Is true FISP imaging reliable in the evaluation of venous thrombosis?

OBJECTIVE: The objective of our study was to evaluate the accuracy of true fast imaging with steady-state precession (FISP) in the diagnosis of venous thrombosis using gadolinium-enhanced 3D T1-weighted gradient-echo images and correlative imaging as the gold standard. MATERIALS AND METHODS: Twenty-five MR examinations were retrospectively reviewed independently by two radiologists to rule out thrombosis in the central veins of the body. The presence of venous thrombus was assessed separately in 80 veins using true FISP and gadolinium-enhanced T1-weighted images. Diagnosis was confirmed by another imaging technique (sonography, CT, and/or conventional venography) in all positive cases. Negative examinations were confirmed using imaging, clinical follow-up, or both. RESULTS: Venous thrombosis was present in 25 veins in 18 patients. True FISP images had a lower sensitivity (66%) and specificity (70.9%) for the diagnosis of venous thrombosis than gadolinium-enhanced MR images (p < 0.01). CONCLUSION: True FISP images have lower sensitivity and specificity in the diagnosis of venous thrombosis than gadolinium-enhanced T1-weighted gradient-echo images. True FISP images should not be used exclusively for the diagnosis of venous thrombosis.     

Science to Practice: Can MR imaging replace liver biopsy for the diagnosis of early fibrosis?

A method that could be used to accurately assess portal venous pressure would be valuable when diagnosing portal hypertension, evaluating patient prognosis, and monitoring the progress of therapy. Baik et al have suggested that a qualitative noninvasive Doppler US parameter can be used to monitor therapy of portal hypertension. Further clinical investigation is needed to confirm these results and to determine whether hepatic venous Doppler waveform tracings can be used to monitor patient response to therapy. Ongoing research suggests that microbubble contrast agents may enable a more quantitative noninvasive estimate of intravascular pressures with US.     

Can contrast-enhanced ultrasonography replace multidetector-computed tomography in the detection of liver metastases from colorectal cancer?

Purpose

To compare the sensitivity and specificity of contrast-enhanced ultrasonography (CEUS) and 4-slice multidetector-computed tomography (MDCT) in the detection of liver metastases in patients with colorectal cancer (CRC).

Materials and methods

Candidates for this prospective study were 461 consecutive patients referred to the Department of Colorectal Surgery, Aarhus University Hospital with primary or local recurrence of CRC. The patients underwent liver ultrasonography (US), CEUS, MDCT and intraoperative ultrasonography (IOUS). Fine-needle biopsy was performed on all suspicious lesions. The examinations were interpreted blindly and the combination of US, CEUS, biphasic MDCT, IOUS, follow up and biopsy was the gold standard.

Results

Three hundred and sixty-five patients were included. All patients had undergone preoperative US, CEUS and MDCT and 65.5% had received IOUS. The gold standard found liver metastases in 54 patients (14.8%). Multidetector CT found significantly more metastases than CEUS in 15 (28%) of the patients (p = 0.02). In a patient-by-patient analysis MDCT had a non-significantly higher sensitivity in the detection of liver metastases compared to CEUS (0.89 versus 0.80, p = 0.06). The specificity of CEUS (0.98) was slightly better than that of MDCT (0.94) (p = 0.02).

Conclusion

Multidetector CT found significant more metastases than CEUS, and MDCT had in patient-by-patient analysis a non-significant better sensitivity (p = 0.06) in detecting liver metastases in patients with CRC.     

Diagnosis of chondral lesions of the knee joint: can MRI replace arthroscopy?

