Quantification of calcium burden by coronary CT angiography compared to optical coherence tomography.

Coronary artery calcifications (CAC) are frequently observed in patients referred for coronary CT angiography (CTA). Calcification volume (in mm3) can accurately be assessed during catheterization by optical coherence tomography (OCT). The aim of the present study was to investigate the accuracy of CTA-derived assessment of calcification volume as compared with OCT. 66 calcified plaques (32 vessels) from 31 patients undergoing OCT-guided PCI with coronary CT acquired as a standard of care were included. Coronary CT and OCT images were matched using fiduciary points. Calcified plaques were reconstructed in three dimensions to calculate calcium volume. A Passing-Bablok regression analysis and the Bland-Altman method were used to assess the agreement between imaging modalities. Twenty-seven left anterior descending arteries and 5 right coronary arteries were analyzed. Median calcium volume by CTA and OCT were 18.23 mm3 [IQR 8.09, 36.48] and 10.03 mm3 [IQR 3.6, 22.88] respectively; the Passing-Bablok analysis showed a proportional without a systematic difference (Coefficient A 0.08, 95% CI - 1.37 to 1.21, Coefficient B 1.61, 95% CI 1.45 to 1.84) and the mean difference was 9.69 mm3 (LOA - 10.2 to 29.6 mm3). No differences were observed for minimal lumen area (Coefficient A 0.07, 95% CI - 0.46 to 0.15, Coefficient B 0.85, 95% CI 0.64 to 1.2). CTA volumetric calcium evaluation overestimates calcium volume by 60% compared to OCT. This may allow for an appropriate interpretation of calcific burden in the non-invasive setting. Even in presence of calcific plaques, a good agreement in the MLA assessment was found. Coronary CT may emerge as a tool to quantify calcium burden for invasive procedural planning.

Additional value of whole-body positron emission tomography with fluorine-18-2-fluoro-2-deoxy-D-glucose in recurrent colorectal cancer.

PURPOSE: To assess the additional value of the whole-body [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) scan as a staging modality complementing conventional diagnostic methods (CDM) in patients suspected of having recurrent colorectal adenocarcinoma. PATIENTS AND METHODS: In 103 patients, the discordances between FDG-PET and CDM results were identified and related to the final diagnosis obtained by histopathology or clinical follow-up (> 1 year). All FDG-PET studies were reviewed with full knowledge of the CDM findings. RESULTS: In a region-based analysis, discordances between CDM and FDG-PET findings were found in 40 of 412 regions (10%). In these, FDG-PET had additional diagnostic value in 14 of 16 locoregional, six of seven hepatic, seven of eight abdominal, and eight of nine extra-abdominal regions. In a patient-based analysis, CDM categorized a subgroup of 60 patients as having resectable recurrent disease limited to the liver (n = 37) or locoregional region (n = 23). In 13 of these patients, there were discordant FDG-PET findings, detecting additional tumor sites in nine patients and excluding disease in three patients and yielding an additional diagnostic value in 20% of the patients. A second subgroup consisted of 13 patients with inconclusive CDM findings (n = 5) or with elevated plasma carcinoembryonic antigen levels and an otherwise negative conventional work-up (n = 8). In these patients, FDG-PET results were correct in eight of nine discordances, yielding a positive additional diagnostic value in 62% of the patients. CONCLUSION: Whole-body FDG-PET can have a clear impact on the therapeutic management in the follow-up of patients with colorectal cancer.

A pancreatic mucinous cystadenoma in a man with mesenchymal stroma, expressing oestrogen and progesterone receptors.

