Imaging manifestations of IgG4-related disease

IgG4-related disease is a multisystem immune-mediated disorder associated with lesions manifesting an IgG4-rich plasma cell infiltrate and often raised serum IgG4 concentrations. The disease can mimic neoplastic, infective, and inflammatory processes due to features such as development of masses or organ enlargement. Prompt consideration of this diagnosis is essential to avoid unnecessary investigations and offer appropriate treatments, which can include steroids and other immunosuppressive agents. Although histology is typically diagnostic, imaging is critical to assess disease burden, determine biopsy targets, and evaluate response to treatment. Characteristic imaging features can also point towards the diagnosis in the absence of biopsy. This review highlights these features, as well as more atypical findings, grouped by organ or system. Differential diagnoses are emphasised. The full spectrum of imaging methods is discussed. Whole-body imaging with integrated 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) has an evolving role in the detection of multi-organ involvement and subsequent follow-up.

Perforation of gastrointestinal tract by poorly conspicuous ingested foreign bodies: radiological diagnosis

Perforation of gastrointestinal (GI) tract by ingested bone fragments, toothpicks and dentures is rare but remains an important life-threatening condition, and the outcomes are poorer when the diagnosis is delayed. Invariably, clinical and radiographic diagnosis is difficult as most patients will have no recollection of ingesting a foreign body, whereas these subtle objects are often not visible on radiographs. In search for the diagnosis, CT is the modality of choice, but ultrasound imaging may be first requested in patients presenting with symptoms of acute appendicitis, cholecystitis, pyelonephritis or pelvic inflammatory disease when an ingested foreign body is not considered. Although ultrasound has limited value in depicting a foreign body, it can frequently uncover secondary signs of perforation. However, the rarity of this condition combined with non-specific clinical presentation and the propensity of these small perforating objects to be subtle makes establishing the correct diagnosis by the radiologist challenging. Therefore, understanding of the appearances of GI perforation seen on CT images or general abdominal ultrasound will aid the radiologist in the diagnosis of this important yet often unsuspected condition. This will lead to earlier diagnosis and surgical management. In this article, we illustrate the spectrum of CT, radiographic and ultrasound imaging features seen in GI perforation caused by swallowed bone fragments, toothpicks, cocktail sticks and dentures.

Applications of transrectal ultrasound in prostate cancer

Transrectal ultrasound (TRUS) was first developed in the 1970s. TRUS-guided biopsy, under local anaesthetic and prophylactic antibiotics, is now the most widely accepted method to diagnose prostate cancer. However, the sensitivity and specificity of greyscale TRUS in the detection of prostate cancer is low. Prostate cancer most commonly appears as a hypoechoic focal lesion in the peripheral zone on TRUS but the appearances are variable with considerable overlap with benign lesions. Because of the low accuracy of greyscale TRUS, TRUS-guided biopsies have become established in the acquisition of systematic biopsies from standard locations. The number of systematic biopsies has increased over the years, with 10-12 cores currently accepted as the minimum standard. This article describes the technique of TRUS and biopsy and its complications. Novel modalities including contrast-enhanced modes and elastography as well as fusion techniques for increasing the sensitivity of TRUS-guided prostate-targeted biopsies are discussed along with their role in the diagnosis and management of prostate cancer.

Ultrasound detection of colonic polyps: perspective

Colorectal cancer is often preventable if the precursor adenoma is detected and removed. Although ultrasound is clearly not one of the widely accepted screening techniques, this non-invasive and radiation-free modality is also capable of detecting colonic polyps, both benign and malignant. Such colon lesions may be encountered when not expected, usually during general abdominal sonography. The discovery of large colonic polyps is important and can potentially help reduce the incidence of a common cancer, whereas detection of a malignant polyp at an early stage may result in a curative intervention. This pictorial review highlights our experience of sonographic detection of colonic polyps in 43 adult patients encountered at our institutions over a 2-year period. 4 out of 50 discovered polyps were found to be malignant lesions, 3 polyps were hyperplastic, 1 polyp was a hamartomatous polyp and the rest were benign adenomas. The smallest of the detected polyps was 1.3 cm in diameter, the largest one was 4.0 cm (mean 1.7 cm; median 1.6 cm). In each case, polyps were discovered during a routine abdominal or pelvic examination, particularly when scanning was supplemented by a brief focused sonographic inspection of the colon with a 6-10 MHz linear transducer. In this paper, we illustrate the key sonographic features of different types of commonly encountered colonic polyps in the hope of encouraging more observers to detect these lesions, which may be subtle.

Provision of a "same-day" ultrasound service in an inner-city NHS trust: report on experience and lessons learned after the first 2 years

AIM

To assess the effect of changing from an "appointment" to a "same-day" ultrasound (US) service on referral pattern, departmental workload, and patient satisfaction.

MATERIALS AND METHODS

To reduce US waiting time of 3 weeks for routine examinations, a "same-day" service was started for outpatients and general practitioner (GP) patients in September 2006. To examine the effect of this change a retrospective assessment was performed of workload during 1 week in June 2006 (appointments only) and the same week in 2008, 22 months after the implementation of the new service. Distance travelled by patients and waiting time was recorded. Patient satisfaction with the service was assessed by questionnaire in September 2008.

RESULTS

Hospital referrals remained stable, but GP referrals increased from 99 to 367 (270%) and distance travelled by patients increased from a median of 3.1 km (range 0.1-12.1 km) in 2006 to 4.8 km (range 0.2-19.8 km) in 2008 (p<0.001). Non-local GP referrals increased from 20/99 in 2006 (20%) to 198/367 in 2008 (54%). The increased workload was managed by flexible working by radiologists and two additional sonographers. Departmental waiting time increased for all patients with same-day patients waiting a median of 35 min (interquartile range 19-60 min). Ninety-one percent (79/87) of same-day patients rated the service excellent or good, but many requested better information on the waiting time.

