Diagnostic Performance of a Commercially Available Computer-aided Diagnosis System for Automatic Detection of Pulmonary Nodules: Comparison with Single and Double Reading

OBJECTIVE

To assess the diagnostic performance of a commercially available computer-aided diagnosis (CAD) system for automatic detection of pulmonary nodules with multi-row detector CT scans compared to single and double reading by radiologists.

MATERIALS AND METHODS

A CAD system for automatic nodule detection (Siemens LungCare NEV VB10) was applied to four-detector row low-dose CT (LDCT) performed on nine patients with pulmonary metastases and compared to the findings of three radiologists. A standard-dose CT (SDCT) was acquired simultaneously and used for establishing the reference data base. The study design was approved by the Institutional Review Board and the appropriate German authorities. The reference data base consisted of 457 nodules (mean size 3.9 +/- 3.1 mm) and was established by fusion of the sets of nodules detected by three radiologists independently reading LDCT and SDCT and by CAD. An independent radiologist used thin slices to eliminate false positive findings from the reference base.

RESULTS

An average sensitivity of 54 % (range 51 % to 55 %) was observed for single reading by one radiologist. CAD demonstrated a similar sensitivity of 55 %. Double reading by two radiologists increased the sensitivity to an average of 67 % (range 67 % to 68 %). The difference to single reading was significant (p < 0.001). CAD as second opinion after single reading increased the sensitivity to 79 % (range 77 % to 81 %), which proved to be significantly better than double reading (p < 0.001). CAD produced more false positive results (7.2 %) than human readers but it was acceptable in clinical routine.

CONCLUSION

Double reading with CAD as second reader offered a significantly increased sensitivity compared to conventional double reading. Thus, CAD is a valuable tool for the detection of pulmonary nodules and should be used as second opinion.

Severe intra-abdominal bleeding following stapled mucosectomy due to enterocele: report of a case

Stapled rectal mucosectomy (SRM) became a widely accepted surgical procedure for haemorrhoids. One of the rare complications is severe bleeding. We report the case of a patient who underwent SRM for thirddegree haemorrhoids. In addition, he suffered symptoms of outlet obstruction, although defecography showed no serious disease. One day after SRM, the patient complained of abdominal pain and peritonitis. Computed tomography revealed blood in the abdomen. The patient underwent laparotomy, which revealed a deep enterocele that reached down to the level of the sphincteric muscle. The ventral part of the stapled ring was placed intraperitoneally, and a longitudinal defect of the rectal serosa was observed. The serosa defect was sutured and a diverting sigmoid stoma was carried out. The patient left the hospital 10 days later. We emphasize vigilance for undetected enteroceles in mucosal prolapse syndrome combined with defecation problems.

Die intraoperative laparoskopische Cholangiografie - Wann ist sie sinnvoll?

Since the introduction of laparoscopic cholecystectomy (LC), a decrease in the practice of intraoperative cholangiography (IOC) has been reported. Are there actually reasons for carrying on IOC during LC? Depending on the management of common bile duct (CBD) stones treatment a different IOC regime is recommended. If the single-stage laparoscopic extraction of ductal calculi during LC is preferred, routine IOC is generally necessary to detect all CBD stones for desobstruction via ductus cysticus or choledochotomy. When therapeutic splitting is favoured, including two-stage management with endoscopic desobstruction and later LC, routine IOC can be foregone. However, selective practice of IOC can help to reduce the rates of unnecessary preoperative investigations from 40-60 % to 20 % when postoperative endoscopic desobstruction demonstrates similar success rates of about 95 %. Regarding the preventive character of laparoscopic IOC to CBD injuries, a routine investigation should be adopted by institutions with injury rates > 0.4 % and in the learning phase of young surgeons. For all other institutions a selective practice should be recommended when difficult intraoperative conditions render recognition of the anatomical situation more difficult or for identification of dissected non-bleeding ducts near the triangle of Calot.

