The rationale for performing MR imaging before surgery for primary hyperparathyroidism.

OBJECTIVE: The purpose of this study was to evaluate prospectively Magnetic Resonance Imaging (MRI) for the preoperative localization of hyperfunctioning parathyroid glands. DESIGN: Prospective study of 58 consecutive patients with biochemically confirmed primary hyperparathyroidism who underwent preoperative MRI. SETTING: The setting is a referral centre. PATIENTS: Fifty-six of the 58 consecutive patients (41 women, 17 men) were studied by both preoperative MRI and 99mTC MIBI scintigraphy, and two by MRI alone. The same surgeon, using the information from both MRI and 99mTC MIBI, performed surgery in 58 patients, including 19 with a history of neck surgery. Initial interpretation of each MR study was done independently by one radiologist and the surgeon and then results were compared. At surgery, the operative duration, the precise anatomical location, weight, and dimensions as well as complete histopathological evaluations of all excised glands were recorded. MAIN OUTCOME MEASURE: In addition to the prospective assessment of MRI, this study compared performance of MRI with double-phase 99mTC MIBI scintigraphy for preoperative localization of hyperfunctioning parathyroid glands. RESULTS: All patients became normocalcaemic after surgery. MRI and 99mTC MIBI imaging revealed 53 of 58 (91%) and 47 of 56 (84%) of abnormal glands, respectively. Sensitivities of MRI and 99mTC MIBI were respectively 94.3 and 88.0. Positive predictive values were 96.15 and 93.60. When MRI and 99mTC MIBI were interpreted together, the sensitivity and positive predictive values both raised to 98.10. Median operative duration was 30 minutes (ranges 20-300 minutes, mean 65). CONCLUSION: MRI has better sensitivity and positive predictive value than 99mTC MIBI scintigraphy for the detection of hyperfunctioning parathyroid glands. The combination of the two studies provides an additional increase in sensitivity and positive predictive value leading to a more precise anatomical localization of the abnormal parathyroid glands reducing both the extent of the surgical dissection and the operative duration.

Bilateral adrenal lymphoma with Addison's disease : a surgical pitfall.

A 65 year old man presenting with abdominal and back pain was found to have bilateral adrenal masses. Phaeochromocytomas were initially suspected on the basis of increased catecholamine excretion. This diagnosis seemed unlikely in view of clinical findings and a negative 123I-metaiodobenzylguanidine scintigraphy. A biopsy of the right adrenal mass revealed a diagnosis of primary adrenal B-cell lymphoma. Hyponatraemia and subtle clinical signs of adrenal insufficiency led to a diagnosis of Addison's disease, a common complication of primary adrenal lymphoma. Thus, bilateral adrenal masses associated with Addison's disease should raise the suspicion of possible primary adrenal lymphoma.

Is a lung perfusion scan obtained by using single photon emission computed tomography able to improve the radionuclide diagnosis of pulmonary embolism?

Planar pulmonary scintigraphy is still regularly performed for the evaluation of pulmonary embolism (PE). However, only about 50-80% of cases can be resolved by this approach. This study evaluates the ability of tomographic acquisition (single photon emission computed tomography, SPECT) of the perfusion scan to improve the radionuclide diagnosis of PE. One hundred and fourteen consecutive patients with a suspicion of PE underwent planar and SPECT lung perfusion scans as well as planar ventilation scans. The final diagnosis was obtained by using an algorithm, including D-dimer measurement, leg ultrasonography, a V/Q scan and chest spiral computed tomography, as well as the patient outcome. A planar perfusion scan was considered positive for PE in the presence of one or more wedge shaped defect, while SPECT was considered positive with one or more wedge shaped defect with sharp borders, three-plane visualization, whatever the photopenia. A definite diagnosis was achieved in 70 patients. After exclusion of four 'non-diagnostic' SPECT images, the prevalence of PE was 23% (n =15). Intraobserver and interobserver reproducibilities were 91%/94% and 79%/88% for planar/SPECT images, respectively. The sensitivities for PE diagnosis were similar for planar and SPECT perfusion scans (80%), whereas SPECT had a higher specificity (96% vs 78%; P =0.01). SPECT correctly classified 8/9 intermediate and 31/32 low probability V/Q scans as negative. It is concluded that lung perfusion SPECT is readily performed and reproducible. A negative study eliminates the need for a combined V/Q study and most of the 'non-diagnostic' V/Q probabilities can be solved with a perfusion image obtained by using tomography.