CONCLUSION

There is a demand from GPs for same-day US, and it is feasible in a large hospital with flexible radiology working and increased sonographic staffing. Unless adjacent hospitals offer a similar service, continuing rise in demand could overwhelm the service.

Observer accuracy in the detection of pulmonary nodules on CT: effect of cine frame rate

AIM

To assess the effect of cine frame rate on the accuracy of the detection of pulmonary nodules at computed tomography (CT).

MATERIALS AND METHODS

CT images of 15 consecutive patients with (n = 13) or without (n = 2) pulmonary metastases were identified. Initial assessment by two thoracic radiologists provided the "actual" or reference reading. Subsequently, 10 radiologists [board certified radiologists (n = 4) or radiology residents (n = 6)] used different fixed cine frame rates for nodule detection. Within-subjects analysis of variance (ANOVA) was used to evaluate the data.

RESULTS

Eighty-nine nodules were identified by the thoracic radiologists (median 8, range 0-29 per patient; median diameter 9 mm, range 4-40 mm). There was a non-statistically significant trend to reduced accuracy at higher frame rates (p=0.113) with no statistically significant difference between experienced observers and residents (p = 0.79).

CONCLUSION

The accuracy of pulmonary nodule detection at higher cine frame rates is reduced, unrelated to observer experience.

Can contrast-enhanced ultrasonography characterize focal liver lesions and differentiate between benign and malignant, thus providing a one-stop imaging service for patients?()

PURPOSE

Contrast-enhanced ultrasonography (CEUS) displays high sensitivity and specificity in characterizing focal liver lesions (FLLs). We attempted to determine how often CEUS provides an unequivocal diagnosis of FLLs that does not require additional imaging studies.

MATERIALS AND METHODS

Seventy-three patients with 146 FLLs were scanned with B-mode, Doppler, and contrast-enhanced US (2 × 2.4 ml SonoVue, low MI, 4-6 MHz curved array transducer, Toshiba Aplio/Siemens-Acuson Sequoia). Data were digitally stored and transferred to a work station with the GE PACS system. Images were reviewed by a consultant radiologist experienced in CEUS and interpreted in accordance with the criteria for characterizing FLLs published by the European Federation of Societies for Ultrasound in Medicine and Biology. Diagnoses were compared with those based on computed tomography (CT) and/or magnetic resonance (MR) findings if these were available. However, our aim was to assess the frequency with which CEUS provided diagnoses that were considered reliable enough to exclude the need for other imaging studies. Therefore, the CEUS diagnoses were not necessarily confirmed by other methods.

RESULTS

Based on CEUS findings alone, 130/146 (89.0%) FLLs could be classified as benign or malignant, and in 118/146 (80.8%) cases, the lesion could be specifically identified. The other 28/146 (19.2%) FLLs could not be characterized based on CEUS data alone. In 58 (80.8%) of the 73 patients with multiple FLLs, CEUS findings were sufficient to establish the benign vs. malignant nature of all the patient's lesions; in 51/73 (69.9%) patients, all the lesions could also be characterized with CEUS. In the remaining cases, at least one lesion required additional imaging to determine whether it was malignant (14/73, 19.2%) or to establish its identity (22/73, 30.1%). In 4/73 (5.5%) patients, CEUS revealed additional lesions not detected on B-mode US.

CONCLUSIONS

CEUS alone was sufficient to classify 89.0% of the FLLs as benign or malignant, and in 80.8% it was also regarded as sufficient to identify the lesion. It served as a one-stop diagnostic test for 80.8% of the patients, reducing the need for CT-MR scans and providing savings in terms of radiation exposure, time, and money.

Imaging of Wegener's granulomatosis

Wegener's granulomatosis is an uncommon multisystemic disorder of unknown aetiology. It is characterized histopathologically by necrotizing granulomatous vasculitis. Most commonly this involves the upper and lower respiratory tract, with pulmonary involvement occurring at some stage of the disease in almost all patients. However, many other organ systems can also be affected including the kidneys, orbits and central nervous system. For this pictorial review, we have assessed the imaging of 155 patients over a 10-year period in order to illustrate characteristic and some of the more unusual imaging features of Wegener's granulomatosis.

Ovarian cancer detected non-invasively by contrast-enhanced power Doppler ultrasound

Overall, about one-third of women operated upon because of suspected ovarian cancer turn out to have benign disease. This proportion will be even higher when the tumours are small. A more accurate method of determining which are malignant would reduce the number of unnecessary referrals to the cancer centre and increase the scope for conservative management. This pilot study of ultrasound and intravenous microbubble contrast in 20 women with small ovarian tumours enabled the identification of all four malignant lesions with good inter-observer agreement. These preliminary findings suggest that intravenous contrast improves the ultrasound identification of small ovarian malignancies and may provide an accurate way of selecting women who require to be referred urgently for surgery under the auspices of a gynaecological oncologist. The remainder might be considered for laparoscopic surgery or even for observation in some cases.

Liver microbubble transit time compared with histology and Child-Pugh score in diffuse liver disease: a cross sectional study

BACKGROUND

A previous pilot study showed that early arrival time of a microbubble in a hepatic vein is a sensitive indicator of cirrhosis.

AIM

To see if this index can also grade diffuse liver disease.

PATIENTS

Thirty nine fasted patients with histologically characterised disease were studied prospectively. Nine patients had no evidence of liver fibrosis, 10 had fibrosis without cirrhosis, and 20 had cirrhosis (five Child's A, seven Child's B, and eight Child's C).