Acceleration of callus maturation using rhOP-1 in mandibular distraction osteogenesis in a rat model

The aim of this study was to assess if the application of rhOP-1 induces accelerated consolidation of the callus in mandibular distraction osteogenesis. In seven adult Wistar rats a bilateral osteotomy of the horizontal ramus of the mandible was performed in the molar region and a custom designed distractor was mounted to the mandible. With a rate of 0.7 mm per day the device was activated bilaterally after the seventh postoperative day. After seven days of distraction two times 50 microg rhOP-1 were injected on two subsequent days directly into the callus. The contralateral side received an injection of placebo solution. The animals were killed four weeks after the end of distraction. A three-point bending test revealed a significantly higher strength of the distracted mandible in the rhOP-1 side (66.3 N vs. 30.4 N, P=0.034, paired t-test). Undecalcified histological sections were examined using microradiography and fluorescence microscopy after sequential intravital polychromic labelling. A continuous bony bridging was seen in all rhOP-1 sites and in none of the control sites. The data indicate that rhOP-1 may be an option to accelerate callus maturation in mandibular distraction osteogenesis.

[Minimally invasive resections of gastric tumors]

BACKGROUND

Submucosal and mucosal gastric tumors occur infrequently and have a highly variable clinical course.

MATERIALS AND METHODS

Between 1996 and 2001, 44 patients with tumors of the stomach wall underwent a laparoscopic local resection in three different procedures and were analyzed prospectively.

RESULTS

Laparoscopic resections were performed on 44 patients (21 female, 23 male). The mean age of the patients was 65.3 years (range: 23-78). We performed the laparoscopic intragastric resection (LIR) on 18, the full thickness resection (LVR) on 17, and the extramucosal enucleation (LER) on 9 patients. The laparoscopic resection was combined with endoscopy in 24 patients. The immunohistological examination of the specimens showed gastrointestinal stroma cell tumors (GIST) in 24 cases, leiomyomas in 10 cases, adenomas in 2 cases, neurinomas or benign neurofibromas in 4 cases, neuroendocrine tumors (NET) in 2 cases, and an ectopic pancreas islet in 1 patient. In all of these patients, the surgical margins in the pathological specimens were tumor-free without lymphatic or venous invasion. None of the patients with GIST or NET had distant metastases. Intraoperative complications occurred in three cases (6.8%). Two repeat laparoscopic procedures (4.6%) were necessary. No fatal outcome or relapse in the follow-up over 23.4 months (range: 1-74) was registered.

CONCLUSIONS

Laparoscopic or laparoendoscopic resection of gastric tumors is practicable with relatively few of complications. The level of patient comfort is high.

[Minimally invasive options for gastric tumors]

INTRODUCTION

Depending on the origin of the tumor tissue, gastric tumors may be more or less accessible for biopsy diagnostics. However, especially submucous tumors present a diagnostic problem. Entity and dignity may remain unclear particularly in larger tumors and may not be clarified before operative excision via gastrotomy and frozen section diagnostics. Similar problems may occur in the diagnostics of epithelial tumors, if a reliable appraisal of the dignity based on forceps biopsy is impossible. To clarify their entity and dignity, tumors can be completely extirpated with minimally invasive techniques.

PATIENTS AND METHODS

Apart from the endoscopic mucosa resection (EMR), laparoscopic intragastric tumor resection and laparoscopic wedge resection were performed, especially in larger tumors. In the period from December 1999 to December 2001, we saw an indication for minimally invasive procedures in 22 patients. There were 5 cases of submucous tumors of unclear entity and 17 epithelial lesions. The epithelial lesions included 12 patients with tumors of unclear dignity and five cases with early gastric carcinomas.

RESULTS

The EMR was performed without complications in all 14 cases. One of the three cases with wedge resection was followed by a gastrectomy for oncological reasons. One early postoperative bleeding occurred, which was controlled laparoscopically. Conversion to open surgery due to technical problems was necessary in two cases of laparoscopic intragastric resection, and in one case a gastrectomy was required for oncological intention.

CONCLUSION

Beside the diagnostic aspect, the mentioned techniques also enable a minimally invasive therapy of locally excisable gastric tumors. In addition to benign and low grade malignant lesions, early gastric carcinomas of the intestinal type present an indication.

