Accuracy of chemical shift MR imaging in diagnosing indeterminate bone marrow lesions in the pelvis: review of a single institution’s experience

Objective

To re-assess the accuracy of chemical shift imaging in diagnosing indeterminate bone marrow lesions as benign or malignant.

Materials and methods

We retrospectively reviewed our experience with MR imaging of the pelvis to assess the accuracy of chemical shift imaging in distinguishing benign from malignant bone lesions. Two musculoskeletal radiologists retrospectively reviewed all osseous lesions biopsied since 2006, when chemical shift imaging was added to our routine pelvic imaging protocol. Study inclusion criteria required (1) MR imaging of an indeterminate bone marrow lesion about the pelvis and (2) subsequent histologic confirmation. The study group included 50 patients (29 male, 21 female) with an average age of 67 years (range, 41–89 years). MR imaging results were evaluated using biopsy results as the “gold standard.”

Results

There were 27 malignant and 23 benign lesions. Chemical shift imaging using an opposed-phase signal loss criteria of less than 20 % to indicate a malignant lesion, correctly diagnosed 27/27 malignant lesions and 14/23 benign lesions, yielding a 100 % sensitivity, 61 % specificity, 75 % PPV, 100 % NPV, and 82 % accuracy. The area under the receiver operator characteristic (ROC) curve was 0.88. The inter-rater and intra-rater agreement K values were both 1.0.

Conclusions

Chemical shift imaging is a useful adjunct MR technique to characterize focal and diffuse marrow abnormalities on routine non-contrast pelvic imaging. It is highly sensitive in identifying malignant disease. Despite its lower specificity, the need for biopsy could be eliminated in more than 60 % of patients with benign disease.     

3-T breast magnetic resonance imaging in patients with suspicious microcalcifications on mammography

Objective

To investigate the diagnostic value of 3-Tesla (T) breast MRI in patients presenting with microcalcifications on mammography.

Methods

Between January 2006 and May 2009, 123 patients with mammographically detected BI-RADS 3–5 microcalcifications underwent 3-T breast MRI before undergoing breast biopsy. All MRIs of the histopathologically confirmed index lesions were reviewed by two breast radiologists. The detection rate of invasive carcinoma and ductal carcinoma in situ (DCIS) was evaluated, as well as the added diagnostic value of MRI over mammography and breast ultrasound.

Results

At pathology, 40/123 (33 %) lesions proved malignant; 28 (70 %) DCIS and 12 (30 %) invasive carcinoma. Both observers detected all invasive malignancies at MRI, as well as 79 % (observer 1) and 86 % (observer 2) of in situ lesions. MRI in addition to conventional imaging led to a significant increase in area under the receiver operating characteristic (ROC) curve from 0.67 (95 % CI 0.56–0.79) to 0.79 (95 % CI 0.70–0.88, observer 1) and to 0.80 (95 % CI 0.71–0.89, observer 2), respectively.

Conclusions

3-T breast MRI was shown to add significant value to conventional imaging in patients presenting with suspicious microcalcifications on mammography.

Key points

? 3-T MRI is increasingly used for breast imaging in clinical practice. ? On 3-T breast MRI up to 86 % of DCIS lesions are detected. ? 3-T MRI increases the diagnostic value in patients with mammographically detected microcalcifications.     

Characterisation of indeterminate focal breast lesions on grey-scale ultrasound: role of ultrasound elastography

Purpose

This study was undertaken to evaluate the role of ultrasound (US) elastography in characterising focal breast lesions classified as indeterminate on B-mode US.

Materials and methods

Eighty-four focal breast lesions, 64 benign and 20 malignant (mean diameter, 15.1 mm), detected but not characterised on B-mode US in 72 women, Breast Imaging Reporting and Data System (BI-RADS) US category 3 (n=56) or category 4 (n=28), were studied with US elastography and classified in consensus by two radiologists according to a five-point colour scale. Sensitivity, specificity and positive and negative predictive values (PPV and NPV) of US elastography compared with conventional US were calculated in relation to microhistology (n=67) and cytology (n=17), which were used as the reference standard.