A 43-year-old man presented with abdominal discomfort caused by relapsing pancreatitis. Radiological examination revealed a multilocular cystic mass in the tail of the pancreas, which was resected. Gross examination showed a multilocular cystic lesion measuring 2.5 cm in diameter and containing clear fluid. Microscopically, a mucinous cystadenoma with mesenchymal stroma was diagnosed. The lesion showed two different components: a cyst lined by a columnar, mucin-secreting epithelium and a moderate cellular stroma composed of spindle cells. The stromal element appeared similar to primitive mesenchyme. Immunohistochemical staining confirmed this origin through vimentin expression and showed moderate to strong nuclear staining with oestrogen and progesterone receptor antibodies. Cystadenomas are rare tumours of the pancreas, but mesenchymal stroma is uncommon in such tumours; it is more frequently described in the liver and the bile ducts, and primarily in women.

Gastroepiploic artery coronary bypass graft: non-invasive patency evaluation using color and duplex Doppler ultrasonography.

OBJECTIVE: Color and duplex Doppler ultrasound and digital subtraction angiography were compared for the evaluation of graft patency of the gastroepiploic artery (GEA). METHODS: In 77 observations, ultrasound and digital subtraction angiography were compared. The coronary resistance index (cRI) was defined as the maximal systolic flow velocity minus the maximal diastolic flow velocity, divided by the maximal systolic flow velocity. On digital subtraction angiography, the graft was considered patent, occluded, or patent but non-functional. Grafts were defined as non-functional when they had a diameter of less than 5F with the absence of opacification of the native coronary artery. RESULTS: Of the 77 observations, 64 GEAs were patent angiographically, three were occluded and ten grafts were considered as patent but non-functional. Using color and duplex ultrasound, the GEA was identified in 65 out of 77 observations. There were no cases of false positive visualization of the GEA. All sonographically detected non-functional grafts (n = 7) had a cRI of greater than 0.60. When the non-visualized grafts are considered either non-functional or occluded, a cut-off value for a cRI of 0.60 results in a sensitivity and specificity of 100 and 75%, respectively. CONCLUSION: We propose ultrasound as a primary screening tool for evaluating graft patency. While color Doppler is a suitable technique for graft visualization, spectral analysis with the calculation of a cRI is required for functional evaluation.

Case report: pseudotumoral pelvic retroperitoneal fibrosis associated with orbital fibrosis.

We report the case of a man with bilateral orbital fibrous pseudotumours and a large pelvic mass which was initially thought to be malignant. Sonographically guided transrectal core biopsies showed it to be a fibrotic retroperitoneal pseudotumour. The mass decreased after steroid therapy. The computed tomography and magnetic resonance imaging features of this unusual form of pelvic fibrosis as well as the association with heterotopic fibrosis are discussed.

Three-dimensional imaging of acetabular dysplasia: diagnostic value and impact on surgical type classification.

OBJECTIVE: To investigate the diagnostic value and the impact on surgical type classification of three-dimensional (3D) images for pre-surgical evaluation of dysplastic hips. MATERIALS AND METHODS: Three children with a different surgical type of hip dysplasia were investigated with helical computed tomography. For each patient, two-dimensional (2D) images, 3D, and a stereolithographic model of the dysplastic hip were generated. In two separate sessions, 40 medical observers independently analyzed the 2D images (session 1), the 2D and 3D images (session 2), and tried to identify the corresponding stereolithographic hip model. The influence of both image presentation (2D versus 3D images) and observer (degree of experience, radiologist versus orthopedic surgeon) were statistically analyzed. The SL model choice reflected the impact on surgical type classification. RESULTS: Image presentation was a significant factor whereas the individual observer was not. Three-dimensional images scored significantly better than 2D images (P=0.0003). Three-dimensional imaging increased the correct surgical type classification by 35%. CONCLUSION: Three-dimensional images significantly improve the pre-surgical diagnostic assessment and surgical type classification of dysplastic hips.

Diagnostic value of 99Tcm-d,l-HMPAO-labelled leukocyte scintigraphy in the detection of vascular graft infections.