[Laparoscopic treatment of small bowel obstruction with intussusception, volvulus and appendicitis caused by an inflammatory Meckel's diverticulum]

Indications and contraindications for diagnostic laparoscopy in cases of intestinal obstructions are discussed in connection with a 16-year-old patient's case report with small bowel obstruction including intussusception, volvulus and appendicitis caused by an inflammatory Meckel's diverticulum. The use of diagnostic laparoscopy in cases of intestinal obstructions is controversial. In the described case we performed completely laparoscopically the derevolving and desusception of the volvulus and intussusception, the appendectomy and resection of the diverticulum. The procedure itself and the postoperative course were uneventful.

[Dose reduction of radiographs of the pediatric pelvis for diagnosing hip dysplasia using a digital flat-panel detector system]

PURPOSE

To evaluate a possible dose reduction in pediatric pelvic radiographs in congenital hip dysplasia using a digital flat-panel system instead of a phosphor-storage system.

MATERIALS AND METHODS

During a six-month period, all pediatric patients referred for pelvic radiography for the evaluation of congenital hip dysplasia were randomly assigned to be examined by either a phosphor-storage system or a digital flat-panel system, whereby the latter system was operated with half the radiation dose. Thirty pairs of radiographs were assessed for the visibility of 16 anatomic details and for 5 orthopedic-radiographic measurements (5-point scale with 1 = excellent; three independent observers). The projection indices of Ball and Kommenda and of Tönnis and Brunken were calculated for all radiographs. The Student's t-test was used to compare the flat-panel and the phosphor-storage radiographs for observers' assessments, patients' age and projection indices.

RESULTS

In a total of 7560 observations, the scores for the visibility of anatomic details and orthopedic-radiographic measurements were respectively 2.72 and 2.64 for the flat-panel system and 2.93 and 2.79 for the phosphor-storage system. No significant differences were found between both systems (p > 0.05) and between patient age and projection indices (p > 0.05).

CONCLUSION

Pediatric pelvic radiographs can be obtained with a digital flat-panel system using half the radiation dose instead of a phosphor-storage system without sacrificing relevant information in the diagnosis of congenital hip dysplasia.

[Glomus tumour of the stomach. A case report]

Glomus tumours are benign neoplasms that usually arise in the skin of the extremities but have infrequently been found to occur in other sites including the stomach. We report on a 71-year-old female with non-specific epigastric pain who was diagnosed as having a small, intramural gastric tumour in addition to a cholecystolithiasis. Intraoperatively, the tumour was investigated by frozen section, but the diagnosis remained inconclusive. The ultimate histological examination showed clusters of uniform epithelioid cells surrounding wide vascular spaces. This led to the diagnosis of a glomus tumour. In a review of the recent literature,we discuss the methods and limitations of preoperative diagnostic measures.

Perioperative Risikoeinschätzung in der Chirurgie - eine Analyse bei 10 395 Patienten

The aim of this study was to perform a risk analysis on the basis of routinely documented variables (age, sex, ASA-classification, priority of operation, malignant disease, intraperitoneal or intrathoracic operation and duration of operation) to identify surgical patients who benefit from a more complex risk assessment.

PATIENTS AND METHODS

In a prospective observational trial we analysed a consecutive series of 10 395 patients who were operated on in our General Surgical Department from January 1996 until December 2000 in respect to in-hospital mortality. The variables were examined in univariate tests. Factors with significant impact were subsequently included in a multiple logistic regression analysis. This was done for all variables and afterwards for each ASA-class separately. Predictive accuracy of the prediction model was calculated by the area under a receiver operating characteristic curve (AUC (ROC)).

RESULTS

The overall mortality was 3.9 %. For ASA-classes 2 to 4 we were able to establish a prediction model by means of multiple logistic regression that identified ASA-classification (Odds Ratio [OR ] ASA-class 3 = 3.7; OR ASA-class 4 = 22.4), age (OR 1.019 per year), duration of operation (OR for duration > or = 240 min = 2.25), intraperitoneal/intrathoracic operation (OR = 4.6), emergency operation (OR = 3.1), and malignant disease (OR = 1.5) as independent predictive factors. Both risk group 1 and risk group 5 were excluded from the analysis because there was no mortality in risk group 1 and too few patients in risk group 5. We found an AUC (ROC) of 91.6 % for the considered ASA-classes.