METHODS

Bolus injections of a microbubble (Levovist; Schering, Berlin) were given intravenously, followed by a saline flush. Time intensity curves of hepatic vein and carotid artery spectral Doppler signals were analysed. Hepatic vein transit time (HVTT) was calculated as the time after injection at which a sustained signal increase >10% of baseline was seen. Carotid delay time (CDT) was calculated as the difference between carotid and hepatic vein enhancement.

RESULTS

Diagnostic studies were achieved in 38/39 subjects. Both HVTT and CDT became consistently shorter with worsening disease, as follows (means (SD)): HVTT: no fibrosis 44 (25) s, fibrosis 26 (8) s, Child's A 21 (1) s, Child's B 16 (3) s, and Child's C 16 (2) s; CDT: no fibrosis 31 (29) s, fibrosis 14 (6) s, Child's A 8 (1) s, Child's B 4 (4) s, and Child's C 3 (3) s. These differences were highly significant (p<0.001, ANOVA comparison). A HVTT <24 s and a CDT <10 s were 100% sensitive for cirrhosis (20/20 and 18/18, respectively) but not completely specific: 2/8 subjects with fibrosis had CDT values <10 s and 3/9 had HVTT <24 s.

CONCLUSION

This minimally invasive test shows promise not only in diagnosing cirrhosis but also in assessing disease severity.

Spiral CT pneumocolon: applications, status and limitations

CT pneumocolon is a promising new technique in the diagnosis and management of colon pathology. CT pneumocolon can detect (sensitivity >95%) and stage (accuracy 79%) colorectal cancer and is very accurate in the differentiation of malignant from benign colonic pathologies. It has excellent detection rates for polyps >10 mm in diameter. Several studies using 3D virtual colonoscopy have already proven its high sensitivity and specificity in polyp detection making this technique robust as a screening tool. The combined results for virtual colonoscopy, from all centres, show a sensitivity of >85% in the detection of polyps 10 mm or greater in size, 70-80% for 5-9 mm polyps and an overall specificity of 90%. CT pneumocolon is a safe, non-invasive and cost-effective method for detecting colonic carcinomas and adenomas and correctly identifying which patients need further colonoscopy. The technique is quick, well tolerated and non-operator dependent. It can also image the proximal colon when distal stenoses prevent endoscopic and barium examination. CT pneumocolon is able to identify the features and complications of inflammatory bowel disease. Further research is warranted to fully assess its impact in terms of a screening tool, acceptability, availability and cost benefit.

Ultrasound of focal liver lesions

This paper gives a comprehensive overview of ultrasound of focal liver lesions. Technical aspects such as examination technique and the use of Doppler modes as well as recent developments such as tissue harmonic imaging and microbubble contrast agents are discussed. The clinical significance and sonographic features of various liver lesions such as haemangioma, focal nodular hyperplasia, adenoma, regenerative nodule, metastasis, hepatocellular carcinoma and various types of focal infections are described. With the exception of cysts and typical haemangiomas, definitive characterisation of a liver lesion is often not possible on conventional ultrasound. This situation has changed with the recent advent of ultrasound contrast agents, which permit definitive diagnosis of most lesions. Contrast-enhanced sonography using recently developed contrast-specific imaging modes dramatically extends the role of liver ultrasound by improving its specificity in the detection and characterisation of focal lesions to rival CT and MRI.

Developments in ultrasound contrast media

Ultrasound microbubble contrast agents are effective and safe echo enhancers. An ingenious array of methods are employed to achieve stability and provide a clinically useful enhancement period. Microbubbles enhance ultrasound signals by up to 25 dB (greater than 300-fold increase) due to resonant behaviour. This is used to rescue failed Doppler studies and may be extended to image the microcirculation of tumours and the myocardium using non-linear modes. Functional studies open up a whole range of applications by using a variety of active and passive quantitation techniques to derive indices from the transit of contrast through a tissue of interest. This has been especially successful in the detection of liver metastases and cirrhosis and shows great promise as a clinical tool. It also has great potential in measuring microcirculatory flow velocity. The demonstration that some microbubbles are not just pure blood pool agents but have a hepatosplenic specific phase has extended the versatility of ultrasound. Imaging of this stationary phase with non-linear modes such as phase inversion and stimulated acoustic emission, has improved the sensitivity and specificity of ultrasound in the detection and characterisation of focal liver lesions to rival that of CT and MR.

Do different types of liver lesions differ in their uptake of the microbubble contrast agent SH U 508A in the late liver phase? Early experience

PURPOSE

To compare the uptake of SH U 508A in different types of liver lesions by using stimulated acoustic emission.

MATERIALS AND METHODS

Thirty-seven patients with characterized lesions (metastasis, n = 17; hepatocellular carcinoma, n = 4; hemangioma, n = 9; focal nodular hyperplasia, n = 7) received 2.5 g SH U 508A. After 5 minutes, stimulated acoustic emission was elicited by using a previously described method. Liver and/or lesional differences were assessed with videodensitometry (objective conspicuity score), and two observers assessed each lesion by using a six-point scale (subjective conspicuity score).

RESULTS

Metastases and hepatocellular carcinoma had low stimulated acoustic emission; median objective conspicuity scores were 70% and 68% (all scores were > or =43%), respectively, and subjective conspicuity scores were 2 or higher for both observers. Hemangiomas had reduced stimulated acoustic emission, with more variability; the median objective conspicuity score was 41% (range, 9%-72%), and the median subjective conspicuity scores were 2 (range, 1-4) and 3.5 (range, 1-5) for observers 1 and 2, respectively. Focal nodular hyperplasia had stimulated acoustic emission comparable to that of the liver in all cases; the median objective conspicuity score was -4.7% (all scores were <6%), and the subjective conspicuity score was 1 or lower for both observers. This finding completely separated focal nodular hyperplasia and malignancies. Significant differences were seen between focal nodular hyperplasia and all other lesion types (P < .05).