Results

A total of 65/84 (77.4%) lesions were correctly classified as benign or malignant using US elastography, whereas the remaining 19/84 (22.6%) were incorrectly assessed. There were no statistically significant differences between US elastography and B-mode US with regard to sensitivity (70% vs. 68.4%), specificity (79.6% vs. 78.5%), PPV (51.8% vs. 48.1%) and NPV 89% vs. 89.5% (p>0.5). By contrast, a statistically significant difference was noted in the evaluation of BI-RADS 3 lesions, in which US elastography had 50% sensitivity, 86% specificity, 30% PPV and 93.5% NPV compared with BI-RADS 4 lesions (78.6%, 57.1%, 64.7% and 72.7%) (p<0.5).

Conclusions

The high NPV of US elastography may help reduce the use of biopsy in BI-RADS 3 lesions, but its low PPV in BI-RADS 4 lesions does not allow avoidance of biopsy on the basis of the US elastographic score alone in this group of lesions.     

Deep pelvic endometriosis: accuracy of pelvic MRI completed by MR colonography

Purpose

This study assessed the diagnostic accuracy of pelvic magnetic resonance (MR) imaging completed by MR colonography for the preoperative evaluation of deep pelvic endometriosis in patients undergoing laparoscopic surgery.

Materials and methods

A total of 143 patients (mean age 34.3±5.1 years) with a clinical suspicion of deep pelvic endometriosis were assessed by pelvic MR and MR colonography. All patients underwent laparoscopic surgery 3–10 weeks after the MR examination. The presence, location, number and extent of endometriotic lesions were evaluated. Data obtained with MR were compared with surgical findings. MR sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and diagnostic accuracy values were calculated for each site by considering the laparoscopic and histological findings as the reference standard.

Results

Laparoscopy confirmed the presence of endometriosis in 119/143 patients (83%); in 76/119 (64%) deep pelvic endometriosis was diagnosed, whereas in the remaining 43/119 (36%), superficial peritoneal implants and endometriomas were found. In 32/119 (27%) patients, intestinal lesions were detected. MR had sensitivity, specificity, PPV, NPV and diagnostic accuracy values of 67–100%, 85–100%, 83–100%, 84–100% and 84–100%, respectively, in recognising lesions located in different pelvic sites.

Conslucions

MR imaging combined with colonography is a highly accurate tool for characterising deep endometriotic lesions in patients scheduled for laparoscopic surgery. In particular, MR colonography has very high accuracy in detecting colorectal involvement.     

Grading of Cerebral Glioma with Multiparametric MR Imaging and 18F-FDG-PET: Concordance and Accuracy

Objectives

To retrospectively evaluate concordance rates and predictive values in concordant cases among multiparametric MR techniques and FDG-PET to grade cerebral gliomas.

Methods

Multiparametric MR imaging and FDG-PET were performed in 60 consecutive patients with cerebral gliomas (12 low-grade and 48 high-grade gliomas). As the dichotomic variables, conventional MRI, minimum apparent diffusion coefficient in diffusion-weighted imaging, maximum relative cerebral blood volume ratio in perfusion-weighted imaging, choline/creatine ratio and (lipid and lactate)/creatine ratio in MR spectroscopy, and maximum standardised uptake value ratio in FDG-PET in low- and high-grade gliomas were compared. Their concordance rates and positive/negative predictive values (PPV/NPV) in concordant cases were obtained for the various combinations of multiparametric MR techniques and FDG-PET.

Results

There were significant differences between low- and high-grade gliomas in all techniques. Combinations of two, three, four, and five out of the five techniques showed concordance rates of 77.0?±?4.8 %, 65.5?±?4.0 %, 58.3?±?2.6 % and 53.3 %, PPV in high-grade concordant cases of 97.3?±?1.7 %, 99.1?±?1.4 %, 100.0?±?0 % and 100.0 % and NPV in low-grade concordant cases of 70.2?±?7.5 %, 78.0?±?6.0 %, 80.3?±?3.4 % and 80.0 %, respectively.

Conclusion

Multiparametric MR techniques and FDG-PET have a concordant tendency in a two-tiered classification for the grading of cerebral glioma. If at least two examinations concordantly indicated high-grade gliomas, the PPV was about 95 %.

Key Points

? Modern imaging techniques can help predict the aggressiveness of cerebral gliomas. ? Multiparametric MRI and FDG-PET have a concordant tendency to grade cerebral gliomas. ? Their high-grade concordant cases revealed at least 95 % positive predictive values. ? Their low-grade concordant cases revealed about 70–80 % negative predictive values.     

