Nadir Ghanem

18F-DOPA positron emission tomography for tumour detection in patients with medullary thyroid carcinoma and elevated calcitonin levels

Abstract. In spite of the availability of numerous procedures, diagnostic imaging of tumour manifestations in patients with medullary thyroid carcinoma and elevated calcitonin levels is often difficult. In the present study, the new procedure of fluorine-18 dihydroxyphenylalanine positron emission tomography (18F-DOPA PET) was compared with the established functional and morphological imaging methods. After evaluation of the normal distribution of 18F-DOPA, 11 patients with medullary thyroid carcinoma were examined using 18F-DOPA PET. Results of 18F-fluorodeoxyglucose (18F-FDG) PET, somatostatin receptor scintigraphy (SRS) and morphological tomographic imaging (CT/MRI) were available for all patients. All individual procedures were evaluated without reference to prior information. Data assessment for each patient was based on cooperation between experienced radiologists and specialists in nuclear medicine, who considered all the available findings (histological results, imaging, follow-up studies). This cooperation served as the gold standard against which the results of the individual procedures were evaluated. A total of 27 tumours were studied [three primary tumours (PT)/local recurrence (LR), 16 lymph node metastases (LNM) and eight organ metastases (OM)]. 18F-DOPA PET produced 17 true-positive findings (2 PT/LR, 14 LNM, 1 OM), 18F-FDG PET 12 (2 PT/LR, 7 LNM, 3 OM), SRS 14 (2 PT/LR, 8 LNM, 4 OM) and morphological imaging 22 (3 PT/LR, 11 LNM, 8 OM). The following sensitivities were calculated with respect to total tumour manifestations: 18F-DOPA PET 63%, 18F-FDG PET 44%, SRS 52%, morphological imaging 81%. Thus, the morphological imaging procedures produce the best overall sensitivity, but the specificity for PT/LR (55%) and LNM (57%) was low. With respect to lymph node staging, the best results were obtained with 18F-DOPA PET. 18F-DOPA PET is a new functional imaging procedure for medullary thyroid carcinoma that seems to provide better results than SRS and 18F-FDG PET. Moreover, the data indicate that no single procedure provides adequate diagnostic certainty. Therefore, 18F-DOPA PET is a useful supplement to morphological diagnostic imaging, improving lymph node staging and enabling a more specific diagnosis of primary tumour and local recurrence.

Whole-body MRI in the detection of bone marrow infiltration in patients with plasma cell neoplasms in comparison to the radiological skeletal survey

To compare the diagnostic value of whole-body MRI versus radiological skeletal survey (RSS) in staging patients with plasma cell neoplasms (PCN) and to evaluate the possible therapeutic impact of the replacement of RSS by whole-body MRI. Fifty-four patients with PCN [multiple myeloma (MM), n=47; monoclonal gammopathy of unknown significance (MGUS), n=7] were studied by whole-body MRI and RSS in a monocenter prospective analysis from August 2002 to May 2004. The MRIs were performed using a rolling table platform “AngioSURF” for unlimited field of view with a 1.5-T system (Magnetom Sonata/Maestro Class, Siemens Medical Solutions, Erlangen, Germany). A coronal STIR sequence (TR5500-4230/TE102-94/TI160) was used for imaging of the different body regions, including the head, neck, thorax, abdomen, pelvis and upper and lower extremities. The RSS consisted of eight different projections of the axial and appendicular skeleton. In 41/54 (74%) patients, the results of the whole-body MRI and RSS were concordant. In 11/54 (20%) patients, both imaging techniques were negative. Bone involvement was observed in 30/54 (55%) patients; however, whole-body MRI revealed this more extensively than the RSS in 27/30 (90%) patients with concordant positive imaging findings. In 3/30 (10%) patients, both imaging techniques demonstrated a similar extent of bone marrow infiltration. In 10/54 (19%) patients, the whole-body MRI was superior to RSS in detecting bone marrow infiltration, whereas the RSS was negative. In 3/54 (6%) patients, the RSS was proven to be false positive by the clinical course, whereas the whole-body MRI was truly negative. Whole-body MRI is a fast and highly effective method for staging PCN patients by the use of a rolling table platform. Moreover, it is more sensitive and specific than RSS and reveals bone marrow infiltration and extensive disease more reliably. Therefore, whole-body MRI should be performed as an additional method of exactly staging PCN patients and - with more data in the field - may even prove to be an alternate and more sensitive staging procedure than RSS in PCN patients.