CONCLUSION

Strong late-phase lesional uptake of SH U 508A is characteristic of focal nodular hyperplasia, is seen in some hemangiomas, and was not observed in malignancies.

Functional CT imaging of the acute hyperemic response to radiation therapy of the prostate gland: early experience

PURPOSE

Functional CT can measure perfusion and permeability. We hypothesized that acute changes could be measured in these indexes following radiation therapy (RT) to the prostate gland.

METHOD

Twenty-two patients with prostatic cancer were studied before and 1-2 and 6-12 weeks after RT. A single section through the prostate was repeatedly scanned after contrast medium bolus injection. Contrast agent clearance per unit volume (alpha/V) and fractional vascular volume (fvv) were calculated using Patlak graphical analysis. Perfusion was calculated as the ratio between maximal rate of tissue enhancement and peak arterial enhancement.

RESULTS

Significant increases in all indexes occurred after RT. Mean perfusion rose from 0.122 to 0.263 ml/min/ml at 1-2 weeks, mean alpha/V increased from 0.0012 to 0.0016 ml/min/ml at 1-2 weeks, and mean fvv increased from 13.7 to 21% at 1-2 weeks. All three indexes remained elevated at 6-12 weeks after the start of RT.

CONCLUSION

Functional CT demonstrated an acute hyperemic response following RT to the prostate gland.

Intrapartum fetal monitoring: past, present, and future

The concept of intrapartum "monitoring" of the fetal heart rate by auscultation has been extant for almost 200 years and by electronic means for more than 30 years. This article explores historical aspects of fetal monitoring, the advent of electronic fetal monitoring and its controversies, and present and future research opportunities to enhance the reliability, validity, and efficacy of fetal monitoring.

Hepatic malignancies: improved detection with pulse-inversion US in late phase of enhancement with SH U 508A-early experience

Twenty consecutive patients with known liver malignancies underwent ultrasonography (US) in conventional B mode and in pulse-inversion mode in the late hepatic-specific parenchymal phase after intravenous administration of SH U 508A, a microbubble US contrast agent. Two experienced readers assessed subjective and objective conspicuity, number of lesions, and smallest lesion diameter in each mode. Subjective and objective conspicuity were improved with pulse-inversion mode, and smaller lesions were depicted with pulse-inversion mode than with conventional B mode, improving the detection of metastases less than 1 cm in size.

Liver lesions: intermittent second-harmonic gray-scale US can increase conspicuity with microbubble contrast material-early experience

The authors investigated the effect of intermittent second-harmonic gray-scale (ISHGS) ultrasonography (US) with SH U 508A microbubbles on the conspicuity of focal liver lesions. Twenty-three patients were included in the study. Images were analyzed subjectively and quantitatively. Objective lesion conspicuity was increased. In 12 of the 15 patients with liver malignancy, gray-scale defects were seen in previously unsuspected areas. ISHGS US may improve the sensitivity of US for liver lesions.

MR angiographic diagnosis of cerebral venous sinus thrombosis following allogeneic bone marrow transplantation

Allogeneic bone marrow transplantation is frequently associated with neurological complications, particularly intracerebral bleeds and infections. Cerebral venous sinus thrombosis has only rarely been reported following allogeneic transplants. We report three cases of cortical venous thrombosis following allografting for acute lymphoblastic leukaemia. Two patients received marrow from HLA-identical siblings and one from an unrelated donor. Two of the patients presented with grand mal seizures and one presented with a headache. No neurological abnormalities were found upon clinical examination and lumbar puncture was normal in all three cases. In two of the patients computed tomography (CT) of the brain was normal and in the third showed non-specific abnormalities. Magnetic resonance imaging (MRI) with MR angiography (MRA) demonstrated cerebral venous sinus thrombosis in all three patients. In conclusion, cerebral venous sinus thrombosis should be considered in the differential diagnosis when neurological symptoms occur following allogeneic bone marrow transplantation. We therefore advocate the use of MRA for unexplained neurological symptoms post-allograft since without it cerebral venous sinus thrombosis may easily be missed.

Pulse-inversion mode imaging of liver specific microbubbles: improved detection of subcentimetre metastases

Pulse-inversion mode (a new ultrasound mode) can be used to image the late liver-specific parenchymal phase of the microbubble contrast-agent Levovist. Scanning in pulse-inversion mode after Levovist improves the detection of liver metastases and reveals more lesions of smaller size than conventional ultrasonography and computed tomography.

Functional renal perfusion imaging with colour mapping: is it a useful adjunct to spiral CT of in the assessment of abdominal aortic aneurysm (AAA)?

AIM

To ensure optimal timing with pre-operative spiral CT for abdominal aortic aneurysms (AAA), an initial 'timing' single level CT is commonly performed with a small bolus of contrast. This can be exploited to obtain adjunct functional information on renal perfusion. We have investigated the potential of this to measure renal perfusion, to produce colour renal perfusion maps and to predict surgical outcome in infrarenal aortic aneurysm assessment.

METHODS

We studied 21 patients being assessed for repair of infrarenal AAA. Prior to the spiral CT, a single level through the renal hili and aorta was scanned after the intravenous injection of 25 ml of contrast given at 10 ml/s. Ten 1 s duration scans were performed from 8 to 30 s after injection. Optimal timing for CT angiography can then be determined. Time-density curves were then drawn for both kidneys and aorta using regions of interest (ROIs) or pixel-by-pixel analysis. Renal cortical perfusion was measured using both ROI analysis and pseudocolour perfusion images. Following previous work, perfusion was calculated as the peak upslope of the tissue time density curve divided by peak aortic enhancement.

