Diagnostic accuracy of acute diverticulitis with unenhanced low-dose CT.

BACKGROUND: The aim of this study was to evaluate the diagnostic accuracy of unenhanced low-dose CT (LDCT) in acute colonic diverticulitis in comparison with contrast-enhanced standard-dose CT (SDCT). METHODS: All patients with clinically suspected diverticulitis who underwent LDCT followed by SDCT between January and October 2017 were evaluated prospectively. CT examinations were assessed for signs of diverticulitis, complications and other differential diagnoses by three independent radiologists (two consultants and one fourth-year resident) using SDCT as the reference method. Sensitivity and specificity were calculated and Cohen's κ coefficient was used for agreement analyses. RESULTS: Of the 149 patients included (mean age 66·7 years, M : F ratio 0·4), 107 (71·8 per cent) had imaging consistent with diverticulitis on standard CT. Sensitivity and specificity values for a diverticulitis diagnosis using LDCT were 95-99 and 86-100 per cent respectively, and respective values for identification of complications were 58-73 and 78-100 per cent. The corresponding κ values among the three readers for diagnosis were 0·984, 0·934 and 0·816, whereas κ values for complications were 0·680, 0·703 and 0·354. Of the 26 patients who presented with other causes of abdominal symptoms identified on standard CT, 23 were diagnosed correctly on LDCT. Missed cases included splenic infarction (1) and segmental colitis (2). CONCLUSION: The diagnostic accuracy of LDCT was high for the presence of acute diverticulitis. However, as signs of complicated disease can be missed using the low-dose protocol, use of LDCT as a primary examination method should not preclude SDCT when complications may be suspected.

ANTECEDENTES: Evaluar la precisión diagnóstica de la tomografía computarizada de dosis baja (low-dose computed tomography, LDCT) sin contraste frente a la TC con dosis estándar (standard-dose CT, SDCT) con contraste en la diverticulitis aguda de colon. MÉTODOS: Todos los pacientes con sospecha clínica de diverticulitis aguda de colon a los que se realizó una LDCT seguida de una SDCT entre enero y octubre de 2017 se evaluaron prospectivamente. Tres radiólogos independientes (dos consultores y un residente de cuarto año) analizaron los signos de diverticulitis, complicaciones y otros diagnósticos diferenciales, utilizando la SDCT como método de referencia. Se calculó la sensibilidad y la especificidad, utilizándose el coeficiente κ de Cohen para los análisis de concordancia entre observadores. RESULTADOS: De los 149 pacientes incluidos en el estudio (edad media 66,7 años, varón/mujer 0,4), 107 (71,8%) presentaban unas imágenes compatibles con diverticulitis en la SDCT. La sensibilidad y la especificidad para el diagnóstico de diverticulitis con la LDCT variaban entre el 95-99% y el 86-100%, respectivamente. La sensibilidad y la especificidad para la identificación de complicaciones oscilaron entre el 58-73% y el 78-100%, respectivamente. Los valores κ entre observadores para el diagnóstico fueron del 0,98, 0,93 y 0,82, respectivamente, mientras que para las complicaciones fueron del 0,68, 0,70 y 0,35. De los 26 pacientes en los que la SDCT identificó otras etiologías como causa de sus síntomas abdominales, 23 fueron diagnosticados correctamente con la LDCT. Los casos con diagnóstico erróneo correspondían a un infarto esplénico y dos colitis segmentarias. CONCLUSIÓN: La precisión diagnóstica de la LDCT fue alta para detectar una diverticulitis aguda. Sin embargo, el protocolo de dosis baja puede no identificar los signos de la enfermedad complicada. Por lo tanto, su utilización como método de exploración primario no debe excluir la SDCT cuando se sospechen complicaciones.

The first joint ESGAR/ ESPR consensus statement on the technical performance of cross-sectional small bowel and colonic imaging.

OBJECTIVES: To develop guidelines describing a standardised approach to patient preparation and acquisition protocols for magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US) of the small bowel and colon, with an emphasis on imaging inflammatory bowel disease. METHODS: An expert consensus committee of 13 members from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) and European Society of Paediatric Radiology (ESPR) undertook a six-stage modified Delphi process, including a detailed literature review, to create a series of consensus statements concerning patient preparation, imaging hardware and image acquisition protocols. RESULTS: One hundred and fifty-seven statements were scored for agreement by the panel of which 129 statements (82 %) achieved immediate consensus with a further 19 (12 %) achieving consensus after appropriate modification. Nine (6 %) statements were rejected as consensus could not be reached. CONCLUSIONS: These expert consensus recommendations can be used to help guide cross-sectional radiological practice for imaging the small bowel and colon. KEY POINTS: • Cross-sectional imaging is increasingly used to evaluate the bowel • Image quality is paramount to achieving high diagnostic accuracy • Guidelines concerning patient preparation and image acquisition protocols are provided.