Intestinal involvement in Buerger's disease.

Thromboangiitis obliterans characteristically affects small- and medium-sized vessels of the limbs in young smokers. There is some controversy about the existence of visceral localizations of the disease. The case of a patient with a well-established diagnosis of thromboangiitis obliterans who presented with mesenteric ischemia is described and the literature concerning mesenteric involvement in the disease is reviewed.

Usefulness of [99mTC]MIBI and [18F]fluorodeoxyglucose for imaging recurrent medullary thyroid cancer and hyperparathyroidism in MEN 2a syndrome.

We report the case of a MEN 2a patient with a history of medullary thyroid cancer (MTC) treated by total thyroidectomy, who presented an increasing calcitonin level, suggesting tumor recurrence. Conventional radiographic and radionuclide imaging failed to localize the responsible lesions. A planar and tomographic (SPECT) [99mTc]MIBI scan, performed in order to investigate a recent hyperparathyroidism localized a parathyroid adenoma and revealed an abnormal uptake in the left lateral neck region, corresponding to apparently banal lymph nodes on MRI. This abnormal uptake was also observed on a [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) study and was proven to be an uptake in MTC lymph nodes metastases as confirmed by histopathologic analysis. We conclude that, using an adequate acquisition protocol (i.e. SPECT), [99mTc]MIBI scan is potentially able to localize both parathyroid adenoma and recurrent MTC at one and the same time, particularly in case of non-diagnostic conventional imaging techniques. In this setting, the potential usefulness of FDG-PET is also discussed.

Focal nodular hyperplasia: natural course observed with CT and MRI.

PURPOSE: The purpose of this work was to assess the natural course of biopsy-proven focal nodular hyperplasia (FNH). METHOD: Eighteen biopsy-proven FNHs in 14 patients (12 women and 2 men) who were followed for at least 6 months with CT and/or MRI were included in the study. The volume of the lesions was calculated twice by two observers using the summation of areas method. Intra- and interobserver variability was assessed by intraclass correlation coefficients. Longitudinal data analysis was performed with generalized estimating equations. RESULTS: The volume of FNH was stable in 6 cases, decreased in 10 cases, and increased in 2 cases. Intra- and interobserver variability in size measurements was 5-10%. Intraclass correlation coefficients were >0.992. Longitudinal data analysis showed that there was a general trend of lesion regression. CONCLUSION: Long-term follow-up and objective measurements performed in patients with biopsy-proven lesions show that the natural course of FNH is variable. In particular, lesion regression is not rare.

Oesophageal self expanding metal stents. Preliminary report about covered and non-covered types.

OBJECTIVE: The aim of this study was to evaluate the effectiveness and complications rate of covered and non-covered self expanding metal stents in the palliative treatment of oesophageal dysphagia. DESIGN: In this retrospective non-randomized study, we evaluated 11 non-covered and 17 covered stents of different types. RESULTS: Grade of dysphagia and improvement after treatment were similar in both groups, all the seven fistulas were sealed by covered stents. Covered stents seem to be safer regarding the rate of life-threatening complications and reinterventions. In contrast to published studies, bleeding was our major complication with death related in half of these patients. Aorto-Oesophageal fistula was proved by autopsy in two of them. CONCLUSIONS: Covered stents lead to less drawbacks than non-covered ones and seem to be recommended in the palliation of oesophageal dysphagia even in the absence of fistula.

[Radiation exposure and computed tomography]. / Irradiation en tomodensitométrie thoracique.

Computed Tomography (CT) is recognized as a relatively high-dose diagnostic procedure. There is some obscurity in the literature about the doses due to conventional CT, spiral CT and High Resolution Computed Tomography (HRCT) of the chest. Conventional chest CT results in a radiation dose approximately 100 times that of a standard chest film and 10 times that of a mammography; on the other hand, conventional chest CT is safe for the lens and the pelvis (ovaries, testes and uterus). Radiation dose associated with helical CT is potentially lower than the dose associated with conventional CT. HRCT, consisting of 1- to 2- mm thick-sections performed at 10 mm intervals, has an effective radiation dose lower than that of conventional CT, even with high-dose techniques (400 mAs). HRCT scans obtained at reduced milliamperage (40-80 mAs), the so-called "low-dose HRCT technique", may provide satisfactory visualization of lung parenchyma in the majority of cases and is recommended in patients in whom radiation dose is a major concern (pediatric population or young women in order to minimize breast irradiation). The awareness of radiation dose will become increasingly important for both referring physicians and radiologists when determining indications and deciding which types of imaging procedures and specific protocols should be used.