RESULTS

Cortical mean perfusion averaged 2.48 ml/min per ml (range 0.8-3.7 ml/min per ml n = 34) and the values obtained agreed with literature expectations. Follow up in the 10 patients proceeding to AAA repair suggest low mean perfusion values and predict a raised postoperative creatinine (P < 0.05)

CONCLUSIONS

Additional functional data and imaging can be obtained from the initial timing scan of a CT study, without requiring a dedicated study.

Evacuation proctography: a prospective study of diagnostic and therapeutic effects

PURPOSE

To determine the diagnostic and therapeutic effects of evacuation proctography.

MATERIALS AND METHODS

Forty-seven referring clinicians completed preevacuation proctography questionnaires for 50 patients, detailing diagnoses, confidence in these, intended management, and what they hoped to learn. After evacuation proctography, the radiology report was returned with a second questionnaire asking the diagnosis in the light of evacuation proctographic findings, their confidence, and what they had learned. Clinicians quantified management contribution and indicated how useful they found evacuation proctography in general. Results from pre- and post-evacuation proctography questionnaires were compared to determine the diagnostic and therapeutic effects.

RESULTS

Diagnostic confidence rose significantly after evacuation proctography (mean, 7.0 before evacuation proctography vs 8.4 after evacuation proctography; P < .001). Lead diagnosis changed in nine (18%) patients. Intended surgical management became nonsurgical after evacuation proctography in seven (14%) patients, and intended nonsurgical therapy became surgical in two (4%). Surgery remained likely in 15 patients, but its nature changed in five (10%). Five (10%) clinicians stated that evacuation proctographic findings resolved diagnostic conflict, and nine (18%) found that evacuation proctographic findings revealed unsuspected diagnoses. Clinicians found evacuation proctography of major benefit in 20 (40%) cases studied and of moderate benefit in 20 (40%). In general, 20 (43%) clinicians found evacuation proctography very useful and 24 (51%) found it moderately useful.

CONCLUSION

Evacuation proctography has a substantial diagnostic and therapeutic effect and is of considerable benefit to referring clinicians.

Aeromedical transfer of preterm labor patients

Obstetric patients are transported by air quite frequently. We evaluated transport times, obstetric outcomes, air-versus-ground transport costs, and related data on 22 helicopter aeromedical transports of pregnant patients with preterm labor. We found no significant differences between patients who delivered and those who did not when comparing transport time (167.1 +/- 41.9 minutes versus 177.1 +/- 56.2 minutes), air distance of transport (122.9 +/- 44.8 miles versus 143.6 +/- 23.8 miles), and other outcome measures. No deliveries occurred in flight. Air transport costs were significantly greater than estimated ground transfer ($4613.64 +/- $581.12 versus $604.02 +/- $306.38; P < .01). Two-way air transfer of preterm labor patients over moderate distances is more costly than contracted ground transfer costs at our institution.

The radiological investigation of lumbar spondylolysis

Lumbar spondylolysis represents a stress fracture of the pars interarticularis and occurs most commonly at the L5 level. Pars defects can be imaged with plain radiography, bone scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI). Plain radiographic projections of particular value include the coned lateral view of the lumbosacral junction, which displays the majority of defects, and the anteroposterior view with 30 degrees cranial angulation. The value of oblique radiography is unproven. Planar bone scintigraphy (PBS) is more sensitive than radiography and single photon emission computed tomography (SPECT) more sensitive and specific than PBS. Both these techniques, however, are less specific than radiography and CT. CT, when performed with a reverse gantry angle and thin sections, is the investigation of choice for identifying radiographically occult lyses. Conventional lumbar spine MRI techniques are valuable for demonstrating normality of the pars, but may be associated with a high false positive rate for the diagnosis of pars defects.

Helical CT pneumocolon to assess colonic tumors: radiologic-pathologic correlation

OBJECTIVE

The objective of this study was to determine the accuracy of helical CT pneumocolon in the staging of colonic carcinomas.

SUBJECTS AND METHODS

Fifty-two patients (27 men, 25 women; age range, 40-88 years old; mean age, 67 years old) with known or strongly suspected colonic disorders underwent CT pneumocolon. After bowel cleansing, administration of smooth muscle relaxant, and rectal air insufflation, CT pneumocolon was performed with 5-mm collimation, 2.5-mm reconstruction interval, and a pitch of 1.5. Two contrast administration protocols were used. Twelve patients received 100 ml of i.v. contrast material that was injected at 3 ml/sec; scan delay was 45 sec. The other 40 patients received 150 ml of contrast material at 5 ml/sec; scan delay was 25 sec. Images were prospectively evaluated. All patients had pathologic confirmation: 46 patients had resections and six patients had endoscopic biopsies.

RESULTS

Diagnostic images were obtained in 47 of 52 patients. In the 47 patients, there were 38 colonic carcinomas (one synchronous), nine diverticular strictures, eight polyps, one ischemic stricture, and one normal study. Thirty of 38 carcinomas were correctly staged by CT. Sensitivity and specificity for serosal infiltration were 100% (35/35 carcinomas) and 33% (one of three carcinomas), respectively; sensitivity and specificity for lymph node involvement were 56% (nine of 16 carcinomas) and 95% (21/22 carcinomas), respectively. Four polyps that were smaller than 5 mm in diameter were not revealed by CT. Twelve of 14 benign lesions were correctly diagnosed and two were believed to be malignant. No malignant lesion was misdiagnosed.