CT imaging for prediction of complications and recurrence in acute uncomplicated diverticulitis.

PURPOSE: The first randomized clinical trial of antibiotics in uncomplicated diverticulitis (the AVOD study) showed no benefit of antibiotics. The aim of this study was to re-evaluate the computed tomography (CT) scans of the patients in the AVOD study to find out whether there were CT findings that were missed and to study whether CT signs in uncomplicated diverticulitis could predict complications or recurrence. METHODS: The CT scan images from patients included in the AVOD study were re-evaluated and graded by two independent reviewers for different signs of diverticulitis, including complications, such as extraluminal gas or the presence of an abscess. RESULTS: Of the 623 patients included in the study, 602 CT scans were obtained and re-evaluated. Forty-four (7 %) patients were found to have complications on the admitting CT scan that had been overlooked. Twenty-seven had extraluminal gas and 17 had an abscess. Four of these patients deteriorated and required surgery, but the remaining patients improved without complications. Of the 18 patients in the no-antibiotic group, in whom signs of complications on CT were overlooked, 15 recovered without antibiotics. No CT findings in patients with uncomplicated diverticulitis could predict complications or recurrence. CONCLUSION: No CT findings that could predict complications or recurrence were found. A weakness in the initial assessment of the CT scans to detect extraluminal gas and abscess was found but, despite this, the majority of patients recovered without antibiotics. This further supports the non-antibiotic strategy in uncomplicated diverticulitis.

Comparison between MRI and CT in prediction of peritoneal carcinomatosis index (PCI) in patients undergoing cytoreductive surgery in relation to the experience of the radiologist.

BACKGROUND: To compare CT and MRI for peritoneal carcinomatosis index (PCI) assessment and to compare assessments made by the radiologist based on their experiences. METHOD AND MATERIALS: MRI and CT of abdomen and pelvis were performed on 39 prospectively followed by surgery directly. Two blinded radiologists with different experience levels evaluated PCI separately on different occasions on 19 cases initially and later on the remaining 20. The agreement between the radiologists' assessment and surgical findings in total and per site were recorded. RESULTS: Total PCI: The experienced radiologist was able to assess total tumor burden correctly on both CT and MRI (kappa = 1.0). For the inexperienced radiologist the assessment was better on CT (kappa = 0.73) compared to MRI (kappa = 0.58). Different sites: The experienced radiologist showed high agreement with kappa = 0.77 for MRI and 0.80 for CT. Corresponding figures were 0.39 and 0.60 for the inexperienced radiologist. For the second phase the agreement levels increased for the inexperienced radiologist increased to 0.80 and 0.70, respectively. CONCLUSION: CT and MRI are equal when read by experienced radiologist. CT shows better results when read by an inexperienced radiologist compared to MRI, however the results of the latter can easily be improved.

Can acute abdominal CT prioritize patients with suspected diverticulitis for a subsequent clean colonic examination?

AIM: The aim of this study was to investigate whether patients with diverticulitis can be prioritized with higher urgency for a subsequent full colonic examination based upon the emergency abdominal CT scan performed at the time of presentation. METHOD: All patients with a diagnosis of diverticulitis, hospitalized during 2006 and having a CT scan on admission and a subsequent 'clean colon' examination, were reviewed. The CT scan was reviewed by two independent and blinded senior radiologists (Radiologist A and Radiologist B) for signs inconsistent with diverticulitis and suggestive of malignancy. The patients were classified on the CT scan results into group 1 (normal findings, nontumour pathology or benign polyps < 1 cm) or group 2 (benign polyps ≥ 1 cm and cancer). RESULTS: Ninety-three patients (83 in group 1 and 10 in group 2) were reviewed. Radiologist A suggested high-priority colonic examination in 18% and 50% of patients in groups 1 and 2, respectively, and Radiologist B in 63% and 90% of patients, respectively. There was a statistically significant interobserver difference, and also lower accuracy of Radiologist B compared with Radiologist A in predicting a subsequent 'clean colon' examination. CONCLUSION: Use of an emergency acute CT scan at the time of diagnosis of diverticulitis to predict a clean colon examination for neoplasia is not reliable because there is a considerable degree of interobserver difference between radiologists.