MR imaging of hypervascular liver tumors: timing optimization during the arterial phase.

To analyze the optimal timing strategy for the detection of hypervascular liver tumors during the arterial phase of magnetic resonance (MR) imaging, a test examination after injection of 2 mL of gadopentetate dimeglumine was performed in 47 patients. The time course of the tumor-to-liver contrast-to-noise ratio (CNR) for all studies together was determined relative to the start of injection, the time of peak aortic enhancement, and the time of peak enhancement in the tumor. All studies were grouped together and the highest CNR was transiently observed at the time of peak tumor enhancement. This CNR was significantly higher than those observed at fixed delays after peak aortic enhancement. However, the CNRs at peak tumor enhancement+/-1.5 seconds did not differ significantly from those obtained after peak aortic enhancement. Finally, the CNRs obtained at fixed delays after the start of injection remained significantly lower. In hypervascular liver tumors, a higher CNR can be obtained during the arterial phase when the MR imaging delay is determined relative to the time of peak enhancement in the tumor or the aorta rather than being fixed after the start of contrast material injection. Timing based on the enhancement profile in the tumor rather than in the aorta should be performed only if rapid MR imaging is available with a time resolution of about 1.5 seconds to image the whole liver.

Mesenterico-left intrahepatic portal vein shunt: original technique to treat symptomatic extrahepatic portal hypertension.

UNLABELLED: MESENTERICO-LEFT INTRAHEPATIC PORTAL VEIN SHUNT: Original technique to treat symptomatic extrahepatic portal hypertension. OBJECTIVE: Revascularization of the intrahepatic portal system as decompressive surgery for chronic extrahepatic portal hypertension. SUMMARY BACKGROUND DATA: In patients with extrahepatic portal hypertension (portal trunk thrombosis in presence of a normal liver), shunt surgery is indicated when patient is bleeding from varices at a site not accessible for the endoscopist. Although surgical portal decompression is an efficient procedure, there is a risk of depriving the liver from the splanchnic venous flow and a risk of developing porto-systemic shunt related side effects. METHOD: A shunt was created between the superior mesenteric vein and the umbilical portion of the left portal vein. This technique allows to bypass the thrombosed portion of the portal vein but avoiding dissection of the cavernoma in the liver hilum and related risk of intraoperative hemorrhage. RESULTS: The procedure was successfully performed in one adult patient considered unshuntable in view of classic surgical procedures and in whom sclerotherapy was unsuccessful. This operation achieved an effective decompression of the splanchnic venous system. CONCLUSION: Rerouting the venous splanchnic flow through the liver was possible. It had the major physiological advantage of restoring the normal hepatic vascularization. It also avoided putting the patient at risk of developing porto-systemic shunt related side effects. This option should be considered when shunt procedures are indicated in patients with extrahepatic portal hypertension.

Congenital anomalies of the inferior vena cava and left renal vein: evaluation with spiral CT.

PURPOSE: To determine with spiral computed tomography (CT) the incidence and caval location of left renal vein (LRV) variants that may affect inferior vena cava (IVC) filter placement, spermatic vein embolization, and adrenal or renal venous sampling. MATERIALS AND METHODS: Contrast material-enhanced spiral CT scans of 1,014 patients were evaluated for the incidence and configuration of LRV variants and for the distribution of the entrances of these veins into the IVC. RESULTS: In this series, variants detected were as follows: one azygos continuation of the IVC (0.1%), three bilateral IVCs (0.3%), and 102 LRV variants (10%) including 38 retroaortic renal veins (3.7%) and 64 circumaortic venous rings (6.3%). In the retroaortic renal vein group, the distance between the entrance of the LRV into the IVC and the confluence of the iliac veins was +62.5 mm +/- 8.7. In the circumaortic venous ring group, the distance between the entrances of the retroaortic and preaortic limbs into the IVC was -39.0 mm +/- 17.4; the distance between the entrance of the left retroaortic limb into the IVC and the confluence of the iliac veins was +63.2 mm +/- 17.1. CONCLUSIONS: Detailed knowledge of these anomalies is crucial for IVC filter placement, spermatic vein embolization, and adrenal or renal venous sampling.

