“CADEAT”: considerations on the use of CAD (computer-aided diagnosis) in mammography

Computer-aided diagnosis (CAD) has been extensively reported to increase sensitivity by about 10% when added to a single reading while increasing recall rate by 12%, and its current use can be safely recommended in clinical practice. CAD has been suggested as a possible alternative to conventional double reading in screening. Uncontrolled comparison is consistent and suggests that CAD is comparable to double reading in incremental cancer detection rate (CAD +10.6%, double reading +9.1%) and possibly better in recall rate (CAD +12.5%, double reading +28.8%). However, controlled studies comparing single reading + CAD to conventional double reading are not consistent and on average suggest a lower cancer detection rate (?5.1%) and a lower recall rate (?9.8%) for CAD. Scientific evidence is not sufficient for a safe recommendation of single reading + CAD as a current alternative to conventional double reading.     

Does registration of serial MRI improve diagnosis of dementia?

Introduction

We aimed to assess the value of a second MR scan in the radiological diagnosis of dementia.

Methods

One hundred twenty subjects with clinical follow-up of at least 1 year with two scans were selected from a cognitive disorders clinic. Scans were reviewed as a single first scan (method A), two unregistered scans presented side-by-side (method B) and a registered pair (method C). Scans were presented to two neuroradiologists and a clinician together with approximate scan interval (if applicable) and age. Raters decided on a main and subtype diagnosis.

Results

There was no evidence that differences between methods (expressed as relative odds of a correct response) differed between reviewers (p?=?0.17 for degenerative condition or not, p?=?0.5 for main diagnosis, p?=?0.16 for subtype). Accordingly, results were pooled over reviewers. For distinguishing normal/non-progressors from degenerative conditions, the proportions correctly diagnosed were higher with methods B and C than with A (p?=?0.001, both tests). The difference between method B and C was not statistically significant (p?=?0.18). For main diagnosis, the proportion of correct diagnoses were highest with method C for all three reviewers; however, this was not statistically significant comparing with method A (p?=?0.23) or with method B (p?=?0.16). For subtype diagnosis, there was some evidence that method C was better than method A (p?=?0.01) and B (p?=?0.048).

Conclusions

Serial MRI and registration may improve visual diagnosis in dementia.     

⁶⁸Ga-labelled peptides for diagnosis of gastroenteropancreatic NET

In the past few years, the introduction of novel PET tracers labelled with (68)Ga has changed the diagnostic approach to neuroendocrine tumours (NET) in specialized centres. Although somatostatin analogue tracers labelled with (111)In have represented the gold standard imaging modality for NET detection in past decades, the advantages offered by both labelling somatostatin analogues with (68)Ga and using PET/CT tomography for image acquisition, account for the increasing use of these tracers in clinical practice. There are an increasing number of reports of the higher accuracy of (68)Ga-DOTA peptide PET/CT for the detection of NET lesions as compared to morphological imaging procedures and somatostatin receptor scintigraphy. Moreover, the use of (68)Ga-DOTA peptides offers the possibility to noninvasively evaluate NET cells for the presence of somatostatin receptor expression, with direct therapeutic implications. Several practical advantages also favour the use of (68)Ga-DOTA peptides including the relatively easy and economic synthesis process and the fact that (68)Ga labelling can be performed in centres without an on-site cyclotron. We describe the advantages and limitations of (68)Ga-DOTA peptide PET/CT imaging for the assessment of gastroenteropancreatic NET referring to the available literature as well as to our experience, and finally highlight potential future perspectives.     

Role of CT in the diagnosis of jejunal–ileal perforations

Purpose

The purpose of this study was to evaluate the computed tomography (CT) signs of free and covered small-bowel perforations and the potential of CT in recognising the aetiology.

Materials and methods

Thirty-five patients with surgically proven small-bowel perforation were retrospectively evaluated. Fundamental signs (extraluminal air, solution of continuity) and secondary signs (thickening of the mesentery, free or perilesional fluid, wall thickening) were considered.

Results

CT alterations were found in 31/35 (88.6 %) patients: extraluminal air (30/35, 85.7 %), solution of continuity (11/35, 31.4 %), intra-abdominal fluid (27/35, 77.1 %), thickening of the mesentery (20/35, 57.1 %), and wall thickening (14/35, 40 %). In 25/35 cases (71.4 %) pneumoperitoneum was detected, associated with secondary signs (23/25, 82 %), confirmed as free perforations at surgery. In 5/35 patients (14.2 %), peri-intestinal air bubbles and secondary signs were evident, while in 1/35 cases (2.8 %) only secondary signs were seen, namely covered perforations. In 4/35 patients (11.4 %) with a covered perforation, the CT scan was negative. The nature of the perforations was completely recognisable in 26/31 cases (83.9 %), partially identifiable in 4/31 (12.9 %), not evident in 1/31 (3.2 %).

Conclusion

CT investigation is essential in the recognition of a small-bowel perforation and in the definition of its nature.     