MR-arthrography in superior instability of the shoulder: correlation with arthroscopy

Purpose

This study was undertaken to evaluate magnetic resonance (MR) arthrography in the detection and classification of lesions that may cause superior instability.

Materials and methods

Forty-two consecutive patients with clinical signs of chronic superior instability of the shoulder underwent MR arthrography followed by arthroscopic surgery. For each patient we retrospectively reviewed the MR arthrography and surgical findings.

Results

We detected 31 superior labral anterior posterior (SLAP) lesions, all confirmed on arthroscopy with three cases of underestimation: in the detection of SLAP lesions, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of MR arthrography were 100%; in the evaluation of the type of SLAP lesion, sensitivity was 100%, specificity was 78.5%, accuracy was 92.8%, PPV was 71.7% and NPV was 100%. All cases of capsular laxity (13/42) and biceps tendon lesions (3/42) were confirmed on arthroscopy with sensitivity, specificity, accuracy, PPV and NPV of 100%. Eleven cuff lesions were detected on MR arthrography, 10 of which confirmed at arthroscopy: sensitivity was 100%, specificity was 96.8%, accuracy was 97.6%, PPV was 90.9% and NPV was 100%. Associated lesions were found in 38/42 patients.

Conclusions

Superior instability is frequently associated with different anatomical variants or pathological conditions, such as SLAP lesions. The role of MR arthrography is to describe the key features of lesions affecting the superior portion of the shoulder, including location, morphology, extent, and associated injuries and leanatomical variants and to correlate these features with clinical symptoms.     

Do clinical and radiologic features help predict malignancy of B3 breast lesions without epithelial atypia (B3a)?

Objectives

To evaluate excision histology outcome of B3a lesions diagnosed at imaging-guided core biopsy and assess whether clinical and radiologic features may predict upgrade to malignancy.

Methods

A total of 153 B3a lesions (74 papillomas, 51 radial scars and 28 fibro-epithelial lesions) that underwent surgical excision were assessed. PPV for malignancy in all B3a lesions and specific for each sub-category was evaluated. Multivariate analysis was conducted to identify association between clinical (age, family or personal history of breast cancer, symptoms), diagnostic findings (imaging modality, lesion size, final BI-RADS category) and final excision outcome.

Results

Eleven (7%) of 153 B3a lesions were upgraded to malignancy. All carcinomas diagnosed on excision were non-high grade DCIS. Following features were significantly associated with malignancy: lesions identified only on mammography (3/21; 14%), both mammography and ultrasound (7/44; 16%), lesion size?>?10 mm (10/74; 13.5%) and BI-RADS category 4-5 (8/29; 27.6%). The absence of residual microcalcification after biopsy was associated with decreased risk for malignancy (15/16[93.7%]; p?=?0.0297). Lesion size?>?10 mm (OR?=?9.3832; 95%; p?=?0.0398) and BI-RADS category 4–5 (OR?=?12.6004; 95%; p?=?0.0006) were found to be independent predictors of upgrade to malignancy.

Conclusions

B3a lesions are associated with low risk of malignancy at excision. Lesion size?>?10 mm and BI-RADS 4–5 category may represent useful predictors of upgrade to malignancy.

     

Hepatocellular carcinoma in cirrhotic patients: prospective comparison of US, CT and MR imaging

Objectives

To prospectively compare the diagnostic performance of ultrasound (US), multidetector computed tomography (MDCT) and contrast-enhanced magnetic resonance imaging (MRI) in cirrhotic patients who were candidates for liver transplantation.

Methods

One hundred and forty consecutive patients with 163 hepatocellular carcinoma (HCC) nodules underwent US, MRI and MDCT. Diagnosis of HCC was based on pathological findings or substantial growth at 12-month follow-up. Four different image datasets were evaluated: US, MDCT, MRI unenhanced and dynamic phases, MRI unenhanced dynamic and hepatobiliary phase. Diagnostic accuracy, sensitivity, specificity, PPV and NPV, with corresponding 95 % confidence intervals, were determined. Statistical analysis was performed for all lesions and for three lesion subgroups (<1 cm, 1-2 cm, >2 cm).