Long-term Outcomes After First-Generation Autologous Chondrocyte Implantation for Cartilage Defects of the Knee

Background: Autologous chondrocyte implantation (ACI) represents an established surgical therapy for large cartilage defects of the knee joint. Although various studies report satisfying midterm results, little is known about long-term outcomes. Purpose: To evaluate long-term clinical and magnetic resonance imaging (MRI) outcomes after ACI. Study Design: Case series; Level of evidence, 4. Methods: Between January 1997 and June 2001, a total of 86 patients were treated with ACI for isolated cartilage defects of the knee. The mean patient age at the time of surgery was 33.3 ± 10.2 years, and the mean defect size was 6.5 ± 4.0 cm2. Thirty-four defects were located on the medial femoral condyle and 13 on the lateral femoral condyle, while 6 patients were treated for cartilage defects of the trochlear groove and 17 for patellar lesions. At a mean follow-up of 10.9 ± 1.1 years, 70 patients (follow-up rate, 82%) treated for 82 full-thickness cartilage defects of the knee were available for an evaluation of knee function using standard instruments, while 59 of these patients were additionally evaluated by 1.5-T MRI to quantify the magnetic resonance observation of cartilage repair tissue (MOCART) score. Clinical function at follow-up was assessed by means of the Lysholm score, the International Knee Documentation Committee (IKDC) score, and the Knee injury and Osteoarthritis Outcome Score (KOOS). Patient activity was assessed by the Tegner score. In addition, pain on a visual analog scale (VAS) and patient satisfaction were evaluated separately. Results: At follow-up, 77% reported being “satisfied” or “very satisfied.” The mean IKDC score at follow-up was 74.0 ± 17.3. The mean Lysholm score improved from 42.0 ± 22.5 before surgery to 71.0 ± 17.4 at follow-up (P < .01). The mean pain score on the VAS decreased from 7.2 ± 1.9 preoperatively to 2.1 ± 2.1 postoperatively. The mean MOCART score was 44.9 ± 23.6. Defect-associated bone marrow edema was found in 78% of the cases. Nevertheless, no correlation between the MOCART score and clinical outcome (IKDC score) could be found (Pearson coefficient, r = 0.173). Conclusion: First-generation ACI leads to satisfying clinical results in terms of patient satisfaction, reduction of pain, and improvement in knee function. Nevertheless, full restoration of knee function cannot be achieved. Although MRI reveals lesions in the majority of the cases and the overall MOCART score seems moderate, this could not be correlated with long-term clinical outcomes.

Detection and characterization of benign focal liver lesions with multislice CT.

MDCT is a rapidly evolving technique that significantly improves CT imaging for several indications including depiction of focal benign lesions. Imaging mainly profits from improved longitudinal spatial resolution allowing high-quality non-axial reformations and 3D reconstructions and CT angiography as well as rapid accurate multiphase imaging with short breath-holding periods. This review provides an overview of the current status of MDCT with respect to liver imaging and the implications for characterizing benign focal liver lesions. MDCT currently allows the acquisition of thin slices in daily routine diagnostics providing an improved detection rate of small liver lesions. Whereas large benign focal liver lesions exhibit typical patterns of morphology, attenuation and perfusion, which also may be assessed with single-slice scanners, small lesions remain challenging even with MDCT, since the specific criteria for confident diagnosis become more ambiguous. Here, MR imaging provides more detailed information about tissue components and the availability of liver-specific contrast agents, adding further impact to this technique. With respect to dose considerations, the number of necessary multiphase scans as well as the application of very thin collimation should be strictly checked for each patient undergoing MDCT based on the individual clinical situation and question.

Sinonasal computed tomography in patients with Wegener's granulomatosis.