Inflammatory pseudotumor of the liver: MRI with mangafodipir trisodium.

Inflammatory pseudotumor of the liver is a rare benign mass that is often misdiagnosed as hepatocellular carcinoma at preoperative imaging. We report a case of inflammatory pseudotumor of the liver with special emphasis on the appearance at MRI after administration of mangafodipir trisodium. On T1-weighted images the lesion was slightly hypointense relative to the liver, and on T2-weighted images it was isointense with a hyperintense capsule. No tumor enhancement was seen on T1-weighted images after administration of mangafodipir trisodium. MRI with mangafodipir trisodium might help to distinguish inflammatory pseudotumor of the liver from hepatocellular carcinoma.

[Mesenteric and portal venous gas in infarction of the small intestine in adults. Apropos of 3 clinical cases. Value of x-ray computed tomography]. / L'aéromésentérie et l'aéroportie dans l'infarctus du grêle chez l'adulte. A propos de trois cas cliniques. Intérêt de la tomodensitométrie.

Three case reports are presented with mesenteric and portal venous gas secondary to mesenteric infarction. In these patients with ileus, abdominal CT Scan appears as the most reliable diagnosis procedure. It can detect intravascular gas but also abnormalities of the intestinal wall such as intramural gas even without contrast. In mesenteric infarction, mesenteric and portal venous gas are radiological signs which considerably worsen the prognosis.

Spiral computed tomography with three-dimensional reconstructions for severe blunt abdominal traumas: a useful complementary tool?

Spiral computed tomography (CT) has proved to be a valuable tool by providing three-dimensional (3D) images of the studied structures. We hypothesized that a more realistic depiction of lesions by 3D CT could be of interest for surgeons who are treating blunt abdominal traumas and lead to less inappropriate triage. A good working relationship between surgeons and radiologists allowed us to perform a 3D CT examination in six patients. In the first patient, the 3D CT accurately demonstrated spleen fragmentation without devascularized fragment. The second patient had complete devascularization of the spleen upper pole. Conservative treatment was pursued for both patients. For the third patient, 3D CT helped us to differentiate peritoneal-perisplenic fluid from subcapsular fluid. The fourth patient had minor spleen injury associated with severe lacerations of the left kidney. 3D CT showed a complete separation of the kidney lower pole. A delayed partial lower nephrectomy was performed. The fifth patient presented a fragmented spleen and transient massive haematuria related to a well-contained laceration of the kidney upper pole that were amenable to nonoperative management. The sixth patient was emergency operated for active bleeding from a fragmented spleen. 3D CT performed 2 months after spleen repair allowed the assessment of the amount of devascularized tissue, as well as the status of the upper abdomen arteries. For haemodynamically stable patients, 3D CT could be a helpful addition to conventional axial CT for quantifying blunt abdominal traumas, for making the choice between nonoperative and operative treatment, but also between emergency and delayed surgical strategy.

Detection and segmental location of malignant hepatic tumors: comparison of ferumoxides-enhanced gradient-echo and T2-weighted spin-echo MR imaging.