CONCLUSION

The ASA-classification is a good instrument for the assessment of perioperative mortality. Its predictive power can substantially be improved in the classes 2 to 4 by the variables age, duration of operation, intraperitoneal or intrathoracic operation, priority of operation, and malignant disease.

[Musculoskeletal lymphomas]

Primary lymphomas of bone or skeletal muscle are rare entities. The most frequent among these diseases are primary non-Hodgkin's lymphomas of bone. They account for 3-5% of all bone tumors and 5% of all primary extranodal non-Hodgkin's lymphomas. Primary manifestations of Hodgkin's disease in bone or skeletal muscle are rarities. Primary non-Hodgkin's lymphomas of skeletal muscle are rarities as well. Primary non-Hodgkin's lymphomas of bone can be found in any patient age. A preference exists for the 3.-6. decade of life. The radiographic appearance of these entities resembles other aggressive bone tumors. Their differential diagnosis includes -- depending on the patient's age -- Ewing's sarcoma,malignant fibrous histiocytoma,metastases of small cell tumors and osteomyelitis.Further differential diagnoses are the peripheral primitive neuroectodermal tumor (PNET), osteosarcoma, eosinophilic granuloma and fibrosarcoma. Treatment of primary non-Hodgkin's lymphomas uses combinations of chemotherapy and radiation therapy. Operative treatment is reserved for the treatment of complications. The prognosis of primary non-Hodgkin's lymphomas is reflected by 10-year-survival-rates without recurrence of more than 80% in unifocal manifestations.

Laparoscopic-endoscopic rendezvous resection of gastric tumors

BACKGROUND

Submucosal and mucosal tumors of the stomach display a wide spectrum of histopathologic and prognostic characteristics. Biopsies obtained using endoscopic techniques often do not provide the representative histologic sample needed for further therapeutic decisions.

METHODS

From 1999 to 2002, 18 patients with gastric tumors underwent a combined endoscopic-laparoscopic local resection of the tumors using two different procedures and were prospectively analyzed. Tumors of the posterior wall were resected using laparoscopic intragastral resection (LIR). Tumors located in the anterior wall were resected using lesion-lifting or the laparoscopic wedge resection (LWR) approach.

RESULTS

Laparoscopic resections were performed in 18 patients. The mean age of the patients was 64.4 years (range, 38-81 years). Preoperative preparation included endoscopy with biopsies and histologic examination, ultrasound examination, computed tomography scan, and endoscopic ultrasonography. We performed the LWR on 10 patients and the LIR on 8 patients. After resection, the final immunohistologic examination of the specimens showed gastrointestinal stroma cell tumors in nine cases, neurinomas or benign neurofibrotic tumors in four cases, and one leiomyoma. Four additional patients with mucosal early gastric cancer and high comorbidity risks also underwent a limited full-thickness wedge resection. In all the patients, the surgical margins were tumor free, and no lymphatic or venous invasion was encountered in pathologic specimens. Method-specific complications occurred in one case (perforation of the stomach wall). No fatal outcome had to be registered.

CONCLUSIONS

When selected properly, the laparoscopic-endoscopic approach is considered to be curative and minimally invasive for resection of localized gastric tumors. In cases of histopathologically unknown tumors preoperatively, definitive examination of the complete specimen provides the basis for further therapeutic decisions.

[Chondrosarcoma of the sphenoethmoid complex: Case report]

BACKGROUND

Chondrosarcomas are rare malignant mesenchymal tumors of unknown etiology. Only 5 to 10 % appear in the head and neck region.

PATIENT AND RESULTS

We report the case of a 63 year old woman with a chondrosarcoma of the sphenoethmoidal complex extending into the anterior cranial fossa. The tumor was subtotally resected via an osteoplastic lateral rhinotomy. Postoperatively, a fractionated radiation therapy with carbon ions (Schwerionen) was applied. There was no evidence of recurrence one year after therapy.

CONCLUSION

Recent prognostic improvements of skull base chondrosarcomas by combination of skull base surgery and innovative radiation therapy are discussed and the literature is presented.

[Relationship between lens power in refraction]

BACKGROUND

To achieve emmetropia, several components such as the cornea and lens power, and axial length have to be coordinated. Until now, not much is known about the influence of these factors on each other.