Results

Significantly higher diagnostic accuracy, sensitivity and NPV was achieved on dynamic + hepatobiliary phase MRI compared with US, MDCT and dynamic phase MRI alone. The specificity and PPV of US was significantly lower than that of MDCT, dynamic phase MRI and dynamic + hepatobiliary phase MRI. Similar results were obtained for all sub-group analyses, with particular benefit for the diagnosis of smaller lesions between 1 and 2 cm.

Conclusions

Dynamic + hepatobiliary phase MRI improved detection and characterisation of HCC in cirrhotic patients. The greatest benefit is for diagnosing lesions between 1 and 2 cm.

Key Points

? US, CT and MRI can all identify HCC in cirrhotic patients ? US has good sensitivity but suffers from false-positive findings ? Dynamic CT and MR have similar diagnostic performance for diagnosing HCC ? Dynamic + hepatobiliary phase MRI significantly improves detection and characterisation of HCC ? The greatest benefit is for the diagnosis of lesions between 1 and 2 cm     

MR-PET fusion imaging in evaluating adnexal lesions: a preliminary study

Purpose

The objective of this preliminary study was to examine the effects of combined magnetic resonance/positron emission tomography (MR-PET) evaluation in the morphofunctional characterisation of ovarian lesions.

Materials and methods

From June 2008 to September 2010, we evaluated 24 patients (mean age 44±10 years; range 24?C74) with ovarian lesions incidentally detected on ultrasonography (US) and/or multislice computed tomography (CT). All patients underwent MR imaging of the pelvis and total-body CT-PET. PET and MR images were subsequently fused at postprocessing using specific anatomical criteria. Results were compared with the histological examination.

Results

Of the 24 examined lesions, 19 were malignant and five were benign on histological examination. MR, CT-PET and MR-PET sensitivity was 84%, 74% and 94%, respectively and specificity 60%, 80% and 100%, respectively. Positive (PPV) and negative predictive (NPV) values were 93% and 44% for CT-PET, 89% and 50% for MR and 100% and 83% for MR-PET, respectively.

Conclusions

Pelvic MR-PET fusion imaging provides advantages in terms of sensitivity and especially specificity compared with MR imaging or CT-PET alone. The added value of this fusion imaging modality lies in combining the benefits of the morphological evaluation provided by MR imaging and the metabolic assessment provided by PET.     

Probability of malignancy for lesions detected on breast MRI: a predictive model incorporating BI-RADS imaging features and patient characteristics

Objectives

To predict the probability of malignancy for MRI-detected breast lesions with a multivariate model incorporating patient and lesion characteristics.

Methods

Retrospective review of 2565 breast MR examinations from 1/03?C11/06. BI-RADS 3, 4 and 5 lesions initially detected on MRI for new cancer or high-risk screening were included and outcomes determined by imaging, biopsy or tumor registry linkage. Variables were indication for MRI, age, lesion size, BI-RADS lesion type and kinetics. Associations with malignancy were assessed using generalized estimating equations and lesion probabilities of malignancy were calculated.

Results

855 lesions (155 malignant, 700 benign) were included. Strongest associations with malignancy were for kinetics (washout versus persistent; OR 4.2, 95% CI 2.5?C7.1) and clinical indication (new cancer versus high-risk screening; OR 3.0, 95% CI 1.7?C5.1). Also significant were age >?=?50?years, size >?=?10?mm and lesion-type mass. The most predictive model (AUC 0.70) incorporated indication, size and kinetics. The highest probability of malignancy (41.1%) was for lesions on MRI for new cancer, >?=?10?mm with washout. The lowest (1.2%) was for lesions on high-risk screening, <10?mm with persistent kinetics.

Conclusions

A multivariate model shows promise as a decision support tool in predicting malignancy for MRI-detected breast lesions.     

Prospective evaluation of magnetic resonance enterography for the detection of mesenteric small bowel tumours

Purpose

To prospectively evaluate magnetic resonance (MR) enterography for detecting mesenteric small-bowel tumours (MSBTs) and assess the added value of gadolinium-chelate injection.