The goal of this study was to describe pathologies of sinonasal CT in patients with Wegeners granulomatosis. Between 1993 and 2004, sinonasal CT was performed in 28 patients (15 male, 13 female) with Wegeners granulomatosis. The following imaging findings were assessed on the CT scans: mucosal thickening, subtotal opacification, air-fluid level, bony destruction, sclerosing osteitis, bony thickening, orbital mass, and saddle nose deformity. Of the 28 patients, 61% showed mucosal thickening in the nasal cavity and 75% in the paranasal sinuses. A subtotal opacification of the paranasal sinuses was detected in 25%, and of the mastoid cells in 7% of patients. Fifty-seven percent of patients had bony destruction of the nasal cavity, and 54% of the paranasal sinuses. CT revealed sclerosing osteitis of the paranasal sinuses in 21%, and of the mastoid cells in 18% of patients. Bony thickening of the paranasal sinuses was detected in 18%, and of the mastoid cells in 14% of patients. With respect to all imaging findings, the maxillary sinuses were the most frequently affected paranasal sinuses. The authors conclude that the following sinonasal CT findings are observed in patients with Wegeners granulomatosis: (1) bony destruction, mainly of the nasal cavity, maxillary sinuses, and mastoid cells; (2) sclerosing osteitis, mainly of the maxillary sinuses and mastoid cells; (3) bony thickening, mainly of the maxillary sinuses and mastoid cells; and (4) mucosal thickening, mainly of the maxillary sinuses. These findings are, however, nonspecific and should be combined with other clinicopathologic and laboratory studies to confirm the diagnosis of Wegeners granulomatosis.

Diagnosis of the hypothenar hammer syndrome by high-resolution contrast-enhanced MR angiography

Abstract. Our objective was to describe the imaging features of hypothenar hammer syndrome using minimally invasive contrast-enhanced MR angiography in comparison with oscillography study. In five patients with hypothenar hammer syndrome Gd-BOPTA-enhanced elliptically reordered 3D pulse sequence MR was compared with oscillography findings and clinical symptoms focusing on angiographic appearance of vessel injury, distribution pattern of hand vasculature and joining branches between the radial and ulnar artery supply. All patients showed segmental occlusion at the site of trauma impact with varying involvement of the superficial palmar arch, common volar digital arteries. Embolic disease was present in 50% of patients and could be clearly identified with MRA. Good correspondence was found between angiographic appearance including the presence of collaterals, clinical symptoms and oscillography. Bilateral comparison was helpful in distinguishing between vessel variants and pathology. Bilateral Gd-BOPTA-enhanced MR angiography is a minimally invasive method to depict clearly the localization and extent of vessel injury in hypothenar hammer syndrome providing valuable information about distribution pattern of hand vasculature and presence of collaterals; however, no flow data can be obtained.

Computed tomography coronary angiography with 370-millisecond gantry rotation time : Evaluation of the best image reconstruction interval

Objective: To evaluate the best reconstruction window for noninvasive coronary angiography when using a 16-detector row computed tomography (CT) scanner with a gantry rotation time of 370 milliseconds. Methods: In a pilot study, 189 coronary artery segments of 21 patients with a mean heart rate of 65 beats per minute (bpm, maximum: 45-94 bpm) were investigated using a 16-detector row CT scanner. Raw data were reconstructed in 10% increments from 40% to 70% of the RR interval. Two experienced observers independently evaluated the image quality of the coronary arteries in a segmental fashion. A 5-point ranking scale was applied, with 1 being very poor (no evaluation possible); 2, poor; 3, moderate; 4, good; and 5, very good. Results: In the mean of all patients, the best reconstruction window was found to be at 60% of the RR interval. In patients with higher heart rates, the best reconstruction window was found to be at an earlier stage of the R wave-to-R wave interval. Conclusions: Initial results show that good diagnostic image quality could be achieved for all evaluated segments of the coronary tree with image reconstructions at 60% of the R wave-to-R wave interval in patients with heart rates of 70 bpm or less. Using a 16-detector row CT scanner with a gantry rotation time of 370 milliseconds, the need for adapting the reconstruction window to each segment for the best image quality was overcome in those cases. In patients with heart rates faster than 70 bpm, reconstructions at an earlier stage within the cardiac cycle were necessary.