METHODS

A total of 66 healthy subjects were enrolled in this study. Ocular dimensions including anterior chamber depth, lens thickness, vitreous chamber depth, and axial length were measured by A-scan ultrasonography. Corneal radius and corneal refractive power were determined by ophthalmometry. The equivalent lens power was calculated by a method based on the Gullstrand schematic eye.

RESULTS

As expected, a good correlation was found to exist between refraction and axial length. Lens power was independent of refraction, but in emmetropic eyes a good correlation between lens power and axial length could be found. Higher axial length was related to lower values of lens power and vice versa.

CONCLUSION

In emmetropic eyes, deviation of axial length seems to be compensated by lens power and if this mechanism does not function, ametropia results.

[Selenium-based digital radiography of the cervical spine: comparison with screen-film radiography for the depiction of anatomic details]

PURPOSE

To compare selenium-based digital radiography with conventional screen-film radiography of the cervical spine.

MATERIALS AND METHODS

In a prospective study X-ray images of the cervical spine were obtained in 25 patients using selenium- based digital radiography and conventional screen-film radiography. All images were clinically indicated. Selenium-based digital radiography and conventional screen-film radiography were used in a randomized order. Four radiologists independently evaluated all 50 examinations for the visibility of 76 anatomic details according to a five-level confidence scale (1 = not visible, 5 = very good visibility). From the evaluation of these anatomic details scores for the upper and middle cervical spine, the cervicothoracic junction and the cervical soft tissues were calculated. The scores for selenium-based digital radiography and conventional screen-film radiography were compared using Wilcoxon's signed rank test.

RESULTS

From a total of 15,200 observations (608 per patient) the following scores were calculated for selenium-based digital radiography and for screen-film radiography, respectively: Upper cervical spine 3.88 and 3.94; middle cervical spine 4.60 and 4.48; cervico-thoracic junction 3.64 and 2.62; cervical soft tissue 4.47 and 3.46. The differences between the last two scores were statistically significant (p < 0.05).

CONCLUSION

The use of selenium-based digital radiography is superior to conventional screen-film radiography in the depiction of anatomic details of the cervicothoracic junction and the cervical soft tissues.

Abdominal spiral CT in children: which radiation exposure is required?

We decided to test to what extent dose reduction is possible in abdominal spiral computed tomography (CT) in young children without loss of anatomic diagnostic information. A retrospective study was performed of 30 abdominal CT examinations of children aged 3 months to 7 years. These were divided into two groups: group A with reduced radiation exposure (tube current 50 mA, CT dose index CTDIFDA < or =0.83 mGy) and group B with standard radiation exposure (tube current > or =100 mA, CTDIFDA > or =1.66 mGy). Image quality was assessed using a four-part scale ('excellent', 'good', 'sufficient', 'poor') on visual image impression and visibility of 32 anatomical details. Five experienced radiologists read the CT scans independently who were blinded to the examination parameters. Differences in ranked data were evaluated with Wilcoxon's rank sum test. No difference between groups A and B was observed in visual image impression. Detail visibility was significantly lower in group A, but the differences were limited to right upper quadrant structures (portal vein, common bile duct, pancreatic head, adrenals) and to arterial branches. Significant differences in visibility rated as 'poor' were only found for the hepatic, splenic and renal arteries; all other structures showed no difference between groups A and B. A protocol with reduced radiation exposure (50 mA, CTDIFDA < or =0.83 mGy) allowed the demonstration of most anatomic structures in abdominal spiral CT in young children. For the precise demonstration of small details (e.g. structures of the right upper quadrant), a protocol with standard radiation exposure (> or =100 mAs) was superior.

[Surgical management of severe peritonitis]

Despite all the efforts made in the areas of intensive care and surgery, severe peritonitis remains a feared condition that is associated with a high mortality rate. Severe abdominal infections are accompanied with a high level of endotoxin production, resulting in the so called systemic inflammatory response syndrome (SIRS), which is often complicated by multiple organ failure. The surgical eradication of the infectious focus is the most important prerequisite for a successful treatment. According to the severity of the local inflammation, different forms of abdominal lavage can be applied. We analysed patient characteristics and the clinical outcome of 180 patients with diffuse peritonitis, including 36 patients with more than 29 MPI-Points. The mean severity of peritonitis (n = 36) was 33 using the Mannheim Peritonitis Index (MPI). The hospital mortality rate was 58 % in this group.