Prosthetic vascular graft infection is a relatively uncommon complication of peripheral vascular surgery. We retrospectively analysed technetium-99m-d,l-hexamethylpropylene amine oxime (99Tcm-d,l-HMPAO) labelled leukocyte scans of 21 patients with a suspected vascular graft infection. Operative findings, bacteriological cultures, radiological findings or clinical follow-up were used to confirm the diagnosis. We found eight true-positive and six true-negative cases. There were no false-positive scintigraphic diagnoses. The false-negative rate was 33% (n = 7). Our results show a sensitivity of 53%, a specificity of 100% and an accuracy of 66%. The conclusion is that a negative 99Tcm-d,l-HMPAO-labelled leukocyte scan is of limited value in ruling out a vascular graft infection. A combination of computed tomography (CT-scan) and a 99Tcm-d,l-HMPAO-labelled leukocyte scan is probably the most efficient way of diagnosing a vascular graft infection.

Effectiveness of imaging studies in acute appendicitis: a simplified decision model.

Computed tomography (CT) and ultrasonography (US) have been proposed as non-invasive diagnostic aids in patients with suspected acute appendicitis. Currently, clear guidelines about the indications to use these techniques are lacking. Using the concepts of decision analysis, a model was created to calculate the effectiveness of US and CT in patients with clinically suspected appendicitis. The perspective chosen was the health of individual patients. The model makes use of published data and provides a critical threshold probability (ctp). Decisions in individual cases can be made by comparing ctp with the clinical probability of disease. The calculated ctp-values for US and CT were 0.58 and 0.74, respectively. In other words, on average, US (CT) is indicated only if the expert clinician considers the probability of disease to be smaller than 58% (74%). It is concluded that in patients with suspected acute appendicitis, selective rather than routine use of imaging studies is recommended. The exact value of the decision threshold should be determined in function of the local situation.

Intraperitoneal contrast material combined with CT for detection of peritoneal metastases of ovarian cancer.

OBJECTIVE: To determine the sensitivity and specificity of CT-peritoneography (CT-P) in detecting peritoneal carcinomatosis in primary or recurrent ovarian cancer. METHODS: Twenty-five patients were submitted to a standard abdominal CT (CT) as well as a computed tomography after intraperitoneal infusion of contrast material (CT-P). Twenty patients had ovarian masses clinically suspected to be malignant. In five patients with ovarian cancer who underwent prior debulking surgery, recurrent disease was suspected. RESULTS: In 21/25 patients an ovarian malignancy was histologically confirmed. During surgery peritoneal spread was found in 13 patients; only in 5 cases CT correctly suggested peritoneal metastases (sensitivity 38%). However, in 10/13 women CT-P indicated peritoneal spread, increasing the overall sensitivity from 38% to 77%. Sensitivity varied substantially according to the different abdominal areas, and was lowest in the left subphrenic space (25%). The sensitivity of CT-P was 71% and 72% in the right paracolic gutter and the pelvis, respectively. Sensitivity of CT-P was not found to be size-dependent, but was mainly related to the morphology of the lesions, with 100% sensitivity in nodular lesions, and only 21% sensitivity for flat peritoneal lesions. CT-P did not improve detection of omental metastases, and was not advantageous when ascites was present. Previous surgery reduced overall specificity from 80% to 57%. CONCLUSION: CT-P greatly improved the sensitivity of CT in the preoperative detection of peritoneal spread of ovarian malignancy. However, the technique failed to detect flat peritoneal metastases, and had a low specificity in patients with a history of prior abdominal surgery.

Diagnostic accuracy of ultrasonography and surgical decision-making in patients referred for suspicion of appendicitis.

Two groups of patients referred for suspicion of acute appendicitis were compared to evaluate the accuracy of preoperative ultrasonography (US) and surgical decision-making. In one retrospective study, US was performed by trainees using a 3.5 MHz probe (219 patients). In the second prospective study, US was performed by a resident radiologist using a 5 MHz probe (144 patients). US accuracy rose from 65% to 90%, especially due to an improved negative predictive value (from 52% to 92%). The positive predictive value of US was 89%. The sonographically adjusted clinical decision to operate was correct in 85%. Thus, all patients with positive US should be operated. In contrast, clinical judgment must prevail in case of negative US findings in order to prevent surgical delay in about 11%. The negative laparotomy rate decreased by 5% only. This is probably due to the limited influence of negative US findings on surgical decision. US is to be recommended in all patients suspected for acute appendicitis when performed with an appropriate probe by an experienced ultrasonographist. However, it may not, on it self, reduce the rate of unnecessary operative procedures.