Material and methods

Over a 2-year period MR enterography examinations of 75 patients (33 men, 42 women; mean age, 53.8 years; range, 19–85) with suspected MSBT were blindly analysed by two readers for the presence of MSBT. Sensitivities, specificities, predictive positive values (PPVs), negative predictive values (NPVs) and accuracies of MR enterography for the detection of MSBT were calculated on per-patient and per-lesion bases. The McNemar test was used to compare sensitivities and specificities of the unenhanced and gadolinium-enhanced sets of MR enterographies.

Results

Thirty-seven MSBTs were pathologically confirmed in 26 patients. The mean tolerance score of the examinations was 0.7. On a per-patient basis, sensitivity, specificity, PPV, NPV and accuracy for detection of MSBT were 96 % [95 % CI, 89–100 %], 96 % [90–100 %], 93 % [83–100 %], 98 % [94–100 %] and 96 % [92–100 %], respectively. On a per-lesion basis, sensitivity and PPV were 70 % [56–85 %] and 93 % [83–100 %], respectively. Gadolinium injection yielded higher sensitivities on both bases (P?=?0.008).

Conclusion

MR enterography is an accurate and well-tolerated imaging modality for detecting MSBT. Intravenous administration of gadolinium-chelate improves sensitivity for MSBT detection.

Key Points

? MR enterography accurately detects mesenteric small bowel tumours. ? MR enterography is a well-tolerated imaging technique. ? Intravenous administration of gadolinium chelate improves sensitivity for detecting small-bowel tumours.     

Value of strain-ratio on thyroid real-time sonoelastography

Purpose

The aim of this study was to determine the accuracy of elastosonography in the differential diagnosis of thyroid nodules using a qualitative [evaluation of the stiffness score (SS)] and quantitative assessment [evaluation of the strain ratio (SR)].

Materials and methods

In our single-centre retrospective study, 368 patients were enroled between December 2010 and March 2012 (134 men, 234 women, mean age 56.1 ± 14.2) with a diagnosis of thyroid nodules, who underwent conventional ultrasonographic and elastosonographic evaluation. The SS and SR were assessed and the results were expressed in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The nodules were subjected to needle aspiration.

Results

Forty-four nodules were malignant (TIR ≥ 3) and 324 benign on cytological analysis. Considering a cut-off of SS > 2, we had 91 % sensitivity, 68 % specificity, 27 % PPV and 98 % NPV. Considering a cut-off of SR ≥ 3.28, we had 81.8 % sensitivity, 82.7 % specificity, 39.1 % PPV and 97.1 % NPV.

Conclusions

The SR calculation did not provide additional data to the SS, which remains the elastosonography benchmark. It will be necessary to validate these preliminary data by larger prospective randomised trials.     

Tomosynthesis-guided vacuum-assisted breast biopsy: A feasibility study

Purpose

Evaluation of feasibility and clinical performance of a tomosynthesis-guided vacuum-assisted breast biopsy (TVAB) system compared to Stereotaxy (SVAB).

Materials and methods

All biopsies were performed on consecutive patients: 148 TVAB biopsies and 86 biopsies on different patients using SVAB. Evaluation criteria for each biopsy were technical feasibility, histopathology, procedure time, and complications.

Results

All 148 TVAB biopsies were technically successful, and gained the targeted groups of microcalcifications (100 %). In 1 of 86 SVAB procedures, it was not possible to gain the targeted microcalcifications (1 %), in 3 of 86 the needle had to be adjusted (4 %). All TVAB biopsies were performed without clinically relevant complications. Distortions were biopsied exclusively by TVAB, mean size 0.9 cm, p?<?0.0001. Of the 24 distortions, 13 were cancer, 11 Radial Scars/ CSL. The mean procedure time for TVAB was 15.4 minutes (range 7–28 min), for SVAB 23 minutes (range 11–46 min), p?<?0.0001.

Conclusions

TVAB is able to biopsy small architectural distortions with high accuracy. TVAB is easily feasible and appears to have the same degree of clinical performance for diagnosing microcalcifications. The increased number of biopsied distortions by TVAB is presumably due to increased use of tomosynthesis and its diagnostic potential.

Key points

? TVAB is easily feasible.? TVAB is able to target architectural distortions with high accuracy.? TVAB diagnoses microcalcifications with the same clinical performance as SVAB.