The role of magnetic resonance tomography (MRI) for the diagnosis of chondral lesions of the knee joint is still unclear. The sensitivity of the method ranges from 15% to 96%. The scope of our daily experiences showed that there were considerable deviations between the tomographical and arthoscopical results, which vary from the results of experimental studies. Therefore we have conducted a prospective study to investigate the question of how MRI can replace arthroscopy (ASC) in the diagnosis of cartilage damages in the scope of daily routine. All 195 patients included in this study received a magnetic resonance tomography followed by an arthroscopy. A clear diagnosis of supposition had to be determined before the magnetic resonance tomography. The patients were divided into 3 Groups. Group A ( n =86) received a standard Military Hospital Ulm (MH) MRI — sagittal STIR TSE and PD TSE, coronal and transversal T2 FFE (TR=660 ms, TE=18 ms, FA=30°, 512 matrix). In addition, one sub-Group, AK (n =21) was examined with a special cartilage sequence of the cartilage fs T1 W FFE. Neither patients in Group AK nor in Group A as a whole received any contrast medium. Group B (n =88) was examined with an alternate MRI protocol (Radiological Joint Practice, Neu-Ulm — sagittal T1 SE, T2 SE and T2 FLASH (TR=608 ms, TE=18 ms, FA=20°, 256 matrix), coronal PD fs), employing gadolinium as a contrast medium. 156 cartilage lesions were found arthroscopically. In Group A the sensitivity was 33%, the specificity 99%, and the positive and negative prediction values 75% and 98% respectively. Group B reached a sensitivity of 53% and a specificity of 98%. The positive prediction value was 48% and the negative was 98%. Group AK showed a sensitivity of 38% and specificity of 98%; the positive and negative prediction values came to 50% and 97% respectively. In conclusion, our results indicate that the MRI examination techniques recommended in the literature at present are not able to replace the ASC for the diagnosis of cartilage damages of the knee joint. In view of the high specificity (97%–99%) and the high negative prediction value (97%–98%), MRI is suitable for the exclusion of cartilage lesions. For a negative MRI associated with a cartilage injury, a cautious attitude towards an operative cartilage treatment is therefore justified. Because the MRI can not replace the ASC for diagnostic of cartilage damage, the ASC still has to be seen as the method of choice for the evaluation of cartilage damage.     

Can hysterosalpingocontrast-sonography replace hysterosalpingography in the assessment of tubal subfertility?

INTRODUCTION: Hysterosalpingo-contrastsonography (HyCoSy) is a new method for assessing tubal patency using transvaginal ultrasound. It is thought to have several advantages over conventional hysterosalpingography (HSG). We prospectively evaluated the performance of HyCoSy and HSG in the diagnosis of tubal pathology. METHODS AND PATIENTS: One-hundred consecutive subfertile women underwent both HyCoSy and HSG in randomised order. Results of both tests were related to findings at laparoscopy with dye, which was used as the reference test. Each woman was asked to score the pain exsperienced at both procedures on a visual analogue scale. RESULTS: When laparoscopy with dye was used as reference test, the likelihood ratios of HyCoSy were slightly inferior to those obtained for HSG. Since the performance of HyCoSy was dependent on experience, the results were recalculated omitting the 50 initial procedures from the analysis. In that calculation, results of HyCoSy and HSG were comparable. There were no differences in pain experienced during the procedure, as there appeared also to be no differences in patient preferences. CONCLUSION: There appear to be no strong arguments either to replace HSG by HyCoSy, or to reject the use of HyCoSy. Both procedures can be used in the evaluation of tubal pathology.     

Tendo-ligamentous pathologies of the wrist joint: Can ultrasonography replace magnetic resonance imaging?

Background

Characterization of tendo-ligamentous pathologies of wrist remains problematic, despite advances in imaging. By using clinical history and imaging appearance, one can determine the diagnosis. USG is used as first imaging modality whereas MRI aids in making a specific diagnosis of few of the lesions.

Can diffusion-weighted MRI replace conventional contrast enhanced MRI in the differentiation between benign and malignant pancreatic masses?

Purpose

To evaluate the role of diffusion weighted MRI (DW MRI) in the differentiating between benign and malignant pancreatic masses.

Ultrasound: Can it replace CT in the evaluation of pneumonia in pediatric age group?

Aim of the study

To evaluate the ultrasound efficiency in the assessment of pneumonia in pediatric age group compared to CT as a trial for radiation exposure reduction.

Spontaneous detorsion of the ovary: Can it be diagnosed by MRI?

PURPOSE: To determine whether recent progress in imaging has made it possible to diagnose spontaneous detorsion, which is an accepted concept in the gynecological literature but until now has been a presumptive diagnosis that could not be confirmed because of the lack of imaging proof. MATERIALS AND METHODS: We searched for patients who had a diagnosis of spontaneous detorsion on MRI between January 2000 and January 2003, and selected only patients who met a selection of strict criteria, including mainly enlargement and hyperintensity of ovarian stroma on T2-weighted (T2W) images, clinical findings compatible with torsion and detorsion, and return of the stroma to normal size on follow-up examinations. Other signs of torsion, such as tubal thickening, were appreciated but not mandatory. Clinical follow-up for at least three years was available. RESULTS: Four patients met the study criteria. No stabilizing procedure was performed in the ovaries. One patient recurred and lost her ovary. CONCLUSION: The diagnosis of torsion followed by spontaneous detorsion was made with high probability in a selected number of patients. The clinical management of such patients remains a matter of debate. Laparoscopy with oophoropexy would be useful for young patients in whom close follow-up cannot be achieved.     

Preoperative detection of colorectal liver metastases in fatty liver: MDCT or MRI?