OBJECTIVE: The aim of our prospective study was to compare the values of ferumoxides-enhanced gradient-echo and T2-weighted spin-echo MR imaging for the detection and segmental location of malignant hepatic tumors. SUBJECTS AND METHODS: Eighteen patients underwent ferumoxides-enhanced T2 weighted spin-echo and steady-state gradient-echo imaging before surgery. Intraoperative sonography was used as the reference examination and showed 28 malignant tumors involving 39 of the 144 hepatic segments. The MR images were reviewed independently by two observers who recorded the number of tumors and their segmental location. The results of the segmental location were subjected to receiver-operating-characteristic analysis. Tumor-liver, vessel-liver, and tumor-vessel contrast-to-noise ratios were calculated. RESULTS: Detection on the gradient-echo images did not differ significantly from that on the T2-weighted spin-echo MR images (observers A and B detected 23 and 24 tumors, respectively, on the gradient-echo images; the two observers each detected 22 tumors on the T2-weighted spin-echo images). Segmental localization was significantly better on the gradient-echo images than on the T2-weighted spin-echo images (mean area under the receiver-operating-characteristic curve: 0.974 versus 0.895 for observer A and 0.962 versus 0.906 for observer B, p = .024). The highest contrast-to-noise ratios for vessel to liver and tumor to vessel were obtained on the gradient-echo images and the highest tumor-liver contrast-to-noise ratio was obtained on the T2-weighted spin-echo images. CONCLUSION: In our study, ferumoxides-enhanced gradient-echo imaging was as accurate as T2-weighted spin-echo imaging for revealing malignant hepatic tumors and was superior for showing their segmental location.

Venous return by the paraumbilical and hepatic veins in case of superior vena cava obstruction.

Pseudolesion in segment IV of the liver is a well-known diagnostic pitfall during arterial portography or even spiral computed tomography (CT) of the liver. It has suggested that this pseudolesion is the result of an abnormality in subsegmental perfusion. We report a case of an early dense contrast enhancement of segment IV of the liver by epigastric and paraumbilical veins in a patient with a superior vena cava obstruction. A pseudolesion in segment IV was observed in this patient on a spiral CT of the liver obtained during the portal phase.

Blunt renal traumas: contribution of spiral CT with three dimensional reconstruction to the surgical decision process?

Spiral CT has proved to be a valuable tool by providing various kinds of three-dimensional (3D) images of the studied structures. Such 3D images, which offer a more realistic depiction of the lesions, could be of interest for surgeons who are attempting to treat conservatively blunt abdominal traumas and lead to less inappropriate triage between conservative and operative management particularly for renal trauma. A good working relationship between surgeons and radiologists allowed us to perform an early follow-up 3D spiral CT on a commercially available spiral CT scanner. In the first adult patient, the 3D CT demonstrated minor spleen injury associated with severe lacerations of the left kidney with complete separation of the kidney lower pole. A delayed partial lower nephrectomy was performed. For the second 12-year-old patient presenting with severe spleen trauma and macroscopic hematuria, the 3D CT accurately documented the spleen and renal lesions that were safely amenable to nonoperative treatment. For hemodynamically stable patients, 3D CT is a potentially helpful addition to conventional axial CT for quantifying blunt renal traumas and for making the strategic choice between nonoperative, emergency or delayed surgical treatment.

3D spiral CT of the tracheobronchial tree.

OBJECTIVE: Because of intrinsic limitations of transverse cross-sectional imaging methods, CT sometimes is insufficient for adequate evaluation of complex tracheobronchial anomalies. This article describes a complementary 3D procedure specifically dedicated to the study of the tracheobronchial tree. MATERIALS AND METHODS: The procedure combines a specific spiral CT acquisition with 2 or 4 mm collimation, 3D surface rendering of the tracheobronchial aerial content, and double obliquity multiplanar reformats directly planned on the 3D virtual object. It was performed in 11 complex cases including 3 stented benign or malignant stenoses and 2 single lung transplantations. RESULTS: Easier understanding of the tracheobronchial status was achieved in all cases. In three cases, the procedure yielded relevant diagnostic information that neither fiberoptic endoscopy nor transverse CT had provided, leading to significant modification of patient management. CONCLUSION: Three-dimensional spiral CT of the bronchial tree with secondary reformation seems suitable in clinical practice for selected cases.

[Spiral CT of the bile ducts]. / La TDM spiralée des voies biliaires.

The multiplanar capability of spiral CT improves the evaluation of bile duct lesions. In particular, spiral CT after intravenous administration of a cholangiographic agent (spiral CT cholangiography) provides adequate 2D and 3D images of the bile ducts in patients with normal bilirubin levels. Spiral CT cholangiography may be particularly useful as a noninvasive imaging method to detect biliary anatomic variations and bile duct stones before or after laparoscopic cholecystectomy. This technique does not replace retrograde cholangiography which has therapeutic applications, but might help to select patients who need to undergo invasive procedures such as retrograde cholangiography.