     

Malignancy rate of biopsied suspicious bone lesions identified on FDG PET/CT

Purpose

To determine the malignancy rate of bone lesions identified on FDG PET/CT in patients who have undergone CT-guided biopsy because of the suspicion of malignancy.

Methods

This single-centre retrospective study spanned eight consecutive years and included all patients who underwent both FDG PET/CT and CT-guided bone biopsy because of the suspicion of malignancy. The positive predictive value (PPV) for malignancy was calculated, and different patient and imaging characteristics were compared between malignant and benign bone lesions.

Results

Of 102 included patients with bone lesions that all showed FDG uptake exceeding mediastinal uptake, bone biopsy showed a malignant lesion in 91 patients, yielding a PPV for malignancy of 89.2 % (95 % CI 81.7 – 93.9 %). In the 94 patients with bone lesions that showed FDG uptake exceeding liver uptake, bone biopsy showed a malignant lesion in 83 patients, yielding a PPV for malignancy of 88.3 % (95 % CI 80.1 – 93.5 %). Higher age, bone marrow replacement of the lesion seen on CT, expansion of the lesion seen on CT, and presence of multifocal lesions on FDG PET/CT were significantly more frequent in patients with malignant lesions than in those with benign bone lesions (P?=?0.044, P?=?0.009, P?=?0.015, and P?=?0.019, respectively). Furthermore, there was a trend towards a higher incidence of cortical destruction (P?=?0.056) and surrounding soft tissue mass (P?=?0.063) in patients with malignant bone lesions.

Conclusion

The PPV for malignancy of suspicious bone lesions identified on FDG PET/CT is not sufficiently high to justify changes in patient management without histopathological confirmation. Nevertheless, ancillary patient and imaging characteristics may increase the likelihood of a malignant bone lesion.

     

Imaging features of sporadic breast cancer in women under 40 years old: 97 cases

Objectives

To evaluate characteristic features of mammography, ultrasound and magnetic resonance imaging (MRI) of sporadic breast cancer in women <40 years and to determine correlations with pathological and biological factors.

Methods

A retrospective review of radiological, clinicopathological and biological features of sporadic breast cancers for women under 40 years at our institution between 2007-2012 covering 91 patients. Mammography was available for 97 lesions, ultrasound for 94 and MRI for 38.

Results

The most common imaging features were masses, nearly all classified BI-RADS 4 or 5. On mammography microcalcifications alone accounted for 31 %, all suspicious. There were 42.6 % luminal B, 24.5 % luminal A, 19.1 % HER2-enriched and 10.6 % triple-negative (TN) tumours by immunohistochemistry. HER2 overexpression was correlated with the presence of calcifications at mammography (P?=?0.03). TN cancers more often had an oval shape and abrupt interface at ultrasound and rim enhancement on MRI. MRI features were suspicious for all cancers and rim enhancement of a mass was a significant predictor of triple-negative tumours (P?=?0.01).

Conclusions

The imaging characteristics of cancers in patients under 40 years without proven gene mutations do not differ from their older counterparts, but appear correlated to phenotypic profiles, which have a different distribution in young women compared to the general population.

Key Points

? Young women have more luminal B/HER2+ phenotypes than older women. ? The appearance of cancers is correlated with their biological profiles. ? Sporadic breast cancer imaging in young women is generally classified BI-RADS 4/5. ? Triple-negative cancers can be misinterpreted as benign, requiring thorough imaging analysis.     

Diagnostic accuracy of post-mortem MRI for thoracic abnormalities in fetuses and children

Objectives

To compare the diagnostic accuracy of post-mortem magnetic resonance imaging (PMMR) specifically for non-cardiac thoracic pathology in fetuses and children, compared with conventional autopsy.

Methods

Institutional ethics approval and parental consent was obtained. A total of 400 unselected fetuses and children underwent PMMR before conventional autopsy, reported blinded to the other dataset.

Results

Of 400 non-cardiac thoracic abnormalities, 113 (28 %) were found at autopsy. Overall sensitivity and specificity (95 % confidence interval) of PMMR for any thoracic pathology was poor at 39.6 % (31.0, 48.9) and 85.5 % (80.7, 89.2) respectively, with positive predictive value (PPV) 53.7 % (42.9, 64.0) and negative predictive value (NPV) 77.0 % (71.8, 81.4). Overall agreement was 71.8 % (67.1, 76.2). PMMR was most sensitive at detecting anatomical abnormalities, including pleural effusions and lung or thoracic hypoplasia, but particularly poor at detecting infection.