CONCLUSION

CT pneumocolon gave an overall staging accuracy of 79% in 38 carcinomas.

Cardiopathia fantastica exposed by rapid sequential serum creatine kinase analysis

Rapid, sequential serum creatine kinase measurements may be used to exclude acute myocardial infarction in patients presenting with acute chest pain. Two cases of cardiopathia fantastica (the cardiac variant of Munchausen's syndrome) are described. Both patients presented with symptoms of acute myocardial infarction and had electrocardiographic changes consistent with this diagnosis. Both patients also had a raised serum creatine kinase level at the time of presentation but were unable to mimic the rise in serum creatine kinase associated with acute myocardial infarction. Munchausen's syndrome was suspected when both patients responded poorly to news that their enzyme results excluded acute myocardial infarction.

Protease activity in a hapten-induced model of ulcerative colitis in rats

Inflammatory bowel disease (IBD) is a painful and debilitating condition affecting the mucosal lining of the colon and other areas of the gastrointestinal tract. IBD generally falls into two major categories: ulcerative colitis (UC) and Crohn's disease. We have utilized dinitrobenzenesulfonic acid (DNBS) to induce experimental UC in rats. Histopathologic analysis indicates that DNBS induces a condition in animals similar to human UC. Biochemical results revealed 6- to 10-fold elevated levels of serine protease activity in colon tissue from animals with UC as compared with matched controls. We also observed elevated levels of protease activity in tissue samples obtained from human patients with UC. Hence, our results demonstrate that protease activity is increased in rodent and human UC. These proteases may play a significant role in destruction of colonic tissue in IBD. Protease inhibitors that target serine proteases may be useful pharmacological agents to limit tissue destruction in IBD.

ATP-induced killing of mycobacteria by human macrophages is mediated by purinergic P2Z(P2X7) receptors

The death of BCG-infected human macrophages induced in vitro by ligation of surface CD95 (Fas), CD69, or complement-mediated lysis was shown not to result in the death of intracellular mycobacteria, whereas exposure to extracellular ATP initiated both macrophage death and killed the intracellular bacteria. ATP acted via P2Z receptors because these effects were mimicked by benzoylbenzoic ATP (a known agonist of P2Z receptors) and blocked by oxidized ATP, DIDS, suramin, amiloride, and KN62 (known inhibitors of P2Z-mediated responses). ATP-mediated bacterial killing was independent of reactive nitrogen and oxygen intermediates and of actinomycin D or cycloheximide inhibition. ATP-induced macrophage cell death, BCG killing, and lucifer yellow dye incorporation were minimal in 2 out of 19 healthy donors. The results suggest possible genetic heterogeneity of this mechanism of mycobacterial killing associated with P2Z-mediated pore formation.

Sagittal vertebral body fractures: magnetic resonance imaging features

Isolated sagittal vertebral body fractures are rare and the plain radiographic diagnosis may be difficult. We report two cases, confirmed by CT, and describe the subtle MRI features which comprised increased signal intensity only on the midline sagittal T2 weighted images. In one case, the information from MRI significantly altered the patient's management by leading to a change from surgical to conservative treatment.

Comparison of jet and ultrasonic nebulizer pulmonary aerosol deposition during mechanical ventilation

Increased delivery of aerosol to a model lung (attached to a mechanical ventilator) has been demonstrated with an ultrasonic nebulizer as compared to a jet nebulizer. This study examined whether the increased aerosol deposition with an ultrasonic nebulizer could also be demonstrated in vivo. Seven patients (6 male and 1 female) were studied during mechanical ventilalion (Siemens Servo 900C, Middlesex, UK) after open heart surgery. Two studies were performed in each patient. In the first study, aerosol was delivered via a Siemens Servo 945 nebulizer system (high setting) driving a System 22 Acorn jet nebulizer (Medic-Aid, Sussex, UK) containing 3 mL (99m)technetium-labelled human serum albumin (99mTc-HSA) (50 microg; activity 74 MBq). In the second study, a DP100 ultrasonic nebulizer (DP Medical, Meylan, France) containing 12 mL 99mTc-HSA (50 microg; activity 185 MBq) was used. Pulmonary deposition was quantified using a gamma camera. The humidification of the circuit and the ventilator settings were kept constant according to the patient's clinical requirements. The total lung aerosol deposition (mean+/-SD), as a percentage of initial nebulizer activity, was greater using the ultrasonic nebulizer than using the jet nebulizer (53+/-1.4 vs 2.3+/-0.9%; p<0.002). The ultrasonic nebulizer was also associated with a reduction in the time required to complete nebulization (9 vs 21 min, respectively) (p<0.0001). Use of the DP100 ultrasonic nebulizer more than doubled lung deposition compared with the System 22 jet nebulizers in mechanically-ventilated patients. Their efficiency, speed of drug delivery, and compatibility with mechanical ventilator circuits make ultrasonic nebulizers potentially attractive for use during mechanical ventilation.

