r o r in i n d i u m scanning for i n f l a m m a t o r y b o w e l disease, however, include false positive findings which, a l t h o u g h u n c o m m o n , have been r e p o r t e d with c a r c i n o m a or l y m p h o m a , with gastrointestinal bleeding, a n d m a y also be due to swallowed leucocytes where there is r e s p i r a t o r y tract p a t h o l o g y (Fischer a n d R u d d , 1983; M c A f e e a n d Samin, 1985). Large fistulae, collections or m o v i n g l o o p s o f small bowel m a y o c c a s i o n a l l y o b s c u r e o t h e r l o o p s o f affected bowel, m a k i n g it difficult to assess if activity is present in the obscured bowel. It m a y also be difficult to differentiate sigmoid f r o m small bowel in the pelvis if there is localized disease. T h e p r o c e d u r e for labelling leucocytes is lengthy and if p e r f o r m e d incorrectly m a y result in p o o r labelling with an u n d i a g n o s t i c scan. B o t h u l t r a s o u n d a n d i n d i u m scanning are non-invasive and safe even in the severely ill. llJIn W B C scanning however also has the d i s a d v a n t a g e s o f involving r a d i a t i o n and being t i m e - c o n s u m i n g , expensive a n d o f limited availability. The results o f o u r s t u d y show t h a t ultras o u n d is a useful i m a g i n g technique in patients with

413

i n f l a m m a t o r y bowel disease. T h e site o f disease can be localized a n d associated c o m p l i c a t i o n s such as i n f l a m m a t o r y masses, small bowel o b s t r u c t i o n a n d abscesses can be detected. U l t r a s o u n d s h o u l d be p a r t i c u l a r l y useful when r e p e a t e d assessment is necessary to m o n i t o r disease progression, especially in y o u n g w o m e n a n d children in w h o m r e p e a t e d r a d i o l o g i c a l investigations are undesirable.

REFERENCES

Bluth, EI, Merritt, CRB & Sullivan, MA (1979). Ultrasonic evaluation of the stomach, small bowel and colon. Radiology, 133, 677-680. Dinkel, E, Dinrich, M, Peters, H & Baumann, W (1986). Real-time ultrasound in Crohn's disease: characteristic features and clinical implications. Paediatric Radiology, 16, 8-12. Dubbins, PA (1984). Ultrasound demonstration of bowel wall thickness in inflammatory bowel disease. Clinical Radiology, 35, 227-231. Fischer, MF & Rudd, TG (1983). In-11 l-labelled leucocytes imaging; false positive study due to acute gastro-intestinalbleeding. Journal of Nuclear Medicine, 24, 803-804. Fleischer, AC, Muhletaler, MD & Everette James, A (1980). Sonographic patterns arising from normal and abnormal bowel. Radiologic Clinics of North America, 18, 145-159. McAfee, JG & Samin, A (1985). In-11 l-labelled leucocytes: a review of problems in image interpretation. Radiology, 155, 221-229. Morgan, CL, Trought, WS, Oddson, TA, Clark, WM & Rice, RP (1980). Ultrasound patterns of disorders affecting the gastrointestinal tract. Radiology, 135, 129 135. Navab, F, Boyd, CM, Diner, WC, Subramani R & Chan, C (1987). Early and delayed indium-111 leucocyte imaging in Crohn's disease. Gastroenterology, 93, 829 834. Saverymuttu, SH, Camilleri, M, Rees, H, Lavender, JP, Hodgson, HJF & Chadwick, VS (1986). Indium-ll 1 granulocyte scanning in the assessment of disease extent and disease activity in inflammatory bowel disease. Gastroenterology, 90, 1121-1128. Saverymunu, SH, Peters, AM, Hodgson, H J, Chadwick, VS & Lavender, JP (1982). Indium-I 11 autologous leucocyte scanning: comparison with radiology for imaging the colon in inflammatory bowel disease. British Medical Journal, 285, 255-257. Saverymuttu, SH, Peters, AM, Lavender, JP, Hodgson, HJ & Chadwick, VS (1983). Indium-111 autologous leucocytes in inflammatory bowel disease. Gut, 24, 293 299. Stein, DT, Gray, GM, Gregory, PB, Anderson, M, Goodwin, DA & Ross McDougall I (1983). Location and activity of ulcerative and Crohn's colitis by indium-111 leucocyte scan. Gastroenterology, 84, 388 393.

Correlation of 111indium WBC scintigraphy with ultrasound in the detection and assessment of inflammatory bowel disease.

111Indium (111In) WBC scintigraphy is an accurate method of assessing the extent of inflammatory bowel disease. A prospective study was performed to d...
3MB Sizes 0 Downloads 0 Views