Objective

To compare the diagnostic value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative detection of colorectal liver metastases in diffuse fatty infiltration of the liver, associated with neoadjuvant chemotherapy.

Materials and methods

Twenty preoperative tri-phasic MDCT (4-64-row, Siemens) and dynamic contrast-enhanced MRI (1.5 T or 3.0 T, Siemens) examinations of patients with colorectal cancer and liver metastases in diffuse steatosis were retrospectively evaluated. All patients underwent surgical resection for liver metastases (time interval 1-60 days). The amount of fatty infiltration of the liver was determined histopathologically by semi-quantitative percent-wise estimation and ranged from 25 to 75%.

Results

Overall, 51 metastases were found by histopathology of the resected liver segments/lobes. The size of the metastases ranged from 0.4 to 13 cm, with 18 (35%) being up to 1 cm in diameter. In the overall rating, MDCT detected 33/51 lesions (65%), and MRI 45/51 (88%). For lesions up to 1 cm, MDCT detected only 2/18 (11%) and MRI 12/18 (66%). One false positive lesion was detected by MDCT. Statistical analysis showed that MRI is markedly superior to MDCT, with a statistically significant difference (p < .001), particularly for the detection of small lesions (≤1 cm; p < .004). There was no significant difference between the two modalities in the detection of lesions > 1 cm.

Conclusion

For the detection of colorectal liver metastases after neoadjuvant chemotherapy and consecutive diffuse fatty infiltration of the liver, MRI is superior to MDCT, especially for the detection of small lesions.     

Can virtual non-enhanced CT be used to replace true non-enhanced CT for the detection of palpable cervical lymph nodes? A preliminary study

Purpose

To investigate the potential of virtual non-contrast CT (VNCT) from dual-energy CT to replace true nonenhanced CT (TNCT) for the detection of enlarged cervical lymph nodes.

Materials and methods

Thirty-nine patients with 94 histopathologically proven cervical lymph nodes were imaged with the dual-energy CT technique. VNCT images from the arterial [VNCT-A] and venous phases [VNCT-V] were obtained with the liver VNC application. The mean CT number and signal-to-noise ratio (SNR) were compared. Image quality was evaluated with a score scale of 1–5. Effective dose (ED) was calculated and compared.

Results

Mean CT numbers of cervical lymph nodes were higher on VNCT than on TNCT (P = 0.034). There was no difference in the SNR among three sets of non-enhanced CT images, but the CNR of VNCT images was higher than that of TNCT images (P < 0.001). Image quality of VNCT from two phases was comparable to that of TNCT (P = 0.070). There was no difference in image quality of three sets of non-enhanced CT images (P > 0.05). ED from dual-phase dual-energy CT was lower than that from tri-phase CT scans (P < 0.001).

Conclusion

VNCT images from dual-energy CT of the neck had diagnostic image quality; they have the potential to replace TNCT, thus reducing the radiation dose.     

Can Doppler sonography grade the severity of hepatitis C-related liver disease?

OBJECTIVE: Many authors have claimed that Doppler sonography indexes are of value in grading and assessing diffuse liver disease. However, there is much controversy regarding the reliability and reproducibility of these techniques. We performed a prospective study to evaluate whether these methods can grade disease in a well-stratified cohort of patients with hepatitis C virus (HCV)-related liver disease. SUBJECTS AND METHODS: Sixty-five patients with biopsy-proven HCV-related liver disease were recruited, and Doppler sonography was performed by one operator. The patients were classified into one of the following three groups on the basis of the Ishak-modified histologic activity index (HAI) fibrosis (F) and necroinflammatory (NI) scores: mild hepatitis (F < or = 2 and NI < or = 3), moderate or severe hepatitis (3 < or = F < 6 or NI > or = 4), or cirrhosis (F = 6/6). We measured the following Doppler indexes: main hepatic artery peak velocity (Vmax) and resistive index, main portal vein peak velocity (Vmax), and maximal portal vein diameter and circumference that allowed calculation of the portal vein congestive index (portal vein area and portal vein velocity). The ratio of the hepatic artery velocity (Vmax) to the portal vein velocity (Vmax) was also calculated, and the phasicity (triphasic, biphasic, or monophasic) of the hepatic veins of each patient was recorded. We also measured the maximal spleen length longitudinally. RESULTS: A total of 65 patients with liver disease (mild hepatitis, n = 20; moderate or severe hepatitis, n = 25; cirrhosis, n = 20) with biopsy-proven HCV-related liver disease were studied. Optimal hepatic arterial traces were obtained in only 30 patients and portal vein circumference in 18 patients. No significant differences were observed in the Doppler indexes with increasing severity of liver disease. Five (29%) of 17 patients with mild hepatitis had an abnormal hepatic vein trace (i.e., biphasic or monophasic) compared with 11 (55%) of 20 patients with moderate or severe hepatitis and 12 (60%) of 20 patients with cirrhosis. The only index to show a significant intergroup difference was splenic length (analysis of variance, p < 0.001), but there was still overlap between the groups. CONCLUSION: Doppler-derived indexes, which have previously been recommended for the assessment of severity in chronic liver disease, are difficult to reproduce reliably and therefore have a limited clinical role in the noninvasive assessment of hepatic fibrosis or inflammation.     