Conclusions

PMMR currently has relatively poor diagnostic detection rates for the commonest intra-thoracic pathologies identified at autopsy in fetuses and children, including respiratory tract infection and diffuse alveolar haemorrhage. The reasonable NPV suggests that normal thoracic appearances at PMMR exclude the majority of important thoracic lesions at autopsy, and so could be useful in the context of minimally invasive autopsy for detecting non-cardiac thoracic abnormalities.

Key Points

? PMMR has relatively poor diagnostic detection rates for common intrathoracic pathology ? The moderate NPV suggests that normal PMMR appearances exclude most important abnormalities ? Lung sampling at autopsy remains the “gold standard” for pulmonary pathology     

Incidentally detected enhancing lesions found in breast MRI: analysis of apparent diffusion coefficient and T2 signal intensity significantly improves specificity

Objectives

To evaluate the value of adding T2- and diffusion-weighted imaging (DWI) to the BI-RADS® classification in MRI-detected lesions.

Methods

This retrospective study included 112 consecutive patients who underwent 3.0T structural breast MRI with T2- and DWI on the basis of EUSOMA recommendations. Morphological and kinetic features, T2 signal intensity (T2 SI) and apparent diffusion coefficient (ADC) findings were assessed.

Results

Thirty-three (29.5 %) patients (mean age 57.0?±?12.7 years) had 36 primarily MRI-detected incidental lesions of which 16 (44.4 %) proved to be malignant. No single morphological or kinetic feature was associated with malignancy. Both low T2 SI (P?=?0.009) and low ADC values (≤0.87?×?10^?3 mm²s^?1, P?<?0.001) yielded high specificity (80.0 %/80.0 %). The BI-RADS classification supplemented with information from DWI and T2-WI improved the diagnostic performance of the BI-RADS classification as sensitivity remained 100 % and specificity improved from 30 % to 65.0 %. The numbers of false positive lesions declined from 39 % (N?=?14) to 19 % (N?=?7).

Conclusion

MRI-detected incidental lesions may be challenging to characterize as they have few specific malignancy indicating features. The specificity of MRI can be improved by incorporating T2 SI and ADC values into the BI-RADS assessment.

Key Points

? MRI-detected incidental lesions have few specific malignancy indicating features. ? ≥ 1 suspicious morphologic or kinetic feature may warrant biopsy. ? T2 signal intensity and DWI assessment are feasible in primarily MRI-detected lesions. ? T2 SI and DWI assessment improve the BI-RADS specificity in MRI-detected lesions.

     

Usefulness of dynamic contrast-enhanced MRI in the evaluation of the viability of acute scaphoid fracture

Objective

To evaluate the usefulness of dynamic gadolinium-enhanced magnetic resonance imaging (MRI) for assessing the viability of the proximal pole of the scaphoid in patients with acute scaphoid fractures.

Methods

Eighteen consecutive patients with acute scaphoid fracture who underwent dynamic gadolinium-enhanced MRI 7 days or less before surgery were prospectively included between August 2011 and December 2012. All patients underwent MR imaging with unenhanced images, enhanced images, and dynamic enhanced images. A radiologist first classified the MRI results as necrotic or viable based on T1- and T2-weighted images only, followed by a second blinded interpretation, this time including analysis of pre- and post-gadolinium administration images and a third blinded interpretation based on the time–intensity curve of the dynamic enhanced study. The standard of reference was the histologic assessment of a cylindrical specimen of the proximal pole obtained during surgery in all patients. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for unenhanced, enhanced, and dynamic gadolinium-enhanced MRI studies.

Results

The sensitivity, specificity, PPV, and NPV were 67, 67, 50, and 80 % for unenhanced images, 83, 100, 100, and 92 for enhanced images, and 83, 92, 83, and 92 for dynamic contrast-enhanced images.

Conclusions

Our data are consistent with previously reported data supporting contrast-enhanced MRI for assessment of viability, and showing that dynamic imaging with time–intensity curve analysis does not provide additional predictive value over standard delayed enhanced imaging for acute scaphoid fracture.