Comparison of jet and ultrasonic nebulizer pulmonary aerosol deposition during mechanical ventilation

Increased delivery of aerosol to a model lung (attached to a mechanical ventilator) has been demonstrated with an ultrasonic nebulizer as compared to a jet nebulizer. This study examined whether the increased aerosol deposition with an ultrasonic nebulizer could also be demonstrated in vivo. Seven patients (6 male and 1 female) were studied during mechanical ventilalion (Siemens Servo 900C, Middlesex, UK) after open heart surgery. Two studies were performed in each patient. In the first study, aerosol was delivered via a Siemens Servo 945 nebulizer system (high setting) driving a System 22 Acorn jet nebulizer (Medic-Aid, Sussex, UK) containing 3 mL (99m)technetium-labelled human serum albumin (99mTc-HSA) (50 microg; activity 74 MBq). In the second study, a DP100 ultrasonic nebulizer (DP Medical, Meylan, France) containing 12 mL 99mTc-HSA (50 microg; activity 185 MBq) was used. Pulmonary deposition was quantified using a gamma camera. The humidification of the circuit and the ventilator settings were kept constant according to the patient's clinical requirements. The total lung aerosol deposition (mean+/-SD), as a percentage of initial nebulizer activity, was greater using the ultrasonic nebulizer than using the jet nebulizer (53+/-1.4 vs 2.3+/-0.9%; p<0.002). The ultrasonic nebulizer was also associated with a reduction in the time required to complete nebulization (9 vs 21 min, respectively) (p<0.0001). Use of the DP100 ultrasonic nebulizer more than doubled lung deposition compared with the System 22 jet nebulizers in mechanically-ventilated patients. Their efficiency, speed of drug delivery, and compatibility with mechanical ventilator circuits make ultrasonic nebulizers potentially attractive for use during mechanical ventilation.

The efficacy of intrapartum fetal surveillance when fetal pulse oximetry is added to cardiotocography

OBJECTIVE

To determine if oxygen saturation measurement with pulse oximetry (SpO2) in combination with cardiotocograghy (CTG), improves the assessment of the intrapartum fetal condition.

STUDY DESIGN

Four expert obstetricians individually evaluated 119 cases that were monitored during labor: during the first session the CTG data were available, and in the second session CTG and SpO2 data were evaluated. They were instructed to indicate the need for intervention and to estimate the umbilical artery pH.

RESULTS

In the non-acidotic group (umbilical artery pH > or = 7.15, n = 112) the average(+/-S.D.) number of interventions decreased from 27(+/-17) to 16(+/-9) when SpO2 was available. This reduction in number of interventions resulted in an significantly increased specificity for two referees. In the acidotic group (n = 7) the average number of interventions also decreased, from 6(+/-2) to 4(+/-2), and as a consequence the sensitivity decreased. The pH estimate based on CTG + SpO2 was higher in both acidotic and non-acidotic fetuses than the estimated pH based on CTG alone.

CONCLUSION

In this study all referees intervened less frequently when SpO2 was used as an adjunct to CTG. This resulted in fewer unnecessary operative interventions, but may also lead to unidentified fetal acidosis. The number of acidotic newborns (n = 7) was too small, however, to draw definite conclusions. Larger studies should address the efficacy of SpO2 in detecting fetal compromise before clinical use can be advocated.

Effect of pregnancy on maternal oxygen saturation values: use of reflectance pulse oximetry during pregnancy

Our objective was to evaluate the usefulness of pulse oximetry monitoring in a large population of pregnant patients. We designed our study to measure pulse oximetry saturation in a cross section of 952 obstetric inpatients and outpatients. A group of 366 patients identified as normal were compared with abnormal subgroups. A subgroup of 64 patients with saturation measurements less than 96% were further evaluated. Our results indicated that oxygen saturation values did not change appreciably during the course of pregnancy in normal patients. Hypoxemia (saturation measurement less than 96%) was associated with smoking, and hypoxemia with preterm labor occurred more frequently in patients who smoked. Obesity and magnesium sulfate use appeared to be synergistic in the presence of hypoxemia. We concluded that the routine use of pulse oximetry during pregnancy may not be justified. Smoking, obesity, and magnesium sulfate use have some effect on oximetry in pregnant patients.

Serial measurements of serum creatine kinase are of most use in the exclusion of acute myocardial infarction in patients with a history of heart disease

Rapid sequential measurements of serum CK were assessed in the diagnosis and exclusion of acute myocardial infarction (MI) in 94 patients presenting to St Thomas' Hospital, London, with acute chest pain of less than 12 h duration. A blood sample was taken from patients on admission to hospital and then a second sample was taken within 12 h of admission. Serum CK activity was assayed on both samples and delta log10 (serum CK) per hour calculated to distinguish infarct from non-infarct using a discriminant value of 0.015. Ninety-six per cent of patients with acute MI were diagnosed on the basis of clinical history and electrocardiographic evidence alone, and did not require biochemical confirmation. Serial estimation of serum CK contributed positively towards the exclusion of acute MI in 77% of patients who presented with chest pain and who had a previous history of heart disease, but towards only 11% of cases in the absence of a history of heart disease.

An uncommon intestinal manifestation of feline infectious peritonitis: 26 cases (1986-1993)

OBJECTIVE

To provide information on an uncommon intestinal manifestation of feline infectious peritonitis (FIP).

DESIGN

Retrospective case series.

ANIMALS

26 cats with FIP that had apparently solitary mural intestinal lesions.

PROCEDURE

Histologic records of cats for which FIP had been diagnosed by examination of the surgical biopsy specimens were reviewed. Slides of tissue samples from cats identified in the histologic record as having had intestinal lesions were reviewed by the investigators, and records of cats that appeared to have had solitary mural intestinal lesions were included in the study. Information including signalment; history; physical examination findings; results of hematologic, serum biochemical, and serologic analyses; findings at surgery; and results of histologic examination of biopsy specimens were retrieved from these records and supplemented by medical records and additional information obtained from veterinarians submitting the biopsy samples. ABC immunoperoxidase staining was used to detect FIP virus antigen in tissues from cats whose records were selected for inclusion in the study.