Can MRI Visual Assessment Differentiate the Variants of Primary-Progressive Aphasia?

BACKGROUND AND PURPOSE:Primary-progressive aphasia is a clinically and pathologically heterogeneous condition. Nonfluent, semantic, and logopenic are the currently recognized clinical variants. The recommendations for the classification of primary-progressive aphasia have advocated variant-specific patterns of atrophy. The aims of the present study were to evaluate the sensitivity and specificity of the proposed imaging criteria and to assess the intra- and interrater reporting agreements.MATERIALS AND METHODS:The cohort comprised 51 patients with a root diagnosis of primary-progressive aphasia, 25 patients with typical Alzheimer disease, and 26 matched control participants. Group-level analysis (voxel-based morphometry) confirmed the proposed atrophy patterns for the 3 syndromes. The individual T1-weighted anatomic images were reported by 3 senior neuroradiologists.RESULTS:We observed a dichotomized pattern of high sensitivity (92%) and specificity (93%) for the proposed atrophy pattern of semantic-variant primary-progressive aphasia and low sensitivity (21% for nonfluent-variant primary-progressive aphasia and 43% for logopenic-variant primary-progressive aphasia) but high specificity (91% for nonfluent-variant primary-progressive aphasia and 95% for logopenic-variant primary-progressive aphasia) in other primary-progressive aphasia variants and Alzheimer disease (sensitivity 43%, specificity 92%). MR imaging was least sensitive for the diagnosis of nonfluent-variant primary-progressive aphasia. Intrarater agreement analysis showed mean κ values above the widely accepted threshold of 0.6 (mean, 0.63 ± 0.16). Pair-wise interobserver agreement outcomes, however, were well below this threshold in 5 of the 6 possible interrater contrasts (mean, 0.41 ± 0.09).CONCLUSIONS:While the group-level results were in precise agreement with the recommendations, semantic-variant primary-progressive aphasia was the only subtype for which the proposed recommendations were both sensitive and specific at an individual level.

Primary-progressive aphasia (PPA) is a clinically and pathologically heterogeneous condition characterized by insidious onset and gradual worsening of language due to degeneration of brain language areas. Clinical heterogeneity, compounded by the evolution of signs and symptoms, makes accurate classification of patients a challenging task. Making a reliable clinical diagnosis, on the other hand, is important. Despite lack of a one-to-one relationship between the clinical diagnosis and the underlying pathology, previous clinicopathologic series have identified probabilistic associations among the 3 recognized clinical presentations of PPA and certain pathologies. There are established associations between semantic-variant PPA (svPPA) and frontotemporal lobar degeneration–TAR DNA binding protein 43 (TDP-43); nonfluent-variant PPA (nfvPPA) and frontotemporal lobar degeneration-tau; and logopenic-variant PPA (lvPPA) and Alzheimer pathology.^1–5The recommendations on clinical subtyping of PPA have proposed that clinical classification can be supported by imaging according to the pattern of regional atrophy or metabolic impairment.⁶ Left posterior frontoinsular atrophy in nfvPPA, anterior temporal atrophy in svPPA, and left posterior peri-Sylvian or parietal atrophy in lvPPA are the recommended atrophy patterns. Remarkably, these imaging recommendations are derived from studies that either used group-averaged data—which though highly replicated,^7–10 are not necessarily valid for single-patient diagnosis—or were based on observed atrophy in convenience samples^9–14 without qualification of sensitivity, specificity, or reliability. Little is known about whether individual patients, as opposed to groups, fulfilling the clinical criteria for these variants reliably present with the prescribed patterns of atrophy and whether these patterns have sufficient reliability to be exploited to arrive at an accurate syndromic diagnosis.The aims of the present study were the following: 1) to evaluate the utility of the proposed imaging criteria for the diagnosis of PPA variants by contrasting the patterns of atrophy in individual patients with PPA, as reported by senior neuroradiologists, with the recommendations from the criteria; and 2) to assess the neuroradiologists'' intra- and interrater agreement, which, in turn, would be an indication of the robustness of the observed abnormalities.