Computer-assisted diagnosis (CAD) in mammography: comparison of diagnostic accuracy of a new algorithm (Cyclopus®, Medicad) with two commercial systems

Purpose

The study compares the diagnostic accuracy (correct identification of cancer) of a new computer-assisted diagnosis (CAD) system (Cyclopus) with two other commercial systems (R2 and CADx).

Materials and methods

Cyclopus was tested on a set of 120 mammograms on which the two compared commercial systems had been previously tested. The set consisted of mammograms reported as negative, preceding 31 interval cancers reviewed as screening error or minimal sign, and of 89 verified negative controls randomly selected from the same screening database.

Results

Cyclopus sensitivity was 74.1% (R2=54.8%; CADx=41.9%) and was higher for interval cancers reviewed as screening error (90.9%; R2=54.5%; CADx=81.8%) compared with those reviewed as minimal sign (65.0%; R2=55.0%; CADx=20.0%). Specificity was 15.7% (R2=29.2%; CADx=17.9%). Overall accuracy was 30.8% (R2=35.8%; CADx=24.1%). The positive predictive value of a case with CAD marks [regions of interest (ROI)] was 23.4% (23/98; R2=16.0%; CADx=15.1%). Average ROI number per view among negative controls was 1.13 (R2=0.93; CADx=0.99). Cyclopus was more sensitive for masses compared with isolated microcalcifications (208 vs 62 ROI; R2=90 vs 213; CADx=192 vs 130).

Conclusions

Compared with two other commercial systems, Cyclopus was more sensitive (R2 p=0.14; CADx p=0.02) and less specific (R2 p=0.02; CADx p=0.64).     

Erroneous diagnosis of subperiosteal osteoid osteoma: value of imaging techniques?

A case of subperiosteal osteoid osteoma of the tibia misdiagnosed as stress fracture based on a history of multiple trauma and the results at MRI and bone scintigraphy is described. The nidus was well demonstrated at CT and the diagnosis was confirmed at histology. The role of different imaging techniques and their pitfalls are discussed.     

Utility of dynamic perfusion PET using ¹³N-ammonia in diagnosis of asymptomatic recurrence of fibrosarcoma

Fibrosarcoma is a rare tumor involving the musculoskeletal system. Anatomic imaging modalities like CT and MRI are useful in characterization and staging of the tumor. FDG PET has variable sensitivity in evaluation of these tumors. Alternative tracers like FLT have been tried. It is a well-known fact that sarcomas are highly vascular. We report the utility of dynamic perfusion PET imaging using N13-ammonia in diagnosing a case of asymptomatic recurrence of fibrosarcoma in a 45-year-old patient. Despite very faint FDG avidity, ammonia perfusion imaging showed hypervascularity and allowed identification of the asymptomatic early recurrence.     

Neuroimaging diagnosis of pineal region tumors—quest for pathognomonic finding of germinoma

Introduction

Our study aimed to elucidate the imaging features for the differentiation of pineal germinoma and other pineal region tumors.

Methods

Image data sets of computed tomographic (CT) scan and magnetic resonance imaging (MRI) data of 93 pineal region tumors including 33 germinomas, 30 nongerminomatous germ cell tumors (NGGCTs), 20 pineal parenchymal tumors (PPTs), and 10 miscellaneous tumors of pineal region were reviewed. Imaging features on CT and MRI were qualitatively assessed by three readers. To know the reasons for morphological differences between germinomas and NGGCTs, histological investigation was done.

Results

Localized calcification was seen in more than 70 % of germ cells tumors (GCTs: germinomas and NGGCTs) while it was scattered in more than half of PPTs. Cystic components in tumors were most frequent in NGGCTs (62 %). Multiplicity of lesion was restricted to GCTs: 39.4 % in germinoma and 10.0 % in NGGCTs. Thick peritumoral edema was more frequent in germinoma than in NGGCT: 40.6 vs. 14.8 % (p?=?0.0433, Fisher’s test). Bithalamic extension of tumor was seen in 78.8 % of germinomas. It was significantly rare in other groups of tumors (p?<?0.0001, Fisher’s test). The relative collagen amount per unit area was significantly lower in germinoma than in NGGCTs.

Conclusion

By paying attention to characteristic features as bithalamic extension, thick peritumoral edema, calcification pattern, multiplicity, and their combination, the preoperative differential diagnosis of pineal germinoma will become more accurate.     

The role of bone scan in the diagnosis of Jaffé-Lichtenstein-Uehlinger syndrome

The case of a 12-year-old girl with Jaffé-Lichtenstein-Uehlinger syndrome is presented. A bone scan pattern exhibits clinical symptoms, X ray images and histological findings are described in a case of polyostotic form of the fibrous dysplasia. A biopsy with histology was performed in consideration of bone scan findings and a confirmed final diagnosis.     

Role of imaging methods in diagnosis and treatment of Morton’s neuroma

Among the many causes of forefoot pain, Morton’s neuroma (MN) is often suspected, particularly in women, due to its high incidence. However, there remain controversies about its relationship with symptomatology and which diagnostic and treatment choices to choose. This article mainly focuses on the role of the various imaging methods and their abilities to support an accurate diagnosis of MN, ruling out other causes of forefoot pain, and as a way of providing targeted imaging-guided therapy for patients with MN.