Ectopic Thyroid Gland in the Porta Hepatis and Lingua

A rare case of an ectopic thyroid gland in the porta hepatis and in the tongue in an asymptomatic euthyroid 24-year-old woman is reported. A solitary inhomogeneous, hypoechogenic and hyperechogenic mass in the porta hepatis was accidentally discovered by ultrasonography. Subsequent computed tomography demonstrated a heterogeneous, well-defined tumor with small calcifications without signs of environmental invasion. A hemangioma and focal nodular hyperplasia were excluded by blood pool and hepatobiliary scintigraphy. Surprisingly, fine-needle aspiration cytology revealed normal thyroid tissue. (123)I-scintigraphy confirmed the presence of ectopic dual thyroid tissue in the hepatic porta and lingua. At clinical inspection the lingual thyroid gland was palpable and visible, and appeared solid and spheroidal. The subhepatic, ectopic thyroid mass was resected. Postoperatively, thyroid hormone replacement was started to prevent an enlargement of the lingual thyroid. Today, 4 years after surgery, the patient remains euthyroid.

Radiological findings in Boerhaave's syndrome

The aim was to define the diagnostic value of chest radiography, esophagography, and computed tomography (CT) in patients with Boerhaaves syndrome. CT findings in 14 patients (11 male, 3 female; mean age: 60 years; median age: 66 years; age range: 36–78 years) with spontaneous esophageal perforation were retrospectively reviewed and compared to those of esophagography (n=11) and chest radiography (n=14). In six patients unenhanced CT scans were available; in ten patients (2/10 patients had an unenhanced CT before) a contrast-enhanced CT was performed as an emergency investigation. In 5/14 patients additional oral contrast medium was given. Chest radiography revealed pleural effusions in 9/14 and infiltrates in 9/14 patients. Pneumothorax and pneumopericardium were observed in two patients each. Pneumomediastinum was seen in three patients. Two chest radiographs were normal. Esophagography performed in 11 patients demonstrated contrast medium extravasation at a supradiaphragmatic level in seven patients, indicating esophageal perforation with esophagopleural fistula, and a submucosal contrast medium collection in four cases. Unenhanced CT scans revealed four intramural hematomas with typical localization. Unenhanced and contrast-enhanced CT demonstrated periesophageal air collections indicating esophageal perforation in all patients. Pleural effusions were seen in 11/14 and infiltrates in 8/14 patients. Contrast medium extravasation was observed in 5/14 patients, whereas a thickening of the esophageal wall was depicted in 11/14 patients. Periaortic air tracks (n=7), pneumothorax (n=3), pneumomediastinum (n=6), and mediastinal fluid collections (n=7) were depicted in CT. By demonstrating periesophageal air tracks suggestive of esophageal perforation, CT reveals the decisive criteria for diagnosing Boerhaaves syndrome and should therefore be performed in the diagnostic work-up of patients in whom this syndrome is part of the differential diagnosis.

Comparative diagnostic value and therapeutic relevance of magnetic resonance imaging and bone marrow scintigraphy in patients with metastatic solid tumors of the axial skeleton

PURPOSE To evaluate the comparative impact of magnetic resonance imaging (MRI) and bone marrow scintigraphy (BMS) in bone marrow metastases of solid tumors. METHODS In 20 patients with solid tumors MRI of the axial skeleton and whole-body BMS were retrospectively reviewed. Detectability of metastases, extent of disease and therapeutic implications were assessed. RESULTS In 15/20 (75%) patients MRI and BMS concordantly revealed bone marrow metastases of the axial skeleton. In nine of these 15 patients (60%) MRI showed more metastases. Local radiotherapy or surgery was performed in seven of these cases (78%). BMS detected additional metastases of the appendicular skeleton in 8/15 (53%) patients. In 4/20 cases (20%) the imaging findings were discordant. In three patients with degenerative changes (n=2) or lipoma (n=1) BMS was false positive. In another patient BMS failed to detect metastases proven by MRI and clinical follow-up resulting in subsequent radiation therapy. One patient had normal bone marrow. CONCLUSION MRI appears to be more sensitive and specific in the detection of bone marrow metastases in the axial skeleton and is of clinical importance for subsequent local therapy.