Delayed remote abscess formation after spillage of infected gallstone during laparoscopic cholecystectomy: CT and US findings.

We report on a patient who presented an abdominal wall abscess two years after percutaneous cholecystectomy. The diagnosis of wall abscess caused by migrating gallstones could be made sonographically, whereas thin-section spiral CT failed to show the cause of the abscess: a non-calcified gallstone.

[Spiral CT angiography]. / Spiraal CT angiografie.

Spiral CT angiography (CTA) is a promising technique for the evaluation of vascular lesions. We review some important technical aspects in CTA such as longitudinal resolution, determination of injection scan interval and limitations of three-dimensional rendering techniques. Several current and potential applications are discussed.

[Spiral CT of the liver: detection of focal liver lesions]. / Spiraal CT van de lever: detectie van focale leverletsels.

The advantages of spiral CT mainly reside in the possibility to scan the entire liver volume in a single period of about 20 to 30 seconds, while the patient holds his breath. This high acquisition speed allows to selectively evaluate the entire liver during the arterial and/or portal venous phase. In addition, spiral CT is a true volumetric technique that allows a posteriori calculation of perfectly contiguous or even overlapping slices. These two specifications, high acquisition speed and the absence of data gaps improves the detection of focal liver lesions.

[Spiral CT of the pancreas]. / Spiraal CT van het pancreas.

Spiral CT allows rapid acquisition of axial images during a single breath-hold. This results in optimal vascular and parenchymal opacification and eliminates respiratory misregistration. These factors also contribute to high quality multiplanar displays. Double phase spiral CT allows repeated scanning in the vascular (arterial) phase and in the parenchymal phase after contrast injection, resulting in optimal detection of parenchymal as well as vascular lesions. The advantages and applications of spiral scanning for imaging the pancreas are discussed.

Large polypoid gastric leiomyoma with intermittent duodenal prolapse.

A case of large pedunculated gastric leiomyoma with intermittent prolapse into the duodenum, causing a somewhat confusing clinical picture is presented. Ultrasound-, CT- and barium studies clearly showed the origin and extent of the tumor. Sonography was the only imaging method that showed intermittent prolapse of the tumor during examination. Imaging studies did not allow prediction of the benign nature of the tumor.

Torsion of accessory spleen in an adult patient: imaging findings at CT, MRI and angiography.

A 40-year-old woman presented with acute left upper quadrant pain due to torsion of an accessory spleen around its long vascular pedicle, causing infarction. Torsion of an accessory spleen is extremely rare. As far as we known only 14 cases have previously been reported in the literature, and more than half patients were children. MRI can be helpful in the differential diagnosis of infarction by suggesting haemorrhagic necrosis on the T2-weighted images.

Benign mesenteric schwannoma: MRI findings.

Accurate differentiation of retro- or intraperitoneal localization of a primary abdominal tumor by US and CT is often difficult. In our case an abdominal mass was incidentally discovered and identified as a typical benign schwannoma, but with a very atypical location in the mesentery. We found that MRI was a valuable adjunct to CT for exact tumor localization.

Osler-Rendu-Weber with liver involvement.

Osler-Rendu-Weber disease, or hereditary hemorrhagic telangiectasia, is a vascular disease with autosomal dominant transmission. The liver is involved in 31% of patients with hereditary hemorrhagic telangiectasia (1). It appears that the lesions uncommonly causes serious disease. We report the imaging findings and the therapy in a case with extensive telangiectasis in the liver.

Pancreatic involvement in systemic sarcoidosis: CT findings.

Sarcoidosis of the pancreas is a rare entity. We report on the computed tomographic demonstration of multifocal pancreatic involvement in a patient with systemic sarcoidosis.