The minimum number of target lesions that need to be measured to be representative of the total number of target lesions (according to RECIST).

Response evaluation criteria in solid tumours (RECIST) were introduced as a means to classify tumour response with no definition of the minimum number of lesions. This study was conducted in order to evaluate discrepancies between full assessments based on either all target lesions or fewer lesions. RECIST evaluation was performed on separate occasions based on between one and seven of the target lesions, with simultaneous assessment of non-target lesions. 99 patients were included. 38 patients demonstrated progressive disease, in 61% of whom it was a result of the appearance of new lesions or unequivocal progress in non-target lesions. 32 patients showed stable disease, with 8 having results that differed when 1-3 target lesions were measured. 22 cases were considered as having partial regression, with only 1 case differing when performing 1-3 target lesion assessments. Seven cases demonstrated complete response. The number of discordant cases increased gradually from measuring three lesions to one target lesion. The average number of available target lesions among those with discrepancies was 7.1, which was significantly higher than those demonstrating concordance (4.1 lesions; p<0.05). In conclusion, measuring fewer than four target lesions might cause discrepancies when more than five target lesions are present.

Morphological assessment of the interface between tumor and neighboring tissues, by magnetic resonance imaging, before and after radiotherapy in patients with locally advanced rectal cancer.

BACKGROUND: Magnetic resonance imaging (MRI) in rectal cancer is sometimes performed after radiotherapy (MRI 2) to evaluate tumor response and to choose alternative forms of surgery. The accuracy of MRI 2 in distinguishing tumor delineation might be difficult due to fibrosis. PURPOSE: To evaluate the morphological changes in the interface between the tumor and neighboring organs on MRI 2 performed after radiotherapy, and to assess the accuracies of MRI before and after radiotherapy compared to histopathology after surgery. MATERIAL AND METHODS: Sixteen patients with locally advanced primary rectal cancer, with MRI before and after radiotherapy, were retrospectively studied, concerning the interface between the tumor and neighboring structures. The accuracies of MRI before and after radiotherapy were compared based on histopathology as a reference. RESULTS: The accuracies of both MRI before and after radiotherapy were moderate, with no additional value of MRI after radiotherapy compared to MRI before radiotherapy. The most predictive form of interface for involvement of a neighboring organ after radiotherapy was nodular growth of the tumor into a neighboring structure. CONCLUSION: The morphological assessment of pelvic MRI after preoperative radiotherapy does not provide any significant new information about tumor extent in patients with locally advanced rectal cancer.

Radiological findings do not support lateral residual tumour as a major cause of local recurrence of rectal cancer.

BACKGROUND: The aim of this study was to determine the sites of local recurrence following radical (R0) total mesorectal excision (TME) for rectal cancer in an effort to elucidate the reasons for recurrence. METHODS: Thirty-seven patients with recurrence following curative resection for rectal cancer were identified from a population of 880 patients operated on by surgeons trained in the TME procedure. Two radiologists independently examined 33 available computed tomograms and magnetic resonance images taken when the recurrence was detected. RESULTS: Twenty-nine of the 33 recurrences were found in the lower two-thirds of the pelvis. Two recurrent tumours appeared to originate from lateral pelvic lymph nodes. Evidence of residual mesorectal fat was identified in 15 patients. Fourteen of the recurrent tumours originated from primary tumours in the upper rectum; all of these tumours recurred at the anastomosis and 12 of the 14 patients had evidence of residual mesorectal fat. CONCLUSION: Lateral pelvic lymph node metastases are not a major cause of local recurrence after TME. Partial mesorectal excision may be associated with an increased risk of local recurrence from tumours in the upper rectum.

Non-Hodgkin's lymphoma in McKusick syndrome. A case report.

The McKusick syndrome in a female who developed highly malignant lymphoma at the age of 23, with multiple parenchymal lesions involving both kidneys, the lungs and the pancreas and also splenomegaly but without lymphadenopathy, is described together with diagnostic imaging findings. McKusick syndrome is associated with impaired cell-mediated immunity and might, like several other similar syndromes, harbor an increased risk of certain types of lymphoma. To our knowledge, there are no previous reports of non-Hodgkin's lymphoma in a patient with McKusick syndrome. The increased incidence of lymphoma in certain cases of congenital immunodeficiency raises the issue of a possible relationship between McKusick syndrome and lymphoma and could perhaps serve as one of the primary steps for a further characterization of this syndrome.