Contribution of intraoperative cholangiography to incidence and outcome of common bile duct injuries during laparoscopic cholecystectomy

BACKGROUND

In the present study we examined, in a meta-analysis of the literature, the contribution of intraoperative cholangiography (IOC) to incidence, type, and time of diagnosis of common bile duct (CBD) injuries during laparoscopic cholecystectomy (LC).

MATERIALS AND METHODS

Forty of 2104 reports were enrolled for analysis. In 26 reports we found exact information on type, location and repair of 405 major injuries and in a subgroup examination we selected 103 major injuries with detailed information as to the event and size of CBD injury in association with IOC.

RESULTS

The main incidence of CBD injuries was 0.36%. Using the method of routine IOC the incidence was 0.21% and the rate of diagnosis at the time of cholecystectomy 87% in contrast to selective use of IOC with 0.43% and 44.5%. In 405 cases of major CBD injuries, severe injuries predominated in 83.9% of the cases. Reconstruction with the help of a bilio-digestive anastomosis was necessary in 45.7% of all patients. In 34.8% of the cases a second intervention had to be made in the follow-up of 4 years after LC. The analysis of type, severity, recognition, and follow-up of CBD injuries during LC w/wo IOC showed significant advantages for doing routine IOC.

CONCLUSIONS

The use of IOC can avoid severe types of CBD injuries during LC, increase the recognition at the time operation, and influence the success of repair and outcome of the patients.

Caustic acid burn of the upper gastrointestinal tract: first use of endosonography to evaluate the severity of the injury

Judging the severity of an injury after erosions of the upper gastrointestinal tract has been exclusively based on endoscopic inspection. For the first time, we used minimal probe endosonography during initial endoscopy and endoscopical progress observations to improve assessment of injury depth determining the therapy. Nine hours after admitting a patient after acid ingestion, the initial endoscopy and simultaneous endosonography with a 12-MHz minimal endosonographical probe took place. The affected wall sections with macroscopical coagulation necrosis regularly showed a richer echo, broadened first layer, and a low-echo wall edema that had developed under the necrosis. Differences existed between the breadth of the first echo-rich layer and the breadth of the edema below it. The indiscriminability of single wall layers correlated with the intensity of the edema. The initial injury depth was defined based on the depth extension of the wall edema and the discriminability of the layers. In the control examinations, a complete wall edema with limited assessability developed independently of the injury's initial severity. The assessment of injury depth was only possible during a short time span. Differences existed in the regression time of the wall edema. The initial endosonography and diagnostic findings over time showed differences between superficial and deep wall injuries after erosion. In this way, the injury depth could be correctly estimated, thus directly influencing therapy planning.

[New automated microkeratome for trepanation of lamellar keratoplasty]

BACKGROUND/PURPOSE

Lamellar keratoplasty is an established therapy of corneal pathologies without endothelial involvement and the lack of endothelial rejection is one of the major advantages compared to penetrating keratoplasty. The major disadvantages of manually prepared lamellar corneal grafts are the limited mechanical and optical quality but the automated lamellar therapeutic keratoplasty system ALTK (MORIA) is intended to overcome these disadvantages. The purpose of this preliminary work is to investigate histologically and in clinical cases, if the ALTK system can achieve this aim.

PATIENTS AND METHODS

Corneas from two human donors were cut with a 300 microns trephine. After fixation, the stromal bed and the excised cup of one specimen were stained with PAS and examined by light microscopy and the other specimen was analyzed by scanning electron microscopy. In addition, follow-up data of two patients who received such a lamellar graft are reported for the first 9 and 7 months postoperation, respectively.

RESULTS

The lamellar cut of homogeneous depth revealed only minor stromal trauma. Both clinical cases demonstrated only minimal interface haze during follow-up. Despite a remarkably clear cornea, visual acuity improved only slowly because the precise lamellar cut tended to partially reproduce any preexisting irregular astigmatism.

CONCLUSIONS

The ALTK system simplifies and standardizes the trephination of lamellar corneal grafts but a longer follow up is necessary with respect to visual development and preservation of a clear graft.