RESULTS

26 of 156 cats with a histologic diagnosis of FIP had apparently solitary mural intestinal lesions. Predominant clinical signs were diarrhea and vomiting for 3 months or less before biopsy. All cats had a mass, believed to be a neoplasm, in the colon or ileocecocolic junction. Affected intestine was markedly thickened, nodular, firm, and white, with multifocal pyogranulomas extending throughout the wall of the intestine on histologic examination. Associated lymph nodes were large. Results of immunohistochemical staining were positive for FIP virus. Most cats were euthanatized or died within 9 months of histologic results, many with signs of multisystemic FIP.

CLINICAL IMPLICATIONS

The apparent focal nature of intestinal lesions at surgery leads to a different clinical picture than usually seen with FIP, and masses often are believed to be neoplasms. Diagnosis of FIP is important to prevent exposure and infection of other cats. Evaluation of the entire abdominal cavity, biopsy of visible lesions as well as surrounding organs, and postmortem examination are recommended.

The effects of maternal position and cardiac output on intrapulmonary shunt in normal third-trimester pregnancy

OBJECTIVE

To assess the effect of pregnancy, maternal position, and cardiac output on intrapulmonary shunting (Qs/Qt) in normotensive nulliparous women near term.

METHODS

Ten normotensive nulliparas between 36 and 38 weeks' gestation underwent pulmonary artery catheterization (via the subclavian route) and radial artery canalization. Baseline assessments were made with subjects in the left lateral recumbent position after a 30-minute stabilization period. Measurements were obtained sequentially in the left lateral, right lateral, supine, knee-chest, sitting, and standing positions. Each position change was followed by a 10-minute pre-measurement stabilization period. Cardiac output was measured via the thermodilution technique. Blood samples were obtained simultaneously from the pulmonary and radial arteries and analyzed in duplicate for oxygen content with a blood gas analyzer. Qs/Qt was calculated using the classic shunt equation. Statistical analysis was performed by analysis of variance of repeated measures of Qs/Qt and maternal position. The relationship of Qs/Qt to maternal cardiac output was evaluated by the correlation coefficient. Significance was defined as P < .05.

RESULTS

Directly measured Qs/Qt averaged 15.3% in left lateral, 15.2% in right lateral, 13.9% in supine, 12.8% in knee-chest, 13.8% in sitting, and 13.0% in standing positions. There was no statistically significant correlation between Qs/Qt and cardiac output (R2 = 0.11, not significant).

CONCLUSION

This is the first report of directly measured Qs/Qt in normal pregnant women in the third trimester. Qs/Qt values reported in pregnancy are higher than those reported in nonpregnant individuals.

Third-trimester arterial blood gas and acid base values in normal pregnancy at moderate altitude

OBJECTIVE

To report arterial blood gas and acid base values of normal nulliparous patients at moderate altitude for commonly used maternal positions.

METHODS

Ten normotensive nulliparous women between 36 and 38 weeks' gestation volunteered to undergo radial and pulmonary artery cannulation as part of a larger study. Following instrumentation, baseline assessments were made in the left lateral recumbent position after a 30-minute stabilization period. Sequential measurements were then obtained in the left lateral, right lateral, supine, knee-chest, sitting, and standing positions. Blood samples were analyzed in duplicate for oxygen content on a blood gas analyzer. Statistical analysis was performed by analysis of variance of repeated measures with significance defined at P < or = .05.

RESULTS

There was no significant difference in arterial blood gas or acid base values between any positions in this antepartum population of term healthy women. The composite mean values were as follows: pH 7.46, arterial carbon dioxide pressure (PaCO2) 26.6 mmHg, arterial oxygen pressure 88.3 mmHg, bicarbonate 18.2 mEq/L, saturated arterial hemoglobin level 0.96.

CONCLUSION

Arterial blood gas and acid base values are not altered by maternal position in the late third trimester of pregnancy. The PaO2 in these women studied at moderate altitude was lower than previously reported for healthy pregnant women studied at sea level. Appropriate interpretation of arterial blood specimens of pregnant women should take into account both the pregnancy and altitude at which the women reside.

Gastrointestinal permeability and absorptive capacity in sepsis

OBJECTIVE

To assess gastrointestinal permeability and functional absorptive capacity in patients with sepsis.

DESIGN

Case control study to analyze gastrointestinal permeability and functional absorptive capacity of septic patients by differential saccharide absorption (from an oral test solution) and excretion.

SETTING

The intensive Therapy Unit of St. Thomas' Hospital, London, UK.

PATIENTS

Twenty patients with a mean Acute Physiology and Chronic Health Evaluation (APACHE) II score of 18.4 who were admitted to the intensive care unit with a diagnosis of sepsis. All patients were on enteral feeding. Patients with abdominal pathology were excluded.

INTERVENTIONS

An oral test solution containing 5 g of lactulose, 1 g of L-rhamnose, 0.5 g of D-xylose, and 0.2 g of 3-O-methyl-D-glucose dissolved in water to a final volume of 100 mL was administered to patients and controls. Urine was collected for 5 hrs starting immediately after administration of the test solution and the saccharide content of the urine was estimated and expressed as a percentage recovery of the oral test solution.

MEASUREMENTS AND MAIN RESULTS

Septic patients had increased lactulose/L-rhamnose urine excretion ratios (0.23 +/- 0.19) compared with control subjects (0.03 +/- 0.01, p < .001), consistent with increased gastrointestinal permeability in sepsis. Septic patients had decreased L-rhamnose/3-O-methyl-D-glucose urine excretion ratios (0.14 +/- 0.07) compared with normal controls (0.28 +/- 0.08, p < .001), consistent with decreased gastrointestinal functional absorptive capacity in sepsis.

CONCLUSIONS

Patients with acute sepsis exhibit increased gastrointestinal permeability and decreased gastrointestinal functional absorptive capacity in comparison with healthy control subjects. These abnormalities may contribute to the pathophysiology of sepsis.